Mandrel for manufacturing a rotationally symmetrical part made of composite material
The mandrel design with actuation mechanisms and conical bearings addresses the challenges of radial stress and adhesion in composite part manufacturing, enabling stable formation and efficient removal of composite parts.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2025-09-02
- Publication Date
- 2026-03-19
AI Technical Summary
Existing mandrels for manufacturing composite parts face challenges in withstanding significant radial stresses during large-diameter part production and efficiently removing the part without increasing manufacturing time, especially when the material adheres strongly to the chuck surface.
A mandrel design featuring a forming support with movable angular sectors and actuation mechanisms, including threaded rods, carriages, and connecting rods, allows for stable deployment and retraction under radial stress, with conical bearings and suction/blowing devices for easy part removal.
The mandrel provides stable formation of composite parts under high radial forces and facilitates efficient removal by overcoming adhesion, reducing manufacturing time and ensuring accurate, reproducible profiles.
Smart Images
Figure FR2025050802_19032026_PF_FP_ABST
Abstract
Description
Description Title of the invention: Mandrel for manufacturing a part of revolution from composite material Technical Field
[0001] The present invention relates to a mandrel for manufacturing a part of revolution made of composite material. Previous technique
[0002] The production of a part of revolution in composite material typically includes the use of a mandrel whose outer surface constitutes a support for forming the part, for example by winding or by automatic placement of fibers.
[0003] Once the part is made, it is removed from the chuck. However, the manufactured part may have one or more restrictions that complicate its removal from the chuck.
[0004] Some mandrels are designed to be disassembled to facilitate the removal of parts with necked edges, such as the one described in US29703434. The winding mandrel described in this document comprises four angular sectors arranged around a central axis, which serve as the forming support. To remove the mandrel after winding, its central axis is removed to allow for the manual disassembly and removal of the four sectors. Disassembling and reassembling the mandrel to produce a different part significantly increases manufacturing time.
[0005] To overcome this drawback, chucks with an internal retraction / extension mechanism have been developed, such as the one described in document EP0206268. The chuck described in this document comprises two pairs of angular sectors connected to a central body. The translation of this central body along the chuck's longitudinal axis controls the retraction or extension of the sectors. The radial movement of the angular sectors is achieved by means of a system of grooves in the sectors and slides on the central body that move within these grooves. However, while this mandrel allows the production of small-diameter composite parts, it is not suitable for winding fibers under high tension for large-diameter parts. Indeed, the internal mechanism of this mandrel cannot withstand intense radial stresses, causing the mandrel's forming support to retract during part manufacturing.
[0006] One solution proposed in US4436574 is to combine the internal retraction / extension mechanism with a system configured to mechanically lock the angular sectors when the chuck is extended. This system improves the chuck's resistance to radial stresses. However, this chuck is not suitable for manufacturing composite parts where the material can adhere strongly to the chuck surface. This is because the internal mechanism of this chuck is not designed to provide sufficient force during retraction to overcome the adhesive strength of such a material.
[0007] It is therefore desirable to have a mandrel for manufacturing a part of revolution in composite material which is capable of withstanding significant radial stresses while facilitating the removal of the part after manufacturing. Description of the invention
[0008] To this end, the present invention proposes, according to one embodiment, a mandrel for manufacturing a part of revolution made of composite material, comprising: - a forming support movable along a radial direction and exhibiting rotational symmetry about a longitudinal axis, the forming support comprising a first pair of angular sectors opposed to each other with respect to the longitudinal axis of the mandrel and a second pair of angular sectors opposed to each other with respect to the longitudinal axis, and - a first actuation mechanism configured to move the angular sectors of the first pair of angular sectors between a deployment position and a retraction position, - a second actuation mechanism configured to move the angular sectors of the second pair of angular sectors between a position of deployment and a retraction position, characterized in that the first and second actuation mechanisms each comprise: - a threaded rod extending along the longitudinal axis, - at least one carriage cooperating with the threaded rod and configured to slide along the longitudinal axis when the threaded rod is rotated, and - at least one radial translation means in connection with each angular sector of one of the first or second pairs of angular sectors, said radial translation means being connected with the carriage and configured to radially translate the angular sector during the rotation of the threaded rod.
[0009] The invention thus proposes a mandrel for the manufacture of a part of revolution in composite material having a reversible operation between a deployed configuration allowing the formation of the part and a retracted configuration allowing the removal of the mandrel from the manufactured part.
[0010] The actuation mechanisms for each angular sector of the chuck of the invention improve the stability of the chuck's deployed configuration, even when subjected to significant radial force. Furthermore, during chuck retraction, this mechanism provides sufficient force to overcome the potential adhesion force of the material deposited on the chuck's outer casing.
[0011] According to a particular feature, the chuck comprises first and second carriages and wherein the radial translation means comprises first and second connecting rods, each having a first end and a second end, the first end of the first connecting rod and the first end of the second connecting rod are connected to each other by a pivoting link, the second end of the first connecting rod being connected to the first carriage and the second end of the second connecting rod being connected to the second carriage.
[0012] The use of connecting rods allows for a reversible mechanism capable of applying greater force to the angular sectors, whether during the deployment or retraction of the chuck. An additional advantage of The use of connecting rods is that they provide good accuracy in the radial position of angular sectors.
[0013] According to another distinctive feature, the chuck also includes first and second guide plates, the first guide plate being connected to the first carriage and the second end of the first connecting rod, and the second guide plate being connected to the second carriage and the second end of the second connecting rod. The guide plates ensure a uniform transmission of mechanical forces to the connecting rods.
[0014] According to another particular feature, each angular sector of the first and second pairs of angular sectors is fixed to a support plate connected to a radial translation means. The support plate facilitates the transmission of forces from the actuation mechanism to the angular sectors.
[0015] According to another particular feature, at least one axial end of each angular sector of the first and second pairs of angular sectors is in sliding contact with a fixed part of the mandrel via conical bearing surfaces, so as to lock the angular sectors of the first and second pairs of angular sectors in a predetermined position in the deployed configuration. This feature allows for mechanical locking of the mandrel deployment and contributes to obtaining a reproducible linear profile.
[0016] Another distinctive feature is that the mandrel's forming support has multiple perforations connected to a suction or blowing device. This feature allows for the evacuation of gases from the part's polymerization or facilitates the part's removal from the mandrel surface during its retraction. Brief description of the drawings
[0017] [Fig. 1] Figure 1 is a schematic perspective view of a chuck in its deployed configuration according to one embodiment of the invention,
[0018] [Fig. 2] Figure 2 is a schematic view of the top of the chuck shown in Figure 1,
[0019] [Fig. 3] Figure 3 is a schematic side view of the chuck shown in Figure 1,
[0020] [Fig. 4] Figure 4 is a schematic perspective view of the internal structure of the chuck in Figure 1 in its deployed configuration.
[0021] [Fig. 5] Figure 5 is another schematic perspective view of the internal structure of the chuck in Figure 1 in its deployed configuration.
[0022] [Fig. 6] Figure 6 is a schematic cross-sectional view of the chuck of Figure 1 in its deployed configuration,
[0023] [Fig. 7] Figure 7 is a schematic view of a cross-section of the chuck of Figure 1 in transition between a deployed and a retracted configuration,
[0024] [Fig. 8] Figure 8 is a schematic cross-sectional view of the chuck of Figure 1 in its retracted configuration,
[0025] [Fig. 9] Figure 9 is an enlargement of box VII in Figure 5,
[0026] [Fig. 10] Figure 10 is an enlargement of box VIII of figure 5. Description of the implementation methods
[0027] The invention is now described by means of figures, which are provided for descriptive purposes to illustrate certain embodiments of the invention and which should not be interpreted as limiting the latter.
[0028] Figures 1 to 10 represent a chuck 10 according to an embodiment of the invention. Figures 1 to 3 are schematic views of the chuck 10, Figure 1 being a perspective view of the chuck 10, Figure 2 being a top view of the chuck 10, and Figure 3 being a side view of the chuck 10. The chuck 10 comprises a first pair of angular sectors 11 and 12 opposed to each other by relative to each other with respect to a longitudinal axis Aw of the chuck and a second pair of angular sectors 21 and 22 opposed to each other with respect to the longitudinal axis Aïo of the chuck (Figure 6). The angular sectors 11 and 12 of the first pair of angular sectors are movable, along a first radial direction DRI, between a deployment position (Figure 6) and a retraction position (Figures 7 and 8). Similarly, the angular sectors 21 and 22 of the second pair of angular sectors are movable, along a second radial direction D2, between a deployment position (Figures 6 and 7) and a retraction position (Figure 8). In figures 1 to 3, all angular sectors 11, 12, 21 and 22 are in their deployment position corresponding to a deployed configuration of the mandrel 10. In this deployed configuration, the angular sectors 11, 12, 21 and 22 together form a forming support Sf.
[0029] The chuck 10 includes a first actuating mechanism configured to move the angular sectors 11 and 12 of the first pair of angular sectors between the deployment position and the retraction position and a second actuating mechanism configured to move the angular sectors 21 and 22 of the second pair of angular sectors between the deployment position and the retraction position.
[0030] According to the invention, each angular sector actuation mechanism of a pair of angular sectors comprises a threaded rod extending along the longitudinal axis, at least one carriage cooperating with the threaded rod and configured to slide in a longitudinal direction parallel to the longitudinal axis Aïo when the threaded rod is rotated, and at least one radial translation means in connection with each angular sector of the pairs of angular sectors, said radial translation means being connected with a carriage and configured to translate radially the angular sector when the threaded rod is rotated.
[0031] Figures 4 and 5 illustrate the structure of the first actuation mechanism housed in an internal part of the chuck 10. In Figures 4 and 5, the chuck 10 is in the deployed configuration, i.e. with all the angular sectors in their deployed position, only the angular sectors 11 and 12 of the first pair of angular sectors being shown in Figures 4 and 5.
[0032] The first actuation mechanism includes a first threaded rod 100 (figure 5) extending along the longitudinal axis Aïo, as well as first 111 and second 112 carriages each cooperating with the first threaded rod 100. For this purpose, the first 111 and second 112 carriages each have a threaded insert (not shown in figures 4 and 5) through which the threaded rod passes so that the rotation of the threaded rod causes the movement of the carriages 111 and 112 along the longitudinal axis Aïo. The threads of the inserts of the two carriages are reversed so that the rotation of the first threaded rod 100 along a first direction of rotation SI causes the two carriages 111 and 112 to move apart and so that the rotation of the first threaded rod 100 along a second direction of rotation S2 of the threaded rod 100 causes the two carriages 111 and 112 to move closer together.Furthermore, each angular sector 11 and 12 of the first pair of angular sectors is linked to radial translation means. Each radial translation means is connected to the first 111 and the second 112 carriages. When the two carriages move apart, each radial translation means moves one angular sector closer to the longitudinal axis Aio of the chuck 10, while when the two carriages 111 and 112 move closer to each other, the radial translation means moves one sector away from the longitudinal axis Aio of the chuck.
[0033] More specifically, in the example described here, each radial translation means comprises first and second connecting rods 81 and 82, each having first ends 811 and 821 and second ends 812 and 822. The first end 811 of the first connecting rod 81 and the first end 821 of the second connecting rod 82 are connected to each other by a pivot joint itself connected to an angular sector such as the angular sector 12 shown in Figure 4. The second end 812 of the first connecting rod 81 is connected to the first carriage 111 while the second end 822 of the second connecting rod 82 is connected to the second carriage 112.Thus, when the first and second carriages 111 and 112 approach each other, the second end 812 of the first connecting rod 81 approaches the second end 822 of the second connecting rod 82, which causes the first ends 811 and 821 of both connecting rods 81 and 82 to move away from the longitudinal axis Aïo of the chuck and, consequently, the radial displacement of the angular sector of the longitudinal axis Aïo towards its deployment position. When. the first and second carriages 111 and 112 move away from each other, the second end 812 of the first connecting rod 81 moves away from the second end 822 of the second connecting rod 82, which causes the first ends 811 and 821 of the first and second connecting rods 81 and 82 to move closer to the longitudinal axis Aw of the chuck and, consequently, the radial displacement of the angular sector towards its retraction position.
[0034] In the example described here, the radial translation means are connected to the first and second carriages 111 and 112 via first and second guide plates 71 and 72. For each radial translation means, the first guide plate 71 is fixed to the first carriage 111 and to the second end 812 of the first connecting rod 81, while the second guide plate 72 is fixed to the second carriage 112 and to the second end 822 of the second connecting rod 82. Each guide plate follows the movement of the carriage to which it is attached. The movement of the first and second carriages 111 and 112 in opposite directions causes the first and second guide plates 71 and 72, which are capable of sliding in shear relative to each other, to translate along the longitudinal axis A10 of the chuck.Each of the guide plates being joined to the second end 812, 822 of the two connecting rods 81 and 82, their relative translational movement in opposite directions allows the angular sector to be brought closer to or further from the longitudinal axis Aio of the chuck.
[0035] The actuation means that set in motion the angular sectors 21 and 22 of the second pair of angular sectors comprise the same elements and have the same kinematics as the actuation means associated with the angular sectors 11 and 12 of the first pair of angular sectors. For the sake of simplicity, they are not described again here. The movement of the angular sectors 21 and 22 of the second pair of angular sectors is initiated by the rotation of a second threaded rod 200 (Figure 5).
[0036] Figures 6 to 8 represent a cross-section of the chuck in transition, figure 6 in deployed configuration, figure 8 in retracted configuration and figure 7 in transition between the deployed and retracted configurations.
[0037] According to the invention, the mandrel is configured to manufacture composite material parts exhibiting rotational symmetry about a longitudinal axis Aw, and in particular allows the manufacture of parts having necks St, each characterized by cross-sections of different diameters. For example, the mandrel illustrated in Figures 1 to 3 allows the manufacture of a part of revolution having a single neck St, that is, a continuous longitudinal zone characterized by a narrowing of the cross-sectional diameter.
[0038] According to the invention, the mandrel has an extended and a retracted configuration. In the extended configuration, the outer surface of the mandrel constitutes a forming support Sf around which the fibers are deposited to fabricate a part of revolution made of composite material. The forming support Sf corresponds to the inner surface of the part to be manufactured.
[0039] In one embodiment, the mandrel forming support is divided into first pairs 11, 12 and second pairs 21, 22 of angular sectors. The sectors of each of the first and second pairs of sectors are identical and opposite each other with respect to the longitudinal axis of the mandrel. The sectors 21, 22 of the second pair of angular sectors have a perimeter greater than that of the sectors 11, 12 of the first pair of angular sectors. In the extended configuration, for each pair of angular sectors, the two sectors of each pair of angular sectors are separated by a distance D1, determined by the minimum cross-sectional diameter of the composite workpiece to be manufactured. In the retracted configuration, the two sectors 21, 22 of the second pair of angular sectors are separated by a distance D2, which is less than the distance D1.Furthermore, in the retracted configuration, sectors 11 and 12 of the first pair of angular sectors are separated by a distance D3, which is less than distance D2. This distance is determined to provide sufficient space to allow the retraction of angular sectors 21 and 22 of the second pair of angular sectors. Since the maximum transverse dimension of the chuck in its retracted configuration is less than the minimum transverse dimension of the chuck in its extended configuration, the retracted configuration allows the chuck to be extracted from the workpiece.
[0040] According to one embodiment, the adjacent sectors of the first 11, 12 and second 11, 12 pairs of sectors are in sliding contact in the deployed configuration of the chuck. The walls 31, 32 of the adjacent sectors that form the interface of said sectors are beveled (Figures 7 and 8). Furthermore, the beveled geometry of the walls 31, 32 of the angular sectors is such that, in the deployed configuration of the chuck, the radial approach of the sectors 21, 22 of the second pair of angular sectors is mechanically prevented by the sectors 11, 12 of the first pair of angular sectors.
[0041] In one embodiment, the axial ends 4, 5 of each sector of the first 11, 12 and second 21, 22 pairs of angular sectors are in sliding contact with a fixed part of the chuck via conical bearing surfaces so as to lock the angular sectors of the first 11, 12 and second 21, 22 pairs of angular sectors in a predetermined position in the deployed configuration. The fixed part of the chuck mechanically prevents the distance separating the two sectors of a pair of angular sectors from increasing beyond a maximum distance DI determined by the dimensions of the workpiece to be manufactured.
[0042] According to the invention, actuation means for the forming support Sf guide the radial translation of the angular sectors 11, 12, 21, 22 so as to change the configuration of the mandrel. The radial displacement of the two angular sectors of the same pair of angular sectors is identical. During the transition from the retracted configuration to the extended configuration, the actuation means induce an increase in the distance separating the two sectors of the pairs of angular sectors. During the transition from the extended configuration to the retracted configuration, the actuation means induce a decrease in the distance separating the two sectors of the pairs of angular sectors.
[0043] According to one embodiment, the transition between the deployed and retracted configurations of a chuck having a first pair of angular sectors (11, 12) and a second pair (21, 22) is carried out in two successive steps, each associated with the movement of a pair of angular sectors. These two steps are identical for both types of transitions, deployment or retraction of the chuck, and their The order is reversed. In the first step of the transition from the deployed to the retracted configuration of the chuck, the actuation means perform the simultaneous radial translation of sectors 11, 12 of the first pair of angular sectors until they are separated by a distance D3. At the end of the first step, the new position of sectors 11, 12 of the first pair of angular sectors allows the sectors of the second pair of angular sectors 21, 22 to be freed from the mechanical constraint imposed by the position of sectors 11, 12 of the first pair of angular sectors in the deployed configuration of the chuck. In the second step, the actuation means of the forming support Sf then perform the simultaneous radial translation of sectors 21, 22 of the second pair of angular sectors until they are separated by a distance D2.At the end of the second step, sectors 21, 22 of the second pair of angular sectors partially cover the surface of sectors 11, 12 of the first pair of angular sectors, and the transverse dimension of the mandrel is small enough to allow its extraction from the manufactured part.
[0044] According to one embodiment, each angular sector of the chuck is fixed on a support plate 6 in connection with a radial translation means.
[0045] According to one embodiment, the forming support Sf of the mandrel comprises a plurality of perforations 3 connected to a suction or insufflation device.
[0046] The transition process from the extended to the retracted configuration of the chuck is now described. The retraction movement of the chuck is initiated by the rotation of the threaded rods 100, 200. Each threaded rod controls the movement of a pair of sectors. For each threaded rod 100, 200, its movement in the first direction of rotation SI induces the separation of the two carriages 111, 112 through which it passes. The separation of the first 111 and second 112 carriages induces the first shearing movement of the first 71 and second 72 guide plates. This movement of the guide plates induces the separation of the second end 812, 822 of the first 81 and second 82 connecting rods of the two pairs of connecting rods of each of the sectors of the pair of angular sectors, and by extension brings the point of junction of the first 811, 821 end of the connecting rods closer to the central axis of the chuck. support plates 6 attached to the first 811, 821 end of the connecting rods are then brought closer to the central axis of the chuck, and consequently the angular sectors fixed on each of the support plates 6.
Claims
Demands
1. Mandrel (10) for manufacturing a part of revolution made of composite material, comprising: - a forming support (Sf) movable along a radial direction (DRI, DZ) and exhibiting rotational symmetry about a longitudinal axis (Aïo), the forming support (Sf) comprising a first pair of angular sectors (11, 12) opposed to each other with respect to the longitudinal axis (Aïo) of the mandrel and a second pair of angular sectors (21, 22) opposed to each other with respect to the longitudinal axis (Aïo), and - a first actuation mechanism configured to move the angular sectors (11, 12) of the first pair of angular sectors between a deployment position and a retraction position, - a second actuation mechanism configured to move the angular sectors (21, 22) of the second pair of angular sectors between a deployment position and a retraction position, characterized in that the first and second actuation mechanisms each comprise: - a threaded rod (100, 200) extending along the longitudinal axis (Aïo), - at least one carriage (111, 112) cooperating with the threaded rod (100, 200) and configured to slide along the longitudinal axis (Aïo), when the threaded rod (100, 200) is rotated, and - at least one radial translation means in connection with each angular sector of one of the first (11, 12) or second (21, 22) pairs of angular sectors, said radial translation means being connected with the carriage (111, 112) and configured to radially translate the angular sector during the rotation of the threaded rod (100, 200).
2. Chuck according to claim 1, comprising first (111) and second (112) carriages and wherein the radial translation means comprises first (81) and second (82) connecting rods, each having a first (811, 821) end and a second (812, 822) end, the first (811) end of the first (81) connecting rod and the first (821) end of the second (82) connecting rod are connected to each other by a pivoting link, the second (812) end of the first (81) connecting rod being connected to the first (111) carriage and the second (822) end of the second (82) connecting rod being connected to the second (112) carriage.
3. Chuck according to claim 2, further comprising first (71) and second (72) guide plates, the first (71) guide plate being connected to the first (111) carriage and to the second (812) end of the first (81) connecting rod, and the second (82) guide plate being connected to the second (112) carriage and to the second (822) end of the second (82) connecting rod.
4. Chuck according to any one of claims 1 to 3, wherein each angular sector of the first (11, 12) and second (21, 22) pairs of angular sectors is fixed on a support plate (6) in connection with a radial translation means.
5. Chuck according to any one of claims 1 to 4, wherein at least one axial end (4, 5) of each angular sector of the first (11, 12) and second (21, 22) pairs of angular sectors is in sliding contact with a fixed part of the chuck via conical bearings so as to lock the angular sectors of the first (11, 12) and second (21, 22) pairs of angular sectors in the deployment position.
6. Mandrel according to any one of claims 1 to 5, wherein the forming support (Sf) comprises a plurality of perforations (3) connected to a suction or insufflation device.
7. Mandrel according to any one of claims 1 to 6, wherein the forming support (Sf) comprises at least one necking (St) in deployed configuration.
Citation Information
Patent Citations
Winding mandrel for producing tubes from rovings of resinous filaments
EP0206268A2
Radial mandrel
US4436574A
US29703434B1