阅读说明：本技术 单自由度四面体可展胞元机构 (Single-degree-of-freedom tetrahedral deployable cell element mechanism ) 是由 杨洋 陈子路 广晨汉 于 2019-10-25 设计创作，主要内容包括：本发明涉及可展胞元技术领域,具体公开了一种单自由度四面体可展胞元机构,包括第一连杆、第一转动副、第二连杆、第二转动副、第三连杆、第四转动副、第四连杆、第三转动副、第九转动副、第八连杆、第十转动副、第九连杆、第十一转动副、第七转动副、第七连杆、第六连杆、第八转动副、第六转动副、第五连杆和第五转动副。本发明包括九个连杆和十一个转动副,这种结构的单自由度四面体可展胞元机构结构简单,运动副更少,完全采用转动副,机构精度更高。(The invention relates to the technical field of deployable cell elements, and particularly discloses a single-degree-of-freedom tetrahedral deployable cell element mechanism which comprises a first connecting rod, a first rotating pair, a second connecting rod, a second rotating pair, a third connecting rod, a fourth rotating pair, a fourth connecting rod, a third rotating pair, a ninth rotating pair, an eighth connecting rod, a tenth rotating pair, a ninth connecting rod, an eleventh rotating pair, a seventh connecting rod, a sixth connecting rod, an eighth rotating pair, a sixth rotating pair, a fifth connecting rod and a fifth rotating pair. The mechanism comprises nine connecting rods and eleven rotating pairs, and the single-degree-of-freedom tetrahedral deployable cell mechanism with the structure has a simple structure, fewer moving pairs and higher mechanism precision due to the complete adoption of the rotating pairs.)

1. A single-degree-of-freedom tetrahedral deployable cell mechanism is characterized by comprising a first connecting rod (1), a first revolute pair (2), a second connecting rod (3), a second revolute pair (4), a third connecting rod (5), a fourth revolute pair (6), a fourth connecting rod (7), a third revolute pair (8), a ninth revolute pair (9), an eighth connecting rod (10), a tenth revolute pair (11), a ninth connecting rod (12), an eleventh revolute pair (13), a seventh revolute pair (14), a seventh connecting rod (15), a sixth connecting rod (16), an eighth revolute pair (17), a sixth revolute pair (18), a fifth connecting rod (19) and a fifth revolute pair (20);

one end of the first connecting rod (1) is connected with one end of the second connecting rod (3) through the first revolute pair (2), the other end of the second connecting rod (3) is connected with one end of the third connecting rod (5) through the second revolute pair (4), the other end of the third connecting rod (5) is connected with one end of the fourth connecting rod (7) through the third revolute pair (8), and the other end of the fourth connecting rod (7) is connected with the other end of the first connecting rod (1) through the fourth revolute pair (6); when the single-degree-of-freedom tetrahedral deployable cell mechanism is completely deployed, the axes of the first rotating pair (2), the second rotating pair (4), the third rotating pair (8) and the fourth rotating pair (6) are parallel, the axes of the first rotating pair (2), the second rotating pair (4) and the third rotating pair (8) are coplanar, the first connecting rod (1) is perpendicular to the fourth connecting rod (7), the second connecting rod (3) is collinear with the third connecting rod (5), when the single-degree-of-freedom tetrahedral deployable cell mechanism is completely folded, the second connecting rod (3) can be embedded into the groove of the third connecting rod (5), the third connecting rod (5) can be embedded into the groove of the fourth connecting rod (7), and the axes of the first rotating pair (2), the second rotating pair (4), the third rotating pair (8) and the fourth rotating pair (6) are parallel and coplanar, the first connecting rod (1), the second connecting rod (3), the third connecting rod (5) and the fourth connecting rod (7) are parallel;

the structures and the connection relations of the fifth revolute pair (20), the fifth connecting rod (19), the sixth revolute pair (18), the sixth connecting rod (16), the eighth revolute pair (17), the seventh connecting rod (15) and the seventh revolute pair (14) are the same as those of the first revolute pair (2), the second connecting rod (3), the second revolute pair (4), the third connecting rod (5), the fourth revolute pair (6), the fourth connecting rod (7) and the third revolute pair (8), the fifth connecting rod (19) is connected with the first connecting rod (1) through the fifth revolute pair (20), the first connecting rod (15) is connected with the first connecting rod (1) through the eighth revolute pair (17), and the axis of the fifth revolute pair (20) is perpendicular to the axis of the first revolute pair (2);

the fourth link (7) is connected with the eighth link (10) through the ninth revolute pair (9), the eighth link (10) is connected with the ninth link (12) through the tenth revolute pair (11), the ninth link (12) is connected with the seventh link (15) through the eleventh revolute pair (13), the axis of the ninth revolute pair (9) is perpendicular to the axis of the third revolute pair (8), and the axis of the eleventh revolute pair (13) is perpendicular to the axis of the seventh revolute pair (14); the included angle between the axis of the tenth revolute pair (11) and the first connecting rod (1) is 45 degrees, when the single-degree-of-freedom tetrahedral deployable cell element mechanism is completely unfolded, the eighth connecting rod (10) and the ninth connecting rod (12) are collinear, and when the single-degree-of-freedom tetrahedral deployable cell element mechanism is completely folded, the eighth connecting rod (10) and the ninth connecting rod (12) are attached.

2. The mechanism according to claim 1, wherein the first revolute pair (2) has an axis a spaced from the fourth revolute pair (6) and the third revolute pair (8) has an axis b spaced from the fourth revolute pair (6), a ≠ b.

3. The mechanism of claim 2, wherein a > b, the distance between the axis of the first revolute pair (2) and the axis of the second revolute pair (4) is c,

the distance between the axis of the second revolute pair (4) and the axis of the third revolute pair (8) is d,

4. the mechanism of claim 1, wherein the first link (1) has a square cross-section, the second link (3) and the fifth link (19) have a rectangular cross-section, the third link (5), the fourth link (7), the sixth link (16) and the seventh link (15) have a concave cross-section, and the eighth link (10) and the ninth link (12) have an isosceles right triangle cross-section.

Technical Field

The invention relates to the technical field of deployable cell elements, in particular to a single-degree-of-freedom tetrahedral deployable cell element mechanism.

Background

With the continuous development of space technology, the application of large space functional loads such as space telescopes, space antennas, space stations and the like is gradually wide. In the space installation and use of the equipment, a large space load bearing structure meeting certain rigidity and precision is required to be used as a base of the equipment, so that the equipment plays roles of fixing and bearing. Because the envelope volume of the load bearing structure during working is large, the carrier rocket cannot be directly launched to the air. The adoption of a large-scale deployable mechanism has the problems of complex mechanism, high assembly precision requirement, easy blocking in the deployment process and the like.

Thus, solutions have been created to carry the components of the load bearing structure to a designated track, and then build the truss-like load platform directly in space. The space truss can be split into identical polyhedral cells and each cell can be converted into a mechanism. And folding the cell element mechanism during transmission, and unfolding and assembling the folded cell element mechanism in sequence after the cell element mechanism is conveyed to a specified track to complete the construction of the space truss. The shape of the spatial deployable cell element mechanism is various, such as a triangular prism, a hexagonal prism, a rectangular pyramid, etc., wherein the tetrahedral deployable cell element mechanism has the advantages of flexible assembly, less redundant rods, light weight, etc. The existing tetrahedron expandable cell element mechanism has few types, more rod members, complex structure, and the problem that the ball pair reduces the motion precision.

Among the existing tetrahedral expandable units, for example, the one-degree-of-freedom tetrahedral expandable unit with patent number 201510672988.0, is composed of a top face plate, three equal-length rocking bars, six connecting rods, nine revolute pairs and three ball pairs. The flower-ejecting plate is respectively connected with the three swing rods through three revolute pairs which are symmetrically distributed at 120 degrees, the tail ends of the three swing rods are connected with each other in a pairwise mode, and the connection mode is the same as follows: the tail end of one rocking rod is connected with one end of one connecting rod through a revolute pair, the other end of the connecting rod is connected with one end of the other connecting rod through a ball pair, and the connecting rod is connected with the tail end of the other rocking rod through a revolute pair. The mechanism uses a total of ten parts, twelve kinematic pairs and three of them. The rod pieces are more, so that the mechanism is complex in structure and large in weight, and in addition, the clearance of the ball pair is large, so that the overall movement precision of the mechanism is low.

Disclosure of Invention

The invention aims to provide a tetrahedral deployable cell element mechanism with single degree of freedom, which solves the problems of more motion pairs, more ball pairs, more rod pieces, lower motion precision and the like of a tetrahedral deployable unit in the prior art.

In order to solve the above technical problem, the present invention provides a tetrahedral deployable cell element mechanism with single degree of freedom, which comprises a first connecting rod, a first revolute pair, a second connecting rod, a second revolute pair, a third connecting rod, a fourth revolute pair, a fourth connecting rod, a third revolute pair, a ninth revolute pair, an eighth connecting rod, a tenth revolute pair, a ninth connecting rod, an eleventh revolute pair, a seventh connecting rod, a sixth connecting rod, an eighth revolute pair, a sixth revolute pair, a fifth connecting rod and a fifth revolute pair;

one end of the first connecting rod is connected with one end of the second connecting rod through the first revolute pair, the other end of the second connecting rod is connected with one end of the third connecting rod through the second revolute pair, the other end of the third connecting rod is connected with one end of the fourth connecting rod through the third revolute pair, and the other end of the fourth connecting rod is connected with the other end of the first connecting rod through the fourth revolute pair; when the single-degree-of-freedom tetrahedral expandable cell mechanism is completely expanded, the axes of the first rotating pair, the second rotating pair, the third rotating pair and the fourth rotating pair are parallel, the axes of the first rotating pair, the second rotating pair and the third rotating pair are coplanar, the first connecting rod is perpendicular to the fourth connecting rod, the second connecting rod is collinear with the third connecting rod, when the single-degree-of-freedom tetrahedral expandable cell mechanism is completely folded, the second connecting rod can be embedded into a groove of the third connecting rod, the third connecting rod can be embedded into a groove of the fourth connecting rod, the axes of the first rotating pair, the second rotating pair, the third rotating pair and the fourth rotating pair are parallel and coplanar, and the first connecting rod, the second connecting rod, the third connecting rod and the fourth connecting rod are parallel;

the structure and the connection relationship of the fifth revolute pair, the fifth connecting rod, the sixth revolute pair, the sixth connecting rod, the eighth revolute pair, the seventh connecting rod and the seventh revolute pair are the same as those of the first revolute pair, the second connecting rod, the second revolute pair, the third connecting rod, the fourth revolute pair, the fourth connecting rod and the third revolute pair, the fifth connecting rod is connected with the first connecting rod through the fifth revolute pair, the first connecting rod is connected with the first connecting rod through the eighth revolute pair, and the axis of the fifth revolute pair is perpendicular to the axis of the first revolute pair;

the fourth connecting rod is connected with the eighth connecting rod through the ninth revolute pair, the eighth connecting rod is connected with the ninth connecting rod through the tenth revolute pair, the ninth connecting rod is connected with the seventh connecting rod through the eleventh revolute pair, the axis of the ninth revolute pair is perpendicular to the axis of the third revolute pair, and the axis of the eleventh revolute pair is perpendicular to the axis of the seventh revolute pair; the included angle between the axis of the tenth revolute pair and the first connecting rod is, when the single-degree-of-freedom tetrahedral expandable cellular mechanism is completely expanded, the eighth connecting rod and the ninth connecting rod are collinear, and when the single-degree-of-freedom tetrahedral expandable cellular mechanism is completely folded, the eighth connecting rod and the ninth connecting rod are attached.

Preferably, a distance between the axis of the first revolute pair and the axis of the fourth revolute pair is a, and a distance between the axis of the third revolute pair and the axis of the fourth revolute pair is b, where a ≠ b.

Preferably, a > b, the distance between the axis of the first rotating pair and the axis of the second rotating pair is c,

the distance between the axis of the second revolute pair and the axis of the third revolute pair is d,

preferably, the cross section of the first connecting rod is square, the cross sections of the second connecting rod and the fifth connecting rod are rectangular, the cross sections of the third connecting rod, the fourth connecting rod, the sixth connecting rod and the seventh connecting rod are concave, and the cross sections of the eighth connecting rod and the ninth connecting rod are isosceles right triangles.

In the single-degree-of-freedom tetrahedral deployable cell element mechanism, a first connecting rod, a second connecting rod, a third connecting rod and a fourth connecting rod form a right-angled triangle mechanism, the first connecting rod, a fifth connecting rod, a sixth connecting rod and a seventh connecting rod form another right-angled triangle mechanism, the two right-angled triangle mechanisms are mutually vertical, the fourth connecting rod is connected with an eighth connecting rod through a ninth revolute pair, the eighth connecting rod is connected with a ninth connecting rod through a tenth revolute pair, the ninth connecting rod is connected with a seventh connecting rod through an eleventh revolute pair, and an included angle between the fourth connecting rod and the eighth connecting rod and an included angle between the seventh connecting rod and the ninth connecting rod are 45 degrees.

Drawings

Fig. 1 is a schematic structural diagram of a fully deployed single-degree-of-freedom tetrahedral deployable cell mechanism according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a half-unfolded structure of a one-degree-of-freedom tetrahedral expandable cell mechanism according to an embodiment of the present invention;

fig. 3 is a schematic structural diagram of the fully folded one-degree-of-freedom tetrahedral expandable cell mechanism according to the embodiment of the present invention.

In the figure, 1: a first link; 2: a first rotating pair; 3: a second link; 4: a second revolute pair; 5: a third link; 6: a fourth revolute pair; 7: a fourth link; 8: a third revolute pair; 9: a ninth revolute pair; 10: an eighth link; 11: a tenth revolute pair; 12: a ninth link; 13: an eleventh revolute pair; 14: a seventh revolute pair; 15: a seventh connecting rod; 16: a sixth link; 17: an eighth revolute pair; 18: a sixth revolute pair; 19: a fifth link; 20: and a fifth revolute pair.

Detailed Description

The embodiments of the present invention will be described in further detail with reference to the drawings and examples. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.

In the description of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. Unless expressly stated or limited otherwise, the terms "mounted," "connected," and "connected" are intended to be inclusive and mean, for example, that they may be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

As shown in fig. 1-3, the one-degree-of-freedom tetrahedral deployable cell mechanism of the present embodiment comprises: the first link 1, the first revolute pair 2, the second link 3, the second revolute pair 4, the third link 5, the fourth revolute pair 6, the fourth link 7, the third revolute pair 8, the ninth revolute pair 9, the eighth link 10, the tenth revolute pair 11, the ninth link 12, the eleventh revolute pair 13, the seventh revolute pair 14, the seventh link 15, the sixth link 16, the eighth revolute pair 17, the sixth revolute pair 18, the fifth link 19 and the fifth revolute pair 20.

One end of the first connecting rod 1 is connected with one end of the second connecting rod 3 through the first revolute pair 2, the other end of the second connecting rod 3 is connected with one end of the third connecting rod 5 through the second revolute pair 4, the other end of the third connecting rod 5 is connected with one end of the fourth connecting rod 7 through the third revolute pair 8, and the other end of the fourth connecting rod 7 is connected with the other end of the first connecting rod 1 through the fourth revolute pair 6; when the single-degree-of-freedom tetrahedral expandable cell mechanism is completely unfolded (as shown in fig. 1), the axes of the first rotating pair 2, the second rotating pair 4, the third rotating pair 8 and the fourth rotating pair 6 are parallel, the axes of the first rotating pair 2, the second rotating pair 4 and the third rotating pair 8 are coplanar, the first connecting rod 1 is perpendicular to the fourth connecting rod 7, the second connecting rod 3 is collinear with the third connecting rod 5, when the single-degree-of-freedom tetrahedral expandable cell mechanism is completely folded (as shown in fig. 3), the second connecting rod 3 can be embedded into the groove of the third connecting rod 5, the third connecting rod 5 can be embedded into the groove of the fourth connecting rod 7, the axes of the first rotating pair 2, the second rotating pair 4, the third rotating pair 8 and the fourth rotating pair 6 are parallel and coplanar, and the first connecting rod 1, the second connecting rod 3, the third connecting rod 5 and the fourth connecting rod 7 are parallel.

The structures and the connection relations of the fifth revolute pair 20, the fifth connecting rod 19, the sixth revolute pair 18, the sixth connecting rod 16, the eighth revolute pair 17, the seventh connecting rod 15 and the seventh revolute pair 14 are the same as those of the first revolute pair 2, the second connecting rod 3, the second revolute pair 4, the third connecting rod 5, the fourth revolute pair 6, the fourth connecting rod 7 and the third revolute pair 8, the fifth connecting rod 19 is connected with the first connecting rod 1 through the fifth revolute pair 20, the first connecting rod 15 is connected with the first connecting rod 1 through the eighth revolute pair 17, and the axis of the fifth revolute pair 20 is perpendicular to the axis of the first revolute pair 2. As shown in fig. 1, the first revolute pair 2 and the fifth revolute pair 20 intersect at a point a, the fourth revolute pair 6 and the eighth revolute pair 17 intersect at a point B, AB is perpendicular to the axes of the first revolute pair 2 and the fourth revolute pair 6, the axes of the fifth revolute pair 20 and the eighth revolute pair 17 are perpendicular to the straight line AB and the axes of the first revolute pair 2 and the fourth revolute pair 6, and the first revolute pair 2, the fourth revolute pair 6, the fifth revolute pair 20 and the eighth revolute pair 17 are symmetrical about a plane C. The fifth link 19, the sixth link 16, the seventh link 14 and the ninth link 12 are respectively arranged symmetrically with the second link 3, the third link 5, the fourth link 7 and the eighth link 10 about the plane C.

The fourth connecting rod 7 is connected with an eighth connecting rod 10 through a ninth revolute pair 9, the eighth connecting rod 10 is connected with a ninth connecting rod 12 through a tenth revolute pair 11, the ninth connecting rod 12 is connected with a seventh connecting rod 15 through an eleventh revolute pair 13, the axis of the ninth revolute pair 9 is perpendicular to the axis of the third revolute pair 8, and the axis of the eleventh revolute pair 13 is perpendicular to the axis of the seventh revolute pair 14; the included angle between the axis of the tenth revolute pair 11 and the first connecting rod 1 is 45 degrees, when the single-degree-of-freedom tetrahedral deployable cell element mechanism is completely deployed (as shown in fig. 1), the eighth connecting rod 10 and the ninth connecting rod 12 are collinear, the ninth revolute pair 9, the third revolute pair 8 and the fourth revolute pair 6 are perpendicular to the axis and intersect with a point D, the eleventh revolute pair 13, the fourth revolute pair 6 and the seventh revolute pair 14 are perpendicular to a point E, the tenth revolute pair 11 is on a plane C, the included angle between the tenth revolute pair and a straight line AB is 45 degrees and passes through the midpoint of a CD, when the single-degree-of-freedom tetrahedral deployable cell element mechanism is completely folded (as shown in fig. 3), the eighth connecting rod 10 and the ninth connecting rod 12 are attached, all the connecting rods are parallel.

If the distance between the axis of the first revolute pair 2 and the axis of the fourth revolute pair 6 is a and the distance between the axis of the third revolute pair 8 and the axis of the fourth revolute pair 6 is b, a ≠ b.

If a is larger than b, the distance between the axis of the first rotating pair 2 and the axis of the second rotating pair 4 is c, then

The distance between the axis of the second revolute pair 4 and the axis of the third revolute pair 8 is d, then

The cross section of the first connecting rod 1 is square, the cross sections of the second connecting rod 3 and the fifth connecting rod 19 are rectangular, the cross sections of the third connecting rod 5, the fourth connecting rod 7, the sixth connecting rod 16 and the seventh connecting rod 15 are concave, and the cross sections of the eighth connecting rod 10 and the ninth connecting rod 12 are isosceles right triangles.

In the single-degree-of-freedom tetrahedral deployable cell element mechanism, a first connecting rod, a second connecting rod, a third connecting rod and a fourth connecting rod form a right-angled triangle mechanism, the first connecting rod, a fifth connecting rod, a sixth connecting rod and a seventh connecting rod form another right-angled triangle mechanism, the two right-angled triangle mechanisms are mutually vertical, the fourth connecting rod is connected with an eighth connecting rod through a ninth revolute pair, the eighth connecting rod is connected with a ninth connecting rod through a tenth revolute pair, the ninth connecting rod is connected with a seventh connecting rod through an eleventh revolute pair, and an included angle between the fourth connecting rod and the eighth connecting rod and an included angle between the seventh connecting rod and the ninth connecting rod are 45 degrees.

The embodiments of the present invention have been presented for purposes of illustration and description, and are not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiment was chosen and described in order to best explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated.