Low-temperature preheating magnetorheological damper

Abstract

The utility model provides a low-temperature preheating magnetorheological damper. The magnetorheological damper comprises a magnetorheological damper body and a heating unit. The heating unit comprises any one or more of the following conditions: A) the heating unit comprises an induction heating power supply, a wire and a magnet exciting coil. And B) the heating unit comprises an induction heating power supply, a lead and an external coil. And (C) the heating unit comprises a temperature control power supply, a lead and a heating element. And D) the heating unit comprises a temperature control power supply, a lead and a heating element. According to the low-temperature preheating magnetorheological damper, the natural convection effect of magnetorheological fluid and the influence of viscosity change are comprehensively considered, and the heat conduction efficiency is improved by regulating and controlling the current frequency and the duty ratio in real time. The four heating schemes do not conflict with one another and can be combined for use. Induction heating control strategies may be used in damper induction heating scenarios to improve heat transfer efficiency.

Description

Technical Field

[0001] This utility model relates to the field of magnetorheological damper technology, and in particular to a low-temperature preheating magnetorheological damper. Background Technology

[0002] Magnetorheological dampers, as the core actuators of vehicle electromagnetic suspension systems, achieve millisecond-level phase transitions from liquid to solid state through magnetic field control. Their magnetically controlled shear yield stress endows the system with controllable damping characteristics. This technology significantly improves vehicle handling stability, ride comfort, and safety thanks to its precise control capabilities and rapid response, while also offering engineering advantages such as low power consumption and a wide dynamic range.

[0003] However, performance degradation at low temperatures severely restricts its practical application: when the temperature drops below -20°C, the zero-field viscosity of magnetorheological fluids can increase significantly, fluidity decreases, and damping characteristics are sharply reduced, exhibiting near-rigid characteristics. Taking automotive applications as an example, the rheological properties of magnetorheological fluids change significantly in winter environments, exhibiting a sharp increase in viscoelasticity. Coupled with random vibration loads from icy and snowy roads, the system faces the dual challenges of dynamic response hysteresis and damping force output instability. Existing research on solutions mainly focuses on performance degradation at high temperatures, while low-temperature solutions are limited. The main technical routes include optimizing the composition of magnetorheological fluids and mechanically excited heating, but both have limitations: material modification techniques are complex, costly, and prone to weakening other properties; mechanically excited heating relies on the dissipation of vibration energy into heat energy, but its heating efficiency is insufficient in static or low-amplitude vibration scenarios, making it difficult to meet the rapid start-up requirements in low-temperature environments.

[0004] Therefore, developing a low-temperature preheating magnetorheological damper is of great significance. Utility Model Content

[0005] The purpose of this invention is to provide a low-temperature preheating magnetorheological damper to solve the problems existing in the prior art.

[0006] The technical solution adopted to achieve the purpose of this utility model is as follows: a low-temperature preheating magnetorheological damper, comprising a magnetorheological damper body and a heating unit.

[0007] The magnetorheological damper body includes a piston assembly, a cylinder, an excitation coil, and a floating piston. The piston assembly is slidably fitted inside the cylinder. The piston assembly includes a piston head and a piston rod. The piston rod has a lead wire channel along its axial direction. The piston head has a coil groove. An excitation coil is wound inside the coil groove. A split guide is provided on the radially outer surface of the piston head. The outer contour of the split guide has multiple guide portions spaced circumferentially. The guide portions contact the inner wall of the cylinder. A damping channel is formed between two adjacent guide portions. The floating piston is slidably fitted between the cylinder bottom and the piston assembly. The floating piston divides the cylinder into a gas chamber and a damping chamber. The damping chamber is filled with magnetorheological fluid.

[0008] The heating unit includes any one or more of the following conditions:

[0009] A) The heating unit includes an induction heating power supply, wires, and an excitation coil. The wires are introduced through a lead channel, connecting the induction heating power supply and the excitation coil.

[0010] B) The heating unit includes an induction heating power supply, wires, and an external coil. The external coil is wrapped around the outer wall of the cylinder. The wires connect the induction heating power supply and the external coil.

[0011] C) The heating unit includes a temperature control power supply, wires, and a heating element. The heating element is attached to the outer wall of the cylinder. The wires connect the temperature control power supply and the heating element.

[0012] D) The heating unit includes a temperature control power supply, wires, and a heating element. The heating element is integrated inside the piston rod or piston head. The wires connect the temperature control power supply and the heating element.

[0013] Furthermore, the induction heating power supply is selected from AC power or pulse modulation power.

[0014] Furthermore, the AC power supply includes a signal generator, a power amplifier, and a DC power supply. The output terminal of the signal generator is connected to the signal input terminal of the power amplifier. The positive and negative terminals of the DC power supply are connected to the DC input port of the power amplifier. The output terminal of the power amplifier is connected to an excitation coil or an external coil.

[0015] Furthermore, the temperature control power supply is selected from DC power supplies or AC power supplies.

[0016] Furthermore, it also includes one or more temperature sensors. The temperature sensors are arranged on the outer cylinder wall or inside the piston head.

[0017] Furthermore, the heating element is selected from thermal resistance wires.

[0018] Furthermore, a buffer ring is provided on the top of the cylinder.

[0019] Furthermore, the cylinder barrel is made of stainless steel or titanium alloy.

[0020] Furthermore, a low-temperature preheating magnetorheological damper is applied in automobiles. The vehicle's existing 12V / 48V DC power bus is used as the power source.

[0021] The technical effects of this utility model are beyond doubt:

[0022] Taking automotive magnetorheological dampers as an example, preheating the magnetorheological damper before starting the car in low winter temperatures (when the damper does not need to provide vibration reduction) can quickly restore its working efficiency, solving the problem of functional degradation or failure of magnetorheological dampers at low temperatures.

[0023] A. An external induction heating method is used to electromagnetically induction heat the metal cylinder of the damper, thereby preheating the internal magnetorheological fluid. This method has high thermal efficiency, fast heating rate, and can be easily superimposed and adapted to existing magnetorheological dampers.

[0024] B. When using the existing built-in excitation coil for induction heating, no structural changes are required. It can be directly applied to existing magnetorheological dampers without increasing costs.

[0025] C. Taking into account the natural convection effect and viscosity change of magnetorheological fluid: improve heat transfer efficiency by real-time adjustment of current frequency and duty cycle;

[0026] D. The four heating methods do not conflict with each other and can be used in combination. Attached Figure Description

[0027] Figure 1 A schematic diagram of the magnetorheological damper body;

[0028] Figure 2 Schematic diagram of induction (eddy current) heating of excitation coil;

[0029] Figure 3 Schematic diagram of external coil induction (eddy current) heating;

[0030] Figure 4 This is a schematic diagram of an external heating element;

[0031] Figure 5 This is a schematic diagram of the built-in heating element.

[0032] In the diagram: Piston assembly 1, cylinder 2, excitation coil 3, floating piston 4, damping channel 5, gas chamber 6, magnetorheological fluid 7, external coil 8, heating element 9, signal generator 10, power amplifier 11, DC power supply 12, buffer ring 13, temperature sensor 14. Detailed Implementation

[0033] The present invention will be further described below with reference to embodiments, but it should not be construed as limiting the scope of the present invention to the following embodiments. Various substitutions and modifications made based on ordinary technical knowledge and conventional methods in the art without departing from the above-described technical concept of the present invention should be included within the protection scope of the present invention.

[0034] Example 1:

[0035] See Figures 1-4 This embodiment provides a low-temperature preheating magnetorheological damper, including a magnetorheological damper body and a heating unit.

[0036] The magnetorheological damper body includes a piston assembly 1, a cylinder 2, an excitation coil 3, and a floating piston 4. The piston assembly is slidably fitted inside the cylinder 2. The piston assembly includes a piston head and a piston rod. The piston rod has a lead wire channel along its axial direction. The piston head has a coil groove. The excitation coil 3 is wound inside the coil groove. A split guide is provided on the radial outer surface of the piston head. The outer contour of the split guide has multiple guide portions spaced circumferentially. The guide portions contact the inner wall of the cylinder 2. A damping channel 5 is formed between two adjacent guide portions. The floating piston 4 is slidably fitted between the bottom of the cylinder 2 and the piston assembly 1. The floating piston 4 divides the cylinder 2 into a gas chamber 6 and a damping cavity. The damping cavity is filled with magnetorheological fluid 7.

[0037] The heating unit includes any one or more of the following conditions:

[0038] A) The heating unit includes an induction heating power supply, wires, and an excitation coil 3. The wires are introduced through a lead channel, connecting the induction heating power supply and the excitation coil 3. This heating scheme fully utilizes the existing piston excitation coil structure inside the magnetorheological damper, achieving induction heating by applying alternating current to it. When the alternating current passes through the coil, an alternating magnetic field is generated inside the metal piston head. Under the action of the alternating magnetic field, the damper piston head generates eddy current losses and hysteresis losses, converting electrical energy into heat energy. Through solid-liquid heat transfer, the surrounding magnetorheological fluid is preheated. This scheme does not require modification of the damper and has advantages such as simple structure and low cost.

[0039] B) The heating unit includes an induction heating power supply, wires, and an external coil 8. The external coil 8 is wrapped around the outer wall of the cylinder 2. The wires connect the induction heating power supply and the external coil 8. The outer cylinder of the magnetorheological damper is generally made of metal and contains the magnetorheological fluid and other necessary structures. An electromagnetic coil is wrapped around the outside of the magnetorheological damper. When an alternating current of a certain frequency and current intensity is applied to it, the alternating magnetic field generated by the external electromagnetic coil will induce a current in the metal outer cylinder of the magnetorheological damper, which is converted into heat energy due to the internal resistance of the metal. This heat energy is then used to heat the internal magnetorheological fluid through solid-liquid heat conduction. Compared with Scheme 1, this scheme has a larger coil layout space and a faster heating speed, which can more quickly raise the temperature of the magnetorheological fluid.

[0040] C) The heating unit includes a temperature control power supply, wires, and a heating element 9. The heating element 9 is attached to the outer wall of the cylinder 2. The wires connect the temperature control power supply and the heating element 9. This scheme uses an integrated heating element outside the magnetorheological damper for heating; in the experiment, a thermal resistance wire was selected as the heating element. When current flows through the thermal resistance wire, heat is generated, and the heat is transferred to the internal magnetorheological fluid through the damper's metal outer cylinder via thermal conduction. This scheme allows for flexible adjustment of the type, layout, and power of the heating element according to actual needs to meet heating requirements under different operating conditions.

[0041] D) The heating unit includes a temperature control power supply, wires, and a heating element 9. The heating element 9 is built into the piston head and piston rod of the piston assembly 1. The wires connect the temperature control power supply and the heating element 9. This scheme uses a heating element integrated inside the magnetorheological damper for heating. In the experiment, an insulated thermal resistance wire was selected as the heating element. When current flows through the thermal resistance wire, heat is generated, and the heat is transferred to the internal magnetorheological fluid through the damper piston via thermal conduction to achieve heating. This scheme can flexibly adjust the type, layout, and power of the heating element according to actual needs to meet the heating requirements under different working conditions.

[0042] Example 2:

[0043] The main content of this embodiment is the same as that of embodiment 1, except that the induction heating power supply is selected as an AC power supply or a pulse modulation power supply.

[0044] Example 3:

[0045] This embodiment is similar in main content to Embodiment 2, except that the AC power supply includes a signal generator 10, a power amplifier 11, and a DC power supply 12. The output terminal of the signal generator 10 is connected to the signal input terminal of the power amplifier 11. The positive and negative terminals of the DC power supply 12 are connected to the DC input port of the power amplifier 11. The output terminal of the power amplifier 11 is connected to the excitation coil 3, the external coil 8, and / or the heating element 9. The signal generator 10 is responsible for generating a high-frequency AC signal, defining the heating frequency and waveform. The power amplifier 11 receives the weak signal from the signal generator 10 and amplifies it to the power level required to drive the heating unit. The excitation coil 3, the external coil 8, or the heating element 9, acting as a load, receives the high-frequency, high-current output from the power amplifier 11, generating an alternating magnetic field, and achieving heating through electromagnetic induction. The DC power supply 12 provides a stable DC input to the power amplifier 11.

[0046] Example 4:

[0047] The main content of this embodiment is the same as that of embodiment 1, except that the temperature control power supply is selected from DC power supply or AC power supply.

[0048] Example 5:

[0049] The main content of this embodiment is the same as that of embodiment 1, wherein a buffer ring 13 is provided on the top of the cylinder 2.

[0050] Example 6:

[0051] The main content of this embodiment is the same as that of embodiment 1 or 2, wherein the heating element 9 is a thermal resistance wire.

[0052] Example 7:

[0053] The main content of this embodiment is the same as that of embodiments 1 to 3, wherein the material of the cylinder 2 is stainless steel or titanium alloy.

[0054] Example 8:

[0055] The main content of this embodiment is the same as any one of embodiments 1 to 4, and it also includes one or more temperature sensors, taking the NTC thin-film temperature sensor 14 as an example. The NTC thin-film temperature sensor 14 is arranged at different positions on the outer cylinder, with the two ends and the middle corresponding to the position of the internal magnetorheological fluid being preferred positions, or it can be installed at different positions on the piston rod assembly, with the piston rod end and the inside of the piston head being preferred positions.

[0056] Example 9:

[0057] This embodiment verifies the effectiveness of the excitation coil 3 in performing the heating function. It is based on a commercially available magnetorheological damper with a rated current of 0–1.5A. A DC regulated power supply provides a stable and adjustable DC voltage for the entire experimental system, meeting the power requirements under different experimental conditions. A signal generator generates PWM signals of different frequencies and duty cycles to provide control signals to the induction heating drive module, enabling frequency adjustment of the magnetorheological damper's induction heating. The induction heating drive module converts the signal output from the signal generator into the alternating magnetic field required for induction heating. A thermocouple thermometer monitors the temperature change of the magnetorheological damper in real time during the experiment using thermocouple sensors and transmits the data to a host computer for recording and analysis. The host computer system is used for the acquisition, storage, and analysis of experimental data.

[0058]

[0059] Experimental results show that the piston excitation coil induction heating scheme can raise the temperature of the core working area of ​​the damper by 22.6℃ within 300 seconds without changing the existing structure, effectively achieving the expected magnetically controlled damping performance compared to the unheated condition. This technology provides a new and feasible approach to solving the performance degradation problem of magnetorheological dampers in low-temperature environments.

[0060] Example 7:

[0061] This embodiment provides an application of the induction-heated preheated magnetorheological damper according to any one of embodiments 1 to 5, specifically an automotive magnetorheological suspension damper. The hardware configuration is as follows:

[0062] Onboard power system: The vehicle’s original 12V / 48V DC power bus is used as the power source, and the adjustable voltage conversion module provides a regulated power supply to the induction heating system; the battery SOC (state of charge) is monitored in real time, and when SOC < 30%, it automatically switches to low power mode (heating power ≤ 200W).

[0063] Induction heating drive module: a high-frequency inverter directly connected to the damper piston coil, with a built-in high-power IGBT module (withstanding voltage 600V, peak current 50A); it is compatible with the vehicle CAN FD bus protocol and receives heating commands (including parameters such as target temperature and heating rate) sent by the body domain controller (BDC).

[0064] Temperature monitoring system: NTC thin film temperature sensors (accuracy ±0.5℃, response time <100ms) are embedded in key locations of the damper working chamber (piston rod end, outer cylinder middle); the sensor signals are transmitted to the chassis domain controller (CDC) via LIN bus to achieve data interaction with the vehicle thermal management system.

[0065] Control unit integration: The vehicle's original electronic control unit (ECU) is reused, and a new induction heating control firmware module is added to achieve dynamic frequency-duty cycle optimization (control parameters are updated every 50ms).

Claims

1. A cryogenic pre-heat magneto-rheological damper, characterized by: Includes the magnetorheological damper body and the heating unit; The magnetorheological damper body includes a piston assembly (1), a cylinder (2), an excitation coil (3), and a floating piston (4); the piston assembly is slidably disposed within the cylinder (2); the piston assembly includes a piston head and a piston rod; the piston rod is provided with a lead wire channel along the axial direction; the piston head is provided with a coil groove; the excitation coil (3) is wound in the coil groove; the radial outer surface of the piston head is provided with a split guide; the outer contour of the split guide is provided with multiple guide portions spaced apart along its circumference; the guide portions contact the inner wall of the cylinder (2); a damping channel (5) is formed between two adjacent guide portions; the floating piston (4) is slidably disposed between the bottom of the cylinder (2) and the piston assembly (1); the floating piston (4) divides the cylinder (2) into a gas chamber (6) and a damping cavity; the damping cavity is filled with magnetorheological fluid (7). The heating unit includes any one or more of the following conditions: A) The heating unit includes an induction heating power supply, wires and an excitation coil (3); the wires are introduced through a lead-in channel and connect the induction heating power supply and the excitation coil (3). B) The heating unit includes an induction heating power supply, wires and an external coil (8); the external coil (8) is wrapped around the outer wall of the cylinder (2); the wires connect the induction heating power supply and the external coil (8). C) The heating unit includes a temperature control power supply, wires and a heating element (9); the heating element (9) is attached to the outer wall of the cylinder (2); the wires connect the temperature control power supply and the heating element (9). D) The heating unit includes a temperature control power supply, wires and a heating element (9); the heating element (9) is integrated inside the piston rod or piston head; the wires connect the temperature control power supply and the heating element (9).

2. The cryogenic pre-heat MR damper of claim 1, wherein: The induction heating power supply is selected from AC power or pulse modulation power.

3. The cryogenic pre-heat MR damper of claim 2, wherein: The AC power supply includes a signal generator (10), a power amplifier (11), and a DC power supply (12); the output terminal of the signal generator (10) is connected to the signal input terminal of the power amplifier (11); the positive and negative terminals of the DC power supply (12) are connected to the DC input port of the power amplifier (11); the output terminal of the power amplifier (11) is connected to the excitation coil (3) or the external coil (8).

4. The cryogenic pre-heat MR damper of claim 1, wherein: The temperature control power supply can be either a DC power supply or an AC power supply.

5. The cryogenic pre-heat MR damper of claim 1, wherein: It also includes one or more temperature sensors (14); the temperature sensors (14) are arranged on the outer cylinder wall or inside the piston head.

6. The cryogenic pre-heat MR damper of claim 1, wherein: The heating element (9) is made of thermal resistance wire.

7. The cryogenic pre-heat MR damper of claim 1, wherein: The cylinder (2) is provided with a buffer ring (13) on the top of the cylinder.

8. A low-temperature preheating magnetorheological damper according to claim 1, characterized in that: The cylinder (2) is made of stainless steel or titanium alloy.

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