Knee Bolster

Abstract

To provide a knee bolster which can deal with a wider range of magnitudes of impacts than conventional knee bolsters.SOLUTION: In a knee bolster 10 of the disclosure, a rigid polyurethane foam 40, which receives a pressing force from a knee H to cause compression failure, and an energy absorption rib 12, which receives the pressing force to buckle after the compression failure of the rigid polyurethane foam 40 proceeds, are provided arranged side by side in a direction that the knee bolster 10 receives the pressing force. Further, the rigid polyurethane foam 40 is housed in a container 11 divided into first and second container split bodies 20, 30 and the energy absorption rib 12 is integrally formed with the second container split body 30.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a knee bolster that receives the knees of an occupant during a vehicle collision and reduces the impact to the knees. [Background technology]

[0002] A known conventional knee bolster absorbs shock by compressive failure of rigid polyurethane foam (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2003-327066 A (paragraphs

[0017] ,

[0018] , Figure 1, etc.) Summary of the Invention [Problem to be solved by the invention]

[0004] The magnitude of the impact that the knee bolster receives from the knees of the occupant varies greatly depending on, for example, whether or not a seat belt is fastened, the seating position of the occupant, etc. For this reason, there is a demand for the development of a knee bolster that can handle a wider range of impact magnitudes than before. [Means for solving the problem]

[0005] A first aspect of the invention made to solve the above problems is a knee bolster that supports the knees of an occupant in the event of a vehicle collision, the knee bolster comprising: a rigid polyurethane foam that compressively breaks when subjected to a pressing force from the knee; and an energy absorbing rib that buckles after the rigid polyurethane foam has undergone compressive failure when subjected to the pressing force, the bolster being arranged in a first direction, which is the direction in which the pressing force is received.

[0006] A second aspect of the present invention is the knee bolster according to the first aspect, comprising a pair of opposing members facing each other in the first direction with the rigid polyurethane foam therebetween, and stopper portions provided on the pair of opposing members that approach and come into contact with each other as the rigid polyurethane foam undergoes compressive failure, thereby maintaining the progress of the compressive failure of the rigid polyurethane foam at a constant amount, and buckling of the energy absorbing rib begins after the stopper portions come into contact with each other.

[0007] A third aspect of the present invention is a knee bolster according to the first or second aspect, comprising a pair of container sections that are formed by dividing a container that contains the rigid polyurethane foam in the first direction, engage with each other so as to restrict movement in a direction intersecting the first direction, and whose fitting with each other deepens as the rigid polyurethane foam is compressed and destroyed, and the energy absorbing rib is arranged on the outer surface of the container sections.

[0008] A fourth aspect of the present invention is the knee bolster according to the third aspect, wherein the pair of container sections have a box-like structure with openings on opposing sides.

[0009] A fifth aspect of the present invention is the knee bolster according to the third or fourth aspect, wherein the one container section and the energy absorbing rib are integrally molded from resin.

[0010] A sixth aspect of the present invention is a knee bolster as claimed in any one of the third to fifth aspects, wherein the energy absorbing rib is in a lattice shape having a plurality of squares, and a reinforcing rib extending along the diagonal line of the squares of the energy absorbing rib is provided on the back surface of the surface of one of the container sections that has the energy absorbing rib.

[0011] A seventh aspect of the present invention is a knee bolster as claimed in any one of the third to sixth aspects, wherein the rib support wall of one of the container sections that is provided with the energy absorbing rib has an elongated shape, the energy absorbing rib is in a lattice pattern having a plurality of square cells, the size of the rib support wall in the short side direction is approximately an integer multiple of the diagonals of the cells, a pair of diagonals of each of the cells are arranged parallel to the longitudinal direction and short side directions of the rib support wall, and the diagonals of the cells are arranged to overlap with a center line of the rib support wall in the short side direction.

[0012] An eighth aspect of the present invention is a knee bolster as claimed in any one of the first to sixth aspects, wherein the rigid polyurethane foam has an elongated shape when viewed from the first direction, and the energy absorbing rib has a lattice shape having a plurality of square cells, and a pair of diagonals of each of the cells are arranged parallel to the longitudinal and lateral directions of the elongated shape. Effect of the Invention

[0013] The knee bolster of the first embodiment of the present invention comprises a rigid polyurethane foam and an energy absorbing rib, and when it receives pressure from the occupant's knees, the rigid polyurethane foam compressively breaks, and then the energy absorbing rib compressively breaks (buckles). Therefore, in addition to the range of impact magnitude that could be handled by conventional knee bolsters, which absorbed impact from the knees using only rigid polyurethane foam, it can also handle larger impacts, broadening the range of impact magnitude that can be handled compared to conventional knee bolsters.

[0014] Here, in order to prevent the energy absorbing rib from digging into the rigid polyurethane foam, for example, a portion of the rigid polyurethane foam may be impregnated with non-foamed rigid urethane, or a plate member may be provided between the energy absorbing rib and the rigid polyurethane foam.

[0015] Furthermore, as in the second aspect of the present invention, by providing a pair of opposing members facing each other in a first direction with the rigid polyurethane foam between them, and providing the opposing members with stopper portions that approach and come into contact with each other as the rigid polyurethane foam undergoes compressive failure, thereby maintaining the progress of the compressive failure of the rigid polyurethane foam at a constant amount, the timing at which the energy absorbing rib begins to buckle and the amount of compressive failure of the rigid polyurethane foam at that time can be stabilized.

[0016] According to the knee bolster of the third aspect of the present invention, even if the rigid polyurethane foam is sheared obliquely against the direction of pressure due to the pressure applied, the pair of container halves that contain the rigid polyurethane foam engage with each other to suppress the progress of shearing and allow the rigid polyurethane foam to undergo compressive failure. This stabilizes the amount of compressive failure of the rigid polyurethane foam against the pressure, and stabilizes the amount of shock absorption.

[0017] Here, the pair of container sections may be such that only one container section is a box with an opening at one end, and the other container section is a lid that closes the opening of the box section and fits inside the box section, or may have a box-shaped structure with openings on opposing sides as in the fourth embodiment of the present invention. When both container sections are box-shaped, they may approach each other as the rigid polyurethane foam is compressed and destroyed, and the edges of the openings of the container sections may come into contact with each other, or the edge of the opening of one container section may enter the inside of the other container section and come into contact with the inner surface of the other container section. Furthermore, the pair of container sections may be engaged with each other to "restrict movement in a direction intersecting the first direction," or, for example, multiple protrusions protruding in the first direction from one of the pair of container sections may be inserted into multiple engagement holes in the other container section to engage with each other as described above.

[0018] Furthermore, one of the container sections and the energy absorbing rib may be integrally molded from resin (fifth embodiment of the present invention), or may be separate bodies.

[0019] The energy absorbing rib may have any structure so long as it protrudes in a first direction and buckles under pressure, and may have, for example, a cross-sectional shape, a cylindrical shape, an elliptical cylindrical shape, a honeycomb shape, or may have a lattice shape having multiple squares as in the sixth and seventh embodiments of the present invention.

[0020] In addition, a reinforcing rib may be provided on the back side of the surface of the container section that has the energy absorbing rib for reinforcement. For example, as in the sixth embodiment of the present invention, the reinforcing rib can be provided at a position that extends along the diagonal line of the energy absorbing rib square to provide well-balanced reinforcement.

[0021] Furthermore, when a lattice-shaped energy absorbing rib having a plurality of square cells is provided on the elongated rib support wall of the container section, by making the size of the rib support wall in the short side direction approximately an integer multiple of the diagonals of the cells, arranging a pair of diagonals of each cell parallel to the longitudinal and lateral directions of the rib support wall, and arranging the diagonals of the cells overlapping with the center line of the short side of the rib support wall as in the seventh aspect of the present invention, it is possible to increase the number of intersections between cells surrounded by energy absorbing ribs connected on the diagonals of the cells while ensuring the required cell size, compared to a configuration in which the length and width of each cell are arranged parallel to the longitudinal and lateral directions of the rib support wall. This prevents the energy absorbing rib from being pushed down without buckling, and stabilizes the timing at which the energy absorbing rib starts to buckle. [Brief description of the drawings]

[0022] [Figure 1] FIG. 1 is a cross-sectional view of a portion of a vehicle to which a knee bolster according to a first embodiment is attached; [Diagram 2] Plan view of knee bolster installed on vehicle [Diagram 3] Knee bolster cross section [Figure 4] A perspective view of the knee bolster from the front [Diagram 5] Exploded perspective view of knee bolster [Figure 6] A perspective view of the knee bolster from the rear side [Figure 7]A graph conceptually showing the relationship between the load from the knee and the deformation of the knee bolster. [Figure 8] (A) Cross-sectional view of the knee bolster, (B) Cross-sectional view of the knee bolster when the rigid polyurethane foam is compressed, (C) Cross-sectional view of the knee bolster when the energy absorbing rib is buckled [Figure 9] FIG. 2 shows (A) a planar cross-sectional view of a knee bolster according to a second embodiment, and (B) a planar cross-sectional view of the knee bolster when the rigid polyurethane foam is compressed. [Figure 10] Exploded perspective view according to a third embodiment [Figure 11] A perspective view of the knee bolster from the rear side [Figure 12] A perspective view of a knee bolster in which rigid polyurethane foam has been crushed by compression [Figure 13] FIG. 13 is a perspective view of a knee bolster according to another embodiment, as viewed from the rear side; [Figure 14] FIG. 11 is a cross-sectional plan view of a knee bolster according to another embodiment of the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] [First embodiment] A first embodiment of a knee bolster 10 of the present disclosure will be described with reference to Figures 1 to 8. As shown in Figures 1 and 2, the knee bolster 10 of this embodiment is attached to a pair of pedestal portions 95 provided on a reinforcement 92 extending in the vehicle width direction behind an instrument panel 91 of a vehicle 90. Each pedestal portion 95 is formed, for example, by fixing a support plate 94 to the tips of a pair of ribs 93 that protrude diagonally rearward and downward from the reinforcement 92. The support plate 94 has, for example, a vertically long rectangular shape and has a mounting surface 94A facing diagonally rearward and downward.

[0024] The knee bolsters 10 are attached to the mounting surfaces 94A of the pair of pedestal portions 95 in an overlapping manner, and are disposed in a position diagonally above and in front of both knees H of the driver, i.e., occupant J. When the vehicle 90 collides and the lower portions of both legs of the occupant J rotate forward with the heels as the fulcrum, and the knees H move diagonally above and in front of the instrument panel 91 and bite into the instrument panel 91, each knee bolster 10 is pressed against each knee H through the instrument panel 91 and is compressed and broken, absorbing the impact on the knees H.

[0025] The direction in which the mounting surface 94A of each pedestal portion 95 faces (i.e., the normal direction of the mounting surface 94A) is set to coincide with the movement direction of the knee H of an occupant J of an assumed average build. In the following description of the knee bolster 10, the aforementioned assumed movement direction of the knee H is referred to as the "first direction A1," the side of the knee bolster 10 that is attached to the pedestal portion 95 is referred to as the "rear side," and the opposite side is referred to as the "front side." In addition, the diagonal upward and downward direction perpendicular to the first direction A1 is referred to as the "vertical direction," and the direction perpendicular to the vertical direction and the first direction A1 is referred to as the "horizontal direction."

[0026] As shown in Fig. 3, the knee bolster 10 includes a rigid polyurethane foam 40 housed in a container 11. As shown in Fig. 4, the container 11 has a generally vertically elongated rectangular parallelepiped shape as a whole, and is divided into first and second container sections 20, 30 at a generally central position in the first direction A1. The first and second container sections 20, 30 are injection-molded products of a resin such as polypropylene, and as shown in Fig. 3, have a box-like structure with openings on opposing sides, and have bottom walls 21, 31 and side walls 22, 32 standing up from the outer edges of the bottom walls 21, 31.

[0027] Moreover, the side wall 32 of the second container section 30 on the rear side stands approximately perpendicular to the bottom wall 31, whereas the side wall 22 of the first container section 20 on the front side is inclined relative to the bottom wall 21 so as to expand outward as it moves away from the bottom wall 21. The side wall 32 of the second container section 30 fits inside the side wall 22 of the first container section 20, and rigid polyurethane foam 40 is sandwiched between the bottom walls 21, 31 of the first and second container sections 20, 30, so that the first and second container sections 20, 30 are positioned where only the tips of the side walls 22, 32 fit together.

[0028] Then, the rigid polyurethane foam 40 is pressed by the bottom walls 21, 31 and is compressed and destroyed, and the progress of the compressive destruction stops when the tip of the side wall 32 of the second container section 30 abuts against the bottom wall 21 of the first container section 20. That is, in this embodiment, the above-mentioned bottom walls 21, 31 correspond to the "pair of opposing members" in the claims, and the side wall 32 and the bottom wall 21 correspond to the "stopper portion" in the claims.

[0029] Locking protrusions 23, 33 are provided at the tips of the side walls 22, 32 of the first and second container sections 20, 30. The locking protrusions 23, 33 each have a right-angled triangular cross section, extend along the tip edges of the side walls 22, 32, and have a locking surface perpendicular to the first direction A1. The locking protrusion 23 of the first container section 20 protrudes inward from the side wall 22, while the locking protrusion 33 of the second container section 30 protrudes outward from the side wall 32. The locking surfaces of the locking protrusions 23, 33 face each other to prevent the first and second container sections 20, 30 from separating.

[0030] 5, reinforcing ribs 34 are formed on the inner surface of the bottom wall 31 of the second container section 30. The reinforcing ribs 34 are, for example, in a lattice shape and include a vertical rib 34T that extends straight in the vertical direction at the horizontal center of the bottom wall 31, and a plurality of horizontal ribs 34Y that extend horizontally at a plurality of positions in the vertical direction of the bottom wall 31. Furthermore, cylindrical ribs 34E are formed at every other intersection of the vertical ribs 34T and the horizontal ribs 34Y, and through-holes 34F are formed in the center of the cylindrical ribs 34E.

[0031] In this embodiment, the first and second container sections 20, 30 are prevented from separating by the locking protrusions 23, 33. However, for example, a member protruding from one of the side walls 22, 32 of the first and second container sections 20, 30 toward the other may be engaged with a hole formed in the other to prevent separation of the first and second container sections 20, 30, or the bottom walls 21, 31 of the first and second container sections 20, 30 may be fixed to the rigid polyurethane foam 40 with an adhesive or the like to prevent separation of the first and second container sections 20, 30.

[0032] As shown in Fig. 5, the rigid polyurethane foam 40 is a foam-molded product having a substantially rectangular parallelepiped shape. As shown in Fig. 3, approximately half of the back side of the rigid polyurethane foam 40 fits exactly inside the second container section 30, and approximately half of the front side fits inside the first container section 20, and a gap is provided between the side wall 22 of the first container section 20 and the rigid polyurethane foam 40 so that the side wall 32 of the second container section 30 can move. As shown in Fig. 5, a groove 40M for receiving the reinforcing rib 34 is formed on the back side of the rigid polyurethane foam 40. The side surfaces of the rigid polyurethane foam 40 are slightly inclined outward from both ends in the first direction A1 toward the center.

[0033] The bottom wall 31 of the second container section 30 corresponds to a "rib supporting wall" in the claims, and an energy absorbing rib 12 is integrally formed on the outer surface of the bottom wall 31. The energy absorbing rib 12 is perpendicular to the outer surface of the bottom wall 31, and the amount of protrusion from the bottom wall 31 is, for example, 1 to 2 times the thickness of the rigid polyurethane foam 40 in the first direction A1, as shown in Fig. 3 .

[0034] 6, the energy absorbing rib 12 includes a plurality of first ribs 13A and a plurality of second ribs 13B inclined at an angle of 45 degrees with respect to both the vertical and horizontal directions of the bottom wall 31 and perpendicular to each other, and a plurality of square cells 14 surrounded on all four sides by the first ribs 13A and the second ribs 13B are arranged in the vertical direction of the bottom wall 31. In detail, the energy absorbing rib 12 is formed so that the length of the diagonal line of the cells 14 is approximately equal to an odd multiple (for example, 1 in this embodiment) of the length of the diagonal line of the cells 14 and the length in the short side direction (i.e., the horizontal direction) of the bottom wall 31. The diagonal lines of the cells 14 are arranged so as to overlap with the center line of the short side direction of the bottom wall 31. With this configuration, compared to a configuration in which the vertical and horizontal sides of each square 14 are arranged parallel to the longitudinal and lateral directions of the bottom wall 31, it is possible to increase the number of intersections between squares 14 surrounded by energy absorbing ribs 12 that are connected to the diagonals of the squares 14 relative to the bottom wall 31 while maintaining the size of the squares 14. In this embodiment, the length of the longitudinal direction (i.e., the vertical direction) of the bottom wall 31 is, for example, two or more times and less than three times the length of the diagonal of the squares 14, and the shapes of the energy absorbing ribs 12 at both ends of the longitudinal direction of the bottom wall 31 are symmetrical.

[0035] Further, the multiple horizontal ribs 34Y (see FIG. 5) of the reinforcing rib 34 described above are arranged in the longitudinal direction of the bottom wall 31 at a pitch that is 1 / 2 the pitch of the diagonals of the squares 14 of the energy absorbing rib 12, and are arranged so as to overlap with the horizontal diagonals of the squares 14. Furthermore, the vertical rib 34T of the reinforcing rib 34 is located in the horizontal center of the bottom wall 31 as described above, and is arranged so as to overlap with the vertical diagonals of the squares 14. Thus, in this embodiment, the reinforcing ribs 34 are arranged along the diagonals of the squares 14 of the energy absorbing rib 12, so that the bottom wall 31 is reinforced in a well-balanced manner. Furthermore, the aforementioned multiple through holes 34F are arranged at a rib intersection 13C where the first rib 13A and the second rib 13B cross at the horizontal center of the bottom wall 31 in the energy absorbing rib 12, and the end of the rib intersection 13C on the bottom wall 31 side is cut away to form a notch 15 so as to extend the through holes 34F. This prevents deformation of the bottom wall 31 due to sink marks during molding.

[0036] 4, mounting pieces 17 protrude laterally from the four corners of the front end of the entire energy absorbing rib 12. Then, bolts passed through through holes 17K that pass through these mounting pieces 17 are fastened to screw holes (not shown) provided in the four corners of the mounting surface 94A of the base portion 95, thereby fixing the knee bolster 10 to the base portion 95. Note that the mounting pieces 17 are omitted in the figures other than FIG. 4.

[0037] The energy absorbing rib 12 has a strength such that it is compressed and broken (specifically, buckled) after the rigid polyurethane foam 40 is compressed and broken when the knee bolster 10 is pressed in the first direction A1. Specifically, the compressive strength of the rigid polyurethane foam 40 is, for example, 3 to 4 kgf / cm 2 The buckling strength of the energy absorbing rib 12 is, for example, 6 to 7 kgf / cm 2 Here, assuming that the area of ​​the inner surface of the bottom wall 31 of the second container section 30 is the pressing area, the compression of the knee bolster 10 applies a pressing force of approximately 3 to 4 kgf / cm to the pressing area from the start to the end of the compression collapse of the rigid polyurethane foam 40. 2 During this time, a first reaction force F1 of the same magnitude as the first pressing force is returned to the pressing side. After the compression and destruction of the rigid polyurethane foam 40 is completed, the compression of the knee bolster 10 requires a first pressing force of approximately 6 to 7 kgf / cm2 on the pressing area. 2 During this time, a second reaction force F2 of the same magnitude as the second pressing force is returned to the pressing side.

[0038] 7 is a graph showing the relationship between the compression amount L of the knee bolster 10 when the knee bolster 10 is pressed and the reaction force F from the knee bolster 10. In the graph, the period when the compression amount L changes from 0 to a corresponds to the elastic deformation of the rigid polyurethane foam 40, the period when it changes from a to b corresponds to the compressive failure of the rigid polyurethane foam 40, the period when it changes from b to c corresponds to the elastic deformation of the energy absorbing rib 12, and the period when it changes from c to d corresponds to the compressive failure of the energy absorbing rib 12.

[0039] The structure of the knee bolster 10 of this embodiment has been described above. Next, the action and effect of the knee bolster 10 will be described. When the vehicle 90 collides, for example, the occupant J, who is the driver, moves forward from the driver's seat due to inertial force, and the part of the occupant J above the legs is received by the airbag. Meanwhile, the legs of the occupant J rotate around the heel as a fulcrum, and the knees H move diagonally forward and upward, pressing against the instrument panel 91, and as shown in FIG. 8, the knee bolster 10 on the back side of the instrument panel 91 receives the pressing force from the knees H. Then, the knee bolster 10 is compressed and broken, absorbing the kinetic energy due to the inertial force of the occupant J and mitigating the impact on the knees H.

[0040] At this time, the kinetic energy due to the inertial force that the knee bolster 10 receives from the occupant J differs greatly depending on whether or not the occupant J is fastening a seat belt. If the occupant J is below the assumed maximum weight and is fastening a seat belt, the kinetic energy due to the inertial force of the occupant J is absorbed by the compressive failure of only the rigid polyurethane foam 40 of the knee bolster 10, whereas if the occupant J is not fastening a seat belt, the kinetic energy due to the inertial force of the occupant J is absorbed by the compressive failure of only the rigid polyurethane foam 40 of the knee bolster 10 and the subsequent compressive failure of the energy absorbing rib 12.

[0041] Specifically, when the instrument panel 91 is pressed by the knee H and deformed, it comes into contact with the bottom wall 21 of the first container section 20 of the knee bolster 10, and the first container section 20 moves to deepen the engagement with the second container section 30, and the entire rigid polyurethane foam 40 is pressed in the first direction A1 between the bottom walls 21, 31 of the first and second container sections 20, 30. As a result, the entire rigid polyurethane foam 40 is subjected to a pressing force in the first direction A1 and is compressed and destroyed. At that time, even if the pressing force acts as a shear force inclined with respect to the first direction A1 and the rigid polyurethane foam 40 is sheared, the first and second container sections 20, 30 surround the rigid polyurethane foam 40 from the sides and are engaged (fitted) so that the first and second container sections 20, 30 do not move sideways relative to each other, so that the progress of the shear is suppressed and the compressive destruction progresses. As a result, the amount of compressive failure of the rigid polyurethane foam 40 against the pressing force is stabilized, the amount of shock absorption is stabilized, and the reaction force F applied to the knee H from the knee bolster 10 is also stabilized. Then, before the entire rigid polyurethane foam 40 is completely compressed and destroyed, the side wall 32 of the second container section 30 abuts against the bottom wall 21 of the first container section 20, as shown in FIG. 8(B), and the compressive failure of the rigid polyurethane foam 40 ends when the side walls 32 and the bottom wall 21 of the first and second container sections 20, 30 abut against each other. As a result, the amount of compressive failure of the rigid polyurethane foam 40 is stabilized, and the timing at which the energy absorbing ribs 12 start to buckle, which will be described next, is also stabilized.

[0042] If the occupant J is wearing a seat belt, the movement of the knees H stops before the compression failure of the rigid polyurethane foam 40 is completed. If the occupant J is not wearing a seat belt, the knees H continue to move even after the compression failure of the rigid polyurethane foam 40 is completed, and the knee bolster 10 is further pressed, the pressure increases, and the energy absorbing rib 12 begins to compress (specifically, buckle) (see FIG. 8(C)). Here, the energy absorbing ribs 12 are arranged so that the number of intersections between the cells 14 surrounded by the energy absorbing ribs 12 connected diagonally to the cells 14 increases by being inclined with respect to the length and width of the bottom wall 31 of the second container section 30 that supports the energy absorbing ribs 12, so that the energy absorbing ribs 12 are prevented from being pushed down without buckling, and the amount of impact absorption due to the buckling of the energy absorbing ribs 12 is stabilized. Even if the occupant J is not wearing a seat belt, the movement of the knees H stops due to the effect of the airbag before the compression failure of the energy absorbing ribs 12 is completed.

[0043] As described above, the knee bolster 10 of this embodiment includes the rigid polyurethane foam 40 and the energy absorbing rib 12, and the rigid polyurethane foam 40 compresses and breaks when pressed by the knee H of the occupant J, and then the energy absorbing rib 12 compresses and breaks (buckles), so that in addition to the range of impact magnitude that can be handled by conventional knee bolsters that absorbed impact from the knee H only by the rigid polyurethane foam 40, it can also handle larger impacts, thereby widening the range of impact magnitude that can be handled. Also, if the knee bolster 10 of this embodiment is set to absorb impacts within the range that can be handled by the conventional knee bolster 10 by the compressive failure of only the rigid polyurethane foam 40, an increase in the reaction force from the knee bolster 10 to the knee H that accompanies an increase in the range that can be handled can be suppressed.

[0044] [Second embodiment] The knee bolster 10V of this embodiment is shown in Figure 9. In the knee bolster 10V of this embodiment, the first container section 20V is box-shaped with an opening on the side of the second container section 30V, while the second container section 30V is a plate-like lid that closes the opening of the first container section 20V. In addition, the bottom wall 21V of the first container section 20V and the second container section 30V are fixed to the rigid polyurethane foam 40V with, for example, an adhesive.

[0045] A plurality of through holes 41 (only one through hole 41 is shown in FIG. 9) are formed in the horizontal center of the rigid polyurethane foam 40V, penetrating through a plurality of positions in the vertical direction in the first direction A1. A plurality of cylindrical stopper portions 24A protruding from the bottom wall 21V of the first container section 20V and a plurality of cylindrical stopper portions 24B protruding from the second container section 30V are fitted into both ends of the plurality of through holes 41 in the rigid polyurethane foam 40V. Other than as described above, the configuration of the knee bolster 10V of this embodiment is the same as that of the knee bolster 10 of the first embodiment.

[0046] The configuration of this embodiment also provides the same effects as those of the first embodiment. In addition, in this embodiment, when the rigid polyurethane foam 40V is compressed and destroyed, the tips of the stopper portions 24A and 24B come into contact with each other as shown in Fig. 9(B), and the compressive destruction of the rigid polyurethane foam 40V ends.

[0047] The locking projection 23 (see FIG. 3) described in the first embodiment may be provided at the tip of the side wall 22V of the first container section 20V to be locked to the outer edge of the second container section 30V.

[0048] [Third embodiment] A knee bolster 10W of a third embodiment is shown in Figures 10 to 12. As shown in Figure 10, the knee bolster 10W of this embodiment includes a front wall 25 and a rear wall 26 that are elongated and generally rectangular and sandwich a rigid polyurethane foam 40W in a first direction A1, and a pair of connecting walls 27 that connect both longitudinal ends of the front wall 25 and the rear wall 26. The pair of connecting walls 27 are formed into plate shapes that are curved away from each other.

[0049] In addition, a surrounding wall 28 protruding toward the front wall 25 is provided on the rear wall 26. The surrounding wall 28 protrudes to a midpoint between the rear wall 26 and the front wall 25 in the first direction A1, and has an open end in a direction intersecting the first direction A1 where the pair of connecting walls 27 are not disposed, thereby housing the rigid polyurethane foam 40W in a state surrounded from three sides.

[0050] A cantilever-shaped retaining piece 29 is provided at the center of the front wall 25 in the longitudinal direction, and its tip is curved toward the rear wall 26. This retaining piece 29 prevents the rigid polyurethane foam 40W from coming off the surrounding wall 28 in the lateral direction.

[0051] As shown in Fig. 11, the energy absorbing rib 12W includes a plurality of first ribs 13A1 and a plurality of second ribs 13B1 that are inclined at an angle of 45 degrees with respect to both the vertical and horizontal directions of the rear wall 26 and are perpendicular to each other, and a third rib 16 that intersects with the intersection of the first and second ribs 13A1 and 13B1 and extends in both the vertical and horizontal directions of the rear wall 26. In detail, the plurality of first and second ribs 13A1 and 13B1 form square cells 14W, and the length of the diagonal of the cells 14W is slightly smaller than the length in the short direction (i.e., the horizontal direction) of the rear wall 26. For example, two cells 14W are arranged in the vertical direction of the rear wall 26, and each cell 14W is adjacent to another cell at one vertex. The plurality of third ribs 16 extend in the diagonal direction, intersecting three of the vertices of each cell 14W. The shape of energy absorbing rib 12W is symmetrical with respect to the longitudinal centerline of rear wall 26. Other than as described above, the configuration of knee bolster 10W of this embodiment is the same as that of knee bolster 10 of the first embodiment.

[0052] The configuration of this embodiment also provides the same effects as those of the first embodiment. In addition, in the knee bolster 10W of this embodiment, when the rigid polyurethane foam 40W is compressed, the pair of connecting walls 27 elastically deform, and the front wall 25 moves closer to the rear wall 26, and the front wall 25 abuts against the tip of the surrounding wall 28, completing the compression collapse of the rigid polyurethane foam 40W.

[0053] In this embodiment, the front wall 25 and the tip of the surrounding wall 28 correspond to a "stopper portion" in the claims.

[0054] [Other embodiments] (1) In the above embodiment, the squares 14 of the energy absorbing rib 12 were configured so that their diagonals were arranged parallel to the longitudinal and lateral directions of the bottom wall 31 of the second container section 30. However, as in the knee bolster 10X shown in FIG. 13, the vertical and horizontal sides of the squares 14X may be arranged parallel to the vertical and horizontal sides of the bottom walls 21X, 31X of the first container section 20X and the second container section 30X.

[0055] (2) In the first embodiment described above, the entire rigid polyurethane foam 40 was contained in the container 11, but it is also possible to simply provide a plate member between the rigid polyurethane foam and the energy absorbing rib to prevent the energy absorbing rib from digging into the rigid polyurethane foam, or to impregnate the rigid polyurethane foam on the energy absorbing rib side with non-foamed urethane or the like for reinforcing purposes.

[0056] (3) In the above first embodiment, the progression of compression failure stops when the side wall 32 of the second container section 30 abuts against the bottom wall 21 of the first container section 20 before the entire rigid polyurethane foam 40 is completely compressed and destroyed. However, the compression failure may continue until the rigid polyurethane foam 40 is completely compressed and destroyed.

[0057] (4) In the second embodiment described above, the first and second container sections 20V, 30V are formed with a plurality of protruding cylindrical stopper portions 24A, 24B, and when the rigid polyurethane foam 40V is compressed to failure, the tips of the stopper portions 24A, 24B come into contact with each other, thereby completing the compression failure of the rigid polyurethane foam 40V. However, as in the knee bolster 10Y shown in FIG. 14, a locking claw 24T having a right-angled triangular cross section protrudes outward along the tip edge of the stopper portion 24A1 of the first container section 20Y, while an engagement hole 24K is formed in the circumferential direction near the tip of the stopper portion 24B1 of the second container section 30Y, and when the rigid polyurethane foam 40Y is compressed to failure, the locking claw 24T engages with the engagement hole 24K, thereby completing the compression failure of the rigid polyurethane foam 40Y.

[0058] (5) In the first embodiment, the second container section 30 and the energy absorbing rib 12 are integrally formed, but they may be separate bodies.

[0059] (6) In the above embodiment, the energy absorbing ribs 12, 12V, 12W are lattice-shaped, but they may have any structure that protrudes in the first direction A1 and buckles when pressed in the first direction A1. For example, the ribs may have a cross-shaped cross section, a cylindrical shape, an elliptical cylindrical shape, a square cylindrical shape, or a honeycomb shape.

[0060] (7) In the above embodiment, the rigid polyurethane foams 40, 40V, 40W are arranged on the front side and the energy absorbing ribs 12, 12V, 12W are arranged on the rear side in the first direction A1. However, the arrangement may be reversed.

[0061] In addition, although this specification and drawings disclose specific examples of the technology included in the scope of the claims, the technology described in the claims is not limited to these specific examples, but includes various modifications and variations of the specific examples, as well as parts of the specific examples taken alone. [Explanation of symbols]

[0062] 10,10V,10W,10X Knee Bolster 11,11V,11W container 12,12V,12W Energy absorbing ribs 14,14W,14X square 20, 20V, 20X First container division 21, 21V Bottom wall (rib support wall) 26 Lower wall (rib support wall) 22,22V side wall 30,30V,30X 2nd container division 31 Bottom Wall 32 Side wall 34 Reinforcing rib 40,40V,40W Hard polyurethane foam

Claims

1. A knee bolster that supports the knees of an occupant during a vehicle collision, A first member that is compressed and destroyed by a pressing force from the knee and a second member that buckles are arranged in a first direction in which the pressing force is received, A knee bolster, wherein the second member has a greater strength than the first member.

2. The first member is disposed between a pair of opposing members, 2. The knee bolster according to claim 1, wherein one of said pair of opposing members is said second member.

3. the first member is a rigid polyurethane foam; The knee bolster of claim 1 or 2, wherein the second member includes an energy absorbing rib.

4. a pair of container sections formed by dividing a container that accommodates the first member in the first direction, the container sections engaging with each other so as to restrict movement in a direction intersecting the first direction, and the fitting between the container sections deepening as the first member is compressed and destroyed; 4. The knee bolster according to claim 1, wherein the second member is disposed on at least one of the pair of container sections.

5. 5. The knee bolster according to claim 4, wherein said pair of container sections form a container structure having opposing sides open to each other.

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