CN108145899B

CN108145899B - Forming die of seat cushion

Info

Publication number: CN108145899B
Application number: CN201711212885.1A
Authority: CN
Inventors: 中尾知裕; 河野哲范
Original assignee: Toyota Boshoku Corp
Current assignee: Toyota Boshoku Corp
Priority date: 2016-12-02
Filing date: 2017-11-28
Publication date: 2020-04-10
Anticipated expiration: 2037-11-28
Also published as: CN108145899A; JP2018089092A

Abstract

The invention provides a forming die for a seat cushion. A forming die for a foam-formed seat cushion comprises: a lower die (11); an upper die (12); a standing wall portion (11b) which extends in a convex shape in a vertical direction perpendicular to the width direction in a plan view and which protrudes upward from the lower mold (11); an injection surface portion (11a1) formed on the inner side of the convex shape of the standing wall portion (11b) and receiving a foaming resin material injected at the time of foam molding; and a plurality of banks (11d) formed on the convex outer side of the standing wall (11b), protruding upward along the standing wall (11b) in parallel with the standing wall (11b) at a height lower than the standing wall (11b), and arranged at predetermined intervals.

Description

Forming die of seat cushion

Technical Field

The present invention relates to a molding die for a seat cushion of a vehicle seat mounted on a vehicle such as an automobile, an airplane, a ship, or a train.

Background

In a molding die for a seat cushion, which is a cushion body of a vehicle seat, there is known a molding die having a cavity formed into a predetermined shape, and into which a soft polyurethane foam material is injected to foam-mold the material. As shown in fig. 6, in a mold 50 for a seat cushion disclosed in japanese patent laid-open publication No. 2015-147312, a cavity 53 is formed between a molding surface of a lower mold 51 formed in a shape of a seating surface side of the seat cushion and a molding surface of an upper mold 52 formed in a shape of a rear surface side of the seat cushion. Two straight upright walls 54 extending in the seat width direction are formed in parallel in the substantially central portion of the molding surface of the lower die 51 so as to form a groove shape on the seating surface of the seat cushion. In the foam molding, the seat cushion is obtained by injecting the soft polyurethane foam material 55 into the molding surface of the lower mold 51 in a state where the upper mold 52 is opened with respect to the lower mold 51, then closing the upper mold 52, and allowing the mixture to stand for a predetermined time under heating to foam and solidify the mixture.

Disclosure of Invention

In the molding die 50 for a seat cushion, a standing wall 54 for forming a groove shape on a seating surface of the seat cushion is formed to linearly extend in a seat width direction. For example, when the soft polyurethane foam material 55 is injected into one side across the standing wall 54, the material expanded by foaming flows out to the other side beyond the standing wall 54, and when the other side fills the cavity 53 and foams and solidifies, it reaches the other side of the standing wall 54 substantially simultaneously and applies a pressing force. Accordingly, the soft polyurethane foam material 55 is foamed and cured at substantially the same time on the other side of the standing wall 54, and thus defects such as voids are less likely to occur. On the other hand, when viewed from a direction perpendicular to the seating surface, the groove shape formed in the seating surface of the seat cushion may be convex in the in-plane direction. At this time, the standing wall is also formed in a convex shape. In the above case, when the soft polyurethane foam material 55 is injected into the convex inner side which is one side with the standing wall therebetween, the material expanded by foaming flows out to the other side across the standing wall, and when the other side fills the cavity 53 and foams and solidifies, the time for reaching the other side of the standing wall and bringing a pressing force varies depending on the part of the standing wall. That is, the raw material reaches the vicinity of the top of the convex shape in a state where the raw material is not foamed and solidified, whereas the raw material reaches the end of the convex shape in a state where the raw material is foamed and solidified. This reduces the fluidity of the foaming material at the convex end portion, and makes it difficult to adhere to the standing wall, thereby easily causing defects such as voids.

The invention provides a mold for a seat cushion, which is provided with a cavity for molding the seat cushion between a lower mold and an upper mold, and is difficult to generate defects during polyurethane foam molding even if a vertical wall which is convex along the in-plane direction in a planar view is formed on the cavity surface of the lower mold.

The forming die of the present invention is a forming die for a seat cushion formed by foam molding, and includes: a lower die; an upper die for forming a cavity for molding the seat cushion between the upper die and the lower die; a standing wall portion formed at a portion corresponding to a seating surface of the seat cushion in a molding surface of the lower mold on which the cavity is formed, the standing wall portion extending convexly in a vertical direction perpendicular to a seat width direction from both end portions in the seat width direction in a plan view, and protruding upward of the molding surface; an injection surface portion formed on the molding surface on the inner side of the convex shape of the standing wall portion and receiving at least a part of a foaming resin material injected into the cavity at the time of foam molding; and a plurality of banks formed on the molding surface outside the convex shape of the standing wall portion, protruding upward along the standing wall portion in parallel with the standing wall portion at a height lower than the standing wall portion, and arranged at predetermined intervals.

According to the above aspect, when the foaming resin material is injected into the cavity during the foam molding of the seat cushion, at least a part of the foaming resin material foams and flows out from the injection surface side of the standing wall portion to between the banks over the standing wall portion. At this time, the foaming resin material is once accumulated between the convex outer side of the standing wall portion and the plurality of banks, and then flows over the upper portions of the plurality of banks or the portions without banks at predetermined intervals to the convex outer molding surface of the standing wall portion, and foams. When the cavity is filled with the foamed foaming resin material, the foaming resin material is accumulated between the outer side of the convex shape of the standing wall portion and the plurality of banks, and therefore, a void is less likely to be generated in the outer side portion of the convex shape of the standing wall portion, and occurrence of defects such as voids can be suppressed. Here, the convex outer side of the standing wall portion means one side in the direction in which the standing wall portion protrudes in the in-plane direction in a plan view, and the convex inner side of the standing wall portion means the opposite side in the direction in which the standing wall portion protrudes in the in-plane direction in a plan view.

In the above aspect, the height of the injection surface portion in the vertical direction may be higher than the molding surface on the outer side of the convex shape of the standing wall portion.

According to the above configuration, the foaming resin material injected into the injection surface portion easily flows out between the banks at a high flow rate over the standing wall portion. Thus, in the case of such a molding die, if a plurality of banks are provided and the foaming resin material is temporarily accumulated between the convex outer side of the standing wall portion and the plurality of banks, the effect of suppressing occurrence of defects such as voids is remarkable as compared with the case where a plurality of banks are not provided.

In addition to the above aspect, the height of the dam portions protruding from the molding surface may be 1/6 to 1/2 as measured from the molding surface.

According to the above configuration, since the heights of the plurality of banks are set to a level necessary for suppressing occurrence of defects such as voids, it is possible to suppress occurrence of defects such as voids and easily release the foam-molded seat cushion from the molding die without damage.

In addition to the above configuration, the distance between the plurality of banks and the standing wall portion in a plan view may be 1/3 to 3/4 as a projection height of the standing wall portion from the molding surface.

According to the above configuration, since the distance between the plurality of banks and the standing wall portion is set to a degree necessary for suppressing occurrence of a defect such as a void, occurrence of a defect such as a void can be suppressed, and the seat cushion after foam molding can be easily released from the molding die without damage.

In addition to the above configuration, the predetermined interval between the plurality of banks may be 1/5 to 1/2 of a length of the plurality of banks extending along the standing wall portion.

According to the above configuration, since the intervals between the plurality of banks are set to a degree necessary for suppressing occurrence of defects such as voids, it is possible to suppress occurrence of defects such as voids and easily release the foam-molded seat cushion from the molding die without damage.

Drawings

The features and advantages of the present invention described above and below will be apparent from the following description of the preferred embodiments with reference to the accompanying drawings, in which like reference numerals refer to like parts.

Fig. 1 is a plan view of a cushion pad formed using a molding die for a seat cushion according to an embodiment of the present invention, as viewed from a seating surface side.

Fig. 2 is a view in line II-II of fig. 1.

Fig. 3 is a view in line III-III of fig. 1.

Fig. 4 is a sectional view of the forming die of the seat cushion corresponding to fig. 2.

Fig. 5 is an enlarged view of a portion V of fig. 4.

Fig. 6 is a sectional view of a forming die for a seat cushion of the related art.

Detailed Description

Fig. 1 to 5 show an embodiment of the present invention. The molding die 10 of the present embodiment is a die for molding the cushion pad 1 made of foamed polyurethane shown in fig. 1, and the cushion pad 1 is disposed in a seat cushion pad of a front seat of an automobile. In the drawings, arrows indicate the respective directions of the automobile and the front seat when the cushion pad 1 is mounted in the front seat and attached to the automobile. In the following description, the description of the direction is made with reference to the direction. Here, the cushion pad 1 is an example of a "seat cushion" in the claims.

As shown in fig. 1 to 3, the cushion pad 1 is a cushion body made of soft urethane resin which is formed into a pad shape having a predetermined thickness and exhibits a moderate cushion feeling, and is deflected by a load of a seated person and supports the seated person by elastically exerting a reaction force. The cushion pad 1 has: a main portion 2 occupying the center in the seat width direction, and side support portions 3 occupying both right and left portions of the main portion 2. A longitudinal groove portion 4 extending in the front-rear direction is formed between the main portion 2 and the left and right side support portions 3. Further, the main portion 2 is formed with: a front lateral groove portion 5 connecting the vicinities of the front-rear direction center portions of the left and right vertical groove portions 4 and extending convexly forward; and a rear lateral groove portion 6 connecting rear portions in the front-rear direction of the left and right vertical groove portions 4 and linearly extending in the left-right direction. More specifically, the left and right vertical groove portions 4 extend substantially in parallel with each other in the front-rear direction at a position rearward of the front connecting portion 7, which is a connecting portion with the front horizontal groove portion 5. The left and right vertical groove portions 4 extend forward of the front connecting portion 7 so as to gradually separate from each other as they go forward. The front lateral groove portion 5 is formed in a smooth curved shape connecting the left and right front connecting portions 7 and passing through the apex portion 5a, and the apex portion 5a is a position projecting most forward at the center portion in the left-right direction of the front lateral groove portion 5. The distance in the front-rear direction from the front end of the cushion pad 1 to the top portion 5a is approximately half the distance in the front-rear direction from the front end of the cushion pad 1 to the front connecting portion 7. The distance in the front-rear direction from the rear end of the cushion pad 1 to the rear lateral groove portion 6 is set to be substantially equal to the distance in the front-rear direction from the front end of the cushion pad 1 to the top portion 5 a. The left and right vertical groove portions 4, the front horizontal groove portion 5, and the rear horizontal groove portion 6 function as grooves for drawing and fastening each portion of a cushion cover (not shown) as a skin material covering the cushion pad 1 into the cushion pad 1. Fastening threads (not shown) for fastening the cushion cover are fitted into the bottoms of the left and right vertical groove portions 4, the front horizontal groove portion 5, and the rear horizontal groove portion 6.

As shown in fig. 1 to 3, the main portion 2 is formed such that a portion forward of the front horizontal groove portion 5 gradually protrudes upward toward the front, and mainly supports the vicinity of the front end portion of the thigh portion of the seated occupant. The main portion 2 is formed substantially horizontally at a portion rearward of the front lateral groove portion 5, and mainly supports the seated occupant from the base of thighs to the buttocks. The left and right side supporting portions 3 are each formed in a shape that projects upward in a mountain shape from the left and right vertical groove portions 4 toward both outer sides, and are portions that support the hip or the side portion of the thigh of the seated occupant from the outer side.

As shown in fig. 2, the front lateral groove portion 5 and the rear lateral groove portion 6 are formed in a substantially U-shape in cross section that opens upward, and have a depth of about 20 to 30mm and a width of about 10mm from the seating surface side surface of the main portion 2. As shown in fig. 3, the vertical groove portion 4 is formed in a substantially U-shape in cross section that opens upward, and has a depth of about 20 to 30mm and a width of about 10mm from the seating surface side surface of the main portion 2. That is, the front lateral groove portion 5, the rear lateral groove portion 6, and the vertical groove portion 4 are formed to have substantially the same cross-sectional shape.

As shown in fig. 1 and 2, seven shallow grooves 8 are formed in bilateral symmetry on the front side of the front transverse groove portion 5 corresponding to the outer side of the convex shape in plan view. The seven shallow grooves 8 have the same cross section and are substantially U-shaped and open upward, and have a depth of about 5 to 10mm and a width of about 3 to 5mm from the seating surface side surface of the main portion 2. The seven shallow grooves 8 are arranged substantially parallel to the front horizontal groove portion 5 along a line which is spaced forward from the center line of the front horizontal groove portion 5 by about 10 to 15mm in a plan view. The seven shallow grooves 8 have a length of about 30 to 50mm in plan view, and the interval between adjacent shallow grooves 8 is about 10 to 15 mm. The seven shallow grooves 8 are formed in the vicinity of the front surface of the front transverse groove portion 5 by a weir 11d provided in the molding die 10 to suppress occurrence of a defect such as a void when the cushion pad 1 is foam-molded as described later, and do not function as a product of the cushion pad 1. That is, as a product of the cushion pad 1, the smaller the seven shallow grooves 8, the better.

As shown in fig. 2 and 3, the surface of the cushion pad 1 on the side opposite to the seating surface is formed in the following shape: a thick air-permeable nonwoven fabric (not shown) is integrally formed, and can be placed in a shape suitable for the cushion frame as a framework.

A mold 10 for molding the cushion pad 1 will be described with reference to fig. 1, 4, and 5. The forming die 10 includes: a lower mold 11 having a lower molding surface 11a for molding an upper surface portion which is a seating surface portion of the cushion pad 1; and an upper mold 12 having an upper molding surface 12a for molding a lower surface portion, which is a rear surface portion of the cushion pad 1. A cavity portion surrounded by the lower molding surface 11a of the lower mold 11 and the upper molding surface 12a of the upper mold 12 is a cavity 13, and the shape of the cavity 13 corresponds to the shape of the cushion pad 1. As shown in fig. 4, a front standing wall portion 11b, a rear standing wall portion 11c, and a dam 11d stand on a lower molding surface 11a of the lower mold 11. The front upright wall 11b, the rear upright wall 11c, and the weir 11d are arranged in shapes and positions corresponding to the front lateral groove 5, the rear lateral groove 6, and the shallow groove 8 of the cushion pad 1, respectively. That is, the front standing wall portion 11b is formed so as to curve and extend convexly forward in a plan view, and has left and right side connecting portions (not shown) and a top portion 11b1 corresponding to the left and right front connecting portions 7 and the top portion 5a of the cushion pad 1. The dam 11d is disposed substantially parallel to the front standing wall 11b along a line which is spaced from the center line of the front standing wall 11b by about 10 to 15mm in a front view. Although not shown in fig. 4, left and right side standing wall portions corresponding to the left and right vertical groove portions 4 of the cushion pad 1 are also arranged. Here, the front standing wall portion 11b is an example of the "standing wall portion" in the claims. The lower forming surface 11a and the upper forming surface 12a are examples of "forming surfaces" in the claims.

As shown in FIG. 5, the front standing wall 11b has a cross-sectional height H1 of about 20 to 30mm and a width W1 of about 10 mm. The height H2 of the cross section of the weir 11d is about 5 to 10mm, and the width W2 is about 3 to 5 mm. The distance D between the center line of the cross section of the front standing wall 11b and the center line of the cross section of the weir 11D is about 10 to 15 mm. Seven banks 11d are provided corresponding to the shallow grooves 8 in fig. 1, each having a length of about 30 to 50mm, and a gap G (see fig. 1) between

adjacent banks

11d and 11d is about 10 to 15 mm. The lower molding surface 11a is formed to be substantially horizontal at a portion rearward of the rear standing wall portion 11c, and to be inclined upward (toward the lower mold) as it goes forward from the portion forward of the rear standing wall portion 11 c. Here, the height H1, the height H2, the distance D, and the gap G are examples of "the height of protrusion of the standing wall portion from the molding surface", "the height of protrusion of the weir from the molding surface", "the interval between the weir and the standing wall portion", and "the predetermined interval" in the claims, respectively.

An injection surface portion 11a1 on which the soft polyurethane foam material 20 is placed when the soft polyurethane foam material 20 is injected into the cavity 13 is provided on the lower molding surface 11a between the front standing wall portion 11b and the rear standing wall portion 11 c. When the soft polyurethane foam material 20 is injected into the cavity 13, the whole material remains in the state before foaming in the injection surface portion 11a 1. However, a part of the soft polyurethane foam material 20 may be injected to the front of the front standing wall portion 11b and left in a state before foaming. Since the lower molding surface 11a is formed so as to be inclined upward (toward the lower mold) in a portion forward of the rear standing wall portion 11c, the injected soft polyurethane foam material 20 flows over the front standing wall portion 11b while being foamed. Here, the soft polyurethane foam raw material 20 is an example of the "foam resin raw material" in the claims.

A locking mechanism (not shown) for preliminarily fixing the thick nonwoven fabric is provided on the upper molding surface 12a of the upper mold 12. Further, a seal member (not shown) is disposed as necessary on the parting surface portions of the lower die 11 and the upper die 12. The lower die 11 and the upper die 12 are adjusted to a predetermined temperature as needed.

A method for manufacturing the cushion pad 1 using the molding die 10 will be described. As shown in fig. 4, in a state where the upper mold 12 is opened with respect to the lower mold 11, a predetermined amount of the soft polyurethane foam raw material 20 is injected into the injection surface portion 11a1 of the lower mold 11, and the upper mold 12 is closed. Thereby, the soft polyurethane foam material 20 foams and expands to fill the cavity 13. At this time, the soft polyurethane foam raw material 20 that has flowed forward beyond the front standing wall portion 11b temporarily accumulates in the region between the front standing wall portion 11b and the weir 11d and flows forward beyond the weir 11d or from the gap between the weir 11d and the weir 11 d. When the molding material reaches the uppermost portion (the portion most recessed in the lower mold direction) of the lower molding surface 11a, the material foams upward at this point and expands. By the expansion accompanying the foaming, the soft polyurethane foam material 20 reaches the upper molding surface 12a of the upper mold 12 and fills the cavity 13 from the front to the rear. Then, the soft polyurethane foam material 20 is cured in a foamed state by maintaining the closed state for a predetermined time in a state where the cavity 13 is filled with the soft polyurethane foam material 20, thereby forming the cushion pad 1. Here, a part of the injected soft polyurethane foam material 20 foams and solidifies in a state of being accumulated in the region between the front standing wall portion 11b and the dam 11 d. Accordingly, as compared with the case where the soft polyurethane foam raw material 20 flows once to the uppermost portion of the lower molding surface 11a without the weir 11d, and then foams and expands rearward, a defect such as a void is less likely to occur on the front surface side of the front standing wall portion 11 b. In particular, in the vicinity of the connection portion of the front standing wall portion 11b to the left and right side standing wall portions, the soft polyurethane foam material 20 reaches in a further cured state, and thus defects such as voids are likely to occur. The upper mold 12 is opened to release the cushion pad 1 after molding from the lower mold 11. At this time, since the height, width, length, and distance from the front standing wall portion 11b of the weir 11d are appropriately set, it is possible to suppress occurrence of troubles such as breakage of the cushion pad 1.

While the specific embodiments have been described above, the present invention is not limited to the above-described appearance and configuration, and various modifications, additions, and deletions can be made within the scope not changing the gist of the present invention. For example, the following cases may be mentioned.

In the above embodiment, the top portion 5a of the front horizontal groove portion 5 of the cushion pad 1 is located forward, but the present invention is not limited thereto, and the top portion 5a of the front horizontal groove portion 5 may be located rearward.

In the above embodiment, the present invention is applied to the forming die 10 of the cushion pad 1 of the front seat of the automobile. However, the present invention is not limited to this, and may be applied to a molding die for a back cushion of a front seat of an automobile, or may be applied to a molding die for a cushion pad or a back cushion of a rear seat of an automobile. The present invention can also be applied to seats mounted on airplanes, ships, electric trains, and the like.

In the above embodiment, the front lateral groove portion 5 is formed in a shape curved and extended convexly forward in a left-right symmetrical manner in a plan view, but is not limited thereto, and may be formed in a shape in which the apex portion 11b1 is offset to either the left or the right instead of the left-right symmetrical manner. The same applies to the case of a shape extending convexly curved rearward.

Claims

1. A forming die for a foam-formed seat cushion, the forming die comprising:

a lower die (11);

an upper die (12) that forms a cavity (13) for molding the seat cushion between the upper die (12) and the lower die (11);

a standing wall portion (11b) that is formed in a portion of a molding surface of the lower mold (11) that forms the cavity (13) that corresponds to a seating surface of the seat cushion, extends convexly in a vertical direction perpendicular to the seat width direction from both end portions in the seat width direction in a plan view, and protrudes upward of the molding surface;

an injection surface portion (11a1) formed on the molding surface on the inner side of the convex shape of the standing wall portion (11b) and receiving at least a part of a foaming resin material injected into the cavity (13) at the time of foam molding; and

and a plurality of weirs (11d) formed on the molding surface on the outer side of the convex shape of the standing wall portion (11b), protruding upward along the standing wall portion (11b) in parallel with the standing wall portion (11b) at a height lower than the standing wall portion (11b), and arranged at predetermined intervals.

2. The forming die of claim 1, wherein,

the height of the injection surface portion (11a1) in the vertical direction is higher than the molding surface on the outer side of the convex shape of the standing wall portion (11 b).

3. The forming die of claim 1 or 2, wherein,

the protruding height of the plurality of dams (11b) from the forming surface is 1/6-1/2 of the protruding height of the standing wall parts (11b) from the forming surface.

4. The forming die of claim 3, wherein,

the distance between the plurality of banks (11d) and the vertical wall (11b) in a plan view is 1/3-3/4 of the projection height of the vertical wall (11b) from the forming surface.

5. The forming die of claim 4, wherein,

the predetermined intervals of the plurality of weirs (11d) are 1/5-1/2 of the length of the plurality of weirs (11d) extending along the standing wall portion (11 b).