A composite cushioning structure for shoe soles, a preparation method thereof, and a shoe sole.

Abstract

This invention provides a composite cushioning structure, a manufacturing method, and a sole for shoe soles. The composite cushioning structure has an outer shell with an outer covering and an air cushion layer. The air cushion layer includes a plurality of cushioning units stacked laterally. Each cushioning unit is a body of revolution formed by sidewalls surrounding its periphery and extending about a vertically extending longitudinal axis. The sidewalls form a plurality of alternating outward and inward extending arc segments on a vertical cross-section passing through the longitudinal axis, with adjacent vertically adjacent arc segments smoothly connected. A portion of the cushioning units encloses a receiving cavity. The outer covering seals the upper and / or lower ends of the cushioning units outside the receiving cavity. A foam component is housed within the receiving cavity and forms a heat-fused bonding interface with at least a portion of the inner wall of the receiving cavity. The vertical dimension of the foam component is 25% to 40% of the vertical dimension of the outer shell, and the foam component is located in the middle of the vertical direction of the outer shell. This composite cushioning structure is beneficial for improving the cushioning performance of the shoe sole and for improving the retention of cushioning performance after long-term use.

Description

Technical Field

[0001] This invention relates to the field of shoe sole cushioning structures, specifically to a composite cushioning structure for shoe soles, a preparation method thereof, and a shoe sole. Background Technology

[0002] The cushioning structure of shoe soles often uses physical foam materials. Physical foam materials have a low density, resulting in a soft initial feel and providing a certain degree of cushioning. However, after prolonged wear and repeated impacts, the internal pores of the foam material may be damaged, and the material thickness may also decrease. This leads to a decline in shock absorption performance, and the cushioning effect felt by the wearer diminishes over time. Summary of the Invention

[0003] The purpose of this invention is to solve the problem of cushioning degradation of single foam materials after long-term repeated pressure on shoe soles, and to disclose a composite cushioning structure for shoe soles, a preparation method thereof, and a shoe sole. This composite cushioning structure forms a staged pressure-bearing fit between the cushioning unit in the outer shell and the foam component disposed within the accommodating cavity, which is beneficial for improving the cushioning performance of the shoe sole and enhancing the retention of cushioning performance after long-term use.

[0004] To achieve the above objectives, the following technical solution is adopted: In at least one embodiment, a composite cushioning structure for a shoe sole is disclosed, the composite cushioning structure for a shoe sole comprising a shell and a foam component; the shell has an outer covering layer and an air cushion layer; the air cushion layer comprises a plurality of cushioning units stacked laterally; each cushioning unit is a body of revolution surrounded by sidewalls on its periphery and formed about a vertically extending longitudinal axis, the sidewalls forming a plurality of alternating outward and inward extending arc segments from top to bottom on a vertical cross-section passing through its longitudinal axis, and the vertically adjacent arc segments are smoothly connected; a portion of the cushioning units is arranged to form a receiving cavity, the receiving cavity having a... The cushioning unit has a lateral inner wall formed by its sidewalls, and a top wall and a bottom wall that respectively cover the upper and lower ends of the cushioning unit; the outer cover covers the upper and / or lower ends of the cushioning unit outside the accommodating cavity; the foam is housed in the accommodating cavity, with its peripheral, upper, and lower sides facing the lateral inner wall, top wall, and bottom wall respectively, and forming a heat-fused bonding interface with at least a portion of the inner wall of the accommodating cavity; the vertical dimension of the foam is 25% to 40% of the vertical dimension of the outer shell, and the foam is located in the middle of the vertical direction of the outer shell.

[0005] In the above design, when conventional foam materials are used as the main cushioning material for the sole, they mainly rely on the compression of the foam cells to absorb impact. However, after prolonged pressure, the thickness decreases and the cushioning weakens. This invention adjusts the pressure-bearing method of this single material so that the cushioning units in the air cushion layer within the outer shell participate in the stress first. The sidewalls of the cushioning units form a rotating body around the vertical axis, and on the vertical cross-section, they form alternating outward and inward extending arc segments. When the sole is subjected to a landing impact, the outer layer transfers the load to the air cushion layer. The arc segment sidewalls can continuously bend along the smooth joints, allowing the outer shell to absorb and disperse some of the impact energy first. Simultaneously, the air pressure inside the sealed cushioning unit also stores and releases energy. In this way, the outer shell itself can already provide a certain level of cushioning performance.

[0006] However, if the cushioning unit structure alone is used for buffering, the outer shell needs to simultaneously absorb energy in the initial stage and provide support in the later stage. As the impact continues to increase or is repeated, the bending deformation of the cushioning unit may concentrate in local areas, and the sole may still experience insufficient cushioning retention after fatigue.

[0007] To address this, this design encloses a portion of the damping units to form a cavity, within which the foam component is placed. The lateral inner wall of the cavity is formed by the sidewalls of the damping units, while the top and bottom walls respectively seal the upper and lower ends of the corresponding damping units, maintaining their airtightness. The peripheral, upper, and lower sides of the foam component face the lateral inner wall, top wall, and bottom wall, respectively, allowing it to participate in subsequent buffering under the circumferential restraint and vertical clamping provided by the cavity. In this way, the damping units in the shell first bend to absorb energy, and the foam component is subsequently compressed in a controlled manner; the two work synergistically to improve the long-term maintenance of damping performance. Specifically, in the above design, the vertical dimension of the foam component is limited to 25% to 40% of the vertical dimension of the shell. The shell retains sufficient air cushion structure above and below the foam component to form recoverable bending clearance in the initial impact phase; the foam component also has sufficient thickness to participate in subsequent compression, preventing it from only serving a local filling function due to being too thin. If the proportion of foam components is too large, the deformation path of the sidewalls of the air cushion layer will be shortened, making it difficult for the outer shell to fully exert its initial energy absorption function; if the proportion of foam components is too small, the foam components will not absorb the load in the middle and rear sections sufficiently, and the sole is prone to sudden changes in support. Therefore, the above proportions ensure that the structural deformation of the outer shell and the material compression of the foam components form a continuous connection.

[0008] In the above design, the foam component is located in the middle of the vertical direction of the outer shell, allowing the outer shell structure above and below the foam component to participate in load transfer. When an impact enters from the upper or lower side of the sole, the load first passes through the corresponding outer layer and air cushion layer, and then is transferred to the foam component. Subsequently, the foam component and the outer shell structure on the opposite side jointly complete the cushioning. This middle position prevents the foam component from being too close to one side surface, causing the air cushion layer on the other side to lose effective deformation space, and also prevents the foam component from being offset, causing local hard spots or local collapse. Thus, the flexible structure of the outer shell and the compressible structure of the foam component can form a more balanced superimposed cushioning path in the vertical direction.

[0009] In the above design, the hot-melt bonding interface forms a bond between the shell and the foam component. Under repeated compression and unloading, the foam component is less prone to slippage relative to the accommodating cavity, and less likely to partially separate from the top, bottom, or lateral inner walls. This interface facilitates the smooth transfer of load from the initial deformation of the shell to the foam component, and allows the foam component to return to its predetermined position with the shell during unloading. Thus, the conventional single-pressure bearing method of foam materials is transformed into a composite buffering path: the damping unit first absorbs initial energy, the accommodating cavity limits the foam component, the foam component then undergoes subsequent compression, and the hot-melt bonding interface stably transmits force. This composite damping structure can prolong the impact buffering process, reduce instantaneous impact concentration, and help improve the maintenance of damping performance after long-term use.

[0010] In the composite cushioning structure for shoe soles disclosed in at least one embodiment, preferably, in two laterally adjacent cushioning units, the sidewall portion of the outwardly extending arc segment of one cushioning unit is opposite to the sidewall portion of the inwardly extending arc segment of the other cushioning unit within the same vertical height range, and the outer wall surfaces of the sidewalls of the two adjacent cushioning units are at least partially in contact with each other within the same vertical height range.

[0011] In the above design, the convex and concave sidewalls of adjacent damping units are opposite each other within the same height range, forming a mutually supportive contact surface between adjacent units. When a damping unit is subjected to compression and bending, its outer sidewall surface can transmit the lateral component of the force to adjacent damping units through this contact surface, reducing local outward expansion or collapse of a single damping unit. This structure also allows the deformation spaces of adjacent arc segments to be staggered, reducing the possibility of mutual interference between adjacent units under pressure, thereby improving the overall support stability of the air cushion layer.

[0012] In a composite cushioning structure for a shoe sole disclosed in at least one embodiment, preferably, the outer cover includes a lower cover portion located below the air cushion layer; at least a portion of the cushioning units form a straight segment below all the arc segments, the lower end of the straight segment being connected to the lower cover portion, and the upper end of the straight segment being smoothly connected to the lowermost arc segment.

[0013] In the above design, the lower cover provides continuous support for the underside of the air cushion layer. The straight segment is located below the curved segment and connects with the lower cover, forming a relatively stable support boundary near the ground. The deformation capacity of the straight segment is relatively lower than that of the curved segment, thus suppressing excessive compression at the lower end of the damping unit. The smooth connection between the straight segment and the lowest curved segment also makes it less likely for sharp stress concentrations to form when the force transitions from the bottom support area to the deformation area of ​​the curved segment.

[0014] In the composite cushioning structure for shoe soles disclosed in at least one embodiment, preferably, the inner side wall of the accommodating cavity is formed by an arc segment portion of the corresponding cushioning unit; the periphery of the foaming member is connected to the protruding portion of the arc segment of the corresponding cushioning unit to form a gap with the concave portion of the arc segment.

[0015] In the above design, the inner side wall of the accommodating cavity is composed of an arc segment, so that the periphery of the foam component faces the side wall region that can undergo bending deformation. When the periphery of the foam component comes into contact with the protruding part of the arc segment, the protruding part can serve as a local support and load transfer point for the periphery of the foam component, making it less likely for the foam component to move laterally within the accommodating cavity. At the same time, a gap is formed between the periphery of the foam component and the concave part of the arc segment, which provides allowance for the inward and outward bending of the arc segment under pressure and for the local deformation of the periphery of the foam component. Thus, the foam component is effectively limited by the side of the outer shell, but is not rigidly clamped by the entire surface of the side wall of the accommodating cavity, which helps to reduce the shear concentration on the periphery of the foam component and makes the outer shell and the foam component form a more continuous buffer fit on the periphery of the accommodating cavity.

[0016] In the composite cushioning structure for shoe soles disclosed in at least one embodiment, preferably, the curvature of the arc segment is 1 / 2 to 1, and the curvature is a dimensionless parameter characterizing the degree of bending of the arc segment relative to a corresponding circular arc reference.

[0017] In the above design, curvature limits the bending performance of the arc segment. If the curvature is too small, the arc segment tends to be nearly straight, resulting in insufficient bending clearance of the cushioning unit during the initial impact phase. If the curvature is too large, the sidewalls may bulge excessively outward or inward, reducing the lateral stacking stability of the cushioning unit. Limiting the curvature to 1 / 2 to 1 helps to achieve a balance between initial energy absorption and support stability, allowing the air cushion layer to form a more stable superimposed buffer with the central foam component.

[0018] In the composite cushioning structure for shoe soles disclosed in at least one embodiment, preferably, a plurality of cushioning units located around the accommodating cavity and in the outer region of the air cushion layer are arranged in a row along a first transverse direction and in a column along a second transverse direction, wherein the first direction is perpendicular to the second direction.

[0019] In the above design, the cushioning units are arranged in rows and columns along two lateral directions, so that the periphery of the accommodating cavity and the outer area of ​​the air cushion layer both have repeatable pressure-bearing units. This arrangement facilitates the formation of a relatively uniform cushioning structure in local areas of the sole, and also makes it easy to adjust the coverage of the cushioning units according to the force requirements of the heel or forefoot.

[0020] In the composite cushioning structure for shoe soles disclosed in at least one embodiment, preferably, in two adjacent cushioning units in the first direction, the portion of the outer sidewall of one cushioning unit intersecting with a vertical section passing through its longitudinal axis and parallel to the first direction is in contact with the corresponding portion of the outer sidewall of the other cushioning unit from top to bottom; in two adjacent cushioning units in the second direction, the portion of the outer sidewall of one cushioning unit intersecting with a vertical section passing through its longitudinal axis and parallel to the second direction is in contact with the corresponding portion of the outer sidewall of the other cushioning unit from top to bottom.

[0021] In the above design, the damping unit forms a top-to-bottom fit in both the first and second directions. This fit extends the lateral support path along the thickness of the outer shell, allowing the air cushion layer to maintain its integrity under multi-directional stress. Consequently, the outer shell forms a relatively stable pressure-bearing frame around the foam component, which helps the foam component maintain its central position within the cavity and stably participate in subsequent compression.

[0022] At least one embodiment discloses a method for preparing a composite cushioning structure for shoe soles. The method is used to prepare the composite cushioning structure for shoe soles described in any of the foregoing embodiments. The method includes: Step 1, establishing a 3D printed model of the cushioning area of ​​the shoe sole, and setting an outer cover layer, an air cushion layer, multiple cushioning units, and a cavity for accommodating a foam component in the 3D printed model; Step 2, printing according to the 3D printed model to form the lower structure of the outer shell, and forming part of the cushioning units and the bottom and peripheral boundaries of the cavity; Step 3, pausing printing after the cavity reaches a preset height, and placing the foam component into the cavity; Step 4, after confirming that the foam component is in place, raising the print head and resuming printing; Step 5, continuing to print the upper structure of the outer shell and the remaining cushioning units above the foam component; wherein, the ejection temperature of the printing material is suitable for softening or partially melting the surface of the foam component and forming a thermally melted bonding interface with the continuously deposited printing material.

[0023] In the above method, the foam component is placed into the receiving cavity during the shell printing process, rather than being inserted after the shell is fully formed. Pausing printing after the receiving cavity reaches a preset height allows the bottom and peripheral boundaries of the cavity to form first, providing an accurate placement position for the foam component. Raising the print head and resuming printing after confirming the foam component is in place reduces the possibility of collision between the print head and the foam component. Continuing to print to form the upper shell structure and remaining damping units, the heat from the printing material softens or partially melts the surface of the foam component, forming a thermally bonded interface. This preparation method allows the foam component to be stably placed inside the shell and forms a stable connection with it, while also facilitating the fabrication of the composite damping structure.

[0024] In the preparation method disclosed in at least one embodiment, preferably, a thermoplastic elastic material is used for melt extrusion 3D printing, the nozzle temperature is 230°C to 250°C, the speed of the first layer of recovery printing is less than 30 mm / s, and the flow rate of the first layer of recovery printing is increased by 5% to 10% compared with the conventional printing flow rate.

[0025] In the above design, a nozzle temperature of 230°C to 250°C is conducive to the stable deposition of thermoplastic elastomer materials and also to the moderate softening or local melting of the foam surface. When the initial printing speed is low and the flow rate is increased relative to the conventional printing flow rate, the continuing deposition of printing material can more fully contact the foam surface, thereby improving the continuity and stability of the thermal fusion bonding interface.

[0026] In at least one embodiment, a sole is disclosed, wherein the sole employs a composite cushioning structure for soles as described in any of the foregoing embodiments as at least a part of the sole.

[0027] In the aforementioned sole, the composite cushioning structure can be placed in the heel strike area or the forefoot strike area, or in other areas requiring cushioning retention. The air cushion layer in the outer shell first absorbs energy through bending of the cushioning unit, and the foam component set in the accommodating cavity then participates in the subsequent compression in a controlled manner. This helps to improve the cushioning performance of the sole while maintaining lightweight design, and improves cushioning retention after fatigue. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the following description of the embodiments are briefly introduced. Obviously, the accompanying drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0029] Figure 1 This is an overall schematic diagram of the composite damping structure involved in Embodiment 1 of the present invention; Figure 2 for Figure 1 A schematic diagram of the composite shock-absorbing structure after the removal of the overlying layer; Figure 3 for Figure 1 A schematic diagram of a half-section of a composite shock-absorbing structure; Figure 4 for Figure 1 A schematic diagram of the vertical cross-section of the damping unit in the air cushion layer of the composite damping structure; Figure 5 This is a schematic diagram of the vertical cross-section of the damping unit in the air cushion layer of the composite damping structure involved in Embodiment 2 of the present invention; Figure 6 This is a schematic diagram of the vertical cross-section of the damping unit in the air cushion layer of the composite damping structure involved in Embodiment 3 of the present invention.

[0030] Explanation of key figure labels: Upper cover 10; lower cover 20; air cushion layer 30; shock absorption unit 31; curved segment 311; straight segment 312; air chamber 32; protrusion 33; contraction section 34; accommodating cavity 35; foaming component 40. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are preferred embodiments of the present invention and should not be considered as excluding other embodiments. Other implementation methods obtained by those skilled in the art based on the embodiments of the present invention without creative effort should also fall within the scope of protection of the present invention.

[0032] In the claims and description of this invention, unless otherwise expressly defined, the terms "first," "second," etc., are used only to distinguish different objects and not to limit the order. The terms "upper," "lower," "inner," "outer," "front," "rear," "lateral," and "vertical," etc., are used to describe the relative positions between the various structures based on the usage state of the sole and the schematic relationship in the drawings, and should not be construed as requiring the product to maintain a certain absolute orientation during manufacturing, transportation, or use.

[0033] Example 1 This embodiment provides a shoe sole. The sole has a forefoot area and a heel area, with the heel area bearing a larger impact load upon the wearer's landing. In this embodiment, the heel area of ​​the sole is provided with a composite cushioning structure. This composite cushioning structure can be located in the center of the heel area, or it can extend inwards or outwards according to the sole's contour. The portion of the sole outside the heel area can be made of conventional foam materials or a rubber outsole; this invention does not limit this.

[0034] like Figure 1 As shown, Figure 1The overall morphology of the composite cushioning structure is shown. The composite cushioning structure includes an outer shell and a foam component. The outer shell has an outer covering layer and an air cushion layer. The outer covering layer includes an upper covering layer and a lower covering layer, with the upper covering layer located above the air cushion layer and the lower covering layer located below the air cushion layer. The air cushion layer, sandwiched between the upper and lower covering layers, is used to generate structural deformation during the initial impact phase, thereby reducing the peak load transmitted to the foam component. The upper covering layer is used to absorb pressure from the foot side and distribute the pressure to multiple cushioning units within the air cushion layer; the lower covering layer is used to provide continuous support for the air cushion layer and serves as a support boundary at the lower end of the cushioning units.

[0035] like Figure 2 As shown, Figure 2 The diagram illustrates the distribution of the air cushion layer after the top cover layer has been removed. With the top cover layer removed, the lateral stacking of the multiple damping units can be observed from above, with the bottom cover layer located beneath the air cushion layer and supporting each damping unit. This figure corresponds to an implementation where the outer cover layer includes both the top and bottom covers.

[0036] like Figure 3 As shown, Figure 3 The half-section of the composite damping structure is shown. Figure 3 In another corresponding embodiment, the outer covering layer may further include a side covering layer located on the outer periphery of the air cushion layer and connecting the upper and lower covering layers to cover at least part of the damping unit from the side. That is, in this embodiment, the outer covering layer may form a cover only on the upper and lower sides of the air cushion layer, or it may further form a lateral cover on the basis of the upper and lower side covers. Both of the above embodiments can be used in the composite damping structure of this embodiment.

[0037] In this embodiment, the outer shell is integrally formed by melt extrusion 3D printing. The upper and lower covering layers can be made of the same thermoplastic elastic material as the air cushion layer, or they can be made of different hardnesses depending on the stress requirements of the sole. For example, the upper covering layer can be made of a more elastic material to improve the feel on the side closer to the foot, while the lower covering layer can be made of a more rigid material to improve the support stability on the grounding side. The material of the air cushion layer can also be different from that of the upper or lower covering layer, as long as it can form a stable connection with both and create the required sealing relationship at the upper and lower ends of the cushioning unit.

[0038] The outer shell can be printed using thermoplastic elastomers, such as Pebax or aliphatic TPU. In one specific sample, the outer shell was printed using Pebax 3533, with an overall vertical dimension of 20mm. The foam component is made of nitrogen-foamed thermoplastic elastomer sheet, 7mm thick, with a density of approximately 0.10g / cm³, and is located in the middle of the shell's vertical dimension. Therefore, the vertical dimension of the foam component accounts for approximately 35% of the shell's vertical dimension, falling within the range of 25% to 40%.

[0039] The cushioning layer comprises several cushioning units. These units are stacked laterally, which can include the length and width of the sole. Each cushioning unit is formed by sidewalls surrounding its perimeter and arranged around a vertically extending longitudinal axis. From a top-down view, the cushioning unit can be nearly circular, elliptical, or have a ring-shaped profile that facilitates stacking. The unit of revolution here does not require it to be a mathematically perfect cylinder, as long as its sidewalls form a circumferential structure around the longitudinal axis capable of withstanding vertical loads.

[0040] like Figure 4 As shown, Figure 4 The diagram illustrates the sidewall profile of the damping element in a vertical section. The sidewall of the damping element forms several arc segments from top to bottom on the vertical section passing through its longitudinal axis. Some arc segments extend from top to bottom towards the outer side of the damping element, while others extend from top to bottom towards the inner side, with vertically adjacent arc segments smoothly connected. Outward and inward extensions are relative to the longitudinal axis of the damping element, indicating that the sidewall is moving away from or closer to the longitudinal axis on the vertical section. Smooth connection means that adjacent arc segments transition with a continuous curved surface, without forming sharp corners, right-angle steps, or abrupt angles. In this way, when the damping element is compressed, the sidewall can undergo recoverable bending along a continuous arc path.

[0041] The cushioning unit in this embodiment can be a closed or nearly closed unit. Located outside the accommodating cavity, the upper end of the cushioning unit can be connected to the upper cover layer, and the lower end can be connected to the lower cover layer, creating an air chamber inside the corresponding cushioning unit. This connection can be a continuous joint formed by integral printing, or a joint that remains airtight or nearly airtight after molding. When the sole is impacted, the upper cover layer first distributes the pressure to multiple cushioning units, and the sidewalls of the cushioning units then bend along an arc segment, changing the volume of the air chambers accordingly. During this process, the lower cover layer restricts excessive outward expansion of the lower end of the cushioning unit and provides overall support for the air cushion layer. This structure can absorb a portion of the impact energy before the foam components participate in the subsequent compression.

[0042] The curvature of the arc segment can range from 1 / 2 to 1. Curvature is a dimensionless parameter characterizing the degree of bending of the arc segment relative to the corresponding circular arc reference. In actual modeling, the corresponding circular arc reference can be determined in the vertical section of the damping element, and then the curvature of the arc segment can be set according to the degree of bending of the arc segment relative to this circular arc reference. When the curvature is between 1 / 2 and 1, the arc segment can provide recoverable bending deformation without making the damping element as a whole too soft. The curvature of different damping elements can be the same, or it can be locally adjusted according to the stress requirements of different locations in the heel area.

[0043] Multiple cushioning units located around the accommodating cavity and the outer area of ​​the air cushion layer can be arranged in rows along a first transverse direction and in columns along a second transverse direction, with the first direction perpendicular to the second direction. For the sole, the first direction roughly corresponds to the length of the sole, and the second direction roughly corresponds to the width of the sole. In a 100mm*100mm*20mm heel counter, the cushioning units can be densely arranged in multiple rows and columns, with a maximum number of approximately 1024 units. Some cushioning units at the edge of the sole can be cut or reduced in size according to the shape of the sole.

[0044] In two laterally adjacent damping units, the sidewall portion containing the outward-extending arc segment of one damping unit can be opposite the sidewall portion containing the inward-extending arc segment of the other damping unit within the same vertical height range. The outer surfaces of the two opposite sidewalls are at least partially in contact. This contact can be surface contact or a contact zone formed along a local arc surface. Through this contact relationship, multiple damping units can share the impact load in the heel region, reducing the risk of local outward expansion or local collapse of a single damping unit.

[0045] In this embodiment, a portion of the damping units enclose a receiving cavity. The receiving cavity is located in the rear region of the outer shell and can be situated within the internal space enclosed by multiple damping units. The receiving cavity has a lateral inner wall, a top wall, and a bottom wall. The lateral inner wall is formed by the side walls of the damping units surrounding the receiving cavity, the top wall can be formed by a corresponding portion of the upper cover layer, and the bottom wall can be formed by a corresponding portion of the lower cover layer. That is, the upper and lower cover layers not only cover the damping units outside the receiving cavity but also form vertical restraining surfaces for the foamed component at the location of the receiving cavity. The receiving cavity does not need to be a completely airtight cavity; it only needs to be able to accommodate the foamed component and provide relative circumferential and vertical constraints on the foamed component through its inner wall.

[0046] The foam component is housed within the receiving cavity. In a top-view view, the foam component conforms to the contour of the receiving cavity, with its periphery facing the inner lateral wall, its upper side facing the top wall, and its lower side facing the bottom wall. The foam component is located in the vertical center of the outer shell, meaning that air cushion layers are retained above and below the foam component, preventing it from being offset near the upper or lower surface of the outer shell. In actual products, the geometric center of the foam component can roughly correspond to the vertical center of the outer shell, or it can have a small deviation without compromising the upper and lower cushioning allowances.

[0047] In one specific structure, the inner side wall of the accommodating cavity is formed by an arc segment corresponding to the damping unit. The arc segment has a protruding portion relative to the inner side of the accommodating cavity in its vertical cross-section, and also a recessed portion that recedes outward relative to the protruding portion. The periphery of the foam component connects to the protruding portion of the corresponding arc segment, which provides local positioning and support for the foam component; a gap is formed between the periphery of the foam component and the recessed portion of the arc segment, thus preventing full-surface compression on the periphery of the foam component. In this way, the foam component is effectively confined by the side of the outer shell while also having adequate deformation space.

[0048] Under the aforementioned positional relationship, upon impact with the heel, the outer cladding and air cushion layer of the shell, closest to the impact side, are compressed first. The curved sidewalls of the cushioning unit undergo restorative bending, allowing the shell to absorb some of the impact energy initially. Subsequently, the load is transferred to the foam component located in the middle of the shell, where it is compressed in a controlled manner within its accommodating cavity. The shell structure remains above and below the foam component, thus the foam component does not become a separately exposed pressure-bearing layer but rather forms a phased buffer together with the shell.

[0049] A heat-melt bonding interface is formed between the foam and at least a portion of the inner wall of the accommodating cavity. This heat-melt bonding interface can be located between the upper side of the foam and the top wall, between the peripheral side of the foam and the lateral inner wall, or between the lower side of the foam and the bottom wall. This interface is formed by the bonding of the outer shell printing material with softened or partially melted areas on the surface of the foam during continued deposition. The heat-melt bonding interface does not require the entire surface of the foam to be melted, nor does it require the formation of a weld layer of uniform thickness. As long as a stable bond is formed between the foam and the inner wall of the accommodating cavity in at least a portion of the area, the possibility of the foam slipping or detaching from the outer shell during repeated compression can be reduced.

[0050] This embodiment also provides a method for preparing the aforementioned composite cushioning structure. During preparation, a 3D printed model of the heel area of ​​the shoe sole is first established. An outer layer and an air cushion layer are set in this model, and multiple cushioning units are set within the air cushion layer. The model also includes a receiving cavity for accommodating the foam component, the position of which corresponds to the location in the heel area where enhanced cushioning is required. During modeling, the curved section of the inner wall of the receiving cavity can also be made to form a local mating relationship with the periphery of the foam component.

[0051] After the model is built, printing is carried out according to the 3D printing model. During printing, the lower structure of the shell is formed first, along with some cushioning units and the bottom and peripheral boundaries of the receiving cavity. Printing is paused once the receiving cavity reaches the preset height, and the foam part is placed into the receiving cavity. The preset height can be determined based on the vertical dimensions of the foam part, the position of the bottom wall of the receiving cavity, and the subsequent printing thickness of the upper structure. The foam part can be placed manually or by an automated loading and unloading device.

[0052] Once the foam component is confirmed to be in place, the print head is raised and printing resumes. Confirmation of placement can be achieved through visual recognition, laser ranging, limit detection, or other conventional positioning methods. Raising the print head prevents the nozzles from colliding with the foam component during resumed printing. After resuming printing, the upper structure of the outer shell and the remaining cushioning units continue printing above the foam component, ensuring the foam component remains within the receiving cavity and is positioned vertically in the middle of the outer shell.

[0053] In one specific preparation method, the nozzle temperature is 230°C to 250°C. The initial print speed is less than 30 mm / s, and the initial print flow rate is increased by 5% to 10% compared to the conventional print flow rate. The lower initial print speed prolongs the contact time between the ejected material and the surface of the foam, while the increased flow rate helps to fill the tiny gaps between the surface of the foam and the inner wall of the shell, thereby improving the continuity of the thermally melted bonding interface.

[0054] Example 2 The difference between this embodiment and Embodiment 1 is that a short straight segment is added between the ends of the two arc segments on the sidewall of the damping unit. The rest of the structure, materials and preparation method can be the same as in Embodiment 1.

[0055] like Figure 5 As shown, on the vertical section along the longitudinal axis of the damping element, the straight segment lies between two vertically adjacent arc segments. The upper end of the straight segment smoothly transitions to the arc segment above it, and the lower end of the straight segment smoothly transitions to the arc segment below it. This straight segment can extend vertically or have a small angle of inclination relative to the vertical. In a specific sample, the length of the straight segment can be from 0.5 mm to 1.5 mm, and does not exceed 30% of the vertical pitch of the adjacent arc segments.

[0056] Compared to Example 1, this short straight segment reduces bending concentration at the direct junction of adjacent curved segments, allowing the damping unit to absorb energy through the deformation of the curved segments during the initial compression phase, while also exhibiting higher support stability during the middle and later compression phases. The shorter length of the straight segment prevents the damping unit from becoming a structure primarily supported by straight walls, and also avoids disrupting the main buffer path for the continuous deformation of the curved segments.

[0057] Example 3 The difference between this embodiment and Embodiment 1 is that a long straight section is provided below the side wall of the damping unit, while the rest of the structure, materials and preparation method can be the same as in Embodiment 1.

[0058] like Figure 6As shown, the sidewall of the damping unit forms a straight segment below all the curved segments. The lower end of this straight segment connects to the lower cover layer in the outer cover, and the upper end smoothly connects to the lowermost curved segment. In a specific sample, the overall vertical dimension of the shell is 20 mm, the foam thickness is 7 mm, and the length of the straight segment below all the curved segments can be 3 mm to 6 mm. A rounded corner or continuous curved surface transition is used between the straight segment and the lowermost curved segment to avoid stress concentration at their junction.

[0059] The longer straight segment can serve as a support foundation for the shock-absorbing unit near the ground, providing a more stable lower boundary for the unit when it is subjected to ground pressure in the heel area. Compared to Embodiment 1, this embodiment is more suitable for placement on the outer or inner side of the heel, or other locations requiring reinforced support. Under pressure, the lower straight segment provides stable support first, while the upper curved segment then undergoes a recoverable bend, thus balancing ground support and cushioning deformation.

[0060] Comparative Example 1 To illustrate the difference in performance between Example 1 and a single cushioning unit structure and a single foam structure, heel cushioning test pieces with different structural forms but the same application location were prepared for comparative evaluation. During the evaluation, the focus was on observing the transmission of impact upon landing, cushioning retention after repeated compression, and recovery after compression.

[0061] The sample in Example 1 uses the composite shock-absorbing structure of the present invention. The outer shell of the sample is printed from thermoplastic elastomer material, the air cushion layer includes arc-shaped sidewall shock-absorbing units, and the foam is a nitrogen-foamed thermoplastic elastomer sheet located in the middle of the vertical direction of the outer shell.

[0062] The first control sample was a sole specimen entirely composed of cushioning units. This specimen did not contain any foam components; the heel area relied entirely on the printed, stacked cushioning units to absorb impact. The second control sample was a sole specimen entirely composed of foam components. This specimen did not contain an outer shell or air cushion layer; the heel area primarily relied on the compression of the foam material itself to absorb impact.

[0063] The comparative results show that Example 1 outperforms the aforementioned single structure in terms of initial cushioning, cushioning retention after repeated compression, and compression recovery. While soles using only cushioning units can generate initial deformation through the curved sidewalls, the lack of a centrally located foam component to participate in subsequent compression makes them more prone to localized deformation concentration after repeated compression. Soles using only foam components have a softer initial feel, but the foam material alone bears the impact, resulting in poor thickness retention and support stability after long-term compression. The composite cushioning structure of this invention allows the cushioning units to absorb energy through bending first, followed by controlled compression of the foam component, and maintains a stable fit between the two through a heat-fused bonding interface, thus achieving better overall cushioning performance.

[0064] The above description of the embodiments and comparative examples is used to explain the scope of protection of the present invention, but does not constitute a limitation on the scope of protection of the present invention. Through the teachings of the present invention or the above embodiments, those skilled in the art, in conjunction with common general knowledge and ordinary technical knowledge and / or existing technology, can obtain modifications and equivalent substitutions to the embodiments of the present invention or some of its technical features, and can also obtain other improvements, through logical analysis and reasoning, or through limited experimentation. All of these should be included within the scope of protection of the present invention.

Claims

1. A composite cushioning structure for shoe soles, characterized in that, include: The outer shell has an outer covering layer and an air cushion layer; The air cushion layer includes a plurality of shock-absorbing units stacked laterally; each shock-absorbing unit is a body of revolution formed by sidewalls surrounding its periphery and extending about a vertically extending longitudinal axis, wherein its sidewalls form a plurality of alternating outward and inward extending arc segments on a vertical cross-section passing through its longitudinal axis, and adjacent vertically adjacent arc segments are smoothly connected; a portion of the shock-absorbing units encloses a receiving cavity, the receiving cavity having a lateral inner wall formed by the sidewalls of the shock-absorbing units, and a top wall and a bottom wall respectively sealing the upper and lower ends of the corresponding shock-absorbing units; the outer covering layer seals the upper and / or lower ends of the shock-absorbing units located outside the receiving cavity; and A foamed component is housed in the accommodating cavity, wherein the peripheral side, upper side, and lower side of the foamed component are respectively opposite to the lateral inner wall, top wall, and bottom wall, and form a heat-melt bonding interface with at least a portion of the inner wall of the accommodating cavity. The vertical dimension of the foam component is 25% to 40% of the vertical dimension of the outer shell, and the foam component is located at the middle position of the vertical direction of the outer shell.

2. The composite cushioning structure for shoe soles as described in claim 1, characterized in that, In two horizontally adjacent damping units, the sidewall portion of the outwardly extending arc segment of one damping unit is opposite to the sidewall portion of the inwardly extending arc segment of the other damping unit within the same vertical height range, and the outer wall surfaces of the sidewalls of the two adjacent damping units are at least partially in contact within the same vertical height range.

3. The composite cushioning structure for shoe soles as described in claim 1, characterized in that, The outer covering includes a lower covering portion located below the air cushion layer; at least a portion of the damping units form a straight segment below all the arc segments, the lower end of the straight segment is connected to the lower covering portion, and the upper end of the straight segment is smoothly connected to the lowermost arc segment.

4. The composite cushioning structure for shoe soles as described in claim 3, characterized in that, The inner side wall of the accommodating cavity is formed by the arc segment portion of the corresponding damping unit; the periphery of the foaming element is connected to the protruding portion of the arc segment of the corresponding damping unit to form a gap with the concave portion of the arc segment.

5. The composite cushioning structure for shoe soles as described in claim 1, characterized in that, The curvature of the arc segment is between 1 / 2 and 1, and the curvature is a dimensionless parameter characterizing the degree of bending of the arc segment relative to the corresponding circular arc reference.

6. The composite cushioning structure for shoe soles as described in claim 1, characterized in that, Multiple damping units located around the accommodating cavity and the outer region of the air cushion layer are arranged in rows along a first transverse direction and in columns along a second transverse direction, wherein the first direction is perpendicular to the second direction.

7. The composite cushioning structure for shoe soles as described in claim 6, characterized in that, in In two adjacent damping units in the first direction, the portion of the outer sidewall of one damping unit intersecting with a vertical section passing through its longitudinal axis and parallel to the first direction is in contact with the corresponding portion of the outer sidewall of the other damping unit from top to bottom; in two adjacent damping units in the second direction, the portion of the outer sidewall of one damping unit intersecting with a vertical section passing through its longitudinal axis and parallel to the second direction is in contact with the corresponding portion of the outer sidewall of the other damping unit from top to bottom.

8. A method for preparing a composite cushioning structure for shoe soles, characterized in that, The method for preparing the composite cushioning structure for shoe soles as described in any one of claims 1 to 7 comprises: A 3D printed model of the cushioning area of ​​the shoe sole is established, and an outer cover, an air cushion layer, multiple cushioning units, and a cavity for accommodating the foam component are set in the 3D printed model. The 3D printing model is printed to form the lower structure of the outer shell, and to form part of the shock-absorbing unit and the bottom and peripheral boundaries of the accommodating cavity; Printing is paused once the cavity reaches a preset height, and the foamed part is placed into the cavity. After confirming that the foaming component is in place, lift the print head and resume printing; Continue printing the upper structure of the housing and the remaining damping units above the foam component; The ejection temperature of the printing material is suitable for softening or partially melting the surface of the foamed part, and forming a thermally melted bonding interface with the continuing to deposit printing material.

9. The preparation method according to claim 8, characterized in that, Thermoplastic elastic materials are used for melt extrusion 3D printing, with a nozzle temperature of 230°C to 250°C; the speed of the first layer of recovery printing is less than 30 mm / s, and the flow rate of the first layer of recovery printing is increased by 5% to 10% compared with the conventional printing flow rate.

10. A shoe sole, characterized in that, It employs a composite cushioning structure for the sole as described in any one of claims 1 to 7 as at least a part of the sole.

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