Fluid pressure positive feedback sealing and positioning structure and fluid-driven robot module

Abstract

The invention belongs to the technical field of flexible brakes, and particularly provides a fluid pressure positive feedback sealing and positioning structure and a fluid-driven robot module, and the fluid-driven robot module comprises a flexible side wall and the fluid pressure positive feedback sealing and positioning structure. The fluid pressure positive feedback sealing positioning structure comprises a fixing part, a pressing part and a sealing combination part extending from the flexible side wall to the position between the fixing part and the pressing part, a deformable cavity is defined by the fixing part and the flexible side wall, and the sealing combination part is extruded by the pressing part and the fixing part to generate prestrain. When the fluid pressure in the cavity is increased, the fluid pressure can act on the pressing piece, the deformation quantity of the sealing combination part is increased through the pressing piece, the sealing reliability is improved, and the problem that sealing fails due to the fact that the fluid pressure in the cavity is too large is effectively solved. Therefore, the bearing capacity of the flexible side wall and the bearing capacity of the fixing piece can be brought into full play, so that the fluid-driven flexible actuator has higher power output capacity.

Description

Technical Field

[0001] The present application belongs to the technical field of flexible actuators, and specifically relates to a fluid pressure positive feedback sealing positioning structure and a fluid driven robot module. Background Art

[0002] A flexible actuator is a device that can convert external stimuli such as light, temperature, humidity, pressure, pH value, electricity, magnetism or chemical action into mechanical work. It is an important component of soft robots and wearable devices. It mainly receives external stimuli and uses special structures or materials to produce changes in volume and shape to achieve reversible movements such as movement or shaping, and realize functions such as bending, grasping and moving. Pneumatic flexible actuators achieve movement through gas, and usually include a flexible cavity. By filling and deflating the flexible cavity, it can achieve movements such as extension and bending. The power output capacity of the pneumatic flexible actuator is positively correlated with the fluid pressure inside the flexible cavity. The pneumatic flexible actuator usually includes a flexible side wall and other components that are sealed and connected to the end of the flexible side wall. The flexible side wall and other components enclose a flexible cavity. The internal fluid pressure that the pneumatic flexible actuator can withstand requires the bearing capacity of the flexible side wall itself, the bearing capacity of other components themselves, and the sealing between the two. At present, the self-strength of the flexible side wall and other components is no longer the bottleneck of the power output capacity of the pneumatic flexible actuator. However, the sealing effect of the flexible cavity of the current pneumatic flexible actuator is not ideal. When the fluid pressure inside the cavity is too large, it usually leads to sealing failure. Moreover, the greater the fluid pressure inside the cavity, the more serious the leakage problem, so it is impossible to give full play to the bearing capacity of the flexible side wall and other components themselves to achieve greater power output capacity. In addition, the shape stability of the end of the flexible side wall is a prerequisite for effective control of the flexible actuator. Unexpected deformation under high or low pressure (abnormal local protrusion under high pressure and abnormal local collapse under low pressure, etc.) will cause the drive control to fail and fail to perform the predetermined operation. Summary of the invention

[0003] The purpose of the present application is to provide a fluid pressure positive feedback sealing positioning structure and a fluid-driven robot module, aiming to solve the technical problems in the prior art of unsatisfactory sealing effect of the flexible cavity of the pneumatic flexible actuator and insufficient shape stability of the flexible side wall end.

[0004] On the one hand, to achieve the above-mentioned purpose, the technical solution adopted in the present application is: a fluid pressure positive feedback sealing positioning structure, used in a fluid-driven flexible actuator with a rated working pressure difference upper limit of not less than 50MPa, the fluid-driven flexible actuator includes a cylindrical flexible side wall, the fluid pressure positive feedback sealing positioning structure is characterized in that the fluid pressure positive feedback sealing positioning structure includes a fixing part, a pressing part and a sealing joint extending from the end of the flexible side wall to the fixing part and the pressing part, the fixing part and the flexible side wall are enclosed to form a deformable cavity, the fixing part has a first contact surface facing the cavity, the pressing part is arranged in the cavity, the pressing part has a fluid pressure receiving surface facing away from the fixing part and a second contact surface facing the fixing part, the pressing part and the fixing part are connected, when the fluid-driven flexible actuator is in an initial state, the sealing joint is squeezed by the pressing part and the fixing part to generate pre-strain, the fixing part and the pressing part include a first material with an elastic modulus greater than 50GPa, the sealing joint includes a second material with an elastic modulus of 10 to 1000MPa and a positive Poisson's ratio, and the sealing joint The invention has a third contact surface and a fourth contact surface, the third contact surface is sealingly abutted against the first contact surface, the fourth contact surface is sealingly abutted against the second contact surface, the first contact surface and the second contact surface enclose an annular body limiting space with an axially offset opening to partially accommodate a sealing joint, the annular body limiting space has a fixed width and a variable height, the height direction of the annular body limiting space is consistent with the axial direction of the flexible side wall, the annular body limiting space has a first annular opening and a second annular opening that are staggered, the first annular opening is for the sealing joint to connect the flexible side wall, the second annular opening is arranged between the fixing part and the pressing part along the height direction of the annular body limiting space, the sealing joint can completely fit the shape of the annular body limiting space due to prestrain, thereby cutting off the channel between the cavity and the external environment; when the fluid pressure in the cavity increases, it can act on the fluid pressure bearing surface to make the pressing part move toward the fixing part to reduce the height of the annular body limiting space, increase the deformation of the sealing joint, thereby increasing the pressure between the sealing joint and the first contact surface and the second contact surface, forming a positive feedback relationship between the sealing effect and the fluid pressure.

[0005] Compared with the prior art, the beneficial effects of the fluid pressure positive feedback sealing structure provided by the present application are as follows: When the fluid drives the flexible brake to be in the initial state, due to the influence of assembly, the sealing joint is squeezed by the pressing member and the fixing member to generate a certain pre-strain, and due to this pre-strain, it completely conforms to the shape of the annular body limiting space, so that the third contact surface is in sealing contact with the first contact surface, and the fourth contact surface is in sealing contact with the second contact surface, so as to cut off the channel between the cavity and the external environment and play a sealing role. When the fluid pressure in the cavity increases, the fluid pressure along the axial direction of the flexible side wall is received by the fluid pressure receiving surface of the pressing member and transferred to the sealing joint through the pressing member. The setting of the second annular opening provides space for the pressing member to move towards the fixing member. Under the action of the fluid pressure, the pressing member moves towards the fixing member to reduce the height of the annular body limiting space, increase the deformation amount of the sealing joint, thereby increasing the pressure between the sealing joint and the first contact surface and the second contact surface, achieving the effect of enhancing the sealing effect. And the deformation amount of the sealing joint will increase with the increase of the internal pressure of the cavity, showing a positive feedback relationship. The increase in the deformation amount of the sealing joint can make the first contact surface and the third contact surface fit more tightly, and make the second contact surface and the fourth contact surface fit more tightly, thus realizing the positive feedback between the sealing reliability and the fluid pressure in the cavity, effectively avoiding the problem of sealing failure caused by excessive fluid pressure in the cavity. Moreover, the fixed width of the annular body limiting space can limit the lateral expansion of the sealing joint, which is beneficial to increasing the compression amount of the sealing joint along the height direction of the annular body limiting space, making the sealing joint fit more tightly with the first contact surface and the second contact surface, further enhancing the sealing effect, and thus being beneficial to giving full play to the bearing capacity of the flexible side wall and the fixing member itself so that the fluid-driven flexible actuator has a greater power output capacity. In addition, the elastic modulus of the pressing member and the fixing member is greater than that of the sealing joint, that is, the stiffness of the pressing member and the fixing member is greater than that of the sealing joint. The sealing joint is shaped and limited from two opposite directions by the pressing member and the fixing member with greater stiffness, which can ensure the shape stability of the sealing joint, and thus can effectively control the fluid-driven flexible actuator.

[0006] Further, the sealing joint is integrally formed with the flexible side wall.

[0007] Further, the sealing joint includes an outer coating layer and an inner reinforcing layer disposed in the outer coating layer. The surface of the outer coating layer includes a third contact surface and a fourth contact surface. The outer coating layer includes a second material, and the inner reinforcing layer includes a third material with an elastic modulus greater than 1 GPa.

[0008] Further, the sealing joint is located at the edge of the pressing member and extends along the edge contour line of the pressing member to form a closed-loop structure arranged around the central axis of the cavity. The pressing member has a connecting portion for connecting the fixing member; when the number of connecting portions is greater than two, the distance between the connecting portion and the edge contour line of the pressing member is less than the distance between two connecting portions.

[0009] Further, the annular body limiting space is a circular cylindrical shape. The first contact surface includes a first axial contact surface and a first radial contact surface that are perpendicularly connected; the second contact surface includes a second axial contact surface and a second radial contact surface that are perpendicularly connected; the third contact surface includes a third axial contact surface and a third radial contact surface that are perpendicularly connected. The third axial contact surface is in sealing abutment with the first axial contact surface, and the third radial contact surface is in sealing abutment with the first radial contact surface; the fourth contact surface includes a fourth axial contact surface and a fourth radial contact surface that are perpendicularly connected. The fourth axial contact surface is in sealing abutment with the second axial contact surface, and the fourth radial contact surface is in sealing abutment with the second radial contact surface.

[0010] Further, the second radial contact surface is an equal-width cylindrical surface with a width of L1, and the distance between the first radial contact surface and the second radial contact surface is L2; when the sealing joint is not deformed, the distance between the third axial contact surface and the fourth axial contact surface is D1, and the distance between the third radial contact surface and the fourth radial contact surface is D2, 1.2L1 < D1 < 2L1, 1.05D2 < L2 < 1.2D2; when the fluid-driven flexible actuator is in the initial state, the distance between the third axial contact surface and the fourth axial contact surface is D3, 0.7D2 < D3 < D2.

[0011] Further, the second radial contact surface is a cylindrical surface, an elliptical cylindrical surface, or a racetrack-shaped cylindrical surface. The second axial contact surface is in a circular ring shape, an elliptical ring shape, or a racetrack ring shape. The shape of the fourth radial contact surface is adapted to the shape of the second radial contact surface, and the shape of the fourth axial contact surface is adapted to the shape of the second axial contact surface.

[0012] Further, the fixing member further has a fifth axial contact surface that is perpendicular to the first radial contact surface. The fifth axial contact surface and the first axial contact surface are respectively connected to the opposite sides of the first radial contact surface; The pressing member further has a fifth radial contact surface that is perpendicular to the second axial contact surface. The fifth radial contact surface and the second radial contact surface are respectively connected to the opposite sides of the second axial contact surface; The sealing joint further has a sixth axial contact surface and a sixth radial contact surface. The sixth axial contact surface is perpendicularly connected to the third radial contact surface and is in sealing abutment with the fifth axial contact surface. The sixth radial contact surface is perpendicularly connected to the fourth axial contact surface and is in sealing abutment with the fifth radial contact surface.

[0013] On the other hand, to achieve the above object, the technical solution adopted in this application is as follows: A fluid-driven robot module includes a flexible sidewall and the above-mentioned fluid pressure positive feedback sealing and positioning structure.

[0014] Compared with the prior art, the beneficial effects of the fluid-driven robot module provided in this application are as follows: By applying the above-mentioned fluid pressure positive feedback sealing and positioning structure, when the fluid-driven flexible brake is in the initial state, due to the influence of assembly, the sealing joint is extruded by the pressing member and the fixing member to generate a certain pre-strain, and due to this pre-strain, it completely fits the shape of the annular body limiting space, so that the third contact surface is in sealing contact with the first contact surface, and the fourth contact surface is in sealing contact with the second contact surface, so as to cut off the channel between the cavity and the external environment and play a sealing role. When the fluid pressure in the cavity is increased, the fluid pressure along the axial direction of the flexible sidewall will be received by the fluid pressure receiving surface of the pressing member and transferred to the sealing joint through the pressing member. The setting of the second annular opening provides space for the pressing member to move towards the fixing member. Under the action of the fluid pressure, the pressing member moves towards the fixing member to reduce the height of the annular body limiting space, increase the deformation amount of the sealing joint, and thus increase the pressure between the sealing joint and the first contact surface and the second contact surface, achieving the effect of enhancing the sealing effect. Moreover, the deformation amount of the sealing joint will increase with the increase of the internal pressure of the cavity, showing a positive feedback relationship. The increase in the deformation amount of the sealing joint can make the first contact surface and the third contact surface fit more closely, and the second contact surface and the fourth contact surface fit more closely, thus realizing the positive feedback between the sealing reliability and the fluid pressure in the cavity, effectively avoiding the problem of sealing failure caused by excessive fluid pressure in the cavity. In addition, the fixed width of the annular body limiting space can limit the lateral expansion of the sealing joint, which is beneficial to increasing the compression amount of the sealing joint along the height direction of the annular body limiting space, making the sealing joint fit more closely with the first contact surface and the second contact surface, and further enhancing the sealing effect, so as to be conducive to giving full play to the bearing capacity of the flexible sidewall and the fixing member itself, so that the fluid-driven flexible actuator has a greater power output capacity. In addition, the elastic modulus of the pressing member and the fixing member is greater than that of the sealing joint, that is, the stiffness of the pressing member and the fixing member is greater than that of the sealing joint. The sealing joint is shaped and limited from two opposite directions by the pressing member and the fixing member with greater stiffness, which can ensure the shape stability of the sealing joint, and thus can effectively control the fluid-driven flexible actuator.

[0015] Furthermore, the flexible sidewall includes a strain-uniform stacking structure that can be folded and / or extended along the central axis direction of the cavity. The strain-uniform stacking structure includes at least two strain-uniform stacking layers stacked along the central axis direction of the cavity. The strain-uniform stacking layer is enclosed by a single folding surface. The connection of the folding surfaces of adjacent two strain-uniform stacking layers forms a crease. The surface where the crease is located is a plane and perpendicular to the central axis of the cavity. The included angle between the folding surface adjacent to the sealing joint and the plane passing through any point on the sealing joint and perpendicular to the central axis on the side facing the central axis of the cavity is α, where α < 60° or α > 120°. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0017] Figure 1 It is a cross-sectional view of a partial structure of a fluid-driven robot module provided by an embodiment of the present application; Figure 2 For Figure 1 It is a schematic diagram of a partial structure of the fluid pressure positive feedback sealing and positioning structure of the fluid-driven robot module shown after hiding the sealing joint; Figure 3 For Figure 1 It is a schematic diagram of the structure of the sealing joint of the fluid pressure positive feedback sealing and positioning structure of the fluid-driven robot module shown when no deformation occurs; Figure 4 It is a cross-sectional view of a partial structure of another fluid-driven robot module provided by an embodiment of the present application; Figure 5 For Figure 4 It is a schematic diagram of a partial structure of the fluid pressure positive feedback sealing and positioning structure of the fluid-driven robot module shown after hiding the sealing joint; Figure 6 For Figure 4 It is a schematic diagram of the structure of the sealing joint of the fluid pressure positive feedback sealing and positioning structure of the fluid-driven robot module shown when no deformation occurs.

[0018] Wherein, each reference numeral in the figure: 10. Flexible sidewall; 11. Folding surface; 12. Crease; 20. Fixing member; 21. First contact surface; 211. First axial contact surface; 212. First radial contact surface; 22. Through hole; 23. Fifth axial contact surface; 24. Avoidance groove; 241. Eighth axial contact surface; 25. Fluid passage hole; 30. Pressing member; 31. Fluid pressure receiving surface; 32. Second contact surface; 321. Second axial contact surface; 322. Second radial contact surface; 33. Connecting portion; 34. Fifth radial contact surface; 35. Seventh axial contact surface; 40. Sealing joint; 41. Third contact surface; 411. Third axial contact surface; 412. Third radial contact surface; 42. Fourth contact surface; 421. Fourth axial contact surface; 422. Fourth radial contact surface; 43. Sixth axial contact surface; 44. Sixth radial contact surface; 45. Protrusion; 451. Ninth axial contact surface; 50. Cavity; 60. End cover; 70. Annular body limiting space; 80. First annular opening; 90. Second annular opening. Detailed implementation mode

[0019] The embodiments of the present application will be described in detail below. The examples of the embodiments are shown in the drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary and are intended to explain the present application, and should not be construed as a limitation of the present application.

[0020] In the description of the present application, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present application.

[0021] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, "a plurality" means two or more unless otherwise specifically defined.

[0022] In this application, unless otherwise clearly specified and defined, terms such as "installed", "connected", "linked", "fixed", etc. shall be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0023] Embodiment 1 Combine Figure 1 、 Figure 2 and Figure 3As shown, an embodiment of the present application provides a fluid pressure positive feedback sealing positioning structure, which is used in a fluid-driven flexible actuator with a rated working pressure difference upper limit of not less than 50 MPa. The fluid-driven flexible actuator includes a cylindrical flexible side wall 10, and the fluid pressure positive feedback sealing positioning structure includes a fixing member 20, a pressing member 30, and a sealing joint 40 extending from the end of the flexible side wall 10 to between the fixing member 20 and the pressing member 30. The fixing member 20 and the flexible side wall 10 enclose a deformable cavity 50, and the fixing member 20 has a first contact surface 21 arranged facing the cavity 50. The pressing member 30 is arranged in the cavity 50, and the pressing member 30 The invention has a fluid pressure receiving surface 31 disposed back to the fixing member 20 and a second contact surface 32 disposed facing the fixing member 20, the pressing member 30 is connected to the fixing member 20, when the fluid-driven flexible actuator is in the initial state, the sealing joint 40 is squeezed by the pressing member 30 and the fixing member 20 to generate pre-strain, the fixing member 20 and the pressing member 30 include a first material with an elastic modulus greater than 50GPa, the sealing joint 40 includes a second material with an elastic modulus of 10 to 1000MPa and a positive Poisson's ratio, the sealing joint 40 has a third contact surface 41 and a fourth contact surface 42, the third contact surface 41 is sealed with the first contact surface 21 The fourth contact surface 42 is in sealing contact with the second contact surface 32, and the first contact surface 21 and the second contact surface 32 enclose an annular body limiting space 70 with an axially offset opening to partially accommodate the sealing joint 40. The annular body limiting space 70 has a fixed width and a variable height. The height direction of the annular body limiting space 70 is consistent with the axial direction of the flexible side wall 10, and the width direction of the annular body limiting space 70 is consistent with the radial direction of the flexible side wall 10. The annular body limiting space 70 has a first annular opening 80 and a second annular opening 90 that are staggered. The first annular opening 80 is for the sealing joint 40 to connect to the flexible side wall 10, and the second annular opening The opening 90 is arranged between the fixing part 20 and the pressing part 30 along the height direction of the annular body limiting space 70. The sealing joint 40 can completely fit the shape of the annular body limiting space 70 due to pre-strain, thereby cutting off the passage between the cavity 50 and the external environment; when the fluid pressure in the cavity 50 increases, it can act on the fluid pressure bearing surface 31 to make the pressing part 30 move toward the fixing part 20 to reduce the height of the annular body limiting space 70, increase the deformation of the sealing joint 40, thereby increasing the pressure between the sealing joint 40 and the first contact surface 21 and the second contact surface 32, forming a positive feedback relationship between the sealing effect and the fluid pressure.

[0024] It should be noted that the initial state of the fluid-driven flexible actuator refers to the state when the assembly is completed and the pressure difference between the inside and outside of the cavity 50 is zero.

[0025] When the fluid-driven flexible brake is in the initial state, due to the influence of assembly, the sealing joint 40 is extruded by the pressing member 30 and the fixing member 20 to generate a certain pre-strain, and due to this pre-strain, it completely fits the shape of the annular body limiting space 70, so that the third contact surface 41 is in sealing contact with the first contact surface 21, and the fourth contact surface 42 is in sealing contact with the second contact surface 32, so as to cut off the channel between the cavity 50 and the external environment and play a sealing role. When the fluid pressure in the cavity 50 is increased, the fluid pressure along the axial direction of the flexible side wall 10 is received by the fluid pressure receiving surface 31 of the pressing member 30 and transferred to the sealing joint 40 through the pressing member 30. The setting of the second annular opening 90 provides space for the pressing member 30 to move towards the fixing member 20. Under the action of the fluid pressure, the pressing member 30 moves towards the direction close to the fixing member 20 to reduce the height of the annular body limiting space 70 and increase the deformation amount of the sealing joint 40, so as to increase the pressure between the sealing joint 40 and the first contact surface 21 and the second contact surface 32, achieving the effect of enhancing the sealing effect. Moreover, the deformation amount of the sealing joint 40 will increase with the increase of the internal pressure of the cavity 50, showing a positive feedback relationship. The increase in the deformation amount of the sealing joint 40 can make the first contact surface 21 and the third contact surface 41 fit more tightly, and the second contact surface 32 and the fourth contact surface 42 fit more tightly, thus realizing the positive feedback between the sealing reliability and the fluid pressure in the cavity 50, effectively avoiding the problem of sealing failure caused by excessive fluid pressure in the cavity 50. Furthermore, the fixed width of the annular body limiting space 70 can limit the lateral expansion of the sealing joint 40, which is beneficial to increasing the compression amount of the sealing joint 40 along the height direction of the annular body limiting space 70, making the sealing joint 40 fit more tightly with the first contact surface 21 and the second contact surface 32, further enhancing the sealing effect, and thus being beneficial to giving full play to the bearing capacity of the flexible side wall 10 and the fixing member 20 itself so that the fluid-driven flexible actuator has a greater power output capacity. In addition, the elastic modulus of the pressing member 30 and the fixing member 20 is greater than that of the sealing joint 40, that is, the stiffness of the pressing member 30 and the fixing member 20 is greater than that of the sealing joint 40. The sealing joint 40 is shaped and limited from two opposite directions by the pressing member 30 and the fixing member 20 with greater stiffness, which can ensure the shape stability of the sealing joint 40, and thus can effectively control the fluid-driven flexible actuator.

[0026] It should be noted that the above-mentioned fluid can be gas or liquid.

[0027] Furthermore, the sealing joint portion 40 is integrally formed with the flexible side wall 10. By integrally forming the sealing joint portion 40 with the flexible side wall 10, it can ensure that the connection between the sealing joint portion 40 and the flexible side wall 10 is reliable and not easily disconnected, thus ensuring the sealing reliability. In addition, the splicing gap between the sealing joint portion 40 and the flexible side wall 10 can be eliminated, and there is no need to fill the splicing gap between the sealing joint portion 40 and the flexible side wall 10 with sealant, sealing ring, etc. Specifically, the sealing joint portion 40 includes a second material with an elastic modulus of 10 to 1000 MPa and a positive Poisson's ratio. A material with a positive Poisson's ratio refers to a material in which the ratio of the transverse positive strain to the axial positive strain is positive when unidirectionally tensioned or compressed. In other words, when the material is stretched, its transverse direction will shrink, and when the material is compressed, its transverse direction will expand. In this embodiment, when the pressing member 30 and the fixing member 20 cooperate to squeeze the sealing joint portion 40 along the axial direction of the flexible side wall 10, that is, the central axis direction of the cavity 50, the sealing joint portion 40 will generate axial compression in the direction of the central axis of the cavity 50, and at the same time, there is a tendency to expand transversely in the direction perpendicular to the central axis of the cavity 50. However, due to the fixed width of the annular body limiting space 70, the transverse expansion of the sealing joint portion 40 can be restricted. In this way, it is beneficial to increase the axial compression amount of the sealing joint portion 40, making the sealing joint portion 40 fit more closely with the first contact surface 21 and the second contact surface 32, and further enhancing the sealing effect.

[0028] Furthermore, the sealing joint portion 40 includes an outer cladding layer and an inner reinforcing layer disposed within the outer cladding layer. The surface of the outer cladding layer includes a third contact surface 41 and a fourth contact surface 42. The outer cladding layer includes a second material, and the inner reinforcing layer includes a third material with an elastic modulus greater than 1 GPa. The outer cladding layer mainly functions as a seal. It includes a second material with an elastic modulus of 10 - 1000 MPa and can deform when squeezed by the pressing member 30 and the fixing member 20, so that the third contact surface 41 and the fourth contact surface 42 are in close contact with the first contact surface 21 of the fixing member 20 and the second contact surface 32 of the pressing member 30 respectively, thus playing a sealing role. The inner reinforcing layer is disposed inside the outer cladding layer. Its elastic modulus is greater than that of the outer cladding layer. Compared with the outer cladding layer, it has a higher stiffness and stronger ability to resist deformation, thus playing a role in improving the overall strength and structural stability of the sealing joint portion 40, which is beneficial to extending the working life of the sealing joint portion 40. The outer cladding layer and the inner reinforcing layer can be integrally formed by secondary injection molding.

[0029] Furthermore, the sealing joint 40 is located at the edge of the pressing member 30 and extends along the edge contour line of the pressing member 30 to form a closed-loop structure arranged around the central axis of the cavity 50. The pressing member 30 has a connecting portion 33 for connecting the fixing member 20; when the number of the connecting portions 33 is greater than two, the distance between the connecting portion 33 and the edge contour line of the pressing member 30 is less than the distance between any two connecting portions 33. When the pressing member 30 is connected to the fixing member 20 through the connecting portion 33, the pressing member 30 will apply a pressure towards the fixing member 20 to the sealing joint 40 assembled between the pressing member 30 and the fixing member 20, so as to cooperate with the fixing member 20 to squeeze the sealing joint 40, and when the fluid pressure in the cavity 50 is equal to the fluid pressure of the external environment, a certain pre-strain is generated in the sealing joint 40. When the number of the connecting portions 33 is one, the connecting portion 33 can be arranged at the geometric center of the pressing member 30, so that the distances between the connecting portion 33 and each point on the edge contour line of the pressing member 30 are as average as possible, so that the pre-strains of each part of the sealing joint 40 in the direction around the central axis of the cavity 50 are as average as possible, so as to improve the sealing reliability. When the number of the connecting portions 33 is greater than two, the distance between the connecting portion 33 and the edge contour line of the pressing member 30 is made less than the distance between any two connecting portions 33, so as to reduce the distance between the connecting portion 33 and the edge contour line of the pressing member 30, that is, to make the connecting portion 33 closer to the sealing joint 40, so that when the pressing member 30 is connected to the fixing member 20 through the connecting portion 33, the squeezing force generated by the cooperation of the pressing member 30 and the fixing member 20 can act more concentratedly on the sealing joint 40, so as to improve the sealing reliability.

[0030] Further, the connecting portion 33 can be a threaded hole, and a through hole 22 is provided at the position of the fixing member 20 corresponding to the threaded hole. The fluid pressure positive feedback sealing and positioning structure further includes a threaded fastener. The threaded fastener passes through the through hole 22 and is threadedly connected to the threaded hole, so as to realize that the pressing member 30 and the fixing member 20 cooperate to clamp the sealing joint portion 40. More specifically, the threaded fastener includes a connected head and a rod portion. The diameter of the head is larger than the diameter of the rod portion and the diameter of the through hole 22. An external thread is provided on the rod portion. After the rod portion passes through the through hole 22, it is threadedly connected to the threaded hole. When the fluid pressure in the cavity 50 is equal to the fluid pressure of the external environment, the head abuts against the side of the fixing member 20 facing away from the pressing member 30, so as to realize that the pressing member 30 and the fixing member 20 cooperate to clamp the sealing joint portion 40. When the fluid pressure in the cavity 50 increases, the fluid pressure in the cavity 50 acts on the fluid pressure receiving surface 31 of the pressing member 30, causing the pressing member 30 to move in the direction close to the fixing member 20 to reduce the distance between the pressing member 30 and the fixing member 20, thereby increasing the deformation amount of the sealing joint portion 40. Since the rod portion of the threaded fastener is locked with the threaded hole of the pressing member 30, the pressing member 30 will drive the threaded fastener to move together, causing the head of the threaded fastener to separate from the pressing member 30. When the fluid pressure in the cavity 50 becomes smaller and is equal to the fluid pressure of the external environment again, the sealing joint portion 40 returns to its original state and pushes the pressing member 30 to move away from the fixing member 20 to realize resetting, and the head of the threaded fastener abuts against the fixing member 20 again.

[0031] Furthermore, the annular body limiting space 70 is in the shape of a circular cylinder. The first contact surface 21 includes a first axial contact surface 211 and a first radial contact surface 212. The first axial contact surface 211 is perpendicular to the central axis of the cavity 50. The first radial contact surface 212 is perpendicular to the first axial contact surface 211. The first radial contact surface 212 is connected to the side of the first axial contact surface 211 away from the central axis of the cavity 50 and is located on the side of the first axial contact surface 211 close to the pressing member 30. The second contact surface 32 includes a second axial contact surface 321 and a second radial contact surface 322. The second axial contact surface 321 is parallel to the first axial contact surface 211. The second radial contact surface 322 is perpendicular to the second axial contact surface 321. The second radial contact surface 322 is connected to the side of the second axial contact surface 321 close to the central axis of the cavity 50 and is located on the side of the second axial contact surface 321 close to the fixing member 20. The third axial contact surface 411 includes a third axial contact surface 411 and a third radial contact surface 412. The third axial contact surface 411 is in sealing abutment with the first axial contact surface 211. The third radial contact surface 412 is perpendicular to the third axial contact surface 411. The third radial contact surface 412 is connected to the side of the third axial contact surface 411 away from the central axis of the cavity 50 and is located on the side of the third axial contact surface 411 close to the pressing member 30. The third radial contact surface 412 is used for sealing abutment with the first radial contact surface 212. The fourth contact surface 42 includes a fourth axial contact surface 421 and a fourth radial contact surface 422. The fourth axial contact surface 421 is in sealing abutment with the second axial contact surface 321. The fourth radial contact surface 422 is perpendicular to the fourth axial contact surface 421. The fourth radial contact surface 422 is connected to the side of the fourth axial contact surface 421 close to the central axis of the cavity 50 and is located on the side of the fourth axial contact surface 421 close to the fixing member 20. The fourth radial contact surface 422 is used for sealing abutment with the second radial contact surface 322.

[0032] By dividing the first contact surface 21 into a first axial contact surface 211 and a first radial contact surface 212, dividing the second contact surface 32 into a second axial contact surface 321 and a second radial contact surface 322, dividing the third contact surface 41 into a third axial contact surface 411 and a third radial contact surface 412, and dividing the fourth contact surface 42 into a fourth axial contact surface 421 and a fourth radial contact surface 422, the first axial contact surface 211 is in sealing abutment with the third axial contact surface 411, the second axial contact surface 321 is in sealing abutment with the fourth axial contact surface 421, the first radial contact surface 212 is in sealing abutment with the third radial contact surface 412, and the second radial contact surface 322 is in sealing abutment with the fourth radial contact surface 422. Thus, the sealing effect can be achieved in two different directions, namely the axial direction and the radial direction, so as to improve the reliability of the seal. The above-mentioned axial direction refers to the direction along the central axis of the cavity 50, and the radial direction refers to the direction perpendicular to the central axis of the cavity 50. In addition, the cooperation between the first axial contact surface 211 and the second axial contact surface 321 can play a limiting role in the axial direction for the sealing joint portion 40, and the cooperation between the first radial contact surface 212 and the second radial contact surface 322 can play a limiting role in the radial direction for the sealing joint portion 40. In this way, the shape stability of the sealing joint portion 40 can be ensured, and thus the fluid-driven flexible actuator can be effectively controlled.

[0033] Further, the second radial contact surface 322 is an equi-width cylindrical surface with a width of L1, and the distance between the first radial contact surface 212 and the second radial contact surface 322 is L2; when the sealing joint 40 is not deformed, the distance between the third axial contact surface 411 and the fourth axial contact surface 421 is D1, and the distance between the third radial contact surface 412 and the fourth radial contact surface 422 is D2, 1.2L1 < D1 < 2L1, 1.05D2 < L2 < 1.2D2; when the fluid-driven flexible actuator is in the initial state, that is, the state when the assembly is completed and the pressure difference inside and outside the cavity 50 is 0, the distance between the third axial contact surface 411 and the fourth axial contact surface 421 is D3, 0.7D2 < D3 < D2. During assembly, the fixing member 20 and the pressing member 30 cooperate to squeeze the sealing joint 40, which will cause the sealing joint 40 to be compressed axially and expanded radially, that is, the distance between the third axial contact surface 411 and the fourth axial contact surface 421 is reduced, while the distance between the third radial contact surface 412 and the fourth radial contact surface 422 is increased, so that the third radial contact surface 412 and the fourth radial contact surface 422 are respectively in sealing contact with the first radial contact surface 212 and the second radial contact surface 322. By designing 1.2L1 < D1 < 2L1, 1.05D2 < L2 < 1.2D2, space can be provided for the deformation of the sealing joint 40 during assembly, so that the sealing joint 40 generates a certain pre-deformation amount to ensure the initial sealing effect, and at the same time, the direct contact between the fixing member 20 and the pressing member 30 is avoided. By controlling 0.7D2 < D3 < D2, the structural and dimensional stability of the sealing joint 40 can be better maintained, and the sealing failure caused by local damage due to excessive pressure is avoided.

[0034] The shape of the second radial contact surface 322 is not specifically limited. Exemplarily, the second radial contact surface 322 can be a cylindrical surface, an elliptical cylindrical surface, a racetrack-shaped cylindrical surface, etc. When the second radial contact surface 322 is a cylindrical surface, the shape of the second axial contact surface 321 can correspond to an annular shape. When the second radial contact surface 322 is an elliptical cylindrical surface, the shape of the second axial contact surface 321 can correspond to an elliptical annular shape. When the second radial contact surface 322 is a racetrack-shaped cylindrical surface, the shape of the second axial contact surface 321 can correspond to a racetrack annular shape. The shape of the fourth radial contact surface 422 is adapted to the shape of the second radial contact surface 322 to increase the contact area between the fourth radial contact surface 422 and the second radial contact surface 322, thereby enhancing the sealing effect. The shape of the fourth axial contact surface 421 is adapted to the shape of the second axial contact surface 321 to increase the contact area between the fourth axial contact surface 421 and the second axial contact surface 321, thereby enhancing the sealing effect.

[0035] Furthermore, the fixing member 20 further has a fifth axial contact surface 23, the fifth axial contact surface 23 is perpendicular to the first radial contact surface 212, the fifth axial contact surface 23 is connected to the side of the first radial contact surface 212 away from the first axial contact surface 211, and is located on the side of the first radial contact surface 212 away from the central axis of the cavity 50; the pressing member 30 further has a fifth radial contact surface 34, the fifth radial contact surface 34 is perpendicular to the second axial contact surface 321, the fifth radial contact surface 34 is connected to the side of the second axial contact surface 321 away from the second radial contact surface 322, and is located on the side of the second axial contact surface 321 away from the fixing member 20; the sealing joint 40 further has a sixth axial contact surface 43 and a sixth radial contact surface 44, the sixth axial contact surface 43 is perpendicular to the third radial contact surface 412, the sixth axial contact surface 43 is connected to the side of the third radial contact surface 412 away from the third axial contact surface 411, and is located on the side of the third radial contact surface 412 away from the central axis of the cavity 50, the sixth axial contact surface 43 is in sealing abutment with the fifth axial contact surface 23; the sixth radial contact surface 44 is perpendicular to the fourth axial contact surface 421, the sixth radial contact surface 44 is connected to the side of the fourth axial contact surface 421 away from the fourth radial contact surface 422, and is located on the side of the fourth axial contact surface 421 away from the fixing member 20, the sixth radial contact surface 44 is in sealing abutment with the fifth radial contact surface 34. By providing the fifth axial contact surface 23 on the fixing member 20, the fifth radial contact surface 34 on the pressing member 30, and the sixth axial contact surface 43 and the sixth radial contact surface 44 on the sealing joint 40, the fifth axial contact surface 23 is in sealing abutment with the sixth axial contact surface 43, and the fifth radial contact surface 34 is in sealing abutment with the sixth radial contact surface 44, so that the contact areas between the fixing member 20 and the sealing joint 40, and between the pressing member 30 and the sealing joint 40 can be further increased, thereby improving the sealing reliability. Specifically, when the fluid pressure in the cavity 50 is equal to the fluid pressure in the external environment, due to the influence of assembly, the fifth axial contact surface 23 and the sixth axial contact surface 43 are already in a state of sealing abutment, and the fifth radial contact surface 34 and the sixth radial contact surface 44 are already in a state of sealing abutment.

[0036] Embodiment 2 As Figure 1 shown, an embodiment of the present application provides a fluid-driven robot module, including a flexible side wall 10 and the fluid pressure positive feedback sealing and positioning structure provided in Embodiment 1.

[0037] By applying the fluid pressure positive feedback sealing and positioning structure provided in the first embodiment, when the fluid pressure in the cavity 50 is increased, the fluid pressure along the axial direction of the flexible sidewall 10 is received by the fluid pressure receiving surface 31 of the pressing member 30 and transferred to the sealing joint 40 through the pressing member 30. The setting of the second annular opening 90 provides space for the pressing member 30 to move towards the fixing member 20. Under the action of the fluid pressure, the pressing member 30 moves towards the fixing member 20 to reduce the height of the annular body limiting space 70, increasing the deformation amount of the sealing joint 40, thereby increasing the pressure between the sealing joint 40 and the first contact surface 21 and the second contact surface 32, achieving the effect of enhancing the sealing effect. Moreover, the deformation amount of the sealing joint 40 increases with the increase of the internal pressure of the cavity 50, showing a positive feedback relationship. The increase in the deformation amount of the sealing joint 40 enables the first contact surface 21 to fit more closely with the third contact surface 41 and the second contact surface 32 to fit more closely with the fourth contact surface 42, thus realizing the positive feedback between the sealing reliability and the fluid pressure in the cavity 50, effectively avoiding the problem of sealing failure caused by excessive fluid pressure inside the cavity 50. In addition, the fixed width of the annular body limiting space 70 can limit the lateral expansion of the sealing joint 40, which is beneficial to increasing the compression amount of the sealing joint 40 along the height direction of the annular body limiting space 70, making the sealing joint 40 fit more closely with the first contact surface 21 and the second contact surface 32, further enhancing the sealing effect, and thus being beneficial to giving full play to the bearing capacity of the flexible sidewall 10 and the fixing member 20 itself to enable the fluid-driven flexible actuator to have a greater power output capacity. Additionally, the elastic modulus of the pressing member 30 and the fixing member 20 is greater than that of the sealing joint 40, that is, the stiffness of the pressing member 30 and the fixing member 20 is greater than that of the sealing joint 40. The sealing joint 40 is shaped and limited from two opposite directions by the pressing member 30 and the fixing member 20 with greater stiffness, which can ensure the shape stability of the sealing joint 40, thereby enabling effective control of the fluid-driven flexible actuator.

[0038] The outer contour shape of the cross-section of the flexible sidewall 10 can be circular, elliptical, square, fan-shaped, irregular, etc. Additionally, when the flexible sidewall 10 is in a cylindrical shape, both axial ends of the flexible sidewall 10 have openings. The fixing member 20 is arranged at one of the openings of the flexible sidewall 10. The fluid-driven flexible actuator further includes an end cap 60, and the end cap 60 is arranged at the other opening of the flexible sidewall 10. The flexible sidewall 10, the fixing member 20, and the end cap 60 jointly enclose a deformable cavity 50.

[0039] The fixing member 20 is provided with a fluid passing hole 25 communicating with the cavity 50. The fluid-driven flexible actuator further includes a power device connected to the fluid passing hole 25. The power device is configured to drive the fluid in the external environment to enter the cavity 50 through the fluid passing hole 25, or drive the fluid in the cavity 50 to be discharged to the external environment through the fluid passing hole 25, so as to change the pressure of the fluid in the cavity 50, thereby causing the cavity 50 to deform.

[0040] The flexible side wall 10 includes a strain-uniform stacking structure that can be folded and / or extended along the central axis direction of the cavity 50. The strain-uniform stacking structure includes at least two strain-uniform stacking layers stacked along the central axis direction of the cavity 50. The strain-uniform stacking layer is enclosed by a single folding surface 11. The connection part of the folding surfaces 11 of two adjacent strain-uniform stacking layers forms a crease 12. The surface where the crease 12 is located is a plane and perpendicular to the central axis of the cavity 50. The included angle between the folding surface 11 adjacent to the sealing joint 40 and the plane passing through any point on the sealing joint 40 and perpendicular to the central axis on the side facing the central axis of the cavity 50 is α, where α < 60° or α > 120°. During operation, when the pressure of the fluid in the cavity 50 increases, the flexible side wall 10 can extend along the central axis direction of the cavity 50, and the space of the cavity 50 becomes larger accordingly; conversely, when the pressure of the fluid in the cavity 50 decreases, the flexible side wall 10 can fold along the central axis direction of the cavity 50, and the space of the cavity 50 becomes smaller accordingly. By designing the surface where the crease 12 between the folding surfaces 11 of two adjacent strain-uniform stacking layers is a plane and perpendicular to the central axis of the cavity 50, it is ensured that the flexible side wall 10 can be stably folded or telescoped along the central axis direction of the cavity 50. By designing α < 60° or α > 120°, the structural stability of the flexible side wall 10 can be ensured, and the flexible side wall 10 can be prevented from protruding and deforming outward under the high pressure of the fluid inside the cavity 50, thereby changing the shape of the sealing joint 40 and affecting the sealing effect.

[0041] Embodiment III Combination Figure 4 、 Figure 5 And Figure 6As shown in the figure, this embodiment provides another fluid pressure positive feedback seal positioning structure. The differences from the fluid pressure positive feedback seal positioning structure provided in the first embodiment include: The pressing member 30 further has a seventh axial contact surface 35, which is perpendicular to the second radial contact surface 322. The seventh axial contact surface 35 is connected to the side of the second radial contact surface 322 away from the second axial contact surface 321 and is located on the side of the second radial contact surface 322 close to the central axis of the cavity 50. When the fluid-driven flexible actuator is in the initial state, that is, the state after assembly and when the pressure difference inside and outside the cavity 50 is 0, the seventh axial contact surface 35 is spaced apart from the first axial contact surface 211, providing space for the deformation of the seal joint 40. The first axial contact surface 211 is locally recessed to form an avoidance groove 24, and the avoidance groove 24 completely covers the seventh axial contact surface 35 along the direction of the central axis of the cavity 50, so that the seventh axial contact surface 35 and the first axial contact surface 211 are completely staggered in the direction perpendicular to the central axis of the cavity 50. When the fluid pressure in the cavity 50 increases, the deformation amount of the seal joint 40 increases, and the gap between the seventh axial contact surface 35 and the first axial contact surface 211 decreases. When the deformation amount of the seal joint 40 is too large, the seventh axial contact surface 35 can enter the avoidance groove 24 without colliding with the first axial contact surface 211, thereby avoiding rigid collision between the fixing member 20 and the pressing member 30.

[0042] Further, a convex portion 45 is formed by locally protruding the third axial contact surface 411 of the seal joint 40. The convex portion 45 extends into the avoidance groove 24. The bottom of the avoidance groove 24 has an eighth axial contact surface 241 perpendicular to the central axis of the cavity 50. One side of the convex portion 45 facing the eighth axial contact surface 241 has a ninth axial contact surface 451 parallel to the eighth axial contact surface 241. The ninth axial contact surface 451 is used for sealing abutment with the eighth axial contact surface 241 to enhance the sealing effect. When the fluid pressure in the cavity 50 is equal to the fluid pressure of the external environment, the eighth axial contact surface 241 and the ninth axial contact surface 451 may already be in a state of sealing abutment or in a separated state. For the latter, as the fluid pressure in the cavity 50 increases, the seal joint 40 continuously deforms, and the ninth axial contact surface 451 will gradually approach the eighth axial contact surface 241. When the fluid pressure in the cavity 50 reaches a certain level, the ninth axial contact surface 451 and the eighth axial contact surface 241 are in sealing abutment.

[0043] The rest of this embodiment is the same as that of the first embodiment. For the features not explained in this embodiment, the explanations of the first embodiment are adopted and will not be elaborated here.

[0044] Embodiment Four As Figure 6As shown in the figure, the embodiment of the present application further provides a fluid-driven robot module, which includes a flexible sidewall 10 and the fluid pressure positive feedback sealing and positioning structure provided in Embodiment III.

[0045] By applying the fluid pressure positive feedback sealing and positioning structure provided in Embodiment III, when the fluid pressure in the cavity 50 is increased, the fluid pressure along the axial direction of the flexible sidewall 10 will be received by the fluid pressure receiving surface 31 of the pressing member 30 and transferred to the sealing joint 40 through the pressing member 30. The setting of the second annular opening 90 provides space for the pressing member 30 to move towards the fixing member 20. Under the action of the fluid pressure, the pressing member 30 moves towards the fixing member 20 to reduce the height of the annular body limiting space 70, increase the deformation amount of the sealing joint 40, thereby increasing the pressure between the sealing joint 40 and the first contact surface 21 and the second contact surface 32, achieving the effect of enhancing the sealing effect. And the deformation amount of the sealing joint 40 will increase with the increase of the internal pressure of the cavity 50, showing a positive feedback relationship. The increase in the deformation amount of the sealing joint 40 can make the first contact surface 21 and the third contact surface 41 fit more closely, and make the second contact surface 32 and the fourth contact surface 42 fit more closely, thus realizing the positive feedback between the sealing reliability and the fluid pressure in the cavity 50, effectively avoiding the problem of sealing failure caused by excessive fluid pressure in the cavity 50. Moreover, the fixed width of the annular body limiting space 70 can limit the lateral expansion of the sealing joint 40, which is beneficial to increasing the compression amount of the sealing joint 40 along the height direction of the annular body limiting space 70, making the sealing joint 40 fit more closely with the first contact surface 21 and the second contact surface 32, further enhancing the sealing effect, and thus being beneficial to giving full play to the bearing capacity of the flexible sidewall 10 and the fixing member 20 itself so that the fluid-driven flexible actuator has a greater power output capacity. In addition, the elastic modulus of the pressing member 30 and the fixing member 20 is greater than the elastic modulus of the sealing joint 40, that is, the stiffness of the pressing member 30 and the fixing member 20 is greater than the stiffness of the sealing joint 40. The sealing joint 40 is shaped and limited from two opposite directions by the pressing member 30 and the fixing member 20 with greater stiffness, which can ensure the shape stability of the sealing joint 40, and thus can effectively control the fluid-driven flexible actuator.

[0046] The outer contour shape of the cross-section of the flexible sidewall 10 can be circular, elliptical, square, fan-shaped, irregular, etc. In addition, when the flexible sidewall 10 is in a cylindrical shape, both axial ends of the flexible sidewall 10 have openings. The fixing member 20 is arranged at one of the openings of the flexible sidewall 10. The fluid-driven flexible actuator further includes an end cap 60, and the end cap 60 is arranged at the other opening of the flexible sidewall 10. The flexible sidewall 10, the fixing member 20 and the end cap 60 jointly enclose a deformable cavity 50.

[0047] The fixing member 20 is provided with a fluid through hole 25 connected to the cavity 50. The fluid-driven flexible actuator also includes a power device, which is connected to the fluid through hole 25. The power device is used to drive the fluid in the external environment to enter the cavity 50 through the fluid through hole 25, or to drive the fluid in the cavity 50 to be discharged into the external environment through the fluid through hole 25, so as to change the pressure of the fluid in the cavity 50, thereby causing the cavity 50 to deform.

[0048] The flexible side wall 10 includes a strain-uniformly distributed stacking structure that can be folded and / or stretched along the direction of the central axis of the cavity 50. The strain-uniformly distributed stacking structure includes at least two strain-uniformly distributed stacking layers stacked along the direction of the central axis of the cavity 50. The strain-uniformly distributed stacking layers are enclosed by a single folding surface 11. The connection of the folding surfaces 11 of two adjacent strain-uniformly distributed stacking layers forms a fold 12. The surface where the fold 12 is located is a plane and is perpendicular to the central axis of the cavity 50. The angle between the folding surface 11 adjacent to the sealing joint 40 and the plane passing through any point on the sealing joint 40 and perpendicular to the central axis on the side facing the central axis of the cavity 50 is α, α < 60° or α > 120°. During operation, when the pressure of the fluid in the cavity 50 is increased, the flexible side wall 10 can stretch along the central axis of the cavity 50, and the space of the cavity 50 becomes larger; on the contrary, when the pressure of the fluid in the cavity 50 is reduced, the flexible side wall 10 can fold along the central axis of the cavity 50, and the space of the cavity 50 becomes smaller. By designing the surface where the fold 12 between the folding surfaces 11 of two adjacent uniformly distributed strain stacking layers is located as a plane and making it perpendicular to the central axis of the cavity 50, it is ensured that the flexible side wall 10 can be stably folded or stretched along the direction of the central axis of the cavity 50. By designing α<60° or α>120°, the structural stability of the flexible side wall 10 can be ensured, and the flexible side wall 10 is prevented from protruding outward and deforming under the high pressure of the fluid inside the cavity 50, thereby changing the shape of the sealing joint 40 and affecting the sealing effect.

[0049] It should be noted that the above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A fluid pressure positive feedback sealing positioning structure, used in a fluid-driven flexible actuator with a rated working pressure difference upper limit of not less than 50 MPa, the fluid-driven flexible actuator comprising a cylindrical flexible side wall (10), the fluid pressure positive feedback sealing positioning structure is characterized in that the fluid pressure positive feedback sealing positioning structure comprises a fixing member (20), a pressing member (30), and a sealing joint (40) extending from the end of the flexible side wall (10) to between the fixing member (20) and the pressing member (30), the fixing member (20) and the flexible side wall (10) enclosing a deformable cavity (50), the fixing member (20) having a The present invention relates to a fluid-driven flexible actuator having a first contact surface (21) arranged facing the cavity (50), the pressing piece (30) being arranged in the cavity (50), the pressing piece (30) having a fluid pressure receiving surface (31) arranged facing away from the fixing piece (20) and a second contact surface (32) arranged facing the fixing piece (20), the pressing piece (30) being connected to the fixing piece (20), and when the fluid-driven flexible actuator is in an initial state, the sealing joint (40) is squeezed by the pressing piece (30) and the fixing piece (20) to generate pre-strain, and the fixing piece (20) and the pressing piece (30) have an elastic modulus greater than 50 GPa. The sealing joint (40) comprises a first material having an elastic modulus of 10 to 1000 MPa and a positive Poisson's ratio, the sealing joint (40) comprising a third contact surface (41) and a fourth contact surface (42), the third contact surface (41) being in sealing contact with the first contact surface (21), the fourth contact surface (42) being in sealing contact with the second contact surface (32), the first contact surface (21) and the second contact surface (32) enclosing an annular body limiting space (70) with an axially offset opening to partially accommodate the sealing joint (40), the annular body limiting space (70) having a fixed width and a variable height, the annular body limiting space (70) having a fixed width and a variable height, The height direction of the space (70) is consistent with the axial direction of the flexible side wall (10), and the annular body limiting space (70) has a first annular opening (80) and a second annular opening (90) which are staggered. The first annular opening (80) is provided for the sealing joint (40) to connect to the flexible side wall (10), and the second annular opening (90) is provided between the fixing part (20) and the pressing part (30) along the height direction of the annular body limiting space (70). Due to the pre-strain, the sealing joint (40) can completely fit the shape of the annular body limiting space, thereby cutting off the passage between the cavity (50) and the external environment;When the fluid pressure in the cavity (50) increases, it can act on the fluid pressure receiving surface (31), causing the pressing member (30) to move towards the fixing member (20), thereby reducing the height of the annular body limiting space and increasing the deformation of the sealing joint portion (40). As a result, the pressure between the sealing joint portion (40) and the first contact surface (21) and the second contact surface (32) is increased, forming a positive feedback relationship between the sealing effect and the fluid pressure.

2. The fluid pressure positive feedback sealing and positioning structure according to claim 1, wherein: The sealed joint part (40) is integrally formed with the flexible side wall (10).

3. The fluid pressure positive feedback sealing and positioning structure according to claim 1, wherein: The sealed joint part (40) includes an outer cladding layer and an inner reinforcing layer disposed within the outer cladding layer. The surface of the outer cladding layer includes the third contact surface (41) and the fourth contact surface (42). The outer cladding layer includes the second material, and the inner reinforcing layer includes a third material with an elastic modulus greater than 1 GPa.

4. The fluid pressure positive feedback seal positioning structure according to claim 1, characterized in that: The sealed joint part (40) is located at the edge of the pressing part (30) and extends along the edge contour line of the pressing part (30) to form a closed-loop structure arranged around the central axis of the cavity (50). The pressing part (30) has a connecting part (33) for connecting the fixing part (20); when the number of the connecting parts (33) is greater than two, the distance between the connecting part (33) and the edge contour line of the pressing part (30) is less than the distance between two of the connecting parts (33).

5. The fluid pressure positive feedback seal positioning structure according to claim 1, wherein: The annular body limiting space is in the shape of a circular cylinder. The first contact surface (21) includes a first axial contact surface (211) and a first radial contact surface (212) that are perpendicularly connected; the second contact surface (32) includes a second axial contact surface (321) and a second radial contact surface (322) that are perpendicularly connected; the third contact surface (41) includes a third axial contact surface (411) and a third radial contact surface (412) that are perpendicularly connected. The third axial contact surface (411) is in sealing contact with the first axial contact surface (211), and the third radial contact surface (412) is in sealing contact with the first radial contact surface (212); the fourth contact surface (42) includes a fourth axial contact surface (421) and a fourth radial contact surface (422) that are perpendicularly connected. The fourth axial contact surface (421) is in sealing contact with the second axial contact surface (321), and the fourth radial contact surface (422) is in sealing contact with the second radial contact surface (322).

6. The fluid pressure positive feedback seal positioning structure according to claim 5, wherein: The second radial contact surface (322) is a cylindrical surface with a constant width of L1. The distance between the first radial contact surface (212) and the second radial contact surface (322) is L2; when the sealed joint part (40) is not deformed, the distance between the third axial contact surface (411) and the fourth axial contact surface (421) is D1, and the distance between the third radial contact surface (412) and the fourth radial contact surface (422) is D2, where 1.2L1 < D1 < 2L1 and 1.05D2 < L2 < 1.2D2; when the fluid-driven flexible actuator is in the initial state, the distance between the third axial contact surface (411) and the fourth axial contact surface (421) is D3, where 0.7D2 < D3 < D2.

7. The fluid pressure positive feedback sealing and positioning structure according to claim 5, characterized in that: The second radial contact surface (322) is a cylindrical surface, an elliptical cylindrical surface or a racetrack-shaped cylindrical surface. The second axial contact surface (321) is in an annular shape, an elliptical annular shape or a racetrack annular shape. The shape of the fourth radial contact surface (422) is adapted to the shape of the second radial contact surface (322), and the shape of the fourth axial contact surface (421) is adapted to the shape of the second axial contact surface (321).

8. The fluid pressure positive feedback sealing and positioning structure according to claim 5, characterized in that: The fixing member (20) further has a fifth axial contact surface (23). The fifth axial contact surface (23) is perpendicular to the first radial contact surface (212). The fifth axial contact surface (23) and the first axial contact surface (211) are respectively connected to opposite sides of the first radial contact surface (212). The pressing member (30) further has a fifth radial contact surface (34). The fifth radial contact surface (34) is perpendicular to the second axial contact surface (321). The fifth radial contact surface (34) and the second radial contact surface (322) are respectively connected to opposite sides of the second axial contact surface (321). The sealing joint portion (40) further has a sixth axial contact surface (43) and a sixth radial contact surface (44). The sixth axial contact surface (43) is perpendicularly connected to the third radial contact surface (412) and is in sealing abutment with the fifth axial contact surface (23). The sixth radial contact surface (44) is perpendicularly connected to the fourth axial contact surface (421) and is in sealing abutment with the fifth radial contact surface (34).

9. A fluid-driven robot module, characterized in that, It includes a flexible side wall (10) and the fluid pressure positive feedback sealing and positioning structure according to any one of claims 1-8.

10. The fluid-driven robot module according to claim 9, wherein: The flexible side wall (10) includes a strain-uniform stacking structure that can be folded and / or extended along the central axis direction of the cavity (50). The strain-uniform stacking structure includes at least two strain-uniform stacking layers stacked along the central axis direction of the cavity (50). The strain-uniform stacking layer is enclosed by a single folding surface (11). The connection of the folding surfaces (11) of two adjacent strain-uniform stacking layers forms a crease (12). The surface where the crease (12) is located is a plane and is perpendicular to the central axis of the cavity (50). The folding surface (11) adjacent to the sealing joint portion (40) and the plane passing through any point on the sealing joint portion (40) and perpendicular to the central axis form an angle α on the side facing the central axis of the cavity (50), and α < 60° or α > 120°.

Images