Leg anti-collision beam and control method

Abstract

The invention relates to the technical field of automobiles, in particular to a leg anti-collision beam and a control method. The leg anti-collision beam comprises a buffer mechanism and a leg beam body; the buffering mechanism comprises a cylinder body and a sliding sleeve, the sliding sleeve is connected to the outer side of the cylinder body in a sleeving mode, a sealing cavity is formed in the cylinder body, the leg beam body is installed at the front end of the sliding sleeve, and a front protective grating is installed at the front end of the leg beam body; when a vehicle runs, the sealed cavity is pressurized, the sliding sleeve moves forwards relative to the cylinder body, and the leg beam body protrudes out of the front anti-collision beam forwards; when the vehicle stops, the sliding sleeve moves backwards relative to the cylinder body, and the front protective grating is flush with the front anti-collision beam. Through an adjustable anti-collision beam structure and a corresponding control strategy, the defects of a fixed anti-collision beam in the aspects of collision protection, shape adaptability and maintenance economy are overcome, and dynamic adjustment of the position and the buffering characteristic of the anti-collision beam is achieved.

Description

Technical Field

[0001] This invention relates to the field of automotive technology, and in particular to a leg impact beam and its control method. Background Technology

[0002] In the automotive industry, pedestrian protection is a crucial consideration in vehicle design. Leg protection beams, a key component of pedestrian protection systems, are typically installed at the front of the vehicle to support pedestrians' legs and mitigate injury during a collision.

[0003] Currently, most common leg impact beams adopt a welded assembly structure, which is fixedly installed at the front of the vehicle. This type of structure has the following drawbacks: First, the length of the impact beam in the longitudinal direction of the vehicle is fixed, and in order to ensure the protection effect, it needs to protrude from the front bumper design, affecting the overall integrity and aesthetics of the front of the vehicle; second, the welded assembly has a high degree of integration, and when a part is damaged, the whole assembly needs to be replaced, resulting in high maintenance costs; in addition, the fixed structure cannot dynamically adjust the buffer performance according to the vehicle's driving status, making it difficult to achieve the best energy absorption effect under different collision energy conditions, which not only affects the pedestrian protection effectiveness, but may also lead to more severe damage to vehicle body components. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the purpose of this invention is to provide a leg bumper beam and control method. By using an adjustable bumper beam structure and corresponding control strategies, the deficiencies of fixed bumper beams in terms of collision protection, shape adaptability, and maintenance economy are solved, and the position and buffering characteristics of the bumper beam are dynamically adjusted.

[0005] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions: A leg bumper beam includes a buffer mechanism and a leg beam body. The buffer mechanism includes a cylinder and a sliding sleeve, the sliding sleeve being fitted onto the outside of the cylinder. The cylinder has a sealed cavity, and the leg beam body is mounted on the front end of the sliding sleeve. A front bumper grille is mounted on the front end of the leg beam body. When the vehicle is in motion, the sealed cavity is pressurized, the sliding sleeve moves forward relative to the cylinder, and the leg beam body protrudes forward from the front bumper beam. When the vehicle is stationary, the sliding sleeve moves backward relative to the cylinder, and the front bumper grille becomes flush with the front bumper beam.

[0006] Optionally, a rear end plate is provided at the rear end of the cylinder block, and the rear end plate can be detachably installed on the front end structure of the vehicle body.

[0007] Optionally, the front end of the sliding sleeve has a front end cover, which is detachably mounted on the rear side of the leg beam body.

[0008] Optionally, a rivet nut or a projection weld nut is fixed to the rear side of the leg beam body, and the front end cover is installed in the rivet nut or projection weld nut by screws.

[0009] Optionally, the leg beam body is made of structural steel, steel plate, or composite material.

[0010] Optionally, the cylinder body is filled with a liquid or a gas.

[0011] Optionally, the leg beam body is connected to the front bumper grille by bolts or clips.

[0012] This invention also provides a control method for the leg impact beam as described above, comprising: Real-time vehicle speed data collection; The target pressure value of the medium inside the buffer mechanism is determined based on the pre-stored mapping relationship between the speed range and the pressure value. Adjust the pressure of the medium inside the buffer mechanism to the target pressure value.

[0013] Optionally, when determining the target pressure value, if the vehicle speed crosses a speed range threshold, pressure adjustment is only triggered after the vehicle speed has remained within the new range for a predetermined time.

[0014] Optionally, the mapping relationship between the speed range and the pressure value is constructed in the following way: Divide into multiple speed ranges; For each velocity range, the average collision energy is obtained through collision simulation; The pressure value is calculated based on the average collision energy.

[0015] One or more technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages: 1. In the leg impact beam of the present invention, the buffer mechanism includes a cylinder and a sliding sleeve. The sliding sleeve is fitted onto the outside of the cylinder, and the leg beam body is installed at the front end of the sliding sleeve and connected to the front bumper grille. When the vehicle is in motion, pressurization within the sealed cavity causes the sliding sleeve to move forward relative to the cylinder, protruding the leg beam body forward over the front impact beam, thereby providing leg support for pedestrians during a collision. When the vehicle is stationary, the sliding sleeve moves backward, making the front bumper grille flush with the front impact beam. Existing leg impact beams, due to their fixed length, cannot simultaneously meet the requirements of both the protruding position needed for pedestrian protection and the straightness required for vehicle body styling. This structure, through its extension and retraction movements in both moving and stationary states, ensures the necessary protrusion for pedestrian protection during movement and allows the front bumper grille to be flush with the front impact beam when stationary, thus balancing pedestrian protection and vehicle front-end styling requirements. Furthermore, the separate structure of the buffer mechanism and the leg beam body eliminates the need for complete replacement of existing welded assemblies. If a single component is damaged, it can be repaired and replaced individually, reducing post-collision repair costs.

[0016] 2. Through dynamic speed-pressure adaptation, the buffer mechanism can provide optimal energy absorption under different collision scenarios, improving the accuracy of pedestrian protection. Moreover, targeted pressure adjustment can reduce excessive deformation or excessive rigidity of the buffer mechanism caused by pressure mismatch, extending the service life of the mechanism, while reducing the damage to vehicle body parts in a collision and reducing maintenance costs.

[0017] Advantages of additional aspects of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In addition, the dimensions or spacing between the components are exaggerated to show the position of each component, and the schematic diagrams are for illustrative purposes only.

[0019] Figure 1 This is a schematic diagram of the retractable cushioned leg anti-collision device provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the front bumper grille position when the vehicle is stopped and during driving, provided by an embodiment of the present invention; In the diagram: 10. Leg beam body; 20. Buffer mechanism; 21. Rear end plate; 22. Cylinder block; 23. Sliding sleeve; 24. Front end cover; 30. Front bumper grille position when the vehicle is stationary; 31. Front bumper grille position when the vehicle is in motion. Detailed Implementation 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. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0020] Example 1 As described in the background section, the lack of adjustable length of the leg impact beam in the X-axis (i.e., the longitudinal direction of the vehicle) in existing technologies creates a conflict between functional and aesthetic requirements. On one hand, to meet pedestrian protection requirements, the leg impact beam needs to protrude beyond the front bumper beam in the X-axis direction to ensure timely contact and support of the pedestrian's legs during a collision. On the other hand, to maintain a styling aesthetic at the front of the vehicle, the front bumper is typically required to remain straight. The protruding leg impact beam interferes with this straightness, thus affecting the overall styling of the front of the vehicle. Secondly, because the leg impact beam is a welded assembly, its components are fixed together by welding. When a collision causes partial damage to the leg impact beam, the damaged parts cannot be replaced individually; the entire welded assembly must be repaired and replaced, increasing post-collision repair costs. Furthermore, the fixed structure of the impact beam cannot dynamically adjust its cushioning characteristics according to the vehicle's driving conditions. Under different collision energy conditions at different vehicle speeds, it cannot achieve a match between energy absorption and collision energy, affecting pedestrian protection and potentially leading to excessive damage to vehicle components.

[0021] like Figure 1 As shown, this embodiment proposes a leg impact beam located at the front impact beam position of a vehicle. The leg impact beam includes a buffer mechanism 20 and a leg beam body 10. The buffer mechanism 20 includes a cylinder 22 and a sliding sleeve 23. The sliding sleeve 23 is sleeved on the outside of the cylinder 22. The cylinder 22 has a sealed cavity. The leg beam body 10 is installed at the front end of the sliding sleeve 23, and a front bumper grille is installed at the front end of the leg beam body 10. Figure 2 The front bumper grille is positioned at position 30 when the vehicle is stationary and at position 31 when the vehicle is in motion. When the vehicle is in motion, the sealed cavity is pressurized, the sliding sleeve 23 moves forward relative to the cylinder 22, and the leg beam body 10 protrudes forward from the front bumper beam; when the vehicle is stationary, the sliding sleeve 23 moves backward relative to the cylinder 22, and the front bumper grille is flush with the front bumper beam.

[0022] The sliding sleeve 23 of the buffer mechanism 20 is fitted onto the outside of the cylinder 22, forming a relatively movable assembly relationship. The sealed cavity inside the cylinder 22 provides space for pressure adjustment. The leg beam body 10 is installed at the front end of the sliding sleeve 23 and has a front bumper grille at the front end. This structure makes the components form a complete transmission and protection system. When the vehicle is moving, the sealed cavity is pressurized, and the pressure pushes the sliding sleeve 23 forward relative to the cylinder 22, thereby causing the leg beam body 10 to protrude forward from the front bumper beam. At this time, it can make contact with the pedestrian's leg in advance and provide support during a collision. When the vehicle stops, the pressure in the sealed cavity is released, and the sliding sleeve 23 moves backward relative to the cylinder 22, making the front bumper grille flush with the front bumper beam.

[0023] Existing leg bumper beams, due to their fixed length, cannot simultaneously meet the requirements of both pedestrian protection (protrusion) and vehicle body styling (flatness). This new structure, through its telescopic movement between moving and stationary states, ensures the necessary protrusion for pedestrian protection during movement while simultaneously ensuring the front grille is flush with the front bumper beam when stationary, thus balancing pedestrian protection and front-end styling requirements. Furthermore, the separate structure of the buffer mechanism 20 and the leg beam body 10 eliminates the need for complete replacement of existing welded assemblies. If a single component fails, it can be repaired and replaced individually, reducing post-collision repair costs.

[0024] The position of the anti-collision beam for different vehicle models is determined by the height (Z-direction) of the leg beam body 10 based on the ground line, and then its longitudinal (front and rear X-direction) position is determined based on the shape. In this embodiment, the Z-direction ground clearance of the leg beam body 10 is generally around 940mm, and the X-direction distance from the front bumper is generally around 10mm. After the anti-collision beam position is determined, the collision energy at the leg anti-collision beam position is determined through CAE collision simulation analysis. Then, the internal pressure of the buffer mechanism 20 is determined based on the stroke of the buffer mechanism 20 to match the collision energy and achieve the function of energy absorption and buffering during the collision.

[0025] The cylinder block 22 is provided with a rear end plate 21 at its rear end, and the rear end plate 21 can be detachably installed on the front end structure of the vehicle body.

[0026] The rear end plate 21 serves as the connection medium between the cylinder block 22 and the vehicle body, ensuring stable fixation of the buffer mechanism 20 to the vehicle body. This detachable installation method changes the existing welded fixing method. When the buffer mechanism 20 is damaged, it is not necessary to disassemble other structures at the front of the vehicle body; the buffer mechanism 20 can be removed from the vehicle body for repair or replacement simply by removing the rear end plate 21, simplifying the repair process and reducing repair difficulty. At the same time, this installation method also facilitates adaptation to different vehicle models. By simply adjusting the installation dimensions of the rear end plate 21 according to the front structure of the vehicle body, the buffer mechanism 20 can be installed on different vehicle models, improving the versatility of the components.

[0027] The sliding sleeve 23 has a front cover 24 at its front end, which is detachably mounted on the rear side of the leg beam body 10. The front cover 24 enables the movement of the sliding sleeve 23 to synchronously drive the leg beam body 10 to move. The detachable structure allows the leg beam body 10 and the buffer mechanism 20 to form an independent detachable unit. When the leg beam body 10 is deformed or damaged due to a collision, it is not necessary to replace the entire anti-collision beam assembly. Only the front cover 24 needs to be removed to remove and replace the leg beam body 10, thus reducing maintenance costs.

[0028] The rear side of the leg beam body 10 is fixed with a rivet nut or a projection weld nut, and the front end cover 24 is installed in the rivet nut or projection weld nut by screws.

[0029] Rivet nuts are fixed to the leg beam body 10 using a riveting process, while projection weld nuts are fixed using a projection welding process. Both types of nuts can form a stable internal thread structure on the leg beam body 10, providing a reliable installation base for screw connections. The cooperation between screws and nuts not only ensures the connection strength between the front cover 24 and the leg beam body 10, preventing them from separating during driving or collisions, but also provides convenient disassembly and assembly. During maintenance, the components can be separated simply by unscrewing the screws, without damaging the original structure.

[0030] The leg beam body 10 can be made of structural steel, steel plate, or composite materials. The choice of different materials can be adapted to the needs of different vehicle models. Structural steel has high bending strength and rigidity, steel plate has good formability and cost performance, while composite materials combine lightweight and corrosion resistance.

[0031] The cylinder 22 is filled with a liquid or a gas. Liquid media are incompressible, resulting in uniform and stable pressure transmission, while gaseous media are compressible, providing a gentler buffering effect. For example, vehicles that frequently travel on highways can use a liquid medium, while vehicles that frequently travel in congested urban areas can use a gaseous medium.

[0032] The leg beam body 10 is connected to the front grille by bolts or clips. Bolt connection has high connection reliability and is suitable for scenarios with long-term fixation and large stress. Clip connection has the characteristics of quick assembly and disassembly and is suitable for scenarios that require frequent disassembly.

[0033] Example 2 In real-world scenarios, the collision energy differs significantly between vehicles traveling at low speeds (such as in congested urban areas) and high speeds (such as on suburban expressways). Low-speed collisions involve smaller energy levels; using high-pressure settings would result in an overly rigid buffer mechanism, failing to effectively cushion the impact and potentially increasing the risk of injury to the pedestrian's legs due to the transmitted impact force. It could also cause excessive deformation of the buffer mechanism itself. Conversely, high-speed collisions involve larger energy levels; using low-pressure settings would result in insufficient energy absorption by the buffer mechanism, failing to completely offset the collision energy. This could lead to excessive force on the pedestrian's legs and potentially cause excessive damage to front-end vehicle components, increasing repair costs.

[0034] Based on the above technical problems, a control method for a leg anti-collision beam is proposed, including: real-time acquisition of vehicle speed; determination of the target pressure value of the medium inside the buffer mechanism according to the pre-stored mapping relationship between speed range and pressure value; and adjustment of the pressure of the medium inside the buffer mechanism to the target pressure value.

[0035] The vehicle speed is collected in real time to ensure that the acquired speed information reflects the current driving status of the vehicle. Then, based on the pre-stored mapping relationship between speed range and pressure value, a target pressure value matching the current vehicle speed is found to provide a basis for pressure adjustment. Finally, the pressure of the medium inside the buffer mechanism is adjusted to the target pressure value so that the buffer mechanism can adapt to the current driving status.

[0036] This method involves real-time monitoring of vehicle speed and dynamic pressure adjustment to match the pressure of the buffer mechanism with the collision energy corresponding to the current vehicle speed. When the vehicle is traveling at low speeds, the corresponding collision energy is smaller, resulting in a lower adjusted pressure and moderate rigidity of the buffer mechanism, effectively buffering the impact force. When the vehicle is traveling at high speeds, the corresponding collision energy is larger, requiring a higher adjusted pressure, allowing the buffer mechanism to absorb more collision energy. Through dynamic adjustment in conjunction with the buffer mechanism's sealed cavity and filling medium, pressure regulation alters the stress state of the medium, thereby adjusting the energy absorption capacity of the buffer mechanism. This ensures effective pedestrian protection under different driving conditions while reducing damage to the buffer mechanism itself and front-end vehicle components, thus lowering maintenance costs.

[0037] When determining the target pressure value, if the vehicle speed crosses a speed range threshold, pressure adjustment is only triggered after the vehicle speed has remained within the new range for a predetermined time.

[0038] In actual driving, vehicles may experience frequent speed fluctuations. For example, in congested urban areas, vehicle speeds may alternate between the speed range threshold and the speed range threshold. If pressure regulation is triggered immediately in such situations, it will cause frequent changes in the medium pressure of the buffer mechanism. This not only increases the wear and tear on the medium regulation solenoid valve but may also cause the buffer mechanism to operate in an unstable state. By setting a judgment logic that allows for a predetermined duration, pressure regulation is only performed after the vehicle speed has remained stable within a new speed range for a certain period, confirming that the vehicle has entered the driving state corresponding to that speed range. This reduces ineffective adjustment actions, extends the service life of the buffer mechanism and related components, and ensures the accuracy of pressure regulation, matching the state of the buffer mechanism with the actual driving state of the vehicle.

[0039] The mapping relationship between the speed range and the pressure value is constructed in the following way: dividing the speed range into multiple speed ranges; for each speed range, obtaining the average collision energy through collision simulation; and calculating the corresponding pressure value based on the average collision energy.

[0040] Dividing speed ranges makes pressure adjustment more targeted, avoiding the problem that a single pressure value cannot adapt to different driving conditions. Obtaining average collision energy through collision simulation ensures the accuracy of energy data and avoids the situation where theoretical calculations and actual collisions deviate from each other. Based on energy calculation, the pressure value can be accurately matched with the collision energy. For example, if the average collision energy in a certain speed range is small, the calculated pressure value is low, and the rigidity of the buffer mechanism is moderate, which can buffer the collision without increasing the damage due to excessive rigidity.

[0041] The specific steps are as follows: The S100 collects vehicle speed in real time through the vehicle's built-in Hall effect speed sensor. The S200 transmits the collected vehicle speed signal to the Electronic Control Unit (ECU). The ECU pre-stores a mapping relationship between three speed ranges and their corresponding pressure values. When the vehicle speed enters a certain range, the ECU immediately sends a control signal to the medium adjustment solenoid valve of the buffer mechanism, adjusting the pressure of the medium inside the buffer mechanism to the calculated value for the corresponding range. The process of establishing the speed-pressure adaptation mapping relationship includes: S210 divides vehicle speed ranges into three intervals: low speed (V≤30km / h), corresponding to urban congestion, residential roads, etc.; medium speed (30km / h<V≤60km / h), corresponding to urban main roads, suburban ordinary roads, etc.; and high speed (V>60km / h), corresponding to expressways, suburban expressways, etc.

[0042] The S220 acquires the collision energy corresponding to each speed segment. For the target vehicle model, CAE collision simulation software is used to simulate pedestrian leg collision scenarios at the three speed segments mentioned above. During simulation, parameters such as pedestrian height and collision angle are kept within national standard testing conditions. Five typical speed values ​​are selected for each speed segment for multiple collision simulations; for example, 10km / h, 20km / h, and 30km / h for the low-speed segment; 35km / h, 45km / h, and 55km / h for the medium-speed segment; and 65km / h, 75km / h, and 85km / h for the high-speed segment. The average collision energy E within each speed segment is calculated. For vehicle models with specific scenario requirements, such as commercial vehicles needing to cover low-speed, frequent start-stop scenarios, a speed sub-range for this scenario can be added, such as V≤15km / h, and corresponding collision energy tests can be supplemented to ensure that energy data covers all usage scenarios of the vehicle model.

[0043] S230 calculates the internal pressure of the buffer mechanism corresponding to each speed range. The pressure calculation formula is P=E / (S×L×η). For different speed ranges, the corresponding collision energy value is substituted, where E is the collision energy, S is the cross-sectional area of ​​the cavity, L is the maximum stroke of the sliding sleeve, and η is the energy absorption efficiency, which is 0.7-0.85 for air medium and 0.8-0.9 for liquid medium.

[0044] To avoid frequent pressure adjustments caused by frequent fluctuations in vehicle speed, the S300 incorporates a vehicle speed hysteresis detection logic in the ECU. For example, when the vehicle speed transitions from a low speed range to a medium speed range, it must maintain a speed greater than 30 km / h for 2 seconds before pressure adjustment is triggered, thus preventing frequent adjustments from causing wear and tear on the mechanism.

[0045] While the specific embodiments of the present invention have been described above, they are not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A leg bumper beam, located at the front bumper beam position of a vehicle, characterized in that, The leg impact beam includes a buffer mechanism and the leg beam body; The buffer mechanism includes a cylinder and a sliding sleeve. The sliding sleeve is fitted onto the outside of the cylinder. The cylinder has a sealed cavity. The leg beam body is installed at the front end of the sliding sleeve. A front bumper grille is installed at the front end of the leg beam body. When the vehicle is in motion, the sealed cavity is pressurized, the sliding sleeve moves forward relative to the cylinder, and the leg beam body protrudes forward from the front bumper beam; when the vehicle is stationary, the sliding sleeve moves backward relative to the cylinder, and the front bumper grille is flush with the front bumper beam.

2. The leg impact beam as described in claim 1, characterized in that, The cylinder block has a rear end plate at its rear end, which can be detachably installed on the front end structure of the vehicle body.

3. The leg impact beam as described in claim 1, characterized in that, The front end of the sliding sleeve has a front end cover, which is detachably mounted on the rear side of the leg beam body.

4. The leg impact beam as described in claim 3, characterized in that, The rear side of the leg beam body is fixed with a rivet nut or a projection weld nut, and the front end cover is installed in the rivet nut or projection weld nut by screws.

5. The leg impact beam as described in claim 1, characterized in that, The leg beam body is made of structural steel, steel plate, or composite material.

6. The leg impact beam as described in claim 1, characterized in that, The cylinder is filled with a liquid or gas.

7. The leg impact beam as described in claim 1, characterized in that, The leg beam body is connected to the front bumper grille by bolts or clips.

8. A control method for a leg impact beam as described in any one of claims 1-7, characterized in that, include: Real-time vehicle speed data collection; The target pressure value of the medium inside the buffer mechanism is determined based on the pre-stored mapping relationship between the speed range and the pressure value. Adjust the pressure of the medium inside the buffer mechanism to the target pressure value.

9. The control method as described in claim 8, characterized in that, When determining the target pressure value, if the vehicle speed crosses a speed range threshold, pressure adjustment is only triggered after the vehicle speed has remained within the new range for a predetermined time.

10. The control method as described in claim 8, characterized in that, The mapping relationship between the speed range and the pressure value is constructed in the following way: Divide into multiple speed ranges; For each velocity range, the average collision energy is obtained through collision simulation; The pressure value is calculated based on the average collision energy.

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