Self-powered self-sensing magnetorheological damper

Abstract

The invention discloses a self-powered and self-sensing magnetorheological damper which comprises a damper shell. The piston rod is axially and movably arranged in the damper shell; the incremental coil is mounted on the piston rod; the magnetic resistance coding structure is mounted on the piston rod; the U-shaped magnet is fixedly arranged on the damper shell and is arranged opposite to the incremental coil to form a variable magnetic flux system; the magnetoresistive sensor array is fixedly arranged in the damper shell and used for reading the magnetoresistive coding structure; the rectification and energy storage module is electrically connected with the incremental coil; the signal conditioning module is electrically connected with the magnetoresistive sensor array; the magnetorheological cavity is arranged in the damper shell, and magnetorheological fluid is filled in the magnetorheological cavity; the piston head is arranged on the piston rod and located in the magnetorheological cavity; the invention aims to provide the intelligent magneto-rheological damper integrating the functions of self-power supply, self-sensing, absolute displacement measurement and passive communication, and a solution with low energy consumption, high integration level and high reliability is provided for a vehicle suspension system.

Description

Technical Field

[0001] This invention relates to the field of vehicle suspension system technology, and in particular to a self-powered, self-sensing magnetorheological damper. Background Technology

[0002] Magnetorheological dampers are widely used in vehicle suspension systems due to their fast response speed, simple structure, and low power consumption. However, most existing magnetorheological dampers are passive components. First, they cannot be self-powered and usually require an external power supply or the vehicle's main power supply, resulting in complex wiring and high costs. Second, they lack self-sensing capabilities and cannot actively sense their operating status, piston displacement, or temperature, resulting in low levels of intelligence. Third, they rely on external displacement sensors, and existing solutions typically use additional structures such as laser ranging and Hall effect sensors to obtain displacement, increasing cost and structural complexity. Fourth, they lack wireless communication capabilities, meaning information transmission relies on a wired bus, which is not conducive to modular and distributed system deployment.

[0003] Therefore, there is an urgent need in this field for a self-powered, self-sensing magnetorheological damper with high structural integration, self-powered and self-sensing capabilities, the ability to accurately measure absolute displacement and realize wireless or passive data transmission, in order to solve the above problems. Summary of the Invention

[0004] This invention provides a self-powered, self-sensing magnetorheological damper, aiming to solve the problems of existing magnetorheological dampers, such as reliance on external power supply, lack of self-sensing capability, complex structure, cumbersome wiring, and low level of intelligence. It provides an intelligent magnetorheological damper that integrates self-powering, self-sensing, absolute displacement measurement, closed-loop control, and passive communication functions, providing a low-energy-consumption, highly integrated, and highly reliable solution for vehicle suspension intelligent control systems.

[0005] To achieve the above objectives, the present invention provides a self-powered, self-sensing magnetorheological damper, comprising: The damper housing has a magnetorheological chamber inside, in which an excitation coil is installed and filled with magnetorheological fluid; The piston rod is axially movable and is located inside the damper housing; An incremental coil is mounted on the piston rod; A magnetoresistive encoder structure is mounted on the piston rod; A U-shaped magnet is fixedly mounted on the damper housing and arranged opposite to the incremental coil to form a variable magnetic flux system. A magnetoresistive sensor array is fixedly installed inside the damper housing and is used to read the absolute encoding information of the magnetoresistive encoding structure; The rectifier and energy storage module is electrically connected to the incremental coil and is used to rectify, filter, and regulate the alternating voltage generated by the incremental coil into a stable DC voltage and store it. The signal conditioning module is electrically connected to the magnetoresistive sensor array and is used to condition the absolute encoded information and output an absolute displacement signal. The piston head is mounted on the piston rod and located within the magnetorheological chamber.

[0006] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects: 1. This invention utilizes incremental coils and U-shaped magnets arranged on the piston rod to generate induced current by cutting magnetic field lines during the reciprocating motion of the piston. The electrical energy is rectified and regulated by the energy storage module to drive the control module and sensors, thus achieving complete or partial self-powered operation.

[0007] 2. The present invention installs a magnetoresistive coding structure at the lower part of the piston rod and identifies the magnetic field code through a statically arranged magnetic sensitive probe to achieve high-precision absolute displacement measurement, which is used for vehicle height detection and suspension feedback control.

[0008] 3. This invention dynamically changes the damping force by adjusting the viscosity of the magnetorheological fluid with electric current, thereby achieving an adaptive balance between vehicle body stiffness and comfort.

[0009] 4. This invention adopts the principle of magnetic field modulation and utilizes the change in magnetic properties caused by the movement or position of the damper to achieve passive transmission of state parameters without the need for a communication chip or external power supply. Attached Figure Description

[0010] The above and other objects, features and advantages of the present invention will become more apparent from the more detailed description of exemplary embodiments of the invention in conjunction with the accompanying drawings, wherein like reference numerals generally denote like parts.

[0011] Figure 1 This is a schematic diagram of the structure of the self-powered, self-sensing magnetorheological damper provided in this embodiment; Figure 2 This is an exploded view of the piston rod provided in this embodiment; Figure 3 This is a schematic diagram of the topology of the self-powered process provided in this embodiment; Figure 4 This is a schematic diagram of the 8-bit absolute magnetic coding structure provided in this embodiment; Figure 5 This is a schematic diagram of the structure for absolute displacement measurement provided in this embodiment.

[0012] In the diagram, 1. Piston rod; 2. Incremental coil; 3. Magnetoresistive encoder structure; 4. U-shaped magnet; 5. Top cover; 6. Magnetoresistive sensor array; 7. Rectification and energy storage module; 8. Signal conditioning module; 9. Damper housing; 10. Piston head; 11. Magnetorheological chamber; 12. Flexible diaphragm; 13. Compensating air chamber; 14. Bottom mounting base. Detailed Implementation

[0013] 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. 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.

[0014] Example 1: Please refer to Figure 1-5 A self-powered, self-sensing magnetorheological damper, comprising: The damper housing 9 has a magnetorheological chamber 11 inside, and an excitation coil is installed in the magnetorheological chamber 11 and filled with magnetorheological fluid. The piston rod 1 is axially movable and is disposed within the damper housing 9; Incremental coil 2 is mounted on the piston rod 1; The magnetoresistive encoder structure 3 is mounted on the piston rod 1; U-shaped magnet 4 is fixedly mounted on the damper housing 9 and arranged opposite to the incremental coil 2 to form a variable magnetic flux system; A magnetoresistive sensor array 6 is fixedly installed inside the damper housing 9 and is used to read the absolute encoding information of the magnetoresistive encoding structure 3; The rectifier and energy storage module 7 is electrically connected to the incremental coil 2 and is used to rectify, filter, and regulate the alternating voltage generated by the incremental coil 2 into a stable DC voltage and store it. The signal conditioning module 8 is electrically connected to the magnetoresistive sensor array 6 and is used to condition the absolute encoded information and output an absolute displacement signal. The piston head 10 is disposed on the piston rod 1 and located inside the magnetorheological chamber 11.

[0015] Specifically, the damper housing 9 is made of a high-permeability soft magnetic material (such as low-carbon steel or silicon steel sheet), serving as a closed magnetic circuit channel for the excitation magnetic field. This allows the magnetic field generated by the excitation coil to form a complete magnetic circuit through the housing, acting on the magnetorheological fluid. The piston rod 1 can reciprocate along the axial direction of the damper housing 9, providing a mounting carrier for the incremental coil 2, the magnetorheological coding structure 3, and the piston head 10. The incremental coil 2, in conjunction with the U-shaped magnet 4, generates electromagnetic induction through relative motion to achieve energy harvesting. The magnetorheological coding structure 3, in conjunction with the magnetorheological sensor array 6, achieves absolute displacement measurement. The rectification and energy storage module 7 processes the induced electrical energy and supplies power to various power-consuming modules. The signal conditioning module 8 processes the output signal of the magnetorheological sensor array 6. The magnetorheological fluid in the magnetorheological chamber 11 changes its viscosity under the action of the magnetic field, working with the piston head 10 to adjust the damping force.

[0016] In one implementation, please refer to Figure 2-3 The incremental coil 2 is embedded in the surface of the piston rod 1 and moves axially back and forth together with the piston rod 1; an electromagnetic shielding layer is provided between the incremental coil 2 and the magnetoresistive encoding structure 3.

[0017] Specifically, the electromagnetic shielding layer is made of nanocrystalline soft magnetic alloy with a thickness of 0.3mm to 0.8mm. An incremental coil 2 is installed on the outer surface of the piston rod 1 and works in conjunction with the U-shaped magnet 4. During the reciprocating motion of the piston, it cuts the magnetic field lines to generate an induced voltage. After rectification, filtering, and voltage stabilization, a stable DC output is formed, achieving self-powered operation. Alternatively, the incremental coil 2 can be wound on a non-magnetic frame and installed on the piston rod 1. When it moves with the piston rod 1, it passes through or approaches the U-shaped magnet 4 and generates an induced current through an electromagnetic induction mechanism. The electromagnetic shielding layer is used to suppress the electromagnetic field generated by the incremental coil 2 during power generation from interfering with the magnetic signal of the magnetoresistive coding structure 3, ensuring the stability of the self-sensing function. At the same time, the nanocrystalline soft magnetic alloy has excellent magnetic shielding performance. This thickness range can ensure the shielding effect without affecting the structural compactness and strength of the piston rod 1, effectively isolating the electromagnetic interference between the incremental coil 2 and the magnetoresistive coding structure 3.

[0018] In one implementation, please refer to Figure 4-5 The magnetoresistive coding structure 3 is an 8-bit absolute magnetic coding structure set on the surface of the piston rod 1, using Gray code encoding. The magnetoresistive sensor array 6 includes 8 sets of magnetoresistive sensors arranged along the axial direction, used to read the absolute coding information of the 8-bit magnetic coding structure and output absolute displacement signals.

[0019] Specifically, the magnetoresistive coding structure 3 is a coding magnetic ring arranged on the axial surface of the piston rod 1, containing 8 bit coding areas. Each bit code represents a magnetic pole or a permeability change unit. Each coding bit is represented by a "high permeability segment" and a "low permeability segment" to represent "1" and "0" respectively, which can represent up to 256 unique positions. The coding structure is prepared by laser ablation magnetic powder spraying, permanent magnet array, or composite material embedding, which has high consistency and durability. The 8 sets of magnetoresistive sensors are AMR, GMR, or TMR sensors, which are arranged parallel to each other along the axial direction on the damper housing 9 or the inner wall of the sleeve corresponding to the coding area. Each set of sensors reads a magnetic bit, and the combination forms an 8-bit binary signal. The sensor output is amplified and converted from analog to digital before being input to the microcontroller for decoding. The absolute axial displacement of the piston can be obtained without resetting or referencing the starting point, with a resolution of millimeters. The current position information can still be maintained after power failure or restart, without the need for zeroing operation.

[0020] In one embodiment, the U-shaped magnet 4 is embedded in the reserved slot of the upper end cover 5 of the damper housing 9 and is sealed and fixed by epoxy resin.

[0021] Specifically, the U-shaped magnet 4 uses high-temperature resistant permanent magnet materials, including neodymium iron boron or samarium cobalt, with a working temperature tolerance range covering -40℃ to +200℃. It is symmetrically fixed on the upper end cover 5 and works with the incremental coil 2 to form a variable magnetic flux system, ensuring that the piston rod 1 can generate a stable magnetic flux change when it moves to achieve efficient energy harvesting.

[0022] In one embodiment, the rectification and energy storage module 7 includes a rectifier circuit, an energy storage capacitor, and a voltage regulation chip, used to convert the AC voltage induced by the incremental coil 2 into a DC voltage and to power the signal conditioning module 8 and the magnetoresistive sensor array 6.

[0023] Specifically, the rectifier and energy storage module 7 is directly integrated into the internal structure of the magnetorheological damper. The induced AC voltage is rectified by the rectifier circuit and filtered by the filter circuit to be converted into DC voltage. Then, the voltage is regulated by the voltage regulation chip, which can provide standard voltage outputs such as 3.3V and 5V according to system requirements, providing stable power support for the internal control system (such as magnetorheological fluid control, signal processing, communication, etc.) without the need for external power supply or wiring. This structure generates electrical energy through the natural movement of the piston without adding additional actuation mechanisms, which greatly improves the system's encapsulation, reliability and intelligence level. Compared with traditional magnetorheological dampers that require external power cables or control units, it has higher structural integration and layout flexibility. In scenarios such as intelligent vehicles, unmanned systems, and bridge structures, it has the advantages of adaptive, low power consumption and long life operation.

[0024] In one embodiment, the damper housing 9 is further provided with a compensation air chamber 13, which is isolated from the magnetorheological chamber 11 by a flexible diaphragm 12, and is filled with thermal expansion compensation fluid.

[0025] Specifically, the flexible diaphragm 12 has a fluororubber-Kevlar composite layer structure with a thickness of 0.5 mm and its edges are sealed by laser welding. The thermal expansion compensation fluid is a silicon-based thermal expansion compensation fluid with an operating temperature range of -40℃ to +150℃. When the magnetorheological fluid expands in volume due to temperature changes, the flexible diaphragm 12 is compressed and deformed to absorb the excess volume. When the temperature decreases, the diaphragm rebounds to fill the volume gap in the main cavity, maintaining stable pressure in the cavity and preventing the damper's performance from being affected by changes in the volume of the magnetorheological fluid. At the same time, the fluororubber-Kevlar composite layer structure has high pressure resistance and good sealing performance. The laser welding sealing method ensures the sealing of the connection between the flexible diaphragm 12 and the cavity, preventing the magnetorheological fluid and the thermal expansion compensation fluid from penetrating each other. It also ensures that the diaphragm can deform flexibly under temperature changes and pressure fluctuations to achieve the volume compensation function.

[0026] In one embodiment, the system further includes an embedded controller that receives an absolute displacement signal output by a signal conditioning module and adjusts the current of the excitation coil in the magnetorheological chamber 11 according to the signal, thereby changing the shear force of the magnetorheological fluid in the magnetorheological chamber 11 and achieving adaptive damping control.

[0027] Specifically, the embedded controller is an MCU or FPGA. Relying on the internally acquired absolute displacement signal and power supply system, it calculates the damping target value according to the displacement change law and the vehicle's motion state. By adjusting the magnetorheological coil current through the drive module, it changes the shear force of the magnetorheological fluid in the magnetorheological chamber 11, thereby achieving continuously adjustable damping output. It can achieve local response without an external main control system and is suitable for complex systems such as electric vehicles, autonomous driving platforms, and unmanned transportation equipment.

[0028] In one embodiment, the incremental coil 2 and the magnetoresistive coding structure 3 constitute a magnetic circuit system, which realizes passive wireless communication with the external control system through magnetic flux modulation to transmit damper status information.

[0029] Specifically, when piston rod 1 moves, incremental coil 2 cuts the magnetic field to form an alternating magnetic flux. This, combined with magnetoresistive coding structure 3, forms a magnetic field modulation signal with position coding. By modulating the characteristic parameters of this magnetic flux (such as amplitude, frequency, pulse interval, etc.), a digital code representing the damper's state can be embedded into the magnetic signal, forming a magnetic field data transmission channel. This eliminates the need for an external power supply or wireless communication module, enabling passive remote transmission of critical data. It is suitable for low-power, difficult-to-wire, or high-reliability scenarios. This passive wireless communication requires no power supply module and utilizes the structure's own magnetic properties and changes generated by motion to complete data communication. It can be used in edge node systems, such as intelligent vibration damping control, suspension status recognition, rail vehicles, or special equipment. It achieves "plug and play," reducing vehicle wiring and maintenance costs. It can complement existing magnetoresistive coding systems and incremental coil systems, further enhancing signal integrity. It does not rely on traditional antenna communication devices or wireless modules. It uses "magnetic flux modulation" as the data transmission medium. It is suitable for high-reliability or space-constrained environments. It provides a new path for the development of magnetorheological dampers from "functional components" to "information-sensing passive communication components."

[0030] In one embodiment, a bottom mounting base 14 is also included, which is connected to the vehicle chassis or axle, for fixing one end of the damper, providing structural support and an installation interface.

[0031] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A self-powered, self-sensing magnetorheological damper, characterized in that, include: The damper housing (9) has a magnetorheological chamber (11) inside, and an excitation coil is provided in the magnetorheological chamber (11) and filled with magnetorheological fluid. The piston rod (1) is axially movable and is disposed inside the damper housing (9); An incremental coil (2) is mounted on the piston rod (1); A magnetoresistive encoding structure (3) is mounted on the piston rod (1); U-shaped magnet (4) is fixedly mounted on the damper housing (9) and arranged opposite to the incremental coil (2) to form a variable magnetic flux system; A magnetoresistive sensor array (6) is fixedly installed inside the damper housing (9) and is used to read the absolute encoding information of the magnetoresistive encoding structure (3); The rectifier and energy storage module (7) is electrically connected to the incremental coil (2) and is used to rectify, filter, and regulate the alternating voltage generated by the incremental coil (2) into a stable DC voltage and store it. The signal conditioning module (8) is electrically connected to the magnetoresistive sensor array (6) and is used to condition the absolute coded information and output an absolute displacement signal. The piston head (10) is disposed on the piston rod (1) and located in the magnetorheological chamber (11).

2. The self-powered, self-sensing magnetorheological damper according to claim 1, characterized in that, The incremental coil (2) is embedded in the surface of the piston rod (1) and moves axially back and forth together with the piston rod (1); an electromagnetic shielding layer is provided between the incremental coil (2) and the magnetoresistive coding structure (3).

3. The self-powered, self-sensing magnetorheological damper according to claim 2, characterized in that, The electromagnetic shielding layer is made of nanocrystalline soft magnetic alloy with a thickness of 0.3 mm to 0.8 mm.

4. The self-powered, self-sensing magnetorheological damper according to claim 1, characterized in that, The magnetoresistive coding structure (3) is an 8-bit absolute magnetic coding structure set on the surface of the piston rod (1) and adopts Gray code coding method; the magnetoresistive sensor array (6) includes 8 sets of magnetoresistive sensors arranged along the axial direction of the piston rod (1) for reading the absolute coding information of the 8-bit magnetic coding structure and outputting absolute displacement signal.

5. The self-powered, self-sensing magnetorheological damper according to claim 1, characterized in that, The U-shaped magnet (4) is embedded in the reserved slot of the upper end cover (5) of the damper housing (9) and is sealed and fixed by epoxy resin.

6. The self-powered, self-sensing magnetorheological damper according to claim 1, characterized in that, The rectification and energy storage module (7) includes a rectifier circuit, an energy storage capacitor and a voltage regulation chip, used to convert the AC voltage induced by the incremental coil (2) into DC voltage and to power the signal conditioning module (8) and the magnetoresistive sensor array (6).

7. The self-powered, self-sensing magnetorheological damper according to claim 1, characterized in that, The damper housing (9) is also provided with a compensation air chamber (13), which is isolated from the magnetorheological chamber (11) by a flexible diaphragm (12), and is filled with thermal expansion compensation fluid.

8. The self-powered, self-sensing magnetorheological damper according to claim 7, characterized in that, The flexible diaphragm (12) has a fluororubber-Kevlar composite layer structure with a thickness of 0.5 mm and its edges are sealed by laser welding.

9. The self-powered, self-sensing magnetorheological damper according to claim 1, characterized in that, It also includes an embedded controller, which receives the absolute displacement signal output by the signal conditioning module (8) and adjusts the current of the excitation coil in the magnetorheological chamber (11) according to the absolute displacement signal, thereby changing the shear force of the magnetorheological fluid in the magnetorheological chamber (11).

10. The self-powered, self-sensing magnetorheological damper according to claim 1, characterized in that, The incremental coil (2) and the magnetoresistive coding structure (3) constitute a magnetic circuit system, which realizes passive wireless communication with the external control system through magnetic flux modulation and is used to transmit damper status information.

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