Small-offset collision sideslip type structure and design method thereof

Abstract

The invention provides a small-offset collision sideslip type structure and a design method thereof.The design method comprises the steps that firstly, the structure at the front end of a working condition is divided into three force transmission paths, namely, the upper force transmission path (shotgun force transmission path), the middle force transmission path (front longitudinal beam force transmission path) and the lower force transmission path (auxiliary frame force transmission path), and the three force transmission paths are clear in hierarchy; the three force transmission paths are communicated through a front end stand column, and the three force transmission paths are globally designed; then, relevance design is conducted on the structures of the three force transmission paths and a sideslip type deformation mode, and specified design is conducted on the percentage ratio of the structure edges of the front ends of the three force transmission paths to the vehicle width; and finally, designing the collision fracture sequence of the front suspension. According to the method, all structures at the front end of the vehicle are fully utilized to participate in the small offset collision, the structure utilization rate is improved, meanwhile, the pressure of weight and cost on reinforcement of the passenger compartment in the small offset collision working condition is reduced, and a set of complete design thought, method and technical route is formed.

Description

Technical Field

[0001] The present invention relates to the field of automobile passive safety collision, and in particular to a small-offset collision side-slip structure and a design method thereof. Background Art

[0002] The 25% frontal small offset collision condition is the collision test condition of the "China Insurance Automobile Safety Index". This condition is set after summarizing the statistical data of traffic collision accidents across the country. In this test condition, the overlap between the rigid barrier and the vehicle width is 25%, that is, only 25% of the vehicle's front structure can participate in collision energy absorption (usually the longitudinal beam does not participate in deformation energy absorption). This collision condition is more stringent in assessing the vehicle body. By measuring the deformation of the vehicle body after the collision test, the structural deformation of the vehicle is graded and evaluated into "excellent", "good", "general", and "poor". The collision test results are publicly released to the public and have become an important safety design goal for each OEM in the development of new models. Figure 1 As shown, the passengers in the driver's side collision are the driver and the passenger behind the driver, and the passengers in the passenger side collision are the driver, the front passenger, and the passenger behind the front passenger. The deformation of the vehicle body after the collision is measured and graded according to the test procedures.

[0003] The 25% small offset frontal collision condition is mainly divided into two technical routes: hard-resistance deformation mode and side-slip deformation mode. The hard-resistance deformation mode does not have high design requirements for the direction and layout of the front-end force transmission path. It mainly makes the body passenger compartment structure such as the A-pillar and the door sill strong enough to resist the small-area impact of the rigid barrier on the passenger compartment structure. It is represented by the design of Japanese and most European car brands; the side-slip deformation mode has high design requirements for the direction and layout of the front-end force transmission path. Through the design of the direction and overlap of each structure, the vehicle has a lateral pushing force, and the collision disconnection moment of each front suspension structure is designed and controlled to achieve the side-slip deformation mode. Because the vehicle body will maintain a certain speed after the collision, the initial kinetic energy is not completely converted into the deformation energy of the vehicle body during the collision, that is, the impact load on the A-pillar and door sill is relatively smaller, and there is no need to design the A-pillar and door sill to be too strong.

[0004] The technical characteristics of the side-slip deformation mode require a more ingenious design of the direction and overlap of the front-end structures. However, the design level of each automobile manufacturer for this technology varies or the focus is only on the specific structure of the vehicle body or the frame. The focus is relatively single, resulting in an incomplete overall design concept and ultimately a poor side-slip collision design effect. The existing technology has the following shortcomings in the design of the relevant working conditions of the front 25% small offset collision: (1) The front-end structure of the vehicle is not fully considered in planning the various force transmission paths, and only focuses on the load transmission of one or two force transmission paths and the overlap form of the final structure; (2) The structural characteristics are not linked to the side-slip deformation mode, and the technical relevance of each structure to the side-slip structure is not designed and explained; (3) The relevance of the suspension fracture sequence to the side-slip deformation mode is not explained; (4) The overall concept and design method of the side-slip design are not explained. Therefore, a more scientific and feasible design method for the side-slip structure of the small offset collision is urgently needed. Summary of the Invention

[0005] In response to the defects in the prior art, the purpose of the present invention is to provide a small-offset collision side-sliding structure and a design method thereof, which utilizes the various structures at the front end of the vehicle to participate in small-offset collisions, improves the structural utilization rate, and at the same time reduces the weight and cost pressure brought by the reinforcement of the passenger compartment in small-offset collision conditions.

[0006] In order to achieve the above technical effects, the present invention adopts the following technical solutions:

[0007] According to a first aspect of the present invention, a method for designing a small offset collision side-slip structure is provided, which specifically comprises the following steps:

[0008] Step S1. The front cabin structure is divided into an upper force transmission path L1, a middle force transmission path L2, and a lower force transmission path L3. The upper force transmission path L1 is the force transmission path of the shotgun beam structure, the middle force transmission path L2 is the force transmission path of the front longitudinal beam structure, and the lower force transmission path L3 is the force transmission path of the front subframe. The height difference between the three force transmission paths is greater than 50 mm, and they are independent of each other and do not cross each other. The three force transmission paths are connected by the front column structure.

[0009] Step S2. Upload force path L1 structural design: Design the distance D1 from the front end outer edge of the shotgun beam to the vehicle centerline to be 25% to 30% of the vehicle width;

[0010] Step S3. Design the structure of the middle force transmission path L2: Design the distance D2 from the front outer edge of the front longitudinal beam structure to the vehicle centerline to be 30% to 35% of the vehicle width;

[0011] Step S4. Design the structure of the lower force transmission path L3: Design the distance D3 from the front outer edge of the subframe to the vehicle centerline to be 30% to 35% of the vehicle width;

[0012] Step S5. The collision fracture sequence of the front suspension connection points is designed from front to back as follows: the front end inner connection point of the front suspension lower arm > the fixed connection point on the front suspension steering knuckle > the front suspension steering rod mounting inner connection point > the rear end inner connection point of the front suspension lower arm.

[0013] Preferably, the front longitudinal beam structure includes a longitudinal beam and an energy absorption box screwed to the front longitudinal beam, but does not include a cross beam and an anti-collision beam.

[0014] Preferably, the structural design in steps S2 to S4 is obtained through simulation.

[0015] According to a second aspect of the present invention, there is provided a small offset collision side-sliding structure designed using the above-mentioned design method for the small offset collision side-sliding structure.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The present invention fully utilizes the participation of various structures at the front end of the vehicle in small offset collisions, thereby improving the structural utilization rate and reducing the weight and cost pressures on the passenger compartment reinforcement in small offset collision conditions, thereby forming a complete set of small offset collision side-slip structure design ideas, methods and technical routes. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0019] Figure 1 This is a schematic diagram of a 25% offset frontal collision condition in the prior art;

[0020] Figure 2 Schematic diagram of the global force transmission path design of the front cabin structure described in the first embodiment;

[0021] Figure 3 Schematic diagram of the design of the structural width of the uploading force path described in the first embodiment;

[0022] Figure 4 Schematic diagram of the design of the structural width of the middle force transmission path described in the first embodiment;

[0023] Figure 5 Schematic diagram of the design of the structural width of the lower force transmission path described in the first embodiment;

[0024] Figure 6 Schematic diagram of the structure of the key connection points in the front suspension described in the first embodiment;

[0025] Figure 7Schematic diagram of the flow of the design method of the small offset collision side-sliding structure described in the first embodiment;

[0026] Figure 8 This is a schematic diagram of a simulated collision when D1 is greater than 30% of the vehicle width as described in the first embodiment;

[0027] Figure 9 This is a schematic diagram of a simulated collision when D1 is 25% to 30% of the vehicle width as described in the first embodiment. DETAILED DESCRIPTION

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Generally, the components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0029] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for protection, but merely represents selected embodiments of the present application. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments in the present application without creative work are within the scope of protection of the present application.

[0030] It should be noted that similar numbers and letters represent similar items in the following figures. Therefore, once an item is defined in one figure, it does not need to be further defined or explained in subsequent figures. In addition, all directional indications in this application (such as up, down, left, right, front, back, bottom...) are only used to explain the relative position relationship, movement, etc. between the components under a specific posture (as shown in the figures). If the specific posture changes, the directional indication will also change accordingly. Furthermore, the descriptions of "first", "second", etc. in the application are for descriptive purposes only and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features.

[0031] First embodiment

[0032] This embodiment provides a design method for a side-slip structure in a small-offset collision. Based on the collision characteristics of a 25% frontal small-offset collision condition, a unique design is specifically made for the side-slip structure: first, starting from the overall planning of the force transmission path layout, in order to achieve a collision side-slip deformation mode, the structure at the front end of the condition is first divided into three force transmission paths, namely the upper force transmission path (shotgun force transmission path), the middle force transmission path (front longitudinal beam structure force transmission path), and the lower force transmission path (subframe force transmission path), and a global design is performed; then, the structures of the three force transmission paths are correlated with the side-slip deformation mode, and the structures on each force transmission path are all involved in the deformation of the small-offset collision, and the percentage of the structural edge of the front end of the three force transmission paths and the vehicle width is specified and designed; finally, the collision fracture sequence of the front suspension is designed to obtain the optimal side-slip deformation mode. Specifically, the following steps are included:

[0033] Step S1. Starting from the global design of the front cabin structure, in order to achieve a better small offset side-slip deformation mode, such as Figure 2 As shown, the front compartment structure is divided into an upper force path L1, a middle force path L2, and a lower force path L3, with a pillar L0 connecting the three force paths. The upper force path L1 includes the shotgun beam, the middle force path L2 includes the crash box and front longitudinal beam, and the lower force path L3 includes the subframe. All three force paths are designed for small-offset collision conditions early in vehicle design to provide the vehicle with pushing forces in the Y direction and crushing forces in the X direction. The height difference between the three force paths is at least 50 mm, and they are clearly layered and do not overlap.

[0034] Step S2. Upload force path L1 structure design: Figure 3 As shown in the figure, the structure on the force path is designed based on the structural width. The distance D1 from the outer edge of the front structure of the shotgun to Y0 (the vehicle centerline) is A%~B% of the vehicle width (i.e. 25%~30%). During the early design of the shotgun, the outermost side of the cavity structure at the front end of the shotgun beam, the Y-direction distance D1 from Y0 (the vehicle centerline) is greater than 30% of the vehicle width. Figure 8 As shown in the following figure, in the simulation analysis of a small offset collision, the shotgun structure failed to offset the vehicle body and guide the sliding structure in the Y direction. The passenger compartment, especially the A-pillar structure, experienced significant deformation, resulting in severe deformation of the passenger compartment (150 milliseconds at the time of collision). This failed to protect the occupants and did not meet the design and development requirements. By improving the shotgun structure, the Y distance of the outermost side of the front structural cavity from Y0 (vehicle centerline) was controlled to between 25% and 30% of the vehicle width. The small offset collision simulation analysis was repeated. Figure 9, achieving a better side-slip collision mode, reducing the impact on the A-pillar and passenger compartment under this collision condition, and can protect the occupants in the car (150 milliseconds after the collision).

[0035] Step S3. Design of the structure of the force transmission path L2: Figure 4 As shown, the structure along the central force transmission path is designed based on the structural width. The distance D2 from the front end of the front longitudinal beam to Y0 (the vehicle centerline) is designed to be C% to D% of the vehicle width (i.e., 30% to 35%). The front longitudinal beam includes the longitudinal beam, the cavity structure welded to the front end of the longitudinal beam, and the energy absorption box bolted to the front longitudinal beam. It does not include the crossbeam or anti-collision beam.

[0036] Step S4. Design of the lower force transmission path L3 structure: Figure 5 As shown, the structure in the lower force transmission path is designed based on the structural width. The distance D3 from the front outer edge of the subframe to Y0 (the vehicle centerline) is designed to be E% to F% of the vehicle width (i.e., 30% to 35%). The front subframe is measured at the outermost edge of the subframe cavity (close to the vehicle's exterior).

[0037] By designing the correlation between the structures of the three force transmission paths and the side-slip deformation mode in the above steps S2 to S4, the structures on each force transmission path are involved in the deformation of the small offset collision, and the percentage of the structural edge at the front end of the three force transmission paths and the vehicle width is specified and designed, thereby achieving a better Y-direction pushing force in the small offset side-slip deformation mode.

[0038] Step S5. To obtain a better small offset side-slip deformation mode, Figure 6 The collision and disconnection sequence of the four key front suspension connection points shown in the figure is designed, where L4 is the inner connection point at the front end of the lower control arm of the front suspension; L5 is the fixed connection point on the steering knuckle of the front suspension; L6 is the inner connection point for the steering tie rod installation of the front suspension; L7 is the inner connection point at the rear end of the lower control arm of the front suspension; in this embodiment, the collision and disconnection sequence of the above-mentioned key front suspension connection points is designed from front to back as follows: L4>L5>L6>L7, to ensure that in the side-slip collision deformation mode, the wheel can be separated from the vehicle to avoid squeezing of the A-pillar and the door sill, thereby obtaining the best structural deformation collision result.

[0039] In this embodiment, the design method of the small offset collision side sliding deformation mode is described in detail. Figure 7As shown in the figure, the design method formed by the S1 force transmission path design, S2 shotgun width ratio design, S3 front longitudinal beam width ratio design, S4 subframe width ratio design, and S5 front suspension fracture sequence design fully utilizes the participation of various vehicle front-end structures in small offset collisions to improve structural utilization; at the same time, it also reduces the weight and cost pressure brought by the reinforcement of the passenger compartment in small offset collision conditions, forming a complete design idea, method, and technical route for the small offset collision side-slip structure.

[0040] Second embodiment

[0041] This embodiment provides a small-offset side-sliding structure, which is designed using the design method of the small-offset side-sliding structure described in the first embodiment.

[0042] The above describes the specific embodiments of the present invention. Based on the above description, relevant personnel can make various changes and modifications without departing from the scope of the technical concept of this invention.

Claims

1. A design method for a small offset collision side-slip structure, characterized in that: The specific steps include: Step S1. The front cabin structure is divided into an upper force transmission path L1, a middle force transmission path L2, and a lower force transmission path L3. The upper force transmission path L1 is the force transmission path of the shotgun beam structure, the middle force transmission path L2 is the force transmission path of the front longitudinal beam structure, and the lower force transmission path L3 is the force transmission path of the front subframe. The height difference between the three force transmission paths is greater than 50 mm, and they are independent of each other and do not cross each other. The three force transmission paths are connected by the front column structure. Step S2. Upload force path L1 structural design: Design the distance D1 from the front end outer edge of the shotgun beam to the vehicle centerline to be 25% to 30% of the vehicle width; Step S3. Design the structure of the middle force transmission path L2: Design the distance D2 from the front outer edge of the front longitudinal beam structure to the vehicle centerline to be 30% to 35% of the vehicle width; Step S4. Design the structure of the lower force transmission path L3: Design the distance D3 from the front outer edge of the subframe to the vehicle centerline to be 30% to 35% of the vehicle width; Step S5. The collision fracture sequence of the front suspension connection points is designed from front to back as follows: the front end inner connection point of the front suspension lower arm > the fixed connection point on the front suspension steering knuckle > the front suspension steering rod mounting inner connection point > the rear end inner connection point of the front suspension lower arm.

2. The design method of the small offset collision side sliding structure according to claim 1 is characterized in that: The front longitudinal beam structure includes a longitudinal beam and an energy absorption box screwed on the front longitudinal beam, but does not include a cross beam and an anti-collision beam.

3. The design method of the small offset collision side-sliding structure according to claim 1, characterized in that: The structural design in steps S2 to S4 is obtained through simulation.

4. A small offset collision side sliding structure, characterized in that: The invention is designed by adopting the design method of the small offset collision side sliding structure described in any one of claims 1 to 3.

Images