JP2001327357A - Vehicle seat and forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a seat, carrying out a crushing and a urethane foaming simultaneously in a manufacture of the seat while enhancing a fitness of a body to of the seat to improve comfortableness. SOLUTION: Thie vehicular seat is composed of a surface layer part 19 with insert pads 1, 3 inserted in side parts 7, 9 formed integrally with main parts 11, 13 of the seat 5; the insert pads 1, 3 disposed at the inner parts of the main parts 11, 13; and an outer peripheral part 23 formed between the surface layer part 19 and the insert pads 1, 3. The outer peripheral part 23 is formed to be harder than the insert pads 1, 3 and the surface layer part 19. The whole of the side parts 7, 9 are thereby made harder than the main parts 11, 13 of the seat 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a molded foam used for an automobile seat, which improves the riding comfort while maintaining the stability of the automobile seat. Further, the present invention can be applied and diverted to various seats and cushions without being limited to automobile seats.

[0002]

2. Description of the Related Art Conventionally, there has been a demand for a seat for an automobile to improve the riding comfort against a roll or the like when the vehicle is running by increasing the body holding ability. With respect to this body holding ability, a method of inserting a high-density and hard plate-like elastic member into the inside of urethane foam constituting a sheet is described in JP-A-7-111925 and the like. However, there is a problem that the effect of improving the riding comfort is reduced due to the insertion into the urethane foam and the higher density than the urethane foam, so that the occupant feels a foreign object when sitting down. It is also required to improve productivity by eliminating the crushing step which takes a long time in the sheet manufacturing process. The crushing step is a step different from the urethane foam (urethane pad) foam molding step, and is a step of converting the foamed product from closed cells to open cells after foaming.

FIG. 9 is an enlarged schematic view of the surface of a conventional seat back 107. The seat back is constituted by an infinite number of cells 100, each cell 100 being a cell wall which is a thin film of resin, and a cell column 100 made of resin.
b. The inside of the cell 100 is air bubbles, and contains gas such as air and carbon dioxide. Conventional sheet crushing is performed by roll crushing, vacuum crushing, or the like. As shown in FIG. 10, the roll crushing is performed by compressing the space between a pair of upper and lower rolls 101, 101 from above and below through a urethane foam 105 placed on a belt conveyor 103, thereby forming a cell wall of the urethane foam 105. And is excellent in productivity. As shown in FIG. 11, vacuum crushing uses a vacuum crushing device 113 whose periphery is shielded by a door 111 that can be opened and closed, and a urethane foam 105 is housed inside the vacuum crushing device 113, and piping is performed. Vacuum crushing device 113 by sucking air from 115
Is made into a substantially vacuum state, and then the internal pressure is immediately released to atmospheric pressure by an atmosphere release valve 117. This is a method in which a cell wall is crushed by utilizing a pressure difference between vacuum and atmospheric pressure, and is used for crushing a seat pad containing a metal claim that cannot be roll-crushed. There are several other ways to squeeze cells of a form with a needle. However, in each method, cells of urethane foam are crushed to form open cells.

[0004] With respect to the crushing, a method disclosed in, for example, JP-A-8-294926 has been disclosed. According to this method, the manufacturing process of the skin to be attached to the pad can be shortened, and the improvement of the molding accuracy of the skin material and the pad material is expected. However, the crushing process has not been shortened or omitted in the seat cushion and the seat back.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems and improves the riding comfort by increasing the body-holding ability of an automobile seat, and simultaneously performs crushing in the urethane foaming step in the production of the seat. An object of the present invention is to provide a method for producing a foam molded article.

[0006]

In order to achieve the above object, a vehicle seat according to the present invention has an insert pad inserted into a side portion of a seat, and the side portion is formed integrally with a main portion of the seat. Surface layer portion, an insert pad disposed inside the main portion, and an outer peripheral portion formed between the surface layer portion and the insert pad, and further, the outer peripheral portion includes an insert pad and By forming the side portion harder than the surface portion, the entire side portion is configured to be harder than the main portion of the seat. According to the vehicle seat, since the side portions of the seat are made harder than the main portion, the occupant's body can be securely held even while the automobile is running, and there is no pain at the time of rolling, The touch feeling is also good.

In the method for molding a vehicle seat according to the present invention, the step of disposing an insert pad at a position corresponding to a side portion of the seat in the interior of a molding die;
Injecting a urethane raw material liquid into the inside of the molding die, impregnating the surface layer of the insert pad with the urethane raw material liquid, and closing the molding die to foam and solidify the urethane raw material liquid. It becomes. According to the molding method, the outer peripheral portion of the insert pad is harder than the other portions, and the entire side portion can be harder than the main portion.

Further, in one aspect of the method of forming a vehicle seat according to the present invention, a urethane raw material liquid is injected into a molding die, and the urethane raw material liquid is placed in a semi-cured state while the urethane raw material liquid is in a semi-cured state. By reducing the pressure to a substantially vacuum state using a vacuum device and then returning it to atmospheric pressure, crushing and foaming and solidification of the urethane raw material liquid are performed in a single step. The above molding method can be applied to both the seat cushion and the seat back, and according to this method, crushing, which has conventionally taken a long time, can be performed together with urethane foaming and solidification. Therefore, the number of steps can be reduced, and productivity can be improved and cost can be reduced.

According to another aspect of the method of forming a vehicle seat according to the present invention, an insert pad is disposed at a position corresponding to a side portion of the seat in the inside of the molding die, and a surface layer of the insert pad is provided. The method further comprises a step of impregnating the raw material liquid with a urethane raw material liquid. In addition,
Still another aspect of the method for forming a vehicle seat according to the present invention is configured such that the above-described forming die and the vacuum device are operated using air. If the power source is, for example, electricity, sparks or the like may occur, but if it is air, this is not the case.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings. [First Embodiment] [Sheet Structure] To increase the body holding ability of a sheet,
It is effective to improve the supportability by making the side portions harder than the main portion of the seat cushion or the seat back. In the present embodiment, FIG.
As shown in FIG.
Are inserted into the side portions 7 and 9 of the seat 5, the side portions 7 and 9 are harder than the main portions 11 and 13.

The seat 5 includes a seat cushion 15 for holding the occupant's legs and buttocks, and a seat back 17 for holding the occupant's back. Further, as described above, the seat cushion 15 and the seat back 17 are respectively provided with the main portions 11 and 13 located substantially at the center in the vehicle width direction, and the side portions disposed on both sides of the main portions 11 and 13. 7, 9 and the side portions 7, 9
Are formed in a convex shape toward the surface side. That is,
The side portion 7 of the seat cushion 15 in FIG. 1 bulges toward the upper side of the vehicle, and the side portion 9 of the seat back 17 bulges toward the front side of the vehicle, so that the back and waist of the occupant can be securely held. Is formed.

FIG. 2 is a sectional view of the seat cushion 15 taken along line AA. The main part 11 is formed substantially flat, and is softer and more elastic than the side part 7. The side part 7 includes a surface part 19 formed integrally with the main part 11, a soft insert pad 1 disposed at the center of the side part 7, and a part between the surface part 19 and the insert pad 1. And an outer peripheral portion 23 having a hard and supportive feeling. This outer peripheral portion 23
Is made to have a hardness higher than that of the insert pad 1 by impregnating the surface layer of the insert pad 1 with a urethane raw material liquid which is a raw material of the main portion 11. A through hole 25 formed by 47 (shown in FIG. 7 described later) is provided at the upper end.

[Structure of Mold] As shown in FIGS. 3 and 4, urethane foaming mold 27 having an airbag-type mold clamping structure has a urethane raw material liquid 2 as a foaming material.
9 is foamed and hardened in a molding die 27 to produce a urethane foam such as a sheet 5 for an automobile. For this reason, the urethane raw material liquid 29 is obtained by supplying two kinds of liquids A and B from a raw material liquid supply source (not shown) to the hose 3.
The liquid is fed to the injection head 35 via the injection heads 1 and 33, and injected from the injection head 35 into the lower mold 37.

The molding die 27 is composed of an upper die 39 and a lower die 37 made of aluminum for casting (for example, AC4C). When the upper die 39 is closed, a product is formed therein. Cavity 41 is provided. For this reason, the lower mold 37 is formed in a shape corresponding to the main parts 11 and 13 and the side parts 7 and 9 of the seat 5, and the upper mold 39 and the lower mold 37 have an inclined surface serving as a seal part. Mating surfaces 43 and 45 are provided, respectively. On the back side of the upper die 39, two insert pads 1 and 3 for inserting into the side portions 7 and 9 of the seat 5 are respectively arranged via stays 47. The stay 47 is detachably attached to the insert pads 1 and 3, and is configured to be freely detached from the insert pads 1 and 3 after the sheet 5 is formed. The attachment of the insert pads 1 and 3 is not limited to the upper die 39, and may be attached to the lower die 37 as shown in FIG.

As shown in FIG. 4, a large number of airbags 49 which are inflated by air pressure are provided at the bottom of the lower die 37. These airbags 4 are supplied from an air supply source (not shown).
The lower mold 37 is inflated when air enters the mold 9, thereby being fitted with the upper mold 39, and the upper mold 39 and the lower mold 37 are clamped in a sealed state.

[Urethane Pad Molding] When a urethane pad constituting the sheet 5 is molded using a molding die 27 as shown in FIGS. 3 and 4, a urethane raw material liquid 29 which is a raw material of the main portions 11 and 13 is formed. Since the air bubbles in the surface layer of the insert pads 1 and 3 are impregnated by being impregnated, only the outer peripheral portion 23 of the insert pads 1 and 3 becomes hard, so that the cross section as shown in FIG. This is urethane raw material liquid 2
This is because even when the foam 9 is foamed, the foam is broken due to the unevenness of the surface layer of the insert pads 1 and 3, and when the foam 9 is in contact with the insert pads 1 and 3, the foaming reaction does not sufficiently occur. Therefore, the side portions 7, 9 of the seat 5
By increasing the hardness, the occupant's body holding ability is improved, and when the occupant gets into and out of the vehicle, the lumbar portion or the like hits the side portions 7, 9 of the seat 5, and the stiff feeling of discomfort is eliminated.

[Insert Pads] Since the outer peripheral portions 23 of the insert pads 1 and 3 are hardened, the insert pads 1 and 3 must be softer than the main portions 11 and 13 in order to effectively use the elasticity of the inner layers. Preferably, urethane pads of the same type as the main portions 11 and 13 may be inserted into the side portions 7 and 9. No special treatment is applied to the surfaces of the insert pads 1 and 3.

The reason for using air instead of electricity as a power source for operating the molding die 27 is as follows. (1) The airbag 49 and the like generally operate in an air sequence circuit, but this circuit and air can be used, and the molding die 27 has an inexpensive and simple structure. (2) It is smaller and lighter, has a better appearance, is more stable in operation, and has fewer failures than the electric type.

[Second Embodiment] Next, a second embodiment will be described. The same contents as those in the first embodiment will be denoted by the same reference numerals, and description thereof will be omitted. The second embodiment is a method of simplifying a production process of the sheet 5 by performing a time-consuming crushing process and a urethane molding process in the production of the urethane pad constituting the sheet 5.

[Overview of Crushing] First, crushing will be described. The urethane pads of the sheet 5, especially recent high modulus foams called cold urethane or HR foam, are closed cell foam immediately after molding.
When the urethane foam is used as a product such as the sheet 5 while keeping the closed cell, the following problem occurs. (1) Because the foam molding is an exothermic reaction, the foam immediately after being removed from the molding die 27 has a surface of 40 to 80 ° C.
The temperature is 50 to 100 ° C inside, and the temperature of the molding die 27 is 40 to 80 ° C. Therefore, the foam is shrunk and deformed because the warm foam immediately after molding, and after a while, cools and the bubbles shrink. (2) If the urethane foam is a closed cell, the elastic force becomes too large as if it were a rubber ball, resulting in a seat pad with poor vibration damping ability and poor cushioning ability. (3) The sheet 5 has no air permeability and is easily stuffy. In order to eliminate these drawbacks, the step of converting closed-cell urethane foam into open-cell urethane foam is a crushing step, and as described above, roll crushing and vacuum crushing are mainly used.

[Structure of Mold] In the second embodiment, a mold 61 having the structure shown in FIG. 6 is used. This molding die 61 is obtained by adding a vacuum circuit to the molding die 27 shown in FIG. The above molding die 61
In the vicinity of the center of the upper die 39, an air vent hole 63 communicating with the cavity 41 in the molding die 61 is formed as shown in FIG. This air vent hole 63 is formed in a tapered shape whose diameter gradually decreases from the upper surface to the lower side.
A valve 69 connected to an air cylinder 67 via a rod 65 is provided. The valve 69 is configured to be movable up and down to open and close the air vent hole 63.

On the upper surface of the upper mold 39, a seal portion 71 covering the air vent hole 63 is formed. The seal portion 71 is closed by a wall surface and is connected to a substantially cylindrical vacuum accumulator 77 by a pipe 75 having a valve 73 configured to be openable and closable. The vacuum accumulator 77 is provided with a vacuum pump 79. Has been established.

[Sheet Manufacturing Method] Next, a method of manufacturing a urethane foam of a sheet 5 for an automobile using the molding die 61 according to the second embodiment is shown in FIG. Description will be made based on (10). (1) Injection of urethane raw material liquid First, as shown in FIG. 3, a predetermined amount of urethane raw material liquid 29 is injected into the lower die 37 of the molding die 61 by the injection head 35. (2) Closing the mold After the urethane raw material liquid 29 is injected, the upper mold 39 is closed. (3) Timer operation of lock air sequence of upper die and lower die When kicking a dock (not shown), air enters airbag 49 and lower die 37 is lifted, as shown in FIG.
And the lower mold 37 are completely sealed and locked. In addition, when the user kicks the timer, a timer of an air sequence box (not shown) operates. (4) Blockage of air release valve

Next, the timer set value of the air sequence box (the urethane raw material liquid 29 foams and swells and the upper mold 3
9 reaches a predetermined time (for example, 3 to 20).
Second), the air release valve 69 provided in the upper mold 39
Is lowered by the piston rod 65 of the air cylinder 67 to close the air vent hole 63. During this time, the following two reactions occur in the urethane raw material liquid 29 accommodated in the molding die 61, thereby producing a sponge-like urethane foam. Polymerization reaction (urethane bond): polyol + isocyanate → urethane polymer Foaming reaction: water + isocyanate → carbon dioxide + urea bond (5) Opening of valve of vacuum accumulator Vacuum accumulator 77 and vacuum pump 79 shown in FIG. When the valve 73 is opened, the piping 75
Air is sucked from the seal portion 71 through the
The pressure inside 1 becomes substantially vacuum.

(6) Opening of Air Release Valve Next, when the air release valve 69 is opened, air is sucked from the inside of the molding die 61 through the air release hole 63,
The pressure inside the molding die 61 is, for example, 0.05 to 0.5.
A substantially vacuum state of about 3 kgf / cm ² is obtained. The time required from (1) to (6) is about 60 to 120.
Seconds. (7) Closing of Air Vent Valve About 3 to 20 seconds after opening the air bleed valve 69, the air bleed valve 69 is closed.

(8) Unlocking the upper and lower dies and opening the air release valve When kicking the dock, the air in the airbag 49 is released and the lower die 37 is lowered. Is unlocked. The air release valve 69 is connected to the air cylinder 6.
7 is raised by the piston rod 65 of the
3 is released. (9) Removal of Product In this state, the upper mold 39 is rotated upward to open the mold, and urethane foam as a product is removed from the molding die 61. (10) Application of Release Agent Then, in preparation for the next production process, the upper mold 39 of the molding die 61
Then, a release agent (a solution obtained by dissolving wax in a solvent) is applied to the lower mold 37 by spraying. Then, the solvent is dried and vaporized, and the surface of the molding die 61 is coated with a release agent.

According to the above-mentioned production method, the urethane raw material liquid 29 is injected into the molding die 61, and the urethane raw material liquid 29 is not completely solidified (about 1 to 2 minutes after the injection), and the vacuum is applied for a short time. After maintaining the state, the pressure is returned to normal pressure again. As a result, the cell 81 before crushing shown in FIG. 8A is greatly expanded by the internal pressure as shown in FIG.
As shown in (c), the cells 81 still in an incompletely cured state.
Is broken at a normal pressure by a pressure difference to form an open-cell body 83.

Therefore, since the urethane foam taken out of the molding die 61 is already in the form of the open-cell foam 83, crushing in the subsequent step is unnecessary. In addition, this in-line crushing is a sheet which cannot be subjected to roll crushing because metal is inserted therein, and in which vacuum crushing is performed instead of the roll crushing. It is valid. According to the above-described method, vacuum crushing, which is a factor of increasing the production tact, can be performed simultaneously in the urethane foaming step, so that there is an advantage that productivity is improved and a work space is widened.

[0029]

EXAMPLES Next, the present invention will be described more specifically with reference to examples. First, a sheet 5 for an automobile having various densities and hardnesses was formed and mounted on the automobile, and then a vehicle running test was actually performed. As a result of comparing the body holding and the like while the vehicle is running and when getting on and off, the sheets 5 having the density and hardness shown in Tables 1 and 2 have the highest body holdability and good touch feeling.

[0030]

[Table 1]

[0031]

[Table 2]

Table 1 shows data on the seat cushion 15 and Table 2 shows data on the seat back 17.
The hardness was evaluated by 25% hardness according to JIS K6400.

[0033]

According to the present invention, the hardness can be changed for each part in one sheet. That is,
By making the side portions of the seat harder than the main portion, it is possible to improve the occupant's body holding ability during traveling of the vehicle or the like. Further, by performing the crushing step together with the urethane foaming and solidifying steps, the number of steps and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view of a vehicle seat according to the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a perspective view of a molding die for manufacturing the vehicle seat according to the first embodiment.

FIG. 4 is a sectional view taken along line BB of FIG. 3;

FIG. 5 is a perspective view showing a modified example of a molding die.

FIG. 6 is a cross-sectional view illustrating a molding die according to a second embodiment.

FIG. 7 is a flowchart illustrating a molding method according to a second embodiment.

8 (a) is a schematic diagram showing a cell before crushing, FIG. 8 (b) is a schematic diagram showing a cell in a vacuum state, and FIG. It is the schematic which shows the cell which became.

FIG. 9 is a schematic view showing a structure in which the surface of a conventional seat back is enlarged.

FIG. 10 is a perspective view showing a conventional roll crushing process.

FIG. 11 is a perspective view showing a conventional vacuum crushing process.

[Explanation of symbols]

 1,3 Insert pad 5 Seat 7,9 Side part 11,13 Main part 15 Seat cushion 17 Seat back 19 Surface part 23 Outer part 25 Through hole 27,61 Molding mold 29 Urethane raw material liquid 31,33 Hose 35 Injection head 37 Lower die 39 Upper die 41 Void portion 43,45 Mating surface 47 Stay 49 Airbag 63 Air vent hole 65 Rod 67 Air cylinder 69 Air vent valve 71 Seal part 73 Valve 75 Piping 77 Vacuum accumulator 79 Vacuum pump 81 Cell 83 Open cell

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) B29K 105: 04 B29K 105: 04 B29L 31:58 B29L 31:58

Claims (5)

[Claims] 1. An insert pad is inserted into a side portion of a seat, and the side portion is provided with a surface layer portion formed integrally with a main portion of the seat, an insert pad disposed inside the main portion, A vehicle seat comprising an outer peripheral portion formed between the surface layer portion and the insert pad, wherein the outer peripheral portion is formed to be harder than the insert pad and the surface layer portion so that the entire side portion is a seat. A vehicle seat characterized by being harder than the main part of the vehicle. 2. A step of disposing an insert pad at a position corresponding to a side portion of a sheet in a molding die, and injecting a urethane raw material liquid into the molding die to form a surface layer of the insert pad. A step of impregnating the urethane raw material liquid with the urethane raw material liquid, and a step of closing the molding die to foam and solidify the urethane raw material liquid. 3. A urethane raw material liquid is injected into a molding die, and while the urethane raw material liquid is in a semi-cured state, the pressure inside the molding die is reduced to a substantially vacuum state using a vacuum device, and then the pressure is increased. A method for forming a vehicle seat, wherein crushing and foaming and solidification of a urethane raw material liquid are performed in a single step by returning to an atmospheric pressure. 4. The method according to claim 3, further comprising the step of disposing an insert pad at a position corresponding to a side portion of the sheet in the inside of the molding die, and impregnating a surface layer of the insert pad with a urethane raw material liquid. The method for forming a vehicle seat according to claim 1. 5. The apparatus according to claim 2, wherein the molding die and the vacuum device are operated using air.
5. The method for forming a vehicle seat according to any one of claims 4 to 4.