A three-dimensional printed buffer structure for helmets

Abstract

A three-dimensional printed buffer structure for helmets includes a first buffer layer. The first buffer layer includes an outer surface portion, an inner surface portion, and a plurality of supports. The outer surface portion includes a plurality of first rods arranged to intersect and form a grid, with the first rods defining an outer contour near a helmet shell. The inner surface portion includes a plurality of second rods that extend continuously and are spaced apart, remaining adjacent to one another without intersecting, with the second rods defining an inner contour close to a user. The supports are arranged between the outer surface portion and the inner surface portion, with each of the supports having a first end and a second end, in which the first end and the second end of any one of the supports are respectively connected to any one of the first rods and any one of the second rods. The first rods, the second rods, and the supports are integrally formed by three-dimensional printing.

Description

A 3D printed cushioning structure for helmets The present disclosure relates to a three-dimensional printed structure, and more particularly to a three-dimensional printed cushioning structure for use in helmets. Common helmet designs today usually focus on absorbing vertical forces, but the problem of how to reduce lateral displacement or rotation of the helmet caused by lateral forces has not been fully solved. In actual use, when the helmet is subjected to lateral forces, it is easy for the helmet to cause lateral displacement or rotation between the helmet and the user's head due to insufficient design of the internal buffer structure. This lateral displacement or rotation will not only reduce the stability of the helmet, but may also cause local stress concentration in certain areas, increasing the risk of injury to the user. In addition, the buffer structure design in existing helmets is also relatively limited in its ability to disperse stress, resulting in the problem of local stress concentration. Therefore, how to effectively improve the stability of the helmet under lateral forces while taking into account the stress dispersion ability of the helmet is a topic that technical personnel in this field are actively researching. According to some embodiments of the present disclosure, a three-dimensional printed buffer structure for a helmet includes a first buffer layer. The first buffer layer includes an outer surface portion, an inner surface portion, and a plurality of support members. The outer surface portion includes a plurality of first rods, wherein the first rods are arranged to form a grid by crossing each other, and define an outer contour close to the outer shell of the helmet. The inner surface portion includes a plurality of second rods, wherein the second rods extend continuously and are spaced apart from each other and adjacent to each other without intersecting, and define an inner contour close to the user. The support members are arranged between the outer surface portion and the inner surface portion, and each support member has a first end and a second end, wherein the first end and the second end of any support member are respectively connected to any first rod and any second rod. The first rod, the second rod, and the support member are integrated by three-dimensional printing. In some embodiments of the present disclosure, any supporting member is a straight column member. In some embodiments of the present disclosure, a first connection angle between any support member and the connected first rod is 45 degrees to 135 degrees, and a second connection angle between any support member and the connected second rod is 45 degrees to 135 degrees. In some embodiments of the present disclosure, the first end of any support member is connected to an intersection of the grid. In some embodiments of the present disclosure, any two or more adjacent support members intersect with each other. In some embodiments of the present disclosure, any two or more adjacent support members intersect with each other at any first rod or any second rod. In some embodiments of the present disclosure, the three-dimensional printed cushioning structure further includes a second cushioning layer connected to the outer surface portion and disposed between the outer surface portion and the outer shell of the helmet, and includes a plurality of lattice structure units, each of which has a hollow area. In some embodiments of the present disclosure, the first rod, the second rod, the support member, and the lattice structure unit are integrated into one piece by three-dimensional printing. In some embodiments of the present disclosure, each first rod, each second rod, and each support member each has a plurality of cellular structures. In some embodiments of the present disclosure, there are multiple first hollow areas between the first rods, multiple second hollow areas between the second rods, and multiple third hollow areas between the support members, and the first hollow areas, second hollow areas and third hollow areas are connected. According to the above-mentioned embodiment of the present disclosure, by using a non-filled grid design (first rod) to form the outer surface portion of the first buffer layer, external forces can be dispersed over a wider range, reducing the damage caused by concentrated stress to a single area and effectively reducing the risk of injury. By using continuous rods (second rods) that extend continuously and do not intersect with each other to form the inner surface portion of the first buffer layer, not only can good head fit (compliance) be provided, but in combination with the design of the support member, the friction of the first buffer layer on the head in a specific direction can also be enhanced, thereby limiting the relative displacement between the helmet and the head, thereby limiting the lateral deviation or rotation of the helmet and enhancing the wearing stability of the helmet. In addition, through the deflection of the support member, the horizontal first rod and the second rod can share the vertically applied load, achieving a stress dispersion effect. Overall, through the synergistic effect of the first rod, the second rod and the support member, the present disclosure can improve the overall protective performance and wearing stability of the helmet in a way that is different from "directly absorbing vertical stress." The following diagrams will disclose multiple embodiments of the present disclosure. For the sake of clarity, many practical details will be described together in the following description. However, these practical details should not be used to limit the present disclosure. In addition, for the convenience of readers, the sizes of the elements in the drawings are not drawn according to the actual scale. In addition, relative terms such as "lower" and "upper" may be used in this article to describe the relationship between one element and another element, as shown in the drawings. It should be understood that relative terms are intended to include different orientations of the device in addition to the orientation shown in the figures. In addition, terms such as "first" and "second" mentioned in the specification or patent application are only used to name different elements, or to distinguish different embodiments or scopes, and are not used to limit the upper or lower limit on the number of elements, nor to limit the manufacturing order or setting order of the elements. Please refer to Figure 1, which is a three-dimensional schematic diagram of a three-dimensional printed buffer structure 10 applied to a helmet according to some embodiments of the present disclosure, which is a perspective of observing the internal structure from the bottom opening of the helmet. It should be understood that the term "helmet" herein generally refers to equipment used to protect the head, and can be used in various activities, including but not limited to daily life, sports, work and military activities, such as bicycle helmets, ski helmets, roller skating helmets, climbing helmets, equestrian helmets, baseball catcher helmets, hockey helmets, safety helmets (for construction or industrial use), tactical helmets (for military or tactical use), fire helmets, and riot helmets (for police or security use). The three-dimensional printed buffer structure 10 disclosed herein can, for example, be disposed on the inner side of the hard shell of the helmet (i.e., the side of the helmet close to the user's head) to serve as the inner liner of the helmet, and can directly contact the user's head. Figure 2 is a partially enlarged schematic diagram of region R1 of the 3D printed cushioning structure 10 in Figure 1. Please refer to Figures 1 and 2 together. The 3D printed cushioning structure 10 includes a first cushioning layer 100, which includes an outer surface portion O, an inner surface portion I, and a plurality of support members 130. The outer surface portion O is relatively close to the helmet shell, while the inner surface portion I is relatively close to the user's head. The support members 130 are disposed and connected between the outer surface portion O and the inner surface portion I. The outer surface portion O of the first buffer layer 100 includes a plurality of first rods 110. The plurality of first rods 110 are cross-configured to form a grid G ​​having a plurality of intersection points P, and define the outer contour of the shell close to the helmet, that is, define the contour of the outer surface portion O of the first buffer layer 100. The geometric features of the grid G ​​disclosed herein are in a two-dimensional distribution pattern, and the whole constitutes a continuous and complete two-dimensional grid structure. To facilitate understanding of the structural pattern of the grid G, please first refer to Figure 3, which is a partially enlarged schematic diagram of the area R2 of the three-dimensional printed buffer structure 10 in Figure 1 after adjusting the viewing angle. As shown in Figure 3, the four first rods 110a, 110b, 110c, and 110d are together surrounded by a grid unit GU, and the plurality of grid units GU are tightly spliced ​​on the same surface (for example, the surface where the arc-shaped curved surface Q marked in Figure 3 is located) to form a grid G ​​with a complete two-dimensional grid structure. Compared to a fully filled structure (a fully solid structure), the mesh G formed by the cross-section of the first rods 110 has greater room for deformation when subjected to external forces (impact). This highly flexible yet controllable deformation evenly distributes stress, thereby reducing the damage caused by concentrated stress in a single area. Furthermore, the non-filled design of the mesh G contributes to lightweight construction and provides good breathability, thereby ensuring comfortable wear. On the other hand, the cross-sectional arrangement of the multiple first rods 110 creates a plurality of hollow areas S1 between them. The hollow areas S1 formed by the first rods 110 not only reduce structural rigidity but also provide additional cushioning space, allowing the first rods 110 to flexibly deform in multiple directions when subjected to external forces, thereby enhancing energy absorption and release, and thereby reducing the impact load on the user's head. In some embodiments, the mesh G can have a variety of opening shapes (i.e., the shape of the hollow areas S1), such as, but not limited to, triangles, quadrilaterals (e.g., parallelograms, rectangles, trapezoids, rhombuses, trapezoids, etc.), hexagons (e.g., honeycomb shapes), or combinations thereof, to provide protection tailored to different usage scenarios. This embodiment uses a rectangle as an example. Please return to Figure 2. The inner surface portion I of the first buffer layer 100 includes a plurality of second rods 120. The plurality of second rods 120 extend continuously and are spaced apart from each other without intersecting, and define an inner contour close to the user's head, that is, define the contour of the inner surface portion I of the first buffer layer 100. In some embodiments, the inner surface portion I may directly contact the user's head. By designing the plurality of second rods 120 to be arranged adjacent to each other and extending continuously without overlap while maintaining a gap between each other, it can not only conform to the shape of the user's head to provide good fit (compliance), but also evenly distribute pressure to reduce local point pressure, thereby improving wearing comfort. On the other hand, there is a spacing area S2 between adjacent second rods 120. The spacing area S2 can help improve breathability, allowing airflow to flow between the rods in a specific direction, thereby improving the heat dissipation effect of the head to reduce the feeling of stuffiness when wearing. In some embodiments, to accommodate the shape of different head regions, the second rods 120 may have different arrangements corresponding to different head regions, and within the same region, they may extend generally in a single direction. The head will be divided into multiple regions, with Figure 1 providing an exemplary illustration. In the embodiment of Figure 1, the second rods 120 extend generally from the forehead (including the forehead, temples, and forehead sides) to the top of the head in the region corresponding to the front of the head (the upper portion of Figure 1). In the region corresponding to the middle of the head (the middle portion of Figure 1), they extend generally from the left and right earlobes to the top of the head. In the region corresponding to the back of the head (the lower portion of Figure 1), they extend generally from the right (left) side of the head to the left (right) side of the head. This design avoids the potential problem of the second rods 120 extending in the same direction throughout the entire first cushioning layer 100. For example, if the second rod 120 extends from the forehead to the back of the head throughout the first cushioning layer 100, when external force is applied from the forehead or the back of the head, the helmet will be easily pushed along the extension direction of the second rod 120 of the first cushioning layer 100, and there will be less resistance in directions other than the extension direction of the second rod 120, resulting in relative displacement between the helmet and the head, thereby reducing the protective effect. In contrast, some embodiments of the present disclosure design the second rod 120 with different extension directions in different areas, resulting in a multi-directional arrangement of the second rod 120. This allows the helmet to maintain a stable and fixed position on the head, effectively dispersing and resisting external forces from all directions, and enhancing the overall protective performance of the helmet. Overall, the design of the extension direction of the second rod 120 effectively reduces the possibility of external forces being transmitted along an axis perpendicular to the extension direction. Furthermore, due to its perpendicular extension direction, the second rod 120 can provide stable friction against external forces perpendicular to the extension direction of the second rod 120, helping to reduce or prevent displacement of the first buffer layer 100 in a direction perpendicular to the extension direction of the second rod 120. This effectively suppresses slippage or deflection, further enhancing the stability of the structure and the protective effect of the user. It's worth noting that while the second rod 120 may adopt different arrangement patterns at different locations, it achieves smooth transitions between these different locations, allowing the second rod 120 to appear continuous at the transitions. This allows the two sections of the second rod 120 to be integrated into a seamless, uniformly extended section of the second rod 120. In other words, after the smooth transition, the two sections of the second rod 120 can be considered a single, continuously extended section of the second rod 120. This smooth transition not only reduces the possibility of stress concentration at non-seamless transitions but also evenly distributes external forces along the continuously extended second rod 120, further reducing the risk of localized deformation or damage. Please go back to Figure 2. In some embodiments, the second rod 120 can also be appropriately bent or transitionally designed in different areas according to the special geometric characteristics of the user's head, while maintaining a certain degree of spacing distribution, and the spacing D between the second rods 120 can also be adjusted accordingly according to the geometric characteristics of the user's head, such as reducing the spacing D in areas that require higher support, or increasing the spacing D in areas that require greater cushioning or avoidance, thereby taking into account the support, cushioning and fit (compliance) of the entire structure. The following will be illustrated by examples of Figures 4A and 4B, where Figure 4A is a partially enlarged schematic diagram of area R3 of the three-dimensional printed buffer structure 10 in Figure 1 after the viewing angle is adjusted, and Figure 4B is a partially enlarged schematic diagram of area R4 of the three-dimensional printed buffer structure 10 in Figure 1 after the viewing angle is adjusted. FIG4A , separated by dashed lines, illustrates the distribution of the second rods 120 in the first cushioning layer 100 from region R31 corresponding to the forehead to region R32 corresponding to the top of the head. Overall, the multiple second rods 120 gradually converge from region R31 corresponding to the forehead to region R32 corresponding to the top of the head (i.e., the spacing D between the second rods 120 gradually decreases). In region R32 corresponding to the top of the head, they curve appropriately based on the shape of the hair whorls on the scalp. To further adapt to the curve of the head, some second rods 120 can further smoothly merge with other second rods 120 during the curve (or be considered to merge and extend). For example, in FIG4A , second rods 120a extend generally in the same direction in region R31 corresponding to the forehead, then bend in region R32 corresponding to the top of the head to smoothly merge with second rods 120b, which also extend from region R31 to region R32, thereby forming a single, curved second rod 120. This design enables the second rod 120 to conform to the natural curve of the hair whorl, providing uniform support and a comfortable fit while avoiding pressure on the hair whorl area. It should be understood that while some second rods 120 can smoothly connect with other second rods 120 during extension, this occurs only where the second rods 120 need to adapt to larger directional changes or structural transitions. In other words, smooth connection occurs primarily in areas with specific geometric characteristics that require adaptability (e.g., the area corresponding to the hair whorl described in FIG. 4A ). Overall, most second rods 120 maintain a roughly consistent extension direction within a single region of the first cushioning layer 100, thereby adapting to the head shape corresponding to that region over a large area and maintaining the structural consistency of the inner surface portion I of the first cushioning layer 100, thereby providing uniform support. Figure 4B, separated by dashed lines, illustrates the distribution of the second rods 120 in the first cushioning layer 100 from region R41 corresponding to the back of the head to region R42 corresponding to the side of the ear. Overall, the multiple second rods 120 extend continuously from region R41 corresponding to the back of the head to region R42 corresponding to the side of the ear. In region R42 corresponding to the side of the ear, they are designed to bend to conform to the contours of the ear, thus preventing pressure and stuffiness on the ear. For example, the second rods 120c in Figure 4B extend in a generally uniform direction in region R41 corresponding to the back of the head, but then curve in a lightning-shaped pattern in region R42 corresponding to the side of the ear. Adjacent second rods 120 are approximately equidistant from region R41 corresponding to the back of the head to region R42 corresponding to the side of the ear. This lightning-shaped curve flexibly adapts to the complex curves around the ear, helping to conform to the curvature of the head while effectively avoiding the contours of the ear, thereby enhancing the overall wearing comfort and stability of the structure. In some embodiments, the second rod 120 may be designed to be bent in a lightning shape at the edge of the first buffer layer 100 (for example, the edge at the back of the head shown at the bottom of FIG. 1 ) to increase friction on the head and thereby improve wearing stability. Please refer to Figures 2 and 5A simultaneously, wherein Figure 5A is a partially enlarged schematic diagram of region R5 of the 3D-printed cushioning structure 10 in Figure 2. The support member 130 connects the outer surface portion O and the inner surface portion I of the first cushioning layer 100. Specifically, the support member 130 has a first end 130a and a second end 130b that are opposite to each other, and the first end 130a and the second end 130b are respectively connected to any one of the first rods 110 and any one of the second rods 120. Because the support member 130 can firmly connect the first rod 110 and the second rod 120 together, when an external force is applied to the helmet in a direction non-perpendicular to the top of the head (i.e., lateral), the relative displacement between the first rod 110 and the second rod 120 in the lateral direction can be effectively limited. At the same time, combined with the friction between the second rod 120 and the head, the second rod 120 and the support member 130 can jointly pull the first buffer layer 100 and the helmet back to their original position, thereby reducing the lateral displacement or rotation of the helmet caused by the lateral force, effectively reducing the relative movement between the helmet and the user's head, improving wearing stability and enhancing the protective effect. Furthermore, when the first cushioning layer 100 is subjected to an external force, the support members 130 deflect in response to the limited relative displacement between the first rods 110 and the second rods 120. This deflection redistributes the stress originally concentrated at a single point to a wider area. More specifically, when an external force is applied to the first cushioning layer 100 perpendicular to the force-bearing surface (e.g., the outer surface O of the first cushioning layer 100), the deflection of the support members 130 converts this vertical force into a horizontal force. This horizontal force is further dispersed along the two-dimensional grid structure formed by the first rods 110 and the continuously extending structure formed by the second rods 120 (e.g., along the contours of the outer surface O and the inner surface I of the first cushioning layer 100), thereby reducing the damage caused by localized stress concentration at a single point. In addition, the support member 130 also has good deflection recovery performance, and can temporarily store energy inside it when subjected to external force, and use its own rebound to quickly release the energy to generate a restoring force after the external force disappears, thereby pulling the second rod 120 back to its original position. Furthermore, because the force perpendicular to the load-bearing surface is guided and dispersed to the first and second rods 110, 120 by the deflected multiple support members 130, and further transmitted toward the surrounding areas along the extension direction of the first and second rods 110, 120, the vertical compression of the first buffer layer 100 during load-bearing is effectively reduced, thereby effectively reducing the deformation of the overall structure. Furthermore, due to the reduced vertical compression, the wear and fatigue accumulation caused by localized compression of the first buffer layer 100 during load-bearing is effectively reduced, thereby enabling the first buffer layer 100 to maintain its long-term stable support and cushioning effect. In some embodiments, the support members 130 primarily utilize the first rods 110 arranged in the grid G ​​as a base to support the second rods 120. Consequently, multiple support members 130 are connected to the first rods 110 based on the positions of the second rods 120, forming a spaced arrangement. Specifically, as shown in FIG5A , assuming that the extension direction of a second rod 120 is substantially the same as the arrangement direction of a first rod 110 in the grid G, the support members 130 can be spaced and connected to the first rods 110 at intersection points P or non-intersection points (e.g., at rod-shaped sections of the first rods 110). In some embodiments, the support member 130 may be a straight column. In other words, the support member 130 does not have a curved or curved shape. Through the straight column design, the support member 130 can have a higher support (compression resistance), so that it can effectively resist compression when subjected to stress along the column axis, maintain structural stability, and enable it to adapt to deflection at various angles when subjected to oblique stress (i.e., stress not along the column axis), and disperse the stress to the surroundings. In addition, the straight column-shaped support member 130 is not prone to unexpected deformation after being subjected to force, and has a relatively predictable and controllable mechanical response performance, reducing the unstable shaking or displacement of the helmet when subjected to external force, thereby reducing the relative displacement between the helmet and the user's head, and improving wearing safety. In some embodiments, the connection angle θ between the support member 130 and the first rod 110 and between the support member 130 and the second rod 120 may be 45 degrees to 135 degrees (e.g., 50 degrees, 55 degrees, 60 degrees, 65 degrees, 70 degrees, 75 degrees, 80 degrees, 85 degrees, 90 degrees, 95 degrees, 100 degrees, 105 degrees, 110 degrees, 115 degrees, 120 degrees, 125 degrees, or 130 degrees). It should be noted that the definition of the connection angle θ herein refers to the connection angle θ between different support members 130 and the first rod 110 and the second rod 120, respectively, in their designs. When the connection angle θ falls within the above range, the support member 130 can have both supporting and deflecting effects, which helps to disperse stress in conjunction with the first rod 110 and the second rod 120. The overall structure has better deflection recovery and higher lateral rigidity, which can maintain the stability of the structure and prevent the connection from being too small (less than 45 degrees, such as 10 degrees) or too large (greater than 135 degrees, such as 170 degrees) Angle leads to insufficient support force and thus fails to provide effective deflection. In some embodiments, at least part of the first end 130a of the support member 130 needs to be connected to the intersection P of the grid G. Compared to the non-intersection points of the grid G ​​(i.e., the rod-shaped section of the first rod 110), the intersection P has higher structural strength and stability, which can provide the support member 130 with sufficient load-bearing capacity to more effectively and directly transfer stress to the entire grid system. In addition, connecting the support member 130 to the intersection P can also increase the connection strength between the support member 130 and the grid G, thereby improving the deformation resistance of the overall structure. In actual design, the connection positions of multiple support members 130 in the first buffer layer 100 and the grid G ​​can be adjusted or matched according to the use scenario and protection requirements of the helmet, and are not limited to connection only at the intersection P or non-intersection points. The multiple support members 130 have hollow areas S3 between them, meaning the support members 130 are spaced apart. In some embodiments, the hollow areas S1 between the first rods 110 and the spaced areas S2 between the second rods 120 can communicate with each other through the hollow areas S3 between the support members 130 (see Figure 2 ). This creates a gas exchange cavity that extends continuously from the outer surface O of the first cushioning layer 100 to the inner surface I. In other words, the hollow areas S1, the spaced areas S2, and the hollow areas S3 are connected to form the gas exchange cavity. This continuously extending gas exchange cavity redistributes air pressure generated by external impact over a larger area, helping to improve cushioning. Furthermore, the gas exchange cavity promotes air circulation, preventing heat and moisture from accumulating inside the helmet, thereby reducing stuffiness and keeping the head dry. In some embodiments, the length L of the support member 130 can be, for example, 3 cm to 10 cm (e.g., 4 cm, 5 cm, 6 cm, 7 cm, 8 cm, 9 cm). Designing within this length range helps the support member 130 strike a balance between its deflection and uniform stress distribution. Specifically, if the support member 130 is too long, while it may provide a larger deflection amplitude to absorb more energy, it may also experience excessive deformation during deflection, resulting in a reduction in the deflection recovery ability of the support member 130. An overly long support member 130 may also result in an excessively large stress transfer path, making it impossible to effectively and evenly transfer stress to the first rod 110 and the second rod 120, resulting in uneven stress distribution. If the support member 130 is too short, the deflection capacity is limited, and the stress cannot be fully absorbed and distributed, resulting in local stress concentration at a single point. In some embodiments, the length L of the support member 130 of the first buffer layer 100 can be designed based on the location of the helmet area. For example, support members 130 in the same area can be designed to have the same length L. In some embodiments, the support members 130 of the first cushioning layer 100 of the entire helmet are designed to have the same length L. Please refer to Figure 5B, which is a structural example of a support member 130 according to other embodiments of the present disclosure, and the area presented corresponds to area R5 of the three-dimensional printed buffer structure 10 in Figure 2. In the embodiment of Figure 5B, adjacent support members 130 intersect with each other at the second rod 120. In other embodiments (not shown), adjacent support members 130 may also intersect with each other at the first rod 110. When the support members 130 intersect at one point on the first rod 110 or the second rod 120, the point becomes a dispersion center for multi-directional forces, which can more evenly distribute external forces to all rod-shaped structures connected thereto (e.g., the first rod 110, the second rod 120, and the support member 130), helping to reduce the occurrence of local stress concentration. In some other embodiments (not shown), adjacent support members 130 may intersect to form a cross structure in the space between the first rod 110 and the second rod 120. In addition to the connection points between the support members 130 and the first rod 110 and the second rod 120, an intersection point is added to increase the stress dispersion path, and the cross structure provides additional structural support to enhance the deformation resistance of the first buffer layer 100 in all directions. Please return to Figure 2. In some embodiments, the entire first cushioning layer 100 can be three-dimensionally printed. That is, the first rod 110, the second rod 120, and the support member 130 in the first cushioning layer 100 are integrally formed. The seamless integration and material continuity of this integrated molding can avoid potential seam weaknesses and material interface weaknesses, thereby improving overall stress transfer efficiency and more evenly distributing stress on the helmet throughout the first cushioning layer 100, reducing localized stress concentration. In some embodiments, the first buffer layer 100 as a whole can be foamed after being three-dimensionally printed into one piece. That is, each first rod 110, each second rod 120, and each support member 130 in the first buffer layer 100 can each have multiple pore structures. Please refer to Figure 6, which is a cross-sectional microscopic schematic diagram of the first rod 110, the second rod 120, or the support member 130 according to some embodiments of the present disclosure, which shows a pore structure H. The pore structure H can provide additional space to accommodate compression deformation, effectively disperse and mitigate external force impact to provide additional cushioning and support effects. In addition, the pore structure H can reduce the amount of material used in the first buffer layer 100 while maintaining sufficient strength, thereby achieving a balance between achieving lightweight and improving strength. In addition, the pore structure H can enhance breathability, thereby improving wearing comfort. In some embodiments, the cell structure H may have a micron scale, that is, the pore size of a single cell structure H may be 10 to 800 microns (e.g., 100, 200, 300, 400, 500, 600, or 700 microns). Compared to nanoscale cell structures H, microscale cell structures H are less likely to collapse or deform, thereby providing longer-lasting cushioning and support. Furthermore, microscale cell structures H can provide relatively high air permeability, thereby providing a better wearing experience. In some embodiments, the first rod 110, the second rod 120, and the support member 130 in the first cushioning layer 100 are made of the same material. In some embodiments, the first rod 110, the second rod 120, and the support member 130 can be made of an elastomeric material, including but not limited to thermoplastic polyurethane, a polyurethane-based material, expanded polystyrene, and foam, so that the first cushioning layer 100 has flexibility and plasticity, thereby flexibly conforming to the natural curves of the head and avoiding pressure or discomfort caused by rigid structures on the head. Please continue to refer to Figure 2. In some embodiments, the three-dimensional printed buffer structure 10 may further include a second buffer layer 200 disposed between the outer surface portion O of the first buffer layer 100 and the outer shell of the helmet. When the helmet is subjected to an external force, the external force may sequentially pass through the second buffer layer 200 and the first buffer layer 100 to reach the user's head. In some embodiments, the second buffer layer 200 may include a plurality of lattice structure units 210 continuously arranged in a three-dimensional space. In some embodiments, the lattice structure unit 210 may be an expansion or three-dimensional extension of a grid G ​​of a two-dimensional structure in a three-dimensional space. For example, the lattice structure unit 210 may be a cubic lattice structure extended in a three-dimensional space by the grid G ​​of a quadrilateral structure as shown in Figure 2, and may be further designed as a multi-layer structure based on the overall buffering capacity requirements. In the embodiment of Figure 2, the second buffer layer 200 is a three-layered structure. In other embodiments, the lattice structure of the lattice structure unit 210 may be replaced by a lattice structure as shown in Figures 7A to 7H, such as the body-centered cubic lattice in Figure 7A, the face-centered cubic lattice in Figure 7B, the fluorite lattice in Figure 7C, the Kelvin lattice in Figure 7D, the gyroid lattice in Figure 7E, the Schwarz lattice in Figure 7F, the diamond lattice in Figure 7G, and the split-P lattice in Figure 7H. Overall, the second buffer layer 200 achieves the effect of directly absorbing stress applied perpendicular to the stress-bearing surface through a non-filled structural design composed of a plurality of lattice structure units 210. In some embodiments, the hollow area S4 in the lattice structure unit 210 may also be connected to the hollow area S1 between the first rods 110, the spacing area S2 between the second rods 120, and the hollow area S3 between the support members 130 to form a gas exchange cavity that extends continuously from the inner surface portion I of the first buffer layer 100 to the outer surface portion U of the second buffer layer 200. In some embodiments, the first cushioning layer 100 and the second cushioning layer 200 can be integrally formed by three-dimensional printing. That is, the first rods 110, the second rods 120, and the support members 130 in the first cushioning layer 100 are integrally formed with the lattice structure units 210 in the second cushioning layer 200. In other embodiments, the second cushioning layer 200 can be combined with the first cushioning layer 100 by suitable means such as gluing, mechanical connection (e.g., mortise and tenon joints or snap fasteners), welding (e.g., heat-melt welding, ultrasonic welding), or additional mounting fixtures, to provide flexibility in design and assembly. In some embodiments, the second buffer layer 200 as a whole may also be foamed after being three-dimensionally printed as a whole. That is, each lattice structure unit 210 in the second buffer layer 200 may have multiple bubble structures H in the first buffer layer 100 as shown in FIG. 6 . It is worth noting that the design of the first cushioning layer 100 in this disclosure focuses on the function of "reducing lateral displacement or rotation of the helmet" provided by the support member 130. Specifically, the support member 130 limits the relative displacement between the first rod 110 and the second rod 120, and the friction between the second rod 120 and the head resists lateral displacement or rotation of the first cushioning layer 100 caused by lateral forces. Furthermore, the support member 130 also functions to "redistribute stress" (or disperse stress). Specifically, the deflection of the support member 130 converts stress applied vertically to the load-bearing surface into horizontal forces. These horizontal forces are further distributed and transmitted to the surrounding area through the two-dimensional grid structure of the first rod 110 and the continuously extended structure of the second rod 120. This allows multiple horizontal rod-shaped structures (e.g., the first rod 110 and the second rod 120) to collaboratively bear the vertically applied load, thereby reducing the damage caused by localized stress concentration at a single point. In some embodiments, the additional second buffer layer 200 can further provide the function of "absorbing vertical stress". Specifically, the geometric characteristics of the lattice structure unit 210 (for example, the three-dimensional distribution and cavity design of the lattice structure) and the elasticity of the material directly absorb the stress applied vertically to the stress surface, thereby reducing the energy transferred by the stress to the inner layer. In other words, the first buffer layer 100 and the second buffer layer 200 achieve the buffering effect through different means. Overall, the first buffer layer 100 itself can achieve good protective performance through its ability to "limit lateral displacement or rotation of the helmet" and "redistribute stress". By further combining the first buffer layer 100 with the second buffer layer 200, the buffering and protective effects can be further enhanced by "absorbing vertical stress", thereby enhancing the overall protective performance of the helmet and providing more comprehensive safety protection. According to the above-mentioned embodiment of the present disclosure, by using a non-filled grid design (first rod) to form the outer surface portion of the first buffer layer, external forces can be dispersed over a wider range, reducing the damage caused by concentrated stress to a single area and effectively reducing the risk of injury. By using continuous rods (second rods) that extend continuously and do not intersect with each other to form the inner surface portion of the first buffer layer, not only can good head fit (compliance) be provided, but in combination with the design of the support member, the friction of the first buffer layer on the head in a specific direction can also be enhanced, thereby limiting the relative displacement between the helmet and the head, thereby limiting the lateral deviation or rotation of the helmet and enhancing the wearing stability of the helmet. In addition, through the deflection of the support member, the horizontal first rod and the second rod can share the vertically applied load, achieving a stress dispersion effect. Overall, through the synergistic effect of the first rod, the second rod and the support member, the present disclosure can improve the overall protective performance and wearing stability of the helmet in a way that is different from "directly absorbing vertical stress." Although the present disclosure has been disclosed above in the form of implementation methods, it is not intended to limit the present disclosure. Anyone skilled in the art may make various changes and modifications without departing from the spirit and scope of the present disclosure. Therefore, the scope of protection of the present disclosure shall be determined by the scope of the appended patent applications. 10: 3D printed buffer structure 100: first buffer layer 110, 110a, 110b, 110c, 110d: first rod 120, 120a, 120b, 120c: second rod 130: support member 130a: first end 130b: second end 200: second buffer layer 210: lattice structure unit Q: curved surface H: cell structure θ: connection angle L: length D: spacing P: intersection G: grid GU: grid unit O, U: outer surface portion I: inner surface portion S1, S3, S4: hollow area S2: spacing area R1, R2, R3, R31, R32, R4, R41, R42, R5: area To make the above and other objects, features, advantages and embodiments of the present disclosure more clearly understood, the accompanying drawings are described as follows: FIG1 is a three-dimensional schematic diagram of a three-dimensional printed cushioning structure applied to a helmet according to some embodiments of the present disclosure; FIG2 is a partially enlarged schematic diagram of region R1 of the three-dimensional printed cushioning structure of FIG1; FIG3 is a partially enlarged schematic diagram of region R2 of the three-dimensional printed cushioning structure of FIG1 after adjusting the viewing angle; FIG4A is a partially enlarged schematic diagram of region R3 of the three-dimensional printed cushioning structure of FIG1 after adjusting the viewing angle; FIG4B is a partially enlarged schematic diagram of region R4 of the three-dimensional printed cushioning structure of FIG1 after adjusting the viewing angle; FIG5A is a partially enlarged schematic diagram of region R5 of the three-dimensional printed cushioning structure of FIG2; FIG5B is a structural state of a support member according to other embodiments of the present disclosure, and the region presented corresponds to region R5 of the three-dimensional printed cushioning structure of FIG2; FIG6 is a cross-sectional microscopic schematic diagram of a first rod, a second rod or a support member according to some embodiments of the present disclosure; and FIG7A to FIG7H are schematic diagrams of the lattice structure units according to different embodiments of the present disclosure. 100: first buffer layer 110: First shot 120: Second shot 130: Support 200: Second buffer layer 210: Lattice structure unit D: Spacing P: Intersection point G: Grid O, U: Outer surface I: Inner surface S1, S3, S4: hollow area S2: spacer area R1, R5: Area

Claims

1. A three-dimensional printed buffer structure for a helmet, comprising: A first buffer layer comprises: an outer surface portion, comprising a plurality of first rods, wherein the first rods are arranged to cross each other to form a grid and define an outer contour close to an outer shell of the helmet; an inner surface portion, comprising a plurality of second rods, wherein the second rods extend continuously and are spaced adjacent to each other without intersecting, and define an inner contour close to a user; and a plurality of support members arranged between the outer surface portion and the inner surface portion, each of the support members having a first end and a second end, wherein the first end and the second end of any one of the support members are respectively connected to any one of the first rods and any one of the second rods; wherein the first rods, the second rods and the support members are integrated by three-dimensional printing.

2. The three-dimensional printing buffer structure according to claim 1, wherein any one of the support members is a straight column member.

3. A three-dimensional printed buffer structure as described in claim 2, wherein a first connection angle between any one of the support members and one of the first rods connected thereto is 45 degrees to 135 degrees, and a second connection angle between any one of the support members and one of the second rods connected thereto is 45 degrees to 135 degrees.

4. The three-dimensional printing buffer structure according to claim 1, wherein the first end of any one of the support members is connected to an intersection of the grid.

5. The three-dimensional printing buffer structure as described in claim 1, wherein any two or more adjacent support members intersect with each other.

6. In the three-dimensional printed buffer structure according to claim 5, any two or more adjacent support members intersect at any one of the first rods or any one of the second rods.

7. The three-dimensional printing buffer structure according to claim 1 further comprises: A second buffer layer is connected to the outer surface portion and is disposed between the outer surface portion and the outer shell of the helmet. The second buffer layer includes a plurality of lattice structure units, and each of the lattice structure units has a hollow area.

8. The three-dimensional printed buffer structure as described in claim 7, wherein the first rods, the second rods, the support members and the lattice structure units are integrated by three-dimensional printing.

9. The three-dimensional printed buffer structure according to claim 1, wherein each of the first rods, each of the second rods, and each of the support members each has a plurality of cellular structures.

10. A three-dimensional printed buffer structure as described in claim 1, wherein there are multiple first hollow areas between the first rods, multiple second hollow areas between the second rods, multiple third hollow areas between the support members, and the first hollow areas, the second hollow areas and the third hollow areas are connected.

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