JP5291432B2 - Knee bracket and car occupant knee protection method - Google Patents

Description

  The present invention relates to a knee bracket (an automobile occupant's knee support, a knee protection member, a knee panel support bracket, etc.) and an automobile occupant's knee protection method, which are made of a hollow aluminum alloy and have excellent energy absorption performance. .

  2. Description of the Related Art Conventionally, a vehicle body such as an automobile has been provided with a knee bracket called a knee protector or a knee bolster that protects an occupant's knee (also referred to as a leg) in a vehicle collision. For this knee bracket, an aluminum alloy extruded hollow member is often used as a material from the viewpoint of weight reduction and energy absorption performance.

  For the purpose of protecting the occupant's knees, the knee bracket is disposed between the occupant and the vehicle body in the front-rear direction of the vehicle body in front of the front seat. The end portion on the rear side of the vehicle body is fixed to a knee panel (pressure receiving plate, receiving plate, etc.) facing the occupant's knee, while the end portion on the front side of the vehicle body is fixed to the vehicle body. The fixing to the vehicle body is usually performed by being joined to an instrument panel reinforcing member provided in front of the vehicle interior for supporting the steering column. The instrument panel reinforcement is a long tubular member extending in the vehicle body width direction, and is also called an instrument panel reinforcement, a steering support beam, a steering humber beam, or a cross car beam.

  The knee bracket has a cross-section that extends in the longitudinal direction of the vehicle body in order to secure the amount of collision energy absorbed by the plastic body in the longitudinal direction of the occupant's knees and the continuous plastic deformation in the longitudinal direction of the vehicle body. The shape (partition) must have a certain length (stroke). If this stroke is short, the absorption of collision energy cannot be absorbed, the load on the knee increases, and the knee of the occupant cannot be protected.

  Accordingly, the knee bracket (partition wall) is required to have a small initial load for starting the plastic deformation so as not to damage the occupant's knee. In addition, during the plastic deformation in the range of the stroke, local deformation or the like does not occur, and bending or breakage does not occur, and the plastic deformation can be continuously performed to keep a certain amount of collision energy absorption. Required. In other words, the knee bracket is required to have a crushing characteristic that ensures both the amount of energy absorption necessary for the passenger's knee collision and the injury damage to the passenger's knee.

  On the other hand, various types of cross-sectional shapes (overall cross-sectional shapes extending in the longitudinal direction of the vehicle body) for exhibiting excellent crushing characteristics have been proposed for knee brackets made of extruded aluminum alloy hollow members. For example, Patent Document 1 has a fixed-length partition wall integrally formed in a horizontal pantograph shape (diamond shape) so as to sequentially plastically deform from the knee panel mounting side to the vehicle body front side. .

  Further, in Patent Documents 2 and 3, the knee bracket is disposed in front of the knee so as to face diagonally upward from below to the position of the occupant's knee, and is a long frame (face plate) that curves upward. ) And plate-like ribs connecting them, a plurality of truss-shaped or square-shaped partition walls are formed. And like the said patent document 1, a partition is plastically deformed sequentially from the attachment side of a knee panel to the vehicle body front. As described above, the partition walls such as these are usually integrally formed of an aluminum alloy extruded hollow member, as described above, for the purpose of weight reduction and its complicated cross-sectional structure.

  However, in the partition wall integrally formed from these conventional aluminum alloy extruded hollow members, the length of the partition wall that can exhibit the required performance as an occupant protection member is limited. On the other hand, there has also been proposed an aluminum alloy knee bracket that can freely adjust the length of the partition wall according to the car body, and can secure and freely adjust the amount of collision energy absorption. For example, in Patent Documents 4 and 5, etc., a plurality of aluminum alloy hollow shapes having a diamond-shaped cross section are connected to each other in the cross-sectional direction to form an energy absorption portion, and the partition wall length can be adjusted. Knee brackets that have been secured in quantity have been proposed.

US Pat. No. 3,931,988 JP-A-5-238338 JP 2003-127814 A Japanese Patent Laid-Open No. 2005-53437 Japanese Patent Laid-Open No. 2005-53438

  These proposed knee brackets made of a hollow aluminum alloy material, if the overall shape in the longitudinal direction of the vehicle body between the occupant and the vehicle body is generally linear, including linear and arc shapes, etc. Predetermined crushing load characteristics can be obtained, and excellent energy absorption performance is easily exhibited.

  However, depending on the positional relationship with the dash box provided in the front of the passenger compartment and the shape of the knee panel facing the occupant's knee, if the knee bracket is straight, other vehicle bodies such as the dash box Interference with parts can occur.

  In order to prevent such interference, it is necessary to bend and deform the knee bracket relatively largely so as to bypass the interference part instead of being linear. That is, it is necessary to bend the knee bracket into a V-shape or a U-shape at a location where the knee brackets interfere with each other at a degree of bending that can prevent interference with other vehicle body parts such as a dash box disposed on the vehicle body.

  However, when the knee bracket is bent relatively large as described above, there is a problem that it is difficult to obtain a predetermined crushing load characteristic in the knee bracket made of the aluminum alloy hollow shape member. This is because, in the case of a vehicle collision, when the pushing force (crushing load) of the knee of the occupant is applied in the longitudinal direction of the vehicle body of the knee bracket via the knee panel, the crushing direction at the bent portion is different (shifts greatly). It depends.

  Normally, the knee bracket is generally linear in the longitudinal direction of the vehicle body (including some overall curved shape), and is disposed substantially linearly in the longitudinal direction of the vehicle body. Therefore, the direction of the pushing force (crushing load) of the occupant's knee, that is, the assumed loading direction of the pushing force of the occupant's knee and the crushing direction of the knee bracket are not significantly different, such as coming on the same line. It is easy to obtain a predetermined crushing load characteristic.

  However, if the knee bracket is bent relatively large in order to prevent the interference, a large shift occurs between the pushing force direction and the crushing direction. Local deformation and unstable deformation are likely to occur. When this local deformation occurs in the middle of plastic deformation of the knee bracket (partition wall), as described above, bending and breakage are likely to occur, and the plastic deformation is continuously performed to keep a certain amount of collision energy absorption. It becomes difficult. In other words, the crushing characteristic that achieves both the load that does not damage the knee bracket, which is required for the knee bracket, and the necessary amount of energy absorption when the passenger collides with the knee is achieved. become unable.

  And this tendency is because the extension direction of the knee panel (pressure receiving plate) that receives the pushing force of the occupant's knee is inclined from the direction perpendicular to the pushing force direction of the occupant's knee. This is also promoted when the direction of the load is different from the direction of the pushing force. That is, even in such a case, the knee bracket made of the aluminum alloy hollow profile is likely to be unstablely deformed, and the predetermined crushing load characteristic cannot be obtained.

  Therefore, an object of the present invention is to provide a case where there is a large deviation between the direction of the pushing force of the occupant's knee and the direction of crushing, such as bending the knee bracket relatively large, or the direction of the load acting at the time of collision is The present invention is intended to provide an aluminum alloy knee bracket and a method for protecting a knee of an automobile occupant that can exhibit the above-mentioned crushing characteristics required for a knee bracket even when the direction of the pushing force is different from that of the vehicle.

In order to achieve this object, the gist of the knee bracket of the present invention is disposed in front of the front seat in the automobile cabin and has the following requirements a to f .
a. The knee bracket is made of a single aluminum alloy extruded hollow member, and is arranged such that the extrusion direction of the extruded member is the vehicle body width direction.
b. This single aluminum alloy extruded hollow member is composed of at least a pair of face plates and a plurality of plate-like ribs connecting the face plates.
c. The ends of the pair of face plates on the rear side of the vehicle body are fixed to a knee panel facing the occupant's knees as load points, while the ends of the pair of face plates on the vehicle body front side are fixed to the vehicle body. It is a supporting point.
d. Each of the face plates has a V-shaped or U-shaped cross-sectional shape that is bent downward.
e. Of the face plates, the lower face plate is thinner than the upper face plate.
f. When the occupant's knee collides with the knee panel, the knee bracket is deformed downward by the configuration of d and e.

  Here, in the present invention, it is assumed that the knee bracket is a virtual connection line connecting the bending points in the V-shaped or U-shaped cross-sectional shape of the face plate, and the knee of the occupant to the knee panel at the time of a vehicle body collision. It is preferable that they are arranged in the longitudinal direction of the vehicle body so as to be perpendicular to the direction of the pushing force. It is preferably used when the extending direction of the pressure receiving portion of the knee panel is inclined from a direction perpendicular to the assumed pushing force direction of the occupant's knee. Further, it is preferable that the knee bracket has a bending degree in a longitudinal direction of the vehicle body that can prevent interference with a dash box disposed on the vehicle body.

  Furthermore, the gist of the vehicle occupant knee protection method of the present invention is a method of protecting the vehicle occupant's knee using the knee bracket of any of these gist, and the occupant's knee collides with the pressure receiving portion of the knee panel. In this case, the knee bracket is deformed downward to alleviate the impact of the passenger's knee collision.

  In the present invention, the knee bracket is made of a single aluminum alloy extruded hollow shape, and the requirements a to c described above are substantially the same as those of the conventional knee bracket made of a single aluminum alloy extruded hollow shape. is there.

  However, the present invention is based on the premise that the knee brackets (face plates) each have a V-shaped or U-shaped cross-sectional shape that is bent downward (in the longitudinal direction of the vehicle body) as in the requirement d. To do. In addition, as in the requirement e, the thickness of the lower face plate of the face plates is smaller than the thickness of the upper face plate. Thus, as in the gist of the vehicle occupant knee protection method of the present invention, when the occupant's knee collides with the pressure-receiving portion of the knee panel, the knee bracket is deformed downward so that the occupant's knee Reduce the impact of collision.

  In other words, according to the present invention, a V-shaped or U-shaped cross-sectional shape of the knee bracket itself extending in the longitudinal direction of the vehicle body between the load point and the support point of the knee bracket is a so-called bending structure. It is deformed downward to mitigate the impact of the passenger's knee collision. The effect of the present invention is that the knee bracket of the present invention has the above-mentioned V-shaped or U-shaped cross-sectional shape in order to prevent interference with a vehicle body member such as a dash box, and greatly increases in the vehicle longitudinal direction. Most exhibited when bent (curved). However, since the knee bracket bent as in the present invention has a large difference between the pushing force direction and the crushing direction, when a pushing force (crushing load) due to a knee collision of the occupant is applied, a predetermined amount is applied. Crushing load characteristics cannot be obtained, and inevitably local deformation or unstable deformation easily occurs in the knee bracket.

  On the other hand, in the present invention, when an occupant's knee collides with the pressure receiving portion (load point) of the knee panel, the knee bracket itself has a V-shaped or U-shaped cross-sectional shape extending in the longitudinal direction of the vehicle body, As a so-called bending structure, the knee structure is deformed downward to prevent local deformation or unstable deformation of the knee bracket. As a result, predetermined crushing load characteristics can be obtained, and the impact of the passenger's knee collision can be greatly reduced. In the present invention, when the pushing force due to the knee collision of the occupant is applied, the downward bending deformation is positively generated in the cross-sectional portion extending in the longitudinal direction of the vehicle body between the load point and the support point of the knee bracket. To achieve this effect.

  Therefore, according to the present invention, the thickness of the lower face plate is larger than the thickness of the upper face plate, as in the requirement e, so that the bending deformation of the knee bracket becomes dominant. Also make it thinner. As a result, when both the upper and lower face plates have the same thickness or the upper face plate is thicker, when the pushing force due to the knee collision of the occupant is loaded, the knee bracket Bending deformation becomes dominant.

  Further, according to the present invention, in addition to these structural features, the imaginary connecting line is used as a method of arranging or attaching the knee bracket so that bending deformation in the bent structure is dominant. It is preferable that the vehicle is disposed in the longitudinal direction of the vehicle body so as to be perpendicular to the direction of the assumed pushing force of the occupant's knee to the knee panel during the collision. The virtual connecting line referred to here is a bending point (inflection point or bending portion vertex) in the V-shaped or U-shaped cross-sectional shape of the face plate, and connects the bending points of the upper and lower face plates. It is a virtual connection line. By doing in this way, the deformation | transformation by the pushing force by the said passenger's knee collision concentrates on each bending point thru | or the said virtual connection line of the said faceplate. As a result, even if the knee bracket is bent relatively large in the longitudinal direction of the vehicle body in order to prevent interference with the vehicle body member, even if there is a large deviation between the pushing force direction and the crushing direction, On the other hand, local deformation and unstable deformation at sites other than the respective bending points are less likely to occur.

  As described above, according to the present invention, even if the knee bracket is bent relatively large in the longitudinal direction of the vehicle body in order to prevent interference with the vehicle body member, the amount of energy absorption required when the passenger collides with the knee is reduced. It is possible to ensure both securing and not damaging the occupant's knees. According to the present invention, even if the knee bracket is not relatively bent in the longitudinal direction of the vehicle body in order to prevent interference with the vehicle body member, there is a large deviation between the pushing force direction and the collapse direction of the knee bracket. This is effective in some cases or when the direction of the load acting at the time of collision is different from the direction of the pushing force of the occupant's knee.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, FIGS. 1 and 2 show a basic configuration and operational effects (mechanism) of the knee bracket of the present invention. 1 and 2 are cross-sectional views of the knee bracket in the longitudinal direction of the vehicle body (also a side view), and FIG. 2 shows a state in which the knee bracket of FIG. 1 is deformed by the pushing force of the occupant's knee at the time of the vehicle body collision. Show. 1 and 2 are arranged in the vehicle interior so that the section of the knee bracket extends in the front-rear direction of the vehicle body (the left direction in FIG. 1 is the front side), which is the left-right direction in FIGS. Is done.

(Basic structure)
In FIG. 1, a knee bracket 1 is made of a single aluminum alloy extruded hollow member, and a plurality of (four) reinforcing plate-like ribs 4 connecting the pair of face plates 2 and 3 and the face plates. 5, 6, 7. In the cross section of the knee bracket 1 extending in the longitudinal direction of the vehicle body, the pair of face plates 2 and 3 are arranged such that the upper face plate 2 and the lower face plate 3 Extend substantially parallel to each other in the longitudinal direction of the vehicle body.

  The pair of face plates 2 and 3 are bent in the longitudinal direction of the vehicle body and bent or curved into a V shape or a U shape. This is to prevent interference with other vehicle body parts and members such as a dash box provided in the front of the vehicle interior by the V-shape or U-shape, which is the bent portion, as will be described later.

  The extruded cross-sectional shape of these aluminum alloy extruded hollow members in FIG. 1 is a basic cross-sectional configuration extending in the longitudinal direction of the vehicle body of the knee bracket 1. In addition, the extrusion direction of the extruded hollow shape member in FIG. 1 is a direction perpendicular to the longitudinal direction of the vehicle body in FIG. 1 (left-right direction in FIG. 1) and from the front of FIG.

  The pair of face plates 2 and 3 and the plate-like ribs 4, 5, 6 and 7 in the single aluminum alloy extruded hollow member constituting the knee bracket 1 have a vehicle body width as shown in FIG. The plate has a predetermined uniform plate width in the direction, and this plate width defines the width of the knee bracket 1 in the vehicle body width direction.

  Here, the meaning of “at least” used for the configuration of the knee bracket 1 is for joining to other vehicle body members such as the flanges 9 and 9 and the end plate 8 shown in FIG. 1 in addition to these face plates and plate-like ribs. It means that it may have necessary parts and parts such as. In FIG. 1, the necessary portions and parts other than the face plate and the plate-like rib, such as the flanges 9 and 9 and the end plate 8, are also made of a single aluminum alloy extruded hollow shape, and are previously combined with the face plate and the plate-like rib. It is hot extruded as a unit. However, depending on how to attach to other vehicle body members, necessary parts and parts for joining to these other vehicle body members are separately prepared as necessary, and the knee bracket 1 (aluminum alloy extruded hollow member) ) May be joined later.

  The flanges 9, 9 are flanges for joining to the instrument panel reinforcement member 20, which is a vehicle body, projecting forward from the respective end portions 2 b, 3 b on the vehicle body front side of the face plates 2, 3 (to the left side in FIG. 1). . The flanges 9 and 9 are selectively provided in the knee bracket 1 including the shape and structure thereof according to the selection and design of the shape and position of the vehicle body member or the vehicle body member that fixes the knee bracket 1 or the joining means. It is done.

(Support point and load point of knee bracket)
In the embodiment of FIG. 1, the knee bracket 1 is fixed to the vehicle body so that the outer peripheral portion of the instrument panel reinforcing member 20 is sandwiched between the flanges 9 and 9, and the end portions on the vehicle body front side of the pair of face plates 2 and 3 are fixed. It is a supporting point. The joining itself is joined by mechanical joining means such as bolts and rivets.

  Further, the end plate 8 is an end plate (with a flange projecting in the vertical direction of the vehicle body) provided at each of the end portions 2c, 3c on the vehicle body rear side of the face plates 2, 3 for joining to a knee panel (not shown). The end plate 8 is fixed to the knee panel 30 facing the occupant's knee, and is used as a load point at the end of the pair of face plates 2 and 3 on the vehicle body rear side.

  The end plate 8 is selectively provided on the knee bracket 1 including its shape and structure according to the position and shape of the knee panel to be fixed, which will be described later, or the selection and design of the joining means. The knee panel is usually made of resin, and no special consideration is required for joining with the aluminum alloy knee bracket 1. In this regard, when the knee bracket 1 is bonded to a steel member with a different material, it is necessary to interpose an insulating film or coating film for preventing electrolytic corrosion. Further, in the case of joining different materials to such steel members, joining by welding alone is not preferable in terms of joining strength, and it is preferable to use only mechanical joining or mechanical joining in combination. On the other hand, when the knee bracket 1 is joined to the same aluminum alloy member, no special consideration is required.

(Thickness of face plate)
Here, as shown in FIG. 1, the thickness of the lower face plate 3 among the face plates 2 and 3 is thinner than the thickness of the upper face plate 2. As a result, the strength and rigidity of the bending point 12 in the central portion 3a of the face plate 3 are reduced, and the bending deformation of the bending structure is more likely to occur. Therefore, the effect that the deformation due to the pushing force concentrates on the bending points 11 and 12 or the virtual connecting line 13 between the face plates 2 and 3 and the effect that the bending deformation becomes dominant are easily exhibited.

  However, the difference thickness effect in which the thickness of the lower face plate 3 is smaller than the thickness of the upper face plate 2 is based on the assumption that the knee bracket itself is bent. If the cross-sectional shape of the knee bracket in the longitudinal direction of the vehicle body is linear, the difference in thickness effect that the thickness of the lower face plate 3 is thinner than the thickness of the upper face plate 2 simply weakens the strength of the face plate 3 and the knee bracket itself. And it has the opposite effect.

  Here, in order to obtain the differential thickness effect in which the thickness of the lower face plate 3 is smaller than the thickness of the upper face plate 2, the thickness of the lower face plate 3 may be the entire region extending in the longitudinal direction of the vehicle body. As shown in FIG. 1, only the central portion of the lower face plate 3 may be used. That is, FIG. 1 shows such a case, in which only the central region sandwiching the bending point 12 in the central portion 3a of the lower face plate 3 is partially thinned, and both end portions near the support point and load point of the knee bracket. Is the same as the thickness of the upper face plate 2. However, the thickness of the entire face plate 3 and the thickness of the face plate 3 in the periphery of the face plate 3 may be partially made thinner than the thickness of the upper face plate 2 within a range that does not adversely affect the strength.

(Extension direction and pressure direction of pressure receiving surface)
In the embodiment of FIG. 1, the end plate 8 extending in the vertical direction of the vehicle body, together with the end portions 2c and 3c on the vehicle body rear side of the face plates 2 and 3, is assumed to be the pushing force of the occupant's knee (hereinafter, assumed) The pressure receiving surface for the occupant's knee pushing force or pushing force) is simply omitted. In the case of FIG. 1, the pushing force direction indicated by the arrow and the dotted line 14 (occupant's knee locus) in FIG. 1 is the lateral direction of FIG. However, the angle and direction of the pushing force direction are different depending on the mounting position of the knee bracket 1 because the mounting position itself of the knee bracket 1 is not limited to the horizontal direction but is inclined at an angle.

  The extension direction (vertical direction of the vehicle body) of the pressure receiving surface constituted by the end portions 2c and 3c on the vehicle body rear side of the end plate 8 and the face plates 2 and 3 on the vehicle body rear side of the knee bracket 1 is shown in FIG. It is preferably substantially perpendicular to the assumed pushing force direction indicated by the arrow and dotted line 14 (occupant's knee trajectory). If the extending direction of the pressure receiving surface and the direction of the pushing force are substantially perpendicular, the effect of the deformation caused by the pushing force is concentrated on the bending points 11 and 12 or the virtual connecting line 13 between the face plates 2 and 3; The effect that the bending deformation in the bending structure becomes dominant is exhibited to the maximum.

  However, FIG. 1 shows a case where the extending direction of the pressure receiving surface with respect to the direction of the pushing force cannot be substantially perpendicular to the direction of the pushing force in the vehicle body design. In the vehicle body design, when the extension direction of the pressure-receiving surface is greatly inclined from the right angle with respect to the expected occupant's knee pushing force direction, the occupant's knee pushing force direction is substantially lateral in the figure, As shown in FIG. 1, the extending direction of the pressure-receiving surface is greatly deviated from the vertical (vertical) direction in the figure and is greatly inclined toward the rear side of the vehicle body (to the right side in the figure).

  In such a case, according to the configuration of the present invention, the effect of the deformation due to the pushing force concentrating on the bending points 11 and 12 or the virtual connecting line 13 between the face plates 2 and 3 is hardly exhibited. That is, when the pushing force of the passenger's knee is applied, the pressure receiving surface is deformed so as to rotate counterclockwise. As a result, according to the configuration of the present invention, the deformation due to the pushing force is not concentrated on the bending points 11 and 12 or the virtual connecting line 13 between the face plates 2 and 3, and the bending deformation may not be dominant. . For this reason, local deformation | transformation and unstable deformation | transformation of a knee bracket cannot be prevented and the possibility that the said stable crushing load characteristic will become difficult to obtain arises.

  However, also in this respect, it is effective that the thickness of the lower face plate 3 is smaller than the thickness of the upper face plate 2. That is, when the thickness of the lower face plate 3 is thinner than the thickness of the upper face plate 2, the strength and rigidity of the bending point 12 in the central portion 3a of the face plate 3 are reduced, and the bending deformation is more likely to occur. Therefore, as shown in FIG. 1, even when the extending direction of the pressure receiving surface with respect to the direction of the pushing force cannot be perpendicular, the deformation due to the pushing force causes the bending points 11, 12 of the face plates 2, 3 or the virtual connection. The effect of concentrating on the line 13 and the effect of dominant bending deformation are easily exhibited.

(Bent structure)
In the embodiment of FIG. 1, in order to make the bending deformation more dominant, preferably, in addition to the differential thickness effect in which the thickness of the lower face plate 3 is smaller than the thickness of the upper face plate 2, A bent structure is formed between the load point (end plate 8) and the support point (flange 9, 9). This bent structure has a cross-sectional shape similar to a shape such as “arrow blade”, and can be said to be a V-shaped or U-shaped cross-sectional shape. Then, when the occupant's knee collides with the pressure receiving portion (load point: end plate 8) of the knee bracket 1 through the knee panel, the bending structure is deformed downward to cause local deformation of the knee bracket 1 or Unstable deformation is prevented. As a result, predetermined crushing load characteristics can be obtained, and the impact of the passenger's knee collision can be greatly reduced.

  In this way, the deformation of the knee bracket 1 in the longitudinal direction of the vehicle body in the longitudinal direction of the vehicle body due to the pushing force is more dominant in the downward deformation of the bending structure than the other cross-sectional portions. . As a result, the knee bracket is required even when there is a large difference between the direction of the pushing force of the occupant's knee and the direction of crushing, or when the direction of the load applied during a collision is different from the direction of the pushing force of the occupant's knee. It is possible to achieve the desired crushing properties.

  In the embodiment of FIG. 1, the face plates 2 and 3 are bent into a V shape or a U shape for the purpose of preventing interference with other body parts and members such as a dash box. The bending structure provided for the purpose of providing a portion that is easily bent positively in the knee bracket also has a V-shaped or U-shaped cross-sectional shape. Therefore, by combining these, the entire knee bracket 1 also has a shape that is bent or curved into a V shape or a U shape in the vehicle longitudinal direction.

  The configuration of the bent structure in FIG. 1 will be specifically described below. In the knee bracket 1, the pair of face plates 2 and 3 are bent downward at the center portions 2a and 3a. That is, the upper face plate 2 has a bending point (lowermost point) 11, and the face plate 3 has a bending point (lowermost point) 12. The plate-like ribs 5 and 6 in which the bent portions (or the bent portions 2a and 3a in the center portion) of the center portions 2a and 3a of the face plates 2 and 3 are adjacent to each other in parallel in the vehicle longitudinal direction with respect to a virtual connecting line 13 described later. In addition, a bent structure is formed. That is, the bent points 11 and 12 are apexes at the center of the vehicle body in the longitudinal direction of the knee bracket 1 by the bent portions 2a and 3a at the center of the face plates 2 and 3 and the plate-like ribs 5 and 6 adjacent in parallel. A bent structure having a V-shaped or U-shaped cross-sectional shape is formed.

  In order for the bending deformation in the bending structure to be dominant, the bending structure is provided with a portion that is most likely to be crushed and has a small load and is weak so that the bending deformation is positively generated. In this bent structure, the most easily crushable portions where the load is small and weak are the bending points 11 and 12 of the bending at the central portions 2a and 3a of the face plates 2 and 3, respectively. It is the presence of a portion along the virtual connecting line 13 to be connected.

  However, this bending structure is not simply weakened. Local deformation, cracking, or unstable deformation of this bending structure occurs due to the urging force applied to the occupant's knee during a vehicle collision. In order to prevent the occurrence of the bending and positively generate the downward bending deformation, a certain strength and rigidity as a structure is required.

  For this purpose, among the plate-like ribs, the plate-like ribs 5 and 6 that are adjacent to each other with the virtual connection line 13 in between are provided in parallel to the virtual connection line 13. Accordingly, in FIG. 1, the plate-like ribs 5 and 6 are provided so that their directions are substantially vertical (in the vertical direction of the vehicle body). The plate-shaped ribs 5 and 6 and the bent portions 2a and 3a in the center portion of the face plate are V-shaped between the load point (end plate 8) and the support points (flanges 9 and 9) of the knee bracket 1. It is formed as a structure having a cross-sectional shape similar to the “arrow blade” having a shape or a U-shaped cross-sectional shape.

  The plate-like ribs 5 and 6 that are adjacent to the virtual connecting line 13 in the longitudinal direction of the vehicle body are vertically parallel to each other as long as they are parallel to the virtual connecting line 13. The direction of the direction does not necessarily have to be vertical as shown in FIG. That is, the plate-like ribs 5 and 6 may be provided in parallel with each other and inclined in the vertical direction of the vehicle body.

  On the other hand, when the plate-like ribs 5 and 6 are not parallel to the virtual connection line 13 but are provided with a relatively large inclination in the vertical direction of the vehicle body so as to approach or separate from each other. The deformation due to the pressing force does not concentrate on the bending points 11 and 12 or the virtual connecting line 13 of the bending at the central portions 2a and 3a of the face plates 2 and 3.

(How to install the knee bracket)
Further, in the present invention, in addition to the above-described configuration, the virtual connection line is connected to the knee panel at the time of a vehicle body collision in addition to the above-described configuration, as a method of mounting or mounting the knee bracket. It is arranged in the longitudinal direction of the vehicle body so as to be perpendicular to the assumed pushing force direction of the occupant's knee.

  That is, in FIG. 1, the imaginary connecting line 13 of the knee bracket 1 is perpendicular to the assumed pushing force direction of the occupant's knee at the time of the vehicle collision shown by the arrow and the dotted line 14 in FIG. It should be arranged in the front-rear direction. In FIG. 1, since the pushing force direction is substantially horizontal, the virtual connecting line 13 is also substantially perpendicular to the direction perpendicular thereto. Even when the pushing force direction is inclined from the horizontal, the direction of the virtual connecting line 13 is substantially perpendicular to the pushing force direction.

  With this configuration, the weakest part of the knee bracket 1 can be actively bent and deformed. In other words, with respect to the deformation of the cross-sectional portion of the knee bracket 1 extending in the longitudinal direction of the vehicle body due to the pushing force, the bending points 11 and 12 of the bending at the central portions 2a and 3a of the face plates 2 and 3 and the virtual connection line The bending deformation at the site along 13 can be dominant.

  In the case of FIG. 1, the pushing force direction indicated by the arrow and the dotted line 14 is substantially horizontal. If the pressure receiving surface of the knee panel passenger (not shown) and the end plate 8 are parallel to the direction of the pushing force, The extending direction is almost a right angle (vertical). Here, the pushing force direction is not limited to the case of being substantially horizontal in terms of vehicle body design, but may naturally be inclined from the horizontal direction. However, regardless of the direction of the pushing force, when the extending direction of the pressure receiving surface is substantially perpendicular to the direction of the pushing force, the deformation due to the pushing force is caused by the configuration of the present invention. The effect of concentrating on the bending points 11 and 12 or the virtual connecting line 13 between the face plates 2 and 3, in other words, the effect of causing the bending structure to be bent downward is exerted to the maximum.

(Knee bracket deformation mechanism)
FIG. 2 shows a state in which the knee bracket 1 of FIG. 1 is deformed by the pushing force of the occupant's knee at the time of the vehicle body collision. The dotted line indicates the initial shape of the knee bracket 1 of FIG. Each bracket 1 is shown. FIG. 2 is also a summary of the deformation analysis results of the knee bracket 1 shown in FIGS.

  As can be seen from FIG. 2, according to the above-described configuration of the present invention, the deformation due to the pushing force is concentrated on the bending points 11 and 12 or the virtual connecting line 13 at the central portions 2a and 3a of the face plates 2 and 3. I understand that And, the structure portion of the “arrow blade” shape constituted by the plate-like ribs 5 and 6 and the bent portions 2a and 3a at the center portion of the face plate does not cause local deformation or cracking, or unstable deformation, It can be seen that the shape of the entire structure is bent and deformed downward.

  For this reason, even if the knee bracket 1 is bent relatively large in the longitudinal direction of the vehicle body to prevent interference with the vehicle body member, and the large displacement occurs between the pushing force direction and the crushing direction, the face plate In regions other than the bending points 11 and 12 or the virtual connecting line 13 (the bending structure) in the central portions 2a and 3a, local deformation and unstable deformation are unlikely to occur. As a result, in order to prevent the knee bracket 1 from interfering with the vehicle body parts and members, even if the knee bracket 1 is bent relatively large in the longitudinal direction of the vehicle body, a necessary energy absorption amount at the time of a passenger's knee collision is ensured. And that only a load that does not cause damage is applied to the occupant's knees.

(Overall shape of knee bracket)
In the case of FIG. 1, as described above, the knee bracket 1 has a shape bent or curved into a V shape or a U shape as an overall shape in the longitudinal direction of the vehicle body. As described above, this is because the V-shaped or U-shaped cross-sectional shape of the bent structure and the entire V-shaped or U-shaped faceplate 2 including the peripheral portion of the bent structure in the longitudinal direction of the vehicle body. This is because the shapes (angle, size, etc.) of the cross-sectional shapes of these are the same.

  However, these shapes do not necessarily coincide with each other as shown in FIG. 1, and the V-shaped or U-shaped cross-sectional shape of the entire face plates 2 and 3 and the V-shaped or U-shaped bent structure are formed. Of course, the angle and size of the cross-sectional shape may be changed. For example, the bent portion is only the central bent structure, and the face plates 2 and 3 in the front and rear direction of the bent structure are not bent at the same angle as the bent structure, for example, a flat shape (FIG. 1). The peripheral face plates 2 and 3 may extend in the horizontal or horizontal direction. In this case, the knee bracket 1 as a whole (as a cross-sectional shape extending in the longitudinal direction of the vehicle body) is linear without being bent except for the central bent structure. The meaning of the V-shape or U-shape described above includes not only the shape of a V-shape or U-shape in a strict sense but also a shape that approximates a V-shape or U-shape and can be said to be a V-shape or U-shape. It can be.

  If the entire shape of the knee bracket 1 is simply linear or slightly curved as in the conventional case, the arrangement angle of the knee bracket 1 in the longitudinal direction of the vehicle body is changed so that the vehicle body is not horizontal. Even if it is inclined at an angle in the vertical direction, it is difficult to prevent interference with other body parts and members such as a dash box. On the other hand, in the present invention, since the bent portion is provided in the central portion of the knee bracket 1, even if the entire shape of the knee bracket is linear, except for the bent portion of the central portion, It is easy to avoid interference with other body parts and members at the bent portion. However, the bending degree of the bent portion or the entire knee bracket 1 can be bent relatively large as in the embodiment of FIG. 1 so that it can be bypassed by preventing interference with other body parts and members. preferable.

  More specifically, the bent portions 2a and 3a at the center of the face plate 2 and 3 preferably have a downward bending degree that can prevent interference with a dash box or the like disposed on the vehicle body. Of course, this degree of bending must ensure downward bending deformation of the bent structure formed by the plate-like ribs 5 and 6 and the bent portions 2a and 3a at the center of the face plate. However, although it depends on the vehicle body design (the shape and size of the dash box, etc.) for each passenger car model, the bending degree that can prevent interference is quantified while ensuring the downward bending deformation of the bending structure. As for the degree of bending, when the length L of the cross section of the knee bracket 1 in the longitudinal direction of the vehicle body is about 120 to 200 mm, the bending angle with respect to the straight line is about 80 to 120 degrees.

(Aspect of plate-like rib)
In FIG. 1, in addition to the plate-like ribs 5 and 6 constituting the bent structure, the plate-like ribs 4 and 7 are provided on the front and rear sides of the vehicle body with the virtual connecting line 13 interposed therebetween. That is, in FIG. 1, two plate-like ribs 4 and 5 are provided on the vehicle body front side and two plate-like ribs 6 and 7 are provided on the vehicle body rear side across the virtual connecting line 13.

  The plate-like ribs 4 and 7 are also reinforcing ribs for improving the deformation strength of the face plates 2 and 3, similarly to the plate-like ribs 5 and 6 constituting the bent structure. However, since the plate-like ribs other than the plate-like ribs 5 and 6 such as the plate-like ribs 4 and 7 do not constitute the bent structure, the position, direction, number, and the like of the plate-like ribs 5 and 6 6 can be provided more freely. In other words, the plate-like ribs that do not constitute the bent structure are disposed between the face plates 2 and 3, and both end portions thereof are joined to the face plates 2 and 3, respectively, and generally extend in the vertical direction of the vehicle body. As long as it is sufficient, the position, orientation, number, etc., can be freely selected according to the required reinforcement. By the way, the number of plate-like ribs that do not constitute the bent structure is a plurality of ribs that can improve the deformation strength, and 1 to 3 on each side of the vehicle front direction or the rear direction, 2 to 6 in total. It is preferable to provide a plurality of books.

  It is not always necessary to provide the same number of plate-like ribs on the front and rear sides of the vehicle body. However, if the same number is not used, the bending deformation at the bending points 11 and 12 of the central portions 2a and 3a of the face plates 2 and 3 and the portions along the virtual connecting line 13 is more surely dominant. In addition, the design conditions for this may be difficult. For this reason, also in FIG. 1, two plate-like ribs 4 and 5 are provided on the front side of the vehicle body, and two plate-like ribs 6 and 7 are provided on the rear side of the vehicle body.

  Furthermore, the distance between the plate-shaped ribs on the front and rear sides of the vehicle body, the installation angle, the arrangement of the face plates 2 and 3 and the like are arranged symmetrically in the vehicle front-rear direction with the virtual connection line 13 as the center. Is preferred. Also in FIG. 1, the plate-like ribs 4 and 5 on the front side of the vehicle body and the two plate-like ribs 6 and 7 on the rear side of the vehicle body are provided symmetrically in the longitudinal direction of the vehicle body with the virtual connection line 13 as the center. It has been. By these, the effect of improving the deformation strength of the face plates 2 and 3 by the plate-like ribs is further increased, and at the portions along the bending points 11 and 12 and the virtual connecting lines 13 at the central portions 2a and 3a of the face plates 2 and 3. The bending deformation of the can be controlled more reliably.

  It should be noted that the manner of providing the plate-like ribs on the front and rear sides of the vehicle body may be changed on the front and rear sides of the vehicle body without necessarily making the plane symmetrical in the vehicle body front and rear direction. For example, the plate-like ribs 5 and 6 adjacent to the virtual connecting line 13 in the vehicle longitudinal direction are parallel to each other, and the plate-like ribs 4 on the vehicle body front side and the plate-like ribs 6 and 7 on the vehicle body front-rear side are positioned. While the same, the plate-like rib 5 on the front side of the vehicle body may be brought closer to the virtual connecting line 13. Further, the distance between the plate-like ribs on the front and rear sides of the vehicle body can be basically freely designed from the viewpoint of reinforcing the face plate as long as the function of the bent structure is not impaired.

  In this respect, in FIGS. 1 and 2, from the viewpoint of reinforcing the face plate, distances d (intervals) between the provided ribs and the upper face plate 2 are the distances between the intersections with the lower face plate 3. Shorter than the distance d. On the front side of the vehicle body, the distance d1 (interval) between the intersections of the plate ribs 4 and 5 with the upper face plate 2 is shorter than the distance d2 between the intersections with the lower face plate 3. On the rear side of the vehicle body, the distance d3 (interval) between the intersections of the plate ribs 6 and 7 with the upper face plate 2 is shorter than the distance d4 between the intersections with the lower face plate 3. Incidentally, in FIGS. 1 and 2, the intersection of the plate ribs 4 and 5 with the upper face plate 2 and the intersection of the plate ribs 6 and 7 with the upper face plate 2 are adjacent, and d1 and d3 are almost zero. Yes, the plate-like ribs 4 and 5 and the plate-like ribs 6 and 7 form an inverted V-shape (cross-sectional shape).

  As described above, the bending structure is such that the distance (interval) between each plate-like rib and the upper face plate 2 is shorter than the distance d between each cross-point with the lower face plate 3. There is also an advantage that body deformation can be controlled more reliably. As an example of such a configuration, in the case of FIGS. 1 and 2, each intersection of the plate-like ribs 4 and 5 on the front side of the vehicle body and the plate-like ribs 6 and 7 on the rear side of the vehicle body with the upper face plate 2 is located at the same position. As described above, the distance between the intersections is eliminated, and the distance between the intersections with the lower face plate 3 is made shorter. Therefore, in the case of FIGS. 1 and 2, the plate-like ribs 4 and 5 on the front side of the vehicle body and the plate-like ribs 6 and 7 on the rear side of the vehicle body are adjacent to the virtual connecting line 13 in the longitudinal direction of the vehicle body. The plate-like ribs 5 and 6 are formed in an inverted V shape by being parallel to the virtual connecting line 13.

(Knee bracket mounting mode)
Next, the aspect of the present invention in which the knee bracket is attached to the interior of the automobile will be described. FIG. 3 is a perspective view showing this aspect. 4 is a cross-sectional view of the existing portion of the knee bracket of FIG. 3 (the knee bracket on the left side of FIG. 3) in the vehicle longitudinal direction. In FIG. 3, the knee bracket 1 is disposed in front of a driver's seat (right side in the passenger compartment), which is a front seat in an automobile interior, or in front of a leg portion 51 of an occupant 50 sitting in the driver's seat. An embodiment is shown. The aspect of the knee bracket 1 is basically the same on the passenger seat side (the left side in the passenger compartment) on the opposite side of the vehicle body width direction.

  Here, in the knee bracket 1 of FIGS. 3 and 4, the thickness of the lower face plate 3 among the face plates 2 and 3 is thinner than the thickness of the upper face plate 2, as in FIG. 1. As a result, the strength and rigidity of the bending point 12 in the central portion 3a of the face plate 3 are reduced, and the bending deformation of the bending structure is more likely to occur. Therefore, as described above, the effect of concentrating the deformation due to the pushing force at the bending points 11 and 12 or the virtual connecting line 13 between the face plates 2 and 3 and the effect of dominant bending deformation are easily exhibited. ing.

  Two knee brackets 1 are provided spaced apart from each other in the vehicle body width direction indicated by an arrow, and are disposed in front of the front seat in the above-described automobile cabin and extending in the vehicle body front-rear direction. The number of knee brackets 1 is usually two as shown in FIG. 3, but the number itself is not particularly limited as long as it is a necessary number. As described above, the knee bracket 1 has a longitudinal direction so that the extrusion direction indicated by the arrow of the single aluminum alloy extruded hollow shape material is the vehicle body width direction or parallel to the vehicle body width direction. These are arranged in the vehicle interior so as to be in a direction perpendicular to this.

  The end portions 2c and 3c on the vehicle body rear side of the pair of face plates 2 and 3 are connected to the knee panel 30 facing the occupant's knee via the end plate 8 by mechanical joining means 66 such as bolts and rivets. Fixed. 3 and 4 are the same as those shown in FIGS. 1 and 2 in that the end plate 8 for joining to the knee panel is provided at the end portions 2c and 3c on the vehicle body rear side of the pair of face plates 2 and 3, respectively. However, the flange protruding in the vertical direction of the vehicle body, such as the end plate 8 in FIGS. The shapes of the end plate 8 and the flange thereof are appropriately selected including the shape and structure according to the position and shape of the knee panel to be fixed or the selection and design of the joining means.

  On the other hand, the end portions 2b, 3b on the vehicle body front side of the pair of face plates 2, 3 are connected to mechanical joining means 61, 62, 63 (such as bolts and rivets) via joining flanges 9, 9. It is not shown and is fixed to the instrument panel reinforcement member 20 which is a vehicle body by 64 (lower side of 61) and 64 (lower side of 62).

  Here, 9, 9 is spaced from the end portions 2b, 3b on the front side of the vehicle body of the face plates 2, 3 forward (to the left side in FIG. 1) in the vertical direction of the vehicle body, as in FIGS. And a flange for joining to the instrument panel reinforcement member 20 which is a vehicle body, which extends in parallel. The shapes of the flanges 9 and 9 are appropriately selected including the shape and structure according to the selection and design of the shape and position of the vehicle body member or the vehicle body member that fixes the knee bracket 1 or the joining means. 3 and 4, as in FIGS. 1 and 2, the knee bracket 1 is fixed to the vehicle body with the flanges 9 and 9 sandwiching the outer peripheral portion of the instrument panel reinforcement member 20, and bolts, rivets, etc. It joins by the mechanical joining means 61-64.

  3 and 4, the knee bracket 1 has a pair of face plates 2 and 3 that are bent downward at the center portions 2a and 3a thereof, as in FIGS. That is, the upper face plate 2 has a bending point (lowest point) 11, the face plate 3 has a bending point (lowest point) 12, and the overall shape of the cross section of the knee bracket 1 in the vehicle longitudinal direction is the bending point 11. , 12 as a vertex, and a V-shape or U-shape. This V-shaped or U-shaped bend has a size (flexibility) sufficient to prevent interference with other body parts and members such as the dash box 40 provided in the front of the vehicle interior.

  On the other hand, when the knee bracket 1 is linear or slightly curved, the arrangement angle of the knee bracket 1 in the longitudinal direction of the vehicle body is changed so that the angle is not in the horizontal direction but in the vertical direction of the vehicle body. Even if it is tilted, it cannot prevent interference with other body parts and members such as a dash box. In other words, the knee bracket 1 is not linear but needs to be bent and deformed relatively large so as to bypass a portion that interferes with other body parts and members. That is, it is necessary to bend the knee bracket into a V-shape or a U-shape at a location where the knee brackets interfere with each other at a degree of bending that can prevent interference with other vehicle body parts such as a dash box disposed on the vehicle body.

  Assuming that the knee bracket 1 is bent in this manner, the knee bracket 1 is configured so that the virtual connecting line 13 is connected to the knee panel 30 at the time of a vehicle collision by the occupant 50's knee indicated by an arrow as in FIGS. It is arrange | positioned in the vehicle body front-back direction so that it may become a right angle with respect to 51 assumed pushing force directions.

(Hollow profile design)
The design of the cross section of the knee bracket 1 in the longitudinal direction of the vehicle body (extrusion cross section of the aluminum alloy hollow extruded member) as shown in FIG. 1 is the design condition of the vehicle body and the effect of the present invention (when the pushing force is applied) , Central portions 2a and 3a of the face plates 2 and 3: determined by design conditions for the portion along the imaginary connecting line 13 to be most easily crushed and to bend and deform. The design of the cross section of the knee bracket 1 in the longitudinal direction of the vehicle body (extrusion cross section of the aluminum alloy hollow extrusion) is the length of the knee bracket 1 (cross section) extending in the longitudinal direction of the vehicle body, ), The width of the knee bracket 1 extending in the vehicle body width direction, the plate thickness and length of the face plate and the plate-like rib, the arrangement position, and the like.

  Here, each ratio of the length L of the optimum or practical knee bracket 1 (cross section), the height H of the knee bracket 1 (cross section), and the width W of the knee bracket 1 in the vehicle body width direction is L Is about 100 to 200 mm, L / H is about 1.8 to 3.5, and L / W is about 60 to 80. If the ratio of L or L becomes too large beyond these lower limits, the stroke of the knee bracket 1 becomes too long, and the crushing strength of the cross section extending in the longitudinal direction (vehicle body longitudinal direction), which is the energy absorbing portion, decreases. With respect to the pushing force (collision energy), the plastic deformation cannot be performed, and bending or breakage easily occurs in the longitudinal direction. For this reason, plastic deformation cannot be performed with a small collision load with the knee (the pushing force), and there is a possibility that the amount of collision energy (the pushing force) absorbed cannot be ensured between the strokes.

  The wall thickness (wall thickness or plate thickness) of the face plate, plate-like rib, end plate, and joining flange of the knee bracket 1 is 5 mm or less in order to take advantage of the use of aluminum alloy for weight reduction. Is preferably thin. In the present invention, even if the thickness is 5 mm or less, it is possible to enhance the impact absorption effect when the occupant collides with the knee, and the thickness exceeds 5 mm from the viewpoint of minimizing the weight increase of the vehicle body. There is no need. In accordance with the thickness of the upper face plate determined by this, the thickness of the lower face plate is made thin and designed together with the area to be thinned. Moreover, it is not necessary to make the thickness (wall thickness) of the face plate, the plate-like rib, the end plate, the flange for joining, etc. all the same, and may be appropriately changed from the viewpoint of achieving the effect of the present invention and reducing the weight.

  In order to reduce the thickness and weight of the knee bracket 1 as described above, the higher the strength of the aluminum alloy used, the better. However, in the present invention, local deformation and unstable deformation are unlikely to occur, and in order to ensure the bending deformation of the bent structure at the center portion of the face plate, the medium strength of 0.2% proof stress is in the range of 150 to 220 MPa. Thus, it is preferable that the material has a high elongation. If the degree of work hardening (n value) is small, the applied load (strain) tends to concentrate on one point, and local deformation (including cracks and breaks) or unstable deformation tends to occur. On the other hand, when the degree of work hardening (n value) is large, the plastic regions of the bent portions 2a and 3a that are bent and deformed of the bent structure easily spread, the applied load is dispersed, and the local deformation Or unstable deformation is less likely to occur.

  As an aluminum alloy material satisfying these required characteristics, general-purpose (standard) aluminum alloys such as 5000 series, 6000 series, and 7000 series defined in AA to JIS standards are generally used for this kind of structural member application. An extruded hollow member produced by hot extrusion is suitably and selectively used after tempering or heat treatment corresponding to the required performance. However, among these tempered materials of aluminum alloy, an overaged material such as T7 of 6000 series aluminum alloy such as 6063 is particularly preferable as the material having the medium strength and high elongation.

  The results of analyzing the deformation caused by the pushing force with respect to the shapes of the various knee brackets described above are shown below as examples.

  5 and 6 show analysis results of the invention example knee bracket of the differential thickness face plate in which the thickness of the lower face plate 3 in FIG. 1 is smaller than the thickness of the upper face plate 2. FIG. 5 is a cross-sectional view (side view) in the longitudinal direction of the vehicle body showing the change with time of the deformation of the knee bracket, and FIG. 6 is an explanatory diagram showing load displacement curves of the respective analysis results of FIG.

  On the other hand, FIGS. 7 and 8 show analysis results of the comparative example knee bracket in the case where the upper and lower face plates 2 and 3 have the same thickness. FIG. 7 is a cross-sectional view (side view) in the longitudinal direction of the vehicle body showing the change over time of the deformation of the knee bracket, and FIG. 8 is an explanatory view showing a load displacement curve of each analysis result of FIG.

  Each of FIGS. 5 and 7 shows a change over time in the load deformation state for each displacement (amount) in the load displacement curve of each of FIGS. 5 and 7 in order from the left side of each figure in FIG. 5 and FIG. 7 before the push (push amount 0 mm), push (amount) = displacement (amount) 10 mm, push (amount) 20 mm, and push (amount) 30 mm over time. Showing change.

  The analysis is based on a static crush analysis of the deformation over time and the load-displacement relationship when assuming the load load of the pushing force due to the knee collision from the rear side of the vehicle body (occupant side: right side of the figure) to the knee bracket. Asked. As the analysis software, a general-purpose finite element solver ABAQUS was used. The material hollow extruded shape was commonly used as a T7 tempered material of 6000 series 6063 aluminum alloy extruded hollow shape, and the 0.2% proof stress was 170 MPa.

  The thickness of the upper face plate 2 among the face plates 2 and 3 of the invention example knee bracket of FIG. 5 is 4.8 mm, and the thickness of the lower face plate 3 is 3.6 mm, which is thinner than the thickness of the upper face plate 2. The thickness of the plate-like ribs was commonly set to 4.0 mm. On the other hand, the thicknesses of the face plates 2 and 3 and the plate-like ribs of the comparative example knee bracket of FIG. The outer dimensions of the knee bracket are commonly the length L: 120 mm, the height H: 60 mm, the width W is 30 mm, L / H is 2.0, and L / W is about 40. The bending angle with respect to the straight line was 120 degrees.

  The distances d1 and d3 between the intersection points of the four plate-like ribs 4, 5 and 6 and 7 with the face plates 2 and 3 are set to 0 mm, and d2 and d4 are set to 20 mm in both the invention example of FIGS. . Among these plate-like ribs, the plate-like ribs 5 and 6 adjacent to the virtual connecting line 13 in the longitudinal direction of the vehicle body are parallel to the virtual connecting line 13 and the direction thereof is substantially vertical (the vehicle body (In the vertical direction). Further, the intervals between the plate-like ribs on the front and rear sides of the vehicle body, the installation angle, the arrangement of the face plates 2 and 3 and the like are arranged symmetrically in the vehicle front-rear direction with the virtual connection line 13 as the center.

  5 and 7, as described above, the extending direction of the pressure-receiving surface is not greatly perpendicular to the assumed direction of the occupant's knee pushing force, but greatly deviates from the right-angle direction, and the rear side of the vehicle body It is greatly inclined (to the right side of the figure).

  As can be seen from FIG. 6, the knee bracket of the invention example of FIG. 5 can reduce the maximum load in load displacement, and has a small collision load commensurate with the occupant's knee collision, and the cross-sectional direction (width direction) necessary for energy absorption Can cause plastic deformation. In addition, even if displacement due to plastic deformation progresses, local deformation or partial breakage does not occur, the amount of load decrease is extremely small, energy is continuously absorbed over the stroke of the knee bracket, and the occupant's It can be seen that the amount of energy absorption necessary for the knee collision can be secured.

  On the other hand, in the comparative example knee bracket of FIG. 8, when the occupant's knee pushing force is applied, the pressure-receiving surface is counterclockwise as shown by the solid line after the deformation from the original shape indicated by the thin solid line. It will be deformed to rotate. As a result, the deformation due to the pushing force does not concentrate on the bending points 11 and 12 or the virtual connecting line 13 between the face plates 2 and 3, the bending deformation does not occur, the amount of load decrease is large, and the stable crushing load described above. It is difficult to obtain characteristics.

  These results support the significance of each requirement of the knee bracket of the present invention, particularly the effect of providing the bent structure.

  ADVANTAGE OF THE INVENTION According to this invention, even when a knee bracket is bent comparatively largely, the knee bracket made from an aluminum alloy which can exhibit the required crushing characteristic can be provided. For this reason, in the knee bracket, it is possible to achieve both of ensuring the amount of energy absorption necessary for the passenger's knee collision and applying only a load that does not cause damage to the passenger's knee. Moreover, the use of the aluminum alloy material for the knee bracket is greatly expanded, and the industrial value is great.

It is sectional drawing which shows the one aspect | mode of a knee bracket. It is sectional drawing which shows the deformation | transformation state of the knee bracket of FIG. It is a perspective view which shows the attachment aspect of a knee bracket. FIG. 4 is a cross-sectional view of FIG. 3. It is sectional drawing which shows the time-dependent change of the deformation | transformation by analysis of invention example knee bracket. It is explanatory drawing which shows the load-displacement relationship of FIG. It is sectional drawing which shows the time-dependent change of the deformation | transformation by the analysis of a comparative example knee bracket. It is explanatory drawing which shows the load-displacement relationship of FIG.

Explanation of symbols

1: knee bracket, 2, 3: face plate, 4, 5, 6, 7: plate rib, 8, 10: end plate, 9: flange, 11, 12: bending point, 13: virtual connecting line, 14: push-in Direction, 20: instrument panel occupant, 30: knee panel, 40: dash box, 50: occupant, 51: knee, 60-: mechanical joining means,

Claims (5)

A knee bracket, which is disposed in front of a front seat in an automobile compartment and has the following requirements a to f .
a. The knee bracket is made of a single aluminum alloy extruded hollow member, and is arranged such that the extrusion direction of the extruded member is the vehicle body width direction.
b. This single aluminum alloy extruded hollow member is composed of at least a pair of face plates and a plurality of plate-like ribs connecting the face plates.
c. The ends of the pair of face plates on the rear side of the vehicle body are fixed to a knee panel facing the occupant's knees as load points, while the ends of the pair of face plates on the vehicle body front side are fixed to the vehicle body. It is a supporting point.
d. Each of the face plates has a V-shaped or U-shaped cross-sectional shape that is bent downward.
e. Of the face plates, the lower face plate is thinner than the upper face plate.
f. When the occupant's knee collides with the knee panel, the knee bracket is deformed downward by the configuration of d and e.   A virtual connecting line connecting the bending points of the knee bracket in the V-shaped or U-shaped cross-sectional shape of the face plate is perpendicular to the direction of the assumed pushing force of the occupant's knee to the knee panel at the time of a vehicle body collision. The knee bracket according to claim 1, wherein the knee bracket is arranged in the longitudinal direction of the vehicle body so as to be.   The knee bracket according to claim 1 or 2, wherein an extending direction of the pressure receiving portion of the knee panel is inclined from a direction perpendicular to an assumed pushing force direction of the occupant's knee.   The knee bracket according to any one of claims 1 to 3, wherein the knee bracket has a bending degree in a longitudinal direction of the vehicle body that can prevent interference with a dash box disposed on the vehicle body.   A method for protecting a knee of an automobile occupant using the knee bracket according to any one of claims 1 to 4, wherein when the occupant's knee collides with a pressure receiving portion of the knee panel, the knee bracket is deformed downward. A method for protecting the knees of an automobile occupant characterized by mitigating the impact of the occupant's knee collision.

Images