Vehicle pillar
The vehicle pillar design with inclined support walls addresses molding complexity and weight issues by enhancing structural strength and reducing weight through optimized cross-sectional reinforcement.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- TOYODA IRON WORKS CO LTD
- Filing Date
- 2024-10-23
- Publication Date
- 2026-05-11
AI Technical Summary
Existing vehicle pillars face challenges in achieving dimensional accuracy during molding due to complex curved surfaces, require enhanced strength against collision loads, and often result in excessive weight.
A vehicle pillar design featuring a main member with a closed cross-section and a reinforcing member that includes inclined support walls, welded to the main member, which supports the outer wall to improve strength and reduce weight by optimizing the cross-sectional shape.
The design enhances buckling resistance and delays buckling onset, allowing for weight reduction while maintaining or improving structural integrity under collision loads.
Smart Images
Figure 2026075815000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a vehicle pillar.
Background Art
[0002] A vehicle pillar is generally a body structural member having a closed cross-section and is usually composed of an outer member and an inner member. Between the outer member and the inner member, a reinforcing member also called a hinge reinforcement is provided in a partial range in the longitudinal direction (particularly a range including the height of the door hinge). Such a reinforcing member is designed not only to reinforce the door hinge fixing portion but also to prevent the pillar from greatly bending inward at the central portion when receiving a side collision and threatening the survival space of the occupant. For example, such a vehicle pillar is described in Japanese Patent Application Laid-Open No. 2021-095048.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] The hinge reinforcement often has a U-shaped cross-section, but its specific shape is not limited to a simple rectangular shape or trapezoidal shape. For example, the hinge reinforcement described in the above publication has a trapezoidal cross-section in which both leg portions are not straight but curved inward, suppressing the outward swelling of the wall portions corresponding to both leg portions during a side collision. However, it is difficult to obtain dimensional accuracy during molding for a structure having such a large curved surface portion. Therefore, it is desired to have a shape that is easy to mold, enhance the strength against the load applied during a collision, and in some cases, enable weight reduction of the pillar.
Means for Solving the Problems
[0005] One embodiment is a vehicle pillar comprising a main member having a closed cross-section and a reinforcing member disposed inside the main member, wherein the reinforcing member has an outer wall disposed on the outside side of the vehicle, a front wall disposed on the front side, a rear wall disposed on the rear side, and inclined support walls that planarly connect the outer wall and the front wall, and the outer wall and the rear wall, in at least a portion of the longitudinal direction of the reinforcing member, and the reinforcing member is welded to the main member by the outer wall, the front wall and the rear wall.
[0006] By providing inclined support walls to the reinforcing members in this way, they particularly function to support the outer portion of the main member. This improves the strength against inward buckling of the outer portion of the main member when a longitudinal compressive load is applied to that portion. Furthermore, by reducing the plate thickness of the constituent members due to the improved strength, it is possible to lighten the pillar.
[0007] In some embodiments, the outer wall of the reinforcing member has a recessed bead extending in the longitudinal direction of the vehicle pillar.
[0008] As a result, the recess in the outer wall is constrained at both edges of the concave bead, allowing for a larger effective width based on Kármán's theory, which will be discussed later.
[0009] In some embodiments, the front wall and the rear wall each have a plurality of welding protrusions along the longitudinal direction for welding to the main member, and each of the welding protrusions has a planar welding surface.
[0010] This allows for the functional separation of the front wall, which provides the welding seating surface, and the inclined support wall that supports the rear wall and outer wall, thereby simplifying the design of each component.
[0011] In some embodiments, the inclined support wall is in contact with at least one of the multiple welding protrusions of the front wall and the rear wall.
[0012] As a result, even if the width of the outer wall is reduced, the inclined support wall can still maximize the effect of supporting the outer wall.
[0013] In some embodiments, the outer angle formed by the inclined support wall with respect to the outer wall is larger than the outer angles formed by the front wall and the rear wall.
[0014] As a result, the function of the inclined support wall to support the outer wall can be effectively exerted.
[0015] In some embodiments, the outer angle formed by the inclined support wall with respect to the outer wall is 40 degrees or more.
[0016] As a result, the function of the inclined support wall to support the outer wall can be reliably exerted.
Brief Description of the Drawings
[0017] [Figure 1] It is a perspective view of the B-pillar of a vehicle as one embodiment. [Figure 2] It is a perspective view of a reinforcing member having an inclined support wall. [Figure 3] It is a cross-sectional view of the B-pillar. [Figure 4] It is a cross-sectional view when the cross-section of the B-pillar in FIG. 3 is deformed under a bending moment. [Figure 5] It is a diagram showing the relationship between the load and displacement (stroke) of the B-pillar having the cross-section in FIG. 3. [Figure 6] It is a cross-sectional view of the B-pillar as a comparative example. [[ID=4L]] [Figure 7] It is a cross-sectional view when the cross-section of the B-pillar in FIG. 6 is deformed under a bending moment. [Figure 8] It is a diagram showing the relationship between the load and displacement of the B-pillar corresponding to the outer angles of each size in Table 1. [Figure 9] It is a cross-sectional view of the B-pillar provided with an inclined support wall on the outer member as another embodiment. [[ID=SO]]
Modes for Carrying Out the Invention
[0018] Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0019] [B pillar] FIG. 1 shows a B pillar 10 of a vehicle as one embodiment. The B pillar 10 (also called a center pillar) is a structural member that constitutes the side portion of the vehicle body, and extends along the vertical direction so as to connect the roof side rail 12 and the side sill 14. A rear door is attached to the B pillar 10 via a door hinge. The B pillar 10 exhibits strength particularly when the vehicle is subjected to a side collision. The B pillar 10 generally has a convex curved shape facing outward. The B pillar 10 is provided with an inclination such that the upper end is behind the lower end. Hereinafter, the features of the B pillar 10 will be described. As another embodiment, the features described below can also be applied to an A pillar (front pillar) or a C pillar (rear pillar). <C
[0020] As shown in FIG. 3, the B pillar 10 includes a main member 20 having a closed cross section. The main member 20 can be composed of an outer member 30 and an inner member 40 that are elongated in the vertical direction. Both the outer member 30 and the inner member 40 can be formed by press molding of a steel plate. The outer member 30 generally has a hat-shaped cross section, and has an outer wall 31 located on the outer side of the vehicle, a front wall 32 located on the front side, a rear wall 33 located on the rear side, and flanges 34, 35 that extend in a direction away from each other from the ends of the front wall 32 and the rear wall 33. A concave bead 36 extending in the longitudinal direction of the B pillar 10 can be provided on the outer wall 31 of the outer member 30. The depth of the concave bead 36 is not limited. As another embodiment not shown, the concave bead on the outer wall 31 may not be provided. The inner member 40 closes the open side of the outer member 30 having a hat-shaped cross section. The inner member 40 has flanges 42, 44 on both edges of the front side and the rear side. The flanges 42, 44 of the inner member 40 are respectively overlapped with the flanges 34, 35 of the outer member 30 and joined by, for example, spot welding.
[0021] [Reinforcement member] As shown in Figures 2 and 3, the B-pillar 10 includes a reinforcing member 50 inside the main member 20. The outer wall 31 of the outer member 30 is provided with a door hinge fixing portion 37 (see Figure 1) to which a door hinge for the rear door is fixed, and the reinforcing member 50 can also serve to reinforce this door hinge fixing portion 37. Such a reinforcing member 50 is also called a hinge reinforcement. The reinforcing member 50 can be formed by cold, warm, or hot pressing, and high-tensile steel plates or ultra-high-tensile steel plates can be used. The thickness of the reinforcing member 50 is not limited and can be set to a size according to requirements.
[0022] The reinforcing member 50 has an outer wall 51 located on the outside of the vehicle, a front wall 52 located on the front side, and a rear wall 53 located on the rear side. The reinforcing member 50 is joined to the outer member 30 by the outer wall 51, the front wall 52, and the rear wall 53, for example, by spot welding. The outer wall 51 and the front wall 52 of the reinforcing member 50 can be provided with welding protrusions 54 that project toward the outer member 30 and have a planar welding seat surface (see Figure 2). Although not shown, the rear wall 53 can also be provided with similar welding protrusions. Multiple welding protrusions 54 are provided on each wall along the longitudinal direction of the B pillar 10. Note that in cross-sectional views such as Figure 3, the positions of the spot welds are indicated by "x" marks, but the position in the longitudinal direction is ignored. In other words, the actual spot welds (and therefore the welding protrusions 54) are dispersed in the longitudinal direction and are not necessarily located within the cross-section shown in each figure.
[0023] A recessed bead 56 extending in the longitudinal direction of the B pillar 10 can be provided on the outer wall 51 of the reinforcing member 50. The recessed bead 56 can be provided at a position corresponding to the recessed bead 36 of the outer member 30 that constitutes the main member 20. The depth of the recessed bead 56 is not limited. In another embodiment not shown, the recessed bead on the outer wall 51 may be omitted.
[0024] [Slope support wall] As shown in Figures 2 and 3, the front wall 52 and outer wall 51 of the reinforcing member 50, and the rear wall 53 and outer wall 51 are connected by planar inclined support walls 57 and 58, respectively. During a side collision of a vehicle, a bending moment is applied to the B-pillar 10, and a large compressive stress is generated in the outer wall 31 of the outer member 30, which is located on the outermost side of the B-pillar 10. When the outer wall 31 can no longer withstand this compressive stress, the central part buckles, concaves inward towards the vehicle, while the front wall 32 and rear wall 33 bulge outward towards the B-pillar 10, causing the closed cross-section to collapse. The inclined support walls 57 and 58 of the reinforcing member 50 play a role in suppressing the buckling of the outer wall 31 of the outer member 30 by supporting the outer wall 31 of the outer member 30 and the outer wall 51 of the reinforcing member 50 itself. In other words, the inclined support walls 57 and 58 improve the buckling strength of the outer wall 31. The external angle α that the inclined support walls 57 and 58 make with respect to the outer wall 51 (i.e., the internal angle that the inclined support walls 57 and 58 make with respect to the extended plane of the outer wall 51) can be made larger than the external angle β that they make with respect to the corresponding front wall 52 and rear wall 53 (i.e., the internal angle that they make with respect to the extended plane of the front wall 52 and rear wall 53). Alternatively, the external angle α made by the inclined support walls 57 and 58 can be, for example, 40 degrees or more, 45 degrees or more, 50 degrees or more, 55 degrees or more, 60 degrees or more, or 65 degrees or more. This allows the inclined support walls 57 and 58 to effectively perform their function of supporting the outer walls 31 and 51.
[0025] The inclined support walls 57 and 58 extend along the longitudinal direction of the reinforcing member 50, but do not need to extend along the entire length of the reinforcing member 50. In one embodiment, the inclined support walls 57 and 58 can be provided in a range that includes the height of the vehicle's beltline 16 (see Figures 1 and 2). Since the bending moment acting on the B-pillar 10 during a side collision is approximately maximum at the height of the beltline 16, providing the inclined support walls 57 and 58 in such a range makes the support function more effective.
[0026] As shown in Figure 6, the conventional B-pillar 210's reinforcing member 250 had its outer wall 251 widest possible in order to maximize the sectional strength by placing as much material as possible on the outward side. As a result, the front wall 252 and rear wall 253 were directly connected to the outer wall 251 to form a ridge, and the overall cross-section was a square cross-section along the outer member 30 which had a hat-shaped cross-section. Figure 7 shows the results of a computer simulation of the deformation behavior of the cross-section in Figure 6. From the results, it can be seen that when a large compressive stress occurs in the outer wall 31 of the outer member 30, the outer wall 251 of the reinforcing member 250 welded to the outer member 30 buckles by collapsing inward together with the outer wall 31 of the outer member 30. On the other hand, Figure 4 shows the results of a simulation of the deformation behavior of the cross-section in Figure 3. Note that Figure 4 shows the deformed cross-section when the impacting body has displaced (stroked) by the same amount as the buckled cross-section in Figure 7. As shown in Figure 3, by providing inclined support walls 57 and 58 on the reinforcing member 50, the inclined support walls 57 and 58 support the outer wall 31 of the outer member 30 against compressive stress due to bending moment, as shown in Figure 4, thereby suppressing the central indentation of the outer wall 31 and allowing it to withstand higher stress. Comparing Figure 4 with Figure 7, it can be seen that the outer walls 31 and 51 of the B pillar 10 with inclined support walls 57 and 58 have not buckled even after the outer walls 31 and 251 of the B pillar of the base structure without inclined support walls have buckled. From the relationship between load and displacement (stroke) shown in Figure 5, it can be seen that the B pillar 10 with inclined support walls 57 and 58 can support a larger load than the B pillar of the base structure. As a result, the timing of buckling can be delayed, and the buckling strength of the B pillar 10 can be improved. It is also possible to reduce the weight by reducing the plate thickness of the outer member 30 and reinforcing member 50 by the amount by which the buckling strength has been improved.
[0027] [Consider the effective width] Regarding the buckling strength when a compressive load is applied from an unrestrained edge to a plate material with both opposing edges restrained, Kármán's effective width theory is known. This theory states that the actual strength against such a compressive load is not the entire width between the two restrained edges, but only the region near the restrained edges (effective width). Applying this to the outer wall 51 that receives the compressive load in the reinforcing member 50 of the B pillar 10, the outer wall 51 is considered to be restrained at the ridge connecting the front wall 52 and the rear wall 53, so the effective width exists near that ridge, as indicated by the arrows in Figure 3. If a recessed bead 56 with a certain depth or more exists in the center of the outer wall 51, the outer wall 51 is also considered to be restrained by the step difference at both edges of the recessed bead 56, so the effective width also occurs on both sides of the recessed bead 56. In Figure 3, the effective width near the front wall 52 and the rear wall 53 and the effective width near the recessed bead 56 are combined and depicted.
[0028] According to Karman's theory, the effective width does not depend on the total width between the two edges, but is proportional to the square root of the plate thickness and Young's modulus, and inversely proportional to the square root of the yield stress. Verification revealed that for materials commonly used in vehicle pillars, the width between the restraining parts of the conventional outer wall 251 (from the end of the outer wall 251 to the end of the recessed bead 56) is larger than the effective width obtained based on Karman's theory (arrow in Figure 6), indicating that there is wasted cross-sectional space for the longitudinal compressive stress generated by the bending moment. In recent years, B-pillars 10 tend to have larger cross-sections to obtain high collision safety, and the materials used tend to be high-strength materials such as ultra-high-tensile steel, but the effective width based on theory becomes shorter as the material strength (yield stress) increases. Furthermore, if the recessed bead 56 is shallow, the steps at both edges of the recessed bead 56 cannot restrain the outer wall 251. Therefore, as shown in Figure 6, the effective width is thought to occur only near the ridge formed by the front wall 252 and the rear wall 253 of the outer wall 251, and not immediately on either side of the recessed bead 56.
[0029] In one embodiment, the width of the portion of the outer wall 51 of the reinforcing member 50 that protrudes outward from the front and rear of the vehicle is limited to the effective width obtained from Karman's theoretical formula. This not only allows for the provision of inclined support walls 57 and 58 by reducing the width of the outer wall 51, but also allows the outer wall 51 itself to generate sufficient stress, thereby effectively utilizing its cross-sectional shape.
[0030] [Positional relationship with welding protrusions] The reinforcing member 50 is not welded to the outer member 30 in the inclined support walls 57 and 58. However, as shown in Figure 2, the inclined support walls 57 and 58 are in contact with the welding protrusions 54 provided on the corresponding front wall 52 and rear wall 53, respectively. This allows for a larger angle of the inclined support walls 57 and 58 even when the width of the outer wall 51 is reduced, maximizing the effect of supporting the outer walls 31 and 51.
[0031] [Angle of the inclined support wall] The deformation behavior was simulated when the outer angle α (see Figure 3) that the inclined support walls 57 and 58 make with respect to the outer wall 51 (approximately parallel to the vehicle's longitudinal direction) was varied according to patterns A to D in Table 1 below. The third and fourth columns of Table 1 show the relative values of the maximum bending moment and maximum load acting on the height of the beltline, respectively, expressed with respect to the values of the base pattern. Figure 8 shows the relationship between load and displacement (stroke) for each pattern. From the results, it can be seen that the effect of the inclined support walls 57 and 58 in supporting the outer wall 31 and 51 increases as the outer angle they make with respect to the outer wall 51 increases. Patterns C and D, in particular, show a large effect, reflecting the effective suppression of the indentation of the outer wall 31 and 51. Furthermore, by interpolating the results in the table, it can be seen that if the outer angle is 40 degrees or more, it can support a load equivalent to or greater than that of the base structure. [Table 1]
[0032] [Inclined support wall of the outer member] As shown by the solid lines in Figure 9, in another embodiment, the outer member 130 forming the main member 120 can also be provided with inclined support walls 138 and 139 that connect the front wall 132 and the rear wall 133 in a planar manner (the dashed lines in Figure 9 show the shape without inclined support walls for comparison). In this case, the reinforcing member 50 is joined to the outer member 130 (for example by spot welding) only by the outer wall 51, the front wall 52, and the rear wall 53, and does not need to be welded to the inclined support walls 138 and 139 of the outer member 130.
[0033] Although specific embodiments have been described above, this technology is not limited to those embodiments. Those skilled in the art can make various modifications, substitutions, and improvements. [Explanation of symbols]
[0034] 10 B-pillar 12 Roof side rails 14 Side sill 16 Beltline 20 Main components 30 Outer member 31 Outer wall 32 Front wall 33 Back wall 34, 35 flange 36. Recessed bead 37 Door hinge fixing part 40 Inner component 42, 43 flanges 50 Reinforcement members 51 Outer wall 52 Front wall 53 Back wall 54 Welding protrusions 56 Recessed bead 57, 58 Slanted support wall 110 B-pillar 120 Main components 130 Outer member 131 External wall 132 Front wall 133 Back wall 138, 139 Slanted support wall 210 B-pillar 220 Main components 250 Reinforcement members 251 External wall 252 Front wall 253 Back wall
Claims
1. It is a vehicle pillar, It comprises a main member having a closed cross-section and a reinforcing member disposed inside the main member, The reinforcing member comprises an outer wall positioned on the outside of the vehicle, a front wall positioned on the front side, a rear wall positioned on the rear side, and inclined support walls that connect the outer wall and the front wall, and the outer wall and the rear wall, in a planar manner in at least a portion of the longitudinal direction of the reinforcing member. A vehicle pillar in which the reinforcing member is welded to the main member at the outer wall, the front wall, and the rear wall.
2. A vehicle pillar according to claim 1, wherein the outer wall of the reinforcing member has a recessed bead extending in the longitudinal direction of the vehicle pillar.
3. A vehicle pillar according to claim 1, wherein the front wall and the rear wall each have a plurality of welding protrusions along the longitudinal direction for welding to the main member, and each of the welding protrusions has a planar welding seating surface.
4. A vehicle pillar according to claim 3, wherein the inclined support wall is in contact with at least one of the plurality of welding protrusions of the front wall and the rear wall.
5. A vehicle pillar according to claim 1, wherein the outer angle formed by the inclined support wall with respect to the outer wall is greater than the outer angles formed with respect to the front wall and the rear wall.
6. A vehicle pillar according to claim 1, wherein the inclined support wall has an outer angle of 40 degrees or more with respect to the outer wall.