JP4390689B2 - Shock absorber - Google Patents

Description

  The present invention relates to an impact absorbing material, and in particular, to absorb an impact applied to a heel of a front seat passenger of an automobile, the impact absorption provided between a partition between an engine room and a passenger compartment of the automobile and a vehicle floor mat. It relates to a material (referred to as a tibia pad).

  2. Description of the Related Art Conventionally, shock absorbers are disposed at various sites in automobiles. As the impact absorbing material, those made of rigid polyurethane foam, those made of a polyolefin-based resin with lattice-like ribs, bead resin molded bodies and the like are generally used. Other than these, there are a mixed chip molded body in which a mixture of a chip of a flexible polyurethane foam and a chip of a rigid polyurethane foam is bonded with a binder, and a molded product of a rigid polyurethane foam in a predetermined shape.

However, if a conventional shock absorber is used as the shock absorber for the heel, the reaction force at the time of impact is too high, and a large impact is applied to the heel of the occupant. If the amount is increased, there is a problem that the thickness of the entire shock absorber becomes too large and the leg space in the vehicle becomes narrow.
JP 2001-342284 A JP 2000-6741 A JP 2000-95048 A

  The present invention has been made in view of the above points, and provides a shock absorber for automobiles suitable for absorbing shock applied to the heel of a front seat passenger of the automobile.

According to the first aspect of the present invention, one side of a flat plate made of a soft foam made of a chip molded body in which chips of flexible polyurethane foam are bonded with a binder is used as an impact receiving surface, and is opposite to the impact receiving surface of the flat plate. On the back surface, a plurality of ribs made of hard closed cells are embedded substantially parallel to each other and protrude from the back surface of the flat plate on the leading end side of the rib, and the amount of compressive deformation when absorbing an impact of 27 J Is 15 to 23 mm, and the reaction force is 2500 N or less.

The invention of claim 2 is the invention according to claim 1, wherein the distance between the impact receiving surface of the flat plate and the embedded side end of the rib is 3 to 10 mm, and the overall height of the rib is 15 to 30 mm, The total thickness of the shock absorber is 18 to 40 mm .

  The inventor of the present invention relates to a shock absorber (tibia pad) provided between a partition wall between a vehicle engine room and a vehicle compartment and a vehicle floor mat. When the impact on the heel of the front seat occupant was examined, damage to the heel of the front seat occupant can be suppressed if the reaction force when the impact absorbing material absorbs the impact of 27J is less than 2500N. found. For this reason, according to the invention of claim 1, damage to the heel of the front seat occupant of the automobile can be suppressed. Also, if the amount of compressive deformation of the shock absorber when absorbing an impact of 27J is set to 15 to 23 mm, the shock absorber can be prevented from becoming extremely thick, and the leg space in the vehicle can be reduced. Enough can be secured.

Further , according to the invention of claim 1, one side of the flat plate is used as an impact receiving surface, and a plurality of ribs made of hard closed cells are embedded substantially parallel to each other on the back surface opposite to the impact receiving surface of the flat plate. By projecting from the back surface of the flat plate at the tip end of the rib, the shock received by the impact receiving surface of the flat plate is reliably transmitted to the rib made of hard closed cell on the back surface of the flat plate, and the rib is compressed and deformed. Can absorb the shock effectively. Moreover, since the hard closed cells constituting the ribs have a high shock absorption due to deformation as is well known, good shock absorption can be obtained. Furthermore, by adjusting the size of the rib, it is easy to make the reaction force when absorbing the impact of the energy amount 27J to 2500 N or less.

Further, in the invention of claim 1, the soft foam constituting the flat plate has a low impact absorption due to deformation as is well known. Therefore, according to the first aspect of the invention, almost all of the impact received on the impact receiving surface of the flat plate can be transmitted to the rib on the back surface of the flat plate, and the impact can be effectively absorbed by compressive deformation of the rib. By adjusting the rib size, the reaction force at the time of impact can be easily reduced to 2500 N or less.

According to the invention of claim 2 , the distance between the impact receiving surface of the flat plate and the embedded side end of the rib is 3 to 10 mm, and the overall height of the rib (the total of the embedded amount and the protruding height) is When the thickness of the shock absorber is 15 to 30 mm and the thickness of the shock absorber is 18 to 40 mm, not only the shock absorption by the rib can be improved, but also the thickness of the shock absorber is extremely increased. Can be prevented, and sufficient leg space in the vehicle can be secured.

  Hereinafter, embodiments of the present invention will be described in detail. FIG. 1 is a perspective view of a shock absorber according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along the line 2-2 of FIG.

  The shock absorber 10 shown in FIGS. 1 and 2 is provided between the partition between the engine room and the vehicle compartment of the automobile and the vehicle floor mat in order to absorb the impact applied to the heel of the front passenger of the automobile. The amount of compressive deformation when absorbing an impact with an energy amount of 27 J is 15 to 23 mm, the reaction force is 2500 N or less, and is configured by the flat plate 11 and the rib 15. If the amount of compressive deformation when absorbing an impact of 27 J is less than 15 mm, the reaction force is likely to be larger than the prescribed 2500 N, whereas if the amount of compressive deformation is greater than 23 mm. The problem that the amount of compressive deformation of the shock absorbing material becomes long is likely to occur. Moreover, if the reaction force exceeds 2500 N, there is a high possibility that the heel of the passenger will be damaged.

The flat plate 11 is made of a soft foam, and one side is an impact receiving surface 11a to which an impact is applied, and a rib 15 is embedded in a back surface 11b opposite to the impact receiving surface 11a. As the soft foam, a chip molded body in which chips of soft polyurethane foam are bonded with a binder is preferable from the viewpoint of manufacturing workability. More preferably, it is a chip molded body molded with the rib 15 as an insert. Specifically, the flat plate 11 made of the chip molded body of the flexible polyurethane foam has the required number of ribs 15 set in the mold cavity formed according to the shape of the shock absorber 10, and then the flexible polyurethane foam. The mixture of the chip and the binder is filled in the cavity, the mold is closed, and the binder is cured by heating or the like, and the impact absorbing material 10 is thereby obtained. The size of the chip is appropriately selected, but those having an average particle diameter of 3 to 15 mm are usually used. What is used for shaping | molding of a well-known chip molded article can be used for a binder. For example, moisture-curing urethane prepolymer or crude methylene diphenyl diisocyanate (crude MDI) can be used.

The distance b between the impact receiving surface 11a of the flat plate 11 and the embedded end of the rib 15 is preferably 3 to 10 mm. If the distance b between the impact receiving surface 11a and the embedded end of the rib 15 is less than 3 mm, it is difficult to hold the rib 15 correctly, for example, the rib 15 may be inclined in a normal state. On the other hand, when the value of b exceeds 10 mm and the ratio of the distance b between the impact receiving surface 11a and the embedded side end of the rib 15 with respect to the total thickness a of the shock absorber 10 increases, Therefore, it is difficult to control the reaction force at the time of absorbing the impact by the size of the rib 15 and the like. Become. In addition, as for the density of the flat plate 11 which consists of the said chip molded object, 40-400 kg / m < ³ > is preferable. In the case of less than 40 kg / m ³ , when the chip molded body is molded, there is a possibility that defective filling of the chip into the mold may occur, and the chip molded body may be thinned. On the other hand, if it exceeds 400 kg / m ³ When trying to form the flat plate 11 by chip molding using the rib 15 as an insert, the rib 15 may be deformed.

  The rib 15 is composed of a block of elongated hard closed cells, and a plurality of ribs 15 are made substantially parallel to each other on the back surface 11b of the flat plate 11 and embedded on the base side 15a, and protrude from the back surface 11b of the flat plate 11 on the tip side 15b. Yes. The rib 15 is prevented from being separated from the flat plate 11 by being embedded. The shape of the rib 15 in the present embodiment is a square bar shape having a rectangular cross section. The closed cell refers to a composition having a closed cell rate of 30% or more determined in accordance with ASTM D 2856. Furthermore, those having a closed cell ratio of 50% or more are more preferable as the hard closed cell body constituting the rib 15. As the hard closed cells constituting the ribs 15, suitable hard closed cells are used, and in particular, a hard polyurethane foam is preferable from the viewpoint of impact absorption and the like.

  The rib 15 is embedded in the flat plate 11 with the thickness direction of the shock absorber 10 being the height direction of the rib 15. The overall height c of the rib 15 (the total height of the burying amount e in the flat plate 11 and the protruding height d from the flat plate 11) c is preferably 15 to 30 mm. When it is less than 15 mm, the shock absorption of the rib 15 is inferior, and when it exceeds 30 mm, the thickness a of the shock absorber 10 becomes large and the leg space in the vehicle becomes narrow. The width w of the rib 15 is determined in relation to the interval u between the ribs 15. That is, when the width w of the rib 15 is small, good shock absorption cannot be obtained unless the number of the ribs 15 is increased. Therefore, the interval u between the ribs 15 is also reduced. If it is large, the reaction force of the shock absorbing material 10 becomes large. Therefore, since the number of ribs 15 needs to be reduced in order to make it equal to or less than the predetermined reaction force, the interval u between the ribs 15 also becomes large. In order to obtain a constant shock absorbency even if the impact position is different on the impact receiving surface 11a, the dimensions such as the width and the height of each of the ribs 15 should be substantially equal, and the intervals should be uniform. preferable

The hard closed cells used as the ribs 15 preferably have a density of 35 to 100 kg / m ³ . The embedding amount e of the ribs 15 in the flat plate 11 is set to a depth at which the ribs 15 can be correctly held on the flat plate 11 in normal times, and is usually 3 to 5 mm. Moreover, although the protrusion height d from the flat plate 11 of the said rib 15 is made appropriate, 15-27 mm is preferable when the thickness a of the impact-absorbing material 10 whole is considered. The thickness a of the entire shock absorber 10 is preferably 18 to 40 mm in consideration of a preferable overall height 15 to 30 mm of the rib 15 and a leg space in the vehicle.

Examples of the present invention will be specifically described. The shock absorbers of Examples 1 to 4 and Comparative Examples 1 and 2 shown in Table 1 were prepared. The structure of the impact absorbing material in Examples 1 to 4 and Comparative Examples 1 and 2 is the same as the structure shown in FIG. The flat plate is composed of a chip molded body formed from a chip mixture in which a wet heat curable binder (product name: KF-1 manufactured by Inoac Corporation) is mixed at a weight ratio of 20:80 to a chip of flexible polyurethane foam, and the density is 80 kg / m is ^3. The rib is made of a rigid polyurethane foam having a density of 45 kg / m ³ and a hardness of 25 N / cm ² , and the flat plate and the rib are integrated by chip molding of the flat plate using the rib as an insert.

A test piece sample having a plane size of 150 × 150 mm was cut out from Examples 1 to 4 and Comparative Examples 1 and 2, and an impact surface area of 65.92 cm ² and a weight of 8. The impactor (compressive stress) and the amount of compressive deformation (deflection) at that time are collided with a collision of 5 kg at a speed of 3.5 m / sec, and the compressive deformation when the impact absorption energy reaches 27J. The quantity and reaction force (compressive stress) were measured. The results are as shown in the lower part of Table 1. In each of Examples 1 to 4, the amount of compressive deformation when absorbing an impact with an energy amount of 27 J is 15 to 23 mm and the reaction force is 2500 N or less, whereas in Comparative Example 1, the total height of the ribs is Since it is as low as 13 mm, the reaction force is very high at 3400 N due to the bottom of the rib during impact, and the impact applied to the heel of the occupant increases. In Comparative Example 2, the amount of compressive deformation when absorbing an impact with an energy amount of 27 J is as large as 30 mm and the thickness of the shock absorber is large, so the leg space in the vehicle is narrowed.

1 is a perspective view of a sound absorbing shock absorber according to an embodiment of the present invention. It is 2-2 sectional drawing of FIG.

DESCRIPTION OF SYMBOLS 10 Shock absorber 11 Flat plate 11a Flat plate impact receiving surface 11b Flat plate rear surface 15 Rib 15a Rib base side 15b Rib tip side

Claims (2)

One side of a flat plate (11) made of a soft foam made of a chip molded body in which chips of flexible polyurethane foam are bonded with a binder is used as an impact receiving surface (11a), and the impact receiving surface (11a) in the flat plate (11) is formed. A plurality of ribs (15) made of hard closed cells are embedded substantially parallel to each other on the back surface (11b) opposite to), and project from the back surface (11b) of the flat plate on the tip side (15b) of the ribs An impact-absorbing material comprising a structure, having an amount of compressive deformation of 15 to 23 mm when absorbing an impact with an energy amount of 27 J, and a reaction force of 2500 N or less. The distance between the flat impact receiving surface (11a) and the embedded side end of the rib (15) is 3 to 10 mm, the overall height of the rib (15) is 15 to 30 mm, and the shock absorption The shock absorber according to claim 1, wherein the entire thickness of the material (10) is 18 to 40 mm .

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