Automobile B column structure, door ring assembly and automobile

Abstract

The application relates to a kind of automobile B column structure, door ring assembly and automobile, belong to automobile technical field, solve the poor safety problem under the current automobile B column collision condition, including B column reinforcing plate, the inner side of B column reinforcing plate is fixed with B column inner plate, the inner side of B column reinforcing plate is equipped with reinforcing plate, along by up-to-down direction, the B column reinforcing plate includes sequentially arranged upper reinforcing plate, middle reinforcing plate and lower reinforcing plate, wherein, the thickness of middle reinforcing plate is greater than the thickness of upper reinforcing plate and not greater than the thickness of lower reinforcing plate, simultaneously, the tensile strength of lower reinforcing plate is less than the tensile strength of upper reinforcing plate and middle reinforcing plate, the material breaking elongation of lower reinforcing plate is greater than the material breaking elongation of upper reinforcing plate and middle reinforcing plate, the inner side edge and the outer side edge of lower reinforcing plate at R angle position are all equipped with protruding structure extending towards the inner side of R angle along R angle radial direction to form inducing groove, the B column structure of the application is good under the collision condition.

Description

Technical Field

[0001] This invention relates to the field of automotive technology, specifically to a B-pillar structure, door ring assembly, and automobile. Background Technology

[0002] The statements herein provide only background information in relation to this invention and do not necessarily constitute prior art.

[0003] As a crucial supporting structure in side impacts, the B-pillar's bending can lead to excessive intrusion into the passenger compartment, directly threatening the safety of occupants. Current automotive B-pillars utilize hot-formed steel with low elongation after fracture to achieve high strength, resulting in a structure that is often a single, brittle, ultra-high-strength steel. While this improves intrusion resistance, the material itself has poor toughness, with an elongation after fracture typically only 5%–7%. Under the high impact loads of side-impact pole collisions and moving barrier collisions, the middle section of the B-pillar bears significant impact energy. Brittle cracks and through-thaw tears can easily occur in the welded areas and the main body plate of the middle section, leading to B-pillar bending, excessive intrusion into the passenger compartment, and compromised safety under collision conditions. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a car B-pillar structure, door ring assembly and car, in which the guide groove 8 is set in a graded manner to prevent cracks from spreading upward to the occupant joint protection area in the middle section of the B-pillar, thereby improving the safety of the occupants in the side collision condition.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution: In a first aspect, embodiments of the present invention provide a B-pillar structure for automobiles, including a B-pillar reinforcing plate, an inner B-pillar plate fixed to the inner side of the B-pillar reinforcing plate, and a reinforcing plate provided on the inner side of the B-pillar reinforcing plate. Along the top-to-bottom direction, the B-pillar reinforcing plate includes an upper reinforcing plate, a middle reinforcing plate, and a lower reinforcing plate arranged sequentially. The thickness of the middle reinforcing plate is greater than the thickness of the upper reinforcing plate but not greater than the thickness of the lower reinforcing plate. At the same time, the tensile strength of the lower reinforcing plate is less than the tensile strength of the upper and middle reinforcing plates, and the elongation after fracture of the material of the lower reinforcing plate is greater than the elongation after fracture of the materials of the upper and middle reinforcing plates. The arc surface of the lower reinforcing plate at the R-corner position is provided with a concave structure to form an induction groove.

[0006] Optionally, the upper reinforcing plate has a thickness of 1.3mm-1.5mm, is made of hot-formed steel plate, and has a tensile strength of not less than 1500MPa. The middle reinforcing plate has a thickness greater than that of the upper reinforcing plate, with a thickness of 1.5mm-1.7mm, is made of hot-formed steel plate, and has a tensile strength of not less than 1500MPa. The lower reinforcing plate has a thickness of 1.5mm-1.7mm, is made of hot-rolled pickled steel plate or hot-formed steel plate, and has a tensile strength of not less than 340MPa and an elongation after fracture of not less than 20%.

[0007] Optionally, the depth of the induction groove is 2mm-2.5mm, and the width of the induction groove is 6mm-8mm.

[0008] Optionally, a reinforcing plate is provided on the inner side of the lower reinforcing plate and the middle reinforcing plate, the reinforcing plate covers the inner side of the lower reinforcing plate and the middle reinforcing plate, the top of the reinforcing plate extends to the top of the middle reinforcing plate, and the bottom of the reinforcing plate extends to the bottom of the vertical part of the lower reinforcing plate.

[0009] Optionally, the upper reinforcing plate and the middle reinforcing plate are fixed by laser welding, and the middle reinforcing plate and the lower reinforcing plate are fixed by laser welding.

[0010] Optionally, the inner panel of the B-pillar is composed of an upper panel and a lower panel, which are fixed together by spot welding. The tensile strength of the lower panel is less than that of the upper panel, the thickness of the lower panel is greater than that of the upper panel, and the elongation after fracture of the lower panel is greater than that of the upper panel.

[0011] Optionally, the upper plate is made of hot-formed steel plate with a tensile strength of not less than 1300 MPa and a thickness of 0.8 mm-1.2 mm. The lower plate is made of cold-stamped steel plate with a tensile strength of not less than 780 MPa and a thickness of 1.3 mm-1.5 mm. The elongation after fracture of the lower plate is greater than that of the upper plate, and the elongation after fracture of the lower plate is not less than 12%.

[0012] Optionally, the reinforcing plate has a U-shaped cross-section, including a first reinforcing part and a second reinforcing part integrally disposed on both sides of the first reinforcing part. The outer side of the second reinforcing part is provided with multiple protruding structures to form reinforcing ribs, and the reinforcing ribs are welded and fixed to the inner side of the B-pillar reinforcing plate.

[0013] Optionally, the end of the B-pillar reinforcing plate that mates with the inner B-pillar plate is provided with a first flange distributed along the edge of the B-pillar reinforcing plate, and the end of the inner B-pillar plate that mates with the B-pillar reinforcing plate is provided with a second flange distributed along the edge of the inner B-pillar plate. The first flange and the second flange match each other and are fixed by spot welding.

[0014] Secondly, embodiments of the present invention provide an automotive door ring assembly, which is formed by a B-pillar structure, an A-pillar structure, and a door sill structure 4, wherein the B-pillar structure adopts the automotive B-pillar structure described in the first aspect.

[0015] Thirdly, embodiments of the present invention provide an automobile equipped with the automobile door ring assembly described in the second aspect.

[0016] The beneficial effects of this invention are as follows: The automotive B-pillar structure of this invention features a lower reinforcing plate with a greater elongation at break than the upper and middle reinforcing plates. The thickness of the lower reinforcing plate is set to be no less than that of the middle reinforcing plate to provide structural reinforcement. An induction groove is provided on the arc surface at the radius (R) of the lower reinforcing plate, creating a flexible zone at the bottom and a rigid zone in the middle of the B-pillar structure. During a side impact, the flexible zone significantly improves the toughness of the bottom of the B-pillar structure, allowing it to absorb more energy and ensuring that the deformation pattern remains within a controllable range. This reduces the impact energy received by the middle section of the B-pillar structure, effectively preventing excessive deformation in the Y-direction of the vehicle, which could lead to tearing of the B-pillar structure and welds, as well as brittle cracking. This avoids B-pillar bending and excessive intrusion into the passenger compartment, thus improving safety during collisions.

[0017] The automotive B-pillar structure of this invention features a reinforcing plate covering the inner surfaces of the middle and lower reinforcing plates. Using a single piece of plate, it structurally strengthens the middle section of the B-pillar reinforcing plate, effectively preventing excessive deformation of the B-pillar structure in the Y-direction of the vehicle, thus avoiding tearing of the B-pillar structure and welds, as well as brittle cracking. Simultaneously, the reinforcing plate strengthens the connection between the middle and lower reinforcing plates, preventing weld cracking under collision conditions. Furthermore, the reinforcing plate supports the lower reinforcing plate, preventing excessive deformation under collision conditions and allowing it to slowly crush, absorbing as much collision energy as possible. Attached Figure Description

[0018] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0019] Figure 1 This is a schematic diagram of the overall structure of Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the reinforcing plate arrangement in Embodiment 1 of the present invention; Figure 3 This is a schematic diagram of the reinforcing plate structure in Embodiment 1 of the present invention; Figure 4 This is a schematic diagram of the guide groove set on the arc surface of the reinforcing plate at the R-corner position in Embodiment 1 of the present invention; Figure 5 This is a front view of the inner panel of column B in Embodiment 1 of the present invention; Figure 6 This is a rear view of the inner panel of column B in Embodiment 1 of the present invention; Among them, 1. upper reinforcing plate, 2. middle reinforcing plate, 3. lower reinforcing plate, 4. sill structure, 5. lower A-pillar structure, 6. upper A-pillar structure, 7. reinforcement plate, 8. guide groove, 9. upper plate, 10. lower plate, 11. reinforcing rib. Detailed Implementation

[0020] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0021] Traditional automotive B-pillar structures are mostly made of hot-formed steel sheets of a single strength grade. Although hot-formed steel has high tensile strength, its elongation after fracture is usually only 5% to 7%, and its toughness is poor. Under high impact load conditions such as side pillar collisions or moving barrier collisions, the middle section of the B-pillar sheet is prone to brittle cracks and through-thickness tears, leading to B-pillar bending and excessive passenger compartment intrusion. To address the above-mentioned technical defects, this embodiment proposes an automotive B-pillar structure with a material gradient partition design. By configuring the upper reinforcing plate 1, middle reinforcing plate 2, and lower reinforcing plate 3 of the B-pillar reinforcement plate with different materials and thicknesses, combined with the guide groove 8 set on the arc surface at the R-angle position of the lower reinforcing plate 3, a flexible zone is formed at the bottom of the B-pillar structure. In the event of a collision, the collision deformation is guided to concentrate at the bottom of the B-pillar structure, reducing the collision energy in the middle section of the B-pillar structure and avoiding problems such as brittle cracks and through-thickness tears in the middle section of the B-pillar structure.

[0022] The following describes this implementation method in detail with reference to specific examples: Example 1 This embodiment provides a B-pillar structure for automobiles, such as Figures 1-2 As shown, it includes a B-pillar reinforcement plate, an inner B-pillar plate fixed to the inside of the B-pillar reinforcement plate, and a reinforcing plate 7 disposed on the inner side of the B-pillar reinforcement plate.

[0023] Along the top-to-bottom direction, the B-pillar reinforcement plate adopts a U-shaped structure, including an upper reinforcement plate 1, a middle reinforcement plate 2, and a lower reinforcement plate 3 arranged sequentially. The upper reinforcement plate 1, middle reinforcement plate 2, and lower reinforcement plate 3 are differentiated in terms of material strength, thickness, and elongation after fracture, forming a gradient material distribution from top to bottom. Specifically: The upper reinforcing plate 1 is located above the B-pillar reinforcing plate, corresponding to the main force transmission area in the vehicle roof crush test. In this embodiment, the upper reinforcing plate 1 is made of hot-formed steel plate with a tensile strength of not less than 1500MPa and a microstructure mainly composed of full martensite. In the vehicle roof crush test, the upper reinforcing plate 1, as the main component for transmitting roof load, effectively resists the vertical intrusion when the roof is under pressure through its structural strength, ensuring that the survival space for the occupants' heads meets regulatory requirements.

[0024] The hot-formed steel plate used for the upper reinforcing plate 1 can be any existing steel plate, and will not be described in detail here.

[0025] The middle reinforcing plate 2 is located below the upper reinforcing plate 1. The top end of the middle reinforcing plate 2 is fixedly connected to the bottom end of the upper reinforcing plate 1. In a side impact scenario, the middle reinforcing plate 2 corresponds to the chest and abdominal area of ​​the occupant. The middle reinforcing plate 2 is made of hot-formed steel plate with a tensile strength of not less than 1500MPa. The thickness of the middle reinforcing plate 2 is greater than that of the upper reinforcing plate 1. By appropriately increasing the cross-sectional thickness, the flexural modulus of the middle reinforcing plate 2 is improved compared to that of the upper reinforcing plate 1. This effectively suppresses the intrusion of the middle section of the B-pillar structure into the vehicle under impact load, keeping the deformation of the occupant's chest and abdominal area within a safe threshold.

[0026] Moreover, the thickness of the upper reinforcing plate 1 is less than that of the middle reinforcing plate 2, which allows the upper reinforcing plate 1 to minimize its thickness while meeting strength requirements, saving material usage and achieving lightweight design.

[0027] In this embodiment, the material used to make the middle reinforcing plate 2 is the same as that used to make the upper reinforcing plate 1, and will not be described again here.

[0028] Furthermore, the cross-sectional dimension of the internal cavity of the middle reinforcing plate 1 is larger than that of the internal cavity of the upper reinforcing plate 1. Therefore, the cross-sectional dimension of the cavity of the upper reinforcing plate 1 gradually increases from top to bottom.

[0029] The lower reinforcing plate 3 is located below the middle reinforcing plate 2, corresponding to the B-pillar root area near the threshold. Unlike the upper reinforcing plate 1 and the middle reinforcing plate 2, the lower reinforcing plate 3 is made of a material with a lower tensile strength than the upper reinforcing plate 1 and the middle reinforcing plate 2. The elongation after fracture of the material of the lower reinforcing plate 3 is greater than that of the materials of the upper reinforcing plate 1 and the middle reinforcing plate 2.

[0030] In this embodiment, the lower reinforcing plate 3 is made of hot-rolled pickled steel plate or annealed high-formability hot-formed steel plate. The lower reinforcing plate 3 is made of a material with high elongation after fracture and low tensile strength, which provides sufficient plastic deformation reserve for the area of ​​the lower reinforcing plate 3, so that it does not undergo brittle fracture during large-scale wrinkling deformation. A flexible zone is formed at the bottom of the B-pillar structure. By setting a flexible zone at the bottom of the B-pillar, the collision deformation can be guided to concentrate at the bottom of the B-pillar, so that the energy absorption during the side collision mainly occurs in the area of ​​the lower reinforcing plate 3, reducing the collision energy received by the middle section of the B-pillar structure, and not affecting the occupant core protection zone corresponding to the middle reinforcing plate 2.

[0031] The materials used for the lower reinforcing plate 3 can be existing materials, and will not be described in detail here.

[0032] like Figure 4As shown, the lower reinforcing plate 3 has a concave structure on the arc surface at the R-corner position to form an induction groove 8.

[0033] The R-corner position is the area with the greatest curvature in the cross-section of the lower reinforcing plate 3, and it is also the location where stress concentration is most significant during the collision. By setting an induction groove 8 on the arc surface at the R-corner position, the plastic deformation in this area can be actively guided along a predetermined path during the collision, avoiding random cracking, thereby achieving precise control over the collision failure mode.

[0034] The reinforcing plate 7 is installed on the inner side of the B-pillar reinforcing plate, between the B-pillar reinforcing plate and the inner B-pillar plate.

[0035] The reinforcing plate 7 covers the inner sides of the middle and lower sections of the B-pillar reinforcement plate. By overlapping the double-layer sheet metal, it distributes the collision stress at the opening positions of the B-pillar structure, preventing cracks from extending outward from functional openings such as seat belt holes and wiring harness holes. This effectively suppresses stress concentration and crack initiation and propagation in the opening area. At the same time, the reinforcing plate 7 provides support and reinforcement for the middle and lower sections of the B-pillar reinforcement plate.

[0036] In addition, the reinforcing plate 7 covers the inner sides of the middle reinforcing plate and the lower reinforcing plate. It is made of a single piece of plate. On the one hand, it strengthens the middle section of the B-pillar reinforcing plate, which can effectively prevent excessive deformation of the B-pillar structure in the Y direction of the vehicle, thus preventing tearing of the B-pillar structure and weld points and brittle cracks. On the other hand, the reinforcing plate 7 strengthens the connection between the middle reinforcing plate 2 and the lower reinforcing plate 3, preventing the weld between the middle reinforcing plate 2 and the lower reinforcing plate 3 from cracking under collision conditions. On the other hand, the reinforcing plate 7 supports the lower reinforcing plate 3, preventing the lower reinforcing plate 3 from deforming too quickly under collision conditions, so that the lower reinforcing plate 3 can be crushed slowly and absorb as much collision energy as possible.

[0037] The inner panel of the B-pillar is fixed to the inside of the B-pillar reinforcing plate, and together with the B-pillar reinforcing plate, they enclose a closed cross-sectional cavity structure of the B-pillar structure, which together bear the side collision load.

[0038] The B-pillar reinforcement plate and the inner B-pillar plate are fixed together by the flange structure set on their respective side edges, forming a reliable edge connection and ensuring that the entire B-pillar structure maintains its structural integrity during a collision.

[0039] This embodiment further specifies the material specifications and thickness range of the upper reinforcing plate 1, the middle reinforcing plate 2, and the lower reinforcing plate 3, specifically: The thickness of the upper reinforcing plate 1 is 1.3mm-1.5mm, preferably 1.4mm. The upper reinforcing plate 1 is made of hot-formed steel plate with a tensile strength of not less than 1500MPa and an elongation after fracture of 5%-7%.

[0040] The thickness of the middle reinforcing plate 2 is greater than that of the upper reinforcing plate 1. The thickness of the middle reinforcing plate 2 is 1.5mm-1.7mm, preferably 1.6mm. The middle reinforcing plate 2 is made of hot-formed steel plate with a tensile strength of not less than 1500MPa and an elongation after fracture of 5%-7%.

[0041] The thickness of the middle reinforcing plate 2 is increased by 0.2mm compared to the upper reinforcing plate 1. The purpose is to increase the cross-sectional bending modulus of the middle section of the B-pillar structure under collision load, effectively suppress the intrusion of the middle section of the B-pillar structure into the vehicle during side collision, thereby controlling the deformation of the occupant's chest and abdomen within the safe threshold.

[0042] The thickness of the lower reinforcing plate 3 is not less than the thickness of the middle reinforcing plate 2. In this embodiment, the thickness of the lower reinforcing plate 3 is 1.5mm-1.7mm, preferably 1.6mm. The lower reinforcing plate 3 is made of hot-rolled pickled steel plate or annealed high-formability hot-formed steel plate. The tensile strength of the lower reinforcing plate 3 is less than the tensile strength of the middle reinforcing plate 2 and the upper reinforcing plate 1, and its elongation after fracture is greater than that of the upper reinforcing plate 1 and the middle reinforcing plate 2. In this embodiment, the tensile strength of the lower reinforcing plate 3 is not less than 340MPa, and the elongation after fracture is not less than 20%.

[0043] The lower reinforcing plate 3 is made of a material with high elongation after fracture, which allows it to buffer strain concentration through the plastic flow of the material itself during large-scale wrinkling deformation, without brittle fracture, thereby ensuring that the collision energy is fully absorbed and dissipated in the area of ​​the lower reinforcing plate 3.

[0044] Hot-rolled pickled steel sheets or annealed high-formability hot-formed steel sheets can be made from existing steel sheet materials, which will not be described in detail here.

[0045] In this embodiment, the upper reinforcing plate 1 and the middle reinforcing plate 2 are fixed together by laser welding, and the middle reinforcing plate 2 and the lower reinforcing plate 3 are also fixed together by laser welding.

[0046] Laser welding produces continuous and uniform welds. The heat-affected zone of the weld area is much smaller than that of traditional resistance spot welding. The mechanical properties on both sides of the weld transition smoothly, and there will be no obvious abrupt change in strength or stress concentration at the weld location.

[0047] Compared with spot welding, laser welding can evenly transfer the load between the upper reinforcing plate 1 and the middle reinforcing plate 2, and between the middle reinforcing plate 2 and the lower reinforcing plate 3 along the entire length of the weld, avoiding the concentration of collision load at the weld point, thereby effectively reducing the risk of cracking at the weld.

[0048] Meanwhile, the upper reinforcing plate 1, the middle reinforcing plate 2, and the lower reinforcing plate 3 are fixed by laser welding, eliminating the need for overlapping parts, saving materials, reducing weight, and meeting the requirements of vehicle lightweight design.

[0049] In this embodiment, the specific dimensions of the guide groove 8 at the corner position of the lower reinforcing plate 3R are further defined.

[0050] The depth of the induction groove 8 is 2mm to 2.5mm, and the width of the induction groove 8 is 6mm to 8mm.

[0051] In this embodiment, the guide groove 8 is configured with the above-mentioned dimensions so that the guide groove 8 has a sufficient cross-sectional width to guide the formation of the plastic hinge. At the same time, the side wall of the guide groove 8 and the arc surface of the lower reinforcing plate 3 adopt a rounded transition to avoid stress concentration at sharp corners during the stamping process.

[0052] In this embodiment, the lower reinforcing plate 3 adopts a T-shaped structure, including a vertical part and a horizontal part. The vertical part and the horizontal part are connected by an arc transition, and the arc transition part forms an R-angle. The top of the vertical part is connected to the middle reinforcing plate 2 by laser welding. The horizontal part is used to connect to the sill structure 4 by laser welding. The reinforcing plate 7 matches the inner side of the lower reinforcing plate 3 and the middle reinforcing plate 2, and fits and covers the inner side of the lower reinforcing plate 3 and the middle reinforcing plate 2. The top of the reinforcing plate 7 extends to the top of the middle reinforcing plate 2, and its bottom extends to the bottom of the vertical part of the lower reinforcing plate 3.

[0053] like Figure 2 and Figure 3 As shown, the reinforcing plate 7 covers the areas of the middle reinforcing plate 2 and the lower reinforcing plate 3, and vertically and completely covers all the openings and high-stress bending areas in the middle section of the B-pillar reinforcing plate, so that the functional openings such as the seat belt holes and wiring harness holes of the B-pillar structure are all under the protection of the double-layer sheet metal formed by the reinforcing plate 7 and the B-pillar reinforcing plate.

[0054] Under the action of collision load, the reinforcing plate 7 and the B-pillar reinforcing plate form a double-layer sheet metal structure. By distributing the collision stress at the opening position through the two layers of plates, the stress concentration coefficient at the edge of the hole is significantly reduced, preventing cracks from extending outward from the hole.

[0055] In this embodiment, the reinforcing plate 7 covers the inner side of the vertical portion of the middle reinforcing plate 2 and the lower reinforcing plate 3, and can cover all the openings and high-stress areas of the bending in the middle section of the B-pillar reinforcing plate, thus avoiding the problem of not being able to suppress the spread of hole cracks in the entire area caused by the local reinforcement of the traditional B-pillar structure.

[0056] The cross-section of the reinforcing plate 7 adopts a U-shaped structure that matches the B-pillar reinforcing plate, including a first reinforcing part and a second reinforcing part integrally set on both sides of the first reinforcing part.

[0057] The first reinforcing part forms the middle main body of the reinforcing plate 7, and the second reinforcing part is formed by extending and bending outward from both sides of the first reinforcing part, together with the first reinforcing part forming a U-shaped cross section.

[0058] The first reinforcing part is attached to the inner side of the middle reinforcing plate 2 and the lower reinforcing plate 3. The outer side of the second reinforcing part is provided with multiple protruding structures. The multiple protruding structures are distributed along the extension direction of the second reinforcing part. The protruding structures form reinforcing ribs 11. The reinforcing ribs 11 are spot welded to the inner side of the B-pillar reinforcing plate to fix the reinforcing plate 7 on the inner side of the B-pillar reinforcing plate.

[0059] The preferred welding parameters between the reinforcing plate 7 and the B-pillar reinforcing plate are: welding current of 8.0kA-9.5kA, welding time of 180ms-220ms, and electrode pressure of 3.0kN-3.5kN.

[0060] In this embodiment, after the welding point between the reinforcing plate 7 and the B-pillar reinforcing plate is completed, ultrasonic testing is performed within 3mm of the center of the welding point to ensure that the diameter of the weld nugget is not less than 4.5mm, and that there are no defects such as incomplete welding or open welding, thus ensuring the welding quality.

[0061] The reinforcing plate 7 is made of cold-stamped steel plate with a tensile strength of not less than 780MPa and a thickness of 1.0mm. The U-shaped cross-section design of the reinforcing plate 7 gives it a high moment of inertia, which enhances its bending stiffness. At the same time, the reinforcing ribs 11 on the reinforcing plate 7 not only increase the moment of inertia, but also connect the reinforcing plate 7 and the B-pillar reinforcing plate together by welding and fixing them to the inner side of the B-pillar reinforcing plate. This allows the two to work together to bear the load during a collision, further improving the overall bending performance of the middle and lower sections of the B-pillar structure.

[0062] The inner surfaces of the middle reinforcing plate 2 and the lower reinforcing plate 3 of the B-pillar reinforcement plate are covered with reinforcing plates 7. The reinforcing plates 7 strengthen the middle reinforcing plate 2 and support the lower reinforcing plate 3. In the event of a collision, the lower reinforcing plate 3 will not deform rapidly under the support of the reinforcing plates 7, thus achieving slow crushing at the bottom of the B-pillar structure and absorbing more collision energy.

[0063] In this embodiment, as Figures 5-6 As shown, the inner panel of the B-pillar is composed of an upper panel 9 and a lower panel 10. The upper panel 9 and the lower panel 10 are fixed together by spot welding. The tensile strength of the lower panel 10 is less than that of the upper panel 9, the thickness of the lower panel 10 is greater than that of the upper panel 9, and the elongation after fracture of the lower panel 10 is greater than that of the upper panel 9.

[0064] The partitioned design of the B-pillar inner panel and the segmented design of the B-pillar reinforcement plate complement each other, together forming a material gradient system for the B-pillar structure. The upper panel 9 mainly bears the compressive load under roof crush conditions. High-strength materials are used to ensure that the upper panel 9 does not buckle and become unstable during the roof crush test, thereby ensuring that the roof's compressive strength meets regulatory requirements. The lower panel 10 covers the bottom area of ​​the B-pillar structure, which deforms severely in side impacts and works with the lower reinforcement plate 3 to absorb energy and collapse.

[0065] The lower plate 10 is made of a material with lower tensile strength than the upper plate 9 but higher elongation after fracture. The stiffness loss is compensated by increasing the thickness, so that the section modulus of the lower plate 10 remains basically unchanged under bending load.

[0066] The use of high elongation after fracture material enables the lower plate 10 to buffer strain concentration through the plastic flow of the material itself when subjected to severe torsional deformation, thereby significantly reducing the stress peak around the weld point and effectively suppressing weld point tearing caused by severe deformation of the B-pillar structure.

[0067] The upper plate 9 and the lower plate 10 are connected by spot welding. The distance between the welding line formed by multiple welding points and the bottom end of the B-pillar inner plate is 2 / 3 of the length of the B-pillar inner plate. The side impact deformation at this position of the weld is small and far away from the connection area between the B-pillar inner plate and the seat crossbeam, so as to avoid the weld from having a thermal impact on the surrounding welding points.

[0068] In this embodiment, the specific material specifications and thickness range of the upper plate portion 9 and the lower plate portion 10 of the B-pillar inner panel are further defined, specifically: The upper plate 9 is made of hot-formed steel plate with a tensile strength of not less than 1300MPa, a thickness of 0.8mm-1.2mm, preferably 1mm, and an elongation after fracture of 5%-7%. The use of hot-formed steel plate ensures that the upper plate 9 does not buckle and become unstable during the top pressure test, thereby ensuring that the roof's compressive strength meets regulatory requirements.

[0069] The lower plate 10 is made of cold-stamped steel plate. The tensile strength of the lower plate 10 is less than that of the upper plate 9. In this embodiment, the tensile strength of the lower plate 10 is not less than 780 MPa, and the thickness is 1.3 mm to 1.5 mm, preferably 1.4 mm. The elongation after fracture of the lower plate 10 is not less than 12%. The elongation after fracture of the cold-stamped steel plate is much higher than that of the hot-formed steel plate of the same strength level, so that the lower plate 10 has sufficient plastic deformation reserve under side impact conditions.

[0070] The thickness of the lower plate 10 is increased by 0.4 mm compared to the upper plate 9. The increased thickness compensates for the loss of section modulus caused by the reduction in material strength. At the same time, the use of high elongation cold-stamped steel sheet enables the lower plate 10 to buffer strain concentration through the plastic flow of the material itself when subjected to severe torsional deformation, thereby significantly reducing the stress peak around the weld point and effectively suppressing weld point tearing caused by severe sheet metal deformation.

[0071] In this embodiment, the end of the B-pillar reinforcing plate that mates with the inner B-pillar panel is provided with a first flange distributed along the edge of the B-pillar reinforcing plate, and the end of the inner B-pillar panel that mates with the B-pillar reinforcing plate is provided with a second flange distributed along the edge of the inner B-pillar panel. The first flange and the second flange match each other and are fixed by spot welding. Preferably, the weld points between the first flange and the second flange are arranged in two rows to increase the welding strength. At the same time, structural adhesive is provided at the spot welding position between the first flange and the second flange. While the first flange and the second flange are welded and fixed, they are also bonded and fixed by structural adhesive. The elastic modulus of the structural adhesive is used as a buffer layer to absorb shear deformation.

[0072] In this embodiment, the weld point tearing problem is likely to occur at the bottom of the B-pillar structure during the collision. Therefore, the weld point distribution density between the first flange of the B-pillar reinforcement plate at the R-angle position and the second flange of the B-pillar inner plate is greater than the distribution density of the rest to prevent cracking between the B-pillar inner plate and the B-pillar reinforcement plate.

[0073] The first flange is formed by bending the edge of the B-pillar reinforcement plate outwards, and the second flange is formed by bending the edge of the B-pillar inner panel outwards. During assembly, the two flanges fit together to form an overlapping surface. They are then fixed together by spot welding along the overlapping surface of the first and second flanges. This flange structure increases the overlap area between the B-pillar reinforcement plate and the B-pillar inner panel. Combined with the spot welding connection process, this significantly improves the connection strength and tear resistance between the B-pillar reinforcement plate and the B-pillar inner panel, ensuring that the entire B-pillar structure maintains its structural integrity during a collision.

[0074] In this embodiment, the specific values ​​of tensile strength and elongation after fracture of the upper reinforcing plate 1, the middle reinforcing plate 2, the lower reinforcing plate 3, the upper plate portion 9, and the lower plate portion 10 can be determined according to the actual working conditions, and will not be described in detail here.

[0075] In this embodiment, during a collision, the lateral impact force first acts on the outer surface of the B-pillar reinforcement plate. Because the lower reinforcement plate 3 is made of a material with high elongation after fracture and low tensile strength, and has an induction groove 8 at the radius (R-angle), the impact energy during the collision is preferentially absorbed by the area of ​​the lower reinforcement plate 3. The location of the induction groove 8 is the first to undergo plastic yielding and wrinkling deformation, converting the instantaneous impact peak into the internal energy dissipation of the material. This concentrates the collision deformation in the bottom area of ​​the B-pillar structure, preventing it from spreading upwards to the occupant's core protection area corresponding to the middle reinforcement plate 2. The middle reinforcement plate 2, with its large cross-sectional thickness and ultra-high strength hot-formed steel material, provides strong resistance to intrusion in the occupant's chest and abdomen area during a side impact, maintaining the occupant's survival space. The upper reinforcement plate 1 undertakes the main vertical force transmission task under roof pressure conditions, ensuring that the roof's compressive strength meets regulatory requirements. The reinforcing plate 7 covers the area of ​​the middle reinforcing plate 2 and the lower reinforcing plate 3. During the collision, it forms a double-layer sheet metal stacked structure with the B-pillar reinforcing plate, which distributes the collision stress at the opening position and prevents cracks from extending outward from the functional opening.

[0076] The lower plate 10 of the B-pillar inner panel works in conjunction with the lower reinforcing plate 3 to absorb energy and collapse. The high elongation cold-stamped steel material prevents the lower plate 10 from brittle fracture during severe deformation, while effectively reducing the stress peak around the weld point and suppressing weld tearing. The B-pillar reinforcing plate and the B-pillar inner panel are connected by laser welding of the first and second flanges, ensuring that the entire B-pillar structure participates in the stress as a complete structure throughout the entire collision process, without separation or tearing between the B-pillar reinforcing plate and the B-pillar inner panel.

[0077] Example 2 This embodiment provides an automotive door ring assembly, which is formed by a B-pillar structure, an A-pillar structure, and a door sill structure 4, wherein the B-pillar structure adopts the automotive B-pillar structure described in Embodiment 1.

[0078] The automotive door ring assembly is the core load-bearing structure of the vehicle body side panel, which is formed by the B-pillar structure, A-pillar structure and sill structure together to form a complete side panel door ring frame.

[0079] In this embodiment, the automotive door ring assembly adopts an integrated door ring design, connecting the B-pillar reinforcement plate with the A-pillar structure and the sill structure 4 reinforcement plate using laser welding to form an integrated door ring reinforcement plate assembly. Specifically, one end of the upper reinforcement plate 1 of the B-pillar structure is laser-welded to the top of the upper A-pillar structure 6, and the bottom end is laser-welded to the lower A-pillar structure 5. The lower reinforcement plate 3 of the B-pillar structure is laser-welded to the lower A-pillar structure 5 to fix the sill structure 4.

[0080] The B-pillar reinforcement plate is fixed to the A-pillar structure and sill structure 4 by laser welding, eliminating the need for overlapping, reducing material usage, and lightening the weight of the door ring assembly. Simultaneously, it avoids the problem of the heat-affected zone around the weld point becoming a weak point in the structure, which is caused by spot welding. Welding results in a significant hardening effect, a substantial decrease in the toughness and plasticity of the heat-affected zone, and a tendency for cracks to initiate from the weld edge and propagate towards the sheet metal base material during a collision.

[0081] The upper A-pillar structure 6 and the lower A-pillar structure 5 together constitute the A-pillar structure. The specific structures of the upper A-pillar structure 6, the lower A-pillar structure 5, and the sill structure 4 can be achieved using existing technologies, and will not be described in detail here.

[0082] The B-pillar structure plays a major role in transmitting force and absorbing energy during side impacts within the door ring assembly. The upper reinforcing plate 1 of the B-pillar reinforcement plate corresponds to the load area of ​​the window frame and is made of ultra-high strength hot-formed steel plate, providing strong structural support under side impact and roof crush conditions. The middle reinforcing plate 2 corresponds to the chest and abdomen area of ​​the occupants and effectively suppresses the intrusion of the B-pillar waist bending into the vehicle during side impacts. The lower reinforcing plate 3 connects to the door sill structure 4, is made of high elongation after fracture material, and achieves collapse energy absorption through the guide groove 8 at the R-corner position, confining plastic deformation and cracks within the non-protected area of ​​the lower reinforcing plate 3, and protecting the structural integrity of the core occupant protection area corresponding to the middle reinforcing plate 2.

[0083] The A-pillar structure includes an upper A-pillar structure 6 and a lower A-pillar structure 5. The upper A-pillar structure 6 is located on the upper part of the window frame and bears the main force transmission task under roof-impact conditions. The lower A-pillar structure 5 is located at the lower part of the A-pillar structure and together with the sill structure 4 and the lower reinforcing plate 3 of the B-pillar structure, it forms a closed loop for force transmission at the lower part of the door ring assembly. The sill structure 4 extends longitudinally along the vehicle body, connecting the lower reinforcing plate 3 of the B-pillar structure and the lower A-pillar structure 5. In a side collision, it diverts the lateral impact force borne by the bottom of the B-pillar structure in the forward and backward directions, reducing the concentrated force on the bottom of the B-pillar structure.

[0084] In this embodiment, by connecting the B-pillar structure, A-pillar structure, and sill structure 4 into a whole, the door ring assembly can transfer the impact load along the complete path of the door ring assembly frame during a side collision, making full use of the stiffness and strength reserves of the entire door ring structure, rather than concentrating the load on a single component of the B-pillar structure. This integral force transmission path effectively reduces the local stress peak at any connection point in the B-pillar structure, fundamentally reducing the risk of cracking at the connection point under collision conditions.

[0085] In a side-impact collision, the working process of the automotive door ring assembly in this embodiment is as follows: After the lateral impact force acts on the outer side of the B-pillar reinforcement plate, the impact load is transmitted in both upward and downward directions along the cross-section of the B-pillar reinforcement plate. In the downward direction, the load is transmitted to the sill structure 4 via the connection between the lower reinforcement plate 3 and the sill structure 4, and then distributed along the sill structure 4 in the front-rear direction of the vehicle body; in the upward direction, the load is transmitted to the roof longitudinal beam via the middle reinforcement plate 2 and the upper reinforcement plate 1. During this force transmission process, the lower reinforcement plate 3 absorbs the collision energy through the setting of its flexible zone; the middle reinforcement plate 2, with its high-strength material and large cross-sectional thickness, provides strong intrusion resistance in the chest and abdomen area of ​​the occupants; the reinforcement plate 7 provides full coverage protection for the opening area in the middle section of the B-pillar structure, blocking the path of crack initiation and propagation from the functional opening. The synergistic effect of the integral force transmission frame of the door ring assembly allows the collision energy to be evenly dissipated along the complete door ring path, effectively controlling the intrusion of the passenger compartment and ensuring occupant safety.

[0086] The door ring assembly in this embodiment, whose structure is not described in detail, can be achieved using existing technology and will not be described in detail here.

[0087] Example 3 This embodiment provides a car equipped with the car door ring assembly described in Embodiment 2.

[0088] The automobiles mentioned in this embodiment include, but are not limited to, passenger cars, SUVs, MPVs and other types of passenger vehicles.

[0089] In this embodiment, the vehicle has the door ring assembly described in Embodiment 2 installed on the side of the vehicle body. The door ring assembly provides a complete lateral protection frame for the passenger compartment through the integral enclosure of its B-pillar structure, A-pillar structure, and sill structure 4. The material gradient configuration of the upper reinforcing plate 1, middle reinforcing plate 2, and lower reinforcing plate 3 in the B-pillar structure enables the B-pillar to have sufficient compressive strength under top-impact conditions and can precisely control the deformation mode under side-impact conditions, concentrating the collision energy absorption in the bottom area of ​​the B-pillar structure, while maintaining the structural integrity of the core occupant protection area corresponding to the middle reinforcing plate 2.

[0090] Under a side impact test, the working process of the B-pillar structure of a car equipped with the aforementioned door ring assembly is as follows. When a side impact load is applied to the side of the vehicle body, the lower reinforcing plate 3 of the B-pillar reinforcement plate undergoes controllable plastic deformation first, absorbing the impact energy. The middle reinforcing plate 2, with its ultra-high strength hot-formed steel material and large cross-sectional thickness, provides strong intrusion resistance to the occupant's chest and abdomen area during a side impact, keeping the deformation of the occupant's chest and abdomen within a safe threshold.

[0091] The reinforcing plate 7 provides full coverage protection for the opening area in the middle section of the B-pillar structure, effectively suppressing the initiation of cracks at functional openings such as seat belt holes and wiring harness holes, and preventing cracks from extending outward from the openings and damaging the structural integrity of the reinforcing plate 2.

[0092] Regarding the vehicle's adaptability to various operating conditions, the vehicle in this embodiment utilizes a gradient material zoning design for the B-pillar structure, with ultra-high strength hot-formed steel configurations for the upper reinforcing plate 1 and the middle reinforcing plate 2, and a reinforcing plate 7 on the inner side of the middle reinforcing plate 2. This ensures that the middle and upper sections of the B-pillar structure do not experience through-cracks under high impact conditions such as side pillar collisions. The high elongation after fracture material design of the lower reinforcing plate 3 and the structure design of the induction groove 8 form a flexible zone, ensuring the controllability of collision deformation under collision conditions and guiding the collision energy to the bottom of the B-pillar structure. The B-pillar structure, A-pillar structure, and sill structure 4 are laser-welded together to form an integrated door ring assembly. The integrated force transmission frame of the integrated door ring assembly allows the collision energy to be evenly dissipated along the path of the door ring assembly, reducing the local stress peak of the B-pillar structure under any collision condition.

[0093] In terms of overall vehicle lightweighting, the integrated door ring assembly uses laser welding technology to connect the various sections without overlapping parts. By configuring the thickness of local areas as needed, it avoids the spiral increase in weight caused by the traditional overall thickening solution. While meeting the safety requirements under collision conditions, it effectively controls the overall weight of the B-pillar structure, which meets the overall vehicle lightweighting design goals.

[0094] The remaining structure of the vehicle in this embodiment can be achieved using existing technology, and will not be described in detail here.

[0095] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A car B-pillar structure, comprising a B-pillar reinforcing plate, an inner B-pillar plate fixed to the inner side of the B-pillar reinforcing plate, and a reinforcing plate provided on the inner side of the B-pillar reinforcing plate, characterized in that, Along the top-to-bottom direction, the B-pillar reinforcing plate includes an upper reinforcing plate, a middle reinforcing plate, and a lower reinforcing plate arranged sequentially. The thickness of the middle reinforcing plate is greater than that of the upper reinforcing plate but not greater than that of the lower reinforcing plate. Meanwhile, the tensile strength of the lower reinforcing plate is less than that of the upper and middle reinforcing plates. The elongation after fracture of the material of the lower reinforcing plate is greater than that of the materials of the upper and middle reinforcing plates. The lower reinforcing plate has a concave structure on the arc surface at the R-corner position to form an induction groove.

2. The automotive B-pillar structure as described in claim 1, characterized in that, The upper reinforcing plate has a thickness of 1.3mm-1.5mm, is made of hot-formed steel plate, and has a tensile strength of not less than 1500MPa. The middle reinforcing plate has a thickness greater than the upper reinforcing plate, with a thickness of 1.5mm-1.7mm, is made of hot-formed steel plate, and has a tensile strength of not less than 1500MPa. The lower reinforcing plate has a thickness of 1.5mm-1.7mm, is made of hot-rolled pickled steel plate or hot-formed steel plate, and has a tensile strength of not less than 340MPa and an elongation after fracture of not less than 20%.

3. The automotive B-pillar structure as described in claim 1, characterized in that, The depth of the induction groove is 2mm-2.5mm, and the width of the induction groove is 6mm-8mm.

4. The automotive B-pillar structure as described in claim 1, characterized in that, The inner sides of the lower and middle reinforcing plates are provided with reinforcing plates, which cover the inner sides of the lower and middle reinforcing plates. The top of the reinforcing plate extends to the top of the middle reinforcing plate, and the bottom of the reinforcing plate extends to the bottom of the vertical part of the lower reinforcing plate.

5. The automotive B-pillar structure as described in claim 1, characterized in that, The upper and middle reinforcing plates are fixed by laser welding, and the middle and lower reinforcing plates are fixed by laser welding.

6. The automotive B-pillar structure as described in claim 1, characterized in that, The inner panel of the B-pillar is composed of an upper panel and a lower panel, which are fixed together by laser welding. The tensile strength of the lower panel is less than that of the upper panel, the thickness of the lower panel is greater than that of the upper panel, and the elongation after fracture of the lower panel is greater than that of the upper panel.

7. A car B-pillar structure as described in claim 6, characterized in that, The upper plate is made of hot-formed steel plate with a tensile strength of not less than 1300 MPa and a thickness of 0.8 mm-1.2 mm. The lower plate is made of cold-stamped steel plate with a tensile strength of not less than 780 MPa and a thickness of 1.3 mm-1.5 mm. The elongation after fracture of the lower plate is greater than that of the upper plate, and the elongation after fracture of the lower plate is not less than 12%.

8. The automotive B-pillar structure as described in claim 1, characterized in that, The reinforcing plate has a U-shaped cross-section, including a first reinforcing part and a second reinforcing part integrally set on both sides of the first reinforcing part. The outer side of the second reinforcing part is provided with multiple protruding structures to form reinforcing ribs, and the reinforcing ribs are welded and fixed to the inner side of the B-pillar reinforcing plate.

9. A car B-pillar structure as described in claim 1, characterized in that, The end of the B-pillar reinforcing plate that mates with the inner B-pillar panel is provided with a first flange distributed along the edge of the B-pillar reinforcing plate, and the end of the inner B-pillar panel that mates with the B-pillar reinforcing plate is provided with a second flange distributed along the edge of the inner B-pillar panel. The first flange and the second flange are matched and fixed by laser welding.

10. A car door ring assembly, comprising a B-pillar structure, an A-pillar structure, and a door sill structure, characterized in that, The B-pillar structure adopts the automotive B-pillar structure as described in any one of claims 1-9.

11. A car, characterized in that, The vehicle door ring assembly as described in claim 10 is provided.

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