JP7765725B2 - Steering support structure - Google Patents

Description

The present invention relates to a steering support structure that is installed in the upper front part of a vehicle's interior and supports a steering column, etc.

Conventionally, a cylindrical lateral strength member extends in the vehicle width direction behind a body panel, such as a dash panel, at the front of the vehicle to support a steering column or other components. In a steering support structure (also called a steering support member) that includes a lateral strength member, a steering column support hanger extends from the lateral strength member toward the front of the vehicle, and the steering column is supported via the steering column support hanger. A connecting member is provided between the lateral strength member and the body panel, and the lateral strength member and the body panel are connected via the connecting member.

One example of a steering support structure is the rigid support structure disclosed in Patent Document 1. The rigid support structure includes a vehicle body strength member that extends in the vehicle width direction behind the front wall of the vehicle interior, and a rigid support member that connects the front wall of the vehicle interior to the vehicle body strength member. A deformation starting point formed by a notch is provided in the upper reinforcing flange of the rigid support member. When an impact load is input from the front of the vehicle, the rigid support member bends and deforms starting from the deformation starting point, thereby absorbing the energy of the impact load.

JP 2014-125140 A

In order to improve the protection performance for occupants in the vehicle cabin, it may be necessary to absorb the energy of an impact load input from the front of the vehicle gradually (i.e., in stages). In at least this respect, there is room for improvement in the rigid support structure of Patent Document 1.

The present invention therefore aims to provide a steering support structure that can gradually absorb the energy of an impact load input from the front of the vehicle.

To achieve the above-mentioned objective, one aspect of the present invention provides a steering support structure including a lateral strength member extending in the vehicle width direction behind a body panel on the front side of the vehicle, a connecting member connecting the lateral strength member to the body panel, and a steering column support hanger extending from the lateral strength member to the front of the vehicle below the connecting member. In this steering support structure, the connecting member includes a rigidity retention portion, an overall deformation portion, and a front deformation portion. The rigidity retention portion extends from the lateral strength member to the front of the vehicle and is located above the steering column support hanger. The overall deformation portion has a front connection portion connected to the body panel, a first rear connection portion connected to the steering column support hanger, and a second rear connection portion connected to the rigidity retention portion, and forms a structure that runs around via the front connection portion, the first rear connection portion, and the second rear connection portion and is open in the vehicle width direction. The front deformation portion has a main vertical member extending in the vehicle's vertical direction inside the overall deformation portion, and the main vertical member and a portion of the overall deformation portion forward of the main vertical member form a structure that is open in the vehicle's width direction. The upper portion of the overall deformation portion that constitutes part of the front deformation portion extends linearly in the vehicle's fore-and-aft direction, and the lower portion of the overall deformation portion extends in a bent shape at the first rear connection portion, and the main vertical member extends upward from a predetermined position between the front connection portion and the first rear connection portion of the overall deformation portion. The front deformation portion has a weak portion in the extension that extends linearly in the vehicle's fore-and-aft direction between the front connection portion and the upper end of the main vertical member.

In the steering support structure according to the above embodiment, both the overall deformation portion and the front deformation portion are structural bodies that open in the vehicle width direction. Therefore, each deformation portion can be easily formed to (1) ensure sufficient rigidity under normal conditions, while (2) have the strength to tolerate deformation in the direction of the impact load when an impact load is applied to the front connection portion from the front of the vehicle toward the rear of the vehicle. Furthermore, the portion of the overall deformation portion above the vehicle that constitutes part of the front deformation portion extends linearly in the fore-and-aft direction of the vehicle, while the portion below the vehicle extends in a bent shape at the first rear connection portion, resulting in a downward slope between the front connection portion and the first rear connection portion toward the rear of the vehicle. Therefore, when an impact load is applied to the front connection portion, bending deformation is induced in the overall deformation portion, primarily originating from the first rear connection portion, while the overall deformation portion is firmly supported from the rear of the vehicle by the steering column support hanger and the rigidity retaining portion. As a result, the overall deformation portion is designed to deform overall when an impact load is applied, causing the front connection portion to move upward and rearward. Meanwhile, in the front deformation portion, the weak portion is located in the extension that extends linearly in the fore-and-aft direction of the vehicle, which is where impact loads are easily transmitted. This means that deformation originating primarily from the weak portion is more actively induced than bending deformation of the first rear connection portion.

Here, the impact load input to the front connection portion is transmitted to the weak portion and the first rear connection portion, respectively. As a result, in the early stages after the impact load is input, deformation of the front deformation portion (hereinafter referred to as "front deformation") originating from the weak portion and overall deformation of the overall deformation portion (hereinafter referred to as "overall deformation") originating from the first rear connection portion occur simultaneously, and the front deformation and overall deformation overlap in the front deformation portion. However, due to the mechanical characteristics of the structure, whereby force flows all at once into a weak point where deformation has progressed (i.e., concentrated load occurs), once the front deformation has progressed to a certain extent, the force that was inducing overall deformation also flows into the weak portion, and most of the impact load input to the front connection portion flows all at once into the weak portion. As a result, overall deformation is suppressed and almost ceases to occur, and front deformation becomes dominant. Because the connecting member deforms through the above-described deformation process, in the early stages after an impact load is input, part of the energy of the input impact load is consumed by both the front deformation and the overall deformation and is rapidly absorbed. Thereafter, once the front deformation has progressed to a certain extent, most of the remaining energy of the impact load is consumed by the energy for the front deformation and is slowly absorbed. In this way, the deformation of the front deformation portion (front deformation) continues longer than the deformation of the overall deformation portion (overall deformation), and due to the difference in the duration of each deformation, the energy of the input impact load is absorbed gradually, or in stages, over time.

In this way, the present invention provides a steering support structure that can gradually absorb the energy of an impact load input from the front of the vehicle.

1 is a side view of a main part including a connecting member of a steering support structure according to an embodiment of the present invention, viewed from the vehicle width direction. FIG. 4 is a perspective view of the main part as viewed from another angle. FIG. 4 is a perspective view of the main part as viewed from another angle. FIG. 5A to 5C are conceptual diagrams for explaining a deformation process of the connecting member. 5A and 5B are conceptual diagrams for explaining a process of absorbing energy of an impact load input to the connecting member.

Embodiments of the present invention will now be described with reference to the accompanying drawings. Figures 1 to 4 are diagrams illustrating a steering support structure 100 according to one embodiment of the present invention, with Figure 1 being a side view of the essential parts as viewed from the vehicle width direction, Figure 2 being a top view of the essential parts as viewed from above the vehicle, Figure 3 being a perspective view of the essential parts as viewed from the front of the vehicle, and Figure 4 being a perspective view of the essential parts as viewed from a different angle. Note that Figure 1 is also a cross-sectional view taken along line A-A in Figure 3. In the figures, the arrow Fr direction indicates the front of the vehicle in the vehicle's fore-and-aft direction, the arrow O direction indicates the outside of the vehicle in the vehicle width direction, and the arrow U direction indicates the top of the vehicle in the vehicle's up-and-down direction.

[Outline of steering support structure]
1 and 2, the cabin of a vehicle such as an automobile is defined by a body panel 1 such as a dash panel at the front side of the vehicle. A steering support structure 100 is provided behind the body panel 1 at the front side of the vehicle. The steering support structure 100 is disposed inside an instrument panel (not shown) and supports the instrument panel, as well as a steering column (not shown) and the like on the driver's seat side.

As shown in Figures 1 to 4, the steering support structure 100 comprises a lateral strength member 10, a connecting member 20, and a steering column support hanger 30. The connecting member 20 and the steering column support hanger 30 are provided on the driver's seat side. The steering support structure 100 is also called a steering support member.

The lateral strength member 10 is a member that extends in the vehicle width direction behind the body panel 1. The lateral strength member 10 is made of, for example, a cylindrical metal pipe that extends across the entire width of the vehicle. Both ends of the lateral strength member 10 in the vehicle width direction are fixed to dash side panels that constitute the sides of the vehicle body (not shown).

A reinforcing member 12, made of a rectangular tubular metal pipe shorter than the lateral strength member 10, extends in the vehicle width direction behind the driver's seat side (i.e., the steering column side, not shown). Both ends of the reinforcing member 12 in the vehicle width direction are fixed to rear brackets 13 (see Figure 3) that extend rearward from the lateral strength member 10. One rear bracket 13 is shown in Figure 3; the other rear bracket 13 is located outside the illustrated range and is not shown. The rear bracket 13 extends in an upwardly sloping direction toward the rear of the vehicle. The rectangular tubular reinforcing member 12 is inclined to match the rear bracket 13, as shown in Figure 3. Two lower brackets 14, 14 are positioned below the lateral strength member 10 and reinforcing member 12, spaced apart in the vehicle width direction. Each lower bracket 14 connects the lateral strength member 10 and reinforcing member 12.

The connecting member 20 connects the transverse strength member 10 to the body panel 1 and is made of steel plate. The connecting member 20 is formed, for example, by welding multiple press-molded components together. The connecting member 20 protrudes from the upper portion of the transverse strength member 10 toward the front of the vehicle. Specifically, the rear end of the connecting member 20 in the vehicle's fore-and-aft direction is fixed (connected) by welding to the transverse strength member 10 and the reinforcing member 12, while the front end of the connecting member 20 in the vehicle's fore-and-aft direction is fastened (connected) to the body panel 1 with appropriate fasteners 15 (here, bolts). In this way, the connecting member 20 connects the transverse strength member 10 and the reinforcing member 12 to the body panel 1. The connecting member 20 is also fixed (connected) by welding to the steering column support hanger 30, as described below. The detailed structure of the connecting member 20 will be described later.

The steering column support hanger 30 is a member that extends from the lateral strength member 10 toward the front of the vehicle below the connecting member 20. The steering column is positioned below the steering column support hanger 30. The steering column support hanger 30 is a highly rigid member that primarily supports (holds) the steering column from above, and is designed to be able to firmly hold components including the steering column, as well as to have sufficient rigidity to withstand collision loads that may be input from the front of the vehicle.

The steering column support hanger 30 is made of, for example, steel plate and includes a hanger main body 31 with a U-shaped cross section that opens toward the underside of the vehicle, and a hanger front wall 32 that closes the opening of the hanger main body 31 at the front of the vehicle. The hanger front wall 32 has an inclined surface 32a that connects to and supports the lower rear corner of the connecting member 20 (the first rear connection portion 22a described below). In other words, the steering column support hanger 30 also supports the connecting member 20. The rear end of the steering column support hanger 30 in the vehicle's fore-and-aft direction is welded to the transverse strength member 10, and the front end of the steering column support hanger 30 in the vehicle's fore-and-aft direction (hanger front wall 32) is welded to the lower rear corner of the connecting member 20 (the first rear connection portion 22a). The steering column support hanger 30 extends in a direction that slopes downward from the front of the transverse strength member 10 toward the front of the vehicle. Additionally, when viewed in the vehicle width direction, the lateral strength member 10 is located between the reinforcing member 12 and the rear bracket 13 and the steering column support hanger 30.

[Details of the rear body structure]
In order to improve the protection performance for occupants in the vehicle cabin, when absorbing the energy of an impact load that may be input from the front of the vehicle, it may be necessary to absorb this energy gradually over time (i.e., in stages). In response to this, the steering support structure 100 according to this embodiment has the following structure.

As shown in FIG. 1, the connecting member 20, when divided primarily in terms of deformation due to impact load, comprises a rigidity-retaining portion 21, an overall deformation portion 22, and a front deformation portion 23. In FIG. 1, the extent of the overall deformation portion 22 is indicated by a two-dot chain line, and the extent of the front deformation portion 23 is indicated by a single-dot chain line. Furthermore, the connecting member 20 is formed by welding multiple molded parts together. When divided in terms of the individual molded parts before joining, the connecting member 20 is a component consisting of a tip patch 20A to which an impact load is input from the front of the vehicle (body panel 1) toward the rear of the vehicle; an upper reinforcement 20B that constitutes the upper portion of the connecting member 20 and extends from the tip patch 20A to the lateral strength member 10 and reinforcing member 12; and a lower reinforcement 20C that constitutes the lower portion of the connecting member 20. The following description will focus primarily on the elements divided in terms of deformation.

The rigidity retaining portion 21 extends from the transverse strength member 10 toward the front of the vehicle and is located above the steering column support hanger 30. The rigidity retaining portion 21 is formed to have sufficient rigidity to withstand collision loads that may be input from the front of the vehicle, and forms the rear end of the connecting member 20 that is welded to the transverse strength member 10 and the reinforcing member 12.

The rigidity retaining portion 21 has, for example, a flat plate portion 21a and flange portions 21b extending downward from both ends of the plate portion 21a in the vehicle width direction. The plate portion 21a is formed to be wider in the vehicle width direction as it moves toward the rear of the vehicle, and the flange portion 21b is formed to be wider in the vehicle vertical direction as it moves toward the rear of the vehicle. The plate portion 21a extends from the upper surface of the reinforcing member 12 toward the front of the vehicle, sloping upward.

The overall deformation portion 22 has a front connection portion 221 connected to the vehicle body panel 1, a first rear connection portion 22a connected to the steering column support hanger 30, and a second rear connection portion 22b connected to the rigidity retention portion 21. The overall deformation portion 22 forms a structure that runs around the vehicle via the front connection portion 221, the first rear connection portion 22a, and the second rear connection portion 22b and is open in the vehicle width direction. The overall deformation portion 22 constitutes the majority of the connecting member 20 between the vehicle body panel 1, the rigidity retention portion 21, and the steering column support hanger 30. The rigidity retention portion 21 and the steering column support hanger 30, which are capable of withstanding impact loads, are located behind the overall deformation portion 22, and the rear end of the overall deformation portion 20 is supported by the rigidity retention portion 21 and the steering column support hanger 30.

The front deformation section 23 has a main vertical member 231 that extends in the vertical direction of the vehicle inside the overall deformation section 22, and the main vertical member 231 and the portion of the overall deformation section 22 that is further forward of the main vertical member 231 form a structure that is open in the vehicle width direction. In other words, the front deformation section 23 forms the front portion of the connecting member 20, including the front connection section 221, and is composed of a front portion of the overall deformation section 22 and the main vertical member 231.

In this way, in the steering support structure 100, the front connection portion 221, rigidity retaining portion 21, and steering column support hanger 30 are formed with relatively high rigidity as deformation suppression portions (non-deformation portions). Between the rigidity retaining portion 21 and steering column support hanger 30 and the front connection portion 221, there is disposed a deformation portion (an overall deformation portion 22 including the front deformation portion 23) that has sufficient rigidity under normal conditions but is prone to deformation when an impact load is input.

Here, the portion of the overall deformation portion 22 above the vehicle (222) that constitutes part of the front deformation portion 23 extends linearly in the longitudinal direction of the vehicle, while the portion of the overall deformation portion 22 below the vehicle (223) extends in a convexly curved shape below the vehicle at the first rear connection portion 22a. Hereinafter, the portion of the overall deformation portion 22 above the vehicle will be referred to as the upper reinforcement body 222, and the portion of the overall deformation portion 22 below the vehicle will be referred to as the lower reinforcement body 223.

In the overall deformation section 22, the front connection section 221 is formed, for example, in a box shape that opens toward the rear of the vehicle, and constitutes the tip patch 20A into which the impact load is input. The front connection section 221 has a flat contact surface 221a that contacts the vehicle body panel 1. The contact surface 221a extends in the vertical and lateral directions of the vehicle, so that when a collision load is input from the front of the vehicle toward the rear of the vehicle, the collision load is input approximately perpendicular to the contact surface 221a of the front connection section 221. A threaded portion is formed in the contact surface 221a of the front connection section 221 into which a fastener 15 consisting of a bolt is threaded, and a hole is opened in the vehicle body panel 1 through which the fastener 15 is inserted. With the fastener 15 threaded into the front connection portion 221, the vehicle body panel 1 is clamped between the head of the fastener 15 and the abutment surface 221a of the front connection portion 221, and the front connection portion 221 is fastened and fixed (connected) to the vehicle body panel 1 by the fastener 15.

The upper reinforcement body 222 extends from the front connection portion 221 to the front end of the rigidity retention portion 21, and together with the rigidity retention portion 21, constitutes the upper reinforcement 20B. The portion of the upper reinforcement body 222 that constitutes part of the front deformation portion 23 extends linearly in the longitudinal direction of the vehicle. The second rear connection portion 22b that connects to the rigidity retention portion 21 in the overall deformation portion 22 is the rear end portion of the upper reinforcement body 222.

The upper reinforcement body 222 is formed integrally with the rigidity retention portion 21 by press molding, and extends continuously from the rigidity retention portion 21 in the longitudinal direction of the vehicle. The front end of the upper reinforcement body 222 is welded to the inner surface of the upper wall of the front connection portion 221 while incorporated within the front connection portion 221. The upper reinforcement body 222 has, for example, a flat upper plate portion 222a and upper flange portions 222b extending downward from both ends of the upper plate portion 222a in the vehicle width direction. The upper plate portion 222a is formed with a predetermined width that is smaller in the vehicle width direction than the plate portion 21a of the rigidity retention portion 21 and extends continuously from the plate portion 21a, and the upper flange portion 222b extends continuously from the flange portion 21b of the rigidity retention portion 21.

The lower reinforcement body 223 is located below the upper reinforcement body 222 and extends from the front connection portion 221 via the first rear connection portion 22a to the second rear connection portion 22b, constituting part of the lower reinforcement 20C. The lower reinforcement body 223 extends in a shape that is bent convexly downward of the vehicle at the first rear connection portion 22a. In other words, the first rear connection portion 22a, which connects to the steering column support hanger 30 in the overall deformation portion 22, is a corner of the lower reinforcement body 223 that is bent convexly downward of the vehicle.

The front end of the lower reinforcement body 223 is welded to the inner surface of the lower wall of the front connection portion 221 while it is installed within the front connection portion 221. The rear end of the lower reinforcement body 223 is welded to the rear end portion (second rear connection portion 22b) of the upper reinforcement body 222. The lower reinforcement body 223 has, for example, a flat lower plate portion 223a and lower flange portions 223b extending upward from both ends of the lower plate portion 223a in the vehicle width direction. The portion of the lower flange portion 223b closer to the second rear connection portion 22b than the first rear connection portion 22a is formed to become wider in the vehicle up-down direction as it approaches the second rear connection portion 22b.

In the front deformation portion 23, the main vertical member 231 extends upward from a predetermined position between the front connection portion 221 and the first rear connection portion 22a in the overall deformation portion 22. Specifically, the main vertical member 231 is formed integrally with the lower reinforcement body 223. The main vertical members 231 extend upward from predetermined positions on the front side of the first rear connection portion 22a of each lower flange portion 223b on both sides of the lower reinforcement body 223 in the vehicle width direction, and are welded to the upper flange portion 222b of the upper reinforcement body 222.

The front deformation portion 23 has a weakened portion 232 in an extension portion 222c that extends linearly in the vehicle fore-and-aft direction between the front connection portion 221 and the upper end of the main vertical member 231. The extension portion 222c is the front portion of the upper reinforcement body 222 (in other words, the front portion of the upper portion of the overall deformation portion 22 above the vehicle).

In this embodiment, the weakened portion 232 is formed in an arc shape by curving the middle portion of the extension portion 222c in an arc shape that is concave downward toward the vehicle. In other words, the weakened portion 232 is formed by smoothly curving the upper plate portion 222a downward into an arc shape at a predetermined position in the vehicle fore-and-aft direction of the extension portion 222c when viewed in the vehicle width direction.

In this embodiment, the connecting member 20 has at least one sub-vertical member 233 extending in the vehicle vertical direction inside the overall deformation portion 22 and rearward of the main vertical member 231. Here, one sub-vertical member 233 is provided on each side in the vehicle width direction. Each sub-vertical member 233 is formed integrally with the lower reinforcement body 223. Each sub-vertical member 233 extends upward from a predetermined position on the lower flange portion 223b between the lower end of the main vertical member 231 and the first rear connection portion 22a, and is welded to the upper flange portion 222b. The upper end of the sub-vertical member 233 is connected to the upper end of the main vertical member 231. In this way, the main vertical member 231 and the sub-vertical member 233 are arranged to extend inside the overall deformation portion 22 when viewed in the vehicle width direction, thereby forming, in order from the front of the vehicle when viewed in the vehicle width direction, a first opening V1, a second opening V2, and a third opening V3. In the connecting member 20 configured as described above, the lower reinforcement 20C is made up of the lower reinforcement body 223, the main vertical member 231, and the secondary vertical member 233. Furthermore, a through-hole 223c is opened in the lower plate portion 223a, at least below the first opening V1 (see Figure 4).

The opening area of the opening (first opening V1) formed by providing the main vertical member 231 in the front deformation section 23 is set larger than the opening area of each of the openings (second opening V2 and third opening V3) formed further rearward of the vehicle than the opening (first opening V1) in the front deformation section 23 by providing the secondary vertical member 233 in the overall deformation section 22.

In this embodiment, the first angle θ1, which is the angle between the main vertical member 231 and the extension portion 222c, is set to an acute angle. Specifically, the first angle θ1 is the angle between the main vertical member 231 and the upper plate portion 222a of the extension portion 222c when viewed from the vehicle width direction. The connection point (joint point) P between the main vertical member 231 and the extension portion 222c is set near the rear end of the weak portion 232. The connection point P has a width in the fore-and-aft direction of the vehicle.

In this embodiment, the lower reinforcement body 223, which is the portion of the overall deformation portion 22 located below the vehicle, is bent at an obtuse angle at the first rear connection portion 22a. Specifically, the lower plate portion 223a of the lower reinforcement body 223 is bent at an obtuse angle at the first rear connection portion 22a when viewed from the vehicle width direction, and the second angle θ2, which is the angle between the portion of the lower plate portion 223a that is further forward of the vehicle than the first rear connection portion 22a and the portion of the lower plate portion 223a that is further rearward of the vehicle than the first rear connection portion 22a, is set to an obtuse angle.

In this embodiment, the upper reinforcement body 222, which is the portion of the overall deformation portion 22 above the vehicle, extends linearly in the fore-and-aft direction of the vehicle from the front connection portion 221 to a midpoint M corresponding to directly above the first rear connection portion 22a, and is inclined downward from the midpoint M to the rigidity retention portion 21 toward the rear of the vehicle. In other words, the portion of the upper reinforcement body 222 rear of the extension portion 222c extends linearly toward the rear of the vehicle to the midpoint M. This midpoint M is located further rearward of the vehicle than the secondary vertical member 233. The portion of the upper plate portion 222a of the upper reinforcement body 222 rearward of the midpoint M is inclined in the same inclination direction as the plate portion 21a of the rigidity retention portion 21.

Here, in order to retain the steering column and protect occupants in the vehicle cabin, it would be ideal if all of the energy of an impact load that may be input from the front of the vehicle were absorbed by deformation of parts further forward of the steering support structure 100. However, there are cases where the deformation of parts further forward of the vehicle is not able to absorb all of the energy of the impact load, and the vehicle body panel 1 (dash panel, etc.) is pushed toward the rear of the vehicle. In this case, as explained below, the steering support structure 100 suppresses the impact transmitted to the steering column and lateral strength member 10 by deforming the deforming portion (i.e., the overall deforming portion 22 including the front deforming portion 23).

Next, the deformation process of the connecting member 20 and the process of absorbing the energy of the impact load when a collision load is input to the connecting member 20 of the steering support structure 100 according to this embodiment from the front of the vehicle will be described with reference to Figures 1, 5, 6, etc. Figure 5 is a conceptual diagram for explaining the deformation process of the connecting member 20, and Figure 6 is a conceptual diagram for explaining the process of absorbing the energy of the impact load input to the connecting member 20.

In Figure 5, the outline D1 of the connecting member 20 in its normal state before the input of the impact load is shown in a solid line, the outline D2 of the deformed connecting member 20 in the initial stage after the input of the impact load is shown in a dashed line, and the outline D3 of the connecting member 20 that has further deformed after the initial stage is shown in a dashed line. Also in Figure 6, the horizontal axis represents the elapsed time t from the time the impact load is input, and the vertical axis represents the amount of energy E absorbed (decreased amount) thereafter, with E0 being the input energy at the time the impact load is input (t=0). In other words, the lower the position on the vertical axis, the greater the amount of impact energy absorbed. Also in Figure 6, curve C, which represents the energy absorption characteristics of the connecting member 20, is shown in a solid line, and curve C', which represents an example of the energy absorption characteristics of a conventional connecting member, is shown in a dashed line.

In the steering support structure 100, the overall deformation portion 22 and the front deformation portion 23 are both structures that open in the vehicle width direction. Therefore, (1) under normal circumstances, both the overall deformation portion 22 and the front deformation portion 23 maintain sufficient rigidity, while (2) when an impact load is input to the front connection portion 221 of the connecting member 20, both the overall deformation portion 22 and the front deformation portion 23 allow deformation in the input direction of the impact load. Furthermore, the portion of the overall deformation portion 22 above the vehicle that constitutes part of the front deformation portion 23 extends linearly in the fore-and-aft direction of the vehicle, but the portion of the overall deformation portion 22 below the vehicle (upper reinforcement main body 222) extends in a bent shape at the first rear connection portion 22a. Therefore, the portion of the overall deformation portion 22 (lower reinforcement main body 223) between the front connection portion 221 and the first rear connection portion 22a slopes downward toward the rear of the vehicle.

Therefore, when an impact load is applied to the front connection portion 221, as shown by dashed line D1 in Figure 5, bending deformation is induced in the overall deformation portion 22, primarily originating from the first rear connection portion 22a, while the overall deformation portion 22 is firmly supported from the rear of the vehicle by the steering column support hanger 30 and the rigidity retaining portion 21. As a result, the overall deformation portion 22 is structured to deform overall when an impact load is applied, causing the front connection portion 221 to move upward and rearward. On the other hand, in the front deformation portion 23, the weak portion 232 is provided in the extension portion 222c that extends linearly in the fore-and-aft direction of the vehicle, where the impact load is easily transmitted. Therefore, deformation primarily originating from the weak portion 232 is more actively induced than bending deformation in the first rear connection portion 22a.

Here, the impact load input to the front connection portion 221 is transmitted to the weak portion 232 and the first rear connection portion 22a. As a result, in the early stages after the impact load is input (the range of t = 0 to t1 in Figure 6), as shown by contour D2 in Figure 5, deformation of the front deformation portion 23 originating from the weak portion 232 (hereinafter referred to as "front deformation") and overall deformation of the overall deformation portion 22 originating from the first rear connection portion 22a (hereinafter referred to as "overall deformation") occur simultaneously, and in the front deformation portion 23, the front deformation and overall deformation occur in an overlapping manner.

However, due to the mechanical characteristics of the structure, whereby force flows all at once into weak points where deformation has progressed (i.e., concentrated load occurs), once the front deformation has progressed to a certain extent, the force that was inducing the overall deformation also flows into the weak part 232, and most of the impact load input to the front connection part 221 flows all at once into the weak part 232. As a result, from this point onwards (the range t = t1 to t2 in Figure 6), as shown by contour D3 in Figure 5, the overall deformation is suppressed and hardly occurs at all, and the front deformation becomes dominant.

The connecting member 20 deforms through the above-described deformation process. In other words, in the initial stage (t = 0 to t1) after the impact load is applied, a portion of the energy E0 of the applied impact load is consumed (converted) into energy for both forward deformation and overall deformation, as shown by contour D2 in Figure 5, and is rapidly absorbed as shown in Figure 6. Thereafter (t > t1), once the forward deformation has progressed to a certain extent, most of the remaining energy of the impact load is consumed (converted) into energy for forward deformation, as shown by contour D3 in Figure 5, and is slowly absorbed as shown in Figure 6. In this way, the deformation of the forward deformation portion 23 (forward deformation) continues longer than the deformation of the overall deformation portion 22 (overall deformation) (t = 0 to t2). Due to the difference in duration between the forward deformation and overall deformation, the energy E0 of the applied impact load is gradually (stepwise) absorbed over time. In other words, in Figure 6, in the initial stage (t = 0 to t1), curve C, which indicates the energy absorption characteristics, shows a steep downward slope as time t passes, indicating that the connecting member 20 is rapidly absorbing energy E. After that (t > t1), curve C transitions to a gentler slope as time t passes, and energy E becomes zero at time t2, indicating that the connecting member 20 is slowly absorbing (gradually reducing) energy E over time. In other words, compared to the conventional curve C', curve C transitions more slowly from the time the impact load is input (t = 0) to the landing point (t = t2) where energy E becomes zero, thereby reducing the load on the occupant with the steering support structure 100.

In this way, the steering support structure 100 can gradually absorb the energy of impact loads input from the front of the vehicle.

In this embodiment, the weak portion 232 is formed in an arc shape by curving the middle portion of the extension portion 222c into an arc shape concave downward toward the vehicle. This effectively induces forward deformation in the front deformation portion 23 starting from the weak portion 232, thereby effectively inducing gradual deformation. Furthermore, by forming the weak portion 232 in an arc shape, significant stress concentration that can occur in conventional notched weak portions can be avoided. This effectively prevents cracks from occurring in the weak portion 232 due to strong vibration forces that can occur when traveling on rough roads or other road surfaces. Furthermore, if the weak portion were formed using a V-shaped horizontal bead extending in the vehicle width direction, for example, cracks could occur during molding of the flange portion of the upper reinforcement 20B, making molding difficult. In contrast, the arc-shaped weak portion 232 can be molded without concern for cracks. Additionally, by adjusting the arc diameter of the arc-shaped fragile portion 232, it is easier to control the amount of deformation and formability of the front deformation compared to, for example, a fragile portion made of a V-shaped horizontal bead. Furthermore, by adjusting the arc diameter of the fragile portion 232, it is also possible to control the duration of the front deformation alone (deformation in the range t > t1 in Figure 6).

In this embodiment, the opening area of the opening (first opening V1) of the front deformation portion 23 is set larger than the opening area of each of the openings (second opening V2 and third opening V3) located rearward of the vehicle than the first opening V1 in the overall deformation portion 22. This reduces the rigidity of the front deformation portion 23 compared to the rigidity of the portion of the overall deformation portion 22 rearward of the front deformation portion 23, effectively inducing forward deformation in the front deformation portion 23.

In this embodiment, the first angle θ1, which is the angle between the main vertical member 231 and the extension portion 222c, is set to an acute angle, and the connection point (joint point) P between the main vertical member 231 and the extension portion 222c is set near the rear end of the weak portion 232. This effectively suppresses the occurrence of cracks, makes it easier for impact loads to act on the weak portion 232, and promotes further forward deformation in the front deformation portion 232.

If the lower reinforcement body 223 of the overall deformation portion 22 were bent at an acute angle at the first rear connection portion 22a, when an impact load was applied from the front of the vehicle, the overall deformation portion 22 would immediately transition to overall deformation due to bending deformation with the first rear connection portion 22a as the starting point (axis of rotation), resulting in a reduced absorption of the energy of the impact load. In contrast, in this embodiment, the lower reinforcement body 223 of the overall deformation portion 22 is bent at an obtuse angle at the first rear connection portion 22a. As a result, when an impact load is applied from the front of the vehicle, the lower reinforcement body 223 is stretched to a certain extent in the fore-and-aft direction to absorb the impact load, and then gradually transitions to overall deformation due to bending deformation, thereby increasing the absorption of the energy of the impact load. Furthermore, providing the lower reinforcement 20C with the first rear connection portion 22a at an obtuse angle facilitates the molding of the main vertical member 231, the secondary vertical member 233, and the lower flange portion 223b.

In this embodiment, the upper reinforcement body 222, which is the upper portion of the overall deformation portion 22, extends linearly in the fore-and-aft direction of the vehicle from the front connection portion 221 to a midpoint M directly above the first rear connection portion 22a, and slopes downward from the midpoint M to the rigidity retention portion 21 toward the rear of the vehicle. As a result, when an impact load is applied from the front of the vehicle, the front portion of the upper reinforcement body 222 that extends linearly in the fore-and-aft direction of the vehicle braces itself to some extent in the fore-and-aft direction to absorb the impact load, while the sloped portion behind the midpoint M effectively induces overall deformation. As a result, overall deformation can be prevented from completely stopping even after the initial stage following application of the impact load (t>t1), for example, resulting in increased absorption of impact energy.

In addition, a through-hole 223c is opened in the lower plate portion 223a of the lower reinforcement body 223 below the first opening V1 (see Figure 4), which effectively induces overall deformation and front deformation.

The above describes an embodiment of the present invention, but the present invention is not limited to the above embodiment, and modifications and variations are possible based on the technical concept of the present invention.

For example, while only one sub-vertical member 233 is provided on each side in the vehicle width direction, this is not limited to this, and two or more may be provided on each side in the vehicle width direction. Furthermore, while the connecting member 20 is formed by welding together three molded parts: the tip patch 20A, the upper reinforcement 20B, and the lower reinforcement 20C, the number of molded parts to be welded together is not limited to this, and the connecting member may be divided into any number of parts.

1...body panel, 10...transverse strength member, 20...connecting member, 21...rigidity retention portion, 22...overall deformation portion, 22a...first rear connection portion, 22b...second rear connection portion, 221...front connection portion, 222c...extension portion, 23...front deformation portion, 231...main vertical member, 232...weak portion, 233...sub-vertical member, 30...steering column support hanger, 100...steering support structure, M...midpoint, P...connection point, V1...first opening (opening), V2...second opening (opening), V3...third opening (opening)

Claims (5)

A steering support structure comprising: a lateral strength member extending in a vehicle width direction behind a body panel on a front side of the vehicle; a connecting member connecting the lateral strength member to the body panel; and a steering column support hanger extending from the lateral strength member to the front of the vehicle below the connecting member,
The connecting member is
a rigidity retaining portion extending from the transverse strength member toward the front of the vehicle and positioned above the steering column support hanger;
an overall deformation portion having a front connection portion connected to the vehicle body panel, a first rear connection portion connected to the steering column support hanger, and a second rear connection portion connected to the rigidity retaining portion, the overall deformation portion forming a structure that runs around the front connection portion, the first rear connection portion, and the second rear connection portion and is open in the vehicle width direction;
a front deformation section having a main vertical member extending in the vehicle up-down direction inside the overall deformation section, the main vertical member and a portion of the overall deformation section forward of the main vertical member forming a structure that is open in the vehicle width direction;
Including,
a portion of the overall deformation portion located below the vehicle extends in a bent shape at the first rear connection portion,
a portion of the entire deformation portion above the vehicle that constitutes at least a part of the front deformation portion extends linearly in the front-rear direction of the vehicle,
the main longitudinal member extends upward from a predetermined position between the front connection portion and the first rear connection portion in the overall deformation portion,
the front deformation portion has a weakened portion in an extension portion that extends linearly in the vehicle front-rear direction between the front connection portion and an upper end of the main longitudinal member,
A steering support structure characterized in that the portion of the overall deformation portion above the vehicle extends linearly in the fore-and-aft direction of the vehicle from the front connection portion to an intermediate point corresponding to directly above the first rear connection portion, and slopes downwardly toward the rear of the vehicle from the intermediate point to the rigidity retaining portion . The steering support structure of claim 1, wherein the weakened portion is formed in an arc shape by curving a middle portion of the extension portion into an arc shape concave downward toward the vehicle. the connecting member has at least one sub-vertical member extending in the vehicle up-down direction on the inside of the overall deformation portion and rearward of the main vertical member,
A steering support structure as described in claim 1 or 2, wherein the opening area of the opening formed by providing the main vertical member in the front deformation portion is set larger than the opening area of each of the openings formed rearward of the opening in the front deformation portion by providing at least one secondary vertical member in the overall deformation portion. The angle between the main vertical member and the extension portion is set to an acute angle,
4. The steering support structure according to claim 1, wherein a connection point between the main longitudinal member and the extension portion is set near a rear end of the weakened portion. A steering support structure according to any one of claims 1 to 4, wherein the portion of the overall deformation section below the vehicle is bent at an obtuse angle at the first rear connection section.