JP5762447B2 - Shock absorber and manufacturing method thereof - Google Patents

Description

  The present invention relates to a method for producing a shock absorber by foaming a synthetic resin material with a mold, and a shock absorber produced by the method for producing the shock absorber.

  A shock absorber made of foamed synthetic resin such as rigid polyurethane foam is attached to a door trim of an automobile for absorbing energy (EA) during a side collision (side collision).

  This shock absorbing material is manufactured by foaming a synthetic resin raw material in a cavity of a mold. In Patent Document 1, the impact absorbing material is molded with its impact receiving surface facing downward in the cavity of the mold.

JP2011-225165A

  Usually, the synthetic resin raw material supplied into the cavity of the mold adheres to the bottom surface of the cavity, and expands from the bottom surface of the cavity toward the cavity ceiling surface and the cavity side surface during the foaming reaction. Therefore, as the synthetic resin raw material undergoing the foaming reaction approaches the cavity ceiling surface and the cavity side surface, the reaction proceeds and the viscosity increases, and the foaming reaction tends to slow down.

  Therefore, in the shock absorber produced in this way, there is a difference in the density of the foamed synthetic resin between the impact receiving surface side and the back surface side, or between the surface layer side and the inside side. May occur. In that case, the homogeneity of the foamed synthetic resin in each part of the shock absorbing material is lowered, and the performance may vary. This becomes more prominent as the impact absorbing material becomes larger.

  The present invention solves such problems, and a method for producing a shock absorber capable of improving the homogeneity of the foamed synthetic resin in each part of the shock absorber, and the shock absorber produced by this production method. The purpose is to provide materials.

The manufacturing method of an impact absorbing material of the present invention (Claim 1) is a method of manufacturing an impact absorbing material by foaming a synthetic resin raw material with a mold, and the impact absorbing material receives an impact from a collision object. A shock receiving surface to be received, and a back surface opposite to the shock receiving surface, and the manufacturing method of the shock absorbing material includes the shock absorbing material from the shock receiving surface side to the back surface side or the back surface. First to n-th parts (n is an integer of 2 or more) are sequentially divided from the side to the impact receiving surface side, and the first to n-th parts are sequentially foam-molded. the first partial molding step, the first portion is molded alone, and the mth (m is an integer of 2 to n) partial molding step (m-1). ) The m-th portion for constituting the m-th portion in a state where the molded body formed by the partial molding step is disposed in the cavity of the mold. Synthetic resin raw material is foamed by supplying into the cavity, the boundary surface between the second portion of the first portion, a recess recessed toward the impact receiving surface provided on the outer circumference extending in the boundary surface A bank-like portion surrounding the recess along the entire circumference is provided.

  According to a second aspect of the present invention, there is provided a method for producing an impact absorbing material according to the first aspect, wherein the first to n-th parts are made of synthetic resin raw materials having the same composition.

  According to a third aspect of the present invention, there is provided a method for producing the shock absorber according to the first aspect, wherein at least one of the first to n-th parts is made of a synthetic resin raw material having a different composition from the synthetic resin raw material constituting the other part. It is characterized by comprising.

  According to a fourth aspect of the present invention, there is provided a method for producing the shock absorber according to any one of the first to third aspects, wherein the shock absorber is a large-thick portion having a relatively large thickness between the shock receiving surface and the back surface. And a small thickness portion having a thickness between the impact receiving surface and the back surface smaller than the large thickness portion, and the large thickness portion and the small thickness portion are orthogonal to the thickness direction. The portion on the side of the impact receiving surface that is adjacent to each other in the direction of the thickness of the large-thickness portion protrudes from the shock-receiving surface of the small-thickness portion on the opposite side of the back surface side. It is a protruding part, and among the shock absorbers, the protruding part is constituted by the first part, and the back side part of the protruding part is constituted by the second to nth parts. It is a feature.

  According to a fifth aspect of the present invention, there is provided a method for producing a shock absorber according to any one of the first to fourth aspects, wherein n = 2.

  According to a sixth aspect of the present invention, there is provided a method for producing a shock absorber according to any one of the first to fifth aspects, wherein the shock absorber is a shock absorber for a vehicle interior.

The impact absorbing material of the present invention (invention 7) is manufactured by the impact absorbing material manufacturing method according to any one of claims 1 to 6 .

In the present invention, the impact absorbing material is divided into first to nth portions and subjected to foam molding. Therefore, compared to the case where the entire impact absorbing material is molded in a single foam molding process, the density difference of the foamed synthetic resin between the impact receiving surface side and the back surface side in each of the first to nth parts, and the surface layer The difference in density of the foamed synthetic resin between the side and the inner side can be reduced. Thereby, the homogeneity of the foamed synthetic resin in each part of the shock absorbing material can be improved. As a result, variation in the performance of the manufactured shock absorber can be prevented or suppressed.
Moreover, it is preferable to provide the recessed part which dents toward the impact receiving surface side in the boundary surface with the 2nd part of a 1st part. When constituted in this way, the synthetic resin raw material for the second part sprinkled on the boundary surface of the first part in the second part molding step is accumulated in this recess, and the side peripheral surface of the first part The synthetic resin material for the second part is prevented or suppressed from entering between the mold and the cavity inner surface of the mold, and the impact absorbing material can be molded more accurately.

  As described in claim 2, the first to nth parts of the shock absorbing material may be composed of synthetic resin raw materials having the same composition. In this case, it is possible to produce an impact absorbing material in which the entire impact absorbing material is made of a more homogeneous foamed synthetic resin.

  As in claim 3, at least one of the first to n-th portions of the shock absorbing material may be composed of a synthetic resin raw material having a different composition from the synthetic resin raw materials constituting the other portions. Thereby, it is possible to easily manufacture shock absorbers having different required characteristics at each portion (for example, shock absorbers having lower hardness on the back side than on the shock receiving side).

  When the shock absorbing material has the shape as defined in claim 4, when the overhanging portion of the shock absorbing material and the other portion are molded in a single foam molding process, the foamed synthetic resin in the cavity of the mold The flow of the air becomes complicated, or the distance that the foamed synthetic resin has to move before the foamed synthetic resin is filled in the cavity becomes long. Therefore, the entire shock absorber is made of a homogeneous foamed synthetic resin. It's not easy. Therefore, in this case, as described in claim 4, the overhanging portion of the shock absorbing material is constituted by the first portion, and the portion on the back side of the overhanging portion is constituted by the second to nth portions. Further, the homogeneity of the foamed synthetic resin in the overhanging portion of the shock absorbing material and the other portions can be made better.

  As described in claim 5, it is preferable that the shock absorbing material is composed of two parts, a first part and a second part. By comprising in this way, the homogeneity of the foaming synthetic resin in each part of a shock absorber can fully be improved, ensuring the mass productivity of a shock absorber.

  As described in claim 6, the present invention is suitable for a method for manufacturing a shock absorber for vehicle interior.

The impact absorbing material of the present invention (claim 7 ) manufactured by the method of manufacturing an impact absorbing material of the present invention has good homogeneity of the foamed synthetic resin in each part of the impact absorbing material. As a result, the shock absorber is more reliably provided with the required characteristics, and has less performance variation.

It is a perspective view of the impact-absorbing material which concerns on 1st Embodiment. It is sectional drawing which follows the II-II line of FIG. It is a perspective view of the 1st part of the shock absorber of FIG. It is sectional drawing of the metal mold | die which shows the manufacturing method of the impact-absorbing material of FIG. It is sectional drawing of the metal mold | die which shows the manufacturing method of the impact-absorbing material of FIG. It is sectional drawing which shows the modification of an impact-absorbing material. It is sectional drawing of the impact-absorbing material which concerns on 2nd Embodiment. It is sectional drawing of the metal mold | die which shows the manufacturing method of the shock absorber of FIG. It is sectional drawing of the metal mold | die which shows the manufacturing method of the shock absorber of FIG.

  Embodiments of the present invention will be described below with reference to the drawings. In the following embodiments, as an impact absorbing material (hereinafter sometimes abbreviated as EA material), an EA material for vehicle interior that is attached to a door trim of an automobile is illustrated, but the present invention is not limited to this. The EA material and its manufacturing method can also be applied.

[First Embodiment]
FIG. 1 is a perspective view of the EA material 1 according to the first embodiment, and FIG. 2 is a cross-sectional view taken along the line II-II in FIG. FIG. 3 is a perspective view of the first portion of the EA material 1. FIGS. 4 and 5 are cross-sectional views of a second partial molding die 20 (hereinafter sometimes simply referred to as the die 20) showing the method of manufacturing the EA material 1, respectively. 4 and 5 each show a cross section of a portion of the mold 20 corresponding to FIG.

<About the structure of the EA material 1>
The EA material 1 is formed by foaming a synthetic resin material such as hard polyurethane. In this embodiment, when the EA material 1 is attached to an automobile door trim (not shown), the lower surface of the EA material 1 in FIGS. 1 and 2 faces the door trim, and the EA material 1 in FIGS. The top side faces the outside of the car. At the time of a side collision of the automobile to which the EA material 1 is attached, the upper surface of the EA material 1 in FIGS. That is, in this embodiment, the upper surface in FIGS. 1 and 2 of the EA material 1 is an impact receiving surface, and the lower surface in FIGS. Hereinafter, the direction (or the opposite direction) from the impact receiving surface side to the back surface side of the EA material 1 is referred to as a thickness direction.

  In this embodiment, the EA material 1 has a large thickness portion 2 having a relatively large thickness and a small thickness portion 3 having a thickness smaller than that of the large thickness portion 2. As shown in FIGS. 1 and 2, the large thickness portion 2 and the small thickness portion 3 are disposed adjacent to each other in the direction orthogonal to the thickness direction. Hereinafter, for convenience, the adjacent direction of the large thickness portion 2 and the small thickness portion 3 is referred to as the longitudinal direction of the EA material 1, and the direction perpendicular to both the longitudinal direction and the thickness direction is referred to as the width direction of the EA material 1. Further, the side surfaces on both ends in the longitudinal direction of the EA material 1 and the side surfaces on both ends in the width direction are collectively referred to as a side peripheral surface of the EA material 1.

  As shown in FIGS. 1 and 2, the back surface of the large thickness portion 2 and the back surface of the small thickness portion 3 are substantially flush with each other, and the impact receiving surface of the small thickness portion 3 is the impact receiving surface of the large thickness portion 2. Rather than back to the back side. In other words, the impact receiving surface side from the middle portion in the thickness direction of the large thickness portion 2 has an overhang portion 4 that projects outward from the impact receiving surface of the small thickness portion 3 when the EA material 1 is attached to the door trim. It has become. The shape of the EA material 1 is not limited to this. For example, as shown in FIG. 6, the small thickness portion 3A may be arranged between the two large thickness portions 2A and 2A '.

  In this embodiment, the EA material 1 is divided into two parts, a first part 11 on the impact receiving surface side and a second part on the back side, and a first partial molding step and a second partial molding described later. The first part 11 and the second part 12 are sequentially foamed and molded by the process.

In this embodiment, in the EA material 1, the portion on the impact receiving surface side from the middle portion in the thickness direction of the large thickness portion 2 is constituted by the first portion 11, and the middle portion of the large thickness portion 2 in the thickness direction. The portion on the back side of the portion and the small thickness portion 3 are integrally formed by the second portion 12. The first portion 11 and second portion 12 are adjacent to each other, by the second portion forming step and the second partial synthetic resin material U ₂ into contact with the first portion 11, it is assumed that the bonded and integrated ing. Reference numeral 14 in FIGS. 1 and 2 represents a boundary portion between the first portion 11 and the second portion 12. In this embodiment, the boundary portion 14 is located at substantially the same level as the impact receiving surface of the small thickness portion 3. In other words, in the present embodiment, the first portion 11 substantially constitutes only the overhang portion 4. In addition, the fraction structure of the 1st part 11 and the 2nd part 12 is not limited to this.

  FIG. 3 shows the first part 11 before being integrated with the second part 12. In FIG. 3, the first portion 11 is drawn with a boundary surface 11 a (hereinafter simply referred to as a boundary surface) 11 a facing the second portion 12 facing upward.

  In this embodiment, the boundary surface 11 a of the first portion 11 is provided with a recess 11 b that is recessed toward the impact receiving surface side of the large thickness portion 2. The recess 11b is provided at a position separated from the outer peripheral edge of the boundary surface 11a toward the center of the boundary surface 11a. The outer peripheral side of the boundary surface 11a is closer to the back side of the thick portion 2 than the recess 11b. The bank-like portion 11c is raised one step further. The bank-like portion 11c is formed so as to surround the concave portion 11b along the outer peripheral edge of the boundary surface 11a.

In the second partial molding step, a part of the second part synthetic resin raw material U ₂ supplied into the cavity of the mold 20 is dispersed on the boundary surface 11 a of the first part 11. At this time, the second portion synthetic resin raw material U ₂ is formed between the side peripheral surface of the first portion 11 and the cavity inner surface of the mold 20 by the bank-shaped portion 11 c formed along the outer peripheral edge of the boundary surface 11 a. It is prevented or suppressed from entering, and accumulates in the recess 11b. In addition, the shape of the boundary surface 11a of the 1st part 11 is not limited to this.

<About the configuration of the mold 20>
In the mold 20 used in the second partial molding step, the internal shape of the cavity has a shape corresponding to the entire external shape of the EA material 1. As shown in FIGS. 4 and 5, in this embodiment, the mold 20 has a lower mold 21 and an upper mold 22. In addition, the metal mold | die 20 may have a core etc. as needed. In this embodiment, the EA material 1 is molded in the cavity of the mold 20 with its impact receiving surface facing downward. That is, the impact receiving surface of the EA material 1 is formed by the bottom surface of the cavity of the lower die 21, the side peripheral surface of the EA material 1 is formed by the peripheral surface of the cavity of the lower die 21, and the EA material is formed by the cavity ceiling surface of the upper die 22. The back surface of 1 is molded. In the cavity of the lower die 21, a large depth portion 23 corresponding to the large thickness portion 2 of the EA material 1 and a large depth portion 23 corresponding to the small thickness portion 3 of the EA material 1. A small depth portion 24 having a smaller depth is formed. In addition, the structure of the metal mold | die 20 is not limited to this, The EA material 1 may be shape | molded with the back surface (surface on the opposite side to an impact receiving surface) facing down.

  In the cavity of the mold 20, a space from the middle part in the depth direction of the large depth part 23 (a position substantially at the same level as the bottom surface of the small depth part 24) to the bottom surface of the large depth part 23 is EA. The space corresponding to the first portion 11 of the material 1 is a first portion corresponding space, and the remaining space in the cavity is a second portion corresponding space corresponding to the second portion 12 of the EA material 1.

<About the forming method of EA material 1>
In forming the EA material 1, a first partial molding process in which the first part 11 is foam-molded and a second partial molding process in which the second part 12 is foam-molded and integrated with the first part 11 are sequentially performed. To do. The first part synthetic resin raw material U ₁ for constituting the first part 11 and the second part synthetic resin raw material U ₂ for constituting the second part 12 may be of the same composition. The composition may be different. For example, when the second part synthetic resin raw material U ₂ is blended with a foamed synthetic resin having a lower hardness than the first partial synthetic resin raw material U ₁ , the back surface side has a lower hardness than the impact receiving surface side. Thus, the EA material 1 can be easily manufactured.

(1) About 1st partial shaping | molding process In a 1st partial shaping | molding process, the 1st part 11 is shape | molded alone. The molding of the first portion 11 can be performed by the same method as the molding of a general single foam molded article. That is, the molding of the first portion 11 is performed by using, for example, a mold (not shown) whose inner shape of the cavity corresponds to the outer shape of the first portion 11, and combining the first portion in the cavity. the resin material U ₁ can be performed by bubbling. In addition, the shaping | molding method of the 1st part 11 is not limited to this.

(2) About 2nd partial molding process In a 2nd partial molding process, first, it prepares beforehand by the 1st partial molding process in the back | inner side (1st part corresponding | compatible space) of the large depth part 23 in the cavity of the metal mold | die 20. The first portion 11 that has been prepared is inserted and arranged. Next, as shown in FIG. 4, the second part corresponding space in the cavity of the mold 20 (on the bottom surface of the small depth portion 24 and on the boundary surface 11a of the first part 11 disposed in the first part corresponding space) ) Is supplied with the second part synthetic resin raw material U ₂ , the upper mold 22 is put on the lower mold 21 and the mold is clamped, and then the second partial synthetic resin raw material U ₂ is foamed. As shown in FIG. 5, the second portion 12 is molded by filling the second portion corresponding space with the foamed synthetic resin obtained by foaming the second portion synthetic resin raw material U ₂ , and the entire EA material 1 is molded. Is completed. This since the second part for the synthetic resin raw material U ₂ is in contact with the boundary surface 11a of the first portion 11, second portion 12 of the second part for the synthetic resin raw material U ₂ is formed by foaming, the first portion 11 is bonded and integrated.

  After the foamed synthetic resin is cured, the lower die 21 and the upper die 22 are opened, the EA material 1 is removed, and then the EA material 1 is surface-finished as necessary, thereby the EA material 1 Is completed.

  The first portion 11 may be mass-produced in advance, and only the second partial molding process may be performed in an actual EA material production line, and the first portion 11 is foamed sequentially in one EA material production cycle. The molding and the foam molding of the second portion 12 may be performed sequentially.

  In the present invention, it is not easy to construct the entire impact-absorbing material with a uniform foamed synthetic resin in a single foam molding process, for example, a maximum thickness (a large thickness in the EA material 1 of this embodiment). The thickness of the part 2) is suitable for the production of an EA material having a thickness of 150 mm or more, particularly 200 mm or more.

[Second Embodiment]
FIG. 7 is a cross-sectional view of the EA material 1B according to the second embodiment, and FIGS. 8 and 9 each show a second partial molding die 20B (hereinafter referred to as a manufacturing method for the EA material 1B). , Simply referred to as a mold 20B). FIG. 7 is a cross-sectional view along the longitudinal direction and thickness direction of the EA material 1B, and FIGS. 8 and 9 show cross sections of portions corresponding to FIG. 7 of the mold 20B. Yes.

<About the configuration of the EA material 1B>
As shown in FIG. 7, the EA material 1B has a substantially trapezoidal cross section with a substantially uniform thickness as a whole. In this embodiment, the shock receiving surface side as a whole is constituted by the first portion 11B from the middle portion in the thickness direction of the EA material 1B, and the back side thereof as a whole is constituted by the second portion 12B. A boundary portion 14B between the first portion 11B and the second portion 12B extends substantially parallel to the impact receiving surface and the back surface of the EA material 1B. The configuration of the first portion 11B is substantially the same as that of the EA material 1 in the first embodiment described above except that the first portion 11B constitutes the entire impact receiving surface side of the EA material 1B. This is the same as the first portion 11. In addition, the fraction structure of the 1st part 11B and the 2nd part 12B is not limited to this.

  The other configuration of the EA material 1B is substantially the same as that of the EA material 1 in the first embodiment, and in FIGS. 7 to 9, the same reference numerals as those in FIGS. 1 to 5 denote the same parts.

<About the configuration of the mold 20B>
In the mold 20B used in the second partial molding step of the EA material 1B, the internal shape of the cavity is a shape corresponding to the entire outer shape of the EA material 1B. As shown in FIGS. 8 and 9, in this embodiment, the depth of the inside of the lower mold 21B of the mold 20B is substantially uniform as a whole. The space from the middle part in the depth direction in the cavity of the lower mold 21B to the bottom surface is a first part corresponding space corresponding to the first part 11B of the EA material 1B, and the upper side is the EA material. This is a second part corresponding space corresponding to the second part 12B of 1B.

  The other configuration of the mold 20B is substantially the same as that of the mold 20 in the first embodiment.

<About the forming method of the EA material 1B>
In forming the EA material 1B, a first partial molding step for foam-molding the first portion 11B and a second partial molding step for foam-molding the second portion 12B to integrate with the first portion 11B are sequentially performed. Do. The first portion 11B is molded as a single unit. The method for forming the first portion 11B is substantially the same as the method for forming the first portion 11 in the first embodiment, and a description thereof will be omitted.

(About the second partial molding process)
In the second partial molding step, first, the first portion 11B prepared in advance by the first partial molding step is inserted and arranged in the back side (first partial corresponding space) in the cavity of the lower mold 21B. Next, as shown in FIG. 8, the second part synthetic resin raw material U is placed in the second part corresponding space (on the boundary surface 11a of the first part 11B arranged in the first part corresponding space) in the cavity of the lower mold 21B. ₂ supplies, after clamping covered with a upper mold 22B on the lower die 21B, foaming the second portion for the synthetic resin raw material U _2. As FIG. 9, by foamed synthetic resin which the second part for the synthetic resin raw material U ₂ is formed by foaming fills the second portion corresponding space, it is the second portion 12B is molded, the entire EA member 1B Molding is complete. This since the second part for the synthetic resin raw material U ₂ is in contact with the boundary surface 11a of the first portion 11B, a second portion 12B of the synthetic resin raw material U ₂ for the second portion formed by foaming, the first portion 11B is bonded and integrated.

  Each of the above embodiments is an example of the present invention, and the present invention may have a configuration other than the above.

  For example, although the above embodiment shows an application example of the present invention to an EA material for automobile interior and a manufacturing method thereof, the present invention can be applied to other EA materials and a manufacturing method thereof. is there.

1, 1A, 1B EA material 2, 2A, 2A 'Large thickness portion 3, 3A Small thickness portion 4, 4A, 4A' Overhang portion 11, 11A, 11A ', 11B First portion 11a Interface 11b Recessed portion 11c Bank shape Part 12, 12A, 12B Second part 12a Boundary surface 12b Recess 12c Bank-like part 20, 20B Mold 21, 21B Lower mold 22, 22B Upper mold

Claims (7)

A method of producing a shock absorber by foaming a synthetic resin raw material with a mold,
The shock absorber has an impact receiving surface that receives an impact from a collision object, and a back surface opposite to the impact receiving surface.
The manufacturing method of the shock absorbing material includes the first to nth (n is an integer of 2 or more) in order from the shock receiving surface side to the back surface side or from the back surface side to the shock receiving surface side. 1) to n parts, and the first to nth parts are sequentially foam-molded.
In the first partial molding step, the first part is molded alone,
In the m-th (m is an integer of 2 to n) partial molding step, the m-th portion is formed in a state where the molded body molded in the (m-1) partial molding step is disposed in the cavity of the mold. Supplying the m-th part synthetic resin raw material to the inside of the cavity for foaming ,
A concave portion that is recessed toward the impact receiving surface side is provided at a boundary surface between the first portion and the second portion, and a bank-shaped portion that surrounds the concave portion over the entire circumference along the outer periphery of the boundary surface is provided. A method for producing an impact-absorbing material.   2. The method for producing an impact absorbing material according to claim 1, wherein the first to n-th parts are composed of synthetic resin raw materials having the same composition.   2. The production of an impact-absorbing material according to claim 1, wherein at least one portion of the first to n-th portions is composed of a synthetic resin raw material having a different composition from the synthetic resin raw material constituting the other portion. Method. 4. The shock absorber according to claim 1, wherein the shock absorber is a large-thickness portion having a relatively large thickness between the shock receiving surface and the back surface, and between the shock receiving surface and the back surface. Having a small thickness portion smaller than the large thickness portion,
The large thickness portion and the small thickness portion are adjacent to each other in the direction perpendicular to the thickness direction, and the portion on the side of the impact receiving surface from the middle portion in the thickness direction of the large thickness portion is the small thickness portion. It is an overhanging part projecting to the opposite side of the back side from the impact receiving surface of
Of the shock absorber, the overhanging portion is constituted by the first portion, and the back surface side portion of the overhanging portion is constituted by the second to nth portions. Production method.   5. The method for manufacturing an impact-absorbing material according to claim 1, wherein n = 2.   6. The method for manufacturing a shock absorber according to claim 1, wherein the shock absorber is a shock absorber for vehicle interior. The impact-absorbing material manufactured by the manufacturing method of the impact-absorbing material of any one of Claim 1 thru | or 6 .

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