Deployable light shield based on spatial four-bar mechanism

Abstract

The invention provides an expandable light shield based on a spatial four-bar mechanism, which is used for solving the technical problems that the existing expandable light shield is low in precision and low in rigidity after being expanded, and the existing rigid light shield can only be applied to a space optical system with a smaller size. According to the deployable light shield based on the spatial four-connecting-rod mechanism, a spatial over-constrained Bennett mechanism or a spherical 4R connecting-rod mechanism or a planar four-connecting-rod mechanism serves as an unfolding driving mechanism of the planar light shield, and the planar light shield can be folded in the launching process of a rocket in cooperation with the pressing base and the locking device; therefore, a smaller space volume is realized; when a rocket reaches an on-orbit expected position, the two groups of spatial four-bar mechanisms are matched with the driving of the elastic driving hinges on the premise that motion constraint conditions in corresponding spaces are met, so that the planar light shield is unfolded from a completely folded state and locked, and the planar light shield also has relatively high precision and structural rigidity in a working state.

Description

Technical Field

[0001] The invention relates to a deployable sunshade, in particular to a deployable sunshade based on a spatial four-bar linkage mechanism. Background Art

[0002] With the increasing demand for space situational awareness, the aperture of space optical cameras has gradually increased, and the size of the components compatible with space optical cameras has also increased accordingly. Among them, the size of the sunshade, as the core component for realizing the functions of space optical cameras, has also increased significantly. At present, most of the large-sized sunshades used in space orbit are one-piece structures and do not have the function of being deployable. However, due to the limitation of rocket space, the large envelope volume of large-sized sunshades has obvious defects during rocket launch. Therefore, applying the idea of ​​foldability to large-sized sunshades is a new idea to solve this problem.

[0003] In recent years, many researchers have proposed some deployable sunshade solutions, mainly including sunshade solutions that combine rigid skeletons, elastic materials, inflatable composite materials and other new materials with flexible composite materials. However, the deployable sunshades based on the above solutions have low precision after deployment and have the limitation of low rigidity. Space optical cameras require rigid sunshades with higher rigidity. Existing solutions include screw-driven cylindrical deployment, but most of them are applied to smaller-sized space optical systems. Summary of the invention

[0004] The purpose of the present invention is to solve the limitations of the existing deployable sunshade, such as low precision and low rigidity after deployment, and the technical problem that the existing rigid sunshade can only be applied to smaller-sized space optical systems, and to provide a deployable sunshade based on a spatial four-bar linkage mechanism.

[0005] In order to achieve the above object, the technical solution provided by the present invention is as follows:

[0006] A deployable sunshade based on a spatial four-bar linkage, characterized in that:

[0007] It includes a plane sunshade, a bottom plate, two elastic driving hinges and two sets of spatial four-bar linkages;

[0008] The planar light shield comprises a planar substrate, fixed side plates respectively vertically connected to both sides of the planar substrate, and a plurality of light-shielding strips laterally arranged on the planar substrate;

[0009] The positions near the bottom on the outer side walls of the two fixed side panels are respectively connected to the upper surfaces of both sides of the bottom panel through elastic driving hinges; an optical through hole is axially opened on the bottom panel, and a plurality of light blocking strips are located on the side of the planar substrate facing the bottom panel;

[0010] The spatial four-bar linkage mechanism comprises a first support rod, a second support rod, an elastic hinge, a first hinge and a second hinge; one end of the first support rod and the second support rod are connected by an elastic hinge, the other end of the first support rod is hinged to the outer wall of the fixed side plate on one side by the first hinge, and the other end of the second support rod is hinged to the upper surface of the bottom plate on the same side by the second hinge; the two sets of spatial four-bar linkage mechanisms have the same structure and are symmetrically arranged on both sides of the plane sunshade;

[0011] The two spatial four-bar linkages and the two fixed side plates and the corresponding positions on both sides of the bottom plate together constitute two symmetrically arranged spatial over-constrained Bennett mechanisms, or constitute two symmetrically arranged spatial spherical 4R linkage mechanisms, or constitute two symmetrically arranged planar four-bar linkages;

[0012] The outer side walls of the two fixed side plates are respectively provided with clamping seats, and the corresponding positions of the bottom plate are provided with two locking devices, which are used to lock the plane sunshade through the clamping seats and the corresponding locking devices when the plane sunshade is in the folded state.

[0013] Furthermore, the constraint condition for the motion of the spatial overconstrained Bennett mechanism in space is:

[0014] l1=l3,l2=l4

[0015] α1=α3,α2=α4

[0016] β1=β3,β2=β4

[0017] l1 / sin(β1)=l3 / sin(β3), l2 / sin(β2)=l4 / sin(β4).

[0018] Among them, l1 is the offset between the first hinge and the elastically driven hinge, l2 is the offset between the elastically driven hinge and the second hinge, l3 is the offset between the second hinge and the elastic hinge, and l4 is the offset between the elastic hinge and the first hinge; α1 is the angle between the planar sunshade and the base plate around the central axis of the elastically driven hinge, α2 is the angle between the base plate and the second support rod around the central axis of the second hinge, α3 is the angle between the second support rod and the first support rod around the central axis of the elastic hinge, and α4 is the angle between the first support rod and the planar sunshade around the central axis of the first hinge; β1 is the angle between the central axis of the elastically driven hinge and the central axis of the first hinge around their common normal, β2 is the angle between the central axis of the second hinge and the central axis of the elastically driven hinge around their common normal, β3 is the angle between the central axis of the elastic hinge and the central axis of the second hinge around their common normal, and β4 is the angle between the central axis of the first hinge and the central axis of the elastic hinge around their common normal.

[0019] Furthermore, the constraint condition for the movement of the spherical 4R linkage mechanism in space is:

[0020] l1=l4=l2=l3=r

[0021] α1=α3,α2=α4

[0022] α1+α2+α3+α4=450°

[0023] Among them, r is the radius of the sphere formed by the elastic driven hinge, the elastic hinge, the first hinge and the second hinge, l1 is the distance from the center point of the first hinge to the center of the sphere, l2 is the distance from the center point of the elastic driven hinge to the center of the sphere, l3 is the distance from the center point of the second hinge to the center of the sphere, and l4 is the distance from the center point of the elastic hinge to the center of the sphere; α1 is the angle between the plane sunshade and the base plate around the central axis of the elastic driven hinge, α2 is the angle between the base plate and the second support rod around the central axis of the second hinge, α3 is the angle between the second support rod and the first support rod around the central axis of the elastic hinge, and α4 is the angle between the first support rod and the plane sunshade around the central axis of the first hinge.

[0024] Furthermore, the constraint condition of the planar four-bar linkage moving in space is:

[0025] l1+l4=l2+l3

[0026] α1+α2+α3+α4=360°

[0027] α1=α3,α4=α2

[0028] Among them, l1 is the offset between the first hinge and the elastic driven hinge, l2 is the offset between the elastic driven hinge and the second hinge, l3 is the offset between the second hinge and the elastic hinge, and l4 is the offset between the elastic hinge and the first hinge; α1 is the angle between the planar sunshade and the base plate around the central axis of the elastic driven hinge, α2 is the angle between the base plate and the second support rod around the central axis of the second hinge, α3 is the angle between the second support rod and the first support rod around the central axis of the elastic hinge, and α4 is the angle between the first support rod and the planar sunshade around the central axis of the first hinge.

[0029] Further, the elastic drive hinge is a vortex spring locking hinge;

[0030] The elastic hinge is a torsion spring pin hinge;

[0031] The first hinge and the second hinge are both pin hinges.

[0032] Further, the elastic drive hinge is a sliding groove type vortex spring locking hinge, comprising a first fixing seat, a second fixing seat, a male hinge, a female hinge, a vortex spring, a clamping rod, a locking pin and a clamping torsion spring;

[0033] The first fixing seat is installed on the upper surface of the base, and the second fixing seat is installed on the outer side wall of the fixed side plate;

[0034] The female hinge is arranged on the first fixed seat and connected to the fixed end of the spiral spring, and the male hinge is arranged on the second fixed seat and connected to the movable end of the spiral spring, so as to make the male hinge rotate along the motion track of the movable end of the spiral spring;

[0035] A fixed shaft is installed on the female hinge, and a compression torsion spring is installed on the fixed shaft;

[0036] One end of the clamping rod is rotatably connected to the fixed shaft, and the other end is fixedly connected to the locking pin, and the locking pin is arranged corresponding to the male hinge;

[0037] A sliding groove is provided on the male hinge at a position corresponding to the locking pin, and a protrusion is provided on the male hinge below the sliding groove. The working end of the compression torsion spring presses against the locking pin, so that the locking pin cooperates with the sliding groove or the protrusion when the male hinge moves to different positions.

[0038] Further, the locking device includes a base and a locking rod arranged on the base;

[0039] A pyrotechnic detonating device is arranged in the base;

[0040] The pressing seat is provided with a locking hole matched with the locking rod. After the remote control pyrotechnic detonating device is detonated, the locking rod is separated from the base, thereby realizing the separation of the locking device from the pressing seat.

[0041] Furthermore, the unfolding angle of the elastically driven hinge is 90 degrees, which is used to enable the planar sunshade to be folded 90 degrees.

[0042] Furthermore, the angle between the planar substrate and the upper surface of the light-blocking strip is an obtuse angle, and each angle decreases from top to bottom; the width of the fixed side plate increases from top to bottom; the inner side walls of the two fixed side plates are respectively abutted against both ends of the multiple light-blocking strips.

[0043] Furthermore, the connection position between the first support rod and the fixed side plate is higher than the connection position between the elastic drive hinge and the fixed side plate.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] 1. The present invention provides a deployable sunshade based on a spatial four-bar linkage, which uses a spatial over-constrained Bennett mechanism or a spherical 4R linkage mechanism or a planar four-bar linkage mechanism as the deployment drive mechanism of the planar sunshade. In conjunction with a clamping seat and a locking device, the rocket can fold and fold the planar sunshade during launch to achieve a smaller spatial volume. When the rocket reaches the expected on-orbit position, the two sets of spatial four-bar linkage mechanisms, under the premise of satisfying the motion constraints in the corresponding space, cooperate with the drive of the elastic drive hinge to deploy and lock the planar sunshade from a fully folded state, so that it has higher precision and structural rigidity in the working state, providing a new idea for the on-orbit application of large-size sunshades and filling the gap of large-size and high-rigidity sunshades.

[0046] 2. The present invention provides an expandable light shield based on a spatial four-bar linkage. In the fully retracted state, an aerospace pyrotechnic locking device and a clamping seat are used to securely connect the flat light shield to the base plate, thereby ensuring that the light shield can still meet the required rigidity in the fully locked state during the launch process. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 It is a structural schematic diagram of a first embodiment of a deployable sunshade based on a spatial four-bar linkage mechanism of the present invention;

[0048] Figure 2 Schematic diagram of various parameters of the spatial over-constrained Bennett mechanism in the first embodiment of the present invention when the spatial motion constraint condition is satisfied;

[0049] Figure 3 It is a schematic diagram of the structure of the elastically driven hinge in an embodiment of the present invention;

[0050] Figure 4 Schematic diagram of the locking process of the vortex spring locking hinge in the first embodiment of the present invention;

[0051] Figure 5 Schematic diagram of the unfolding process of the planar light shield in the first embodiment of the present invention Figure 1 ;

[0052] Figure 6 Schematic diagram of the unfolding process of the planar light shield in the first embodiment of the present invention Figure 2 ;

[0053] Figure 7 It is a structural schematic diagram of a second embodiment of a deployable sunshade based on a spatial four-bar linkage mechanism of the present invention;

[0054] Figure 8 Schematic diagram of parameters of various parts when the spherical 4R linkage mechanism in the second embodiment of the present invention satisfies the motion constraint conditions in space;

[0055] Fig. 9Schematic diagram of the unfolding process of the planar light shield in the second embodiment of the present invention Figure 1 ;

[0056] Fig.10 Schematic diagram of the unfolding process of the planar light shield in the second embodiment of the present invention Figure 2 ;

[0057] Fig.11 This is a structural schematic diagram of a third embodiment of a deployable sunshade based on a spatial four-bar linkage mechanism according to the present invention;

[0058] Fig.12 Schematic diagram of parameters of various parts of the planar four-bar linkage in the third embodiment of the present invention when the planar four-bar linkage meets the motion constraint conditions in space;

[0059] Fig.13 Schematic diagram of the unfolding process of the planar light shield in the third embodiment of the present invention Figure 1 ;

[0060] Fig.14 Schematic diagram of the unfolding process of the planar light shield in the third embodiment of the present invention Figure 2 .

[0061] The specific reference numerals are as follows:

[0062] 1. Plane sunshade; 11. Plane substrate; 12. Fixed side panel; 13. Light shielding strip; 2. Bottom plate; 3. Elastic drive hinge; 31. First fixed seat; 32. Second fixed seat; 33. Male hinge; 34. Female hinge; 35. Volute spring; 36. Clamping rod; 37. Locking pin; 38. Clamping torsion spring; 4. First support rod; 5. Second support rod; 6. Elastic hinge; 7. First hinge; 8. Second hinge; 9- Clamping seat; 10- Locking device. DETAILED DESCRIPTION

[0063] In order to make the advantages and features of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0064] Embodiment 1

[0065] like Figure 1 As shown, a deployable sunshade based on a spatial four-bar linkage mechanism comprises a planar sunshade 1, a base plate 2, two elastic drive hinges 3, two sets of spatial four-bar linkage mechanisms, a pressing seat 9 and a locking device 10.

[0066] The planar sunshade 1 includes a planar substrate 11, fixed side panels 12 vertically connected to both sides of the planar substrate 11, and a plurality of light-shielding strips 13 arranged transversely on the planar substrate 11, and the two ends of the plurality of light-shielding strips 13 are respectively in contact with the inner side walls of the two planar substrates 11. The angle between the planar substrate 11 and the upper surface of the light-shielding strip 13 is an obtuse angle, and each angle decreases from top to bottom. Accordingly, the width of the fixed side panels 12 increases from top to bottom. The angle between the planar substrate 11 and the upper surface of the lower light-shielding strip 13 is greater than the angle between the planar substrate 11 and the upper surface of the upper light-shielding strip 13, which can better suppress stray light.

[0067] The positions near the bottom on the outer side walls of the two fixed side panels 12 are connected to the upper surfaces on both sides of the bottom plate 2 through elastically driven hinges 3; the unfolding angle of the elastically driven hinges 3 is 90 degrees, which is used to enable the plane light shield 1 to be folded 90 degrees. An optical through hole is axially opened on the bottom plate 2 as a light through hole for the optical camera; a plurality of light shielding strips 13 are located on the side of the plane substrate 11 facing the bottom plate 2, which are used to shield stray light in the space. At the same time, this arrangement can make the light shielding strips 13 located inside the plane light shield 1 when the plane light shield 1 is in the folded state, effectively avoiding interference contact with the light shielding strips 13.

[0068] The spatial four-bar linkage mechanism includes a first support rod 4, a second support rod 5, an elastic hinge 6, a first hinge 7, and a second hinge 8; one end of the first support rod 4 and the second support rod 5 are linked by an elastic hinge 6, the other end of the first support rod 4 is hinged to the outer wall of the fixed side plate 12 on one side by the first hinge 7, and the other end of the second support rod 5 is hinged to the upper surface of the bottom plate 2 on the same side by the second hinge 8; the two groups of spatial four-bar linkage mechanisms have the same structure and are symmetrically arranged on both sides of the plane sunshade 1, that is, the other end of the other first support rod 4 is hinged to the outer wall of the fixed side plate 12 on the other side by the first hinge 7, and the other end of the other second support rod 5 is hinged to the upper surface of the bottom plate 2 on the corresponding side by the second hinge 8. In this embodiment, the elastic hinge 6 adopts a torsion spring pin hinge, the first hinge 7 and the second hinge 8 both adopt traditional pin hinges, and the first hinge 7 and the second hinge 8 do not add torsion springs, so that redundant driving can be avoided. At the same time, the connection position of the first support rod 4 and the fixed side panel 12 needs to be higher than the connection position of the vortex spring locking hinge 3 and the fixed side panel 12, that is, the first support rod 4 is not parallel to the bottom plate 2 when in the fully folded state to avoid the unfolding movement being stuck due to the dead point of the mechanism.

[0069] Two sets of spatial four-bar linkages and the corresponding positions on both sides of the two fixed side panels 12 and the bottom plate 2 together constitute two symmetrically arranged single-degree-of-freedom spatial over-constrained Bennett mechanisms. This embodiment adopts the spatial over-constrained Bennett mechanism as the unfolding drive mechanism of the planar light shield 1, which, in conjunction with the clamping seat and the locking device, can enable the rocket to fold and fold the planar light shield 1 during the launch process to achieve a smaller spatial volume; at the same time, when the rocket reaches the expected on-orbit position, the two spatial over-constrained Bennett mechanisms are driven by the elastic driving hinge 3 to unfold and lock the planar light shield 1 from a fully folded state, providing a new idea for the on-orbit application of large-size light shields.

[0070] like Figure 2 As shown, the four revolute pairs in the spatial over-constrained Bennett mechanism are the elastic drive hinge 3, the elastic hinge 6, the first hinge 7 and the second hinge 8, and the central axes of the four revolute pairs are parallel to each other in space. Define l1 as the offset between the first hinge 7 and the elastic drive hinge 3, l2 as the offset between the elastic drive hinge 3 and the second hinge 8, l3 as the offset between the second hinge 8 and the elastic hinge 6, and l4 as the offset between the elastic hinge 6 and the first hinge 7; α1 is the angle between the plane sunshade 1 and the bottom plate 2 around the central axis of the elastic drive hinge 3, α2 is the angle between the bottom plate 2 and the second support rod 5 around the central axis of the second hinge 8, and α3 is the angle between the second support rod 5 and the first support rod 4 around the central axis of the elastic hinge 6. α4 is the angle between the first support rod 4 and the plane sunshade 1 around the central axis of the first hinge 7; β1 is the angle between the central axis of the elastically driven hinge 3 and the central axis of the first hinge 7 around the common normal of the two; β2 is the angle between the central axis of the second hinge 8 and the central axis of the elastically driven hinge 3 around the common normal of the two; β3 is the angle between the central axis of the elastic hinge 6 and the central axis of the second hinge 8 around the common normal of the two; β4 is the angle between the central axis of the first hinge 7 and the central axis of the elastic hinge 6 around the common normal of the two. In order to achieve the fully folded and compressed state of the sunshade and the expected angle when unfolded, the above parameters should meet the following constraints:

[0071] l1=l3,l2=l4

[0072] α1=α3,α2=α4

[0073] β1=β3,β2=β4

[0074] l1 / sin(β1)=l3 / sin(β3), l2 / sin(β2)=l4 / sin(β4).

[0075] The above constraints are the constraints for the motion of the spatial overconstrained Bennett mechanism in space.

[0076] A clamping seat 9 is provided on the outer side wall of the two fixed side panels 12, respectively, and two locking devices 10 are provided at corresponding positions on the bottom plate 2, which are used to lock the plane light shield 1 in the folded state through the clamping seat 9 and the corresponding locking device 10. The locking device 10 and the clamping seat 9 can use the pyrotechnic unlocking device or memory alloy unlocking device commonly used in aerospace. Specifically, the locking device 10 includes a base and a locking rod arranged on the base, and a pyrotechnic detonating device is provided in the base. A locking hole adapted to the locking rod is provided on the clamping seat 9. When the light shield needs to be opened, the pyrotechnic detonating device is remotely controlled to detonate, so that the locking rod is separated from the base, thereby realizing the separation of the locking device 10 from the clamping seat 9.

[0077] like Figure 3 As shown, the elastic drive hinge 3 in this embodiment is a sliding groove type vortex spring locking hinge. In other embodiments of the present invention, other types of existing elastic drive hinges may also be used. The sliding groove type vortex spring locking hinge includes a first fixed seat 31, a second fixed seat 32, a male hinge 33, a female hinge 34, a vortex spring 35, a clamping rod 36, a locking pin 37 and a clamping torsion spring 38. The first fixed seat 31 is installed on the upper surface of the base, and the second fixed seat 32 is installed on the outer side wall of the fixed side plate 12; the female hinge 34 is arranged on the first fixed seat 31 and connected to the fixed end of the vortex spring 35, and the male hinge 33 is arranged on the second fixed seat 32 and connected to the movable end of the vortex spring 35, so as to make the male hinge 33 rotate along the motion trajectory of the movable end of the vortex spring 35. A fixed shaft is installed on the female hinge 34, and a compression torsion spring 38 is installed on the fixed shaft; one end of the compression rod 36 is rotatably connected to the fixed shaft, and the other end is fixedly connected to the locking pin 37, and the locking pin 37 is arranged corresponding to the male hinge 33. When the male hinge 33 is locked, a sliding groove is provided on it at a position corresponding to the locking pin 37, and a protrusion is arranged on the male hinge 33 at a position below the sliding groove. The working end of the compression torsion spring 38 presses against the locking pin 37, and is used to make the locking pin 37 slide into the sliding groove for mechanical limit locking under the action of the compression torsion spring 38 when the male hinge 33 is in the initial state, and when the male hinge 33 moves away from the initial state following the scroll spring 35, the locking pin 37 is pressed against the protrusion of the male hinge 33 under the action of the compression torsion spring 38.

[0078] The locking process of the vortex spring locking hinge is as follows Figure 4As shown, when the plane light shield 1 is in the folded state, the volute spring 35 continuously provides the volute spring locking hinge with a driving torque in the unfolding direction, but at this time, due to the action of the locking device 10, the volute spring locking hinge is in a non-expanded state. When the plane light shield 1 reaches the expected working position, the locking device 10 is unlocked, and the plane light shield 1 is driven to unfold under the combined action of the torque of the volute spring 35 and the torque of the compression torsion spring 38, and at the same time, the locking pin 37 is always pressed on the male hinge 33 under the action of the compression torsion spring 38. When the plane light shield 1 is unfolded to the predetermined working position, the locking pin 37 moves to the slide slot position of the male hinge 33, enters the slide slot under the action of the compression torsion spring 38, and is mechanically limited and locked.

[0079] like Figure 5 , Figure 6 As shown, it is a schematic diagram of the unfolding process of the planar sunshade 1 using two symmetrically arranged space-overconstrained Bennett mechanisms. When the planar sunshade 1 is in a fully folded state, that is, the planar sunshade 1 is fixedly connected to the base plate 2 through the clamping seat 9 and the locking device 10, and the first support rod 4 and the second support rod 5 are folded. When the planar sunshade 1 reaches the predetermined working position, the locking device 10 is unlocked to eliminate the fixed constraint. At this time, the volute spring 35 located at the root and the compression torsion spring 38 located between the two support rods provide the unfolding driving torque for the two space-overconstrained Bennett mechanisms, driving the two space-overconstrained Bennett mechanisms to unfold according to their own motion trajectory. After unfolding to the predetermined working position, the first support rod 4 and the second support rod 5 are located at the dead point position of the same line, and at the same time, the locking pin 37 in the root elastic drive hinge 3 slides into the slide groove of the male hinge 33 to realize the locking of the elastic drive hinge 3. At this time, the planar sunshade 1 is in a fully unfolded and locked structural state.

[0080] Embodiment 2

[0081] The difference between this embodiment and the first embodiment is that Figure 7 As shown, in this embodiment, two sets of spatial four-bar linkage mechanisms and the two fixed side plates 12 and the corresponding positions on both sides of the bottom plate 2 together constitute two symmetrically arranged single-degree-of-freedom spherical 4R linkage mechanisms, and the spherical 4R linkage mechanisms are used as the unfolding driving mechanism of the planar sunshade 1.

[0082] like Figure 8As shown, the four revolute pairs in the spherical 4R linkage mechanism are the elastic drive hinge 3, the elastic hinge 6, the first hinge 7 and the second hinge 8. The central axes of the four revolute pairs are parallel to each other in space and form a sphere. Define r as the radius of the sphere, l1 as the distance from the center point of the first hinge 7 to the center of the sphere, l2 as the distance from the center point of the elastic drive hinge 3 to the center of the sphere, l3 as the distance from the center point of the second hinge 8 to the center of the sphere, and l4 as the distance from the center point of the elastic hinge 6 to the center of the sphere; α1 is the angle between the plane sunshade 1 and the bottom plate 2 around the center axis of the elastic drive hinge 3, α2 is the angle between the bottom plate 2 and the second support rod 5 around the center axis of the second hinge 8, α3 is the angle between the second support rod 5 and the first support rod 4 around the center axis of the elastic hinge 6, and α4 is the angle between the first support rod 4 and the plane sunshade 1 around the center axis of the first hinge 7. In order to achieve the fully folded and compressed state of the sunshade and the expected angle when unfolded, the above parameters should meet the following constraints:

[0083] l1=l4=l2=l3=r

[0084] α1=α3,α2=α4

[0085] α1+α2+α3+α4=450°

[0086] The above constraints are the constraints for the movement of the spherical 4R linkage mechanism in space.

[0087] like Fig. 9 , Fig.10 FIG. 2 is a schematic diagram of the unfolding process of the planar sunshade 1 using two symmetrically arranged spherical 4R connecting rod mechanisms.

[0088] Embodiment 3

[0089] The difference between this embodiment and the first embodiment is that Fig.11 As shown, in this embodiment, two sets of spatial four-bar linkages and two fixed side plates 12 and corresponding positions on both sides of the bottom plate 2 together constitute two symmetrically arranged single-degree-of-freedom planar four-bar linkages, and the planar four-bar linkages are used as the unfolding drive mechanism of the planar sunshade 1.

[0090] like Fig.12As shown, the four revolute pairs of the planar four-bar linkage are the elastic drive hinge 3, the elastic hinge 6, the first hinge 7 and the second hinge 8, and the central axes of the four revolute pairs are parallel to each other in space. Define l1 as the offset between the first hinge 7 and the elastic drive hinge 3, l2 as the offset between the elastic drive hinge 3 and the second hinge 8, l3 as the offset between the second hinge 8 and the elastic hinge 6, and l4 as the offset between the elastic hinge 6 and the first hinge 7; α1 is the angle between the planar sunshade 1 and the bottom plate 2 around the central axis of the elastic drive hinge 3, α2 is the angle between the bottom plate 2 and the second support rod 5 around the central axis of the second hinge 8, α3 is the angle between the second support rod 5 and the first support rod 4 around the central axis of the elastic hinge 6, and α4 is the angle between the first support rod 4 and the planar sunshade 1 around the central axis of the first hinge 7. In order to achieve the fully folded and compressed state of the sunshade and the expected angle when unfolded, the above parameters should meet the following constraints:

[0091] l1+l4=l2+l3

[0092] α1+α2+α3+α4=360°

[0093] α1=α3,α4=α2

[0094] The above constraints are the constraints for the motion of the planar four-bar linkage in space.

[0095] like Fig.13 , Fig.14 FIG. 2 is a schematic diagram of the unfolding process of the planar sunshade 1 using two symmetrically arranged planar four-bar linkages.

[0096] The above description is only used to illustrate the technical solution of the present invention rather than to limit it. For ordinary professional and technical personnel in the field, the specific technical solution recorded in the above embodiment can be modified, or some of the technical features therein can be replaced by equivalents, and these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution protected by the present invention.

Claims

1. A deployable sunshade based on a spatial four-bar linkage, characterized in that: It comprises a plane light shield (1), a bottom plate (2), two elastic drive hinges (3) and two sets of spatial four-bar linkages; The planar light shield (1) comprises a planar substrate (11), fixed side plates (12) respectively vertically connected to both sides of the planar substrate (11), and a plurality of light shielding strips (13) transversely arranged on the planar substrate (11); Positions close to the bottom on the outer side walls of the two fixed side panels (12) are respectively connected to the upper surfaces of both sides of the bottom panel (2) via elastically driven hinges (3); an optical through hole is axially opened on the bottom panel (2), and a plurality of light blocking strips (13) are located on the side of the planar substrate (11) facing the bottom panel (2); The spatial four-bar linkage mechanism comprises a first support rod (4), a second support rod (5), an elastic hinge (6), a first hinge (7) and a second hinge (8); one end of the first support rod (4) and the second support rod (5) are linked by the elastic hinge (6), the other end of the first support rod (4) is hinged to the outer wall of a fixed side plate (12) on one side by the first hinge (7), and the other end of the second support rod (5) is hinged to the upper surface of the bottom plate (2) on the same side by the second hinge (8); the two sets of spatial four-bar linkage mechanisms have the same structure and are symmetrically arranged on both sides of the plane sunshade (1); The two spatial four-bar linkages, the two fixed side plates (12) and the corresponding positions on both sides of the bottom plate (2) together form two symmetrically arranged spatial over-constrained Bennett mechanisms, or form two symmetrically arranged spatial spherical 4R linkage mechanisms, or form two symmetrically arranged planar four-bar linkages; A clamping seat (9) is respectively provided on the outer side walls of the two fixed side plates (12), and two locking devices (10) are provided at corresponding positions on the bottom plate (2) for enabling the planar sunshade (1) to be locked by the clamping seat (9) and the corresponding locking devices (10) when the planar sunshade (1) is in a folded state.

2. The deployable sunshade based on a spatial four-bar linkage according to claim 1, characterized in that: The constraint conditions for the motion of the spatial overconstrained Bennett mechanism in space are: l1＝l3，l2＝l4 α1＝α3，α2＝α4 β1＝β3，β2＝β4 l1 / sin(β1)=l3 / sin(β3), l2 / sin(β2)=l4 / sin(β4). Wherein, l1 is the offset between the first hinge (7) and the elastically driven hinge (3), l2 is the offset between the elastically driven hinge (3) and the second hinge (8), l3 is the offset between the second hinge (8) and the elastic hinge (6), and l4 is the offset between the elastic hinge (6) and the first hinge (7); α1 is the angle between the plane sunshade (1) and the bottom plate (2) around the central axis of the elastically driven hinge (3), α2 is the angle between the bottom plate (2) and the second support rod (5) around the central axis of the second hinge (8), and α3 is the angle between the second support rod (5) and the first support rod (4) around the central axis of the elastically driven hinge (3). The invention relates to an angle between the central axis of the elastic drive hinge (3) and the central axis of the first hinge (7), α4 is the angle between the first support rod (4) and the plane sunshade (1) around the central axis of the first hinge (7); β1 is the angle between the central axis of the elastic drive hinge (3) and the central axis of the first hinge (7) around the common normal of the two, β2 is the angle between the central axis of the second hinge (8) and the central axis of the elastic drive hinge (3) around the common normal of the two, β3 is the angle between the central axis of the elastic hinge (6) and the central axis of the second hinge (8) around the common normal of the two, and β4 is the angle between the central axis of the first hinge (7) and the central axis of the elastic hinge (6) around the common normal of the two.

3. The deployable sunshade based on a spatial four-bar linkage according to claim 1, characterized in that: The constraint conditions for the motion of the spherical 4R linkage mechanism in space are: l1＝l4＝l2＝l3＝r α1＝α3，α2＝α4 α1+α2+α3+α4＝450° Wherein, r is the radius of the sphere formed by the elastic drive hinge (3), the elastic hinge (6), the first hinge (7) and the second hinge (8); l1 is the distance from the center point of the first hinge (7) to the center of the sphere; l2 is the distance from the center point of the elastic drive hinge (3) to the center of the sphere; l3 is the distance from the center point of the second hinge (8) to the center of the sphere; l4 is the distance from the center point of the elastic hinge (6) to the center of the sphere; α1 is the angle between the plane sunshade (1) and the base plate (2) around the center axis of the elastic drive hinge (3); α2 is the angle between the base plate (2) and the second support rod (5) around the center axis of the second hinge (8); α3 is the angle between the second support rod (5) and the first support rod (4) around the center axis of the elastic hinge (6); and α4 is the angle between the first support rod (4) and the plane sunshade (1) around the center axis of the first hinge (7).

4. The deployable sunshade based on a spatial four-bar linkage according to claim 1, characterized in that: The constraint conditions for the motion of the planar four-bar linkage in space are: Wherein, l1 is the offset between the first hinge (7) and the elastically driven hinge (3), l2 is the offset between the elastically driven hinge (3) and the second hinge (8), l3 is the offset between the second hinge (8) and the elastic hinge (6), and l4 is the offset between the elastic hinge (6) and the first hinge (7); α1 is the angle between the planar sunshade (1) and the base plate (2) around the central axis of the elastically driven hinge (3), α2 is the angle between the base plate (2) and the second support rod (5) around the central axis of the second hinge (8), α3 is the angle between the second support rod (5) and the first support rod (4) around the central axis of the elastic hinge (6), and α4 is the angle between the first support rod (4) and the planar sunshade (1) around the central axis of the first hinge (7).

5. A deployable sunshade based on a spatial four-bar linkage according to any one of claims 1 to 4, characterized in that: The elastic drive hinge (3) is a vortex spring locking hinge; The elastic hinge (6) is a torsion spring pin hinge; The first hinge (7) and the second hinge (8) are both pin hinges.

6. The deployable sunshade based on a spatial four-bar linkage according to claim 5, characterized in that: The elastic drive hinge (3) is a sliding groove type scroll spring locking hinge, comprising a first fixed seat (31), a second fixed seat (32), a male hinge (33), a female hinge (34), a scroll spring (35), a clamping rod (36), a locking pin (37) and a clamping torsion spring (38); The first fixing seat (31) is installed on the upper surface of the base, and the second fixing seat (32) is installed on the outer side wall of the fixed side plate (12); The female hinge (34) is arranged on the first fixed seat (31) and connected to the fixed end of the spiral spring (35); the male hinge (33) is arranged on the second fixed seat (32) and connected to the movable end of the spiral spring (35), so as to enable the male hinge (33) to rotate along the motion track of the movable end of the spiral spring (35); The female hinge (34) is provided with a fixed shaft, and the compression torsion spring (38) is provided on the fixed shaft; One end of the clamping rod (36) is rotatably connected to the fixed shaft, and the other end is fixedly connected to the locking pin (37), and the locking pin (37) is arranged corresponding to the male hinge (33); A sliding groove is provided on the male hinge (33) at a position corresponding to the locking pin (37), and a protrusion is provided on the male hinge (33) at a position below the sliding groove. The working end of the compression torsion spring (38) is pressed against the locking pin (37) so that the locking pin (37) cooperates with the sliding groove or the protrusion when the male hinge (33) moves to different positions.

7. The deployable sunshade based on a spatial four-bar linkage according to claim 1, characterized in that: The locking device (10) comprises a base and a locking rod arranged on the base; A pyrotechnic detonating device is arranged in the base; The pressing seat (9) is provided with a locking hole matched with the locking rod.

8. The deployable sunshade based on a spatial four-bar linkage according to claim 1, characterized in that: The unfolding angle of the elastic driving hinge (3) is 90 degrees.

9. The deployable sunshade based on a spatial four-bar linkage according to claim 8, characterized in that: The included angle between the planar substrate (11) and the upper surface of the light shielding strip (13) is an obtuse angle, and each included angle decreases from top to bottom; The width of the fixed side plate (12) increases from top to bottom; The inner side walls of the two fixed side plates (12) are respectively in contact with two ends of the plurality of light shielding strips (13).

10. The deployable sunshade based on a spatial four-bar linkage according to claim 9, characterized in that: The connection position between the first support rod (4) and the fixed side plate (12) is higher than the connection position between the elastic drive hinge (3) and the fixed side plate (12).

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