Anti-settling magnetorheological damper

Abstract

The anti-settling magnetorheological damper comprises a left end cover, a piston rod, a cylinder, a damping piston, a floating piston and a right end cover; the left end cover is provided with a piston rod guide hole; the floating piston and the right end cover are filled with inert gas, and the floating piston and the left end cover are filled with magnetorheological fluid; the damping piston is provided with a damping channel; the damping piston is provided with a groove, and the groove is provided with a coil; the piston rod is provided with a stirring sheet made of memory alloy, one end of the stirring sheet is fixedly connected with the piston rod; and the piston rod is provided with an annular groove. The piston rod and the memory alloy are combined to form a specific structure, the damper is assembled when the memory alloy is not unfolded, the original damper assembly process does not need to be changed, and the existing damper assembly tool equipment does not need to be modified, the technical scheme is easy to implement, the damper works, the temperature of the magnetorheological fluid is increased, the memory alloy is unfolded, the magnetorheological fluid is stirred, and the anti-settling purpose of the magnetorheological fluid is achieved.

Description

Technical Field

[0001] This invention relates to automotive shock absorbers, and more particularly to a magnetorheological shock absorber that can prevent magnetorheological fluid precipitation. Background Technology

[0002] Magnetorheological fluids (MRFs) are a novel type of fluid with controllable flowability. The viscosity of a MRF corresponds to its magnetic flux; it exhibits low-viscosity Newtonian fluid characteristics in the absence of an external magnetic field, but becomes a high-viscosity, low-flow Bingham fluid under an applied magnetic field. These changes are reversible, and the conversion is energy-efficient, easy to control, and achieves millisecond-level response. MRF vibration dampers developed using these properties are characterized by simple structure, rapid response, and a wide dynamic range of damping force, making them a high-performance semi-active control device.

[0003] In magnetorheological (MR) vibration dampers, addressing the sedimentation problem of the magnetorheological fluid is a key research focus. In existing cylindrical MR vibration dampers, a common method to improve sedimentation is to reduce the diameter of the magnetic particles in the MR fluid. However, MR fluids with smaller magnetic particle diameters are expensive, costly, and the results are not ideal. Chinese patent CN107725663A proposes an anti-sedimentation MR fluid vibration damper, which prevents sedimentation by adding permanent magnets to change the force state of the magnetic particles under the influence of a magnetic field. However, the magnetic particles are distributed along their magnetic lines of force, causing some particles to adhere to the permanent magnets, reducing the concentration of usable magnetic particles in the MR fluid. Furthermore, the proximity of the permanent magnets to the magnetic flux channels can cause blockage, significantly reducing the performance of the MR vibration damper. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides an anti-precipitation magnetorheological damper. This invention utilizes a piston rod combined with a shape memory alloy to form a specific structure. The damper is assembled at a low temperature when the shape memory alloy is not yet unfolded, eliminating the need to change the original damper assembly process or modify existing assembly tooling and equipment. The technical solution is easy to implement. When the damper is working, the temperature of the magnetorheological fluid rises, the shape memory alloy unfolds, and the magnetorheological fluid is agitated, achieving the purpose of preventing precipitation in the magnetorheological fluid.

[0005] The technical solution of the present invention:

[0006] A magnetorheological damper for preventing sedimentation includes a left end cap, a piston rod, a cylinder, a damping piston, a floating piston, and a right end cap. The left end cap is connected to and sealed to the cylinder, and has a piston rod guide hole. One end of the piston rod extends from the piston rod guide hole and is connected to a vehicle body support, while the other end is connected to the damping piston. The piston rod slides within the piston rod guide hole and is sealed by a seal. The damping piston is located inside the cylinder and slides within the cylinder's inner circumferential surface. The right end cap is connected to and sealed to the cylinder, and a vehicle body support is connected to the outer side of the right end cap. The floating piston is located between the damping piston and the right end cap, and slides within the cylinder's inner circumferential surface and is sealed by a seal. An inert gas is filled between the piston and the right end cap, and a magnetorheological fluid is filled between the floating piston and the left end cap. The damping piston has a set of damping channels evenly distributed circumferentially and axially extending. Multiple axially distributed grooves are provided on the outer circumferential surface of the damping piston, and coils are placed in these grooves. A set of stirring plates made of shape memory alloy is provided on the piston rod between the left end cap and the damping piston, with one end of each stirring plate fixedly connected to the piston rod. An annular groove is provided on the piston rod. During vibration damping assembly, external force is first used to deform the stirring plates, causing them to adhere tightly to the piston rod and be located in the annular groove, followed by the assembly process. During vibration damping operation, the stirring plates are heated and return to their original shape, unfolding to form a stirring mechanism.

[0007] Compared with the prior art, the anti-precipitation magnetorheological damper of the present invention has a stirring plate made of shape memory alloy on the piston rod. During the assembly of the damper, the shape memory alloy is first deformed by external force, closely attached to the piston rod and located in the annular groove, avoiding interference with the assembly equipment during the assembly process. Therefore, it does not require changes to the original assembly process or the original assembly equipment, and has the advantage of being easy to implement. During the use of the damper, the shape memory alloy closely attached to the piston rod is heated and expands to form a stirring mechanism. The shape memory alloy moves back and forth with the piston rod, stirring the magnetorheological fluid, achieving the purpose of preventing precipitation of the magnetorheological fluid, so that the magnetic particles in the magnetorheological fluid are evenly distributed and the damping force is effectively improved.

[0008] As an optimization, in the aforementioned anti-sedimentation magnetorheological damper, a permanent magnet tile is provided on the groove between the damping piston and the coil. This structure, with the permanent magnet tile, further enhances the magnetic field, thereby increasing the damping force of the damper; and in the event of power failure or coil damage, it provides a certain magnetic field to maintain the magnetorheological fluid in a Bingham fluid state, preventing damper failure.

[0009] As an optimization, in the aforementioned anti-settling magnetorheological vibration damper, a spring is provided on the side of the floating piston near the damping piston, and the spring is fixedly connected to the floating piston. Thus, under extreme road conditions, the spring limits the stroke of the damping piston. Furthermore, in the aforementioned anti-settling magnetorheological vibration damper, a liner is provided on the end of the spring away from the floating piston, and the liner is fixedly connected to the spring.

[0010] As an optimization, in the aforementioned anti-settling magnetorheological vibration damper, sealing rings are provided at both ends of the outer circumferential surface of the damping piston. Providing sealing rings at both ends of the damping piston prevents it from shaking during operation, avoids friction between the damping piston and the cylinder, thus preventing wear and improving the reliability and service life of the damper.

[0011] As an optimization, in the aforementioned anti-precipitation magnetorheological damper, the inert gas can be nitrogen.

[0012] As an optimization, in the aforementioned anti-sedimentation magnetorheological damper, the agitator is welded to the piston rod. Using welding to connect the agitator to the piston rod ensures reliability and is easy to implement.

[0013] As an optimization, in the aforementioned anti-precipitation magnetorheological damper, the agitator can be a nickel-titanium-based shape memory alloy. Nickel-titanium-based shape memory alloys are widely used, have a relatively stable structure, and a long service life. Attached Figure Description

[0014] Figure 1 This is a structural schematic diagram (cross-sectional view) of the magnetorheological vibration damper with anti-precipitation of the present invention.

[0015] Figure 2 yes Figure 1 Enlarged view of the middle structure;

[0016] Figure 3 yes Figure 1 Cross-sectional view of a moderately damped piston;

[0017] Figure 4 This is a partial structural diagram of the agitator plate after it has been unfolded in this invention;

[0018] Figure 5 This is a partial structural diagram of the agitator plate after it is closed in this invention.

[0019] The labels in the attached diagram are:

[0020] 1-Left end cap; 101-Piston rod guide hole; 2-Piston rod; 21-Annular groove; 3-Cylinder; 4-Damping piston; 401-Damping channel; 402-Groove; 5-Floating piston; 6-Right end cap; 7-Body support; 8-Car support; 9-Coil; 10-Agitator; 11-Permanent magnet; 12-Spring; 13-Liner; 14-Sealing ring. Detailed Implementation

[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments, but this should not be construed as limiting the present invention. In the following embodiments, any techniques not described in detail are conventional technical means or common knowledge in the art.

[0022] See Figures (1-5) for an example:

[0023] A magnetorheological damper for preventing sedimentation includes a left end cover 1, a piston rod 2, a cylinder 3, a damping piston 4, a floating piston 5, and a right end cover 6. The left end cover 1 is connected to and sealed to the cylinder 3, and has a piston rod guide hole 101. One end of the piston rod 2 extends from the piston rod guide hole 101 and is connected to a vehicle body support 7, while the other end is connected to the damping piston 4. The piston rod 2 slides in conjunction with the piston rod guide hole 101 and is sealed by a seal. The damping piston 4 is located inside the cylinder 3 and slides in conjunction with the inner circumferential surface of the cylinder 3. The right end cover 6 is connected to and sealed to the cylinder 3, and a vehicle body support 8 is connected to the outer side of the right end cover 6. The floating piston 5 is located between the damping piston 4 and the right end cover 6, and slides in conjunction with the inner circumferential surface of the cylinder 3 and is sealed by a seal. An inert gas is filled between the piston 5 and the right end cap 6, and a magnetorheological fluid is filled between the floating piston 5 and the left end cap 1. The damping piston 4 has a set of damping channels 401 that are evenly distributed around the circumference and axially connected. The outer circumferential surface of the damping piston 4 has multiple grooves 402 that are axially distributed, and coils 9 are provided in the grooves 402. The piston rod 2 has a set of stirring plates 10 made of shape memory alloy at the part between the left end cap 1 and the damping piston 4. One end of the stirring plate 10 is fixedly connected to the piston rod 2. The piston rod 2 has an annular groove 21. When the shock absorber is assembled, the stirring plate 10 is first deformed by external force so that it is close to the piston rod 2 and located in the annular groove 21, and then the assembly process is carried out. During the use of the shock absorber, the stirring plate 10 is heated and returns to its original shape, unfolding to form a stirring mechanism.

[0024] In this embodiment, a permanent magnet 11 is provided on the groove 402 between the damping piston 4 and the coil 9. The permanent magnet 11 can further enhance the magnetic field, thereby increasing the damping force of the shock absorber; and in the event of power failure or coil damage, it provides a certain magnetic field to prevent the shock absorber from failing.

[0025] In this embodiment, a spring 12 is provided on the side of the floating piston 5 near the damping piston 4, and the spring 12 is fixedly connected to the floating piston 5.

[0026] In this embodiment, a liner 13 is provided at one end of the spring 12 away from the floating piston 5, and the liner 13 is fixedly connected to the spring 12. By providing the liner 13 on the spring 12, the liner 13 replaces the spring 12 in contact with the damping piston 4, increasing the force-bearing area and allowing the damping piston 4 to compress the spring 12 more effectively.

[0027] In this embodiment, sealing rings 14 are provided at both ends of the outer peripheral surface of the damping piston 4. This arrangement can prevent the damping piston from shaking during operation.

[0028] In this embodiment, the inert gas is nitrogen.

[0029] In this embodiment, the stirring plate 10 is welded to the piston rod 2. Welding the stirring plate 10 to the piston rod 2 ensures high reliability and ease of implementation.

[0030] In this embodiment, the stirring plate 10 is a nickel-titanium-based shape memory alloy. The deformation temperature of the nickel-titanium-based shape memory alloy can be modulated; in this embodiment, the deformation temperature is 60°C.

[0031] During vibration damper assembly, the agitator 10 is first deformed by external force, closely adhering to the piston rod 2 and positioned within the annular groove 21, before the assembly process begins. (During assembly, because the agitator 10 contracts into the annular groove 21 on the piston rod 2, the outer contour of the piston rod 2 remains unchanged compared to conventional products, allowing for automated assembly using existing equipment.)

[0032] When the vibration damper is working, coil 9 is energized. The magnetorheological fluid, under the influence of the magnetic field generated by coil 9 and the magnetic field generated by permanent magnet 11, transforms from a Newtonian fluid (without a magnetic field) to a Bingham fluid (under a strong magnetic field). The suspended particles in the magnetorheological fluid change from magnetically neutral to strongly magnetic, interacting with each other and transforming into a macroscopic columnar structure. This causes it to instantly change from a liquid to a viscoplastic substance, thus altering its rheological properties and exhibiting mechanical properties similar to those of a solid. (See appendix) Figure 1When piston rod 2 drives damping piston 4 to move from right to left, damping piston 4 will squeeze the magnetorheological fluid on the left side of damping piston 4, thereby causing it to pass through damping channel 401. The magnetorheological fluid undergoes shear flow, generating damping force. When piston rod 2 drives damping piston 4 to return from left to right, damping piston 4 will squeeze the magnetorheological fluid on the right side of damping piston 4, thereby causing it to pass through damping channel 401, completing the return stroke. (During the shock absorber damping process in the above embodiment, if the vehicle vibration is large, damping piston 4 will contact the liner 13 on spring 12 and compress spring 12. At this time, spring 12 plays the role of limiting the stroke of damping piston of shock absorber, and also provides part of the damping force.) During the operation of shock absorber, stirring plate 10 is heated and unfolds into stirring mechanism, and moves back and forth with piston rod 2 to stir magnetorheological fluid, thereby effectively preventing magnetorheological fluid from settling.

[0033] In implementing this invention, the agitator 10 can be made of a shape memory alloy with a single-pass memory effect or a shape memory alloy with a double-pass memory effect. When a shape memory alloy with a single-pass memory effect is used, it will not retract after unfolding during use on a vehicle. When it has a double-pass memory effect, after the vehicle stops, the shock absorber stops working, and the temperature drops, the agitator 10 will retract, making it convenient for disassembly and reassembly during maintenance.

[0034] In this application, the directional terms "left" and "right" are relative to the illustration and do not constitute a limitation on the scheme of this application.

[0035] The foregoing general description of the invention and its specific embodiments should not be construed as a limitation on the technical solution of the invention. Those skilled in the art, based on the disclosure of this application, can add, reduce, or combine the disclosed technical features in the foregoing general description and / or specific embodiments (including examples) without departing from the constituent elements of the invention, to form other technical solutions within the scope of protection of this application.

Claims

1. A sedimentation-preventing magneto-rheological damper, comprising a left end cover (1), a piston rod (2), a cylinder (3), a damping piston (4), a floating piston (5) and a right end cover (6); the left end cover (1) is connected with and sealed to the cylinder (3), and a piston rod guide hole (101) is arranged on the left end cover (1); one end of the piston rod (2) extends out of the piston rod guide hole (101) and is connected with a vehicle body support (7), and the other end is connected with the damping piston (4); the piston rod (2) is in sliding fit with the piston rod guide hole (101) and is sealed by a sealing member; the damping piston (4) is arranged inside the cylinder (3) and is in sliding fit with the inner circumferential surface of the cylinder (3); the right end cover (6) is connected with and sealed to the cylinder (3), and a vehicle seat support (8) is connected to the outer side surface of the right end cover (6); the floating piston (5) is arranged between the damping piston (4) and the right end cover (6), and is in sliding fit with the inner circumferential surface of the cylinder (3) and is sealed by a sealing member; inert gas is filled between the floating piston (5) and the right end cover (6), and magneto-rheological fluid is filled between the floating piston (5) and the left end cover (1); a group of damping channels (401) which are uniformly distributed along the circumference and axially penetrate through are arranged on the damping piston (4); a plurality of grooves (402) which are distributed along the axial direction are arranged on the outer circumferential surface of the damping piston (4), and a coil (9) is arranged in each groove (402); a group of stirring pieces (10) made of memory alloy are arranged on the part of the piston rod (2) between the left end cover (1) and the damping piston (4), and one end of each stirring piece (10) is fixedly connected with the piston rod (2); an annular groove (21) is arranged on the piston rod (2), and during assembly of the damper, an external force is used to make the stirring pieces (10) deform, so that the stirring pieces (10) are tightly attached to the piston rod (2) and located in the annular groove (21), and then the assembly process is performed; during use of the damper, the stirring pieces (10) recover to the original shape due to heat and expand to form a stirring mechanism.

2. The sedimentation-preventive magneto-rheological damper according to claim 1, characterized in that: A permanent magnet tile (11) is arranged on the groove (402) between the damping piston (4) and the coil (9).

3. The sedimentation-preventing magneto-rheological damper according to claim 2, characterized in that: A spring (12) is arranged on one side of the floating piston (5) close to the damping piston (4), and the spring (12) is fixedly connected with the floating piston (5).

4. The sedimentation-preventing magneto-rheological damper according to claim 3, characterized in that: A backing plate (13) is arranged on one end of the spring (12) away from the floating piston (5), and the backing plate (13) is fixedly connected with the spring (12).

5. The sedimentation-preventing magneto-rheological damper according to claim 4, characterized in that: Sealing rings (14) are arranged at both ends of the outer circumferential surface of the damping piston (4).

6. The sedimentation-preventive magneto-rheological damper according to any one of claims 1 to 5, characterized in that: The inert gas is nitrogen.

7. The sedimentation-preventing magneto-rheological damper according to claim 6, characterized in that: The stirring pieces (10) are welded to the piston rod (2).

8. The sedimentation-preventing magneto-rheological damper according to claim 7, characterized in that: The stirring pieces (10) are made of nickel-titanium-based shape memory alloy.

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