A cable-driven rolling diaphragm transmission device

Abstract

This invention discloses a cable-driven rolling diaphragm transmission device, comprising a piston moving module, a cable transmission module, and a housing. The piston moving module and the cable transmission module are located inside the housing, with the cable transmission module in the middle and the piston moving module at both ends. The piston moving module includes a first piston, a first rolling diaphragm, a first shaft, a second piston, a second rolling diaphragm, and a second shaft. The cable transmission module includes a cable assembly, a first sliding body, a second sliding body, and a translation core, both located between the first and second sliding bodies. The housing includes a first outer piston cavity, a second outer piston cavity, a first inner piston cavity, a second inner piston cavity, and a housing plate. The first outer piston cavity and the first inner piston cavity are respectively fitted onto the first rolling diaphragm, and the second inner piston cavity and the second outer piston cavity are respectively fitted onto the second rolling diaphragm.

Description

Technical Field

[0001] This invention belongs to the field of mechanical transmission technology, specifically relating to a cable-driven rolling diaphragm transmission device. Background Technology

[0002] A rolling diaphragm is a flexible sealing structure, typically made of fiber-reinforced rubber, that can serve as a deformable wall for pressure vessels. Rolling diaphragms are used in medical or remotely operated robots. In medical applications, rolling diaphragm actuation is particularly suitable for MRI-safe robots, enabling surgery during real-time scanning by allowing for rolling diaphragm drives that are incompatible with MRI. The use of rolling diaphragm transmission provides smooth force transmission, improving patient comfort, and the output force can be adjusted to suit various patient needs.

[0003] The rolling diaphragm is enclosed by a cylindrical wall and surrounds the piston. Axial pressure primarily acts on the surface of the rolling diaphragm against the piston surface, with a smaller portion filling the diaphragm convolution. When the piston's reaction force is less than the axial pressure applied to the piston surface, the piston translates axially along the cylinder centerline, while the outer and inner diaphragm walls roll along the cylindrical shell and piston side, respectively. This motion generates only rolling friction, not sliding friction, reducing the overall inherent friction during piston actuation compared to O-ring pistons.

[0004] A diaphragm drive is formed when a diaphragm is used at both ends of a fixed volume of fluid. In a diaphragm drive, the positive translation of the diaphragm at one end causes an equal positive translation at the other end. However, the actuator must operate under positive pressure to avoid pulling the diaphragm off the housing or piston wall and causing blockage. This means that if there is only one diaphragm drive line, transmission can only be "push" from either end. One way to achieve bidirectional control is to apply preload to both ends of the drive, for example, by mounting springs on the pistons to maintain a baseline positive pressure on the fluid. However, the springs apply different forces depending on their displacement, resulting in variations in preload across the actuator's range of motion.

[0005] Due to the low friction of rolling diaphragms and the power density and stiffness of hydraulic transmissions, rolling diaphragm actuators have broad application prospects in medical and remote-controlled robotics. However, in some rolling diaphragm configurations, the stiffness supporting the pressure preload may be traded off from the bearing load, and the transmission setup can be challenging. Summary of the Invention

[0006] The purpose of this invention is to solve the above-mentioned problems and provide a cable-driven rolling diaphragm transmission device that can realize bidirectional movement and control of the rolling diaphragm, minimize gaps and friction, and realize displacement transmission of the same amount and direction.

[0007] To solve the above-mentioned technical problems, the technical solution of the present invention is: a cable-driven rolling diaphragm transmission device, comprising a piston moving module, a cable transmission module, and a housing, wherein the piston moving module and the cable transmission module are located inside the housing, the cable transmission module is located in the middle, and the piston moving module is located at both ends; the piston moving module includes a first piston, a first rolling diaphragm, a first shaft, a second piston, a second rolling diaphragm, and a second shaft, wherein the first piston, the first rolling diaphragm, and the first shaft are symmetrically arranged with respect to the second piston, the second rolling diaphragm, and the second shaft, respectively; the cable transmission module includes a cable assembly, a first sliding body, a second sliding body, and a translation core, wherein the first sliding body and the second sliding body are symmetrically arranged and connected by a cable assembly. The rods are connected, and the cable assembly and translation core are both located between the first sliding body and the second sliding body; the first piston is located inside the first rolling diaphragm and is connected to the first sliding body through the first shaft, and the second piston is located inside the second rolling diaphragm and is connected to the second sliding body through the second shaft; the outer shell includes a first outer piston cavity, a second outer piston cavity, a first inner piston cavity, a second inner piston cavity, and an outer shell plate, with the first inner piston cavity and the first outer piston cavity located side by side at one end of the outer shell plate, and the second inner piston cavity and the second outer piston cavity located side by side at the other end of the outer shell plate; the first outer piston cavity and the first inner piston cavity are respectively sleeved on the first rolling diaphragm, and the second inner piston cavity and the second outer piston cavity are respectively sleeved on the second rolling diaphragm.

[0008] Preferably, the cable assembly includes a first cable, a second cable, a third cable, and a fourth cable. A first sliding body and a second sliding body are symmetrically arranged. The first sliding body has a first nut and a second nut. The second sliding body has a first fixed end, a second fixed end, a third nut, and a fourth nut. The first fixed end and the second fixed end are both located on the same end face of the second sliding body, and the third nut and the fourth nut are located on the other end face of the second sliding body. One end of the first cable and the second cable are connected to the first fixed end of the third nut and the second fixed end of the fourth nut, respectively, and the other end wraps around the first sliding body and is fixed to the translation core. One end of the third cable and the second cable are connected to the fixed end of the first nut and the second fixed end of the second nut, respectively, and the other end wraps around the second sliding body and is fixed to the translation core.

[0009] Preferably, the first outer piston cavity has a first outlet and a first inlet for liquid outlet and inlet; the second outer piston cavity has a second outlet and a second inlet for liquid outlet and inlet.

[0010] Preferably, a notch is formed between the first outer piston cavity and the first inner piston cavity to fix the head of the first rolling diaphragm; a notch is formed between the second outer piston cavity and the second inner piston cavity to fix the head of the second rolling diaphragm.

[0011] Preferably, both the first and second rolling diaphragms are rotating structures with a "convex" shaped cross-section. The head of the first rolling diaphragm is embedded between the first outer piston cavity and the first inner piston cavity, and the tail is fitted onto the first piston. The head of the second rolling diaphragm is embedded between the first outer piston cavity and the first inner piston cavity, and the tail is fitted onto the second piston.

[0012] Preferably, the first piston and the first slider are connected by a first shaft; the second piston and the second slider are connected by a second shaft.

[0013] Preferably, the space between the first piston and the first sliding body is filled with liquid, and the space between the second piston and the second sliding body is filled with liquid; the interior of the first outer piston chamber is filled with gas or liquid, which flows in through the first inlet and flows out through the first outlet; the space between the second piston and the second sliding body is filled with liquid; the interior of the second outer piston chamber is filled with gas or liquid, which flows in through the second inlet and flows out through the second outlet.

[0014] Preferably, the first piston and the second piston are coaxially opposed, and there is a sealed chamber between the first rolling diaphragm and the second rolling diaphragm. The gas or liquid inside the first outer piston chamber and the second outer piston chamber are from the same source, that is, the preload pressure between the first sliding body and the second sliding body is balanced.

[0015] Preferably, the movement of the translation core includes an active transmission mode and a passive transmission mode. In the active transmission mode, by giving the translation core a rotation amount, the translation core drives the corresponding sliding body to move. Since there is a fixed liquid between the two sliding bodies, this movement pushes the other sliding body to the same side, that is, the two sliding bodies move in the same direction and in the same amount. In the passive transmission mode, a certain amount of liquid or gas is input through the first inlet or the second inlet, which pushes the first piston or the second piston to move, and thereby pushes the first sliding body or the second sliding body to move in the same direction. This movement drives the translation core to rotate in the forward or reverse direction.

[0016] The beneficial effects of this invention are:

[0017] 1. The cable-driven rolling diaphragm transmission device provided by the present invention can realize bidirectional movement and control of the rolling diaphragm through cable drive, and can achieve the mechanical characteristics of constant preload by connecting the same liquid source or air source.

[0018] 2. The cable-driven structure complements the advantages of rolling diaphragm transmission and minimizes backlash and friction. This transmission device enables displacement transmission in the same direction and magnitude. Combining two identical devices allows for long-distance displacement transmission in the same direction and magnitude. Attached Figure Description

[0019] Figure 1This is a schematic diagram of the principle of a cable-driven rolling diaphragm transmission device according to the present invention;

[0020] Figure 2 This is a schematic diagram of the working process of the present invention;

[0021] Figure 3 This is a schematic diagram illustrating the principle of this invention.

[0022] Explanation of reference numerals in the attached drawings: 1. First shaft; 2. First sliding body; 4. Second sliding body; 5. Outer shell plate; 6. Second inner piston chamber; 7. Second outer piston chamber; 8. Second rolling diaphragm; 9. Second piston; 10. Second shaft; 11. Translation core; 12. First piston; 13. First rolling diaphragm; 14. First outer piston chamber; 15. First inner piston chamber; 21. First nut; 22. Second nut; 31. First cable; 32. Second cable; 33. Third cable; 34. Fourth cable; 41. First fixed end; 44. Second fixed end; 42. Third nut; 43. Fourth nut; 72. Second outlet; 71. Second inlet; 141. First outlet; 142. First inlet. Detailed Implementation

[0023] The present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0024] like Figures 1 to 3As shown, the present invention provides a cable-driven rolling diaphragm transmission device, comprising a piston moving module, a cable transmission module, and a housing. The piston moving module and the cable transmission module are located within the housing, with the cable transmission module in the middle and the piston moving module at both ends. The piston moving module includes a first piston 12, a first rolling diaphragm 13, a first shaft 1, a second piston 9, a second rolling diaphragm 8, and a second shaft 10. The first piston 12, the first rolling diaphragm 13, and the first shaft 1 are symmetrically arranged with the second piston 9, the second rolling diaphragm 8, and the second shaft 10, respectively. The cable transmission module includes a cable assembly, a first sliding body 2, a second sliding body 4, and a translation core 11. The first sliding body 2 and the second sliding body 4 are symmetrically arranged and connected by a connecting rod. The cable assembly and the translation core 11 are both located between the first sliding body 2 and the second sliding body 4. The first piston 12 is located within the first rolling diaphragm 13 and is connected to the first sliding body 2 via the first shaft 1. The second piston 9 is located within the second rolling diaphragm 8 and is connected to the second sliding body 4 via the second shaft 10. In this embodiment, the outer shell is a hollow structure, comprising a first outer piston cavity 14, a second outer piston cavity 7, a first inner piston cavity 15, a second inner piston cavity 6, and an outer shell plate 5. The first inner piston cavity 15 and the first outer piston cavity 14 are located side by side at one end of the outer shell plate 5, and the second inner piston cavity 6 and the second outer piston cavity 7 are located side by side at the other end of the outer shell plate 5. The first outer piston cavity 14 and the first inner piston cavity 15 are respectively sleeved on the first rolling diaphragm 13, and the second inner piston cavity 6 and the second outer piston cavity 7 are respectively sleeved on the second rolling diaphragm 8.

[0025] The cable assembly includes a first cable 31, a second cable 32, a third cable 33, and a fourth cable 34. The first sliding body 2 and the second sliding body 4 are arranged symmetrically. The first sliding body 2 is provided with a first nut 21 and a second nut 22. The second sliding body 4 is provided with a first fixed end 41, a second fixed end 44, a third nut 42, and a fourth nut 43. The first fixed end 41 and the second fixed end 44 are both located on the same end face of the second sliding body 4, and the third nut 42 and the fourth nut 43 are located on the other end face of the second sliding body 4.

[0026] In this embodiment, the first nut 21, the second nut 22, the third nut 42, and the fourth nut 43 are parallel to each other and located at the same height. Both the first sliding body 2 and the second sliding body 4 are block structures. The first nut 21 and the second nut 22 are both inserted through the top of the first sliding body 2, and the third nut 42 and the fourth nut 43 are both inserted through the top of the second sliding body 4. Each of the first nut 21, the second nut 22, the third nut 42, and the fourth nut 43 has a fixed end, which is a cylindrical structure and is fixedly connected to the corresponding cable. One end of the first cable 31 and the second cable 32 is connected to the first fixed end 41 at the tail of the third nut 43 and the second fixed end 44 at the tail of the fourth nut 44, and the other end wraps around the first sliding body 2 and is fixed to the translation core 11. One end of the third cable 33 and the second cable 34 is connected to the fixed end at the tail of the first nut 21 and the fixed end at the tail of the second nut 22, and the other end wraps around the second sliding body 4 and is fixed to the translation core 11.

[0027] The first outer piston chamber 14 has a first outlet 141 and a first inlet 142 for liquid outlet and inlet, respectively. The second outer piston chamber 7 has a second outlet 72 and a second inlet 71 for liquid outlet and inlet, respectively.

[0028] In this embodiment, both the first outer piston cavity 14 and the second outer piston cavity 7 are hollow rotating structures and are symmetrically arranged. The cross-sections of both the first outer piston cavity 14 and the second outer piston cavity 7 are stepped structures. The first outlet 141 and the second outlet 142 are perpendicular to each other. The first outlet 141 is located along the axis of the first outer piston cavity 14, and the axis of the second outlet 142 is perpendicular to the axis of the first outer piston cavity 14. The structures of the second outlet 72 and the second inlet 71 are the same as those of the first outlet 141 and the first inlet 142, respectively.

[0029] A notch is formed between the first outer piston chamber 14 and the first inner piston chamber 15 to fix the head of the first rolling diaphragm 13. A notch is formed between the second outer piston chamber 7 and the second inner piston chamber 6 to fix the head of the second rolling diaphragm 8. In this embodiment, the notch between the first outer piston chamber 14 and the first inner piston chamber 15 is a groove structure, and the end of the first rolling diaphragm 13 is located within the notch. The notch between the second outer piston chamber 7 and the second inner piston chamber 6 is a groove structure, and the top of the second rolling diaphragm 8 is located within the notch.

[0030] Both the first rolling diaphragm 13 and the second rolling diaphragm 8 are rotating structures with a convex cross-section. The head of the first rolling diaphragm 13 is embedded between the first outer piston cavity 14 and the first inner piston cavity 15, and the tail is fitted onto the first piston 12. The head of the second rolling diaphragm 8 is embedded between the first outer piston cavity 14 and the first inner piston cavity 15, and the tail is fitted onto the second piston 9.

[0031] The first piston 12 is connected to the first sliding body 2 via the first shaft 1. The second piston 9 is connected to the second sliding body 4 via the second shaft 10.

[0032] The space between the first piston 12 and the first sliding body 2 is filled with liquid, and the space between the second piston 9 and the second sliding body 4 is also filled with liquid. The interior of the first outer piston chamber 14 is filled with gas or liquid, which flows in through the first inlet 142 and flows out through the first outlet 141. The space between the second piston 9 and the second sliding body 4 is filled with liquid, and the interior of the second outer piston chamber 7 is filled with gas or liquid, which flows in through the second inlet 71 and flows out through the second outlet 72.

[0033] The first piston 12 and the second piston 9 are coaxially opposite each other. The first rolling diaphragm 13 and the second rolling diaphragm 8 form a sealed chamber. The gas or liquid inside the first outer piston chamber 14 and the second outer piston chamber 7 are from the same source. That is, the pre-tightening pressure between the first sliding body 2 and the second sliding body 4 is balanced.

[0034] The movement of the translation core 11 includes an active transmission mode and a passive transmission mode. In the active transmission mode, by giving the translation core 11 a certain amount of rotation, the translation core 11 drives the corresponding sliding body to move. Since there is a fixed liquid between the two sliding bodies, this movement pushes the other sliding body to the same side, that is, the two sliding bodies move in the same direction and by the same amount. In the passive transmission mode, a certain amount of liquid or gas is input through the first inlet 142 or the second inlet 72, which pushes the first piston 12 or the second piston 9 to move, thereby pushing the first sliding body 2 or the second sliding body 4 to move in the same direction. This movement drives the translation core 11 to rotate in the forward or reverse direction.

[0035] like Figure 3 The diagram illustrates the connection relationships in the specific application of this invention. It consists of two identical cable-driven rolling diaphragm devices, a water pump, a water tank, a solenoid valve, a potentiometer, compressed air, and a pressure regulator. The water pump, water tank, solenoid valve, potentiometer, compressed air, and pressure regulator can be readily available and technologically mature equipment. A set of cable-driven rolling diaphragm devices is installed at both the input and output points. The two devices are connected by a hydraulic line, which is considered an incompressible connection between the devices, and can be thought of as a solid rod connecting the two devices, with the water volume being the length of the rod. Conversely, the lines are connected to the same air source to provide preload pressure. High preload pressure helps dissolve excess air into the water, thereby achieving a system with high rigidity and high responsiveness.

[0036] The water pump is connected to the water tank. The water pump and water tank are respectively connected to cable-driven rolling diaphragm devices at the input and output points via solenoid valves. Potentiometers are connected to each cable-driven rolling diaphragm device. A pressure sensor is installed on the pipeline connecting the water pump and the solenoid valve. The cable-driven rolling diaphragm devices at the input and output points are respectively connected to a pressure regulator, which is connected to compressed air. In this embodiment, the compressed air is provided by existing air source equipment or air compression equipment.

[0037] The amount of water in the hydraulic lines determines the phase offset between the input and output shafts. This phase offset can be adjusted by adding or removing water from the lines. Water in the hydraulic lines is drawn from a tank by a water pump, and the water volume is adjusted by regulating the input or output hydraulic lines via a solenoid valve and by adjusting the water pressure in the lines via a pressure sensor.

[0038] Figure 3 The system shown comprises a cable-driven rolling diaphragm transmission device, a water pump, a water tank, a solenoid valve, a potentiometer, compressed air, and a pressure regulator. It enables remote reproduction of input quantities with the same displacement and direction. The working process is as follows: An input motor and a potentiometer are installed at the translation core of the input device, and a potentiometer is installed at the translation core of the output device. When the input passes through a given rotation of the translation core, i.e., the input device operates in active transmission mode, the two sliding bodies of the input device move in the same direction and with the same amount of rotation. The liquid between the two devices is considered an incompressible rod; this displacement is added to the left side of the output device. When the output device operates in passive transmission mode, this movement drives the translation core to rotate in the forward or reverse direction, and the output rotation is measured by the potentiometer.

[0039] Those skilled in the art will recognize that the embodiments described herein are intended to help the reader understand the principles of the invention, and should be understood that the scope of protection of the invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific modifications and combinations based on the technical teachings disclosed in this invention without departing from the spirit of the invention, and these modifications and combinations are still within the scope of protection of this invention.

Claims

1. A cable-driven rolling diaphragm transmission device, characterized in that: The device includes a piston moving module, a cable drive module, and a housing. The piston moving module and the cable drive module are located inside the housing, with the cable drive module in the middle and the piston moving module at both ends. The piston moving module includes a first piston (12), a first rolling diaphragm (13), a first shaft (1), a second piston (9), a second rolling diaphragm (8), and a second shaft (10). The first piston (12), the first rolling diaphragm (13), and the first shaft (1) are symmetrically arranged with the second piston (9), the second rolling diaphragm (8), and the second shaft (10), respectively. The cable drive module includes a cable assembly, a first sliding body (2), a second sliding body (4), and a translation core (11). The first sliding body (2) and the second sliding body (4) are symmetrically arranged and connected by a connecting rod. The cable assembly and the translation core (11) are both located on the first sliding body (2) and the second sliding body (4). Between; the first piston (12) is located inside the first rolling diaphragm (13) and connected to the first sliding body (2) through the first shaft (1), the second piston (9) is located inside the second rolling diaphragm (8) and connected to the second sliding body (4) through the second shaft (10); the outer shell includes a first outer piston cavity (14), a second outer piston cavity (7), a first inner piston cavity (15), a second inner piston cavity (6) and an outer shell plate (5), the first inner piston cavity (15) and the first outer piston cavity (14) are located side by side at the end of the outer shell plate (5), the second inner piston cavity (6) and the second outer piston cavity (7) are located side by side at the other end of the outer shell plate (5); the first outer piston cavity (14) and the first inner piston cavity (15) are respectively sleeved on the first rolling diaphragm (13), the second inner piston cavity (6) and the second outer piston cavity (7) are respectively sleeved on the second rolling diaphragm (8).

2. The cable-driven rolling diaphragm transmission device according to claim 1, characterized in that: The cable assembly includes a first cable (31), a second cable (32), a third cable (33), and a fourth cable (34). The first sliding body (2) and the second sliding body (4) are symmetrically arranged. The first sliding body (2) is provided with a first nut (21) and a second nut (22). The second sliding body (4) is provided with a first fixed end (41), a second fixed end (44), a third nut (42), and a fourth nut (43). The first fixed end (41) and the second fixed end (44) are both located on the same end face of the second sliding body (4). The third nut (42) and the fourth nut... (43) is located on the other end face of the second sliding body (4); one end of the first cable (31) and the second cable (32) are connected to the first fixed end (41) of the tail of the third nut (42) and the second fixed end (44) of the tail of the fourth nut (43), and the other end is wrapped around the first sliding body (2) and fixed on the translation core (11); one end of the third cable (33) and the fourth cable (34) are connected to the fixed end of the tail of the first nut (21) and the fixed end of the tail of the second nut (22), and the other end is wrapped around the second sliding body (4) and fixed on the translation core (11).

3. The cable-driven rolling diaphragm transmission device according to claim 1, characterized in that: The first outer piston chamber (14) has a first outlet (141) and a first inlet (142) for liquid outlet and inlet; the second outer piston chamber (7) has a second outlet (72) and a second inlet (71) for liquid outlet and inlet.

4. The cable-driven rolling diaphragm transmission device according to claim 1, characterized in that: A notch is provided between the first outer piston chamber (14) and the first inner piston chamber (15) for fixing the head of the first rolling diaphragm (13); a notch is provided between the second outer piston chamber (7) and the second inner piston chamber (6) for fixing the head of the second rolling diaphragm (8).

5. The cable-driven rolling diaphragm transmission device according to claim 1, characterized in that: The first rolling diaphragm (13) and the second rolling diaphragm (8) are both rotating structures with convex cross-sections. The head of the first rolling diaphragm (13) is embedded between the first outer piston cavity (14) and the first inner piston cavity (15), and the tail is fitted onto the first piston (12). The head of the second rolling diaphragm (8) is embedded between the first outer piston cavity (14) and the first inner piston cavity (15), and the tail is fitted onto the second piston (9).

6. The cable-driven rolling diaphragm transmission device according to claim 1, characterized in that: The first piston (12) is connected to the first sliding body (2) via a first shaft (1); the second piston (9) is connected to the second sliding body (4) via a second shaft (10).

7. The cable-driven rolling diaphragm transmission device according to claim 3, characterized in that: The space between the first piston (12) and the first sliding body (2) is filled with liquid, and the space between the second piston (9) and the second sliding body (4) is filled with liquid; the interior of the first outer piston chamber (14) is filled with gas or liquid, and the gas or liquid flows in through the first inlet (142) and flows out through the first outlet (141); the space between the second piston (9) and the second sliding body (4) is filled with liquid; the interior of the second outer piston chamber (7) is filled with gas or liquid, and the gas or liquid flows in through the second inlet (71) and flows out through the second outlet (72).

8. The cable-driven rolling diaphragm transmission device according to claim 1, characterized in that: The first piston (12) and the second piston (9) are coaxially opposed. The first rolling diaphragm (13) and the second rolling diaphragm (8) are a sealed chamber. The gas or liquid inside the first outer piston chamber (14) and the second outer piston chamber (7) are from the same source. That is, the pre-tightening pressure between the first sliding body (2) and the second sliding body (4) is balanced.

9. A cable-driven rolling diaphragm transmission device according to claim 3, characterized in that: The movement of the translation core (11) includes an active transmission mode and a passive transmission mode. In the active transmission mode, by giving the translation core (11) a rotation amount, the translation core (11) drives the corresponding sliding body to move. Since there is a fixed liquid between the two sliding bodies, this movement pushes the other sliding body to the same side, that is, the two sliding bodies move in the same direction and in the same amount. In the passive transmission mode, a certain amount of liquid or gas is input through the first inlet (142) or the second inlet (71) to push the first piston (12) or the second piston (9) to move, and thereby push the first sliding body (2) or the second sliding body (4) to move in the same direction. This movement drives the translation core (11) to rotate in the forward or reverse direction.

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