A deployable sunshade based on a spatial four-bar linkage

Abstract

The present invention provides a deployable sunshade based on a spatial four-bar linkage, which is used to solve the limitations of existing deployable sunshades with low precision and low rigidity after deployment, as well as the technical problems that existing rigid sunshades can only be applied to space optical systems of smaller sizes. 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, and cooperates with a clamping seat and a locking device to enable the rocket to fold and retract the planar sunshade during launch to achieve a smaller spatial volume; when the rocket reaches the expected position on orbit, 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 retracted state, so that it also has high precision and structural rigidity in the working state.

Description

Technical Field

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

[0002] As the demand for space situational awareness increases, 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. Currently, most large-scale sunshades used in space orbit are one-piece structures and do not have a deployable function. However, due to the limitation of rocket space, the large envelope volume of large-scale sunshades has obvious drawbacks during rocket launch. Therefore, applying the concept of deployable sunshades to large-scale sunshades is a new approach to solve this problem.

[0003] In recent years, numerous researchers have proposed deployable sunshades, primarily combining rigid frames, elastic materials, and inflatable composite materials with flexible composite materials. However, these deployable sunshades suffer from low precision and rigidity after deployment. Space optical cameras require rigid sunshades with high rigidity. Existing solutions include screw-driven cylindrical deployment, but these are primarily used in smaller space optical systems. Summary of the Invention

[0004] The purpose of the present invention is to solve the limitations of existing deployable sunshades that have low precision and low rigidity after deployment, and the technical problems that existing rigid sunshades 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 by:

[0007] It includes a flat sunshade, a bottom plate, two elastically driven hinges and two sets of spatial four-bar linkages;

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

[0009] The outer sides of the two fixed side panels are connected to the upper surfaces of both sides of the bottom panel via elastically driven 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 includes 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 one side fixed side plate by a 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 a 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, 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 linkage mechanisms;

[0012] A pressing seat is respectively provided on the outer side walls of the two fixed side plates, and two locking devices are provided at corresponding positions on the bottom plate, which are used to lock the plane light shield through the pressing seat and the corresponding locking device when the plane light shield is in the folded state.

[0013] Furthermore, the constraint conditions for the motion of the spatially overconstrained Bennett mechanism in space are:

[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 light shield 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 light shield 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 constraints of the spherical 4R linkage mechanism's motion in space are:

[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 drive 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 drive 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 light shield and the base plate around the central axis of the elastic drive 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 light shield around the central axis of the first hinge.

[0024] Furthermore, the constraints of the planar four-bar linkage movement in space are:

[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 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 light shield 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 light shield around the central axis of the first hinge.

[0029] Furthermore, the elastically driven 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] Furthermore, 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 pressing rod, a locking pin and a pressing 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 scroll spring, and the male hinge is arranged on the second fixed seat and connected to the movable end of the scroll spring, so as to make the male hinge rotate along the motion track of the movable end of the scroll 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] Furthermore, the locking device includes a base and a locking rod provided on the base;

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

[0040] The pressing seat is provided with a locking hole adapted to the locking rod. After the remote control pyrotechnic detonator 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 respectively abut against the two ends of 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] The beneficial effects of the present invention compared to the prior art are as follows:

[0045] 1. The present invention provides a deployable sun shield based on a spatial four-bar linkage, which uses a spatial over-constrained Bennett mechanism, a spherical 4R linkage mechanism, or a planar four-bar linkage mechanism as the deployment drive mechanism of the planar sun shield. In conjunction with a clamping seat and a locking device, the rocket can fold and retract the planar sun shield 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 sun shield from a fully retracted state, so that it has higher precision and structural rigidity in the working state, providing new ideas for the on-orbit application of large-size sun shields and filling the gap in large-size and high-rigidity sun shields.

[0046] 2. The present invention provides a deployable light shield based on a spatial four-bar linkage. In the fully retracted state, a space pyrotechnic locking device and a clamping seat are used to securely connect the flat light shield to the base plate, 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 This is a structural schematic diagram of a first embodiment of a deployable sunshade based on a spatial four-bar linkage mechanism according to the present invention;

[0048] Figure 2 Schematic diagram of various parameters of the spatial overconstrained Bennett mechanism in Example 1 of the present invention when it satisfies the spatial motion constraint conditions;

[0049] Figure 3 Schematic diagram of the structure of the elastic drive 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 This is a structural schematic diagram of a second embodiment of a deployable light shield based on a spatial four-bar linkage mechanism according to the present invention;

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

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

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

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

[0058] Figure 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 satisfies the motion constraint conditions in space;

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

[0060] Figure 14 Schematic diagram of the unfolding process of the plane 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 base plate; 12. Fixed side plate; 13. Light-blocking strip; 2. Bottom plate; 3. Elastic drive hinge; 31. First fixing seat; 32. Second fixing 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] Example 1

[0065] like Figure 1 As shown, a deployable sunshade based on a spatial four-bar linkage mechanism includes 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 light shield 1 includes a planar substrate 11, fixed side panels 12 vertically connected to both sides of the planar substrate 11, and multiple light-blocking strips 13 arranged horizontally on the planar substrate 11. The ends of the multiple light-blocking strips 13 respectively abut the inner side walls of the two planar substrates 11. The angles between the planar substrate 11 and the upper surfaces of the light-blocking strips 13 are obtuse, and each angle decreases from top to bottom. Correspondingly, 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-blocking strip 13 is greater than the angle between the planar substrate 11 and the upper surface of the upper light-blocking strip 13, which can better suppress stray light.

[0067] The outer walls of the two fixed side panels 12, near the bottom, are connected to the upper surfaces of the base plate 2 via elastically driven hinges 3. The elastically driven hinges 3 have a 90-degree deployment angle, allowing the planar sunshade 1 to fold 90 degrees. An optical aperture is axially defined in the base plate 2, serving as a light aperture for the optical camera. Multiple light-blocking strips 13 are located on the side of the planar substrate 11 facing the base plate 2 to block stray light. This arrangement ensures that the light-blocking strips 13 are located within the planar sunshade 1 when it is retracted, effectively preventing interference with the light-blocking strips 13.

[0068] The spatial four-bar linkage 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 panel 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 panel 2 on the same side by the second hinge 8; the two sets of spatial four-bar linkages have the same structure and are symmetrically arranged on both sides of the planar sunshade 1, that is, the other end of the other first support rod 4 is hinged to the outer wall of the fixed side panel 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 panel 2 on the corresponding side by the second hinge 8. In this embodiment, the elastic hinge 6 adopts a torsion spring pin hinge, and the first hinge 7 and the second hinge 8 both adopt traditional pin hinges. No torsion spring is added to the first hinge 7 and the second hinge 8, so that redundant drive 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, when in the fully folded state, the first support rod 4 is not parallel to the base plate 2 to avoid the expansion 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 plates 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 deployment drive mechanism of the planar light shield 1. In conjunction with the clamping seat and the locking device, the rocket can fold and retract the planar light shield 1 during launch 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 drive hinge 3 to enable the planar light shield 1 to be deployed from a fully retracted state and locked, providing new ideas for the on-orbit application of large-size light shields.

[0070] like Figure 2 As shown, the four revolute pairs in the spatial overconstrained Bennett mechanism are the elastically driven 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. Define l1 as the offset between the first hinge 7 and the elastically driven hinge 3, l2 as the offset between the elastically driven 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 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, 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. The angle between the first support rod 4 and the planar light shield 1 around the central axis of the first hinge 7 is α4; β1 is the angle between the central axis of the elastically driven hinge 3 and the central axis of the first hinge 7 around their common normal; β2 is the angle between the central axis of the second hinge 8 and the central axis of the elastically driven hinge 3 around their common normal; β3 is the angle between the central axis of the elastic hinge 6 and the central axis of the second hinge 8 around their common normal; and β4 is the angle between the central axis of the first hinge 7 and the central axis of the elastic hinge 6 around their common normal. To achieve the desired angle when the light shield is fully retracted and unfolded, the above parameters must 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 spatially overconstrained Bennett mechanism in space.

[0076] A clamping seat 9 is provided on the outer side walls of the two fixed side panels 12, and two locking devices 10 are provided at corresponding positions on the bottom plate 2, which are used to lock the flat 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 the memory alloy unlocking device commonly used in aerospace. Specifically, the locking device 10 includes a base and a locking rod provided 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 existing types of elastic drive hinges can 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 wall of the fixed side plate 12; the female hinge 34 is arranged on the first fixed seat 31 and is connected to the fixed end of the vortex spring 35; the male hinge 33 is arranged on the second fixed seat 32 and is 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 mounted on the female hinge 34, and a compression torsion spring 38 is mounted 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 a locking pin 37, which is provided corresponding to the male hinge 33. When locked, the male hinge 33 has a slot corresponding to the locking pin 37. A protrusion is provided below the slot on the male hinge 33. The working end of the compression torsion spring 38 presses against the locking pin 37. When the male hinge 33 is in the initial state, the compression torsion spring 38 causes the locking pin 37 to slide into the slot for mechanical limit locking. When the male hinge 33 moves out of the initial state following the scroll spring 35, the compression torsion spring 38 causes the locking pin 37 to press against the protrusion on the male hinge 33.

[0078] The locking process of the vortex spring locking hinge is as follows Figure 4As shown, when the flat light shield 1 is in the retracted state, the scroll spring 35 continuously provides driving torque to the scroll spring locking hinge in the expansion direction. However, due to the action of the locking device 10, the scroll spring locking hinge is in a non-expanded state. When the flat light shield 1 reaches the intended working position, the locking device 10 is unlocked, and the flat light shield 1 is driven to expand under the combined action of the scroll spring 35 torque and the compression torsion spring 38 torque. At the same time, the locking pin 37 is also constantly pressed against the male hinge 33 by the compression torsion spring 38. When the flat light shield 1 is expanded to the intended 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 locked.

[0079] like Figure 5 、 Figure 6 The figure shows a schematic diagram of the unfolding process of the planar light shield 1 using two symmetrically arranged spatial over-constrained Bennett mechanisms. When the planar light shield 1 is in a fully retracted state, that is, the planar light shield 1 is fixedly connected to the base plate 2 by the clamping seat 9 and the locking device 10, and the first support rod 4 and the second support rod 5 are retracted. When the planar light shield 1 reaches the predetermined working position, the locking device 10 is unlocked to eliminate the fixed constraint. At this time, the spiral 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 spatial over-constrained Bennett mechanisms, driving the two spatial over-constrained Bennett mechanisms to unfold according to their own motion trajectories. After unfolding to the predetermined working position, the first support rod 4 and the second support rod 5 are located at the collinear dead point position. 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, realizing the locking of the elastic drive hinge 3. At this time, the planar light shield 1 is in a fully unfolded and locked structural state.

[0080] Example 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 expansion drive mechanism of the flat light shield 1.

[0082] like Figure 8As shown, the four revolute pairs in the spherical 4R linkage 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 planar light shield 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 planar light shield 1 around the center axis of the first hinge 7. In order to achieve the fully retracted and compressed state of the light shield 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 on the motion of the spherical 4R linkage in space.

[0087] like Figure 9 、 Figure 10 FIG. 1 is a schematic diagram showing the process of unfolding the planar sunshade 1 by using two symmetrically arranged spherical 4R link mechanisms.

[0088] Example 3

[0089] The difference between this embodiment and the first embodiment is that Figure 11 As shown, in this embodiment, two sets of spatial four-bar linkages 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 planar four-bar linkages, and the planar four-bar linkages are used as the expansion drive mechanism of the planar light shield 1.

[0090] like Figure 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 light shield 1 and the base plate 2 around the central axis of the elastic drive 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 light shield 1 around the central axis of the first hinge 7. In order to achieve the fully retracted and compressed state of the light shield 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 Figure 13 、 Figure 14 , which 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 this field, the specific technical solutions recorded in the above embodiments can be modified, or some of the technical features therein can be replaced by equivalents. These modifications or replacements do not cause the essence of the corresponding technical solution to 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 by: It comprises a plane light shield (1), a base plate (2), two elastic drive hinges (3) and two sets of spatial four-bar linkage mechanisms; The planar light shield (1) comprises a planar substrate (11), fixed side plates (12) vertically connected to both sides of the planar substrate (11), and a plurality of light-blocking strips (13) arranged transversely on the planar substrate (11); Positions near the bottom of the outer side walls of the two fixed side panels (12) are 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 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 sets of spatial four-bar linkage mechanisms have the same structure and are symmetrically arranged on both sides of the plane light shield (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 pressing seat (9) is provided on the outer side walls of the two fixed side panels (12), and two locking devices (10) are provided at corresponding positions on the bottom panel (2) for locking the plane light shield (1) in a folded state through the pressing seat (9) and the corresponding locking devices (10).

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 spatially 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 light shield (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), 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 angle between the center axis of the chain (6) and the center axis of the first hinge (7) is shown in FIG1 ; α4 is the angle between the first support rod (4) and the plane light shield (1) around the center axis of the first hinge (7); β1 is the angle between the center axis of the elastically driven hinge (3) and the center axis of the first hinge (7) around the common normal of the two; β2 is the angle between the center axis of the second hinge (8) and the center axis of the elastically driven hinge (3) around the common normal of the two; β3 is the angle between the center axis of the elastic hinge (6) and the center axis of the second hinge (8) around the common normal of the two; and β4 is the angle between the center axis of the first hinge (7) and the center 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 constraints of the spherical 4R linkage mechanism's motion 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 elastically driven 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 elastically driven 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; and 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 light shield (1) and the base plate (2) around the center axis of the elastically driven 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 light shield (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 constraints of the planar four-bar linkage motion 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 light shield (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 light shield (1) around the central axis of the first hinge (7).

5. The 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 vortex spring locking hinge, comprising a first fixed seat (31), a second fixed seat (32), a male hinge (33), a female hinge (34), a vortex spring (35), a pressing rod (36), a locking pin (37) and a pressing torsion spring (38); The first fixing seat (31) is mounted on the upper surface of the base, and the second fixing seat (32) is mounted 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); 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 pressing 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 provided 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) presses 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 provided in the base; The pressing seat (9) is provided with a locking hole adapted to 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 drive 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-blocking 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) respectively abut against two ends of the plurality of light-blocking 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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