Magnetorheological clutch applied to passive ankle exoskeleton

Abstract

The application aims to provide a magneto-rheological clutch and a passive ankle exoskeleton applying the same, which comprises an upper cover plate, a lower cover plate, a shaft, an upper sealing end cover, a lower sealing end cover, an upper tab disc, a lower tab disc, a clock spring, a wire reel, a clutch disc, a magneto-rheological shell, a magneto-rheological brush, a pin key and a magnetic shielding sheet. The clutch uses a magnetic fluid damping device as a braking element, adjusts the magnetic field of a permanent magnet according to the human body movement, changes the properties of the magneto-rheological fluid, and realizes the clutching effect. The magneto-rheological clutch and the passive ankle exoskeleton applying the same do not need friction to fix, and solve the problem of excessive friction of the exoskeleton on the user's skin.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of human exoskeleton, in particular to a magnetic rheological clutch and passive ankle exoskeleton using the same. BACKGROUND

[0002] At present, passive ankle exoskeletons are basically quasi-passive lower limb exoskeletons. The support torque is provided by passive elements, and the support is engaged or separated by small actuators, thereby forming a quasi-passive device. Through passive support, the exoskeleton can be engaged or separated, and the user can achieve inconspicuous movement in tasks without assistance. Among them, the clutch is a key component, and the existing clutches include ratchet pawl clutches and electromagnetic device clutches.

[0003] Due to the high walking frequency of the human body, the traditional ratchet pawl clutch is prone to noise and wear during repeated operation, and is more prone to problems such as misalignment and jamming under the condition of long working time and insufficient lubrication. In active exoskeletons, electromagnetic devices are used as clutches, which require frequent on-off of electromagnets, and the electromagnets generate significant heat. In addition, the required magnetic force is large, the current requirement is high, and the human body needs to carry a power source. SUMMARY

[0004] The present application aims to provide a magnetic rheological clutch and passive ankle exoskeleton using the same, which uses a magnetic fluid damping device as a braking element, adjusts the magnetic field of the permanent magnet according to the human body's own movement, thereby changing the properties of the magnetic rheological fluid, and achieving the clutch effect.

[0005] The magnetic rheological clutch comprises an upper cover plate, a lower cover plate, a shaft, an upper sealing end cover, a lower sealing end cover, an upper pawl disc, a lower pawl disc, a clock spring, a wire reel, a clutch disc, a magnetic rheological shell, a magnetic rheological brush, a pin key, and a magnetic shielding sheet.

[0006] The two ends of the shaft are respectively connected to the centers of the upper cover plate and the lower cover plate, and the shaft near the opposite faces of the upper cover plate and the lower cover plate is respectively sleeved with the upper pawl disc and the lower pawl disc, which can rotate relative to the shaft, the upper cover plate and the lower cover plate; the shaft near the opposite faces of the upper pawl disc and the lower pawl disc is sleeved with the upper sealing end cover and the lower sealing end cover, and the connection between the upper sealing end cover and the lower sealing end cover and the shaft is sealed, and the shaft can rotate relative to the upper sealing end cover and the lower sealing end cover.

[0007] A group of clock springs are arranged on the upper cover plate and the lower cover plate, one end of each clock spring is fixedly connected to the upper cover plate and the lower cover plate, and the other end is fixedly connected to the upper pawl disc or the lower pawl disc.

[0008] The upper and lower dial plates are provided with a clutch disc, and the outer surface of the clutch disc is fixedly sleeved with a wire disc; the center of the clutch disc is fixedly installed with a magnetorheological shell, and the clutch disc, the wire disc and the magnetorheological shell can rotate relative to the upper and lower dial plates; the shaft passes through the hole in the center of the upper and lower end surfaces of the magnetorheological shell, and the hole is sealed by the upper and lower sealing end covers; the shaft can rotate relative to the upper and lower sealing end covers; the magnetorheological brush is fixedly installed on the shaft and located in the magnetorheological shell; and the magnetorheological shell is filled with magnetorheological fluid.

[0009] The side surface of the clutch disc is provided with a plurality of groups of inclined through grooves I, and the side surfaces of the upper and lower dial plates are respectively provided with inclined through grooves II corresponding to the inclined through grooves I; the pin keys are installed in the inclined through grooves I, and the two ends of the pin keys pass through the corresponding inclined through grooves II on the upper and lower dial plates; and one group of magnetic shielding plates is respectively installed on the two ends of the pin keys.

[0010] The side surface of the clutch disc is provided with a plurality of groups of inclined through grooves I, and the side surfaces of the upper and lower dial plates are respectively provided with inclined through grooves II corresponding to the inclined through grooves I; the pin keys are installed in the inclined through grooves I, and the two ends of the pin keys pass through the corresponding inclined through grooves II on the upper and lower dial plates; and one group of magnetic shielding plates is respectively installed on the two ends of the pin keys.

[0011] The upper and lower cover plates are connected through a plurality of groups of support columns, and each group of support columns is arranged on the outer side of the wire disc.

[0012] The inclination angles of the groups of inclined through grooves I on the side surface of the clutch disc are consistent.

[0013] The permanent magnet is an axial magnetization type cylindrical permanent magnet.

[0014] The two ends of the shaft are square rods, the upper and lower cover plates are correspondingly provided with square holes, and the square rods at the two ends of the shaft are respectively inserted into the square holes through clearance fit.

[0015] The opposite surfaces of the upper and lower cover plates are respectively provided with annular guide grooves in the center, and the upper ends of the upper and lower sealing end covers are correspondingly provided with sleeves; the upper and lower sealing end covers cannot move radially through the cooperation of the annular guide grooves and the sleeves.

[0016] The opposite surfaces of the upper and lower cover plates are also provided with support rings, and the support rings are arranged outside the annular guide grooves and are used for supporting the upper and lower dial plates.

[0017] The opposite surfaces of the upper and lower cover plates are also provided with a plurality of groups of support guide rings arranged at intervals, and the support guide rings are arranged between the support rings and the annular guide grooves and are used for supporting and guiding the sliding of the magnetic shielding plates.

[0018] The opening in the center of the upper and lower end faces of the magnetic flow body is provided with a bearing, and the inner ring of the bearing is fixedly connected with the shaft.

[0019] The application further provides a passive ankle exoskeleton applying the magnetic flow clutch, and further comprising a rope I and a rope II; the magnetic flow clutch of the passive ankle exoskeleton is installed at the back of a leg guard of a human calf; the upper end of the rope I is connected with a wire reel away from the leg of the human being, and the lower end is connected with the rear end of a load ring of the foot of the human being; the rope II is connected with the wire reel close to the leg of the human being, and the lower end is connected with the front end of the load ring of the foot of the human being.

[0020] The passive ankle exoskeleton of the application can adopt the prior art except the magnetic flow clutch, for example, the utility model patent applied by the inventor: a passive ankle exoskeleton for reducing exercise metabolism, 202223379307.6. The magnetic flow clutch of the application can be driven by a rope or directly rigidly driven at a joint.

[0021] The application designs a novel magnetic flow clutch, uses the combination of a magnetic flow fluid, a permanent magnet and a magnetic shielding sheet, and solves the problems of noise and misalignment jamming of a traditional clutch by using the change of the magnetic flow fluid under the conditions of having and not having a magnetic field.

[0022] The application optimizes a driving mode, uses a permanent magnet and a magnetic flow fluid to work, makes the clutching process more smooth, does not need an additional energy source, and only uses the human body itself to drive. Moreover, the clutch is rigidly connected with a binding structure, the braking mode is determined by a movement angle, the reaction is more rapid, usually in the order of milliseconds, the hysteresis is reduced, and the clutching start-stop of a higher frequency is supported. The binding mechanism is improved on the basis of the existing binding mechanism, rigid-flexible coupling is performed, the exoskeleton no longer needs friction to be fixed, and the problem of excessive friction of the exoskeleton on the skin of a user is solved. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 It is a front view of the magnetic flow clutch of embodiment 1;

[0024] Figure 2 It is a sectional view of the magnetic flow clutch of embodiment 1;

[0025] Figure 3 It is an explosion view of the magnetic flow clutch of embodiment 1;

[0026] Figure 4 It is an F-F sectional view of the magnetic flow clutch of embodiments 1 and 2 in an initial state with the upper and lower cover plates removed;

[0027] Figure 5 It is an F-F sectional view of the magnetic flow clutch of embodiments 1 and 2 in a locked state with the upper and lower cover plates removed;

[0028] Figure 6 This is a diagram showing the power storage state of the passive ankle exoskeleton in Example 2;

[0029] Figure 7 This is a diagram showing the reset state of the passive ankle exoskeleton clutch in Example 2;

[0030] The numbers and names in the diagram are as follows:

[0031] 1-Upper cover plate, 2-Lower cover plate, 3-Shaft, 4-Upper sealing end cover, 5-Lower sealing end cover, 6-Upper paddle plate, 7-Lower paddle plate, 8-Curling spring, 9-Spindle, 10-Clutch disc, 11-Magnetorheological housing, 12-Magnetorheological brush, 13-Slanted through groove I, 14-Slanted through groove II, 15-Permanent magnet groove, 16-Permanent magnet, 17-Support column, 18-Square hole, 19-Annular guide groove, 20-Collar ring, 21-Support ring, 22-Bearing, 23-Pin key, 24-Magnetic shielding plate, 25-Support guide ring. Detailed Implementation

[0032] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. Example 1

[0033] like Figures 1-5 As shown, the magnetorheological clutch applied to the passive ankle exoskeleton includes an upper cover plate 1, a lower cover plate 2, a shaft 3, an upper sealing end cover 4, a lower sealing end cover 5, an upper paddle plate 6, a lower paddle plate 7, a spring 8, a coil 9, a clutch disc 10, a magnetorheological housing 11, a magnetorheological brush 12, a key pin 23, and a magnetic shielding plate 24.

[0034] The upper cover plate 1 and the lower cover plate 2 are connected by multiple sets of support columns 17, and each set of support columns 17 is located on the outside of the coil 9.

[0035] The shaft 3 has square rods at both ends. The upper cover plate 1 and the lower cover plate 2 are respectively provided with square holes 18. The square rods at both ends of the shaft 3 are respectively inserted into the square holes 18 through clearance fit. The shaft 3 near the opposite surfaces of the upper cover plate 1 and the lower cover plate 2 is respectively fitted with an upper paddle disc 6 and a lower paddle disc 7. The opposite surfaces of the upper cover plate 1 and the lower cover plate 2 are also provided with a support ring 21. The support ring 21 is located outside the annular guide groove 19 and is used to support the upper paddle disc 6 or the lower paddle disc 7.

[0036] The upper dial disc 6 and the lower dial disc 7 can rotate relative to the shaft 3, the upper cover plate 1 and the lower cover plate 2; the shaft 3 is sleeved with the upper sealing end cover 4 and the lower sealing end cover 5 at the opposite faces of the upper dial disc 6 and the lower dial disc 7, the upper sealing end cover 4 and the lower sealing end cover 5 are sealed at the connection with the shaft 3, and the shaft 3 can rotate relative to the upper sealing end cover 4 and the lower sealing end cover 5; the opposite faces of the upper cover plate 1 and the lower cover plate 2 are respectively provided with annular guide grooves 19 in the center, and the upper ends of the upper sealing end cover 4 and the lower sealing end cover 5 are respectively provided with sleeves 20, so that the upper sealing end cover 4 and the lower sealing end cover 5 cannot move radially through cooperation of the annular guide grooves 19 and the sleeves 20;

[0037] The upper cover plate 1 and the lower cover plate 2 are respectively provided with a group of clockwork springs 8, one end of the clockwork spring 8 is fixedly connected with the upper cover plate 1 and the lower cover plate 2, and the other end is fixedly connected with the upper dial disc 6 or the lower dial disc 7;

[0038] The upper dial disc 6 and the lower dial disc 7 are provided with a clutch disc 10 therebetween, and the outer circular face of the clutch disc 10 is fixedly sleeved with a wire disc 9; the clutch disc 10 is fixedly installed with a magneto-rheological shell 11 in the center, the clutch disc 10, the wire disc 9 and the magneto-rheological shell 11 can rotate relative to the upper dial disc 6 and the lower dial disc 7, the shaft 3 passes through the holes in the centers of the upper and lower end faces of the magneto-rheological shell 11, the holes are sealed by the upper sealing end cover 4 or the lower sealing end cover 5, and the shaft 3 can rotate relative to the upper sealing end cover 4 and the lower sealing end cover 5; a magneto-rheological brush 12 is fixedly installed on the shaft 3 and located in the magneto-rheological shell 11, the magneto-rheological shell 11 is filled with magneto-rheological fluid; the holes in the centers of the upper and lower end faces of the magneto-rheological shell 11 are provided with bearings 22, and the inner rings of the bearings 22 are fixedly connected with the shaft 3.

[0039] The side face of the clutch disc 10 is provided with a plurality of groups of inclined through grooves I 13, the inclination angles of the groups of inclined through grooves I 13 on the side face of the clutch disc 10 are consistent; the side faces of the upper dial disc 6 and the lower dial disc 7 are respectively provided with inclined through grooves II 14 corresponding to the inclined through grooves I 13 one by one; a pin key 23 is installed in the inclined through grooves I 13, and the two ends of the pin key 23 pass through the corresponding inclined through grooves II 14 on the upper dial disc 6 and the lower dial disc 7, and a group of magnetic shielding pieces 24 are respectively installed on the two ends of the pin key 23; a plurality of groups of support guide rings 25 are further provided on the opposite faces of the upper cover plate 1 and the lower cover plate 2, the support guide rings 25 are arranged between the support ring 21 and the annular guide groove 19, and the support guide rings 25 are used for supporting and guiding the sliding of the magnetic shielding pieces 24;

[0040] The side of the clutch disc 10 is provided with a group of permanent magnet grooves 15 on one side of each inclined through groove I 13 near the center of the clutch disc 10, and permanent magnets 16 are installed in the permanent magnet grooves 15; the pin key 23 can slide along the inclined through groove I 13 and the inclined through groove II 14, so that the magnetic shielding sheet 24 covers or opens the two ends of the permanent magnet groove 15; the permanent magnet 16 is an axial magnetization type cylindrical permanent magnet.

[0041] The clutch disc 10 and the magnetic shielding sheet 24 are made of 20# steel.

[0042] The working principle of the clutch in the embodiment is as follows:

[0043] As shown in Figure 4 , the magnetic shielding sheet 24 covers the two ends of the permanent magnet 16 in the initial state of the magneto-rheological clutch, greatly reducing the magnetic field strength through the magneto-rheological fluid. At this time, the magneto-rheological fluid in the magneto-rheological fluid shell 11 is no different from general fluid, and the magneto-rheological fluid shell 11 and the magneto-rheological fluid brush 12 can rotate relative to each other without obstruction. At this time, the wire disc 9, the clutch disc 10, the pin key 23, the permanent magnet 16, the magneto-rheological fluid shell 11, and the magnetic shielding sheet 24 rotate coaxially. The shaft 3, the magneto-rheological fluid brush 12, the upper cover plate 1, and the lower cover plate 2 rotate coaxially; the upper sealing end cover 4, the lower sealing end cover 5, the upper paddle disc 6, and the lower paddle disc 7 rotate coaxially.

[0044] As shown in Figure 5 , the magnetic shielding sheet 24 does not cover the permanent magnet 16 in the locked state of the magneto-rheological clutch. When the wire disc 9 starts to rotate clockwise, the upper cover plate 1 and the lower cover plate 2 do not move, and the upper paddle disc 6 and the lower paddle disc 7 remain stationary under the action of the clockwork spring 8. The pin key 23 and the magnetic shielding sheet 24 perform vortex displacement under the guidance and limiting action of the inclined through groove I 13 and the inclined through groove II 14 of the clutch disc 10, the upper paddle disc 6, and the lower paddle disc 7. At this time, the magnetic field strength through the magneto-rheological fluid is greatly enhanced, the properties of the magneto-rheological fluid change, and the viscosity of the magneto-rheological fluid is greatly enhanced, which prevents the relative rotation of the magneto-rheological fluid shell 11 and the magneto-rheological fluid brush 12. At this time, the magneto-rheological clutch is locked and in a closed state. Embodiment 2

[0045] As shown in Figure 6 and Figure 7 , the embodiment provides a passive ankle exoskeleton, which applies the magneto-rheological clutch of the passive ankle exoskeleton of embodiment 1, and further includes a rope I 41 and a rope II 42; the magneto-rheological clutch of the passive ankle exoskeleton is installed at the back of the leg guard 43 of the human calf; the upper end of the rope I 41 is connected to one side of the wire disc 9 away from the human leg, and the lower end is connected to the rear end of the load ring 44 of the human foot; the rope II 42 is connected to one side of the wire disc 9 close to the human leg, and the lower end is connected to the front end of the load ring 44 of the human foot.

[0046] The working process of embodiment 3 is as follows:

[0047] As Figure 6 shown, with the rotation of the ankle joint, the spring-loaded rope 41 is tightened, pulling the wire reel 9. When a certain angle is reached, the magnetic fluid clutch enters the closed locked state as shown in Figure 5 . At this time, with the rotation of the ankle joint, the spring will be stretched into the energy storage stage, Figure 7 the energy storage completion stage.

[0048] As Figure 7 shown, when the foot is no longer pressing the shoe, the ankle joint continues to rotate, and the spring begins to release energy, entering the power assistance stage. After the power assistance ends, the ankle joint continues to rotate, and the rope 42 is stretched, pulling the upper and lower paddle discs 6 and 7 to rotate. At this time, the magnetic rheological clutch is in the closed locked state as shown in Figure 5 , the wire reel 6 and the clutch disc 2 are fixed; under the joint action of the upper and lower paddle discs 6 and 7 and the clutch disc 10, the pin key 23 and the magnetic shielding piece 24 begin to converge to the center in the form of a vortex line, shielding the permanent magnet 16. The magnetic rheological fluid becomes very small through the magnetic field and no longer has viscosity. The magnetic rheological fluid shell 11 and the magnetic rheological fluid brush 12 return to relative rotation, and the clutch enters the separation state. The wire reel recovers the rope under the action of the reset elastic element. At this time, the magnetic fluid clutch is in the initial state as shown in Figure 4 .

Claims

1. A magnetorheological clutch, comprising an upper cover plate (1), a lower cover plate (2), a shaft (3), an upper sealing end cover (4), a lower sealing end cover (5), an upper paddle disc (6), a lower paddle disc (7), a spring (8), a coil (9), a clutch disc (10), a magnetorheological housing (11), a magnetorheological brush (12), a key (23), and a magnetic shielding plate (24); characterized in that: The two ends of the shaft (3) are respectively connected to the center of the upper cover plate (1) and the lower cover plate (2). The shaft (3) near the opposite side of the upper cover plate (1) and the lower cover plate (2) is fitted with an upper paddle disc (6) and a lower paddle disc (7). The upper paddle disc (6) and the lower paddle disc (7) can rotate relative to the shaft (3), the upper cover plate (1) and the lower cover plate (2). The shaft (3) at the opposite side of the upper paddle disc (6) and the lower paddle disc (7) is fitted with an upper sealing end cap (4) and a lower sealing end cap (5). The connection between the upper sealing end cap (4) and the lower sealing end cap (5) and the shaft (3) is sealed. The shaft (3) can rotate relative to the upper sealing end cap (4) and the lower sealing end cap (5). The upper cover plate (1) and the lower cover plate (2) are respectively provided with a set of spring springs (8). One end of the spring spring (8) is fixedly connected to the upper cover plate (1) and the lower cover plate (2), and the other end is fixedly connected to the upper shifter plate (6) or the lower shifter plate (7). A clutch disc (10) is provided between the upper paddle disc (6) and the lower paddle disc (7), and a wire spool (9) is fixedly mounted on the outer circular surface of the clutch disc (10); a magnetorheological housing (11) is fixedly installed at the center of the clutch disc (10), and the clutch disc (10), the wire spool (9), and the magnetorheological housing (11) can rotate relative to the upper paddle disc (6) and the lower paddle disc (7). The shaft (3) passes through the opening at the center of the upper and lower end faces of the magnetorheological housing (11), and the opening is sealed by the upper sealing end cap (4) or the lower sealing end cap (5). The shaft (3) can rotate relative to the upper sealing end cap (4) and the lower sealing end cap (5); the magnetorheological brush (12) is fixedly installed on the shaft (3) and located inside the magnetorheological housing (11), and the magnetorheological housing (11) is filled with magnetorheological fluid. The clutch disc (10) has multiple sets of oblique through grooves I (13) on its side. The upper paddle disc (6) and the lower paddle disc (7) have oblique through grooves II (14) that correspond one-to-one with the oblique through grooves I (13) on their sides. The key (23) is installed in the oblique through groove I (13), and its two ends pass through the corresponding oblique through grooves II (14) on the upper paddle disc (6) and the lower paddle disc (7). A set of shielding plates (24) are installed at both ends of the key (23). On the side of the clutch disc (10), each oblique through groove I (13) is provided with a set of permanent magnet grooves (15) on the side closest to the center of the clutch disc (10), and permanent magnets (16) are installed in the permanent magnet grooves (15); the pin (23) can slide along the oblique through groove I (13) and oblique through groove II (14), so that the shielding sheet (24) covers or opens both ends of the permanent magnet groove (15).

2. The magnetorheological clutch as described in claim 1, characterized in that: The upper cover plate (1) and the lower cover plate (2) are connected by multiple sets of support columns (17), and each set of support columns (17) is located on the outside of the coil (9).

3. The magnetorheological clutch applied to a passive ankle exoskeleton as described in claim 1, characterized in that: The inclination angles of each set of oblique through grooves I (13) on the side of the clutch disc (10) are consistent.

4. The magnetorheological clutch as described in claim 1, characterized in that: The permanent magnet (16) is an axially magnetized cylindrical permanent magnet.

5. The magnetorheological clutch as described in claim 1, characterized in that: The two ends of the shaft (3) are square rods, and the upper cover plate (1) and the lower cover plate (2) are respectively provided with square holes (18). The square rods at both ends of the shaft (3) are respectively inserted into the square holes (18) through clearance fit.

6. The magnetorheological clutch as described in claim 1, characterized in that: The upper cover plate (1) and the lower cover plate (2) are respectively provided with annular guide grooves (19) at the center of their opposite surfaces. The upper sealing end cover (4) and the lower sealing end cover (5) are respectively provided with collars (20). Through the cooperation of the annular guide grooves (19) and the collars (20), the upper sealing end cover (4) and the lower sealing end cover (5) cannot move radially.

7. The magnetorheological clutch as described in claim 6, characterized in that: The upper cover plate (1) and the lower cover plate (2) are provided with a support ring (21) on their opposite surfaces. The support ring (21) is located outside the annular guide groove (19) and is used to support the upper paddle plate (6) or the lower paddle plate (7).

8. The magnetorheological clutch as described in claim 7, characterized in that: The upper cover plate (1) and the lower cover plate (2) are provided with multiple sets of spaced support guide rings (25). The support guide rings (25) are located between the support ring (21) and the annular guide groove (19). The support guide rings (25) are used to support and guide the sliding of the magnetic shielding sheet (24).

9. The magnetorheological clutch as described in claim 1, characterized in that: The magnetorheological housing (11) has a bearing (22) at the opening at the center of the upper and lower end faces, and the inner ring of the bearing (22) is fixedly connected to the shaft (3).

10. A passive ankle exoskeleton, employing a magnetorheological clutch as described in any one of claims 1-9, characterized in that: It also includes rope I (41) and rope II (42); the magnetorheological clutch of the passive ankle exoskeleton is installed on the rear of the leg guard (43) of the lower leg; The upper end of the rope I (41) is connected to the side of the reel (9) away from the human leg, and the lower end is connected to the rear end of the load-bearing ring (44) at the human foot; the rope II (42) is connected to the side of the reel (9) near the human leg, and the lower end is connected to the front end of the load-bearing ring (44) at the human foot.

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