Energy absorber structure and design method

Abstract

The present application relates to an energy absorber structure and design method, which includes: an energy absorber body, the energy absorber body is used to be arranged inside the automobile insulation pad, and is located between the structural weak point of the engine hood and the hard point of the cabin, the energy absorber body includes: a support seat, multiple limiting elements and an elastic element, the support seat is used to be fixed inside the automobile insulation pad; multiple limiting elements are arranged circumferentially around the support seat, and one end is fixed inside the support seat; the elastic element is clamped on the support seat; the energy absorber body is configured as follows: when the energy absorber body is in the initial state, the limiting element abuts the bottom end of the elastic element to limit the downward movement of the elastic element; when the energy absorber body is under pressure, the limiting element contracts to move the other end of the limiting element toward the inside of the support seat, and the elastic element moves downward. In the present invention, the parts cost of the energy absorber body is low, and the after-sales maintenance cost is also low. After a collision occurs, the hinge and other parts will not be damaged, and the energy absorber body itself can also be reused.

Description

Technical Field

[0001] The present application relates to the automotive field, and in particular to an energy absorber structure and design method. Background Art

[0002] When a car collides with a pedestrian, inertia forces the pedestrian toward the front of the car, with their head typically striking the hood first. To minimize head injuries, the potential for pedestrian head impacts must be considered and analyzed during the initial design of the hood and lower components. Currently, limits on pedestrian head impact damage are incorporated into mandatory national regulations. These increasingly stringent regulations are forcing OEMs to find every possible way to minimize these risks.

[0003] The design of pedestrian head protection generally requires that the cabin hard point under the hood be greater than 70mm away from the outer shape of the hood, that is, to ensure sufficient head impact cushioning distance. However, the layout and design of many places cannot meet the above requirements, resulting in relatively large head impact damage values ​​in the corresponding parts. The existing technology increases the cushioning distance by raising the hood or generating airbags on the upper part of the hood after a collision. This type of solution has the following problems: the cost of technical parts is high, such as active hood hinges, which increase the cost per vehicle by about. Pedestrian airbags, which increase the cost per vehicle by about; after the head impact protection is triggered, the device will damage the hood hinges, airbags and other structures, and the corresponding parts need to be replaced during maintenance, which is costly; due to insufficient sensor recognition accuracy, it can cause false triggering during actual driving, causing customer complaints. Or the recognition response time is long, the triggering is delayed, affecting the effectiveness of head impact protection; the additional mechanism requires a separate layout space, which is difficult to design and has a long cycle. Summary of the Invention

[0004] The present application provides an energy absorber structure and design method, which can solve the problems in related technologies that energy absorber structures cannot be reused, require separate layout space, and have the probability of false triggering or triggering delay.

[0005] In a first aspect, an embodiment of the present application provides an energy absorber structure, comprising:

[0006] The energy absorber body is used to be arranged inside the automobile insulation pad and is located between the structural weak point of the engine hood and the hard point of the cabin. The energy absorber body includes: a support seat, multiple limiting elements and an elastic element. The support seat is used to be fixed inside the automobile insulation pad; multiple limiting elements are arranged circumferentially around the support seat, and one end is fixed inside the support seat; the elastic element is clamped on the support seat; the energy absorber body is configured as follows: when the energy absorber body is in the initial state, the limiting element abuts against the bottom end of the elastic element to limit the downward movement of the elastic element; when the energy absorber body is under pressure, the limiting element contracts to make the other end of the limiting element move toward the inside of the support seat, and the elastic element moves downward.

[0007] In combination with the first aspect, in one embodiment, the energy absorber body further includes: a pre-compression bag, the support seat, the elastic element and the plurality of limiting elements are all arranged inside the pre-compression bag, and the pre-compression bag is used to be arranged inside the automobile insulation pad.

[0008] In combination with the first aspect, in one embodiment, the top and bottom ends of the pre-compression bag are made of hard material, and the side surfaces of the pre-compression bag are made of flexible material; the support seat abuts the bottom end of the pre-compression bag, and the elastic element abuts the top end of the pre-compression bag.

[0009] In combination with the first aspect, in one embodiment, the limiting element includes: a limiting spring and a limiting ball, the support seat is circumferentially provided with a sliding groove, one end of the limiting spring is slidably connected to the inside of the sliding groove, and the other end is fixed to the inner wall of the sliding groove; the limiting ball is fixed to one end of the limiting spring, and when the energy absorber body is in the initial state, the limiting ball resists the bottom end of the elastic element.

[0010] In combination with the first aspect, in one embodiment, the elastic element is an inverted cone, the elastic element is a spring, the horizontal distance between the limiting element and the central axis of the support seat is a first length, half of the inner diameter of the first circle of the small end of the elastic element is less than the first length, and half of the inner diameter of the second circle of the small end of the elastic element is greater than the first length.

[0011] In a second aspect, an embodiment of the present application provides a method for designing an energy absorber structure, which includes:

[0012] Conduct pedestrian collision simulation experiments to obtain collision waveforms;

[0013] Based on the first peak acceleration in the collision waveform and the set head weight, the required specific cushioning force is obtained;

[0014] Design the parameters of the elastic element and the support base so that the elastic element satisfies the requirement that the compression force of the elastic element can be instantly reduced when the compression force of the elastic element is equal to the required specific buffer force;

[0015] Design the limit unit parameters so that when the compression force of the elastic element is equal to the required specific buffer force, the limit unit contracts and the elastic element can move downward instantly;

[0016] The energy absorber structure is determined based on the elastic element parameters, support seat parameters and limit unit parameters.

[0017] In conjunction with the second aspect, in one embodiment, the elastic element is in an inverted cone shape, and the elastic element is a spring;

[0018] The elastic element parameters include the middle diameter of the spring at the small end of the elastic element, the middle diameter of the spring at the large end of the elastic element, the diameter of the spring coil of the elastic element, the effective number of turns of the elastic element, and the shear modulus of the spring material of the elastic element.

[0019] In conjunction with the second aspect, in one embodiment, when the compression force of the elastic element is equal to the required specific buffer force, the compression force of the elastic element can be instantly reduced, and the parameters of the elastic element and the support seat meet the following conditions:

[0020] Two times the difference between half the inner diameter of the first circle of the small end of the elastic element and the radius of the support seat is less than the distance between the end of the limiting unit of the energy absorber body and the surface of the support seat in the initial state;

[0021] Half of the inner diameter of the second circle of the small end of the elastic element is greater than the sum of the distance between the end of the limiting unit and the surface of the support seat in the initial state of the energy absorber structure and the radius of the support seat.

[0022] In conjunction with the second aspect, in one embodiment, when the compression force of the elastic element is equal to the required specific buffering force, the limiting unit contracts, and the elastic element can move downward instantaneously, the limiting unit parameters satisfy:

[0023] The product of the tangent of the angle between the contact tangent of the small end of the elastic element and the limiting unit and the axis of the limiting unit and the required specific buffer force is equal to the compression force when the limiting unit is compressed by the elastic element component until the elastic element slides off.

[0024] In conjunction with the second aspect, in one embodiment, after determining the energy absorber structure based on the elastic element parameters, the support seat parameters, and the limit unit parameters, the method further includes:

[0025] A pedestrian collision simulation experiment is conducted using the energy absorber structure to determine whether the collision waveform obtained at this time is an ideal waveform;

[0026] If yes, the energy absorber structure design is completed;

[0027] Otherwise, the elastic element parameters, the support seat parameters, and the limit unit parameters are adjusted until the collision waveform obtained by the pedestrian collision simulation experiment is an ideal waveform.

[0028] The beneficial effects of the technical solutions provided in the embodiments of the present application include:

[0029] The embodiment of the present application provides an energy absorber structure and design method. The parts cost of the energy absorber body is low, and the after-sales maintenance cost is also low. After a collision, the hinges and other parts will not be damaged, and the energy absorber body itself can be reused; the energy absorber body is preset inside the engine hood insulation pad. When a collision occurs, the sensor-BCM-trigger detonation process is not required. There is no problem of false triggering and triggering delay, and the protection of the head is more accurate and sufficient; the energy absorber body is arranged inside the insulation pad of the engine hood, and does not require a separate arrangement space. It can be arranged at any position inside the insulation pad as needed, with flexible arrangement and simple design. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0031] Figure 1 An exploded view of the energy absorber body provided in an embodiment of the present application;

[0032] Figure 2 A schematic diagram of the installation position of the energy absorber body provided in an embodiment of the present application;

[0033] Figure 3 A schematic diagram of the installation position of the energy absorber body provided in an embodiment of the present application;

[0034] Figure 4 A schematic diagram of the energy absorber body provided in an embodiment of the present application;

[0035] Figure 5 for Figure 4 The local enlarged schematic diagram of point I in the middle;

[0036] Figure 6 A schematic diagram of the waveform of the gold ejector pin provided in an embodiment of the present application;

[0037] Figure 7 A schematic diagram of a hump waveform provided in an embodiment of the present application.

[0038] In the figure: 1. Energy absorber body; 11. Pre-compression bag; 12. Elastic element; 13. Limiting ball; 14. Limiting spring; 15. Support seat; 2. Engine hood; 3. Thermal insulation pad; 4. Cabin hard point; 5. Head-shaped simulated collision device. DETAILED DESCRIPTION

[0039] In order to enable those skilled in the art to better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0040] See also Figures 1 to 7 The embodiments of the present application provide an energy absorber structure and design method, which can solve the problems in related technologies that the energy absorbing structure cannot be reused, requires a separate layout space, and has the probability of false triggering or triggering delay.

[0041] In the first aspect, an embodiment of the present application provides an energy absorber structure, which includes: an energy absorber body 1, the energy absorber body 1 is used to be arranged inside the automobile thermal insulation pad 3, and is located between the structural weak point of the engine hood 2 and the cabin hard point 4, the energy absorber body 1 includes: a support seat 15, a plurality of limiting elements and an elastic element 12, the support seat 15 is used to be fixed inside the automobile thermal insulation pad 3; a plurality of limiting elements are circumferentially arranged around the support seat 15, and one end is fixed inside the support seat 15; the elastic element 12 is clamped on the support seat 15; the energy absorber body 1 is configured as follows: when the energy absorber body 1 is in the initial state, the limiting element abuts against the bottom end of the elastic element 12 to limit the downward movement of the elastic element 12; when the energy absorber body 1 is under pressure, the limiting element contracts to make the other end of the limiting element move toward the inside of the support seat 15, and the elastic element 12 moves downward.

[0042] In the present application, the parts cost of the energy absorber body 1 is low, and the after-sales maintenance cost is also low. After a collision occurs, the hinges and other parts will not be damaged, and the energy absorber body 1 itself can also be reused; the energy absorber body 1 is preset inside the thermal insulation pad 3 of the engine hood 2. When a collision occurs, the sensor-BCM-trigger detonation process is not required. There is no problem of false triggering and triggering delay, and the protection of the head is more accurate and sufficient; the energy absorber body 1 is arranged inside the thermal insulation pad 3 of the engine hood 2, and does not require a separate arrangement space. It can be arranged at any position inside the thermal insulation pad 3 as needed, with flexible arrangement and simple design.

[0043] During the CAE simulation analysis phase of vehicle design, the animation and acceleration-displacement curve of a pedestrian's head impacting the engine hood 2 can be calculated. Figure 4 、 Figure 5 According to the curve chart, it can be judged whether the part needs to add an energy absorber structure and the force value required by the energy absorber structure. This part is generally where the engine hood 2 structure is relatively weak, which is called the structural weakness of the engine hood 2 in this embodiment. The buffering provided at the structural weakness of the engine hood 2 is insufficient, and the lower cabin hard point 4 is close to the engine hood 2.

[0044] After determining the layout position, a space is reserved inside the car heat insulation pad 3 for placing the energy absorber structure. The core structure of the energy absorber structure is the elastic element 12, which can increase the buffering force for head impact. The buffering force output by the elastic element 12 needs to be designed, because if the buffering force output by the elastic element 12 is too small, the head will still have a high speed at the moment of hitting the cabin hard point 4, and the speed will drop rapidly after hitting the cabin hard point 4, that is, the acceleration during the collision with the cabin hard point 4 is too large, and the damage value is particularly high. On the contrary, if the buffering force output by the elastic element 12 is too large, the head will be subjected to excessive buffering force before hitting the cabin hard point 4, and the damage value will also be very high.

[0045] The specific design method of the energy absorber structure is described in the energy absorber structure design method below and will not be explained in detail here.

[0046] On the basis of the above embodiments, in this embodiment, the limiting element includes: a limiting spring 14 and a limiting ball 13, the support seat 15 is circumferentially provided with a sliding groove, one end of the limiting spring 14 is slidably connected to the inside of the sliding groove, and the other end is fixed to the inner wall of the sliding groove; the limiting ball 13 is fixed to one end of the limiting spring 14, and when the energy absorber body 1 is in the initial state, the limiting ball 13 presses against the bottom end of the elastic element 12.

[0047] Specifically, the support base 15 is configured as a columnar structure, with horizontally spaced slots defined around the support base 15. The slots are positioned horizontally, and the limit spring 14 is mounted within the slots. The limit spring 14 is secured to the slots on the side closest to the center of the support base 15 and slidably connected to the slots on the side away from the center of the support base 15. The limit ball 13 is secured to the side of the limit spring 14 away from the center of the support base 15. When pressure is applied to the limit ball 13, it moves into the slots, compressing the limit spring 14. After the limit ball 13 moves into the slots, the lower end of the elastic element 12 can slide off the limit ball 13.

[0048] Based on the above embodiments, in this embodiment, the elastic element 12 is an inverted cone, the elastic element 12 is a spring, the horizontal distance between the limiting element and the central axis of the support seat 15 is a first length, half of the inner diameter of the first circle of the small end of the elastic element 12 is less than the first length, and half of the inner diameter of the second circle of the small end of the elastic element 12 is greater than the first length.

[0049] Specifically, the ideal collision waveform is that after the first collision peak reaches the ideal value, it needs to drop as quickly as possible and cannot continue to stay at the peak. In other words, after the cushioning force of the head hitting the engine hood 2 reaches the target value, the cushioning force needs to be reduced as quickly as possible. To achieve this ideal state, the elastic element 12 of the present application is designed as an inverted cone, and its taper has been carefully calculated and designed so that when the first circle of the small end of the inverted cone elastic element 12 slides off the limiting ball 13, the inner diameter of the first circle of the small end of the elastic element 12 is larger than the position where the limiting ball 13 is pushed to the outermost edge by the limiting spring 14.

[0050] Here, the horizontal distance between the limiting element and the central axis of the support seat 15 is set to a first length, and half of the inner diameter of the first circle at the small end of the elastic element 12 is smaller than the first length, and half of the inner diameter of the second circle at the small end of the elastic element 12 is larger than the first length. This is so that in the initial state of the energy absorber body 1, the limiting ball 13 abuts against the first circle at the small end of the elastic element 12. When the elastic element 12 is pressed down, the compression force of the first circle at the small end of the elastic element 12 can compress the limiting spring 14 through the limiting ball 13, causing the limiting ball 13 to move into the chute. After the limiting ball 13 moves into the chute, the second circle at the small end of the elastic element 12 to the large end of the elastic element 12 can slide off the limiting ball 13, so that the limiting ball 13 no longer limits the elastic element 12, thereby eliminating the force of the elastic element 12.

[0051] Based on the above embodiments, in this embodiment, the energy absorber body 1 also includes: a pre-compression bag 11, a support seat 15, an elastic element 12 and multiple limiting elements are all arranged inside the pre-compression bag 11, and the pre-compression bag 11 is used to be arranged inside the automobile insulation pad 3.

[0052] Specifically, the top and bottom of the pre-compression bag 11 are made of hard material, and the side of the pre-compression bag 11 is made of flexible material; the support seat 15 abuts the bottom of the pre-compression bag 11, and the elastic element 12 abuts the top of the pre-compression bag 11.

[0053] The elastic element 12, the limiting element, and the support seat 15 are wrapped in a cylindrical cloth bag with plastic sheets at the upper and lower ends. This allows the elastic element 12, in its initial pre-compressed state, to press against the plastic sheets above and below the cloth bag, thereby securing the energy absorber body 1 and facilitating its assembly into the thermal pad 3. Furthermore, once the energy absorber body 1 is inserted into the thermal pad 3, the elastic element 12, constrained by the cloth bag, will not exert force on the thermal pad 3, thus preventing deformation of the upper and lower covering layers of the thermal pad 3. The sides of the cloth bag are covered with soft cloth, so that when a pedestrian's head initially impacts the hood 2 and the energy absorber body 1, the energy absorber body 1 can be compressed smoothly without being hindered by the soft cloth on the sides.

[0054] In a second aspect, an embodiment of the present application provides a method for designing an energy absorber structure, which includes:

[0055] 101: Conduct a pedestrian collision simulation experiment and obtain a collision waveform diagram;

[0056] 102: Obtain the required specific cushioning force based on the first peak acceleration in the collision waveform and the set head weight;

[0057] 103: Design the parameters of the elastic element 12 and the support base 15 so that the elastic element 12 satisfies the requirement that the compression force of the elastic element 12 can be instantly reduced when the compression force of the elastic element 12 is equal to the required specific buffering force;

[0058] 104: Design the parameters of the limit unit so that when the compression force of the elastic element 12 is equal to the required specific buffer force, the limit unit contracts and the elastic element 12 can move downward instantly;

[0059] 105: Determine the energy absorber structure based on the parameters of the elastic element 12, the parameters of the support seat 15 and the parameters of the limit unit.

[0060] In this application, the specific structure of the energy absorber structure is as described above.

[0061] When designing the energy absorber structure, we first followed the existing vehicle development process. After the initial data was completed, pedestrian collision simulation experiments were carried out. The head-shaped impactor 5 was used for the experiment. The acceleration-displacement diagram (also known as the collision waveform diagram) of each impact point in the adult and child head collision area was analyzed. Figure 3 As shown, the X direction in the figure is the impact direction.

[0062] Referring to research results related to pedestrian protection, the ideal collision waveform is when the first peak acceleration reaches 1.2, corresponding to the collision model, which is the stage of hood 2 crushing and buffering energy absorption, indicating that the hood 2 has sufficient plastic deformation and buffering energy absorption effect. When it hits the cabin hard point 4 below the hood 2, the acceleration rises again, generating a second peak. After the first peak is fully buffered by the hood 2, the second peak acceleration can only rise to about 0.8, and then decreases. Subsequent peaks gradually decrease, with the decrease amount being about 1 / 3. This waveform is called a golden needle waveform, see Figure 6 As shown, the damage to the head is relatively small.

[0063] Another typical waveform is called a hump waveform: the first peak acceleration is relatively small (usually only up to 0.8), indicating that the elastic deformation of the hood 2 is insufficient and the energy absorption of the head is weak. When it hits the cabin hard point 4 below the hood 2, a second peak is generated. Because the hood 2 does not absorb enough energy at the beginning, the head still has a high collision velocity at this time, causing the second peak acceleration to rise to 1.2 or even higher. This waveform is called a hump waveform, see Figure 7 , which causes greater damage to the head.

[0064] The purpose of designing the energy absorber structure in this application is to convert the hump waveform into a gold thimble waveform.

[0065] After clarifying the above goals, we can carry out quantitative calculations on the hump waveform and derive the parameters of the energy absorber structure:

[0066] Based on the first peak acceleration in the collision waveform and the set head weight, the specific cushioning force F1 required for this part is derived using the formula:

[0067] F1=(1.2-a)*m, where a is the first peak acceleration and m is the head weight (4.5 kg for adults and 3.5 kg for children). This specific buffering force F1 is the maximum force value that the energy absorber body 1 needs to reach.

[0068] In the present application, the elastic element 12 is an inverted cone, the elastic element 12 is a spring, and the parameters of the elastic element 12 include the spring middle diameter at the small end of the elastic element 12, the spring middle diameter at the large end of the elastic element 12, the spring coil diameter of the elastic element 12, the effective number of turns of the elastic element 12, and the shear modulus of the spring material of the elastic element 12.

[0069] Then, the parameters of the elastic element 12 and the support seat 15 are designed so that the compression force of the elastic element 12 can be instantly reduced when the compression force of the elastic element 12 is equal to the required specific buffering force; the parameters of the limit unit are designed so that the limit unit can contract and the elastic element 12 can instantly move downward when the compression force of the elastic element 12 is equal to the required specific buffering force.

[0070] The compression force F(x) of the conical spring is equal to x×K, where x is the spring compression displacement and K is the spring elastic coefficient. In this application, the spring elastic coefficient K of the elastic element 12 needs to be designed.

[0071] The spring coefficient K of the elastic element 12 is calculated as follows:

[0072]

[0073] Among them, R1 is half of the middle diameter of the spring at the small end of the elastic element 12, R2 is half of the middle diameter of the spring at the large end of the elastic element 12, d is the diameter of the spring coil of the elastic element 12, n is the effective number of turns of the elastic element 12, and G is the shear modulus of the spring material of the elastic element 12. Therefore, it is necessary to design the middle diameter of the spring at the small end of the elastic element 12, the middle diameter of the spring at the large end of the elastic element 12, the diameter of the spring coil of the elastic element 12, the effective number of turns of the elastic element 12, and the shear modulus of the spring material of the elastic element 12.

[0074] In order to ensure that the conical spring compression force F(x) can be instantly reduced when it reaches the required specific buffer force F1, the limiting ball 13 must be able to limit the first circle of the small end of the elastic element 12 but not limit other circles.

[0075] In order to achieve this goal, the dimensional parameters of the elastic element 12 also need to meet the following requirements:

[0076] When the compression force of the elastic element 12 is equal to the required specific buffering force and the compression force of the elastic element 12 can be instantly reduced, the parameters of the elastic element 12 and the parameters of the support seat 15 satisfy: twice the difference between half of the inner diameter of the first circle of the small end of the elastic element 12 and the radius of the support seat 15 is less than the distance length between the end of the limit unit of the energy absorber body 1 and the surface of the support seat 15 in the initial state; half of the inner diameter of the second circle of the small end of the elastic element 12 is greater than the sum of the distance length between the end of the limit unit of the energy absorber body 1 and the surface of the support seat 15 in the initial state and the radius of the support seat 15.

[0077] That is, it needs to meet:

[0078] (K1-N)*2<M;L>M+N. Where K1=R1-d / 2, (L-K1)*n=R2-R1, K1 is half of the inner diameter of the first circle of the small end of the elastic element 12, L is half of the inner diameter of the second circle of the small end of the elastic element 12, N is the radius of the support seat 15, and M is the distance that the limiting ball 13 of the energy absorber body 1 protrudes from the support seat 15 in the initial state. Figure 5 .

[0079] When designing the limit spring 14, calculate the force F(y) transmitted from F(x) to the limit spring 14 through the limit ball 13: F(y) = F(x)*tanα, where α is the angle between the contact tangent of the small end of the conical spring and the limit ball 13 and the axis of the limit spring 14. Figure 5 .

[0080] In order to ensure that when the compression force F(x) of the elastic element 12 reaches the required F1 value, the elastic element 12 can instantly slide off the limiting ball 13, that is, when the compression force of the elastic element 12 is equal to the required specific buffer force, the limiting unit contracts and the elastic element 12 can instantly move downward, the limiting unit parameters must also meet the following requirements:

[0081] The product of the tangent of the angle between the small end of the elastic element 12 and the contact tangent of the limit unit and the axis of the limit unit and the required specific buffering force is equal to the compression force of the limit unit compressed by the component force of the elastic element 12 to the point where the elastic element 12 slides off: F1*tanα=F2, where F2 is the force of the limit ball 13 compressed by the component force of the elastic element 12 to the point where the elastic element 12 slides off, F2=K2*(X0+ΔX), where X0 is the pre-compression amount of the limit spring 14, K2 is the elastic coefficient of the limit spring 14, ΔX=M+N-K1, and the dimensional parameters of the limit spring 14 can be designed accordingly.

[0082] Based on the above embodiment, in this embodiment, after determining the energy absorber structure based on the parameters of the elastic element 12, the parameters of the support seat 15, and the parameters of the limiting unit, the method further includes:

[0083] A pedestrian collision simulation experiment is conducted using the energy absorber structure to determine whether the collision waveform obtained at this time is an ideal waveform;

[0084] If yes, the energy absorber structure design is completed;

[0085] Otherwise, the parameters of the elastic element 12 , the supporting base 15 and the limiting unit are adjusted until the collision waveform obtained by the pedestrian collision simulation experiment is an ideal waveform.

[0086] Specifically, after the above steps, the parameters of the energy absorber body 1 required for the structural weakness of the engine hood 2 to be optimized can be derived and designed. After the design is completed, the model of the energy absorber body 1 is input into the computer again to verify whether the waveform of the structural weakness of the engine hood 2 reaches the ideal waveform. If it does not reach the ideal waveform, the parameters of the elastic element 12, the parameters of the support seat 15 and the parameters of the limit unit are adjusted until the collision waveform diagram obtained from the pedestrian collision simulation experiment is the ideal waveform diagram. In the actual vehicle test stage, the parameters of the energy absorber body 1 can still be adjusted according to the curve verified by the actual vehicle to further optimize the head collision curve and reduce the pedestrian head injury value.

[0087] In summary, the parts cost of this application is low, and the after-sales maintenance cost is also low: hinges and other parts will not be damaged after a collision, and the energy absorber body 1 itself can be reused. The energy absorber body 1 of this application is preset inside the thermal insulation pad 3 of the engine hood 2. When a collision occurs, there is no need for the sensor-BCM-trigger detonation process, and there is no problem of false triggering and triggering delay. The protection of the head is more accurate and sufficient; the energy absorber body 1 of this application is arranged inside the thermal insulation pad 3 of the engine hood 2, and does not require a separate arrangement space. It can be arranged at any position inside the thermal insulation pad 3 as needed, with flexible arrangement and simple design; this application can be optimized point-to-point according to the CAE analysis curve: the energy absorber body 1 can be arranged according to needs, and the energy absorption value and parameters of the energy absorber body 1 can be accurately designed according to the CAE curve to improve the optimization effect; in the actual vehicle stage, the parameters of the energy absorber body 1 can also be modified according to the actual vehicle collision results to further improve the pedestrian protection effect.

[0088] In the description of this application, it should be noted that the terms "upper" and "lower" and the like indicate orientations or positional relationships based on the orientations or positional relationships 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. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be internal communication between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0089] It should be noted that, in this application, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element.

[0090] The foregoing is merely a list of specific embodiments of the present application, intended to enable those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the broadest scope consistent with the principles and novel features of the present application.

Claims

1. An energy absorber structure, characterized in that: It includes: An energy absorber body (1) is used to be arranged inside a car heat insulation pad (3) and is located between a structural weak point of an engine hood (2) and a hard point (4) of an engine cabin. The energy absorber body (1) comprises: - a support seat (15), the support seat (15) being used to be fixed inside the automobile thermal insulation pad (3); - a plurality of limiting elements, wherein the plurality of limiting elements are circumferentially arranged around the support seat (15) and one end of the limiting elements is fixed inside the support seat (15); - an elastic element (12), the elastic element (12) being snap-connected to the support seat (15); The energy absorber body (1) is configured as follows: when the energy absorber body (1) is in an initial state, the limiting element abuts against the bottom end of the elastic element (12) to limit the downward movement of the elastic element (12); when the energy absorber body (1) is in a compressed state, the limiting element contracts to allow the other end of the limiting element to move toward the inside of the support seat (15), and the elastic element (12) moves downward.

2. The energy absorber structure according to claim 1, wherein: The energy absorber body (1) further comprises: A pre-compression bag (11), wherein the support seat (15), the elastic element (12) and the plurality of limiting elements are all arranged inside the pre-compression bag (11), and the pre-compression bag (11) is used to be arranged inside the automobile thermal insulation pad (3).

3. The energy absorber structure according to claim 2, wherein: The top and bottom ends of the pre-compression bag (11) are made of hard material, and the side surfaces of the pre-compression bag (11) are made of flexible material; The support seat (15) abuts against the bottom end of the pre-compression bag (11), and the elastic element (12) abuts against the top end of the pre-compression bag (11).

4. The energy absorber structure according to claim 1, characterized in that: The limiting element includes: A limit spring (14), wherein the support seat (15) is provided with a sliding groove in the circumferential direction, one end of the limit spring (14) is slidably connected to the inside of the sliding groove, and the other end is fixed to the inner wall of the sliding groove; A limiting ball (13) is fixed to one end of a limiting spring (14); when the energy absorber body (1) is in an initial state, the limiting ball (13) abuts against the bottom end of the elastic element (12).

5. The energy absorber structure according to claim 1, wherein: The elastic element (12) is in an inverted cone shape, the elastic element (12) is a spring, the horizontal distance between the limiting element and the central axis of the support seat (15) is a first length, half of the inner diameter of the first circle of the small end of the elastic element (12) is smaller than the first length, and half of the inner diameter of the second circle of the small end of the elastic element (12) is larger than the first length.

6. A method for designing an energy absorber structure, which is used to design the energy absorber structure according to any one of claims 1 to 5, characterized in that: It includes: Conduct pedestrian collision simulation experiments to obtain collision waveforms; Based on the first peak acceleration in the collision waveform and the set head weight, the required specific cushioning force is obtained; Designing parameters of the elastic element (12) and the support seat (15) so that the elastic element (12) satisfies the requirement that the compression force of the elastic element (12) can be instantly reduced when the compression force of the elastic element (12) is equal to the required specific buffering force; Designing the parameters of the limit unit so that the limit unit satisfies the requirement that when the compression force of the elastic element (12) is equal to the required specific buffer force, the limit unit contracts and the elastic element (12) can move downward instantaneously; The energy absorber structure is determined based on the parameters of the elastic element (12), the parameters of the support seat (15), and the parameters of the limiting unit.

7. The energy absorber structure design method according to claim 6, characterized in that: The elastic element (12) is in an inverted cone shape, and the elastic element (12) is a spring; The parameters of the elastic element (12) include the middle diameter of the spring at the small end of the elastic element (12), the middle diameter of the spring at the large end of the elastic element (12), the diameter of the spring coil of the elastic element (12), the effective number of turns of the elastic element (12), and the shear modulus of the spring material of the elastic element (12).

8. The energy absorber structure design method according to claim 6, characterized in that: When the compression force of the elastic element (12) is equal to the required specific buffer force and the compression force of the elastic element (12) can be instantly reduced, the parameters of the elastic element (12) and the parameters of the support seat (15) satisfy: Twice the difference between half the inner diameter of the first circle of the small end of the elastic element (12) and the radius of the support seat (15) is less than the distance between the end of the limiting unit of the energy absorber structure and the surface of the support seat (15) in the initial state; Half of the inner diameter of the second circle of the small end of the elastic element (12) is greater than the sum of the distance between the end of the limiting unit of the energy absorber structure and the surface of the support seat (15) in the initial state and the radius of the support seat (15).

9. The energy absorber structure design method according to claim 6, characterized in that: When the compression force of the elastic element (12) is equal to the required specific buffer force, the limit unit contracts, and the elastic element (12) can move downward instantaneously, the limit unit parameters satisfy: The product of the tangent of the angle between the contact tangent of the small end of the elastic element (12) and the limiting unit and the axis of the limiting unit and the required specific buffering force is equal to the compression force of the limiting unit being compressed by the component force of the elastic element (12) until the elastic element (12) slides off.

10. The energy absorber structure design method according to claim 6, characterized in that: After determining the energy absorber structure based on the elastic element (12) parameters, the support seat (15) parameters, and the limit unit parameters, the method further comprises: A pedestrian collision simulation experiment is conducted using the energy absorber structure to determine whether the collision waveform obtained at this time is an ideal waveform; If yes, then complete the energy absorber structure design; Otherwise, the parameters of the elastic element (12), the supporting seat (15) and the limiting unit are adjusted until the collision waveform obtained by the pedestrian collision simulation experiment is an ideal waveform.

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