Vehicle occupant protection structure and vehicle occupant protection method

Abstract

A vehicle occupant protection structure for a vehicle, comprising a pair of vehicle body parts (5, 5) arranged on a left side and a right side of a vehicle body, an instrument panel member (12) arranged to extend in a vehicle width direction between the paired vehicle body parts (5, 5), and a pair of connecting pieces (13, 14) arranged at both ends of the instrument panel member (12) in the vehicle width direction and connected to inner walls of the respective vehicle body parts (5, 5), wherein: a steering shaft support profile (16) configured to support a steering shaft (11) is arranged on a part of the instrument panel member (12) that is located on the left side or the right side with respect to a center part of the instrument panel member (12) in the vehicle width direction; a support element (17) to be connected to a vehicle body part (2) other than the paired vehicle body parts (5, 5) is attached to a part of the dashboard element (12) between the steering shaft support profile (16) and the connecting piece (14) on a side remote from that of the steering shaft (11); and a fragile part (20) is formed on an outer peripheral surface of the dashboard element (12) between the steering shaft support profile (16) and the connecting piece (13) on a side near the steering shaft (11) such that a part of the dashboard element (12) between the steering shaft support profile (16) and the connecting piece (13) on a side near the steering shaft (11) in front of the part (Z) of the dashboard element (12) to which the support element (17) is attached is bent by a load input via the connecting piece (13) on a side near the steering shaft (11) in a vehicle body travel direction, the fragile part (20) is arranged only on a surface which lies on a rear side of the vehicle body with respect to a center line running from top to bottom through a cross-sectional center of the dashboard element (12).

Description

TECHNICAL FIELD

[0001] The present invention relates to a structure and a method for protecting a vehicle occupant in a vehicle, comprising a pair of vehicle body parts arranged on the left side and on the right side of a vehicle body and an instrument panel member arranged to extend in the vehicle width direction between the paired vehicle body parts and a pair of connecting pieces provided at both ends of the instrument panel member in the vehicle width direction and connected to the inner walls of the respective vehicle body parts. BACKGROUND TECHNOLOGY

[0002] Generally, in a case where a hinge pillar is crushed or deformed inward due to a rear-end collision of a vehicle, an instrument panel member having one end connected to the hinge pillar is bent toward the vehicle body rear side around a part near a center stay located substantially in a central part of the instrument panel member in the vehicle width direction.

[0003] When the instrument panel member is deformed as described above, a steering shaft supported by the instrument panel member is moved inward in the vehicle width direction, and a steering wheel is also moved inward in the vehicle width direction as the steering shaft is moved. This means that the belted position of a vehicle occupant is shifted inward in the vehicle width direction by an airbag provided in the steering wheel. It is necessary to design the structure of an instrument panel member itself, the attachment structure between an instrument panel member and a peripheral member, and the arrangement of the peripheral members relative to an instrument panel member so as to prevent such a disadvantage while meeting other requirements. However, simply increasing the strength of an instrument panel member may result in an increase in the weight of a vehicle body.Furthermore, modifying the arrangement of peripheral elements in light of design constraints is not easy. In particular, there is a recent requirement to take measures against impact with a pole or a small overlap impact with a vehicle. Thus, there is a need for a technology that enables the improvement of vehicle occupant safety while solving the above-mentioned disadvantage.

[0004] Patent Literature 1 and Patent Literature 2 are known as technical teachings for the safe restraint of a vehicle occupant by an airbag.

[0005] The conventional technique disclosed in Patent Literature 1 is to ensure accurate operation of an airbag device and the like by preventing the forward and upward rotation of a steering wheel during a vehicle frontal collision. However, Patent Literature 1 does not aim to prevent the movement of an instrument panel member and a steering wheel in the vehicle width direction and fails to solve the above drawback.

[0006] The conventional technology disclosed in Patent Literature 2 is provided with a rotating device capable of changing the deployment direction of an airbag. According to this technology, in a vehicle frontal collision, even if the head of a vehicle occupant is displaced in the left-to-right direction (in the vehicle width direction) with respect to the center of a steering wheel, the vehicle occupant's head can be supported by changing the airbag deployment direction in such a direction that the displacement is compensated with the use of the rotating device. However, in Patent Literature 2, a rotating device for changing the airbag deployment direction is indispensable. Therefore, the structure may become complicated.

[0007] Patent Literature 3 relates to a steering column support for supporting a steering column on a dashboard cross member to act as a mounting base portion for the steering column. Patent Literature 4 discloses a reinforcement structure for automobiles, in which cross car beams constituting a reinforcement structure for the instrument panel or the like include an upper cross car beam made of a hollow bar such as a small-diameter straight or multi-curved tube suspended between the left and right front pillars, and at least one lower cross car beam made of a hollow bar such as a small-diameter L-shaped tube. The part of the lower cross car beam closer to the driver's seat is in contact with and welded to the upper cross car beam, and the part of the lower cross car beam not in contact with the upper cross car beam serves as a brace.A steering shaft is attached to the cross-vehicle members in the direction transverse to the cross-vehicle members. A lower cross-vehicle member of a similar shape to the lower cross-vehicle member closer to the driver's seat may also be arranged closer to the passenger seat. DE Patent Literature 5 discloses a hybrid cross-vehicle member for a vehicle, including a metallic cross member with a portion extending in the main direction of the hybrid cross member in the shape of an open groove, the longitudinal edges of which are connected to a plastic structural member in one portion, preferably by an adhesive seam. Patent Literature 6 discloses a steering element structure capable of developing optimal strength response characteristics by controlling the rigidity of a vehicle body at the time of a collision with a steering element.A steering element structure includes a steering element extending in the width direction of a vehicle and supporting a steering column, and a bracket supporting a lateral end portion of the steering element and having a base end portion attached to a front pillar. The steering element is designed to be displaceable in the axial direction relative to the bracket and, in the event of a frontal impact, performs an axial displacement inward in the width direction of the vehicle relative to the bracket. Patent Literature 7 discloses. Patent Literatures 6 and 7 disclose predetermined bending points of a cross member. LITERATURE CITED PATENT LITERATURE Patent literature 1: JP Hei 8-113 148 A Patent literature 2: JP 2010- 179 674 A Patent literature 3: DE 10 2007 002 431 B4 Patent literature 4: DE 10 2004 010 872 A1 Patent literature 5: DE 103 60 045 A1 Patent literature 6: JP 2000-344 139 A Patent Literature 7: JP S64-25 968 U SUMMARY OF THE INVENTION

[0008] In view of the above disadvantages inherent in the conventional art, an object of the invention is to provide a configuration which enables, with a simplified structure, to suppress the movement of a steering wheel inward in the vehicle width direction to thereby securely restrain a vehicle occupant by an airbag.

[0009] The object is achieved by a vehicle occupant structure having the features of claim 1 and by a vehicle occupant protection method having the features of claim 3. A preferred embodiment is subject matter of dependent claim 2. A vehicle occupant protection structure of the invention for realizing the above object is applied to a vehicle comprising a pair of vehicle body parts arranged on a left side and a right side of a vehicle body, an instrument panel member arranged to extend in a vehicle width direction between the paired vehicle body parts, and a pair of connecting pieces arranged at both ends of the instrument panel member in the vehicle width direction and connected to inner walls of the respective vehicle body parts.In the vehicle occupant protection structure, a steering shaft support profile for supporting a steering shaft is configured at a part of the instrument panel member on the left side or right side with respect to a central part of the instrument panel member in the vehicle width direction. The strength of the instrument panel member at a part thereof between the steering shaft support profile and the connecting piece on a side near the steering shaft is lower than a strength of the instrument panel member at a part thereof between the steering shaft support profile and the connecting piece at an end spaced from the steering shaft with respect to the input of a load via the connecting piece on the side near the steering shaft from the front to the rear in a vehicle body direction.

[0010] According to the invention, in a vehicle frontal collision, the portion of the dashboard element between the steering shaft support profile and the connecting piece on the side near the steering shaft is bent first. Therefore, the above configuration is advantageous in suppressing the inward movement of the steering wheel in the vehicle width direction, thereby safely restraining a vehicle occupant with an airbag. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view illustrating a vehicle occupant protection structure according to an embodiment of the invention; Fig. 2 is an enlarged view showing the essential parts of Fig. 1 explained. Fig. 3 is a bottom plan view illustrating the vehicle occupant protection structure; Fig. 4 is an enlarged view and explains the essential parts of Fig. 3; Fig. 5 is a plan view explaining an operation in a vehicle frontal collision; Fig. 6 is a drawing illustrating a state of a vehicle occupant protection structure according to another embodiment of the invention, viewed from the inside of a vehicle compartment; Fig. 7 is a plan view from below and explains the essential parts of Fig. 7; Fig. 8 is a bottom plan view illustrating another embodiment of the vehicle occupant protection structure; Fig. 9 is a bottom plan view illustrating yet another embodiment of the vehicle occupant protection structure; and Fig. 10 is a bottom plan view illustrating yet another embodiment of the vehicle occupant protection structure. DESCRIPTION OF THE EMBODIMENTS

[0011] In the following, an embodiment of the invention will be described in detail with reference to the drawings. Fig. 1 is a perspective view illustrating a vehicle occupant protection structure of the embodiment. Fig. 2 is a level view and explains essential parts of Fig. 1. In the drawings, arrow F indicates the front of the vehicle body, and arrow R indicates the rear of the vehicle body.

[0012] With reference to Fig. 1 and Fig. 2, a floor panel 1 is provided on a floor surface portion of a vehicle compartment. A tunnel portion 2 is formed integrally with a central portion of the floor panel 1 in the vehicle width direction so as to protrude into the vehicle compartment and extend in the vehicle body traveling direction.

[0013] The tunnel part 2 is formed into a substantially hat-shaped cross-section with left and right side walls 2a and 2b and a top surface 2c. The tunnel part 2 is a primary element configured to reinforce the rigidity of a vehicle body floor part.

[0014] A pair of left and right side sills 3, 3, extending in the vehicle body travel direction, are fixedly connected to the left and right sides of the floor panel 1. The side sill 3 is a vehicle body reinforcement member with a closed cross-section extending in the vehicle body travel direction. The side sill 3 has a side sill inner part and a side sill outer part, which are connected to each other via the closed cross-section.

[0015] With reference to Fig. In Figure 4, reference numeral 18 indicates a steering wheel, and reference numeral 21 indicates an electric power control unit. The steering wheel 18 and the electric power control unit 21 are arranged in front of a driver's seat (not shown). The embodiment is described with the proviso that the vehicle is a left-hand drive vehicle, and the driver's seat is provided at the position on the left side of the passenger compartment.

[0016] As in Fig. 2, a vehicle body side surface is formed with an opening that allows a front seat occupant to get in and out of the vehicle and an opening that allows a rear seat occupant to get in and out of the vehicle. A center pillar 4 extending in the top-down direction is provided between the openings. A lower end of the center pillar 4 is connected to the side sill 3. The center pillar 4 is a vehicle body reinforcement member having a closed cross-section that extends in the top-down direction with respect to the vehicle body. The center pillar 4 includes a center pillar inner part and a center pillar outer part that are connected to each other across the closed cross-section.

[0017] How to continue in Fig. 1 and Fig. As explained in FIG. 2, a hinge pillar 5 rising upward from the side sill 3 is formed at a front end of each of the left and right pairs of side sills 3, 3. The left and right pairs of hinge pillars 5, 5 are vehicle body reinforcement members with a closed cross-section 8 extending from top to bottom toward the vehicle body. The hinge pillar 5 includes a hinge pillar inner portion 6 and a hinge pillar outer portion 6 connected to each other via the closed cross-section 8.

[0018] The support surfaces 9, 9 for receiving a vehicle body side door hinge bracket (not explained) configured to open and close a front door are formed on a vehicle outer surface of the hinge pillar outer part 7. The support surfaces 9, 9 are formed to rise integrally from the vehicle outer surface of the hinge pillar outer part 7.

[0019] As continued in Fig. As shown in Figure 1, an upper portion of the hinge pillar 5 is connected to a lower end of a front pillar 10 extending upward and rearward from the hinge pillar 5. The front pillar 10 is a vehicle reinforcement member with a closed cross-section extending rearward and upward at an inclination. The front pillar 10 includes a front pillar inner portion and a front pillar outer portion connected to each other across the closed cross-section.

[0020] An instrument panel member 12 made of a metal pipe and configured to support a steering shaft 11 is arranged to extend in the vehicle width direction between the hinge pillars 5, 5 as a pair of left and right vehicle body members.

[0021] In this embodiment, the instrument panel member 12 has a large-diameter portion 12A formed on the driver's seat side (left side) and a smaller-diameter portion 12B formed on the passenger seat side (right side). Instrument panel side brackets 13, 14 are provided at both ends of the instrument panel member 12 in the vehicle width direction. The instrument panel side brackets 13, 14 are respectively connected to the hinge pillar inner parts 6, 6 as inner walls of the hinge pillars 5, 5 (vehicle body members). The instrument panel side brackets 13, 14 correspond to a pair of connecting pieces. Both ends of the instrument panel member 12 in the vehicle width direction are connected to the left and right pairs of hinge pillars 5, 5 via the instrument panel side brackets 13, 14.

[0022] As in Fig. 3 and Fig. 4, the side dashboard brackets 13, 14 have tubular parts 13a, 14a to be connected to both ends of the dashboard member and connecting flange parts 13b, 14b to be connected to the hinge pillar inner parts 6, 6.

[0023] As shown schematically in the bottom plan view of a control support structure in Fig. 3, the steering shaft 11 is supported on the large diameter part 12A of the instrument panel member 12 via a steering support bracket 15.

[0024] As in Fig. 4, which shows an enlarged view of the essential parts of Fig. 3, the control bracket 15 comprises a pair of left and right side brackets 15A, 15B having a C-shaped cross section and fixedly connected to the instrument panel member 12, a front bracket 15F that connects the front upper parts of the left and right pairs of side brackets 15A, 15B in the vehicle width direction, and a rear bracket 15R that connects the rear upper parts of the left and right pairs of side brackets 15A, 15B in the vehicle width direction. Referring to Fig. 4 The arrow IN means inside in the vehicle width direction, and the arrow OUT means outside in the vehicle width direction.

[0025] As described above, the steering shaft 11 is supported on the instrument panel member 12 via the steering support bracket 15. Accordingly, a part of the steering support bracket 15 to be fixed to the instrument panel member 12, particularly a center portion of the steering support bracket 15 in the vehicle width direction, will hereinafter be referred to as a steering shaft support member 16. The steering shaft support member 16 is formed at a position closer to the left side than the center portion of the instrument panel member 12 in the vehicle width direction to correspond to a configuration in which the steering wheel 18 and the steering shaft 11 are provided in front of the driver's seat.

[0026] As in Fig. 1 and Fig. As explained in FIG. 2, the instrument panel 12 is supported on the left side wall 2a of the tunnel part 2 via a center support 17 as a support member, which is fixed between the steering shaft support member 16 and the side instrument panel bracket 14 (a connecting piece) on the side spaced from the vehicle steering shaft. In other words, not only are both the left and right ends of the instrument panel 12 connected to the hinge pillars 5, 5 (a pair of vehicle body members) via the side instrument panel brackets 13, 14, but also an intermediate portion of the instrument panel 12 in the vehicle width direction is connected to the tunnel part 2 (another vehicle body member) via the center support 17, thereby fixing the instrument panel 12 between the left and right hinge pillars 5, 5.

[0027] The steering shaft 11 is rotatably supported on the dashboard member 12, which is rigidly fixed to the vehicle body, as described above, via the steering support bracket 15 and a steering column. Furthermore, the steering wheel 18, for allowing the driver to steer the front wheels, is attached to the rear end of the steering shaft 11.

[0028] The steering wheel 18 is equipped with a front airbag device for a driver's seat. The front airbag device has an airbag 19 ( Fig. 5) as a bag body configured to deploy to cover the steering wheel 18 upon vehicle frontal impact.

[0029] In this embodiment, assuming that a small overlap impact occurs at the front of the vehicle body, a hinge pillar 5 on the side (on the left side in this embodiment) near the steering shaft is pressed toward the rear of the vehicle body. When the hinge pillar 5 is pressed, a load in the vehicle body traveling direction is applied via the instrument panel side brackets 13 on the side near the steering shaft 11. In this embodiment, the following configuration is adopted to prevent the steering wheel 18 from moving inward in the vehicle width direction due to the applied load.

[0030] In particular, the strength of the dashboard element 12 at a part thereof (which is indicated by X in Fig. 2) between the steering shaft support profile 16 and the side dashboard bracket 13 on the side near the steering shaft is specified to be lower than the strength of the dashboard element 12 at a part thereof (which is indicated by Y in Fig. 2) between the steering shaft support profile 16 and the side dashboard bracket 14 on the side spaced from the steering shaft 11 with respect to the input load.

[0031] In particular, a strength difference of the dashboard member 12 is predetermined such that a part of the dashboard member 12 between the steering shaft support member 16 and the dashboard side bracket 13 on the side near the steering shaft 11 before a part of the dashboard member 12 to which the center support 17 is attached is bent by the load input via the dashboard side bracket 13 on the side near the steering shaft 11 in the vehicle body traveling direction at the time of impact with a small overlap.

[0032] In other words, the strength in area X is specified to be lower than the strength in area Y, so that the part of the dashboard element 12 corresponding to area X in Fig. 2, in front of a fastening part Z of the central support 17 (in Fig. 2) is bent by the input load in the event of an impact with a small overlap.

[0033] Specifically, in this embodiment, a hole portion 20 is formed as a fragile portion in a portion (any portion within the X region) of the instrument panel member 12 between the steering shaft support profile 16 and the side instrument panel bracket 13 on the side near the steering shaft to ensure the aforementioned strength difference. The presence of the hole portion 20 makes the portion corresponding to the X region fragile.

[0034] Preferably, the hole part 20 (a fragile part) may be formed in one of the positions selected from an upper part, a lower part, and a rear part of an outer peripheral part of the instrument panel member 12. In other words, assuming that the instrument panel member 12 is divided into two parts by a center line passing through a cross-sectional center of the instrument panel member 12 from top to bottom and extending downward in the vehicle direction from the vehicle body, the entire part 20 may preferably be formed in a rear side region corresponding to the vehicle body rear side with respect to the center line, rather than in a front side region corresponding to the vehicle body front side with respect to the center line. In this embodiment, as shown in Fig. 1 to Fig. 4, the hole portion 20 is formed to penetrate a lower portion of the large-diameter portion 12A of the instrument panel member 12. Thus, the hole portion 20 (a fragile portion) is formed in the lower portion 20 of the outer peripheral portion of the instrument panel member 12.

[0035] The following describes an operation based on the configuration of this embodiment.

[0036] The instrument panel member 12 is supported on the center support 17 as a support member. Therefore, in the case where a vehicle frontal collision, particularly a small overlap collision (an accident such that a vehicle collides with an obstacle P such as a pole at a position on the vehicle outer side as a pair of left and right front side frames FS provided on the vehicle body front part), has occurred as shown in Fig. 5, the position of the steering wheel 18 may be greatly shifted in the vehicle width direction if no measure is taken. For example, assume that an impact such as the aforementioned small overlap impact occurs in a conventional structure without a hole part 20 as a fragile part. In such a case, a hinge pillar may be bent rearward by an obstacle, and a large bending moment may act on an instrument panel. As a result, the instrument panel may be bent and deformed around a mounting part of a center pillar. When such deformation occurs, a part of the instrument panel between the mounting part and the center pillar and a left-side instrument panel side bracket may be greatly displaced toward the rear of the vehicle body.Accordingly, the rear part of a steering shaft and a steering wheel can be moved inward in the vehicle width direction. There is an idea of ​​increasing the strength of a dashboard element to prevent such an incident. However, this idea may lead to an increase in the weight of a vehicle body. Another idea involves modifying the attachment structure between a dashboard element and peripheral elements, as well as the arrangement of the peripheral elements. However, this idea is not easy to implement due to design constraints.

[0037] In contrast, a relatively simple structure of forming the hole part 20 as a fragile part makes it possible to suppress the movement of the steering wheel 18 in the vehicle width direction in a vehicle frontal collision, especially in a small overlap collision. Specifically, in the structure of this embodiment, when a vehicle collides with an obstacle P such as a pole at a position on the outer side of the left front frame FS in the vehicle width direction, a shock absorber (not explained) or the like on the vehicle body front surface may break due to the collision with an obstacle P.Thereafter, a part around the left end of a shock absorber reinforcement BR in the vehicle width direction may come into contact with the obstacle P, and a front wheel FW may be pushed toward the vehicle body rear by the obstacle P, with the result that the front wheel FW may push the hinge pillar 5 toward the vehicle body rear. In this way, also in the structure of this embodiment, the hinge pillar 5 can be bent rearward, just like the conventional structure described above. In the embodiment, however, even if the hinge pillar 5 is bent rearward, the instrument panel member 12 is bent around the hole part 20 as shown by the imaginary line α in FIG. Fig. 5. Therefore, the deformation amount of the steering shaft support profile 16 of the instrument panel member 12 in the inward direction of the vehicle width direction is as shown by the imaginary line β1 in Fig. 5. The amount of deformation of the steering shaft support profile 16, as illustrated by the imaginary line β1, is small compared to the amount of deformation in the case where the instrument panel member 12 is deformed around the movable part of the central support 17. Accordingly, the amounts of deformation of the rear part of the steering wheel 18 and the airbag 19 in the vehicle width direction inward are also very small, as illustrated by the imaginary line β2 in Fig. 5 explained.

[0038] In other words, in the structure of the embodiment, the instrument panel member 12 is first bent at a portion thereof between the steering shaft support profile 16 and the side instrument panel bracket on the side near the steering shaft 11 around the hole portion 20 in a small overlap impact. Therefore, the movement of the steering shaft 11 and the steering wheel 18 inward in the vehicle width direction is prevented (see imaginary line β2 in Fig. 5), it is possible to safely restrain a passenger (a passenger as shown by the imaginary line β3, who tends to bend forward due to inertia upon impact) by the airbag 19 deployed from the steering wheel 18.

[0039] As described above, the vehicle occupant protection structure of the Fig. 1 to Fig. 5 is applied to a vehicle including the left and right pair of hinge pillars 5, 5 (vehicle body parts), the instrument panel member 12 arranged to extend in the vehicle width direction between the pair of hinge pillars 5, 5 and the pair of instrument panel side brackets 13, 14 (connecting pieces) arranged at both ends of the instrument panel member 12 in the vehicle width direction and connected to the hinge pillar inner parts 6, 6 (inner walls of the vehicle body parts) of the respective hinge pillars 5, 5. The vehicle occupant protection structure is configured so that the strength of the instrument panel member 12 at a part thereof (area X explained in Fig. 2) between the steering shaft support profile 16 and the side dashboard bracket 13 on the side (driver's seat side near the steering shaft 11) is specified to be lower than the strength of the dashboard element 12 at a part thereof (area Y, which is in Fig. 2) between the steering shaft support profile 16 and the side dashboard bracket 14 on the side spaced from the steering shaft 11 (driver's seat side), with respect to a load input by the dashboard side bracket 13 on the side near the steering shaft 11 in the vehicle body travel direction.

[0040] According to the above configuration, a part (a part of the instrument panel member whose strength is low) of the instrument panel member 12 between the steering shaft support profile 16 and the side instrument panel bracket 13 on the side near the steering shaft 11 is bent first in a vehicle frontal collision, especially in a small overlap collision. Therefore, the inward movement of the rear part of the steering shaft 11 and the steering wheel 18 in the vehicle width direction is suppressed, making it possible to securely restrain the vehicle occupant DR (especially the head and chest of the vehicle occupant) by the airbag 19 deployed from the steering wheel 18.

[0041] In this embodiment, a center stay 17 (a support member) connected to the tunnel part 2 (another vehicle body part) on the vehicle body floor part is fixed to a part of the instrument panel member 12 between the steering shaft support profile 16 and the instrument panel side bracket 14 on the side spaced from the steering shaft 11. The mounting part Z of the center stay 17 is spaced from a part of the instrument panel member 12 (i.e., the instrument panel side bracket 13 on the side near the steering shaft 11), whereby a load is introduced during a small overlap collision and stress tends to concentrate at the mounting part Z. Accordingly, it is considered that the instrument panel member 12 is likely to be bent around the mounting part Z of the center stay 17 unless measures are taken.However, it is necessary to avoid such an event in order to safely restrain the vehicle occupant DR by the airbag 19, which is deployed by the steering wheel 18.

[0042] In view of the above, the strength difference of the instrument panel member 12 is adjusted so that the instrument panel member 12 at a part thereof (the area X explained in Fig. 2) between the steering shaft support profile 16 and the dashboard side bracket 13 on the side near the steering shaft 11 in front of the dashboard element 12 at a part thereof (the mounting part Z) to which the center support 17 is attached, is bent by the load input through the dashboard side bracket 13 on the side near the steering shaft 11 in the vehicle body traveling direction.

[0043] According to the above configuration, the part of the instrument panel 12 between the steering shaft support profile 16 and the side instrument panel bracket 13 on the side near the steering shaft 11 is bent forward of the part of the instrument panel 12 to which the center support 17 is attached. This is advantageous for effectively preventing deformation of the instrument panel 12 around the mounting part Z of the center support 17 and securely preventing the steering shaft 11 and the steering wheel 18 from moving inward in the vehicle width direction.

[0044] Furthermore, in this embodiment, the hole part 20 as a fragile part is formed in a part of the instrument panel member 12 between the steering shaft support profile 16 and the side instrument panel bracket 13 on the side near the steering shaft 11.

[0045] According to the above configuration, it is possible to obtain the aforementioned effects with a simplified configuration.

[0046] In addition to the above, in this embodiment, the hole part 20 is formed in an outer peripheral part (specifically, in a lower part of the outer peripheral part) of the instrument panel member 12, which is located on the vehicle body rear side with respect to the center line passing through the cross-sectional center of the instrument panel member 12 in the top-down direction (see Fig. 4), trained.

[0047] As above, in the case where the hole portion 20 is formed at a position in a rear region of an outer peripheral part of the instrument panel member 12, it is possible to securely bend the instrument panel member 12 toward the rear of the vehicle body in a vehicle frontal collision. Therefore, the above configuration is advantageous in preventing the steering shaft 11 and the steering wheel 18 from moving inward in the vehicle width direction, thereby securely restraining the vehicle occupant DR by the airbag 19.

[0048] Specifically, in this embodiment, the hole portion 20 formed in the instrument panel member 12 serves as a fragile portion. Therefore, it is easy to form a fragile portion by a hole forming method such as a drilling method.

[0049] A fragile part to be formed in the instrument panel member 12 is not limited to the hole part 20 described above, as long as it is possible to reduce the strength. For example, a concave notch part or a reduced-diameter part may be formed as the fragile part. Other embodiments are described in the following examples of forming a fragile part other than the hole part 20.

[0050] Another embodiment of the vehicle occupant protection structure is described with reference to Fig. 6 and Fig. 7 described. Fig. Fig. 6 is an explanatory drawing explaining a state of the inside of a vehicle body viewed from the front side, and Fig. 7 is a bottom plan view of Fig. 6.

[0051] In this embodiment, a concave notch part 22 as a fragile part is formed in a part of an instrument panel member 12 between a steering shaft support profile 16 and an instrument panel side bracket 13 on the side near a steering shaft 11.

[0052] The concave notch portion 22 is formed such that a larger diameter portion 12A of the instrument panel member 12 is curved inward in the radial direction. Specifically, the concave notch portion 22 is integrally formed with a rear surface of an outer peripheral portion of the large diameter portion 12A of the instrument panel member 12, in other words, a rear lateral portion facing toward a vehicle occupant. The concave notch portion 22 is formed to extend within a predetermined range in the circumferential direction of the large diameter portion 12A.

[0053] The structure of a fragile part with concave notch part 22 as described above also makes it possible to form the fragile part by a simplified process of the instrument panel member 12.

[0054] The different configuration, the different operation and the different effect of the embodiment, the Fig. 6 and Fig. 7 are essentially the same as those of the previous embodiment. Accordingly, the same elements are Fig. 6 and Fig. 7 like those in Fig. 1 to Fig. 5 are indicated by the same reference numerals, and a detailed description thereof is omitted herein.

[0055] Fig. 8 is an enlarged bottom plan view illustrating essential parts of yet another embodiment of the vehicle occupant protection structure.

[0056] In this embodiment, a reduced diameter part 23 as a fragile part is integrally formed on a part of an instrument panel member 12 between a steering shaft support profile 16 and an instrument panel side bracket 13 on the side near a steering shaft 11.

[0057] The reduced-diameter part 23 is formed by a process of reducing the diameter of a part of a large-diameter part 12A of the instrument panel member 12. Specifically, a portion of the large-diameter part 12A near the outer side in the vehicle width direction is machined to have an outer diameter smaller than the diameter of the other portion of the large-diameter part 12A, whereby the portion of the large-diameter part 12A near the outer side in the vehicle width direction is formed with a relatively small diameter relative to the inner part of the reduced-diameter part 23. Thus, a step portion with a difference in outer diameter is formed at an inner end (a boundary with respect to the large-diameter part 12A, which is different from the reduced-diameter part 23) of the reduced-diameter part 23 in the vehicle width direction.

[0058] As described above, by constructing a fragile part by the reduced-diameter part 23, the fragile part can also be formed by a simplified process of the instrument panel member 12. In the case where the reduced-diameter part 23 is used as the fragile part, the fragile part is formed over the entire circumference of a certain area of ​​the instrument panel member 12.

[0059] The other configuration, operation and effect of the embodiment described in Fig. 8 are essentially the same as those of the previous embodiments. Therefore, the same elements are shown in Fig. 8 like those in Fig. 1 to Fig. 7 are designated by the same reference numerals, and a detailed description thereof is omitted herein.

[0060] Fig. 9 is an enlarged bottom plan view illustrating essential parts of yet another embodiment of the vehicle occupant protection structure.

[0061] In this embodiment, a thin part 24 as a fragile part is formed on an instrument panel member 12 at a part thereof between a steering shaft support profile 16 and an instrument panel side bracket 13 on the side near a steering shaft 11.

[0062] It is possible to form a thin part by forming an instrument panel from two types of tubular members with different thicknesses. However, in this embodiment, the thin part 24 with a relatively small thickness is formed by grinding a predetermined part (a specific part between the steering shaft support profile 16 and the instrument panel side bracket 13) of the large-diameter part 12A of the instrument panel member 12. The thin part 24 is formed over a predetermined range in the circumferential direction on a rear surface of an outer peripheral part of the large-diameter part 12A.

[0063] As described above, the construction of a fragile part by the thin part 24 also makes it possible to form the fragile part by a simplified process of the instrument panel member 12.

[0064] The other configuration, operation, and effect of the embodiment illustrated in FIG: 9 are substantially the same as those of the previous examples. Accordingly, the same parts are used in Fig. 9 like those in the Fig. 1 to 8 are designated by the same reference numerals, and a detailed description thereof is omitted herein.

[0065] Fig. 10 is an enlarged plan view illustrating essential parts of still another embodiment of the vehicle occupant protection structure.

[0066] In this embodiment, a notch part 25 as a fragile part is formed in a part of an instrument panel member 12 between a steering shaft support profile 16 and an instrument panel side bracket 13 on the side near a steering shaft 11.

[0067] The notch portion 25 is formed by indenting a portion of a rear surface of a large-diameter portion 12A of the instrument panel member 12 in a forward direction (inward in the radial direction). The notch portion 25 is a type of concave notch portion. However, the notch portion 25 is different from the concave notch portion 22 shown in the Fig. 6 and Fig. 7, in that the cross section of the notch portion 25 has a V-shape in cross section. In the case where the notch portion 25 is formed with a V-shape in cross section as described above, the notch portion 25 securely functions as a bending starting point of the instrument panel member 12 in a small overlap impact.

[0068] As described above, the construction of a fragile part by the notch part 25 also makes it possible to form the fragile part by a simplified process of the instrument panel member 12.

[0069] The other configuration, operation and impact of the Fig. 10 are essentially the same as in the above-mentioned embodiments. Accordingly, the same parts are Fig. 10 like those in the Fig. 1 to 9 are designated by the same reference numerals, and a detailed description thereof is omitted herein.

[0070] The preferred embodiments of the invention have been described above. However, the invention is not limited to the configurations of the aforementioned embodiments.

[0071] For example, a fragile part may consist of two or more of the combinations selected from the hole part 20, the concave notch part 22, the reduced diameter part 23, the thin part 24, and the notch part 25.

[0072] Furthermore, the configuration of each embodiment is based on the assumption that the vehicle is a left-hand drive vehicle. Alternatively, the invention can be applied to a right-hand drive vehicle.

[0073] Furthermore, in the aforementioned embodiments, the formation of a fragile part (e.g., the hole part 20, the concave notch part 22, the reduced-diameter part 23, the thin part 24, or the notch part 25) on the instrument panel member 12 allows the instrument panel member 12 to bend at a part between the steering shaft support profile 16 and the side instrument panel bracket 13 (a connecting piece) on the side near the steering shaft 11, in front of the instrument panel member 12, and at a part thereof between the steering shaft support profile 16 and the side instrument panel bracket 14 (a connecting piece) on the part spaced from the steering shaft 11 during a vehicle frontal collision. However, it is possible to configure a part other than the fragile part as far as it is possible to obtain substantially the same effects as described above.

[0074] Finally, a summary of the configurations and advantages of the invention is described based on the disclosure of the embodiments.

[0075] A vehicle occupant protection structure of the invention is applied to a vehicle, including a pair of vehicle body members arranged on a left side and a right side of a vehicle body, an instrument panel member arranged to extend in a vehicle width direction between the pair of vehicle body members, and a pair of connecting pieces arranged at both ends of the instrument panel member in the vehicle width direction and connected to inner walls of the respective vehicle body members. In the vehicle occupant protection structure, a steering shaft support profile configured to support a steering shaft is arranged at a part of the instrument panel member on the left side or the right side with respect to a center part of the instrument panel member in the vehicle width direction.A strength of the dashboard member at a part thereof between the steering shaft support profile and the connecting piece on a side near the steering shaft is specified to be lower than a strength of the dashboard member at a part thereof between the steering shaft support profile and the connecting piece on a side remote from the steering shaft, with respect to a load input through the connecting piece on the side near the steering shaft in a vehicle body travel direction.

[0076] In the invention, the paired vehicle body parts may be hinge pillars, and the inner walls of the vehicle body parts may be hinge pillar inner parts.

[0077] According to the above configuration, in a vehicle frontal collision, especially in a small overlap collision, the part of the instrument panel (a fragile part of the instrument panel that is weak in strength) between the steering shaft support profile and the connecting piece connected to the vehicle body part on the side near the steering shaft is bent first. Therefore, it is possible to suppress the inward movement of the rear part of the steering shaft and the steering wheel in the vehicle width direction, thereby making it possible to safely restrain a vehicle occupant (especially the head and chest of a vehicle occupant) by an airbag deployed from the steering wheel.

[0078] In the vehicle occupant protection structure, in a case where a support member to be connected to a vehicle body part other than the paired vehicle body parts is fixed to the part of the instrument panel member between the steering shaft support profile and the connecting piece on the side spaced from the steering shaft, a strength difference of the instrument panel member may preferably be set such that the part of the instrument panel member between the steering shaft support profile and the connecting piece on the side near the steering shaft is bent before the part of the instrument panel member to which the support member is fixed by the load input via the connecting part on the side near the steering shaft in the vehicle body traveling direction.

[0079] According to the above configuration, the part of the dashboard member between the steering shaft support profile and the connecting piece on the side near the steering shaft is bent forward of the part of the dashboard member to which the support profile is attached. Therefore, the above configuration is advantageous in effectively preventing deformation of the dashboard member around the mounting portion of the support member and securely preventing the steering shaft and steering wheel from moving inward in the vehicle width direction.

[0080] In the vehicle occupant protection structure, a fragile part is preferably formed at the part of the instrument panel member between the steering shaft support profile and the connecting piece on the side close to the steering shaft.

[0081] According to the above configuration, it is possible to obtain the aforementioned effects with a simplified configuration.

[0082] In the vehicle occupant protection structure, the fragile part is formed at an outer peripheral part of the instrument panel member located on a vehicle body rear side with respect to a center line passing through a cross-sectional center of the instrument panel member from top to bottom.

[0083] By positioning the fragile part at the rear of the outer peripheral portion of the instrument panel, it is possible to reliably deflect the instrument panel toward the rear of the vehicle body during a frontal collision. Therefore, the above configuration is effective in reliably preventing the steering shaft and steering wheel from moving inward in the vehicle width direction, thereby safely restraining a vehicle occupant through an airbag.

[0084] In the vehicle occupant protection structure, preferably, the fragile part may be constructed of at least one of a hole part, a concave notch part, or a reduced diameter part formed in the instrument panel member.

[0085] According to the above configuration, it is possible to construct the fragile part by one or two or more combinations of the hole part, the concave notch part, and the reduced diameter part, and it is possible to form the hole part, the concave notch part, and the reduced diameter part with a simplified process of the instrument panel member.

[0086] Furthermore, the invention relates to a vehicle occupant protection method for a vehicle, comprising a pair of vehicle body parts arranged on a left side and a right side of a vehicle body, an instrument panel member arranged to extend in a vehicle width direction between the paired vehicle body parts, a pair of connecting pieces arranged at both ends of the instrument panel member in the vehicle width direction and connected to inner walls of the respective vehicle body parts, a steering shaft support profile arranged on a part of the instrument panel member located on the left side or the right side with respect to a central part of the instrument panel member in the vehicle width direction for supporting a steering shaft, a steering wheel mounted on a rear end of the steering shaft, and an airbag,which is provided in the steering wheel and configured to be deposited in such a way as to cover the steering wheel during a vehicle frontal collision. The method comprises varying a rigidity of the steering shaft depending on a position thereof in the vehicle width direction in such a way that the instrument panel member is bent at a portion thereof between the steering shaft support profile and the connecting piece on a side near the steering shaft in front of the instrument panel member at a portion thereof between the steering shaft support profile and the connecting piece on a side spaced from the steering shaft by a load input through the connecting piece on the side near the steering shaft in a vehicle body rearward direction at the time of the vehicle frontal collision.

[0087] According to the above method, it is possible to suppress the inward movement of the deployed airbag in the vehicle width direction, thereby safely restraining a vehicle occupant. INDUSTRIAL APPLICATION POSSIBILITIES

[0088] As described above, the invention is suitably used for protecting a vehicle occupant in a vehicle comprising a pair of vehicle body parts arranged on the left side and the right side of a vehicle body, an instrument panel member arranged to extend in the vehicle width direction between the paired vehicle body parts, and a pair of connecting pieces arranged at both ends of the instrument panel member in the vehicle width direction and connected to inner walls of the respective vehicle body parts.

Claims

[1] A vehicle occupant protection structure for a vehicle, comprising a pair of vehicle body parts (5, 5) arranged on a left side and a right side of a vehicle body, an instrument panel member (12) arranged to extend in a vehicle width direction between the paired vehicle body parts (5, 5), and a pair of connecting pieces (13, 14) arranged at both ends of the instrument panel member (12) in the vehicle width direction and connected to inner walls of the respective vehicle body parts (5, 5), wherein: a steering shaft support profile (16) configured to support a steering shaft (11) is arranged on a part of the instrument panel member (12) that is located on the left side or the right side with respect to a center part of the instrument panel member (12) in the vehicle width direction; a support element (17) to be connected to a vehicle body part (2) other than the paired vehicle body parts (5, 5) is attached to a part of the dashboard element (12) between the steering shaft support profile (16) and the connecting piece (14) on a side remote from that of the steering shaft (11); and a fragile part (20) is formed on an outer peripheral surface of the dashboard element (12) between the steering shaft support profile (16) and the connecting piece (13) on a side near the steering shaft (11) such that a part of the dashboard element (12) between the steering shaft support profile (16) and the connecting piece (13) on a side near the steering shaft (11) in front of the part (Z) of the dashboard element (12) to which the support element (17) is attached is bent by a load input via the connecting piece (13) on a side near the steering shaft (11) in a vehicle body travel direction, the fragile part (20) is arranged only on a surface which lies on a rear side of the vehicle body with respect to a center line running from top to bottom through a cross-sectional center of the dashboard element (12). [2] The vehicle occupant protection structure according to claim 1, wherein the fragile part (20) consists of at least one of a hole part, a concave notch part, or a thin part formed in the instrument panel member (12). [3] A vehicle occupant protection method for a vehicle comprising a pair of vehicle body parts (5, 5) arranged on a left side and a right side of a vehicle body, an instrument panel member (12) arranged to extend in a vehicle width direction between the paired vehicle body parts (5, 5), a pair of connecting pieces (13, 14) arranged at both ends of the instrument panel member (12) in the vehicle width direction and connected to inner walls of the respective vehicle body parts (5, 5), a steering shaft support profile (16) arranged at a part of the instrument panel member (12) located on the left side or the right side with respect to a central part of the instrument panel member (12) in the vehicle width direction, for supporting a steering shaft (11), a steering wheel (18) fixed to a rear end of the steering shaft (11), and an airbag,provided in the steering wheel (18) and configured to be deployed to cover the steering wheel (18) at the time of a vehicle frontal impact, the method comprising: Forming a fragile part (20) on an outer peripheral surface of the dashboard element (12) between the steering shaft support profile (16) and the connecting piece (13) on a side near the steering shaft (11) in such a way that the dashboard element (12) is bent at a part (Z) thereof between the steering shaft support profile (16) and the connecting piece (13) on the side near the steering shaft (11) before the part (Z) of the dashboard element (12) at a part thereof between the steering shaft support profile (16) and the connecting piece (14) on a side remote from the steering shaft (11) by a load input via the connecting piece (13) on the side near the steering shaft (11) in a vehicle body travel direction in a frontal impact, wherein the fragile part (20) is arranged only on one surface,which lies on a rear side of the vehicle body with respect to a center line running from top to bottom through a cross-sectional center of the dashboard element (12).

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