Thermal junction system between two movable structural elements in a space environment

Abstract

The invention relates to a thermal junction system (1) comprising first and second structural elements (2, 3) and forming the thermal junction between a first interface (2a) of the first structural element (2) and a second interface (3a) of the second structural element (3), the first and second structural elements being intended to be integrated into a spacecraft, characterised in that the first and second structural elements (2, 3) are in the form of planar extended panels with the first and second interfaces (2a, 3a) having the form of planar surfaces, the thermal junction system (1) comprising: - a mechanical guidance system (6) which is configured to bring the first and second movable structural elements (2, 3) closer together from at least one open position, in which the first and second interfaces (2a, 3a) are spaced apart from one another, and a closed position, in which the first and second interfaces (2a, 3a) are clamped against one another so as to be thermally connected; - a thermal seal (5) which extends over one and / or the other of the first and second interfaces (2a, 3a), the thermal seal (5) comprising a dry material or a thermal paste and having a thermal conductance of greater than or equal to 1000 W / m² / K; - a triggering system (7) which is configured to trigger at least one movement of the first and second structural elements (2, 3) from the open position to the closed position; - a compression system (8) which is configured at least to press the first and second interfaces (2a, 3a) against one other in the closed position.

Description

Description Title: Thermal junction system between two mobile structural elements in a space environment technical field

[0001] This disclosure falls within the domain of space equipment, more specifically the heat transfer of such space equipment, particularly satellites. It concerns in particular a thermal junction system between two structural elements that are movable relative to each other. Previous technique

[0002] In the space sector, thermal bonding between two structures via a mechanism or joint is achieved using thermal braids, fluidic systems, or thermal grease systems. The purpose of such systems is, for example, to dissipate heat from a satellite using deployable radiators.

[0003] Thermal braids are flexible structures, using highly conductive materials such as aluminum, copper, graphite, or graphene, that allow for the thermally conductive connection of two structures. They are simple but have limited performance: the more flexible the system, the longer or thinner it must be, which is counterproductive for achieving good thermal conduction, which requires short, thick braids. Conversely, short, thick braids that offer good thermal conductivity are less flexible, which is also problematic. Furthermore, these braids must be connected to the two structures via contacts, either dry or enhanced with thermal seals, but these connections generate thermal coupling losses due to the number of intermediate parts and contact points.

[0004] Fluidic systems comprise a fluid network, including a pump or heat pipes, arranged between structures to be thermally connected. At joints, flexible tubes are generally used to ensure the circulation of the heat transfer fluid while providing the necessary flexibility for movement. However, this results in a complex structure and difficulties in making it compact, as flexible tubes typically require bend radii greater than 50 mm. Furthermore, pump-based systems are generally expensive.

[0005] Finally, in thermal grease systems, the two structures are in near-permanent contact via a conductive and lubricating grease. Such systems are bulky and limit the possible relative movements due to this near-contact, requiring the addition of dedicated interfaces. Besides the added weight and cost, the addition of these dedicated interfaces also negatively impacts thermal performance and compactness.

[0006] EP1033302 is known to be a heat transfer connection device for spacecraft.

[0007] There is therefore a need for a new thermal junction system at the point of connection between two moving elements. Summary

[0008] This disclosure improves the situation.

[0009] A thermal junction system is proposed comprising first and second structural elements and achieving thermal junction between a first interface of the first structural element and a second interface of the second structural element, the first and second structural elements being intended to be integrated into a spacecraft, characterized in that the first and second structural elements are in the form of extended flat panels with the first and second interfaces being in the form of flat surfaces, the thermal junction system comprising: a mechanical guidance system configured to bring the first and second movable structural elements closer together from at least an open position where the first and second interfaces are separated from each other and a closed position where the first and second interfaces are pressed against each other to be thermally connected,a thermal seal extending over one and / or the other of the first and second interfaces, the thermal seal comprising a dry material or a thermal paste and having a thermal conductance greater than or equal to 1000 W / m, 2 / K, a triggering system configured to trigger at least one movement of the first and second structural elements from the open position to the closed position, a compression system configured at least to compress the first and second interfaces against each other in the closed position.

[0010] In some examples, the thermal seal is fixed to the first interface of the first structural element.

[0011] The features described in the following paragraphs may optionally be implemented independently of each other or in combination with each other.

[0012] The guidance system can be configured, in particular, to guide the second structural element in movement relative to the first structural element.

[0013] The open position before triggering could, for example, correspond to a compact configuration at launch. The closed position could, for example, correspond to a The configuration is deployed after launch and after deployment. In this case, the open position is a preparatory position and the closed position is an operational position.

[0014] The triggering system may, for example, include at least one holding and releasing mechanism. The triggering system may be active or passive, preferably passive.

[0015] The mechanical guidance system and the compression system can, for example, be of the passive type.

[0016] The guidance system may, for example, include an elastic element tending to bring the first and second structural elements closer to the closed position.

[0017] The guidance system may include, for example, a first actuator controlled by a first control signal generated according to a state of the triggering system.

[0018] The compression system may include, for example, a second actuator controlled by a second control signal and / or an elastic element designed to exert the compression force. The second control signal is, for example, generated by the triggering system.

[0019] The first control signal and the second control signal, respectively controlling the first and second actuator, can for example be generated simultaneously, consecutively or separately in time.

[0020] The first actuator of the guidance system can, for example, be distinct from the second actuator of the compression system. Alternatively, the first actuator can, for example, be the same as the second actuator.

[0021] The first actuator in the guidance system can be either passive or active. Similarly, the second actuator in the compression system can be either passive or active. "Passive" refers to an actuator actuated by a spring, a natural magnet, or any component activated by a change in environment (such as a temperature variation) or by a change in the state of another, separate actuator (e.g., the release of a holding mechanism such as an HRM). A passive actuator is not directly controlled. "Active" refers to an actuator actuated by an electric motor, a coil-based magnet, a shape-memory material requiring external heating, or any component activated by an external control signal. An active actuator is directly controlled. For example, an active actuator receives electrical or hydraulic power for its operation.

[0022] The compression system can, for example, use a system of links to increase the lever arms, if necessary, and increase the pressure-setting force.

[0023] The first structural element could, for example, be a structural panel of the spacecraft, and the second structural element could be a spacecraft radiator. In this case, the system allows heat to be dissipated from the spacecraft's structural panel, particularly the satellite, to space via the spacecraft's radiator, which is a thermally conductive element, when the first and second interfaces are thermally connected, in the closed position.

[0024] The thermal seal consists of a dry material or thermal paste. When the thermal seal consists of a dry material, it may be necessary to hold it in place in some way, such as with an adhesive film or mechanically. The thermal seal has a thermal conductance greater than or equal to 1000 W / m 2 / K. This refers to the conductive coupling reduced to the surface "in the plane" of the thermal seal, also taking into account the thickness. When the thermal seal contains thermal paste, it may be necessary to heat it to facilitate its compression.

[0025] For example, a local modification of the surface finish can be implemented, such as polishing, laser treatment, or chemical treatment, to achieve a specific surface finish that promotes thermal contact. This specific surface finish can be applied to both interfaces intended for thermal contact via one or more thermal seals. Alternatively, a coating could be applied to one or both interfaces. The compression system can be configured to apply a crushing pressure ranging from 1 N to 1000 N, or even up to 10,000 N. This pressure depends on the thermal seal, specifically its flexibility, performance, initial thickness, and the surface area to be compressed.

[0026] The first and / or second structural elements may, for example, include first and / or second heat transfer systems flush with their first and / or second interfaces. Such a heat transfer system includes, for example, a heat pipe.

[0027] The first and second structural elements can, for example, be of the sandwich type, formed from machined or 3D-printed parts, and / or be composed of several conductive elements. They can be made, in whole or in part, of all types of metallic, ceramic, plastic, carbon, honeycomb panel, or other materials, for example, pyrolytic graphite.

[0028] The first and second structural elements can, for example, be mobile in rotation relative to each other.

[0029] The guidance system may, for example, include a pivot with an axis of rotation, the movement of the second structural element from the open position to the closed position including a rotation around the axis of rotation of the pivot, for example a rotation of an angle of 180°.

[0030] The guidance system may, for example, include a slide that induces a translation of the second structural element relative to the first structural element.

[0031] The guidance system may include, for example, a delay mechanism configured to hold the compression system in a raised position, then to release the compression system in the closed position. The delay mechanism may, for example, take the form of a cam attached to the second structural element. The cam comprises a circular guide surface followed by a housing that receives a roller in the closed position. The roller belongs to the compression system and drives a support arm configured to bear against the second structural element in the closed position. The support arm is rotatable relative to the first structural element.

[0032] The support arm can, for example, be configured to pass through a passage made in the second structural element when the support arm is in its raised position.

[0033] The compression system may include, for example: a movable drive arm rotating relative to the first structural element, the drive arm being connected to the roller, and a force multiplier arm articulated on one side relative to the support arm and on the other side relative to the drive arm.

[0034] The thermal junction system according to the present invention may, for example, be without a hydraulic actuator.

[0035] A system as described in this disclosure advantageously limits the number of structural elements in the thermal coupling path. In the closed position, the heat flux passes from the first structural element to the second structural element solely through the thermal seal, thereby maximizing heat transfer performance.

[0036] Another advantage of this disclosure is that the use of the thermal seal makes it possible to compensate for microscopic and macroscopic defects, thus ensuring a desired contact surface between the two structural elements and making it possible to achieve, with the help of the compression system, a sufficient level of pressure for the thermal seal to be effective, especially with a reduced thickness.

[0037] Even more advantageously, the system described in this disclosure limits the constraints on the relative movements that allow thermal contact between the two structural elements. Thus, all sorts of movements are possible to transition from the open to the closed position.

[0038] Another advantage of this disclosure is that the first structural element can be thermally coupled or not to the second structural element, particularly before deployment, i.e., before the transition from the open to the closed position. The advantage is, for example, to limit heat exchange before deployment, i.e., in the open position, which can be useful, for instance, in the case of a deployable radiator whose function is to The goal is to limit heat rejection during a satellite's orbital insertion and storage configuration, where thermal losses are minimized to maximize the use of available power, for example, for electric propulsion. The satellite can then increase heat rejection, via the deployable radiator, once in orbit in its deployed configuration—that is, in the closed position—where heat loss to space is maximized and care is taken to prevent overheating of the equipment. Brief description of the drawings

[0039] Other features, details, and advantages will become apparent upon reading the detailed description below and analyzing the attached drawings, on which:

[0040] [Fig. 1] shows, in schematic cross-sectional view, a thermal junction system according to an example, in an open position.

[0041] [Fig. 2] shows, in schematic cross-sectional view, a thermal junction system according to the example in Figure 1, in a closed position.

[0042] [Fig. 3] shows, in schematic cross-sectional view, a thermal junction system according to an example, in an open position.

[0043] [Fig. 4] shows, in schematic cross-sectional view, the thermal junction system according to the example in Figure 3, in an intermediate position.

[0044] [Fig. 5] shows, in schematic cross-sectional view, the thermal junction system according to the example in Figure 3, in an intermediate position.

[0045] [Fig. 6] shows, in schematic cross-sectional view, the thermal junction system according to the example in Figure 3, in an intermediate position.

[0046] [Fig. 7] shows, in schematic cross-sectional view, the thermal junction system according to the example in Figure 3, in an intermediate position.

[0047] [Fig. 8] shows, in schematic cross-sectional view, the thermal junction system according to the example in Figure 3, in a closed position.

[0048] [Fig. 9] is a perspective view of an example of an insert intended to be integrated into a second moving element of an example of a thermal junction system.

[0049] [Fig. 10] schematically shows, in cross-section, an example of a thermal junction system.

[0050] [Fig. 11] schematically shows, in cross-section, an example of a thermal junction system.

[0051] [Fig. 12] schematically shows, in cross-section, an example of a thermal junction system.

[0052] [Fig. 13] schematically shows, in cross-section, an example of a thermal junction system.

[0053] [Fig. 14] schematically shows, in cross-section, an example of a thermal junction system.

[0054] [Fig. 15] schematically shows, in cross-section, an example of a thermal junction system.

[0055] [Fig. 16] schematically shows, in cross-section, an example of a thermal junction system.

[0056] [Fig. 17] schematically shows, in cross-section, an example of a thermal junction system. Description of the implementation methods

[0057] In the various figures, the same reference numerals designate identical or similar elements. For the sake of brevity, only the elements that are useful for understanding the described embodiment are shown in the figures and are described in detail below.

[0058] Reference is now made to Figures 1 and 2. They represent a thermal junction system 1 between a first interface 2a of a first structural element 2 and a second interface 3a of a second structural element 3 of a spacecraft.

[0059] In one example, the first structural element 2 is a structural panel of the spacecraft and the second structural element 3 is a radiator of the spacecraft.

[0060] The thermal junction system 1 includes a mechanical guide system 6 configured to connect the first and second structural elements 2, 3 movable relative to each other, between at least a first position, called the open position, as illustrated in Figure 1, where the first and second interfaces 2a, 3a are separated from each other and a second position, called the closed position, as illustrated in Figure 2, where the first and second interfaces 2a, 3a are thermally connected.

[0061] As illustrated in Figures 1 and 2, the first and second structural elements 2 and 3 are, for example, rotationally mobile relative to each other. In particular, in this example, the guide system 6 includes a pivot 10 with an axis of rotation. The movement of the second structural element 3 from the open position to the closed position involves a rotation around the axis of rotation of the pivot 10; in this example, a rotation through an angle A of 180°, as shown in the dashed line in Figure 2. It should be noted that the thermal junction system 1, for example, allows for limiting the constraints on the relative movements, such that different movements are possible, enabling, in particular, the second structural element 2 to move from the open to the closed position.

[0062] As shown in Figure 1, the thermal junction system 1 includes, for example, a thermal seal 5 fixed to one or the other of the first and second interfaces 2a, 3a, in this example to the first interface 2a.

[0063] We could also consider, for example, two thermal seals, one thermal seal being placed on each interface.

[0064] For example, one could also consider a specific surface condition obtained by surface treatment by polishing, laser or chemical or a coating on one or both interfaces, complemented with a thermal seal on one or both interfaces.

[0065] As shown in Figure 2, the thermal seal 5 is positioned so that it is interposed between the first and second interfaces 2a and 3a in the closed position. Thus, the thermal coupling path in the closed position runs, for example, from the first structural element 2 at the first interface 2a to the second structural element 3 at the second interface 3a, passing only through the thermal seal 5. The number of structural elements in the thermal coupling path is therefore limited, maximizing heat transfer performance.

[0066] The thermal junction system 1, for example, includes a triggering system 7, symbolized here by a spring, configured to trigger at least one movement of the first and second structural elements 2, 3 from the open position to the closed position. The triggering system 7 includes, for example, at least one hold and release mechanism, also called an HRM or HDRM (Hold Down and Release Mechanism). The HDRM mechanism can, for example, directly release the radiator, which then begins to move. Alternatively, the release and movement of the radiator can, for example, be conditioned on the state of a specific HDRM of the spacecraft.

[0067] The thermal junction system 1 includes, for example, a compression system 8 configured at least to compress the first and second interfaces 2a, 3a against each other in the closed position, as illustrated in Figure 2.

[0068] Thermal gasket 5 may contain, for example, a dry material or thermal paste. When thermal gasket 5 contains a dry material, such as the type known commercially as Cho-therm® or Sigraflex®, it may be necessary to hold it in place in some way, such as with an adhesive film or mechanically. When thermal gasket 5 contains, for example, thermal paste, it may be of the type known commercially as SF10, marketed by Laird. The thermal paste may, for example, be heated to facilitate its compression.

[0069] Thermal seal 5 has a thermal conductance greater than or equal to 1000 W / m 2 / K. This refers to the conductive coupling brought to the surface in what can be called the plane of the thermal joint 5, also taking into account the thickness.

[0070] The use of the thermal seal 5 makes it possible to compensate for microscopic and macroscopic defects, thus ensuring a desired contact surface between the first and second interfaces 2a and 3a, therefore between the first and second structural elements 2 and 3, and making it possible to reach, with the help of the compression system 8, a sufficient level of pressure for the thermal seal 5 to be effective, especially with a reduced thickness.

[0071] The first structural element 2 can be, optionally, thermally coupled or not to the second structural element 3 before the transition from the open to the closed position. However, the advantage of not having thermal coupling outside the closed position can be to Limiting heat exchange in the open position or even in an intermediate position (i.e., outside the closed position) can be useful, for example, when the second structural element 3 is a deployable radiator whose function is to promote heat rejection from the spacecraft, such as a satellite, one structural panel of which forms the first structural element 2, during the orbital insertion phase and in storage configuration where heat losses are minimized to promote the use of electrical energy for electric propulsion, for example. The satellite can then, for instance, increase heat rejection once in orbit in the deployed configuration, i.e., in the closed position of the thermal junction system, where heat losses are maximized and care is taken to prevent overheating of the equipment.

[0072] As illustrated in Figures 1 and 2, the open position before triggering corresponds, for example, to a compact configuration at launch. The closed position corresponds, for example, to a fully deployed position. Between the open and closed positions are intermediate positions.

[0073] The first structural element 2 and / or the second structural element 3 may, for example, be of the honeycomb sandwich type, formed from machined or 3D-printed parts, and / or be formed from several conductive elements. The first structural element 2 and / or the second structural element 3 may, for example, be composed, in whole or in part, of all types of metallic, ceramic, plastic, carbon, honeycomb panel, or other materials, for example, pyrolytic graphite.

[0074] As illustrated in Figures 1 and 2, the first and second structural elements 2 and 3 each include, for example, a heat transfer system 9 flush with the first and second interfaces 2a and 3a, respectively. This heat transfer system 9 includes, for example, one or more heat pipes. This improves heat transfer.

[0075] Alternatively, the first and second structural elements 2 and 3 can, for example, be conductive due to their intrinsic properties.

[0076] We will now describe in detail the examples illustrated in figures 3 to 8.

[0077] As illustrated in Figures 3 to 8, the guidance system 6, for example, comprises a first actuator, and the compression system 8 comprises a second actuator, the first and second actuators being distinct from one another. The second actuator is, for example, of the geared type, as will be explained later. The gearing maximizes compactness while achieving a predetermined preload, i.e., compression, required in the closed position, all while remaining a passive system and minimizing the impact on the drive unit and on electrical energy reserves.

[0078] As illustrated in figures 3 to 8, the guidance system 6 includes, for example, a spring ensuring direct motorization between the second structural element 3 and the pivot 10.

[0079] As illustrated in Figures 3 to 8, the guide system 6 includes, for example, a delay mechanism configured to hold the compression system 8 in a raised position, i.e. in a position not applying pressure, illustrated in Figures 3 to 6, and then to allow the compression system 8 to position itself in the closed position as illustrated in Figure 8.

[0080] The compression system 8 includes, for example, a roller 17. The delay mechanism includes, for example, a cam 12 attached to the second structural element 3. In this example, the cam 12 is driven in rotation around the pivot 10 simultaneously with the second structural element 3. The cam 12 includes a circular guide surface 13 followed by a housing 14 configured to receive the roller 17 in the closed position.

[0081] The compression system 8 includes, for example, a support arm 18 controlled according to the position of the roller 17 and configured to be able to bear against the second structural element 3 in the closed position, when the roller 17 comes into the housing 14. The support arm 18 is movable in rotation relative to the first structural element 2.

[0082] The compression system 8 includes, for example, a movable drive arm 16 that rotates relative to the first structural element 2 around a rotation axis 22. The drive arm 16 is, for example, connected to the roller 17. The compression system 8 also includes, for example, a force-multiplying arm 15 articulated on one side relative to the support arm 18 at a joint 20 and on the other side relative to the drive arm 16 at another joint 21. This compression system 8 makes it possible to multiply the force by providing a reduction ratio that allows a high preload to be applied at the point of application.

[0083] An open position is visualized, for example, in Figure 3. The triggering system 7, in particular an HRM, which retains, for example, the second structural element 3. The guidance system 6 includes, for example, a first actuator controlled by a first control signal generated according to the state of the triggering system 7. The compression system 8 includes, for example, a second actuator controlled by a second control signal, for example generated according to the state of the triggering system 7. The control signals are, for example, generated by the on-board computer which is connected to the triggering system.

[0084] For example, Human Resource Management (HRM) is triggered at the beginning of the orbital insertion process, primarily because the risk of failure increases with time spent in orbit. This necessitates triggering HRM as early as possible. The deployment system, based on disclosure, can be opened immediately after the equipment deployments triggered by HRM, but it can also be opened several days, weeks, months, or even years after the HRM is triggered. The timing of the trigger can be chosen, for example, in the case of an active actuator.

[0085] The compression system 8 may, for example, include, in addition or as a variant, an elastic element tending to exert the compression force.

[0086] The first control signal and the second control signal, respectively controlling the first and second actuator, can for example be generated simultaneously, consecutively or separately in time.

[0087] The first actuator of the guidance system 6 guides, for example in rotation, the second structural element 3 from the open position shown in Figure 3 to the closed position illustrated in Figure 8. In the meantime, the second structural element 3 passes through intermediate positions, as illustrated, for example, in Figures 4 to 7, which show the rotation of the second structural element 3 relative to the first structural element 2. During this rotation, the cam 12 is driven in rotation around the axis of rotation of the pivot 10, while the drive arm 16 tends to be driven in rotation in the same direction as the cam. The drive arm actually rotates, for example, only when the notch 14 reaches a position facing the roller, as shown by the arrows illustrated in Figures 3 to 8 around the axes of rotation of the pivot 10 and 22. This generates the movement of the roller 17 on the circular guide surface 13.Throughout this rotational movement, the motor arm 16 and the force multiplier arm 15 do not change their orientation, remaining immobile relative to the first structural element 2. Thus, the support arm 18 does not change its orientation relative to the structural element 2.

[0088] When the roller 17 reaches the housing 14, as illustrated in Figure 7, the roller is guided into the housing as shown in Figure 8, carrying with it the drive arm 16 such that the joint 20 moves the force-multiplying arm 15, which in turn rotates the support arm 18, which locks onto the second structural element 3 in the closed position, compressing the first interface 2a against the second interface 3a. Furthermore, the cam is prevented from rotating by the roller in its housing.

[0089] As illustrated in Figure 9, the second structural element 3 includes, for example, a passage 19 for the support arm 18, the passage 19 and the support arm 18 being configured to allow the insertion of part of the support arm 18 into the passage and then the locking and support of the support arm 18 on the second structural element 3 in the closed position.

[0090] The first actuator of the guidance system 6 includes, for example, an elastic element, such as a spring arranged around the pivot 10, in two spiral spring parts located on either side of the cam 12, a spring arm connecting the two spring parts.

[0091] The second actuator of the compression system 8 includes, for example, an elastic element, such as a spring arranged around the axis of rotation 22 and in two spiral spring parts located on either side of the motor arm 16 and connected to each other by a spring arm.

[0092] The compression system 8, for example, comprises a frame with two frame sections arranged symmetrically on either side of the force-multiplying arm 15, and articulated on one side to the pivot 10 and on the other to the joint 22 of the support arm. A bearing, for example, a ball bearing, can be provided in the housing of each frame section and around the axis of the pivot 10. A bearing is also provided, for example, in the housing and around the axis of the joint 22. The frame parts allow adjustment of a distance between the pivot 10 and the joint 22 in order to constrain the movement of the motor arm 16, the force multiplier arm 15 and the support arm 18, in particular when passing into the closed position.

[0093] In the closed position, illustrated in Figure 8, the support arm 18, for example, presses, by means of the compression system 8, against an external surface 35 of the second structural element 3, thus creating a thermal connection between the first and second structural elements 2 and 3 at the first and second interfaces 2a and 3a. The pivoting support arm 18 forms, for example, a pivoting head, one end of which contacts a portion 36 radially inward, relative to the pivot 10, of the external surface 35 around the opening 19. The head extends, for example, at a predetermined angle around its axis, with a width increasing along its angular extent. The head is, for example, shaped to present a variable surface area vis-à-vis the second movable element, depending on its angular position.For example, the head passes through the opening 19 during the rotation of the second structural element 3, then pivots back, driven by the movement of the support arm 18 itself, which is itself driven by the force-multiplying arm 15, to position itself against the external surface 35 of the second structural element 3. This external contact surface forms, for example, one or more projecting portions 36 facing inwards through the opening 19. Two projecting portions 36 may, for example, be opposite each other. Thus, the head of the support arm has a width corresponding to the distance between the contact surfaces of these projecting portions. The head of the support arm can therefore freely pass through the opening and fold down onto the projecting portion(s) 36.

[0094] As illustrated in Figure 9, the second structural element 3 includes, for example, a U-shaped connecting structure 38 surrounding the passage 19 and articulated, at two ends 39, around the axis of the pivot 10. The U-shaped structure includes, for example, recesses. The U-shaped structure delimits the passage and the external bearing surface with the support arm. The U-shaped structure is, for example, attached to a panel of the radiator.

[0095] The delay mechanism includes, for example, a cam 12 formed to delay the engagement of the roller 17 in its housing 14, allowing the roller 17 to press at the end of its travel in the designated housing and then to insert itself at the bottom of the housing in order to apply the compression with a slight delay relative to the deployment of the second structural element 3. Thus, the second structural element 3 is fully deployed before the rotation of the support arm 18 forming a lock, so as to avoid any blockage between the second structural element 3 and the support arm 18.

[0096] In figures 10 to 17, the second structural element 3 is visualized in solid lines in the open position while the second structural element 3 is represented in dotted lines, in an intermediate position and in the closed position.

[0097] As shown in figures 10 to 17, the movement of the second structural element 3 to move from the open position to the closed position is, for example, a rotation of 180° around an axis, but other types of movements could be considered.

[0098] In the examples in figures 10 to 12, the first and second actuators are, for example, confused.

[0099] In the examples in Figures 13 to 17, the first and second actuators are separate. When the first and second actuators are separate, the deployment from the open position to the closed position requires less power.

[0100] As shown in Figure 10, the first and second actuators form, for example, a single actuator comprising a torsion bar made of shape memory material (AMF), with or without a reduction gear such as a worm gear, gears, or other system. This single actuator forms, on the one hand, the guidance system 6, i.e., it guides the movement, in this case the rotation, of the second structural element 3 relative to the first structural element 2, and on the other hand, the compression system 8, i.e., it applies pressure between the first and second structural elements 2 and 3 to ensure thermal junction between them in the closed position where the single actuator then presses on the second structural element 2, the single actuator being active.

[0101] As shown in Figure 11, the single actuator forming the guide system 6 and compression system 8 is, for example, made up of a motor and gearbox assembly M&R. Here again, the actuator is active.

[0102] As shown in Figure 12, the single actuator comprises, for example, a motor M and a "grasshopper" type reduction system 40, also known as a "four-bar linkage" or "bar linkage." The reduction system 40 allows the actuator to reach a near-singular position upon contact in the closed position with an alignment of the two bars, which significantly increases the pressure for the same actuator torque.

[0103] As shown in Figure 13, the guidance system 6 includes, for example, an elastic element tending to drive the first and second structural elements 2, 3 towards the closed position. The first actuator forming this elastic element thus comprises a spring 41, which is symbolically represented around the axis of rotation corresponding to the pivot 10. The spring can have a relatively low torque and energy. The second actuator of the compression system 8 is active and, in this example, comprises a front cam 42, one end of which has a surface forming an angle with respect to the plane of the second structural element 3. The first structural element 2 has an opening 43 for the insertion of the front cam 42. The rotation of this front cam 42 by a motor M allows it to contact a suitable surface of the second structural element 3 and to apply pressure.

[0104] The example in Figure 14 differs from that in Figure 13 in that the second structural element 3 includes, for example, a rod 44 perpendicular to the plane of the second element structural element 3 and provided with a transverse opening 45 with an inclined surface. In the closed position, this rod 44 is inserted into the corresponding opening 43. The second actuator comprises, for example, a motor M and a rod 46 having an end 47 with a shape complementary to the transverse opening 45, such that actuation of the rod 46 by the motor M allows its end 47 to engage in the transverse opening 45 in the closed position in order to perform the desired compression between the first and second structural elements 2 and 3.

[0105] As shown in Figure 15, the compression system 8 includes, for example, a rivet 48 made of shape-memory material which is held in a hook 49 of the second structural element 3 in the closed position. The shape-memory material of the rivet 48 is then activated to pressurize the first and second structural elements 2 and 3. In this case, the second actuator is necessarily active.

[0106] As shown in Figure 16, the second actuator of the compression system 8 comprises, for example, another torsion spring 50, connected to a lever 51 at the end of which is a circular roller 52 that can roll freely on its own axis, being pivot-mounted at the end of the lever 51. The axis of rotation of the guide system 6 is equipped with a circular cam 53 with a flat surface. During deployment between the open and closed positions, the circular roller 52 of the lever 51 rolls on the cam 53, first in the circular portion and then, at the end of deployment, on the flat surface, and it is then that it presses and compresses the second structural element 3 against the first structural element 2.

[0107] As shown in Figure 17, the pressurization is for example carried out passively by magnets 54, namely a magnet 54a disposed on the first structural element 2 and a magnet 54b disposed on the second structural element 3 and configured so as to arrive in their zone of influence at the end of deployment and to attract each other into the closed position.

[0108] In all the examples illustrated in Figures 1 to 17, the number of parts involved in the thermal coupling path is limited. Indeed, once in the closed position, i.e., deployed, the heat flow passes from the first structural element 2 to the second structural element 3 via a reduced thermal path including, for example, a single thermal seal 5, which maximizes performance.

[0109] Furthermore, the use of thermal seal 5 makes it possible, for example, to compensate for microscopic and macroscopic defects, thus ensuring the desired contact surface and achieving a sufficient pressure level for the thermal seal to be effective, with a reduced thickness.

[0110] It should be noted that, apart from the rotation illustrated in the figures, all sorts of movements are possible to go from the open to the closed position. In particular, pivot 10 can, for example, be replaced by a slide. The movement between the open and closed positions is, for example, a translation rather than a rotation.

[0111] Finally, the first and second structural elements 2 and 3 may be thermally coupled, or not, in the open position, before deployment, although the examples illustrated in figures 1 to 17 show an absence of thermal coupling of the first and second structural elements 2 and 3 in the open position.

[0112] The system according to this disclosure is for example automatic, and can be active, with a motor for example, or passive, with a spring for example.

Claims

Demands

1. Thermal junction system (1) comprising first and second structural elements (2, 3) and establishing thermal junction between a first interface (2a) of the first structural element (2) and a second interface (3a) of the second structural element (3), the first and second structural elements being intended to be integrated into a spacecraft, characterized in that the first and second structural elements (2, 3) are in the form of extended flat panels with the first and second interfaces (2a, 3a) being in the form of flat surfaces, the thermal junction system (1) comprising: a mechanical guidance system (6) configured to bring the first and second movable structural elements (2, 3) closer together from at least an open position where the first and second interfaces (2a, 3a) are separated from each other and a closed position where the first and second interfaces (2a,3a) are pressed together to be thermally connected, a thermal seal (5) extending over one and / or the other of the first and second interfaces (2a, 3a), the thermal seal (5) comprising a dry material or thermal paste and having a thermal conductance greater than or equal to 1000 W / m, 2 / K, a triggering system (7) configured to trigger at least one movement of the first and second structural elements (2, 3) from the open position to the closed position, a compression system (8) configured at least to compress the first and second interfaces (2a, 3a) against each other in the closed position.

2. System (1) according to claim 1, wherein the mechanical guidance system and the compression system are of the passive type.

3. System (1) according to any one of the preceding claims, wherein the first and / or respectively second structural elements comprise first and / or respectively second heat transfer systems (9) flush at their first and / or respectively second interface (2a, 3a).

4. System (1) according to any one of the preceding claims, wherein said open position before triggering corresponds to a compact configuration at launch.

5. System (1) according to any one of the preceding claims, wherein the triggering system (7) comprises at least one holding and releasing mechanism.

6. System (1) according to any one of the preceding claims, wherein the guidance system (6) comprises an elastic element tending to bring the first and second structural elements (2, 3) closer to the closed position.

7. System (1) according to any one of the preceding claims, wherein the compression system (8) comprises a second actuator driven by an elastic element tending to exert the compression force.

8. System (1) according to any one of the preceding claims, wherein the first structural element (2) is a structural panel of the spacecraft and the second structural element (3) is a radiator of the spacecraft.

9. System (1) according to any one of the preceding claims, wherein the guidance system (6) comprises a pivot (10) with an axis of rotation, the displacement of the second structural element (3) from the open position to the closed position comprising a rotation about the axis of rotation of the pivot (10).

10. System (1) according to any one of the preceding claims, wherein the first and second structural elements are rotationally movable relative to each other.

11. System (1) according to claim 10, wherein the guide system (6) comprises a delay mechanism configured to maintain the compression system (8) in a raised position, then to release the compression system (8) in the closed position, the delay mechanism being in the form of a cam (12) integral with the second structural element (3), the cam (12) comprising a circular guide surface (13) followed by a housing (14) receiving a roller (17) in the closed position, the roller belonging to the compression system (8) and driving a support arm (18) configured to be able to bear against the second structural element (3) in the closed position, the support arm (18) being rotationally movable relative to the first structural element (2).

12. System (1) according to the preceding claim, wherein the support arm (18) is configured to pass through a passage (19) made in the second structural element (3) when the support arm (18) is in its raised position.

13. System (1) according to claim 11 or 12, wherein the compression system (8) comprises: a motor arm (16) movable in rotation relative to the first structural element (2), the motor arm (16) being connected to the roller (17), and a force multiplier arm (15) articulated on one side relative to the support arm (18) and on the other side relative to the motor arm (16).

14. System according to any one of the preceding claims, characterized in that it is devoid of a hydraulic actuator.

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