Magnetorheological damper with frequency-dependent damping and nonlinear stiffness characteristics

Abstract

The application discloses a magneto-rheological damper with frequency-variable damping and nonlinear stiffness characteristics, wherein a main cylinder assembly comprises a main cylinder body and a piston member, the piston member comprises a piston cylinder, a permanent magnet and a floating spring, the piston cylinder is coaxially and slidably arranged in the main cylinder body, the permanent magnet is slidably arranged in the piston cylinder, and the floating spring is arranged in the piston cylinder and exerts an elastic force on the permanent magnet in the axial direction; a secondary cylinder assembly comprises a secondary cylinder body and a plurality of stiffness springs, the secondary cylinder body is coaxially arranged with the main cylinder body, and the stiffness springs are arranged in the secondary cylinder body in a following mode. The damper provided by the application can respond to vibration excitations with different frequencies and amplitudes, can provide large damping and large stiffness when the vibration excitation is low frequency and large amplitude, and can provide small damping and small stiffness when the vibration excitation is high frequency and small amplitude, so that good damping stiffness matching characteristics can be obtained in a wide frequency range, and the overall damping performance of the system is significantly improved.

Description

Technical Field

[0001] The invention belongs to the technical field of vibration dampers and relates to a magnetorheological vibration damper with frequency-varying damping and nonlinear stiffness characteristics. Background Art

[0002] Magnetorheological dampers, intelligent vibration reduction devices that utilize the magnetorheological effect to alter fluid properties and, in turn, the damping characteristics of the damper, have recently gained widespread application in wide-band vibration reduction applications, such as vehicle suspension systems, precision machinery platforms, aerospace, and bridges. Traditional magnetorheological dampers use an externally input current to generate a magnetic field, controlling the rheological properties of the magnetorheological fluid and thereby adjusting the damping force of the damper.

[0003] Complex mechanical systems are subject to widely varying vibration excitations during different operating phases (e.g., an engine experiences low-frequency, high-amplitude vibrations during startup, and high-frequency, small-amplitude vibrations during steady-state operation). Failure to effectively dampen these vibrations can lead to decreased system efficiency or even failure. Current magnetorheological dampers primarily achieve effective vibration damping through external, controllable current input, and their stiffness generally varies linearly. If the electronic control system malfunctions during operation, the damper will instantly fail, a significant disadvantage for mechanical equipment operating in complex and harsh environments.

[0004] To solve the above problems, a new type of passive magnetorheological vibration damper is needed to reduce the dependence on the electronic control system and improve the adaptability and reliability in wide-band complex vibration situations. Summary of the Invention

[0005] In view of this, the present invention provides a magnetorheological shock absorber with frequency-variable damping and nonlinear stiffness characteristics. By arranging a floating spring at the end of the permanent magnet, the entire piston component can resonate with the resonance of the external excitation, thereby providing a larger magnetic field for the effective damping gap and improving the damping force; the setting of the stiffness spring can provide small stiffness when the stroke of the piston component is small, and improve its stiffness when the stroke increases, so that the entire shock absorber can respond to vibration excitations of different frequencies and amplitudes, and provide large damping and large stiffness at low frequencies and large amplitudes, and provide small damping and small stiffness at high frequencies and small amplitudes, so that good damping and stiffness matching characteristics can be obtained within a wide frequency band, significantly improving the overall vibration reduction performance of the system.

[0006] The present invention discloses a magnetorheological vibration absorber with frequency-dependent damping and nonlinear stiffness characteristics, comprising:

[0007] A master cylinder assembly, comprising a master cylinder body and a piston member, wherein the piston member comprises a piston barrel, a permanent magnet, and a floating spring, wherein the piston barrel is coaxially and drivably slidably disposed in the master cylinder body, the permanent magnet is drivably slidably disposed in the piston barrel, and the floating spring is installed in the piston barrel, wherein the elastic force of the floating spring acts axially on the permanent magnet;

[0008] The auxiliary cylinder assembly includes an auxiliary cylinder body and multiple stiffness springs. The auxiliary cylinder body is interconnected with the main cylinder body and is coaxially arranged. Multiple stiffness springs are arranged in the auxiliary cylinder body in sequence along the axial direction. Any of the stiffness springs is driven to be compressed or stretched synchronously with the sliding of the piston cylinder.

[0009] Furthermore, it also includes a variable gap component, which includes a left variable gap cylinder and a right variable gap cylinder. The inner wall surfaces of the left variable gap cylinder and the right variable gap cylinder are conical structures whose diameters gradually increase along the radial direction. The left variable gap cylinder and the right variable gap cylinder are respectively installed on the left and right ends of the main cylinder body with the end with a larger diameter facing the main cylinder body. The auxiliary cylinder body is connected to the main cylinder body through the left variable gap cylinder. The auxiliary cylinder body, the left variable gap cylinder, the main cylinder body and the right variable gap cylinder constitute the damper cylinder.

[0010] Furthermore, the stiffness spring is a conical helical structure, and any adjacent stiffness springs are arranged opposite to each other.

[0011] Furthermore, it also includes a piston rod assembly, which includes a main piston rod and a secondary piston rod. The main piston rod has a first end and a second end in the axial direction. The first end of the main piston rod is located outside the damper cylinder, and the second end of the main piston rod extends axially into the main cylinder body. The main piston rod is inserted into the piston member, and the secondary piston rod is installed on the second end of the main piston rod, and the end of the secondary piston rod extends axially into the secondary cylinder body.

[0012] Furthermore, the auxiliary cylinder assembly further includes a limiting ring, which is mounted on the auxiliary cylinder body and sleeved on the auxiliary piston rod to support and limit the auxiliary piston rod in radial direction.

[0013] Furthermore, it also includes a left end cover and a right end cover, which are respectively installed at the two axial ends of the damper cylinder to seal the damper cylinder.

[0014] Furthermore, the piston rod assembly also includes a piston base plate, which is installed on the axial end of the secondary piston rod and is located in the secondary cylinder body. The stiffness springs are provided in two, and the two stiffness springs are respectively a left stiffness spring provided between the left end cover and the piston base plate and a right stiffness spring provided between the limiting ring and the piston base plate.

[0015] Furthermore, the piston component also includes a left piston cover and a right piston cover, and the left piston cover and the right piston cover are respectively installed at the two axial ends of the piston cylinder to close the piston cylinder. There are two floating springs, and the two floating springs are a left floating spring installed between the left piston cover and the permanent magnet, and a right floating spring installed between the permanent magnet and the right piston cover.

[0016] Furthermore, the piston cylinder includes a left magnetic conductive ring, a left magnetic isolation ring, a middle magnetic conductive ring, a right magnetic isolation ring and a right magnetic conductive ring which are sequentially connected along the axial direction.

[0017] Furthermore, the main cylinder body is filled with damping fluid, and the damping fluid is made by mixing magnetorheological fluid and porous fiber material.

[0018] Beneficial effects of the present invention:

[0019] The present invention discloses a magnetorheological damper with frequency-dependent damping and nonlinear stiffness characteristics. Compared to existing electronically controlled magnetorheological dampers, the present invention's damper is passive and self-adjusts damping and stiffness without the need for external power. This significantly improves its adaptability and reliability in complex vibration environments, especially when the electronic control system fails, maintaining effective damping performance. By providing a piston member with a floating spring and a nonlinear stiffness spring within the secondary cylinder body, the damper can respond to vibration excitations of varying frequencies and amplitudes, providing high damping and stiffness at low frequencies and large amplitudes, and low damping and low stiffness at high frequencies and small amplitudes. This achieves good damping-stiffness matching across a wide frequency range, significantly enhancing the overall damping performance of the system. Using magnetorheological composite materials instead of traditional magnetorheological fluids not only improves the material's mechanical properties but also reduces the sealing requirements for the device, simplifying the design and manufacture of the damper while improving its durability and ease of maintenance. The inclined left variable gap cylinder and right variable gap cylinder structures have an effective damping gap thickness that decreases as the shock absorber stroke increases, and can automatically increase the damping force to adapt to the vibration control needs under different working conditions. The need for complex electronic control systems is reduced, and the shock absorber of the present invention has obvious advantages in manufacturing costs, operating costs, and maintenance costs. At the same time, it avoids potential failures of the electronic control system and improves the economy and safety of the equipment. The magnetorheological shock absorber of the present invention with frequency-variable damping and nonlinear stiffness characteristics can not only effectively solve the problem of insufficient adaptability and reliability of the existing technology in wide-band complex vibration situations, but also achieves significant optimization in material selection, structural design, cost control, etc., and has broad application prospects and important practical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of the present invention;

[0021] Figure 2 Schematic diagram of frequency-variable damping principle of an embodiment of the present invention (oscillator at equilibrium position);

[0022] Figure 3 A supplementary diagram of the frequency-variable damping principle of an embodiment of the present invention (the oscillator is at the right extreme position);

[0023] Figure markings: 1-left end cover, 2-left stiffness spring, 3-auxiliary cylinder body, 4-right stiffness spring, 5-limiting ring, 6-left variable gap cylinder, 7-main cylinder body, 8-piston cylinder, 801-left magnetic guide ring, 802-middle magnetic guide ring, 803-right magnetic guide ring, 804-right magnetic isolation ring, 805-left magnetic isolation ring, 9-right variable gap cylinder, 10-right end cover, 11-main piston rod, 12-right lifting ear, 13-right piston cover, 14-right floating spring, 15-right back iron, 16-left back iron, 17-permanent magnet, 18-left floating spring, 19-left piston cover, 20-circlip, 21-auxiliary piston rod, 22-piston base plate, 23-left lifting ear. DETAILED DESCRIPTION

[0024] It should be noted that, in the description of this specification, the terms "upper", "lower", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential" and the like indicate positions or location relationships based on the positions or location relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention. Unless otherwise specified, the left and right in this embodiment correspond to the attached drawings. Figure 1 In the left and right, axial and radial refer to the axial and radial directions of the main cylinder body. Unless otherwise specified, the installation in this embodiment can be achieved through various means such as threaded connection, welding or clamping.

[0025] The present invention discloses a magnetorheological vibration absorber with frequency-dependent damping and nonlinear stiffness characteristics, comprising:

[0026] The master cylinder assembly includes a master cylinder body 7 and a piston component, the piston component includes a piston cylinder 8, a permanent magnet 17 and a floating spring, the piston cylinder 8 is coaxial and can be driven to slide in the master cylinder body 7, the permanent magnet 17 can be driven to slide in the piston cylinder 8, the floating spring is installed in the piston cylinder 8, and the elastic force of the floating spring acts on the permanent magnet 17 in the axial direction; in this embodiment, the piston component also includes a left piston cover 19 and a right piston cover 13, the left piston cover 19 and the right piston cover 13 are respectively installed at the two axial ends of the piston cylinder 8 to close the piston cylinder 8, and there are two floating springs, the two floating springs are a left floating spring 18 installed between the left piston cover 19 and the permanent magnet 17, and a right floating spring 14 installed between the permanent magnet 17 and the right piston cover 13. When installed, the left floating spring 18 and the right floating spring 14 are both in a pre-stressed state. The left back iron 16 and the right back iron 15 are respectively mounted on the axial ends of the permanent magnet 17 via screws. In this embodiment, the stiffness of the floating spring and the mass of the permanent magnet 17 (including the left back iron 16 and the right back iron 15) are selected to ensure that the permanent magnet 17 (including the left back iron 16 and the right back iron 15) resonate together near the low-frequency resonance band of the main system. The back iron design at both ends of the permanent magnet 17 in this embodiment optimizes the magnetic circuit and improves the utilization rate of the magnetic field, so that a larger magnetic field excitation can be provided in the resonant state, thereby further enhancing the damping effect.

[0027] The auxiliary cylinder assembly includes an auxiliary cylinder body 3 and a plurality of stiffness springs. The auxiliary cylinder body 3 is interconnected with the main cylinder body 7 and is coaxially arranged. The plurality of stiffness springs are sequentially arranged in the auxiliary cylinder body 3 along the axial direction. Any stiffness spring is driven to be compressed or stretched synchronously with the sliding of the piston cylinder 8. In this embodiment, the stiffness spring is a conical helical structure, and any adjacent stiffness springs are arranged opposite each other. Since the conical helical spring is a nonlinear stiffness spring, its stiffness increases with the increase of deformation displacement. Therefore, it can provide the small stiffness required for high-frequency and small-amplitude working conditions and the large stiffness required for low-frequency and large-amplitude working conditions.

[0028] In this embodiment, the permanent magnet 17 resonates along with the resonance of the external excitation, thereby providing a larger magnetic field at the effective damping gap and increasing the damping force. In addition, as the shock absorber stroke increases, the thickness of the effective damping gap decreases, thereby also increasing the damping force. At the same time, the nonlinear stiffness characteristics of the conical coil spring inside the shock absorber are utilized to provide low stiffness when the stroke is small and increase its stiffness when the stroke increases. In other words, the shock absorber of this embodiment can avoid the use of an electronic control system and provide reliable and stable vibration reduction performance in wide-band complex vibration situations. The shock absorber can self-adjust the damping and stiffness according to the excitation frequency, that is, it provides high damping and high stiffness at low frequencies and large amplitudes, and provides low damping and low stiffness at high frequencies and small amplitudes.

[0029] In this embodiment, a variable gap assembly is also included, which includes a left variable gap cylinder 6 and a right variable gap cylinder 9. The inner wall surfaces of the left variable gap cylinder 6 and the right variable gap cylinder 9 are tapered structures with gradually increasing diameters along the radial direction. The left variable gap cylinder 6 and the right variable gap cylinder 9 are respectively installed on the left and right ends of the main cylinder body 7 with the ends with larger diameters facing the main cylinder body 7. The auxiliary cylinder body 3 is connected to the main cylinder body 7 through the left variable gap cylinder 6. The auxiliary cylinder body 3, the left variable gap cylinder 6, the main cylinder body 7 and the right variable gap cylinder 9 are connected in sequence through threaded connections to form a damper cylinder. As shown in the figure, the left variable gap cylinder 6 and the right variable gap cylinder 9 have inclined inner wall surfaces. As the shock absorber stroke increases, the effective damping gap thickness decreases, which can automatically increase the damping force to meet the vibration control requirements under different working conditions.

[0030] In this embodiment, a piston rod assembly is also included, which includes a main piston rod 11 and a secondary piston rod 21. The main piston rod 11 has a first end and a second end in the axial direction. The first end of the main piston rod 11 is located outside the damper cylinder, and the second end of the main piston rod 11 extends axially into the main cylinder body 7. The main piston rod 11 is inserted into the piston member, and the secondary piston rod 21 is installed on the second end of the main piston rod 11. The end of the secondary piston rod 21 extends axially into the secondary cylinder body 3.

[0031] In this embodiment, the secondary cylinder assembly further includes a retaining ring 5, which is mounted on the secondary cylinder body 3 and sleeved over the secondary piston rod 21 to support and radially retain the secondary piston rod 21. In this embodiment, the right side of the retaining ring 5 is positioned by a boss on the secondary cylinder body 3, and the left side is retained by a retaining ring 20.

[0032] In this embodiment, a left end cap 1 and a right end cap 10 are further included. The left end cap 1 and the right end cap 10 are respectively mounted on the axial ends of the damper cylinder to seal the damper cylinder. In this embodiment, the left end cap 1 is mounted on the left end of the auxiliary cylinder body 3 by means of a threaded connection, and the right end cap 10 is mounted on the right end of the right reducing cylinder by means of a threaded connection.

[0033] In this embodiment, the piston rod assembly also includes a piston base plate 22, which is installed on the axial end of the secondary piston rod 21 and is located in the secondary cylinder body 3. The stiffness springs are provided in two, and the two stiffness springs are respectively a left stiffness spring 2 provided between the left end cover 1 and the piston base plate 22 and a right stiffness spring 4 provided between the limiting ring 5 and the piston base plate 22. The left stiffness spring 2 and the right stiffness spring 4 are in a pre-stressed state in the initial state.

[0034] In this embodiment, the piston component also includes a left piston cover 19 and a right piston cover 13, and the left piston cover 19 and the right piston cover 13 are respectively installed at the two axial ends of the piston cylinder 8 to close the piston cylinder 8. There are two floating springs, and the two floating springs are a left floating spring 18 installed between the left piston cover 19 and the permanent magnet 17, and a right floating spring 14 installed between the permanent magnet 17 and the right piston cover 13. When installed, the left floating spring 18 and the right floating spring 14 are in a compressed state.

[0035] In this embodiment, the piston cylinder 8 comprises a left magnetic guide ring, a left magnetic isolation ring, a middle magnetic guide ring, a right magnetic isolation ring, and a right magnetic guide ring, all welded together in sequence along the axial direction. This arrangement ensures that when the main system is not in the low-frequency resonance range, the magnetic circuit reluctance is high. When the main system is in the low-frequency resonance range, the vibration amplitude of the floating assembly increases, and the magnetic circuit reluctance decreases, thereby providing a large magnetic field excitation at the effective damping gap. Seal grooves are also provided at both ends of the piston cylinder 8 to prevent the damping fluid from leaking into the piston cylinder 8.

[0036] In this embodiment, the main cylinder body 7 is filled with a damping fluid made from a mixture of magnetorheological fluid and porous fiber material. Magnetorheological composite materials, which are organically combined with magnetorheological fluid and porous fiber material, offer significantly improved mechanical properties compared to traditional magnetorheological fluids. Furthermore, since the entire chamber does not need to be filled with magnetorheological fluid, the sealing requirements for the device are lower.

[0037] In this embodiment, the retaining ring 5, the piston base plate 22, and the inner surface of the left end cap 1 are all machined with annular grooves for securing the spring. As shown in the figure, this embodiment is also provided with a left lifting lug 23 and a right lifting lug 12. The left lifting lug 23 is threadedly connected to the left end cap 1, and the right lifting lug 12 is threadedly connected to the outer end of the main piston rod 11. In this embodiment, the piston cylinder 8 is clamped at both ends by two piston caps and positioned by the shoulder between the secondary piston rod 21 and the piston caps. In this embodiment, as shown in the figure, one end of the secondary piston rod 21 is threadedly connected to the piston base plate 22, and the other end is threadedly connected to the end of the main piston rod 11.

[0038] In actual use, when the system vibration frequency is not in the resonance range, such as Figure 2 As shown, the vibration amplitude of the permanent magnet 17 is small. Since the piston cylinder 8 is made of alternating magnetic conductive and magnetic insulating materials, the magnetic resistance in this state is large, and the magnetic field will leak more in the air gap. Therefore, the magnetic field passing through the effective damping gap is small, thereby providing a small damping force. When the vibration frequency of the system is in the resonant frequency band, as shown in FIG. Figure 3 As shown, the permanent magnet 17 vibrator resonates with the system, and its motion amplitude is large. In this state, the magnetic resistance of the magnetic circuit is small, and the back iron at both ends of the permanent magnet 17 is connected to the magnetic material, so the magnetic field at the effective damping gap is increased, and the damping force is increased.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A magnetorheological damper with frequency-dependent damping and nonlinear stiffness characteristics, characterized in that: include: A master cylinder assembly, comprising a master cylinder body and a piston member, wherein the piston member comprises a piston barrel, a permanent magnet, and a floating spring, wherein the piston barrel is coaxially and drivably slidably disposed in the master cylinder body, the permanent magnet is drivably slidably disposed in the piston barrel, and the floating spring is installed in the piston barrel, wherein the elastic force of the floating spring acts axially on the permanent magnet; A secondary cylinder assembly, the secondary cylinder assembly comprising a secondary cylinder body and a plurality of stiffness springs, the secondary cylinder body being interconnected and coaxially arranged with the primary cylinder body, the plurality of stiffness springs being sequentially arranged axially within the secondary cylinder body, any of the stiffness springs being driven to be compressed or stretched synchronously with the sliding of the piston cylinder; The stiffness spring is a conical spiral structure, and any adjacent stiffness springs are arranged opposite to each other; The piston cylinder comprises a left magnetic conductive ring, a left magnetic isolation ring, a middle magnetic conductive ring, a right magnetic isolation ring and a right magnetic conductive ring which are sequentially connected along the axial direction.

2. The magnetorheological damper with frequency-dependent damping and nonlinear stiffness characteristics according to claim 1, characterized in that: It also includes a variable gap component, which includes a left variable gap cylinder and a right variable gap cylinder. The inner wall surfaces of the left variable gap cylinder and the right variable gap cylinder are conical structures whose radial diameters gradually increase. The left variable gap cylinder and the right variable gap cylinder are respectively installed on the left and right ends of the main cylinder body with the end with a larger diameter facing the main cylinder body. The auxiliary cylinder body is connected to the main cylinder body through the left variable gap cylinder. The auxiliary cylinder body, the left variable gap cylinder, the main cylinder body and the right variable gap cylinder constitute the damper cylinder.

3. The magnetorheological damper with frequency-dependent damping and nonlinear stiffness characteristics according to claim 2, characterized in that: It also includes a piston rod assembly, which includes a main piston rod and a secondary piston rod. The main piston rod has a first end and a second end in the axial direction. The first end of the main piston rod is located outside the damper cylinder, and the second end of the main piston rod extends axially into the main cylinder body. The main piston rod is inserted into the piston member, and the secondary piston rod is installed on the second end of the main piston rod, and the end of the secondary piston rod extends axially into the secondary cylinder body.

4. The magnetorheological damper with frequency-dependent damping and nonlinear stiffness characteristics according to claim 3, characterized in that: The auxiliary cylinder assembly further comprises a limiting ring, which is mounted on the auxiliary cylinder body and sleeved on the auxiliary piston rod to support and limit the auxiliary piston rod in radial direction.

5. The magnetorheological damper with frequency-dependent damping and nonlinear stiffness characteristics according to claim 3, characterized in that: It also includes a left end cover and a right end cover, which are respectively installed at the two axial ends of the damper cylinder to seal the damper cylinder.

6. The magnetorheological damper with frequency-dependent damping and nonlinear stiffness characteristics according to claim 4 or 5, characterized in that: The piston rod assembly also includes a piston base plate, which is installed on the axial end of the secondary piston rod and is located in the secondary cylinder body. The two stiffness springs are provided with two stiffness springs, which are a left stiffness spring provided between the left end cover and the piston base plate and a right stiffness spring provided between the limit ring and the piston base plate.

7. The magnetorheological damper with frequency-dependent damping and nonlinear stiffness characteristics according to claim 1, characterized in that: The piston component also includes a left piston cover and a right piston cover, which are respectively installed at the two axial ends of the piston cylinder to close the piston cylinder. There are two floating springs, and the two floating springs are a left floating spring installed between the left piston cover and the permanent magnet, and a right floating spring installed between the permanent magnet and the right piston cover.

8. The magnetorheological damper with frequency-dependent damping and nonlinear stiffness characteristics according to claim 1, characterized in that: The main cylinder body is filled with damping fluid, which is made by mixing magnetorheological fluid and porous fiber material.

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