Magnetorheological fluid damper capable of reverse free driving in forward active state

Abstract

The application discloses a magnetorheological fluid damper capable of being reversely freely driven in a positive activation state, which comprises a separator, a rotating shaft, a first magnetorheological fluid damping unit and a second magnetorheological fluid damping unit; the first magnetorheological fluid damping unit and the second magnetorheological fluid damping unit are respectively attached to two sides of the separator; the rotating shaft penetrates through the first magnetorheological fluid damping unit, the separator and the second magnetorheological fluid damping unit; the two magnetorheological fluid damping units are independently controlled, and the rotating shaft is respectively provided with a first one-way bearing and a second one-way bearing with opposite constraint directions; when one of the magnetorheological fluid damping units is activated, the rotating shaft receives torque transmission in the direction constrained by the one-way bearing corresponding to the magnetorheological fluid damping unit and freely rotates in the other direction. The one-way bearing is added in the magnetorheological fluid damper, the damper can still provide free driving in one direction after being activated, and the problem of "sticking to the wall" feeling when separating from the wall in force sensation interaction is solved.

Description

Technical Field

[0001] This invention belongs to the field of damper technology, specifically relating to a magnetorheological fluid damper that can be freely driven in reverse under a positive activation state. Background Technology

[0002] Force sensation is an important sensory channel for people to obtain information from the outside world. Force-sensory interaction can simulate the magnitude of the forces exerted on a person in a real environment, creating a realistic interactive experience. In human-computer interaction, force-sensory reproduction devices mainly use internally integrated actuators to provide force feedback to the operator. Because they can enhance the operator's sense of presence and immersion, and improve the effectiveness and efficiency of human-computer interaction, force-sensory reproduction devices have been widely used in fields such as virtual surgery, rehabilitation training, and teleoperated robots.

[0003] Magnetorheological fluids (MRFs) are intelligent fluids capable of generating rheological effects, typically existing as suspensions. When an external magnetic field is applied, the properties of the MRF change rapidly. Particles form chain-like structures within the MRF, increasing the yield stress and transforming the fluid from a liquid to a near-solid state, while also exhibiting some shear resistance. Therefore, dampers developed based on MRFs can dynamically adjust the magnetic field strength applied to the MRF by changing the current input to the excitation coil, causing variations in the MRF's yield strength and enabling dynamic and continuous control of the output damping force / torque. Thus, MRF dampers based on the rheological effects of MRFs possess characteristics such as being passive, simple in structure, easy to maintain, high in torque density, low in power consumption, and capable of low-voltage operation, making them highly promising actuators in the field of force-sensing interaction.

[0004] Traditional magnetorheological fluid dampers generate resistance that restricts bidirectional rotational motion when the excitation coil is energized and activated. When a user uses a force-sensing device made with a traditional magnetorheological fluid damper to contact a virtual wall, this resistance prevents the user from moving freely when leaving the virtual wall, creating a feeling of being "stuck to the wall." To overcome this problem, existing solutions generally use force / torque sensors to detect the force applied by the user. However, this solution requires other active components in the damper design, which not only increases cost but also leads to increased device size and weight, causing inconvenience in human-computer interaction. Summary of the Invention

[0005] To address the aforementioned issues, this invention proposes a magnetorheological fluid damper that can be freely driven in reverse under a positive activation state, which can eliminate the "sticky" feeling when users interact with a virtual wall without using a force / torque sensor.

[0006] To achieve the above-mentioned technical objectives and effects, the present invention is implemented through the following technical solution:

[0007] This invention provides a magnetorheological fluid damper that can be freely driven in reverse under a positive activation state, comprising: a separator, a rotating shaft, a first magnetorheological fluid damping unit, and a second magnetorheological fluid damping unit;

[0008] The first magnetorheological fluid damping unit and the second magnetorheological fluid damping unit are respectively attached to both sides of the separator;

[0009] The rotating shaft passes through the first magnetorheological fluid damping unit, the separator, and the second magnetorheological fluid damping unit in sequence.

[0010] The first magnetorheological fluid damping unit and the second magnetorheological fluid damping unit are independently controlled. The two units are respectively provided with a first one-way bearing and a second one-way bearing with opposite constraint directions between them and the rotating shaft. When one of the magnetorheological fluid damping units is activated, the rotating shaft receives torque transmission in the direction constrained by the one-way bearing corresponding to the magnetorheological fluid damping unit, and rotates freely in the other direction.

[0011] Optionally, the magnetorheological fluid damper further includes two caps disposed opposite to each other, each cap being connected to the first magnetorheological fluid damping unit and the second magnetorheological fluid damping unit respectively.

[0012] Optionally, both the cap and the separator are equipped with sealing rings, employing step seals for dynamic sealing.

[0013] Optionally, the first magnetorheological fluid damping unit and the second magnetorheological fluid damping unit have the same structure, both including: a rotor, a magnetic ring, a first magnetic isolation ring, a second magnetic isolation ring and a housing arranged coaxially, and a coil;

[0014] The rotor is divided into two parts by a first magnetic isolation ring sleeved on the outside of the rotating shaft, and each part is sleeved on the outside of the rotating shaft by the first one-way bearing and the second one-way bearing, respectively.

[0015] The magnetic ring is sleeved on the outside of the rotor and the first magnetic isolation ring;

[0016] The number of the second magnetic shielding rings is two, which are respectively sleeved on the outer side of the two parts of the rotor and are in contact with the two axial outer end faces of the magnetic guide ring;

[0017] The coil is wound around the radial outer surface of the magnetic ring and led out through the wire outlet hole on the side of the housing;

[0018] The outer casing is wrapped around the second magnetic shielding ring, the coil, and the rotor.

[0019] A working gap is provided between the first magnetic isolation ring, the second magnetic isolation ring, the magnetic guiding ring, the rotor and the outer shell, and the working gap is filled with magnetorheological fluid.

[0020] Optionally, the shaft and rotor are respectively provided with a first convex key and a second convex key, and the shaft and rotor are respectively connected to a first one-way bearing and a second one-way bearing through the first convex key and the second convex key to transmit radial torque.

[0021] Optionally, the first magnetic isolation ring and the two second magnetic isolation rings allow the magnetic field to pass through the magnetorheological fluid, the rotor, the magnetic guide ring and the outer shell, forming a serpentine magnetic circuit.

[0022] Optionally, the rotor is fixed to the first magnetic isolation ring by bolts; the outer casing, the magnetic guide ring, the second magnetic isolation ring, and the separator are fixed together by bolts.

[0023] Optionally, the rotor, magnetic ring, and housing are all made of DT4C electrical pure iron, the first and second magnetic isolation rings are both made of non-magnetic metal materials, and the coil is made of enameled copper wire.

[0024] Optionally, the magnetorheological fluid is an MRF-122EG type magnetorheological fluid.

[0025] Optionally, the working gap is 0.2-2mm.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] Unlike traditional magnetorheological fluid dampers that restrict bidirectional rotational motion after activation, this invention adds a one-way bearing to the magnetorheological fluid damper, allowing the damper to still provide free drive in one direction after activation. This effectively solves the problem of the "sticking to the wall" feeling when detaching from the wall during force interaction.

[0028] To address the "sticky" feeling experienced by users in force-sensory interaction, the damper of this invention avoids the use of force / torque sensors, which not only simplifies the interaction device and saves costs, but also greatly enhances the realism of the user's interaction with the virtual wall. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:

[0030] Figure 1 This is a cross-sectional view of a magnetorheological fluid damper according to an embodiment of the present invention.

[0031] Figure 2 This is a side sectional view of a magnetorheological fluid damper according to an embodiment of the present invention;

[0032] Figure 3 This is a schematic diagram of the overall structure of a magnetorheological fluid damper according to an embodiment of the present invention;

[0033] Figure 4 This is a schematic diagram of the rotor structure according to an embodiment of the present invention;

[0034] Figure 5 This is a schematic diagram of the structure of a magnetic ring according to an embodiment of the present invention;

[0035] Figure 6 This is a schematic diagram of the structure of a magnetic shielding ring according to an embodiment of the present invention.

[0036] Figure 7 This is a schematic diagram of the separator according to an embodiment of the present invention;

[0037] Figure 8 This is a schematic diagram of the outer shell of one embodiment of the present invention;

[0038] Figure 9 This is a schematic diagram of the structure of the cap according to an embodiment of the present invention;

[0039] Figure 10 This is a schematic diagram of the structure of a rotating shaft according to an embodiment of the present invention;

[0040] Figure 11(a) is one of the assembled cross-sectional views of the magnetic shielding ring, the magnetic conductive ring and the housing according to an embodiment of the present invention;

[0041] Figure 11(b) is a second assembled cross-sectional view of the magnetic shielding ring, the magnetic conductive ring, and the outer shell according to an embodiment of the present invention;

[0042] Figure 12 This is a schematic diagram of a serpentine magnetic circuit according to an embodiment of the present invention;

[0043] in:

[0044] 1-Shaft 1, 2-Cap, 3-Outer shell, 4-Coil, 5-Outlet hole, 6-Separator, 7-First magnetic isolation ring, 8-Sealing ring, 9-First one-way bearing, 10-Sealing ring, 11-Second magnetic isolation ring, 12-Rotor, 13-Third bolt, 14-Magnetic guide ring, 15-Working gap, 18-Magnetorheological fluid, 1-1-First convex key, 12-1-Second convex key, 1201-First threaded hole, 1401-Second threaded hole, 601-Third threaded hole, 301-Fourth threaded hole, 302-Fifth threaded hole, 701-Sixth threaded hole, 303-Seventh threaded hole, 201-Eighth threaded hole, 202-Ninth threaded hole, 16-First bolt, 17-Second bolt, 19-Serpentine magnetic circuit. Detailed Implementation

[0045] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may include different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0047] In the description of this invention, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0048] In the description of this invention, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0049] The application principle of the present invention will be described in detail below with reference to the accompanying drawings.

[0050] like Figure 1-3As shown, the present invention provides a magnetorheological fluid damper that can be freely driven in reverse under positive activation state, including: a separator 6, a rotating shaft 1, a first magnetorheological fluid damping unit and a second magnetorheological fluid damping unit, and two covers 2 arranged opposite to each other;

[0051] The first magnetorheological fluid damping unit and the second magnetorheological fluid damping unit are respectively attached to both sides of the separator 6;

[0052] The rotating shaft 1 passes through the first magnetorheological damping unit, the separator 6, and the second magnetorheological damping unit in sequence.

[0053] The first magnetorheological fluid damping unit and the second magnetorheological fluid damping unit are independently controlled. The two units are respectively provided with a first one-way bearing 9 and a second one-way bearing with opposite constraint directions between them and the rotating shaft 1. When one of the magnetorheological fluid damping units is activated, the rotating shaft 1 receives torque transmission in the direction constrained by the one-way bearing corresponding to the magnetorheological fluid damping unit, and rotates freely in the other direction.

[0054] Each cap 2 is connected to the first magnetorheological fluid damping unit and the second magnetorheological fluid damping unit, respectively.

[0055] Unlike traditional magnetorheological fluid dampers that restrict bidirectional rotational motion after activation, this invention incorporates unidirectional bearings (i.e., a first unidirectional bearing 9 and a second unidirectional bearing) into the magnetorheological fluid damper. This allows the damper to maintain free drive in one direction even after activation, effectively solving the problem of a "sticky" feeling when detaching from a wall during force-sensory interaction.

[0056] In one specific embodiment of the present invention, both the cover 2 and the separator 6 are provided with sealing rings 10, which are stent seals and play a dynamic sealing role.

[0057] In one specific embodiment of the present invention, the first magnetorheological fluid damping unit and the second magnetorheological fluid damping unit have the same structure and are symmetrically installed on both sides of the separator 6. Each includes: a rotor 12, a magnetic ring 14, a first magnetic isolation ring 7, a second magnetic isolation ring 11 and a housing 3 arranged coaxially, and a coil 4.

[0058] The rotor 12 is divided into two parts by a first magnetic isolation ring 7 sleeved on the outside of the rotating shaft 1, and each part is sleeved on the outside of the rotating shaft 1 by the first one-way bearing 9 and the second one-way bearing respectively.

[0059] The magnetic ring 14 is sleeved on the outside of the rotor 12 and the first magnetic isolation ring 7; from Figure 1 As can be seen, the axial dimension of the magnetic ring 14 is smaller than the sum of the axial dimensions of the rotor 12 and the first magnetic isolation ring 7, that is, the magnetic ring 14 only covers part of the rotor 12.

[0060] The number of the second magnetic shielding rings 11 is two, which are respectively sleeved on the outer side of the two parts of the rotor 12 and are in contact with the two axial outer end faces of the magnetic guide ring 14;

[0061] The coil 4 is wound around the radial outer surface of the magnetic ring 14 and led out through the wire outlet 5 on the side of the housing 3; in the specific implementation, the first magnetorheological fluid damping unit and the second magnetorheological fluid damping unit on the left and right sides are respectively equipped with independent coils 4 for control, and are independent of each other.

[0062] The outer casing 3 surrounds the second magnetic shielding ring 11, the coil 4, and the rotor 12, from... Figure 1 As can be seen, the outer casing 3 covers part of the rotor 12;

[0063] A working gap 15 is provided between the first magnetic isolation ring 7, the second magnetic isolation ring 11, the magnetic guiding ring 14, the rotor 12, and the outer shell 3. The working gap 15 is filled with magnetorheological fluid 18. The magnetic field passes through the magnetorheological fluid 18, the rotor 12, the magnetic guiding ring 14, and the outer shell 3 to form a serpentine magnetic circuit 19. See details. Figure 12 .

[0064] In one specific embodiment of the present invention, the rotating shaft 1 and the rotor 12 are respectively provided with a first convex key 1-1 and a second convex key 12-1. The rotating shaft 1 and the rotor 12 are respectively connected to the first one-way bearing 9 and the second one-way bearing through the first convex key 1-1 and the second convex key 12-1 to transmit radial torque.

[0065] In one specific embodiment of the present invention, the rotor 12 is fixed to the first magnetic isolation ring 7 by bolts; the outer shell 3, the magnetic guide ring 14, the second magnetic isolation ring 11 and the separator 6 are fixed together by bolts.

[0066] In one specific embodiment of the present invention, the rotor 12, the magnetic ring 14, and the outer shell 3 are all made of DT4C electrical pure iron, the first magnetic isolation ring 7 and the second magnetic isolation ring 11 are both made of non-magnetic metal materials, and the coil 4 is made of enameled copper wire. DT4C has high magnetic permeability, while non-metallic materials have low magnetic permeability. Magnetic flux passes through the magnetic material and avoids the non-magnetic metal material, thereby forming a serpentine magnetic circuit.

[0067] In one specific embodiment of the present invention, the magnetorheological fluid is MRF-122EG type magnetorheological fluid. MRF-122EG has low viscosity, and when zero current is applied to the system, the magnetorheological fluid damper will have minimal friction, thereby giving the magnetorheological fluid damper higher transparency when it is not activated. In practical applications, other types of magnetorheological fluids can also be selected, but those with the lowest possible viscosity should be chosen.

[0068] In one specific embodiment of the present invention, the working gap is 0.2-2mm, and preferably, the working gap is set to 0.25mm.

[0069] The damper that can be freely driven in reverse in the activated state according to the present invention will be described in detail below with reference to a specific embodiment.

[0070] like Figure 1-3 As shown, the present invention proposes a damper that can be freely driven in reverse in the activated state, mainly including: a rotating shaft 1, a cover 2, a shell 3, a coil 4, a wire outlet 5, a separator 6, a first magnetic isolation ring 7, a sealing ring 8, a first one-way bearing 9, a second one-way bearing, a sealing ring 10, a second magnetic isolation ring 11, a rotor 12, a magnetic guide ring 14, and a magnetorheological fluid 18;

[0071] A sealing ring 8 is fitted between the cover 2 and the outer shell 3. In specific implementation, the sealing ring 8 can be a nitrile rubber O-ring, or other sealing devices that can achieve a sealing effect, which play a static sealing role.

[0072] Both the separator 6 and the cover 2 have a sealing ring 10 embedded inside, which is a step seal and plays a dynamic sealing role.

[0073] A working gap 15 is provided between the first magnetic isolation ring 7, the second magnetic isolation ring 11, the magnetic guide ring 14, the rotor 12 and the outer shell 3. The working gap 15 is filled with MRF-122EG type magnetorheological fluid 18, and the working gap of the magnetorheological fluid 18 is 0.25mm. A coil 4 is wound on the radial outer surface of the magnetic guide ring 14. The coil 4 is led out to the outside of the outer shell 3 through the wire outlet hole 5. The coils 4 on the left and right sides are independent of each other and can be controlled separately. The rotor 12 is separated into two parts by the magnetic isolation ring 7, and they are directly fixed together by the third bolt 13. Finally, the first magnetorheological fluid damping unit and the second magnetorheological fluid damping unit with the same structure are installed symmetrically on the left and right sides and separated by the separator 6.

[0074] like Figure 2 , 4 As shown, the rotor 12 has a first threaded hole 1201 and a second convex key 12-1. A third bolt 13 fixes the rotor 12 to the magnetic shielding ring 7 through the first threaded hole 1201. The rotor 12 cooperates with the first one-way bearing 9 or the second one-way bearing through the second convex key 12-1, thereby achieving stable radial torque transmission. The rotor 12 is made of magnetically permeable metal material (DT4C) electrical pure iron, which has high magnetic permeability.

[0075] like Figure 5 , Figure 7 , Figure 8As shown in Figures 11(a) and 11(b), the magnetic ring 14 has a second threaded hole 1401, the separator 6 has a third threaded hole 601, and the outer casing 3 has a fourth threaded hole 301 and a fifth threaded hole 302. The first bolt 16 and the second bolt 17 connect the outer casing 3, the magnetic ring 14, the magnetic isolation ring 11, and the separator 6 in series from the left and right sides through the fourth threaded hole 301, the fifth threaded hole 302, the second threaded hole 1401, and the third threaded hole 601, respectively. The magnetic ring 14 is made of electrically pure iron (DT4C), a magnetically conductive metal material, while the separator 6 is made of a non-magnetically conductive metal material. DT4C has high magnetic permeability, while non-metallic materials have low magnetic permeability.

[0076] like Figure 6 As shown, the magnetic shielding ring 7 has a sixth threaded hole 701, and the third bolt 13 is fixed to the rotor 12 through the sixth threaded hole 701. Preferably, the magnetic shielding ring 7 is made of a non-magnetic metal material, and the non-metallic material has low magnetic permeability.

[0077] like Figure 8 As shown, the outer casing 3 has a seventh threaded hole 303, through which countersunk bolts fix the outer casing 3 to the cover 2. The outer casing 3 is made of magnetically conductive metal material (DT4C) electrical pure iron.

[0078] like Figure 9 As shown, the cover 2 has an eighth threaded hole 201 and a ninth threaded hole 202. The countersunk bolts fix the cover 2 to the outer shell 3 through the eighth threaded hole 201, and the magnetorheological fluid 18 is poured into the working gap 15 inside the magnetorheological fluid damper through the ninth threaded hole 202. The cover 2 is made of non-magnetic metal material.

[0079] like Figure 10 As shown, the rotating shaft 1 is provided with a protruding key 1-1. The protruding key 1-1 is used to connect the rotating shaft 1 and the one-way bearing 9 to ensure the transmission of torque when the one-way bearing 9 constrains the rotating shaft 1.

[0080] In this invention, the rotor 12 and the one-way bearing 9 are bidirectionally constrained and cooperate as a whole; while the shaft 1 and the one-way bearing 9 are constrained only in one direction. Therefore, the shaft 1 can be subjected to the torque transmitted by the rotor 12 in one direction, while rotating freely in the other direction.

[0081] When the magnetorheological fluid damper of this invention is activated, an excitation current is input to the coil 4 in one side of the damper to generate a magnetic field. The magnetic field passes through the magnetorheological fluid 18, the rotor 12, the magnetic ring 14, and the outer shell 3 to form a serpentine closed loop 19, causing the magnetorheological fluid 18 to undergo a rheological effect. After activation, the magnetorheological fluid damper can provide force feedback in one direction and drive freely in the other direction due to the unidirectional constraint of the one-way bearing 9 that cooperates with the shaft 1.

[0082] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only used to facilitate the description of the present invention and to simplify the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of the present invention.

[0083] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A magnetorheological fluid damper that can be freely driven in reverse under a positively activated state, characterized in that, include: Separator (6), rotating shaft (1), first magnetorheological fluid damping unit and second magnetorheological fluid damping unit; The first magnetorheological fluid damping unit and the second magnetorheological fluid damping unit are respectively attached to both sides of the separator (6); The rotating shaft (1) passes through the first magnetorheological fluid damping unit, the separator (6), and the second magnetorheological fluid damping unit in sequence; The first magnetorheological fluid damping unit and the second magnetorheological fluid damping unit are independently controlled. The two units are respectively provided with a first one-way bearing (9) and a second one-way bearing with opposite constraint directions between them and the rotating shaft. When one of the magnetorheological fluid damping units is activated, the rotating shaft (1) receives torque transmission in the direction constrained by the one-way bearing corresponding to the magnetorheological fluid damping unit, and rotates freely in the other direction. The first magnetorheological fluid damping unit and the second magnetorheological fluid damping unit have the same structure, both including: a rotor (12) arranged coaxially, a magnetic ring (14), a first magnetic isolation ring (7), a second magnetic isolation ring (11) and a shell (3), and a coil (4); The rotor (12) is divided into two parts by a first magnetic isolation ring (7) sleeved on the outside of the rotating shaft (1), and each part is sleeved on the outside of the rotating shaft (1) by the first one-way bearing (9) and the second one-way bearing respectively. The magnetic ring (14) is sleeved on the outside of the rotor (12) and the first magnetic isolation ring (7); The number of the second magnetic isolation rings (11) is 2, which are respectively sleeved on the outer side of the two parts of the rotor (12) and are in contact with the two axial outer end faces of the magnetic guide ring (14); The coil (4) is wound around the radial outer surface of the magnetic ring (14) and led out through the wire outlet (5) on the side of the outer casing (3); The outer casing (3) is wrapped around the outside of the second magnetic shielding ring (11), the coil (4) and the rotor (12); A working gap (15) is provided between the first magnetic isolation ring (7), the second magnetic isolation ring (11), the magnetic guide ring (14), the rotor (12) and the outer shell (3), and the working gap (15) is filled with magnetorheological fluid (18). The first magnetic isolation ring (7) and the two second magnetic isolation rings (11) allow the magnetic field to pass through the magnetorheological fluid (18), the rotor (12), the magnetic guide ring (14) and the outer shell (3), forming a serpentine magnetic circuit (19).

2. The magnetorheological fluid damper that can be freely driven in reverse under a positively activated state according to claim 1, characterized in that, The magnetorheological fluid damper also includes two covers (2) arranged opposite to each other, each cover (2) being connected to the first magnetorheological fluid damping unit and the second magnetorheological fluid damping unit respectively.

3. The magnetorheological fluid damper that can be freely driven in reverse under a positively activated state according to claim 2, characterized in that: Both the cover (2) and the separator (6) are equipped with sealing rings (10), which are step seals used for dynamic sealing.

4. The magnetorheological fluid damper that can be freely driven in reverse under a positively activated state according to claim 1, characterized in that: The shaft (1) and rotor (12) are respectively provided with a first convex key (1-1) and a second convex key (12-1). The shaft (1) and rotor (12) are connected to the first one-way bearing (9) and the second one-way bearing respectively through the first convex key (1-1) and the second convex key (12-1) to transmit radial torque.

5. A magnetorheological fluid damper that can be freely driven in reverse under a positively activated state, as described in claim 1, characterized in that: The rotor (12) is fixed to the first magnetic isolation ring (7) by bolts; the outer shell (3), the magnetic guide ring (14), the second magnetic isolation ring (11) and the separator (6) are fixed together by bolts.

6. A magnetorheological fluid damper that can be freely driven in reverse under a positively activated state, as described in claim 1, characterized in that: The rotor (12), magnetic ring (14) and outer shell (3) are all made of DT4C electrical pure iron, the first magnetic isolation ring (7) and the second magnetic isolation ring (11) are both made of non-magnetic metal material, and the coil (4) is made of enameled copper wire.

7. A magnetorheological fluid damper that can be freely driven in reverse under a positively activated state, as described in claim 1, characterized in that: The magnetorheological fluid (18) is an MRF-122EG type magnetorheological fluid.

8. A magnetorheological fluid damper that can be freely driven in reverse under a positively activated state, as described in claim 1, characterized in that: The working gap (15) is 0.2-2mm.

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