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

Abstract

The present application belongs to the field of flexible brake technology, and specifically provides a fluid pressure positive feedback sealing positioning structure and a fluid-driven robot module. The fluid-driven robot module includes a flexible side wall and a fluid pressure positive feedback sealing positioning structure. The fluid pressure positive feedback sealing positioning structure includes a fixing part, a pressing part, and a sealing joint extending from 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 sealing joint is squeezed by the pressing part and the fixing part to generate pre-strain. When the fluid pressure in the cavity increases, it can act on the pressing part, and the deformation of the sealing joint is increased through the pressing part, thereby improving the sealing reliability, effectively avoiding the problem of sealing failure caused by excessive fluid pressure inside the cavity, thereby facilitating full utilization of the bearing capacity of the flexible side wall and the fixing part itself so that the fluid-driven flexible actuator has greater 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, electricity, magnetism, or chemical reactions into mechanical work. A key component of soft robots and wearable devices, it primarily responds to external stimuli and utilizes special structures or materials to produce changes in size and shape, enabling reversible movements such as movement or shaping to achieve functions such as bending, grasping, and locomotion. Pneumatic flexible actuators, on the other hand, achieve movement through gas and typically include a flexible cavity. By inflating and deflating the cavity, they can achieve movements such as extension and bending. The power output capacity of a pneumatic flexible actuator is positively correlated with the fluid pressure within the flexible cavity. A pneumatic flexible actuator typically includes a flexible sidewall and other components sealed to the ends of the flexible sidewall. The flexible sidewall and other components enclose a flexible cavity. The internal fluid pressure that a pneumatic flexible actuator can withstand depends on the bearing capacity of the flexible sidewall itself, the bearing capacity of the other components, and the sealing between them. Currently, the inherent strength of the flexible sidewall and other components is no longer a bottleneck in the power output capacity of pneumatic flexible actuators. However, the sealing effect of the flexible cavity of current pneumatic flexible actuators is not ideal. Excessive fluid pressure within the cavity often leads to seal failure. Furthermore, the greater the fluid pressure within the cavity, the more severe the leakage problem. Consequently, the bearing capacity of the flexible sidewall and other components cannot be fully utilized to achieve a higher power output capacity. Furthermore, the shape stability of the flexible sidewall end is a prerequisite for effective control of the flexible actuator. Unexpected deformation under high or low pressure (such as abnormal local bulging under high pressure or abnormal local collapse under low pressure) can cause control failure and prevent the intended operation from being performed. Summary of the Invention

[0003] The purpose of this 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, in order to achieve the above-mentioned purpose, the technical solution adopted in the present application is: 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, and 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 the 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 50 GPa, the sealing joint includes a second material with an elastic modulus of 10 to 1000 MPa and a positive Poisson's ratio, and the sealing joint The invention provides a third contact surface and a fourth contact surface, the third contact surface is in sealing contact with the first contact surface, the fourth contact surface is in sealing contact with 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 the 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 effect of the fluid pressure positive feedback sealing result provided by the present application is that: when the fluid-driven flexible brake is in the initial state, the sealing joint is squeezed by the pressing parts and the fixing parts due to the influence of the assembly, and a certain pre-strain is generated. Moreover, due to the pre-strain, it completely fits the shape of the annular body limiting space, so that the third contact surface is sealed against the first contact surface, and the fourth contact surface is sealed against the second contact surface, so as to cut off the channel between the cavity and the external environment, thereby playing a sealing role. When the fluid pressure in the cavity is increased, the fluid pressure along the axial direction of the flexible side wall will be taken up by the fluid pressure bearing surface of the pressing part and transferred to the sealing joint through the pressing part. The setting of the second annular opening provides space for the pressing part to move toward the fixed part. Under the action of the fluid pressure, the pressing part moves toward the fixed 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, thereby enhancing the sealing effect. The deformation 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 of the sealing joint can make the first contact surface and the The third contact surface is more closely fitted, and the second contact surface and the fourth contact surface are more closely fitted, thereby achieving positive feedback between the sealing reliability and the fluid pressure in the cavity, effectively avoiding the problem of sealing failure due to excessive fluid pressure inside the cavity. Moreover, the fixed width of the annular body limiting space can limit the lateral expansion of the sealing joint, which is conducive to increasing the compression 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, further enhancing the sealing effect, thereby facilitating full utilization of the bearing capacity of the flexible side wall and the fixing part itself so that the fluid-driven flexible actuator has a greater power output capacity. In addition, the elastic modulus of the pressing part and the fixing part is greater than the elastic modulus of the sealing joint, that is, the stiffness of the pressing part and the fixing part is greater than the stiffness of the sealing joint. The sealing joint is shaped and limited from two opposite directions by the pressing part and the fixing part with greater stiffness, which can ensure the shape stability of the sealing joint, thereby effectively controlling the fluid-driven flexible actuator.

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

[0007] Furthermore, the sealing joint includes an outer covering layer and an inner reinforcement layer arranged in the outer covering layer, the surface of the outer covering layer includes a third contact surface and a fourth contact surface, the outer covering layer includes a second material, and the inner reinforcement 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 does not deform, 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, and the fifth axial contact surface and the first axial contact surface are respectively connected to the opposite sides of the first radial contact surface;

[0013] The pressing member further has a fifth radial contact surface that is perpendicular to the second axial contact surface, and the fifth radial contact surface and the second radial contact surface are respectively connected to the opposite sides of the second axial contact surface;

[0014] 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.

[0015] On the other hand, in order to achieve the above-mentioned purpose, the technical solution adopted in this application is: a fluid-driven robot module, including a flexible side wall and the above-mentioned fluid pressure positive feedback sealing and positioning structure.

[0016] Compared with the prior art, the beneficial effect of the fluid-driven robot module provided by the present application is that: by applying the above-mentioned fluid pressure positive feedback sealing positioning structure, when the fluid-driven flexible brake is in the initial state, the sealing joint is squeezed by the pressing parts and the fixing parts due to the influence of the assembly and produces a certain pre-strain, and due to the pre-strain, it completely fits the shape of the annular body limiting space, so that the third contact surface is sealed against the first contact surface, and the fourth contact surface is sealed against the second contact surface, so as to cut off the channel between the cavity and the external environment, thereby playing a sealing role. When the fluid pressure in the cavity is increased, the fluid pressure along the axial direction of the flexible side wall will be taken up by the fluid pressure bearing surface of the pressing part and transferred to the sealing joint through the pressing part. The setting of the second annular opening provides space for the pressing part to move toward the fixed part. Under the action of the fluid pressure, the pressing part moves toward the fixed 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, thereby enhancing the sealing effect. The deformation 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 of the sealing joint can make the first contact surface and the The third contact surface is more closely fitted, and the second contact surface and the fourth contact surface are more closely fitted, thereby achieving positive feedback between the sealing reliability and the fluid pressure in the cavity, effectively avoiding the problem of sealing failure due to excessive fluid pressure inside the cavity. Moreover, the fixed width of the annular body limiting space can limit the lateral expansion of the sealing joint, which is conducive to increasing the compression 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, further enhancing the sealing effect, thereby facilitating full utilization of the bearing capacity of the flexible side wall and the fixing part itself so that the fluid-driven flexible actuator has a greater power output capacity. In addition, the elastic modulus of the pressing part and the fixing part is greater than the elastic modulus of the sealing joint, that is, the stiffness of the pressing part and the fixing part is greater than the stiffness of the sealing joint. The sealing joint is shaped and limited from two opposite directions by the pressing part and the fixing part with greater stiffness, which can ensure the shape stability of the sealing joint, thereby effectively controlling the fluid-driven flexible actuator.

[0017] Furthermore, the flexible side wall includes a strain-uniformly distributed stacking structure that can be folded and / or stretched along the direction of the central axis of the cavity. 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. The strain-uniformly distributed stacking layers are enclosed by a single folding surface. A crease is formed at the connection between the folding surfaces of two adjacent strain-uniformly distributed stacking layers. The surface where the crease is located is a plane and perpendicular to the central axis of the cavity. The 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, α<60° or α>120°. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0019] Figure 1 A cross-sectional view of a partial structure of a fluid-driven robot module provided in an embodiment of the present application;

[0020] Figure 2 for Figure 1 The schematic diagram of the partial structure of the fluid pressure positive feedback sealing positioning structure of the fluid-driven robot module shown is after the sealing joint is hidden;

[0021] Figure 3 for Figure 1 The structure diagram of the sealing joint portion of the fluid pressure positive feedback sealing positioning structure of the fluid-driven robot module shown in FIG.

[0022] Figure 4 A cross-sectional view of a partial structure of another fluid-driven robot module provided in an embodiment of the present application;

[0023] Figure 5 for Figure 4 The schematic diagram of the partial structure of the fluid pressure positive feedback sealing positioning structure of the fluid-driven robot module shown is after the sealing joint is hidden;

[0024] Figure 6 for Figure 4 The structure diagram of the sealing joint of the fluid pressure positive feedback sealing positioning structure of the fluid-driven robot module shown is when no deformation occurs.

[0025] Among them, the reference numerals in the figures are:

[0026] 10. Flexible side wall; 11. Folding surface; 12. Crease;

[0027] 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;

[0028] 30. Pressed part; 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;

[0029] 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. Raised portion; 451. Ninth axial contact surface;

[0030] 50. Cavity;

[0031] 60. End cap;

[0032] 70. Annular body limited space;

[0033] 80. First annular opening;

[0034] 90. Second annular opening. DETAILED DESCRIPTION

[0035] The following describes in detail embodiments of the present application. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0036] In the description of this application, it should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0037] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0038] In this application, unless otherwise expressly specified or limited, terms such as "mounted," "connected," "connect," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components or interactions between two components. Those skilled in the art will understand the specific meanings of these terms in this application based on specific circumstances.

[0039] Example 1

[0040] Combine Figure 1 、 Figure 2 and Figure 3As shown, the 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. The fixing member 20 has a first contact surface 21 facing the cavity 50. The pressing member 30 is arranged in the cavity 50. The pressing member 30 The sealing joint 40 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. Abutment, the fourth contact surface 42 is sealed against the second contact surface 32, 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, 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, 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 channel 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.

[0041] 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.

[0042] When the fluid-driven flexible brake is in the initial state, affected by the assembly, the sealing joint 40 is squeezed by the pressing part 30 and the fixing part 20 to produce a certain prestrain, and due to the prestrain, it completely fits the shape of the annular body limiting space 70, so that the third contact surface 41 is sealed against the first contact surface 21, and the fourth contact surface 42 is sealed against the second contact surface 32, so as to cut off the channel between the cavity 50 and the external environment, thereby playing 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 will be received by the fluid pressure receiving surface 31 of the pressing piece 30 and transferred to the sealing joint 40 through the pressing piece 30. The setting of the second annular opening 90 provides space for the pressing piece 30 to move toward the fixing piece 20. Under the action of the fluid pressure, the pressing piece 30 moves toward the fixing piece 20 to reduce the height of the annular body limiting space 70, increase the deformation of the sealing joint 40, and thereby increase the pressure between the sealing joint 40 and the first contact surface 21 and the second contact surface 32, thereby enhancing the sealing effect. Moreover, the deformation of the sealing joint 40 will increase with the increase of the internal pressure of the cavity 50, showing a positive feedback relationship, and the increase in the deformation of the sealing joint 40 can make the first The contact surface 21 fits more closely with the third contact surface 41, and the second contact surface 32 fits more closely with the fourth contact surface 42, thereby realizing positive feedback between the sealing reliability and the fluid pressure in the cavity 50, effectively avoiding the problem of sealing failure due to excessive fluid pressure inside 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 increase the compression amount of the sealing joint 40 along the height direction of the annular body limiting space 70, so that the sealing joint 40 fits more closely with the first contact surface 21 and the second contact surface 32, further enhancing the sealing effect, which is beneficial to give full play to the bearing capacity of the flexible side wall 10 and the fixing part 20 itself so that the fluid-driven flexible actuator has greater power output capacity. In addition, the elastic modulus of the pressing part 30 and the fixing part 20 is greater than the elastic modulus of the sealing joint 40, that is, the stiffness of the pressing part 30 and the fixing part 20 is greater than the stiffness of the sealing joint 40. The pressing part 30 and the fixing part 20 with greater stiffness are used to shape and limit the sealing joint 40 from two opposite directions, which can ensure the shape stability of the sealing joint 40, thereby effectively controlling the fluid-driven flexible actuator.

[0043] It should be noted that the above-mentioned fluid can be gas or liquid.

[0044] Furthermore, the sealing joint 40 is integrally formed with the flexible side wall 10. By integrally forming the sealing joint 40 with the flexible side wall 10, it is possible to ensure that the sealing joint 40 and the flexible side wall 10 are reliably connected and not easily disconnected, thereby ensuring sealing reliability. In addition, the splicing gap between the sealing joint 40 and the flexible side wall 10 can be eliminated, and there is no need to fill the splicing gap between the sealing joint 40 and the flexible side wall 10 with sealant, sealing ring, etc. Specifically, the sealing joint 40 includes a second material with an elastic modulus of 10 to 1000 MPa and a positive Poisson's ratio. A positive Poisson's ratio material refers to a material in which the ratio of the transverse normal strain to the axial normal strain is positive when subjected to unidirectional tension or compression. In other words, when the material is stretched, it contracts laterally, and when the material is compressed, it expands laterally. In this embodiment, when the pressing part 30 and the fixing part 20 cooperate to squeeze the sealing joint 40 along the axial direction of the flexible side wall 10, that is, in the direction of the central axis of the cavity 50, the sealing joint 40 will produce axial compression along the direction of the central axis of the cavity 50, and at the same time there is a tendency to expand laterally in a direction perpendicular to the central axis of the cavity 50. However, since the width of the annular body limiting space 70 is fixed, the lateral expansion of the sealing joint 40 can be limited, which is conducive to increasing the axial compression amount of the sealing joint 40, so that the sealing joint 40 fits more closely with the first contact surface 21 and the second contact surface 32, further enhancing the sealing effect.

[0045] Furthermore, the sealing joint 40 includes an outer covering layer and an inner reinforcement layer arranged in the outer covering layer, the surface of the outer covering layer includes a third contact surface 41 and a fourth contact surface 42, the outer covering layer includes a second material, and the inner reinforcement layer includes a third material with an elastic modulus greater than 1GPa. The outer covering layer mainly plays a sealing role, and includes a second material with an elastic modulus of 10-1000MPa. When squeezed by the pressing part 30 and the fixing part 20, it can be deformed 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 part 20 and the second contact surface 32 of the pressing part 30, respectively, thereby playing a sealing role. The inner reinforcement layer is arranged inside the outer covering layer, and its elastic modulus is greater than the elastic modulus of the outer covering layer. Compared with the outer covering layer, it has higher rigidity and stronger ability to resist deformation, thereby improving the overall strength and structural stability of the sealing joint 40, which is beneficial to extending the service life of the sealing joint 40. The outer covering layer and the inner reinforcement layer can be integrally formed by secondary injection molding.

[0046] Furthermore, the sealing joint 40 is located at the edge of the press-fitting member 30 and extends along the edge contour of the press-fitting member 30 to form a closed loop structure arranged around the central axis of the cavity 50. The press-fitting member 30 has a connecting portion 33 for connecting to the fixing member 20. When the number of connecting portions 33 is greater than two, the distance between the connecting portion 33 and the edge contour of the press-fitting member 30 is less than the distance between the two connecting portions 33. When the press-fitting member 30 is connected to the fixing member 20 via the connecting portion 33, the press-fitting member 30 applies pressure toward the fixing member 20 to the sealing joint 40 assembled between the press-fitting member 30 and the fixing member 20, thereby cooperating with the fixing member 20 to squeeze the sealing joint 40. When the fluid pressure in the cavity 50 is equal to the external fluid pressure, the sealing joint 40 generates a certain pre-strain. When there is only one connection portion 33, the connection portion 33 can be positioned at the geometric center of the compression fitting 30 so that the distance between the connection portion 33 and each point on the edge contour line of the compression fitting 30 is as even as possible, thereby making the pre-strain of each portion of the sealing joint 40 in the direction around the central axis of the cavity 50 as even as possible, thereby improving the sealing reliability. When there are more than two connection portions 33, the distance between the connection portion 33 and the edge contour line of the compression fitting 30 is made smaller than the distance between any two connection portions 33, thereby reducing the distance between the connection portion 33 and the edge contour line of the compression fitting 30, i.e., bringing the connection portion 33 and the sealing joint 40 closer together. Therefore, when the compression fitting 30 and the fixing member 20 are connected via the connection portion 33, the extrusion force generated by the compression fitting 30 and the fixing member 20 can act more concentratedly on the sealing joint 40, thereby improving the sealing reliability.

[0047] Furthermore, the connection portion 33 may be a threaded hole, and a through hole 22 is provided at a position corresponding to the threaded hole in the fixing member 20. The fluid pressure positive feedback sealing positioning structure further comprises a threaded fastener, which passes through the through hole 22 and is threadedly connected to the threaded hole, thereby enabling the compression member 30 and the fixing member 20 to cooperate and clamp the sealing joint 40. More specifically, the threaded fastener comprises a head and a rod that are connected, the diameter of the head being larger than the diameter of the rod and the diameter of the through hole 22, the rod being provided with an external thread, and being threadedly connected to the threaded hole after passing through the through hole 22. When the fluid pressure in the cavity 50 is equal to the fluid pressure in the external environment, the head abuts against the side of the fixing member 20 facing away from the compression member 30, thereby enabling the compression member 30 and the fixing member 20 to cooperate and clamp the sealing joint 40. When the fluid pressure in the cavity 50 increases, the fluid pressure in the cavity 50 acts on the fluid pressure-bearing surface 31 of the compression fitting 30, causing the compression fitting 30 to move toward the fixing member 20 to reduce the distance between the compression fitting 30 and the fixing member 20, thereby increasing the deformation of the sealing joint 40. Since the rod of the threaded fastener is locked with the threaded hole of the compression fitting 30, the compression fitting 30 will drive the threaded fastener to move together, causing the head of the threaded fastener to separate from the compression fitting 30. When the fluid pressure in the cavity 50 decreases and becomes equal to the external fluid pressure again, the sealing joint 40 returns to its original state and pushes the compression fitting 30 away from the fixing member 20 to achieve reset, and the head of the threaded fastener again abuts against the fixing member 20.

[0048] Furthermore, the annular body limiting space 70 is annular cylindrical, and 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 press-fit part 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 part 20; the third axial contact surface 411 includes the third axial contact surface 411 and a third radial contact surface 412, the third axial contact surface 411 is sealedly abutted against 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 press-fit part 30, the third radial contact surface 412 is used to seal and abut against 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 sealedly abutted against 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 part 20, the fourth radial contact surface 422 is used to seal and abut against the second radial contact surface 322.

[0049] 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 sealed against the third axial contact surface 411, the second axial contact surface 321 is sealed against the fourth axial contact surface 421, the first radial contact surface 212 is sealed against the third radial contact surface 412, and the second radial contact surface 322 is sealed against the fourth radial contact surface 422, so that sealing can be achieved in both axial and radial directions to improve the reliability of sealing. 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 first axial contact surface 211 and the second axial contact surface 321 cooperate to limit the sealing joint 40 in the axial direction, and the first radial contact surface 212 and the second radial contact surface 322 cooperate to limit the sealing joint 40 in the radial direction, thereby ensuring the shape stability of the sealing joint 40 and effectively controlling the fluid-driven flexible actuator.

[0050] Further, the second radial contact surface 322 is a cylindrical surface with a uniform 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, where 1.2L1 < D1 < 2L1 and 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, where 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 undergo axial compression and radial expansion, that is, the distance between the third axial contact surface 411 and the fourth axial contact surface 421 decreases, and the distance between the third radial contact surface 412 and the fourth radial contact surface 422 increases, 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 and 1.05D2 < L2 < 1.2D2, space can be provided for the deformation of the sealing joint 40 during assembly, enabling the sealing joint 40 to generate a certain pre-deformation amount, ensuring the initial sealing effect, and at the same time avoiding direct contact between the fixing member 20 and the pressing member 30. By controlling 0.7D2 < D3 < D2, the structural and dimensional stability of the sealing joint 40 can be better maintained, avoiding local damage caused by excessive pressure and resulting in sealing failure.

[0051] 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.

[0052] Furthermore, the fixing member 20 also has a fifth axial contact surface 23, which is perpendicular to the first radial contact surface 212, connected to the side of the first radial contact surface 212 away from the first axial contact surface 211, and located on the side of the first radial contact surface 212 away from the central axis of the cavity 50; the pressing member 30 also has a fifth radial contact surface 34, which is perpendicular to the second axial contact surface 321, connected to the side of the second axial contact surface 321 away from the second radial contact surface 322, and located on the side of the second axial contact surface 321 away from the fixing member 20; the sealing joint 40 also has a sixth axial contact surface 4 3 and the 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 contact 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 contact with the fifth radial contact surface 34. By providing a fifth axial contact surface 23 on the fixing member 20, a fifth radial contact surface 34 on the compression member 30, and a sixth axial contact surface 43 and a sixth radial contact surface 44 on the sealing joint 40, the fifth axial contact surface 23 is in sealing contact with the sixth axial contact surface 43, and the fifth radial contact surface 34 is in sealing contact with the sixth radial contact surface 44. This further increases the contact area between the fixing member 20 and the sealing joint 40, and between the compression member 30 and the sealing joint 40, thereby improving sealing reliability. Specifically, when the fluid pressure within the cavity 50 is equal to the external ambient fluid pressure, due to the influence of assembly, the fifth axial contact surface 23 is already in sealing contact with the sixth axial contact surface 43, and the fifth radial contact surface 34 is already in sealing contact with the sixth radial contact surface 44.

[0053] Example 2

[0054] like Figure 1 As 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 positioning structure provided in the first embodiment.

[0055] By applying the fluid pressure positive feedback sealing 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 side wall 10 will be received by the fluid pressure receiving surface 31 of the pressing piece 30 and transferred to the sealing joint 40 through the pressing piece 30. The second annular opening 90 is set to provide space for the pressing piece 30 to move toward the fixing piece 20. Under the action of the fluid pressure, the pressing piece 30 moves toward the fixing piece 20 to reduce the height of the annular body limiting space 70, increase the deformation of the sealing joint 40, and thereby increase the pressure between the sealing joint 40 and the first contact surface 21 and the second contact surface 32, thereby achieving the effect of enhancing the sealing effect, and the deformation of the sealing joint 40 will increase with the increase of the internal pressure of the cavity 50, showing a positive feedback relationship, and the shape of the sealing joint 40 The increase in the variable can make the first contact surface 21 and the third contact surface 41 fit more closely, and the second contact surface 32 and the fourth contact surface 42 fit more closely, thereby realizing positive feedback between the sealing reliability and the fluid pressure in the cavity 50, and effectively avoiding the problem of sealing failure due to excessive fluid pressure inside 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 increase the compression amount of the sealing joint 40 along the height direction of the annular body limiting space 70, so that the sealing joint 40 fits more closely with the first contact surface 21 and the second contact surface 32, further enhancing the sealing effect, which is beneficial to give full play to the bearing capacity of the flexible side wall 10 and the fixing part 20 itself so that the fluid-driven flexible actuator has greater power output capacity. In addition, the elastic modulus of the pressing part 30 and the fixing part 20 is greater than the elastic modulus of the sealing joint 40, that is, the stiffness of the pressing part 30 and the fixing part 20 is greater than the stiffness of the sealing joint 40. The pressing part 30 and the fixing part 20 with greater stiffness are used to shape and limit the sealing joint 40 from two opposite directions, which can ensure the shape stability of the sealing joint 40, thereby effectively controlling the fluid-driven flexible actuator.

[0056] The outer contour 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 cylindrical, both axial ends of the flexible sidewall 10 have openings, and the fixing member 20 is disposed at one of the openings of the flexible sidewall 10. The fluid-driven flexible actuator further includes an end cap 60, which is disposed at the other opening of the flexible sidewall 10. The flexible sidewall 10, the fixing member 20, and the end cap 60 together enclose a deformable cavity 50.

[0057] 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 into 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.

[0058] The flexible sidewall 10 comprises a strain-uniformly distributed stacked structure that can fold and / or stretch along the central axis of the cavity 50. The strain-uniformly distributed stacked structure comprises at least two strain-uniformly distributed stacked layers stacked along the central axis of the cavity 50. The strain-uniformly distributed stacked layers are enclosed by a single folding surface 11. The connection between the folding surfaces 11 of two adjacent strain-uniformly distributed stacked layers forms a crease 12. The surface on which the crease 12 lies is planar and perpendicular to the central axis of the cavity 50. The folding surface 11 adjacent to the sealing joint 40 forms an angle α with a 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, where α is less than 60° or α is greater than 120°. During operation, when the pressure of the fluid in the cavity 50 increases, the flexible sidewall 10 can stretch along the central axis of the cavity 50, thereby increasing the space in the cavity 50. Conversely, when the pressure of the fluid in the cavity 50 decreases, the flexible sidewall 10 can fold along the central axis of the cavity 50, thereby decreasing the space in the cavity 50. By designing the surface of the fold 12 between the folding surfaces 11 of two adjacent uniformly strained stacked layers as a plane and perpendicular to the central axis of the cavity 50, the flexible sidewall 10 can be stably folded or expanded along the central axis of the cavity 50. By designing α < 60° or α > 120°, the structural stability of the flexible sidewall 10 is ensured, preventing the flexible sidewall 10 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.

[0059] Example 3

[0060] Combine Figure 4 、 Figure 5 and Figure 6As shown, this embodiment provides another fluid pressure positive feedback sealing positioning structure, which is different from the fluid pressure positive feedback sealing positioning structure provided in Example 1 in that: the pressing piece 30 also has a seventh axial contact surface 35, the seventh axial contact surface 35 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 when the assembly is completed and the pressure difference between the inside and outside of the cavity 50 is 0, the seventh axial contact surface 35 is spaced apart from the first axial contact surface 211 to provide space for the deformation of the sealing joint 40. The first axial contact surface 211 is partially 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 of the sealing joint 40 increases, and the gap between the seventh axial contact surface 35 and the first axial contact surface 211 decreases. When the deformation of the sealing 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 a rigid collision between the fixing part 20 and the pressing part 30.

[0061] Furthermore, the third axial contact surface 411 of the sealing joint 40 is partially raised to form a raised portion 45, which 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. The side of the raised 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 configured to sealably abut against the eighth axial contact surface 241 to enhance the sealing effect. When the fluid pressure within the cavity 50 is equal to the ambient fluid pressure, the eighth axial contact surface 241 and the ninth axial contact surface 451 may be in a sealed abutment state or separated. In the latter case, as the fluid pressure within the cavity 50 increases, the sealing joint 40 continuously deforms, and the ninth axial contact surface 451 gradually approaches the eighth axial contact surface 241. However, when the fluid pressure within the cavity 50 reaches a certain level, the ninth axial contact surface 451 seals against the eighth axial contact surface 241.

[0062] The rest of this embodiment is the same as that of the first embodiment. The features not explained in this embodiment are all based on the explanations of the first embodiment and will not be repeated here.

[0063] Example 4

[0064] like Figure 6As shown, the embodiment of the present application also provides a fluid-driven robot module, including a flexible side wall 10 and the fluid pressure positive feedback sealing positioning structure provided in the third embodiment.

[0065] By applying the fluid pressure positive feedback sealing positioning structure provided in Example 3, when the fluid pressure in the cavity 50 is increased, the fluid pressure along the axial direction of the flexible side wall 10 will be received by the fluid pressure receiving surface 31 of the pressing piece 30 and transferred to the sealing joint 40 through the pressing piece 30. The second annular opening 90 is set to provide space for the pressing piece 30 to move toward the fixing piece 20. Under the action of the fluid pressure, the pressing piece 30 moves toward the fixing piece 20 to reduce the height of the annular body limiting space 70, increase the deformation of the sealing joint 40, and thereby increase the pressure between the sealing joint 40 and the first contact surface 21 and the second contact surface 32, thereby achieving the effect of enhancing the sealing effect, and the deformation of the sealing joint 40 will increase with the increase of the internal pressure of the cavity 50, showing a positive feedback relationship, and the shape of the sealing joint 40 The increase in the variable can make the first contact surface 21 and the third contact surface 41 fit more closely, and the second contact surface 32 and the fourth contact surface 42 fit more closely, thereby realizing positive feedback between the sealing reliability and the fluid pressure in the cavity 50, and effectively avoiding the problem of sealing failure due to excessive fluid pressure inside 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 increase the compression amount of the sealing joint 40 along the height direction of the annular body limiting space 70, so that the sealing joint 40 fits more closely with the first contact surface 21 and the second contact surface 32, further enhancing the sealing effect, which is beneficial to give full play to the bearing capacity of the flexible side wall 10 and the fixing part 20 itself so that the fluid-driven flexible actuator has greater power output capacity. In addition, the elastic modulus of the pressing part 30 and the fixing part 20 is greater than the elastic modulus of the sealing joint 40, that is, the stiffness of the pressing part 30 and the fixing part 20 is greater than the stiffness of the sealing joint 40. The pressing part 30 and the fixing part 20 with greater stiffness are used to shape and limit the sealing joint 40 from two opposite directions, which can ensure the shape stability of the sealing joint 40, thereby effectively controlling the fluid-driven flexible actuator.

[0066] The outer contour 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 cylindrical, both axial ends of the flexible sidewall 10 have openings, and the fixing member 20 is disposed at one of the openings of the flexible sidewall 10. The fluid-driven flexible actuator further includes an end cap 60, which is disposed at the other opening of the flexible sidewall 10. The flexible sidewall 10, the fixing member 20, and the end cap 60 together enclose a deformable cavity 50.

[0067] 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 into 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.

[0068] The flexible sidewall 10 comprises a strain-uniformly distributed stacked structure that can fold and / or stretch along the central axis of the cavity 50. The strain-uniformly distributed stacked structure comprises at least two strain-uniformly distributed stacked layers stacked along the central axis of the cavity 50. The strain-uniformly distributed stacked layers are enclosed by a single folding surface 11. The connection between the folding surfaces 11 of two adjacent strain-uniformly distributed stacked layers forms a crease 12. The surface on which the crease 12 lies is planar and perpendicular to the central axis of the cavity 50. The folding surface 11 adjacent to the sealing joint 40 forms an angle α with a 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, where α is less than 60° or α is greater than 120°. During operation, when the pressure of the fluid in the cavity 50 increases, the flexible sidewall 10 can stretch along the central axis of the cavity 50, thereby increasing the space in the cavity 50. Conversely, when the pressure of the fluid in the cavity 50 decreases, the flexible sidewall 10 can fold along the central axis of the cavity 50, thereby decreasing the space in the cavity 50. By designing the surface of the fold 12 between the folding surfaces 11 of two adjacent uniformly strained stacked layers as a plane and perpendicular to the central axis of the cavity 50, the flexible sidewall 10 can be stably folded or expanded along the central axis of the cavity 50. By designing α < 60° or α > 120°, the structural stability of the flexible sidewall 10 is ensured, preventing the flexible sidewall 10 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.

[0069] It should be noted that the above is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application should be included in the scope of protection 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) enclose a deformable cavity (50), and the fixing member (20) has There is a first contact surface (21) arranged facing the cavity (50), the pressing piece (30) is arranged in the cavity (50), the pressing piece (30) has 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) and the fixing piece (20) are connected, 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, the fixing piece (20) and the pressing piece (30) include an elastic modulus greater than 50GPa 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) having 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 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) that 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 member (20) and the pressing member (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 bearing surface (31) to cause the pressing member (30) to move toward the fixing member (20) to reduce the height of the annular body limiting space, increase the deformation of the sealing joint (40), and thus increase the pressure between the sealing joint (40) and the first contact surface (21) and the second contact surface (32), thereby 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, characterized in that: The sealing joint portion (40) is integrally formed with the flexible side wall (10).

3. The fluid pressure positive feedback sealing and positioning structure according to claim 1, characterized in that: 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 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 sealing and positioning structure according to claim 1, characterized in that: The sealing joint portion (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 two of the connecting portions (33).

5. The fluid pressure positive feedback sealing and positioning structure according to claim 1, characterized in that: 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 abutment with the first axial contact surface (211), and the third radial contact surface (412) is in 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) that are perpendicularly connected. The fourth axial contact surface (421) is in sealing abutment with the second axial contact surface (321), and the fourth radial contact surface (422) is in sealing abutment with the second radial contact surface (322).

6. The fluid pressure positive feedback sealing and positioning structure according to claim 5, characterized in that: The second radial contact surface (322) is an equal-width cylindrical surface with a width of L1. The distance between the first radial contact surface (212) and the second radial contact surface (322) is L2; when the sealing joint portion (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 cylindrical surface; the second axial contact surface (321) is in the shape of a circular ring, an elliptical ring or a racetrack ring; 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) being perpendicular to the first radial contact surface (212), and the fifth axial contact surface (23) and the first axial contact surface (211) being connected to opposite sides of the first radial contact surface (212) respectively; The press-fitting component (30) further comprises a fifth radial contact surface (34), the fifth radial contact surface (34) being perpendicular to the second axial contact surface (321), the fifth radial contact surface (34) and the second radial contact surface (322) being connected to opposite sides of the second axial contact surface (321) respectively; The sealing joint (40) further comprises a sixth axial contact surface (43) and a sixth radial contact surface (44), wherein the sixth axial contact surface (43) is vertically connected to the third radial contact surface (412) and is in sealing contact with the fifth axial contact surface (23), and the sixth radial contact surface (44) is vertically connected to the fourth axial contact surface (421) and is in sealing contact with the fifth radial contact surface (34).

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

10. The fluid-driven robot module according to claim 9, characterized in that: 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), and 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), and the strain-uniformly distributed stacking layers are enclosed by a single folding surface (11), and a folding line (12) is formed at the connection between the folding surfaces (11) of two adjacent strain-uniformly distributed stacking layers, and the surface where the folding line (12) is located is a plane and is perpendicular to the central axis of the cavity (50), and the angle between the folding surface (11) adjacent to the sealing joint (40) and a 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, and α is less than 60° or α is greater than 120°.

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