JP5494450B2 - Vehicle knee bolster - Google Patents

Description

  The present invention relates to a vehicle knee bolster that restrains an occupant's knee when a vehicle collides.

  In the knee bolster for automobiles shown in Patent Document 1 below, a hard urethane pad (energy absorbing member) supported by an instrument panel reinforcement via a metal bracket is disposed to face an occupant's knee. The This hard urethane pad absorbs the impact energy of the knee by being crushed by a load from the knee of the occupant at the time of a car collision.

JP 2003-31429 A

  However, the rigid urethane pad has a restriction on the length of foaming due to production technology, and is easy to break when crushed (easy to break against a compressive load), so it cannot be formed so long. Therefore, the length of the metal bracket (fixed portion) to which the hard urethane pad is fixed cannot be set short, and there is room for improvement in terms of mass reduction. In addition, since the hard urethane pad is easily cracked with respect to the compressive load as described above, the variation of the load-displacement characteristic may be very large.

  The present invention has been made in consideration of the above facts, and an object of the present invention is to obtain a vehicle knee bolster that can stabilize the load-displacement characteristics of the energy absorbing member and reduce the mass.

  In order to solve the above-described problem, the vehicle knee bolster according to the invention described in claim 1 is disposed in front of a knee portion of an occupant seated on a vehicle seat and is provided on a rigid member on the vehicle body side. An energy absorbing member having a front end fixed to a fixed portion is provided, and the energy absorbing member includes a dilatant portion made of a material having a dilatant characteristic, and a support portion that is formed of a resin material and supports the dilatant portion. It is characterized by.

  In the vehicle knee bolster according to the first aspect, the energy absorbing member is disposed in front of the knee portion of the occupant seated on the vehicle seat. This energy absorbing member has a front end side fixed to a fixing portion provided on a rigid member (instrument reinforcement, etc.) on the vehicle body side, and has a dilatant portion made of a material having dilatant characteristics. Since the dilatant portion is supported by the resin support portion, the shape of the soft dilatant portion can be maintained normally. On the other hand, at the time of a vehicle collision or the like, an impact is applied to the energy absorbing member from the knee portion of the occupant who intends to move inertially toward the front side of the vehicle. As a result, the dilatant portion is instantly cured to restrain the occupant's knee, and the impact energy of the knee is absorbed to protect the knee.

  Moreover, the energy absorbing member including the resin support portion can be prevented from cracking by instantly curing the dilatant portion. Thereby, a load-displacement characteristic can be stabilized. Furthermore, since the dilatant portion has a high degree of freedom in shape and is difficult to break, it is possible to achieve both lengthening and weight reduction. Thereby, since the length dimension of an energy absorption member can be lengthened and the structure of the fixing | fixed part in a vehicle body side rigid member can be simplified, the mass of an apparatus can be reduced. That is, for example, when the metal bracket attached to the main body portion (pipe material or the like) of the instrument panel reinforcement is used as the fixed portion, the length of the metal bracket can be set short. Further, for example, a metal bracket can be omitted by setting a part of the main body of the instrument panel reinforcement as a fixed part and fixing the energy absorbing member directly to the fixed part. This makes it possible to reduce the mass of the device.

  A vehicle knee bolster according to a second aspect of the present invention is the vehicle knee bolster according to the first aspect, wherein the support portion is a case formed in a hollow shape, and the dilatant portion is a portion of the case. It is characterized by being disposed inside.

  In the vehicle knee bolster according to claim 2, since the soft dilatant portion is normally disposed in the resin case formed in a hollow shape, the shape of the dilatant portion can be satisfactorily maintained. .

  A vehicle knee bolster according to a third aspect of the present invention is the vehicle knee bolster according to the second aspect, wherein the case and the dilatant portion are formed in a bottomed cylindrical shape having an opening on the fixed portion side. It is characterized by that.

  In the vehicle knee bolster described in claim 3, since both the case and the dilatant portion are formed in a bottomed cylindrical shape, the energy absorbing member can be easily formed by integral molding or the like. In addition, since the dilatant portion has a bottomed cylindrical shape, the amount of the material having the dilatant characteristic can be reduced, so that the cost and the weight can be reduced.

  As described above, in the vehicle knee bolster according to the present invention, the load-displacement characteristic of the energy absorbing member can be stabilized and the mass can be reduced.

1 is a perspective view showing a configuration of a vehicle knee bolster according to a first embodiment of the present invention. It is a disassembled perspective view which shows the partial structure of the vehicle knee bolster which concerns on 1st Embodiment of this invention. It is an expanded sectional view which shows the cut surface along the 3-3 line of FIG. It is sectional drawing which shows the cut surface along line 4-4 in FIG. It is a perspective view which shows the modification of the energy absorption member which is a structural member of the knee bolster for vehicles which concerns on 1st Embodiment of this invention. It is sectional drawing corresponding to FIG. 3 which shows the energy absorption member which is a structural member of the knee bolster for vehicles which concerns on 2nd Embodiment of this invention. It is a front view of the energy absorption member which is a structural member of the vehicle knee bolster which concerns on 3rd Embodiment of this invention. It is a perspective view which shows the partial structure of the knee bolster for vehicles which concerns on 4th Embodiment of this invention.

<First Embodiment>
Hereinafter, with reference to FIGS. 1-5, the vehicle knee bolster 10 which concerns on 1st Embodiment of this invention is demonstrated. In each figure, the arrow FR indicates the vehicle front direction, the arrow UP indicates the vehicle upward direction, the arrow LH indicates the vehicle left direction, and the arrow RH indicates the vehicle right direction.

  The vehicle knee bolster 10 according to the first embodiment is a device (lower limb restraint device) for restraining both knees of an occupant seated in a driver seat (seat) of a right-hand drive vehicle, which is shown in FIG. As shown, the instrument panel reinforcement 12 and a pair of left and right energy absorbing members 14 are included. The instrument panel reinforcement 12 is disposed inside an instrument panel (not shown) provided at the front of the vehicle interior, and extends in the vehicle width direction to connect the left and right vehicle body panels (in FIG. 1). Only a part of the instrument panel reinforcement 12 is shown).

  The main body 18 of the instrument panel reinforcement 12 is formed of a long metal pipe material. The main body 18 has a thick portion on the driver's seat side that requires strength and a thin portion on the passenger seat side that does not require much strength. A metal column support portion 20 (column bracket) for attaching a steering column is attached to a portion of the main body portion 18 on the driver's seat side. A pair of left and right metal brackets 22 that are fixing portions for fixing the energy absorbing member are disposed on both the left and right sides of the column support portion 20.

  These metal brackets 22 are formed in an open cross-sectional shape (cross-sectional U-shape) by bending a metal plate, and as shown in FIG. 2, an upper wall 22A, a lower wall 22B, and a vertical wall 22C. It has. However, these metal brackets 22 are formed symmetrically and both open to the column support portion 20 side. These metal brackets 22 are formed so that the size in the vertical direction becomes smaller toward the front end side, and the front end portion is welded to the main body portion 18 of the instrument panel reinforcement 12.

  An upper fastening piece 22D extends upward from the rear end of the upper wall 22A of the metal bracket 22, and lower fastening from the rear end of the lower wall 22B of the metal bracket 22 downward. The piece 22E is extended. The energy absorbing member 14 is fastened and fixed to the upper fastening piece 22D and the lower fastening piece 22E.

  As shown in FIGS. 2 to 4, the energy absorbing member 14 includes a case 15. The case 15 is formed of a resin material into a thin bottomed cylindrical shape, and is disposed with the opening 15A facing the metal bracket 22 and the bottom wall 15B facing an instrument panel (not shown). Yes. The case 15 has an elliptical cross-sectional shape as viewed from the metal bracket 22 side, and has a tapered shape (substantially truncated cone) that reduces the peripheral length of the peripheral wall 15C toward the bottom wall 15B side (rear end side). Formed). Moreover, this case 15 is arrange | positioned in the state in which the long diameter of an elliptical cross section follows a vehicle up-down direction.

  An upper fastening portion 15D extends upward from the upper end portion of the opening edge portion of the case 15, and the lower fastening portion 15E extends downward from the lower end portion of the opening edge portion of the case 15. Has been extended. A circular through hole 24 is formed in the upper fastening portion 15D. The bolt 28 inserted into the circular through hole 24 is screwed into the screw hole 32 formed in the upper fastening piece 22D of the metal bracket 22, whereby the upper fastening portion 15D is fastened and fixed to the upper fastening piece 22D. ing. Similarly, a circular through hole 26 is formed in the lower fastening portion 15E. The bolt 30 inserted through the circular through hole 26 is screwed into a screw hole 34 formed in the lower fastening piece 22E of the metal bracket 22, so that the lower fastening portion 15E is engaged with the lower fastening piece 22E. Fastened and fixed. Thereby, the case 15 is fixed to the metal bracket 22.

A dilatant portion 16 that constitutes the energy absorbing member 14 together with the case 15 is disposed inside the case 15. The dilatant portion 16 is made of a material having a dilatant characteristic, for example, “d3o ^™ ” manufactured by d3o ^™ lab of England, and is integrally formed with the case 15 in this embodiment. This “d3o ^™ ” is a material that is flexible when no impact is applied or when the impact is weak, but is instantly cured when a strong impact is applied, and exhibits excellent energy absorption performance.

  The dilatant portion 16 is formed in a bottomed cylindrical shape having an opening on the metal bracket 22 side, and the opening 16 </ b> A is disposed in a state of facing the metal bracket 22. The dilatant portion 16 has an elliptical cross-sectional shape as viewed from the metal bracket 22 side, the bottom wall 16B is in close contact with the surface of the bottom wall 15B of the case 15 on the metal bracket 22 side, and the peripheral wall 16C is The case 15 is in close contact with the inner peripheral surface of the peripheral wall 15C. In FIG. 2, illustration of the bottom wall 16B and the peripheral wall 16C is omitted for convenience of explanation.

  In the vehicle knee bolster 10 configured as described above, when the occupant P is seated in the driver's seat of the vehicle, the left energy absorbing member 14 is positioned in front of the left knee portion P1 of the occupant P as shown in FIG. The right energy absorbing member 14 is arranged in front of the right knee portion P1 of the occupant P.

  Next, the operation and effect of the first embodiment will be described.

  In the vehicle knee bolster 10 configured as described above, since the dilatant portion 16 constituting the energy absorbing member 14 is disposed in the resin case 15, the shape of the dilatant portion 16 can be normally held by the case 15. it can. On the other hand, at the time of a vehicle collision or the like, an occupant's knee P1 that is about to move inertially forward with respect to the vehicle body collides with the energy absorbing member 14 via instrument panel reinforcement. As a result, the dilatant portion 16 is instantly cured and restrains the knee portion P1 of the occupant P, and absorbs the impact energy of the knee portion P1 to protect the knee portion P1.

  Moreover, the energy absorbing member 14 including the resin case 15 can be prevented from cracking by instantly curing the dilatant portion 16. Thereby, a load-displacement characteristic can be stabilized. Furthermore, since the energy absorbing member 14 can be prevented from cracking as described above, the length L (see FIG. 3) of the energy absorbing member 14 can be set long (the length dimension L is not limited). . Thereby, since the length dimension of metal bracket 22 can be shortened significantly, the mass of an apparatus can be reduced.

  Further, in the present embodiment, since the dilatant portion 16 that is normally soft is disposed in the resin case 15 formed in a bottomed cylindrical shape (hollow shape), the shape of the dilatant portion 16 is well maintained. can do.

  Moreover, in this embodiment, since both the case 15 and the dilatant part 16 are formed in bottomed cylindrical shape, the energy absorption member 14 can be easily shape | molded by integral molding. Further, since the dilatant portion 16 is formed in a bottomed cylindrical shape, it is possible to reduce the cost and weight of the device while ensuring good knee restraint performance.

  That is, when the knee part P1 of the occupant P collides with the energy absorbing member 14, an impact is applied to the bottom wall 16B of the dilatant part 16, whereby the molecules of the material of the dilatant part 16 are instantaneously bonded to each other. The entire wall 16B and the peripheral wall 16C are instantly cured. Thus, since the bottom wall 16B functions like a sensor for curing the dilatant portion 16, the dilatant portion 16 can be cured quickly and satisfactorily. In addition, a load can be generated satisfactorily by the peripheral wall portion 16C having an elliptical cross section. Thereby, favorable knee restraint performance is securable. Furthermore, since the dilatant part 16 is hollow, the usage-amount of the material which has a dilatant characteristic can be reduced. Thereby, cost reduction and weight reduction of an apparatus can be achieved.

  Furthermore, the energy absorbing member 14 according to the present embodiment is fixed to the metal bracket 22 in a state where the major axis of the elliptical cross section is along the vehicle vertical direction. That is, since the vertical dimension of the energy absorbing member 14 is set to be large, the energy absorbing member 14 can be satisfactorily opposed to the knee regardless of variations in the arrangement height of the knee due to the physique difference of the occupant. it can. Moreover, since it can avoid that the energy absorption member 14 interferes with a steering column etc., it is suitable also when ensuring the arrangement space of the energy absorption member 14. FIG.

  Further, in the present embodiment, by changing the length dimension, the cross-sectional shape, the thickness, etc. of the energy absorbing member 14, the magnitude of the load generated when the energy absorbing member 14 is crushed or the energy absorbing member 14 is crushed. The stroke can be freely adjusted, and there is an advantage that the degree of freedom in design is high.

  In the first embodiment, the energy absorbing member 14 (the case 15 and the dilatant portion 16) is configured to have an elliptical cross section. However, the invention according to claims 1 to 3 is not limited thereto, The cross-sectional shape of the energy absorbing member 14 can be changed as appropriate. For example, as in the modification shown in FIG. 5, the energy absorbing member 14 may be formed in a substantially rectangular cross section. Although not shown, the energy absorbing member 14 may be formed in a circular cross section.

  Next, another embodiment of the present invention will be described. In addition, about the structure and effect | action similar to the said 1st Embodiment, the same code | symbol as the said 1st Embodiment is provided, and the description is abbreviate | omitted.

<Second Embodiment>
FIG. 6 shows a cross-sectional view of an energy absorbing member 40 which is a constituent member of a vehicle knee bolster according to the second embodiment of the present invention. The energy absorbing member 40 has basically the same configuration as the energy absorbing member 14 according to the first embodiment. However, in the energy absorbing member 40, the dilatant portion 15 is thinner than the first embodiment. Is formed. Further, the peripheral wall 15C of the case 15 is provided with a step portion 42 at an axially intermediate portion, and the peripheral wall 16C of the dilatant portion 16 is formed with a step portion 44 at a portion corresponding to the step portion 42 of the case 15. ing. Other component configurations are basically the same as those of the first embodiment.

  In this embodiment, when the knee portion P1 of the occupant P collides with the energy absorbing member 40 via the instrument panel, the case 15 and the dilatant portion 16 are buckled at the step portions 42 and 44. During the buckling, the dilatant portion 16 exhibits excellent energy absorption performance, and thus the knee portion P1 can be well protected. The step portions 42 and 44 may be omitted, and a weak portion (such as a thin portion) may be provided in the middle portion in the axial direction of the dilatant portion 16.

<Third Embodiment>
FIG. 7 shows a front view of an energy absorbing member 50 which is a constituent member of a vehicle knee bolster according to the third embodiment of the present invention. The energy absorbing member 50 has basically the same configuration as the energy absorbing member 14 according to the first embodiment. However, in the energy absorbing member 50, the upper fastening portion 15D of the case 15 protrudes toward one side in the minor axis direction of the elliptical cross section, and the lower fastening portion 15E faces the other side in the minor axis direction of the elliptical cross section. Protruding. Thus, by arrange | positioning upper side fastening part 15D and lower side fastening part 15E, the dimension of the energy absorption member 50 along the major axis direction of an elliptical cross section can be set small. Therefore, the molding die of the energy absorbing member 50 can be made small and low cost. In this case, it is necessary to change the arrangement of the upper fastening piece 22D and the lower fastening piece 22E of the metal bracket 22 in accordance with the arrangement of the upper fastening part 15D and the lower fastening part 15E.
<Fourth Embodiment>
FIG. 8 is a perspective view showing a partial configuration of a vehicle knee bolster according to the fourth embodiment of the present invention. Although this embodiment has basically the same configuration as the first embodiment, the metal bracket 22 according to the first embodiment is omitted in this embodiment. In this embodiment, the configuration of the energy absorbing member 60 is different from that of the energy absorbing member 14 according to the first embodiment.

  The case 15 of the energy absorbing member 60 is formed in a tapered shape (substantially frustoconical shape) in which the circumferential length of the peripheral wall 15C increases toward the bottom wall 15B side (rear end side). In addition, although illustration is abbreviate | omitted, the dilatant part 16 is also formed in the taper shape which the surrounding length of 16 C of surrounding walls expands as it goes to the bottom wall 16B side.

  The front end portion of the energy absorbing member 60 is in contact with a fixing portion 62 provided on the main body portion 18 of the instrument panel reinforcement 12. The upper fastening portion 15D of the case 15 is curved so as to be in close contact with the upper surface of the main body portion 18, and the screw 28 penetrating the upper fastening portion 15D is screwed into a screw hole (not shown) formed in the upper portion of the fixing portion 62. Match. Accordingly, the upper fastening portion 15D is fastened and fixed to the fixing portion 62 (a part of the main body portion 18). The lower fastening portion 15E is curved so as to be in close contact with the lower surface of the fixing portion 62, and the screw 30 penetrating the lower fastening portion 15E is inserted into a screw hole (not shown) formed in the lower portion of the fixing portion 62. It is screwed. Accordingly, the lower fastening portion 15E is fastened and fixed to the fixing portion 62 (a part of the main body portion 18).

  As described above, in this embodiment, a part of the main body portion 18 of the instrument panel reinforcement 12 is the fixing portion 62 for fixing the energy absorbing member, and the main body portion 18 directly receives the reaction force of the energy absorbing member 60. It has become. Thereby, since the metal brackets 22 can be omitted, the mass of the apparatus can be greatly reduced.

  In each of the above embodiments, the case 15 (support portion) and the dilatant portion 16 are formed in a bottomed cylindrical shape. However, the invention according to claim 1 and claim 2 is not limited thereto, and the case and The shape of the dilatant portion can be changed as appropriate. For example, the case may be configured in a box shape, or the dilatant portion may be formed in a honeycomb shape or a lattice shape and fitted in the case.

  In each of the above embodiments, the case 15 and the dilatant portion 16 are integrally formed. However, the invention according to claims 1 to 3 is not limited thereto, and the case and the method for forming the dilatant portion are appropriately changed. can do. For example, the case and the dilatant part may be formed separately, and the dilatant part may be bonded to the case.

  Further, in each of the above embodiments, the dilatant portion 16 is supported by the case 15 as the support portion. However, the invention according to claim 1 is not limited to this, and the dilatant portion is not prepared for the support portion in normal times. Any shape can be used as long as it is supported so as not to be deformed, and the shape can be changed as appropriate. For example, the support portion may be embedded in the dilatant portion.

  In addition, the present invention can be implemented with various modifications without departing from the scope of the invention. Further, it goes without saying that the scope of rights of the present invention is not limited to the above embodiments.

DESCRIPTION OF SYMBOLS 10 Knee bolster for vehicles 12 Instrument panel reinforcement 14 Energy absorption member 15 Case (support part)
16 Dilatant part 22 Metal bracket (fixed part)
40 energy absorbing member 50 energy absorbing member 60 energy absorbing member 62 fixing portion

Claims (3)

An energy absorbing member that is disposed in front of a knee portion of an occupant seated on a vehicle seat and has a front end fixed to a fixing portion provided in a rigid member on a vehicle body side;
The energy absorbing member is
A dilatant portion made of a material having a dilatant characteristic;
A support portion formed of a resin material and supporting the dilatant portion;
A vehicle knee bolster characterized by comprising:   The vehicle knee bolster according to claim 1, wherein the support portion is a case formed in a hollow shape, and the dilatant portion is disposed inside the case.   3. The vehicle knee bolster according to claim 2, wherein the case and the dilatant portion are formed in a bottomed cylindrical shape having an opening on the fixed portion side. 4.

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