Magneto-rheological shock absorber with frequency-variable damping and nonlinear stiffness characteristics

Abstract

A main cylinder barrel assembly comprises a main cylinder barrel body and a piston component, the piston component comprises a piston barrel, a permanent magnet and a floating spring, the piston barrel is coaxially and slidably arranged on the main cylinder barrel body in a driven mode, the permanent magnet is arranged on the piston barrel, and the floating spring is arranged on the piston barrel. The permanent magnet is slidably arranged in the piston cylinder in a driven mode, the floating spring is installed in the piston cylinder, and the elastic force of the floating spring acts on the permanent magnet in the axial direction. The auxiliary cylinder barrel assembly comprises an auxiliary cylinder barrel body and a plurality of stiffness springs, the auxiliary cylinder barrel body and the main cylinder barrel body are coaxially arranged, and the stiffness springs are arranged in the auxiliary cylinder barrel body in a follow-up mode. The shock absorber can respond to vibration excitation of different frequencies and amplitudes, large damping and large rigidity are provided when the low frequency is large in amplitude, small damping and small rigidity are provided when the high frequency is small in amplitude, and therefore the good damping rigidity matching characteristic can be obtained in the wide frequency band, and the overall shock absorption performance of a system is remarkably improved.

Description

Technical Field

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

[0002] As an intelligent vibration reduction device that uses magnetorheological effect to change the properties of fluid and thus change the damping characteristics of the shock absorber, magnetorheological shock absorbers have been widely used in wide-band vibration reduction applications such as vehicle suspension systems, precision mechanical platforms, aerospace, and bridges in recent years. Traditional magnetorheological shock absorbers generate a magnetic field through external input current to control the rheological properties of the magnetorheological fluid, thereby adjusting the damping force of the shock absorber.

[0003] For some complex mechanical systems, they will be subjected to vibration excitations with large differences in a wide frequency range at different working stages (for example, the engine is subjected to low-frequency and large-amplitude vibrations at the startup stage, and high-frequency and small-amplitude vibrations at the stable operation stage). If the vibrations are not effectively reduced, the system's working efficiency will decrease or even fail. The current magnetorheological shock absorber mainly achieves effective vibration reduction through external controllable current input, and its stiffness generally changes linearly. If the electronic control system fails during operation, the shock absorber will fail instantly, which is extremely unfavorable for mechanical equipment that works in complex and harsh environments for a long time.

[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 a 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 stiffness matching characteristics can be obtained in a wide frequency band, and the overall shock absorption performance of the system can be significantly improved.

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

[0007] A master cylinder assembly, the master cylinder assembly comprising a master cylinder body and a piston member, the piston member comprising a piston cylinder, a permanent magnet and a floating spring, the piston cylinder being coaxially and drivably slidably arranged in the master cylinder body, the permanent magnet being drivably slidably arranged in the piston cylinder, the floating spring being installed in the piston cylinder, the elastic force of the floating spring acting on the permanent magnet in the axial direction;

[0008] A secondary cylinder assembly, the secondary cylinder assembly includes a secondary cylinder body and multiple stiffness springs, the secondary cylinder body is interconnected with the main cylinder body and coaxially arranged, multiple stiffness springs are arranged in the secondary cylinder body in sequence along the axial direction, and 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 at 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, and the auxiliary cylinder body, the left variable gap cylinder, the main cylinder body and the right variable gap cylinder constitute a damper cylinder.

[0010] Furthermore, the stiffness spring is a conical spiral 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 also includes a limiting ring, which is installed on the auxiliary cylinder body and is sleeved on the auxiliary piston rod support and radially limits the auxiliary piston rod.

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

[0014] Furthermore, the piston rod assembly also includes a piston base plate, which is installed on the axial end of the auxiliary piston rod and is located in the auxiliary 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 limit 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. Two floating springs are provided, and the two floating springs are respectively 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 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.

[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 with the existing electrically controlled magnetorheological damper, the damper of the present invention is designed to be passive, and can realize self-adjustment of damping and stiffness without external power supply, which greatly improves its adaptability and reliability in complex vibration environments, especially when the electronic control system fails, it can still maintain effective damping performance. Through the piston component provided with a floating spring and the nonlinear stiffness spring provided in the auxiliary cylinder body, the damper 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 in a wide frequency band, and the overall damping performance of the system can be significantly improved. The use of magnetorheological composite materials instead of traditional magnetorheological fluids not only improves the mechanical properties of the materials, but also reduces the requirements for the sealing of the device, making the design and manufacture of the damper simpler, while improving its durability and maintenance convenience. The inclined left variable gap cylinder and right variable gap cylinder structures can automatically increase the damping force as the shock absorber stroke increases, while reducing the thickness of the effective damping gap, to meet the vibration control requirements under different working conditions. The demand for complex electronic control systems is reduced, and the shock absorber of the present invention has obvious advantages in manufacturing cost, operating cost and maintenance cost, while avoiding potential failures of the electronic control system and improving the economy and safety of the equipment. The magnetorheological shock absorber with frequency-variable damping and nonlinear stiffness characteristics of the present invention can not only effectively solve the problem of insufficient adaptability and reliability of the prior art in wide-band complex vibration situations, but also achieves significant optimization in material selection, structural design, cost control and other aspects, 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 The frequency-variable damping principle diagram of an embodiment of the present invention (the oscillator is in a balanced 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 positional relationships based on the positions or positional relationships shown in the 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 cannot 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 connected by various means such as threaded connection, welding or clamping.

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

[0026] A master cylinder assembly, the master cylinder assembly includes a master cylinder body 7 and a piston member, the piston member includes a piston barrel 8, a permanent magnet 17 and a floating spring, the piston barrel 8 is coaxially and drivably slidably arranged in the master cylinder body 7, the permanent magnet 17 is drivably slidably arranged in the piston barrel 8, the floating spring is installed in the piston barrel 8, and the elastic force of the floating spring acts on the permanent magnet 17 along the axial direction; in this embodiment, the piston member 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 axial ends of the piston barrel 8 to close the piston barrel 8, and there are two floating springs, the two floating springs are respectively 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 installed by screws at the two axial ends of the permanent magnet 17. 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) resonates together near the low-frequency resonance frequency band of the main system. The back iron design at both ends of the permanent magnet 17 in this embodiment optimizes the magnetic circuit, improves the utilization rate of the magnetic field, and can provide a larger magnetic field excitation in the resonant state, thereby further enhancing the damping effect.

[0027] Auxiliary cylinder assembly, the auxiliary cylinder assembly includes an auxiliary cylinder body 3 and a plurality of stiffness springs, the auxiliary cylinder body 3 and the main cylinder body 7 are interconnected and coaxially arranged, and the plurality of stiffness springs are sequentially arranged in the auxiliary cylinder body 3 along the axial direction, and 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 spiral structure, and any adjacent stiffness springs are arranged oppositely. Since the conical spiral spring is a nonlinear stiffness spring, its stiffness increases with the increase of deformation displacement, so 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 will resonate with the resonance of the external excitation, thereby providing a larger magnetic field at the effective damping gap and improving the damping force; in addition, as the stroke of the shock absorber increases, the thickness of its effective damping gap becomes smaller, so the damping force can also be improved. At the same time, the nonlinear stiffness characteristics of the conical coil spring inside the shock absorber are utilized to provide a small stiffness when its stroke is small, and to improve 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 large damping and large stiffness at low frequencies and large amplitudes, and provides small damping and small stiffness at high frequencies and small amplitudes.

[0029] In this embodiment, a variable gap assembly is also included, and the variable gap assembly includes a left variable gap cylinder 6 and a right variable gap cylinder 9. The inner wall surface of the left variable gap cylinder 6 and the right variable gap cylinder 9 is a tapered structure with a gradually increasing diameter along the radial direction. The left variable gap cylinder 6 and the right variable gap cylinder 9 are respectively installed at the left and right ends of the main cylinder body 7 with the end with a larger diameter 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 by threaded connection to form a damper cylinder. As shown in the figure, the left variable gap cylinder 6 and the right variable gap cylinder 9 structure with an inclined inner wall surface, as the shock absorber stroke increases, the effective damping gap thickness decreases, and the damping force can be automatically increased to meet the vibration control requirements under different working conditions.

[0030] In this embodiment, a piston rod assembly is also included, and the piston rod assembly includes a main piston rod 11 and a sub-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 penetrated by the piston member, and the sub-piston rod 21 is installed on the second end of the main piston rod 11, and the end of the sub-piston rod 21 extends axially into the sub-cylinder body 3.

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

[0032] In this embodiment, a left end cap 1 and a right end cap 10 are also included. The left end cap 1 and the right end cap 10 are respectively installed at the two ends of the axial direction of the damper cylinder to close the damper cylinder. In this embodiment, the left end cap 1 is installed on the left end of the auxiliary cylinder body 3 by threaded connection, and the right end cap 10 is installed on the right end of the right variable diameter cylinder by 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 limit 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. The two floating springs are provided, 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 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 welded and connected in sequence along the axial direction. Such a setting can ensure that when the main system is not in the low-frequency resonance section, the magnetic circuit magnetic resistance is large; when the main system is in the low-frequency resonance section, the vibration amplitude of the floating component increases, and the magnetic circuit magnetic resistance is small, thereby providing a large magnetic field excitation at the effective damping gap. In addition, sealing grooves are provided at both ends of the piston cylinder 8 to prevent the damping liquid from leaking into the piston cylinder 8.

[0036] In this embodiment, the main cylinder body 7 is filled with damping fluid, and the damping fluid is made of a mixture of magnetorheological fluid and porous fiber material. The magnetorheological composite material is an organic configuration of magnetorheological fluid and porous fiber material, and its mechanical properties are greatly improved compared to traditional magnetorheological fluid, and there is no need to fill the entire chamber with magnetorheological fluid, and the sealing requirements of the device are relatively low.

[0037] In this embodiment, the stop ring 5, the piston bottom plate 22, and the inner side of the left end cover 1 are all processed with annular grooves for fixing the spring; as shown in the figure, this embodiment is also provided with a left lifting ear 23 and a right lifting ear 12, the left lifting ear 23 is threadedly connected to the left end cover 1, and the right lifting ear 12 is threadedly connected to the outer end of the main piston rod 11. The two end surfaces of the piston cylinder 8 in this embodiment are clamped by two piston covers and positioned by the shoulder between the auxiliary piston rod 21 and the piston cover. In this embodiment, one end of the auxiliary piston rod 21 as shown in the figure is threadedly connected to the piston bottom 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 section, such as Figure 2 As shown, the vibration amplitude of the permanent magnet 17 is small. Since the piston cylinder 8 is made of magnetic conductive and magnetic insulating materials spliced ​​alternately, the magnetic resistance in this state is large, and the magnetic field will have more leakage in the air gap, so 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, such as Figure 3 As shown, the vibrator of the permanent magnet 17 resonates with the system, and its movement amplitude is large. In this state, the magnetic resistance of the magnetic circuit is small, and the back irons at both ends of the permanent magnet 17 are connected to the magnetic conductive 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 solution of the present invention rather than to limit it. 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 solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should 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, the master cylinder assembly comprising a master cylinder body and a piston member, the piston member comprising a piston cylinder, a permanent magnet and a floating spring, the piston cylinder being coaxially and drivably slidably arranged in the master cylinder body, the permanent magnet being drivably slidably arranged in the piston cylinder, the floating spring being installed in the piston cylinder, the elastic force of the floating spring acting on the permanent magnet in the axial direction; A secondary cylinder assembly, the secondary cylinder assembly includes a secondary cylinder body and multiple stiffness springs, the secondary cylinder body is interconnected with the main cylinder body and coaxially arranged, multiple stiffness springs are arranged in the secondary cylinder body in sequence along the axial direction, and any of the stiffness springs is driven to be compressed or stretched synchronously with the sliding of the piston cylinder.

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 diameters gradually increase along the radial direction. The left variable gap cylinder and the right variable gap cylinder are respectively installed at 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 a damper cylinder.

3. The magnetorheological damper with frequency-dependent damping and nonlinear stiffness characteristics according to claim 1, characterized in that: The stiffness spring is a conical spiral structure, and any adjacent stiffness springs are arranged opposite to each other.

4. 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.

5. The magnetorheological damper with frequency-dependent damping and nonlinear stiffness characteristics according to claim 4, characterized in that: The auxiliary cylinder assembly also includes a limiting ring, which is installed on the auxiliary cylinder body and sleeved on the auxiliary piston rod support and radially limits the auxiliary piston rod.

6. The magnetorheological damper with frequency-dependent damping and nonlinear stiffness characteristics according to claim 2, characterized in that: It also includes a left end cover and a right end cover, which are respectively and correspondingly mounted on the two axial ends of the damper cylinder to seal the damper cylinder.

7. The magnetorheological damper with frequency-dependent damping and nonlinear stiffness characteristics according to claim 4, characterized in that: The piston rod assembly also includes a piston base plate, which is installed on the axial end of the auxiliary piston rod and is located in the auxiliary 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 limit ring and the piston base plate.

8. 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, 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. Two floating springs are provided, and the two floating springs are respectively 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.

9. The magnetorheological damper with frequency-dependent damping and nonlinear stiffness characteristics according to claim 1, characterized in that: 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.

10. 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, and the damping fluid is made by mixing magnetorheological fluid and porous fiber material.

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