FR3147134A1 - Sports article produced using an additive manufacturing process and method of manufacturing such an article - Google Patents

Abstract

The present invention relates to a sports article comprising an element (1) produced by means of an additive manufacturing method, the element (1) comprising: an external structure (10); an internal structure (12), forming a three-dimensional lattice structure formed by the repetition of at least one elementary pattern; an intermediate structure (14), the intermediate structure (14) ensuring the junction between the external structure (10) and the internal structure (12). Figure 2

Description

Sports article produced using an additive manufacturing process and method of manufacturing such an article

The present application relates to a sports article comprising at least one part produced by means of an additive manufacturing process. The present application also relates to a footwear article, such as a sports shoe, comprising such a sole. A sports article is for example a shoe sole (outer sole, including a midsole and/or a wear sole), body protection (knee pad, elbow pad, back protection, etc.), a helmet, a saddle, a child seat adaptable to a bicycle.

Additive manufacturing processes, such as 3D printing, have many advantages, including the ability to produce objects with varied and complex shapes, and in particular shapes that are difficult or impossible to produce using conventional processes. When it is desired to produce, using an additive manufacturing process, an object with a particular mechanical behavior, and in particular a mechanical behavior requiring a high level of elasticity, it is known to produce at least part of such an object in the form of a three-dimensional lattice structure, or lattice structure. In such a structure, the combination of solid areas and empty areas, combined with the use of a material with suitable properties, makes it possible to obtain varied mechanical behaviors, without penalizing the mass of the assembly. A lattice structure that must have homogeneous mechanical properties is generally produced by repeating an elementary pattern, this pattern repeating itself according to the longitudinal, transverse and thickness dimensions of the object. However, the constraints leading to the design of a lattice structure may lead to the visual appearance of the outer surface thereof not being aesthetic, or in any case, not leaving enough freedom in the design of this outer surface, under penalty of altering the mechanical properties of the lattice structure. The aim of the present invention is to provide an element produced by means of an additive manufacturing method, the element comprising a lattice structure conferring given mechanical properties, and an outer surface whose visual appearance is independent of the lattice structure.

• une structure externe ;
• une structure interne, formant une structure tridimensionnelle en treillis formée par la répétition d’au moins un motif élémentaire ;
• une structure intermédiaire, la structure intermédiaire assurant la jonction entre la structure externe et la structure interne.

For this purpose, the invention relates to a sports article comprising an element produced using an additive manufacturing process, the element comprising:

• an external structure;
• an internal structure, forming a three-dimensional lattice structure formed by the repetition of at least one elementary pattern;
• an intermediate structure, the intermediate structure providing the junction between the external structure and the internal structure.

Thus, by providing an external structure forming the outer surface of the element, the external structure being connected to the internal structure by an intermediate structure, it is possible to make the design of the external structure and the design of the internal structure entirely independent. It thus becomes possible to maintain the mechanical and functional integrity of the internal structure, while defining the external structure according to the desired criteria, and in particular according to the desired visual appearance.

According to other characteristics of the invention, the sports article according to the invention comprises one or more of the following optional characteristics, considered alone or in all possible combinations:

In one embodiment, the intermediate structure comprises connecting beams, each connecting beam connecting a node of an elementary pattern to the external structure.

In one embodiment, the external structure is formed at least in part by a three-dimensional lattice structure comprising beams connected by nodes, each connecting beam of the intermediate structure being connected either to a node of the external structure or to a solid part.

In one embodiment, for each connecting beam connected to a node of the external structure, the connecting beam is connected to this node according to a distance criterion between the node of the internal structure and the node of the external structure.

In one embodiment, a connecting beam connected to a node of the internal structure is connected to the nearest node of the external structure.

In one embodiment, a connecting beam connected to a node of the internal structure is connected to a node located at a distance included in a predetermined distance range, so as to respect at least one additional criterion, such as an angle between the connecting beam and the external structure at the connection.

• déterminer une structure externe de l’élément ;
• déterminer la structure interne inscrite dans le volume interne délimité par la structure externe, la structure interne étant réduite par rapport à ce volume interne de façon à respecter au moins un critère relatif au troncage d’au moins une partie des motifs élémentaires constituant la structure interne ;
• déterminer une structure intermédiaire assurant la jonction entre la structure interne et la structure externe ;
• réaliser l’élément au moyen d’un procédé de fabrication additive.

The invention also relates to a method of manufacturing a sports article as defined above, the method comprising the steps of:

• determine an external structure of the element;
• determine the internal structure inscribed in the internal volume delimited by the external structure, the internal structure being reduced in relation to this internal volume so as to respect at least one criterion relating to the truncation of at least part of the elementary patterns constituting the internal structure;
• determine an intermediate structure ensuring the junction between the internal structure and the external structure;
• produce the element using an additive manufacturing process.

In one embodiment, the step of determining the intermediate structure comprises a sub-step of determining elementary pattern nodes to be connected to the intermediate structure.

In one embodiment, the intermediate structure comprises connecting beams, each connecting beam connecting a node of an elementary pattern to the external structure.

In one embodiment, the external structure is formed at least in part by a three-dimensional lattice structure comprising beams connected by nodes, each connecting beam of the intermediate structure being connected either to a node of the external structure or to a solid part.

In one embodiment, for each connecting beam connected to a node of the external structure, the connecting beam is connected to this node according to a distance criterion between the node of the internal structure and the node of the external structure.

In one embodiment, a connecting beam is connected to the nearest node.

In one embodiment, a connecting beam is connected to a node located at a distance included in a predetermined distance range, so as to satisfy at least one additional criterion, such as an angle between the connecting beam and the external structure at the connection.

In one embodiment, the criterion relating to the truncation of the elementary patterns is a criterion defining a maximum degree of truncation of the elementary patterns.

In one embodiment, the criterion is set so that no elementary pattern is truncated, or so that the maximum degree of truncation is less than or equal to 30%.

Other features and advantages of the present invention will appear on reading the description which follows and on examining the appended figures in which:

there is a perspective view of an element produced using an additive manufacturing process in accordance with the invention;

there is a cross-sectional view of the element of the ;

there is a perspective view of the element of the ;

there is a detailed view of the ;

there is a schematic view of an elementary vinyl type pattern;

there is a schematic view showing the internal structure of the with a non-homogeneous repetition of the elementary pattern;

there is a perspective view of a sports shoe midsole made in accordance with the invention;

there is a sectional view of the sole of the ;

there is a diagram representing the steps of a manufacturing process in accordance with the invention.

Figures 1 to 4 illustrate an element 1 according to the invention, in the example a block produced by means of a manufacturing method according to the invention, and intended to constitute a sports article or to form a part of a sports article. The sports article may be for example a shoe sole (outer sole, including a midsole and/or a wear sole), body protection (knee pad, elbow pad, back protection, etc.), a helmet, a saddle, a child seat adaptable to a bicycle, etc.

Element 1 is in the example a block of generally cubic shape, which can for example serve as a constituent element of body protection such as a knee pad suitable for the practice of a sport such as volleyball. shows element 1 in perspective. In this figure, only the external surface of element 1 is visible, consisting of an external structure 10, or external skin 10.

Figures 2 to 4 show element 1 of the seen in section.

• une structure externe10, ou peau externe 10 ;
• une structure interne 12, ou structure fonctionnelle 12 ;
• une structure intermédiaire 14, ou structure de liaison 14, assurant la jonction entre la structure externe 10 et la structure fonctionnelle 12.

There is a perspective view of element 1 in cross-section, that is to say in section in a plane parallel to the XY plane of the . There is a partial view analogous to the , element 1 being seen in perspective. The is a detailed view of the . As visible on the at 4, element 1 comprises three interrelated structures:

• an external structure10, or external skin 10;
• an internal structure 12, or functional structure 12;
• an intermediate structure 14, or connecting structure 14, providing the junction between the external structure 10 and the functional structure 12.

The three structures 10, 12, 14 are obtained jointly by means of an additive manufacturing process. The boundary between the intermediate structure 14 and the internal structure 12 is materialized in FIGS. 2 to 4 by the dotted line L. The boundary between the external structure 10 and the intermediate structure 14 is materialized on the by the dotted line M.

The internal structure 12 is formed by a three-dimensional lattice structure, i.e. a lattice-type structure. Thus, the internal structure 12 is formed by the repetition, along each of the longitudinal X, transverse Y and thickness Z directions of the element 1, of elementary patterns 120 which are described in more detail below. The structure of the elementary patterns 120, and the way in which they are repeated along the three directions X, Y, Z of the element 1 confer physical and mechanical properties to the internal structure 12, such as, for example, properties of resistance and elasticity, and, in particular, properties of damping and restitution of energy in the event of deformation.

The outer skin 10, or outer structure, forms the outer surface of the element 1. The outer structure 10 is in the example formed by a three-dimensional lattice structure, formed partly by the repetition of elementary patterns, but not only. The outer structure 10 is the only structure of the element 1 that is entirely visible and is in particular intended to give the element 1 the desired visual appearance.

The intermediate structure 14, or connecting structure, provides the junction between the external structure 10 and the internal structure 12. The intermediate structure 14 is in the example a three-dimensional lattice structure, comprising connecting beams 140. Providing an intermediate structure 14 makes it possible to provide a junction between the internal structure 12 and the external structure 10, this junction respecting, on the one hand, the mechanical behavior specific to the internal structure 12, and, on the other hand, the desired visual appearance of the external structure 10. Providing such an intermediate structure 14 makes it possible in particular to avoid the alteration, or at least too significant an alteration, of the elementary patterns 120 which would be located at the interface between the internal structure 12 and the external structure 10 in the absence of an intermediate structure. Indeed, the absence of a connecting structure could require truncating a significant portion of many elementary patterns, and thus alter the overall mechanical behavior of the internal structure 12. The intermediate structure 14 also makes it possible to avoid excessively large aggregates of material that could harm the mechanical behavior of the internal structure 12. Preferably, the intermediate structure 14 will be as thin as possible. The thickness of the intermediate structure 14, which will depend in particular on the dimensions of the element 1 and also on the size of the elementary patterns of the internal structure 12, will preferably be less than 10 mm, or less than 6 mm.

In the example, at least part of the internal structure 12 is formed by the repetition of an elementary pattern 120 of the vinyl type, this elementary pattern being represented in perspective on the . The use of this elementary pattern makes it possible to give the internal structure 12 the desired properties of elasticity, deformability, damping and durability in order to give the element 1 the desired mechanical behavior. The internal structure 12 may however be formed by a lattice structure comprising other elementary patterns or comprising several types of elementary patterns. In particular, the internal structure 12 may comprise zones formed by the repetition of different patterns, in order to give the element 1 damping properties, energy restitution and resistance which vary according to the zone considered, or according to other criteria. In a non-limiting manner, the following elementary patterns may be used: diamond pattern, octagonal pattern of the “edge” type, octagonal pattern of the “vertex” type, tetrahedral pattern, etc.

The mechanical characteristics of the lattice structure of the internal structure 12 can be adapted in particular by modifying parameters of the elementary pattern, among which are in particular the following parameters:

- size of the elementary pattern and number of repetitions on the axis considered (axes x, y, z visible on the ) ;

- the beam diameter, which is fixed mainly according to the desired rigidity for each beam: for example, it is between 0.5 and 5 mm, or between 1 and 3 mm;

- the size of the nodes, a node being defined as the intersection of at least two beams: the size of a node is for example between 100% and 130% of the diameter of the beams joining the node, or between 105% and 125%, or even between 110% and 120%;

- radius of curvature at the intersection between two or more beams: for example, it is between 1 and 5 mm, or between 2 and 3 mm. Preferably, the radius of curvature is such that it is equal to the beam diameter multiplied by a factor between 1 and 2, and for example equal to 1.5.

An elementary pattern 120 of type vintile is visible on the . This is an elementary three-dimensional structure, comprising a plurality of elementary structures 20 in the shape of a hexagon, each elementary structure 20 thus comprising six beams 22, some of these beams being common to at least two elementary structures. Nodes 24 connect two or more beams 22.

Like any elementary pattern, the elementary pattern of the vintile type can be modified by playing on several parameters, such as the size and the number of repetitions along each axis x, y and z, the beam diameter 22, the size of the nodes 24 or the radius of curvature at the intersection. The geometry based on hexagon shapes of this elementary pattern gives a lattice structure in particular a high capacity for shock absorption as well as good energy restitution. The elementary pattern of the vintile type can therefore be particularly suitable for the production of soles of sports shoes or absorption elements for personal protection such as knee pads.

In the example, the size of the elementary pattern 120 is 11 mm x 11 mm x 11 mm, which means that the elementary pattern 120 repeats within the internal structure 12 every 11 mm in each x, y, z direction.

There shows an exemplary embodiment of the internal structure 12 of the element 1 in which the beam diameter of the elementary patterns 120 increases progressively along the arrow F. For the same type of elementary pattern, increasing the beam diameter will increase the resistance of the internal structure 12, but will in return reduce its elasticity.

Figures 7 and 8 show a midsole 2 of a sports shoe according to the invention. The sole 2 comprises an external structure 10 forming in particular the covering of the sole, and an internal structure 12, visible in the , which represents the sole 2 seen in section. As for the element 1 of figures 1 to 4, the sole 2 comprises an intermediate structure 14 ensuring the junction between the internal structure 12 and the external structure 10.

The following is described, in particular in relation to the , a method according to the invention, making it possible to obtain sports articles including elements as described above.

Such a method comprises a step 200 during which an external structure 10 of the element 1 is determined. This structure is determined according to the external volume of the element to be produced, and according to the type of structure desired: the external structure can be solid, or form a three-dimensional lattice structure, comprising both solid parts and lattice parts.

The method then comprises a step 202 during which the internal structure 12 inscribed in the internal volume delimited by the external structure is determined, the internal structure being reduced relative to this internal volume so as to comply with at least one criterion representative of the integrity of at least part of the elementary patterns constituting the internal structure. This criterion may be, for example, a degree of truncation (average or maximum) permitted for all of the elementary patterns of the internal structure. For example, it may be imposed through this criterion that no elementary pattern be truncated. Alternatively, it may be imposed, for example, that no elementary pattern be truncated beyond a given degree of truncation. The degree of truncation may be expressed, for example, by a percentage giving the truncated volume relative to the initial volume of the elementary pattern. This value will be, for example, 30%, i.e. each elementary pattern will retain a volume after truncation greater than or equal to 70% of its initial volume.

The method then comprises a step 204 during which an intermediate structure 14 is determined, ensuring the junction between the internal structure and the external structure. This step makes it possible to determine the set of connecting beams 140 which will connect an elementary pattern of the internal structure to the external structure. Preferably, each connecting beam 140 will be connected to a node of an elementary pattern 120. The method will thus comprise a sub-step aimed at determining the set of nodes of elementary patterns to be connected to the connecting structure. The elementary patterns concerned are the elementary patterns forming the external surface of the internal structure 12. Among these elementary patterns, it is determined which nodes must be attached to the external structure, and therefore be connected to the intermediate structure. To discriminate these nodes, the following rule can be applied, for example: any node which is the intersection of less than three beams of the elementary pattern must be connected to the intermediate structure and therefore to a connecting beam 140. Thus, each node which must be connected to the external structure 10 will be connected to a connecting beam 140.

Each connecting beam 140 will further be connected to the external structure 10. If, near a connecting beam 140, the external structure 10 comprises a lattice part, therefore comprising beams 100 connected by nodes 102, the connecting beam 140 will be connected to a node 102. Thus, each connecting beam 140 will be connected either to a node or to a solid part of the external structure 10.

The definition of each connecting beam may obey one or more criteria. Among these criteria, a first distance criterion will be applied, that is to say that the choice of the connection location between a connecting beam 140 and the external skin 10 will be a function of the distance to the connection location between this connecting beam 140 and the internal structure. For example, it may be required that this distance be as short as possible. Or it may be required that it be the shortest possible distance by taking into account one or more additional criteria, such as for example the angle between the connecting beam and the external structure at the connection. It may also be possible to take into account size criteria (diameter, length, etc.) and shape criteria (for example that the connecting beam has a particular shape, such as a helical shape).

At the end of this stage, the intermediate structure is determined in such a way as to ensure the role of junction between the internal and external structures, in such a way as to best respect the functional integrity of the internal structure and thus optimize the mechanical behavior of the whole of the element 1 obtained.

The method then comprises the step 206 of producing the element 1, comprising the three structures determined as described above, by means of an additive manufacturing method. The element 1 may form the sports article as such, or form only a part thereof, in which case a step of assembling the element 1, for example to a support or to another element of the sports article, may be required.

Additional steps can be implemented after additive manufacturing. For example, a sandblasting step cleans and smooths the surface of the resulting element, which can be useful for improving the element's aesthetics and performance. A chemical smoothing step can also be implemented after additive manufacturing. This step improves the durability of the element, as well as its aesthetic appearance.

The method may be implemented with any type of suitable material, including thermoplastic materials, for example polymeric materials such as polyurethane, polyethylene, polypropylene, polystyrene, polycarbonate, acrylonitrile butadiene styrene, polyamide, polyethylene terephthalate, thermoplastic copolyamide, ether-amide block copolymer, etc.

The method according to the invention is suitable for producing sports articles which may include elements produced by additive manufacturing, such as for example: shoe soles (outer soles, including a midsole and/or a wear sole), body protection (knee pads, elbow pads, back protectors, etc.), helmets, bicycle saddles, a child seat adaptable to a bicycle, etc.

Claims (15)

Sports article comprising an element (1) produced using an additive manufacturing process, the element (1) comprising:

• an external structure (10);
• an internal structure (12), forming a three-dimensional lattice structure formed by the repetition of at least one elementary pattern;
• an intermediate structure (14), the intermediate structure (14) providing the junction between the external structure (10) and the internal structure (12).

Sports article according to the preceding claim, in which the intermediate structure (14) comprises connecting beams (140), each connecting beam (140) connecting a node (24) of an elementary pattern (120) to the external structure (10). Sports article according to the preceding claim, in which the external structure (10) is formed at least in part by a three-dimensional lattice structure comprising beams (100) connected by nodes (102), each connecting beam (140) of the intermediate structure (14) being connected either to a node (102) of the external structure (10), or to a solid part. Sports article according to the preceding claim, in which, for each connecting beam (140) connected to a node (102) of the external structure (10), the connecting beam (140) is connected to this node (102) according to a distance criterion between the node (120) of the internal structure (12) and the node (102) of the external structure (10). Sports article according to the preceding claim, in which a connecting beam (140) connected to a node (24) of the internal structure (12) is connected to the nearest node (102) of the external structure (10). A sporting article according to claim 4, wherein a connecting beam (140) connected to a node (24) of the internal structure (12) is connected to a node (102) located at a distance included in a predetermined distance range, so as to respect at least one additional criterion, such as an angle between the connecting beam (140) and the external structure (10) at the connection. Method for manufacturing a sports article comprising an element (1) intended to be produced using an additive manufacturing method according to one of the preceding claims, the method comprising the steps of:

• determine (200) an external structure (10) of the element (1);
• determine (202) the internal structure (12) inscribed in the internal volume delimited by the external structure, the internal structure being reduced in relation to this internal volume so as to respect at least one criterion relating to the truncation of at least part of the elementary patterns constituting the internal structure (12);
• determining (204) an intermediate structure (14) ensuring the junction between the internal structure and the external structure;
• producing (206) the element (1) by means of an additive manufacturing process.

Method according to the preceding claim, in which the step of determining (204) the intermediate structure (14) comprises a sub-step of determining nodes (24) of elementary patterns (120) to be connected to the intermediate structure (14). Method according to the preceding claim, in which the intermediate structure (14) comprises connecting beams (140), each connecting beam (140) connecting a node (24) of an elementary pattern (120) to the external structure (10). Method according to the preceding claim, in which the external structure (10) is formed at least in part by a three-dimensional lattice structure comprising beams (100) connected by nodes (102), each connecting beam (140) of the intermediate structure (14) being connected either to a node (102) of the external structure (10), or to a solid part. Method according to the preceding claim, in which, for each connecting beam (140) connected to a node (102) of the external structure (10), the connecting beam (140) is connected to this node (102) according to a distance criterion between the node (24) of the internal structure (12) and the node (102) of the external structure (10). Method according to the preceding claim, in which the connecting beam (140) is connected to the nearest node (102). The method of claim 11, wherein the connecting beam (140) is connected to a node (102) located at a distance included in a predetermined distance range, so as to respect at least one additional criterion, such as an angle between the connecting beam (140) and the external structure (10) at the connection. Method according to one of claims 7 to 13, in which the criterion relating to the truncation of the elementary patterns is a criterion defining a maximum degree of truncation of the elementary patterns. Method according to the preceding claim, in which the criterion is set so that no elementary pattern is truncated, or so that the maximum degree of truncation is less than or equal to 30%.