Automobile body passive safety design method and structure and automobile

Abstract

The invention relates to the technical field of automobile structure design methods, in particular to an automobile body passive safety design method and structure and an automobile. The energy absorption box, the front longitudinal beam and the integrated die-casting forecabin with the determined installation position and size are optimized; performing optimization design on the front longitudinal beam structure based on the installation position of the forecabin; the strength relation of the energy absorption box, the front longitudinal beam and the forecabin is determined according to the mode that the strength of the energy absorption box is smaller than; according to the design requirement, the deformation energy absorption strength range of the energy absorption box, the front longitudinal beam and the forecabin is determined; energy absorption box type selection is carried out based on the strength range of the energy absorption box, the structure of the front longitudinal beam is optimized based on the strength range of the front longitudinal beam, the structure of the forecabin is optimized based on the strength range of the forecabin, and an initial scheme is obtained; and performing simulation evaluation on the initial scheme until the design requirements are met. The vehicle body passive safety design method is simple, the integrally die-cast forecabin is protected to the maximum extent, and the safety of the whole vehicle body during collision is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of automobile structure design methods, and in particular to a vehicle body passive safety design method, structure and automobile. Background Art

[0002] Research shows that for every 10% reduction in vehicle weight, fuel consumption for combustion vehicles can drop by 6% to 8%, CO2 emissions can be reduced by approximately 8.5g / km, and the range of new energy vehicles can be increased by 5% to 8%. Furthermore, the improvements in economy, safety, and comfort brought about by lightweighting will better meet consumer demand, further highlighting the competitive advantage of automakers that adopt lightweighting technology. Therefore, to reduce energy consumption and enhance driving range, lightweighting has become a current priority. The primary technical approach to achieving lightweighting in new energy vehicles is integrated aluminum alloy die-casting for the vehicle body.

[0003] Integrated die-casting is a highly effective manufacturing process that reduces many of the complexities of traditional manufacturing, offering advantages such as lower costs and reduced vehicle weight, thereby increasing the range of new energy vehicles. However, integrated die-cast parts also suffer from poor repairability. Damage to a component requires replacement, resulting in higher repair costs compared to parts manufactured using traditional methods.

[0004] Existing integrated die-cast parts are usually integrated die-cast car bodies, specifically integrated die-cast front cabins. Damage to integrated die-cast front cabins usually occurs when the vehicle collides. When a car collides head-on, the collision force will first impact the front structure of the lower car body. Existing cars generally only improve the collision safety performance of the car by setting a front anti-collision beam, but the effect is poor. In addition, the integrated die-cast front cabin structure is an important component of the lower body frame of the vehicle. While carrying the components of various fields in the front cabin, it also plays the role of absorbing energy and transmitting energy in collisions, and providing sufficient rigidity for the body frame. In the actual design process, there is currently no design for the passive safety of the car body. Often, only the structure of a single component is considered, and the way the car body collapses and absorbs energy during passive safety is not taken into account. When such a car body collides head-on, there is either a problem of being unable to collapse and absorb energy, resulting in personal injury, or even a small collision will cause damage to the integrated die-cast car body, resulting in a substantial increase in repair costs. Summary of the Invention

[0005] The purpose of this application is to solve the shortcomings of the above background technology and provide a vehicle body passive safety design method, structure and vehicle

[0006] The technical solution of the present application is: a vehicle body passive safety design method, which optimizes the energy absorption box, front longitudinal beam and integrated die-cast front cabin with determined installation position and size; optimizes the front longitudinal beam structure based on the installation position of the front cabin; determines the strength relationship of the three in the manner that the strength of the energy absorption box is less than the front longitudinal beam and less than the front cabin; in the low-speed collision with a vehicle speed not greater than a, the energy absorption box is deformed and crushed to absorb energy to maintain the front longitudinal beam and the front cabin without deformation; in the medium-speed collision with a vehicle speed greater than a and not greater than b, the energy absorption box and the front longitudinal beam are deformed and absorbed to maintain the front cabin without deformation; and in the high-speed collision with a vehicle speed greater than b, the energy absorption box and the front longitudinal beam are deformed and absorbed to maintain the front cabin without deformation. During a collision, the energy absorption requirements of the energy absorption box, front longitudinal beam and front cabin are used to determine their deformation and energy absorption strength ranges. The energy absorption box is selected based on its strength range, the structure of the front longitudinal beam is optimized based on its strength range, and the structure of the front cabin is optimized based on its strength range to obtain an initial design scheme for the passive safety of the vehicle body. The initial scheme is simulated and evaluated. If the evaluation results meet the design requirements, the final scheme is output. If the evaluation results do not meet the design requirements, the energy absorption box, front longitudinal beam and front cabin are further optimized until the design requirements are met.

[0007] According to a vehicle body passive safety design method provided in the present application, the method for optimizing the design of the front longitudinal beam structure based on the installation position of the front cabin includes: splitting the front longitudinal beam into a front longitudinal beam front section and a front longitudinal beam rear section based on the principle that the front end of the front cabin is positioned rearward to avoid damage in medium and low speed frontal collisions, and the front longitudinal beam rear section is integrated into the front cabin by one-piece die-casting; the rear end of the front longitudinal beam front section is connected to the front end of the front longitudinal beam rear section.

[0008] According to a vehicle body passive safety design method provided in the present application, the method for optimizing the structure of the front longitudinal beam based on the strength range of the front longitudinal beam includes: based on the strength range of the front longitudinal beam and the requirement that the deformation of the front section of the front longitudinal beam will not squeeze the front cabin under medium and low speed collisions, forming a connection method in which the rear end of the front section of the front longitudinal beam is overlapped to the front end of the rear section of the front longitudinal beam by an annular outer covering; based on the strength range of the front longitudinal beam, determining the number and strength grade of the connecting bolts in the overlap area between the front section of the front longitudinal beam and the rear section of the front longitudinal beam.

[0009] According to a vehicle body passive safety design method provided in the present application, the method for optimizing the structure of the front longitudinal beam based on the strength range of the front longitudinal beam includes: based on the strength range of the front longitudinal beam and the requirement that deformation of the front section of the front longitudinal beam will not damage the front cabin under medium and low speed collisions, the front section of the front longitudinal beam is divided into a first area away from the rear section of the front longitudinal beam and a second area close to the rear section of the front longitudinal beam, and the strength of the first area is lower than the strength of the second area; the strength of the first area is determined based on the strength range of the front longitudinal beam; and the strength of the second area is determined in such a way that the strength of the second area is at least c times the strength of the first area.

[0010] According to a vehicle body passive safety design method provided by the present application, the structure and / or wall thickness and / or material of the front section of the front longitudinal beam are determined based on the strength of the first area and the strength of the second area.

[0011] According to a vehicle body passive safety design method provided in the present application, the method for optimizing the structure of the front compartment based on the strength range of the front compartment includes: based on the strength range of the front compartment, obtaining the number of fracture points on the front compartment and whether the structural form at the fracture point is a crush groove or a reduced thickness.

[0012] According to a vehicle body passive safety design method provided in the present application, the structure of each breaking point on the front cabin is constructed according to the requirement that the strength of the front cabin breaking point gradually increases from front to rear.

[0013] According to a vehicle body passive safety design method provided in this application, an optimization scheme for the partition at the rear end of the front cabin and the die-cast parts behind the partition is constructed based on the requirement that the partition at the rear end of the front cabin and the die-cast parts behind the partition will not break.

[0014] The present application also relates to a vehicle body passive safety structure, which is designed using any of the above-mentioned vehicle body passive safety design methods, including:

[0015] The front cabin is an integrated die-cast component formed by the rear section of the front longitudinal beam, the front wheel housing, the front end of the front floor, the lower front panel and the front dash panel;

[0016] A front longitudinal beam front section, wherein the rear end of the front longitudinal beam front section is overlapped and fixed to the front end of the front longitudinal beam front section;

[0017] An energy absorption box, the energy absorption box being fixed to the front end of the front section of the front longitudinal beam;

[0018] A front bumper, the front bumper being fixedly connected to the energy absorption box;

[0019] The energy absorption box, the front section of the front longitudinal beam and the front cabin increase in strength in response to a frontal collision.

[0020] The present application also provides a vehicle body passive safety structure, characterized in that: the rear end of the front section of the front longitudinal beam is sleeved on the front end of the rear section of the front longitudinal beam to form an overlapping area; a plurality of connecting bolts are passed through the overlapping area to fix the front section of the front longitudinal beam and the rear section of the front longitudinal beam into one body to form the front longitudinal beam.

[0021] According to a vehicle body passive safety structure provided in the present application, a plurality of partitions arranged at intervals along the X direction are provided on the front compartment, and breaking points formed by reducing the material thickness or constructing crush grooves are provided between adjacent partitions. The plurality of breaking points are arranged in a manner in which the strength gradually increases from front to back.

[0022] The present application also relates to a car, which adopts any one of the above-mentioned car body passive safety structures.

[0023] The advantages of this application are as follows: 1. This application provides a design method for vehicle body passive safety. By optimizing the design of the integrated die-cast front cabin, front longitudinal beams, and energy absorption box of the vehicle body, the structural safety of the integrated die-cast front cabin is guaranteed to the greatest extent, so that the integrity of the front cabin is maintained to the greatest extent in a frontal collision, damage is avoided, and subsequent repair costs are reduced. The entire design method is optimized based on the strategy of energy absorption box crushing energy absorption in low-speed collisions, front longitudinal beam deformation energy absorption in medium-speed collisions, and front cabin deformation energy absorption in high-speed collisions. It takes into account both the structural integrity of the front cabin and the safety of the occupants of the vehicle, and has great promotion value.

[0024] 2. To prevent damage to the front cabin due to deformation of the front longitudinal beam during low- and medium-speed collisions, the present invention splits the front longitudinal beam into two sections: a front longitudinal beam section and a rear longitudinal beam section. The rear longitudinal beam section is directly cast on the front cabin. This shifts the center of gravity of the front cabin rearward, thus avoiding the risk of damage during a head-on collision.

[0025] 3. Based on the structure of the front longitudinal beam, the present application determined that the connection between the front and rear sections of the front longitudinal beam is an overlap connection. Based on the strength range of the front longitudinal beam and to avoid squeezing the front cabin during low- and medium-speed collisions, the connection structure of the front and rear sections of the front longitudinal beam was quickly determined, ensuring to the greatest extent possible that no damage will be caused to the front cabin during low- and medium-speed collisions.

[0026] 4. This application uses the strength range of the front longitudinal beam to prevent damage to the front cabin caused by deformation of the front section of the front longitudinal beam. The front section of the front longitudinal beam is divided into two areas. The strength of the first area is lower than that of the second area. In this way, when the first area deforms, the second area remains intact and the deformation will not be transmitted to the front cabin, thereby better protecting the front cabin.

[0027] 5. This application achieves the required strength requirements by changing the wall thickness or material of the front section of the front longitudinal beam. The entire design method is simple and the design structure is easy to implement;

[0028] 6. This application determines the number of front cabin fracture points based on the strength range of the front cabin. This allows for rapid determination of the number of fracture points on the front cabin. The form of the fracture points can be determined based on actual needs or through subsequent simulation optimization. The entire method is very simple, and the constructed front cabin structure can absorb energy through fracture at the fracture points during a high-speed collision.

[0029] 7. This application sets a crumple energy absorption method for the front cabin and designs a fracture point structure based on this method. The resulting front cabin structure can best cope with high-speed frontal collisions, causing the front cabin to fracture and crush from front to back to absorb energy, thereby maximizing the safety of the vehicle occupants.

[0030] 8. In order to ensure the safety of the passengers in the vehicle to the greatest extent possible, the last partition and die-casting of the front cabin are designed to be unbreakable. The resulting front cabin design structure can ensure the safety of the passengers in the vehicle to the greatest extent possible.

[0031] 9. The vehicle body passive safety structure of the present application is simple in structure and can ensure that the front cabin will not be damaged during low- and medium-speed collisions. The integrated die-casting parts remain intact, and subsequent repair costs are low. In addition, it can maximize the safety of the vehicle occupants during high-speed collisions.

[0032] 10. The connection method between the front longitudinal beam front section and the front longitudinal beam rear section of the present invention is simple and the connection strength is guaranteed, which can prevent the deformation of the front longitudinal beam front section from causing damage to the front cabin during low- and medium-speed collisions;

[0033] 11. The present application designs the structure of the front cabin and arranges multiple breaking points, which can absorb crush energy through the breaking of the breaking points to achieve the purpose of protecting the occupants. Moreover, the strength of the breaking points is enhanced successively, so that the direction of the crush energy absorption of the front cabin can be controlled, further improving the safety of the occupants in the vehicle.

[0034] The vehicle body passive safety design method of this application is simple and can quickly construct a suitable front cabin, front longitudinal beam and energy absorption box structure, thereby protecting the integrated die-cast front cabin to the greatest extent, reducing subsequent maintenance costs, and improving the safety of the entire vehicle body during a collision, which has great promotion value. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 : Schematic diagram of the connection structure of the energy absorption box, front longitudinal beam and front cabin of the present application;

[0036] Figure 2 : Schematic diagram of the front cabin structure of this application;

[0037] Figure 3 : Schematic diagram of the front section of the front longitudinal beam and the front cabin partition distribution of the present application;

[0038] Among them: 1 - front cabin; 2 - front longitudinal beam; 3 - energy absorption box; 4 - front bumper;

[0039] 11 - front wheel housing; 12 - front section of front floor; 13 - lower front panel; 14 - front panel;

[0040] 21—front section of front longitudinal beam; 22—rear section of front longitudinal beam;

[0041] 211—first area; 212—second area. DETAILED DESCRIPTION

[0042] The embodiments of the present application are described in detail below, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0043] In the description of this application, it should be understood that the terms "longitudinal", "transverse", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0044] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. Throughout the description of this application, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0045] The present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0046] This application relates to a vehicle body passive safety design method. The vehicle body in this application refers to the front structure of the vehicle body, such as Figure 1 As shown, it includes a front bumper 4, an energy absorption box 3, a front longitudinal beam 2 and a front cabin 1, as shown in FIG. Figure 2 As shown, the front cabin 1 is a die-cast component that is an integrated structure including the front wheel cover 11, the front bottom plate front section 12, the front lower plate 13, and the front baffle 14. The front longitudinal beam 2 is a longitudinal beam arranged along the X direction. The rear end of the front longitudinal beam 2 is fixed to the front cabin 1, the energy absorption box 3 is fixed to the front end of the front longitudinal beam 2, and the front bumper 4 is fixedly connected to the energy absorption box 3. When a head-on collision occurs, the energy of the head-on collision is transferred to the energy absorption box 3, the front longitudinal beam 2 and the front cabin 1 via the front bumper 4. The vehicle body passive safety design method of the present application is to optimize the structure of the energy absorption box 3, the front longitudinal beam 2 and the front cabin 1, and more specifically, to optimize the crush energy absorption structure of the energy absorption box 3, the front longitudinal beam 2 and the front cabin 1.

[0047] The design strategy of a vehicle body passive safety design method of the present application is to avoid deformation of the front cabin 1 as much as possible during medium and low speed collisions. The front cabin 1 is an integrated die-casting. If deformation occurs, the cost of repair and replacement is relatively high. Therefore, it is necessary to maintain the safety and integrity of the front cabin 1 as much as possible during small collisions at medium and low speeds. The energy absorption box 3 and the front longitudinal beam 2 are used to absorb medium and low speed collisions as much as possible; when responding to high-speed collisions, the front cabin 1 also participates in crush energy absorption, but the crush energy absorption of the front cabin 1 needs to ensure the safety of the occupants in the car and will not cause damage to the occupants in the car.

[0048] Specifically, you can follow the steps below:

[0049] S1. Optimize the crash box 3, front longitudinal beam 2, and integrated die-cast front cabin 1 with determined installation positions and dimensions, and optimize the design of the front longitudinal beam 2 structure based on the installation position of the front cabin 1;

[0050] The installation position and installation dimensions of the energy absorption box 3, front longitudinal beam 2 and integrated die-cast front cabin 1 of the present application are determined. During the vehicle design process, the vehicle model is fixed, and the installation position and installation dimensions of the energy absorption box 3, front longitudinal beam 2 and integrated die-cast front cabin 1 are all determined. The passive safety design of the present application is to optimize the crush energy absorption structure of the energy absorption box 3, front longitudinal beam 2 and front cabin 1;

[0051] The installation position of the front cabin 1 is fixed, but the front cabin 1 and the front longitudinal beam 2 are a structure that is fixed together. In fact, the front longitudinal beam 2 can also be integrated with the front cabin 1 by die-casting. However, in this case, once a collision occurs, the front longitudinal beam 2 is deformed, and the integrated die-casting formed by the entire front cabin 1 and the front longitudinal beam 2 is equivalent to being damaged. The overall repair and replacement is very expensive; therefore, the front longitudinal beam 2 and the front cabin 1 are designed as two independent components. In order to facilitate the connection between the front longitudinal beam 2 and the front cabin 1, a connection needs to be designed at the position of the front cabin 1 corresponding to the front longitudinal beam 2. The connection part is usually a raised structure that protrudes toward the front side of the vehicle along the X direction. The front longitudinal beam 2 is connected to the raised structure. The length of the raised structure determines the length of the front longitudinal beam 2. At the same time, the form of the raised structure determines the connection form of the end of the front longitudinal beam 2. The raised structure is a structure die-cast on the front cabin 1. Its length will affect the center of gravity position of the front cabin 1, or the performance of the front cabin 1 during a low-speed collision. For example, the longer the raised structure, the more forward the center of gravity of the front cabin 1 will be, which will easily cause damage during a frontal collision. Otherwise, it will not easily cause damage to the front cabin 1.

[0052] Therefore, the structure of the front longitudinal beam 2 can be optimized by the installation position of the front cabin 1;

[0053] S2. Determine the strength relationship between the three components, such that the strength of the crash box 3 is less than that of the front longitudinal beam 2 and less than that of the front cabin 1; determine the strength range of the crash box 3, front longitudinal beam 2, and front cabin 1 for deformation and energy absorption, based on the requirements that in a low-speed collision with a vehicle speed not exceeding a, the crash box 3 deforms and crushes to absorb energy to maintain the front longitudinal beam 2 and front cabin 1 intact; in a medium-speed collision with a vehicle speed greater than a and not greater than b, the crash box 3 and front longitudinal beam 2 deform and absorb energy to maintain the front cabin 1 intact; and in a high-speed collision with a vehicle speed greater than b, the crash box 3, front longitudinal beam 2, and front cabin 1 deform and absorb energy; select the crash box 3 based on the strength range, and optimize the structure of the front longitudinal beam 2 based on the strength range of the front longitudinal beam 2;

[0054] The selection of the energy absorption box 3 meets the following requirements: the energy absorption box 3 does not deform when the collision speed is less than a1; the energy absorption box 3 deforms when the collision speed is not less than a1 and less than a, where a1 is less than a. The setting of a1 can refer to the national standard for automobile front and rear end protection devices and other standards.

[0055] The passive safety structure of the vehicle body constructed in this application is required to maximize the safety of the front compartment 1 in low- and medium-speed collisions to avoid high repair costs, while also ensuring that the front compartment 1 can protect the vehicle occupants in high-speed collisions. Based on this strategy, a strength gradient is established for the energy absorption box 3, front longitudinal beam 2, and front compartment 1. The strength in this application refers to the strength that the energy absorption box 3, front longitudinal beam 2, and front compartment 1 can withstand when deformed during a frontal collision. Based on the strength of the front compartment 1, the structure of the front compartment 1 is optimized to obtain an initial design plan for the passive safety of the vehicle body.

[0056] The energy absorbing box 3, front longitudinal beam 2 and front cabin 1 designed according to this strategy can absorb energy by relying on the anti-collision beam and the vehicle body exterior trim at extremely low speeds. In a low-speed collision, the energy absorbing box 3 collapses to absorb energy. In a medium-speed collision, the energy absorbing box 3 and the front longitudinal beam 2 deform to absorb energy. In a high-speed collision, the energy absorbing box 3, the front longitudinal beam 2 and the front cabin 1 deform to absorb energy. In a medium- and low-speed collision, the front cabin 1 does not deform. That is, in a low-speed collision, the collision energy of the vehicle is absorbed by the energy absorbing box 3, and only the energy absorbing box 3 needs to be replaced later. In a medium- and low-speed collision, the collision energy of the vehicle is absorbed by the energy absorbing box 3 and the front longitudinal beam 2, and only the energy absorbing box 3 and the front longitudinal beam 2 need to be replaced later, with low maintenance costs. In a high-speed collision, the front cabin 1 deforms to absorb energy, thereby ensuring the safety of the occupants in the vehicle.

[0057] In this application, a1 is 4 km / h, a is 15 km / h, and b is 30 km / h. Of course, they are not limited to the above values, as long as they can meet the set requirements;

[0058] After obtaining the model of the energy absorption box 3, the optimized design scheme of the front longitudinal beam 2, and the optimized design scheme of the front cabin 1, the initial scheme is formed;

[0059] S3. Perform simulation evaluation on the initial solution. If the evaluation result meets the design requirements, output the final solution. If the evaluation result does not meet the design requirements, perform a step-by-step optimization on the energy absorption box 3, the front longitudinal beam 2, and the front cabin 1 until the design requirements are met.

[0060] Through iterative simulation analysis, a vehicle body passive safety design solution that meets the design requirements can be obtained. The design requirements for this case are that in low- and medium-speed collisions, the energy absorption box 3 and / or the front longitudinal beam 2 deform to absorb energy while the front cabin 1 remains unchanged. In high-speed collisions, the energy absorption box 3, the front longitudinal beam 2, and the front cabin 1 deform to absorb energy to ensure the safety of the vehicle occupants.

[0061] In some embodiments of the present application, this embodiment optimizes the above-mentioned step S1. Specifically, the method for optimizing the design of the front longitudinal beam 2 structure based on the installation position of the front cabin 1 is as follows: based on the principle that the front end of the front cabin 1 is positioned rearward to avoid damage in medium and low speed frontal collisions, the front longitudinal beam 2 is split into a front longitudinal beam front section 21 and a front longitudinal beam rear section 22. As mentioned above, the shorter the length of the raised structure connecting the front cabin 1 and the front longitudinal beam 2 (actually the front end position of the front cabin 1), the more rearward the center of gravity of the front cabin 1, and the less likely it is to be damaged during a frontal collision. Conversely, the more likely it is to be damaged. Therefore, according to this principle, the front longitudinal beam 2 is split into a front longitudinal beam front section 21 and a front longitudinal beam rear section 22. In fact, the front longitudinal beam rear section 22 is the raised structure. The front longitudinal beam rear section 22 is integrated into the front cabin 1 by integral die-casting. It serves as a part of the front longitudinal beam 2 and can connect the connection between the front longitudinal beam 2 and the front cabin 1, which is equivalent to simplifying the connection relationship between the front longitudinal beam 2 and the front cabin 1.

[0062] The front longitudinal beam 2 is a longitudinal beam structure along the X direction. The front longitudinal beam front section 21 and the front longitudinal beam rear section 22 are both arranged along the X direction. The rear end of the front longitudinal beam front section 21 is connected to the front end of the front longitudinal beam rear section 22 .

[0063] Considering the structure of the front longitudinal beam 2, which is a beam structure extending along the X-direction, a socket connection is typically used to ensure the stability of the connection between the front longitudinal beam front section 21 and the front longitudinal beam rear section 22. Since the front longitudinal beam 2 is a tubular beam structure, a socket connection with bolts is the most readily conceivable connection method. Therefore, in this embodiment, the rear end of the front longitudinal beam front section 21 is overlapped with the front end of the front longitudinal beam rear section 22 through an annular outer covering. An overlap region exists between the front longitudinal beam front section 21 and the front longitudinal beam rear section 22. The area of this overlap region, or the length along the X-direction, can be determined based on the length of the front longitudinal beam rear section 22. The length of the front longitudinal beam rear section 22 can be determined based on the installation position of the front cabin 1 and the requirements for low and medium speed collisions.

[0064] The connection between the front longitudinal beam front section 21 and the front longitudinal beam rear section 22 must meet a design requirement: deformation of the front longitudinal beam front section 21 in low- and medium-speed collisions will not squeeze the front compartment 1. This requirement is to prevent deformation of the front longitudinal beam front section 21 and squeezing the front compartment 1 in low-speed collisions. The front compartment 1 here includes the front longitudinal beam rear section 22. In other words, in low-speed collisions, the front longitudinal beam front section 21 will deform, but the front longitudinal beam rear section 22 will not. This requires that the strength of the front longitudinal beam rear section 22 is greater than that of the front longitudinal beam front section 21, and the connection strength between the front longitudinal beam front section 21 and the front longitudinal beam rear section 22 is also greater than that of the front longitudinal beam front section 21. Therefore, the strength range of the front longitudinal beam front section 21 can be used to determine the number and strength grade of the connecting bolts in the overlap area. Generally, the number of connecting bolts is as large as possible. During the design process, the number of connecting bolts can exceed 12.

[0065] In a further embodiment of the present application, the present embodiment optimizes the above-mentioned step S2. Specifically, the method for optimizing the structure of the front longitudinal beam 2 based on the strength range of the front longitudinal beam 2 is as follows: based on the strength range of the front longitudinal beam 2 and the requirement that the deformation of the front longitudinal beam front section 21 will not damage the front cabin 1 under medium and low speed collisions, Figure 3 As shown, the front longitudinal beam front section 21 is divided into a first area 211 away from the front longitudinal beam rear section 22 and a second area 212 close to the front longitudinal beam rear section 22, and the strength of the first area 211 is lower than the strength of the second area 212; the strength of the first area 211 is determined based on the strength range of the front longitudinal beam 2; and the strength of the second area 212 is determined in such a way that the strength of the second area 212 is at least c times the strength of the first area 211.

[0066] During low and medium speed collisions, especially medium speed collisions, the front longitudinal beam front section 21 will deform. To prevent the deformation of the front longitudinal beam front section 21 from causing the deformation of the front longitudinal beam rear section 22, i.e., the front cabin 1, the embodiment divides the front longitudinal beam front section 21 into sections. Figure 3 As shown, the strength of the first area 211 is lower than that of the second area 212. During a low-speed or medium-speed collision, the first area 211 has a low strength and quickly deforms to produce a crumple energy-absorbing effect. However, the second area 212 has a high strength and will not deform during a low-speed or medium-speed collision. The deformation of the front section 21 of the front longitudinal beam will not cause the deformation of the rear section 22 of the front longitudinal beam, and will not cause damage to the integrated die-cast part of the front cabin 1.

[0067] During the actual design process, since the strength range of the front longitudinal beam 2 is obtained, the strength of the first region 211 can be determined based on this strength range of the front longitudinal beam 2. The strength of the first region 211 and the strength of the second region 212 are in a multiple relationship, and the strength of the second region 212 can be obtained from the strength of the first region 211. The above multiple c is 1.5 (not limited to this value).

[0068] The strength of the front longitudinal beam section 21 has been determined. Since the dimensions of the front longitudinal beam section 21 are fixed, the strength of the front longitudinal beam section 21 can be adjusted by adjusting the wall thickness and material. The wall thickness or material of the front longitudinal beam section 21 is determined based on the strength of the first region 211 and the strength of the second region 212.

[0069] The crush energy absorption structure of the front section 21 of the front longitudinal beam has been preliminarily determined.

[0070] In other embodiments of the present application, this embodiment optimizes the above-mentioned step S2. Specifically, the method for optimizing the structure of the front cabin 1 based on the strength range of the front cabin 1 is: based on the strength range of the front cabin 1, the number of fracture points on the front cabin 1 and the structural form at the fracture point are obtained as a crush groove or thickening.

[0071] After determining the strength range of the front cabin 1, the strength can be adjusted by setting partitions and breaking points. Multiple partitions are arranged in sequence along the X direction, such as Figure 3 C1, C2, C3, C4, C5, and C6 are shown. E1 in the diagram is the front bracket clevis mounting point. Breakpoints are set between adjacent compartments. The more compartments and breakpoints there are, the lower the strength of the front compartment 1 will be. Conversely, the stronger the front compartment 1 will be. However, the strength of the front compartment 1 cannot be too high. If it is too high, it will not be able to collapse and absorb energy, thus failing to protect the occupants. If it is too low, it will easily deform, resulting in high repair and replacement costs. Therefore, the strength range of the front compartment 1 meets both of the above requirements.

[0072] The fracture points of the front cabin 1 are fixed. This means that they must be formed on the integral die-cast component. This is achieved by constructing crush grooves between compartments or by reducing the thickness of the material between compartments. This creates weak points between compartments. When the energy of a high-speed collision is transmitted to the front cabin 1, these weak points, or fracture points, fracture and deform, absorbing the collision energy and achieving the desired crushing effect. Once the strength range of the front cabin 1 is determined and the fracture point structure is finalized, the corresponding number of compartments and fracture points can be determined.

[0073] At the same time, because the energy absorption strategy of the present application is to avoid damage to the occupants in the vehicle, it is required that the deformation of the front cabin 1 is that the front part deforms first and the rear part does not deform as much as possible. That is to say, the constructed breaking point needs to meet the requirement that the strength of the breaking point of the front cabin 1 gradually increases from front to back. Based on this requirement and the number of breaking points obtained above and the strength range of the front cabin 1, the structure of each breaking point can be obtained, which is actually the strength requirement of each breaking point. Then the structural form of the breaking point is determined, and the specific structure of the breaking point can be obtained based on the strength of the breaking point.

[0074] Furthermore, to ensure the safety of the vehicle's occupants, and to prevent deformation of the front compartment 1 and potential injury to the occupants in the event of a collision at extreme vehicle speeds, the rearmost partition of the front compartment 1 and the die-casting behind it must not break. This approach allows for the optimization of the rearmost partition of the front compartment 1 and the die-casting behind it. This rearmost partition of the front compartment 1 and the die-casting behind it are close to the passenger compartment and must be protected from deformation. Therefore, this structural design can be optimized by increasing the material thickness and reinforcing ribs.

[0075] The design requirements for the front cabin in this embodiment are that when the collision speed is less than b, the front cabin will not be deformed, thereby protecting the high-value integrated die-cast front cabin. In the case of a high-speed collision when the collision speed is not less than b, the surrounding area of the shock absorber tower seat of the front cabin will bend and deform to absorb the energy of the high-speed collision, and the front area behind the shock absorber tower seat cannot be broken, thereby achieving the protection effect for the occupants in the vehicle under high-speed collision.

[0076] In other embodiments of the present application, this embodiment optimizes the above-mentioned step S3. According to the above-mentioned method, this application can obtain an initial scheme formed by the combination of the model of the energy absorption box 3, the crush energy absorption structure of the front longitudinal beam 2, and the crush energy absorption structure of the front cabin 1, and import these initial schemes into the simulation software. The simulation software is used to perform a collision test on the initial scheme, and the collision process under three vehicle speeds is tested. The results are analyzed to see whether they meet the above-mentioned design requirements. If they meet the requirements, the scheme can be output as an optimized scheme. If they do not meet the requirements, the model of the energy absorption box 3, the crush energy absorption structure of the front longitudinal beam 2, and the crush energy absorption structure of the front cabin 1 are further optimized until an optimized scheme that meets the design requirements is obtained.

[0077] This application also relates to a vehicle body passive safety structure, such as Figure 1 and 2 As shown, the vehicle body safety structure of the present application includes a front cabin 1, a front longitudinal beam front section 21, an energy absorption box 3 and a front bumper 4. The front cabin 1 is an integrated die-cast component of the front longitudinal beam rear section 22, the front wheel cover 11, the front floor front end 12, the front wall lower plate 13 and the front wall baffle 14. The rear end of the front longitudinal beam front section 21 is overlapped and fixed to the front end of the front longitudinal beam front section 21, the energy absorption box 3 is fixed to the front end of the front longitudinal beam front section 21, and the front bumper 4 is fixedly connected to the energy absorption box 3. The energy absorption box 3, the front longitudinal beam front section 21 and the front cabin 1 increase in strength in response to a head-on collision.

[0078] Among them, the rear end of the front longitudinal beam front section 21 is sleeved on the front end of the front longitudinal beam rear section 22 to form an overlapping area, and a plurality of connecting bolts are passed through the overlapping area to fix the front longitudinal beam front section 21 and the front longitudinal beam rear section 22 into one to form the front longitudinal beam 2.

[0079] The front cabin 1 is provided with a plurality of partitions arranged at intervals along the X direction, and fracture points formed by reducing the material thickness or constructing collapse grooves are provided between adjacent partitions. The plurality of fracture points are arranged in a manner of gradually increasing strength from front to back.

[0080] The present application also provides a car, which adopts the above-mentioned car body passive safety structure.

[0081] like Figure 1 As shown, the X direction of this application is Figure 1 The left side is the front and the right side is the rear.

[0082] The above shows and describes the basic principles, main features, and advantages of the present application. Those skilled in the art should understand that the present application is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present application. Various changes and improvements may be made to the present application without departing from the spirit and scope of the present application. Such changes and improvements are intended to fall within the scope of the present application. The scope of protection claimed in this application is defined by the appended claims and their equivalents.

Claims

1. A vehicle body passive safety design method, characterized by: The crash box, front longitudinal beam, and integrated die-cast front cabin, whose installation positions and dimensions are determined, are optimized; the front longitudinal beam structure is optimized based on the installation position of the front cabin; the strength relationship among the three is determined such that the strength of the crash box is less than that of the front longitudinal beam, which is less than that of the front cabin; the strength range of the crash box, front longitudinal beam, and front cabin deformation energy absorption is determined based on the requirements that in low-speed collisions with a vehicle speed not exceeding a, the crash box deforms and crushes to absorb energy to maintain the front longitudinal beam and front cabin without deformation; in medium-speed collisions with a vehicle speed greater than a and not greater than b, the crash box and front longitudinal beam deform to absorb energy to maintain the front cabin without deformation; and in high-speed collisions with a vehicle speed greater than b, the crash box, front longitudinal beam, and front cabin deform to absorb energy. The initial design plan for the vehicle body passive safety is obtained by selecting the energy absorption box based on its strength range, optimizing the structure of the front longitudinal beam based on its strength range, and optimizing the structure of the front cabin based on its strength range. The initial solution is simulated and evaluated. If the evaluation results meet the design requirements, the final solution is output. If the evaluation results do not meet the design requirements, the energy absorption box, front longitudinal beam and front cabin are optimized in one step until the design requirements are met.

2. The vehicle body passive safety design method according to claim 1, characterized in that: The method for optimizing the design of the front longitudinal beam structure based on the installation position of the front cabin includes: splitting the front longitudinal beam into a front longitudinal beam front section and a front longitudinal beam rear section based on the principle that the front end of the front cabin is positioned rearward to avoid damage in medium and low speed head-on collisions, and integrating the front longitudinal beam rear section into the front cabin by one-piece die-casting; the rear end of the front longitudinal beam front section is connected to the front end of the front longitudinal beam rear section.

3. The vehicle body passive safety design method according to claim 2, characterized in that: The method for optimizing the structure of the front longitudinal beam based on the strength range of the front longitudinal beam includes: forming a connection method in which the rear end of the front longitudinal beam is overlapped to the front end of the rear end of the front longitudinal beam by an annular outer covering based on the strength range of the front longitudinal beam and the requirement that the deformation of the front section of the front longitudinal beam will not squeeze the front cabin under medium and low speed collisions; and determining the number and strength grade of connecting bolts in the overlap area between the front section of the front longitudinal beam and the rear section of the front longitudinal beam based on the strength range of the front longitudinal beam.

4. A vehicle body passive safety design method according to claim 2 or 3, characterized in that: The method for optimizing the structure of the front longitudinal beam based on the strength range of the front longitudinal beam includes: based on the strength range of the front longitudinal beam and the requirement that deformation of the front section of the front longitudinal beam will not damage the front cabin under medium and low speed collisions, dividing the front section of the front longitudinal beam into a first area away from the rear section of the front longitudinal beam and a second area close to the rear section of the front longitudinal beam, and making the strength of the first area lower than the strength of the second area; determining the strength of the first area based on the strength range of the front longitudinal beam; and determining the strength of the second area in such a manner that the strength of the second area is at least c times the strength of the first area.

5. The vehicle body passive safety design method according to claim 4, characterized in that: Based on the strength of the first region and the strength of the second region, the structure and / or wall thickness and / or material of the front section of the front longitudinal member are determined.

6. The vehicle body passive safety design method according to claim 1, characterized in that: The method for optimizing the structure of the front cabin based on the strength range of the front cabin includes: obtaining the number of fracture points on the front cabin and determining whether the structural form at the fracture points is a crush groove or a thickness reduction based on the strength range of the front cabin.

7. The vehicle body passive safety design method according to claim 6, characterized in that: The structure of each breaking point on the front cabin is constructed according to the requirement that the strength of the front cabin breaking point gradually increases from front to back.

8. The vehicle body passive safety design method according to claim 7, characterized in that: According to the requirement that the partition at the rear end of the front cabin and the die-cast parts behind the partition will not break, an optimization plan for the partition at the rear end of the front cabin and the die-cast parts behind the partition is constructed.

9. A vehicle body passive safety structure, characterized by: The structure is designed using any one of the vehicle body passive safety design methods described in claims 1 to 8. include, The front cabin is an integrated die-cast component formed by the rear section of the front longitudinal beam, the front wheel housing, the front end of the front floor, the lower front panel and the front dash panel; A front longitudinal beam front section, wherein the rear end of the front longitudinal beam front section is overlapped and fixed to the front end of the front longitudinal beam front section; An energy absorption box, the energy absorption box being fixed to the front end of the front section of the front longitudinal beam; A front bumper, the front bumper being fixedly connected to the energy absorption box; The energy absorption box, the front section of the front longitudinal beam and the front cabin increase in strength in response to a frontal collision.

10. The vehicle body passive safety structure according to claim 9, characterized in that: The rear end of the front longitudinal beam front section is sleeved on the front end of the front longitudinal beam rear section to form an overlap area; a plurality of connecting bolts are passed through the overlap area to fix the front longitudinal beam front section and the front longitudinal beam rear section into one body to form the front longitudinal beam.

11. The vehicle body passive safety structure according to claim 9, characterized in that: The front cabin is provided with a plurality of partitions arranged at intervals along the X direction, and fracture points formed by reducing the material thickness or constructing a collapse groove are provided between adjacent partitions. The plurality of fracture points are arranged in a manner in which the strength gradually increases from front to back.

12. An automobile, characterized in that: The automobile adopts any one of the vehicle body passive safety structures described in claims 9 to 11.

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