Dual-mode magnetorheological damper for vibration reduction

Abstract

The invention relates to a dual-mode magnetorheological damper for vibration reduction. The dual-mode magnetorheological damper comprises a large-displacement shear damping part and a small-displacement extrusion damping part. The large-displacement shear damping part comprises a first piston rod, an inner cylinder and an outer cylinder which are sleeved from inside to outside, the first piston rod is sleeved with a piston, the ends, right facing the small-displacement extrusion damping part, of the inner cylinder and the outer cylinder are provided with cover plates, the other ends of the inner cylinder and the outer cylinder are provided with upper end covers, and the end of the first piston rod penetrates out of the upper end covers. The piston is located in a space defined by the inner cylinder, the upper end cover and the cover plate and forms a gap with the inner wall of the inner cylinder. The small-displacement extrusion damping part comprises a second piston rod and an inner sleeve which are sequentially sleeved from inside to outside, the inner sleeve is sleeved with a first magnet exciting coil, a plurality of piston discs are arranged in the length direction of the second piston rod, an upper base is arranged at one end of the inner sleeve, a lower base is arranged at the other end of the inner sleeve, and a plurality of annular partition discs are arranged on the inner wall in the length direction of the inner sleeve; the piston discs and the annular partition discs are arranged in a staggered mode. According to the invention, low-frequency large-amplitude vibration and high-frequency small-amplitude vibration can be effectively damped.

Description

Technical Field

[0001] The invention belongs to the field of damping devices, and in particular relates to a dual-mode magnetorheological damper for vibration reduction. Background Art

[0002] Due to the characteristics of external excitation and the characteristics of the excitation source itself, some systems have the following vibration characteristics: most of the time, they are manifested as small-amplitude high-frequency vibrations, and when they are started or suddenly disturbed by external disturbances, they will produce large-amplitude low-frequency impact vibrations. For example, in a water supply pipeline, when the water supply pump is started, since the initial state of the entire pipeline pressure is zero, the system starts with an impact jump phenomenon, and low-frequency and large-amplitude fluctuations will occur. After starting smoothly, it enters a high-frequency and small-amplitude state. In addition, when the load demand fluctuates, the system pressure may also fluctuate at a low frequency and a large amplitude. Similar systems are relatively common, so when conducting vibration reduction research on such systems, it is necessary to consider both the low-frequency and small-amplitude vibration reduction under normal circumstances, and the occasional low-frequency and large-amplitude impact vibration of the system.

[0003] A magnetorheological damper is an intelligent material that uses magnetorheological fluid. By changing the current applied to the coil to change the magnetic field strength, the flow characteristics and damping force of the magnetorheological fluid are controlled. The magnetorheological damper can be used very effectively for vibration reduction.

[0004] Some current magnetorheological dampers only work in a single mode, such as shear mode or extrusion mode, and can only reduce vibrations of high frequency and small amplitude or large amplitude impact vibrations, but cannot effectively reduce vibrations of both types. Summary of the invention

[0005] We hope to provide a magnetorheological damper that can simultaneously reduce the vibration of both low-frequency large-amplitude impact vibration and high-frequency small-amplitude vibration.

[0006] The present application provides a dual-mode magnetorheological damper for vibration reduction, which adopts the following technical solution: A dual-mode magnetorheological damper for vibration reduction, comprising: a large displacement shear damping portion and a small displacement extrusion damping portion arranged along the length direction; The large displacement shear damping part comprises a first piston rod, an inner cylinder and an outer cylinder which are sleeved in sequence from the inside to the outside, a piston is sleeved on the inner end of the first piston rod, a cover plate is provided at the ends of the inner cylinder and the outer cylinder facing the small displacement extrusion damping part, and an upper end cover is provided at the other ends, the outer end of the first piston rod passes through the upper end cover, the piston is located in the space surrounded by the inner cylinder, the upper end cover and the cover plate, and forms a gap with the inner wall of the inner cylinder; The small displacement extrusion damping part includes a second piston rod and an inner sleeve which are sequentially sleeved from the inside to the outside, the inner sleeve is sleeved with a first excitation coil, a plurality of piston discs are arranged along the length of the second piston rod, an upper seat body is arranged at the end of the inner sleeve facing the large displacement shear damping part, and a lower seat body is arranged at the other end, a plurality of annular spacer discs are arranged on the inner wall along the length of the inner sleeve, and the piston discs and the annular spacer discs are arranged alternately.

[0007] By adopting the above technical solution, when the external vibration drives the first piston rod to extend and retract, the piston moves in the inner cylinder, and the magnetorheological fluid forms a shear flow between the piston and the inner wall of the inner cylinder. Since the flow area of ​​the gap is very small, a damping effect is formed on the magnetorheological fluid, thereby generating a damping force on the vibration, which can reduce low-frequency and large-amplitude impact vibrations; When the first excitation coil is energized, a magnetic field is formed, which will cause an axial magnetic flux to form between the right end face of the upper seat body and the left end face of the piston disc in the sealed oil chamber, and between the piston disc and the annular spacer, and between the piston disc and the lower seat body. These magnetic fluxes will generate damping force on the movement of the piston disc, which can reduce high-frequency and small-amplitude vibrations, and thus can effectively reduce vibrations in both vibration systems.

[0008] Optionally, a circular groove is opened in the middle of the piston along the circumferential direction, and a second excitation coil is installed in the circular groove.

[0009] By adopting the above technical solution, when current is passed through the second excitation coil, a magnetic field is formed in the annular gap of the piston, and the magnetorheological fluid flowing through the annular gap forms a solid-like magnetic flux chain due to the magnetorheological effect, which further increases the damping force.

[0010] Optionally, a permanent magnet is installed between the inner cylinder and the outer cylinder and at one end close to the cover plate.

[0011] By adopting the above technical solution, when the second excitation coil on the piston moves into the cavity surrounded by the permanent magnet, the permanent magnet will further enhance the strength of the magnetic flux in the annular gap between the piston and the inner cylinder, thereby further increasing the damping force.

[0012] Optionally, an outer sleeve is sleeved on the inner sleeve to form a cavity between the two, and the outer wall of the inner sleeve forms an annular groove with the right end surface of the upper seat body and the left end surface of the lower seat body respectively, and the first excitation coil is arranged in the annular groove.

[0013] By adopting the above technical solution, an annular slot is provided to facilitate the fixation of the first excitation coil, and a cavity is formed between the inner sleeve and the outer sleeve for placing the electrical connection wire, and the two wire ends of the first excitation coil pass through the outer sleeve.

[0014] Optionally, three piston discs are provided, and two annular spacer discs are provided, and the annular spacer disc is located between two adjacent piston discs.

[0015] By adopting the above technical solution, multiple piston discs are set and two adjacent ones are separated by an annular spacer. An axial magnetic chain can be formed between the movable piston disc and the fixed annular spacer. An axial magnetic chain is formed between each piston disc and the annular spacer, thereby forming multiple axial magnetic chains. The magnetic chain will generate a damping force on the movement of each piston disc, and the damping force is more uniform.

[0016] Optionally, an oil hole is opened on the cover plate to form a cavity between the cover plate and the upper seat body. When the piston moves toward the upper end cover, the magnetorheological fluid in the cavity between the upper seat body and the cover plate can flow into the rodless cavity of the piston through the oil hole.

[0017] By adopting the above technical solution, when the piston moves to the left, the magnetorheological fluid in the cavity between the upper seat body and the cover plate can flow into the rodless cavity on the right side of the piston through the oil hole, thereby playing a role of fluid replenishment.

[0018] Optionally, both sides of the piston are cylindrical outer surfaces, and four axial long strip bosses are provided on the cylindrical outer surface of one side, and the bosses are in contact with the inner surface of the inner cylinder.

[0019] By adopting the above technical solution, the top surface of the boss fits with the inner surface of the inner tube, playing an axial guiding role, ensuring that the entire piston will not radially deviate from the central axis when moving left and right in the inner tube.

[0020] Optionally, a plurality of axial positioning sleeves are provided on the second piston rod, and the piston disc is provided between two adjacent axial positioning sleeves.

[0021] By adopting the above technical solution, the axial positioning sleeve can play a role in positioning the piston disc.

[0022] Optionally, a dust cover is provided on a side of the outer cylinder away from the small-displacement extrusion damping portion.

[0023] By adopting the above technical solution, the dust cover can play a role in preventing dust from reaching the large displacement shear damping part.

[0024] In summary, the present application includes at least one of the following beneficial technical effects: This dual-mode magnetorheological shock absorber consists of two parts: a large-displacement shear damping part and a small-displacement extrusion damping part. The piston of the large-displacement shear damping part has a large working stroke and works in a shear working mode, which can achieve vibration reduction of large-displacement impacts. The small-displacement extrusion damping part has a large piston area, a small working stroke and works in an extrusion working mode, which can achieve effective vibration reduction of high-frequency vibrations. There is an oil hole between the two. When the first piston rod of the large-displacement shear damping part extends and needs oil replenishment, the small-displacement damping part can quickly replenish oil for it through the oil hole. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the overall structure of a dual-mode magnetorheological damper for vibration reduction of the present application; Figure 2 is a schematic diagram of the structure of the piston on the first piston rod embodying the present application; Figure 3 yes Figure 2 AA section view; Figure 4 yes Figure 2 BB cross-sectional view.

[0026] Description of reference numerals: 1. Single ear; 2. Bushing; 3. Upper end cover; 4. O-ring; 5. Fixing screw; 7. O-ring; 6. V-ring sealing ring; 8. V-ring sealing ring; 9. V-ring sealing ring; 10. Magnetorheological fluid; 11. Piston; 111. Boss; 12. Second excitation coil; 13. Spring washer; 14. Axial nut; 18. Cover plate; 181. Oil hole; 191. Cavity; 55. first piston rod; 56. inner cylinder; 57. outer cylinder; 58. dust cover; 59. dynamic seal; 54. magnetic coil sealing coating; 53. permanent magnet; 19, upper seat; 27, lower seat; 271, chamber; 272, oil outlet; 24, piston disc; 46, piston disc; 40, piston disc; 22, annular spacer; 42, annular spacer; 21, retaining ring for hole; 23, retaining ring for hole; 41, retaining ring for hole; 43, retaining ring for hole; 44, axial positioning sleeve; 45, axial positioning sleeve; 47, axial positioning sleeve; 31, second piston rod; 49, axial positioning nut; 48, spring washer; 3 4. Bottom cover plate; 16. Cover plate screws; 51. Cover plate screws; 15. Spring washers; 52. Spring washers; 29. ​​Bottom cover plate screws; 35. Bottom cover plate screws; 28. Spring washers; 36. Spring washers; 25. First excitation coil; 17. O-ring; 20. O-ring; 26. O-ring; 37. O-ring; 30. Dynamic seal; 38. Inner sleeve; 39. Outer sleeve; 32. Exhaust screw; 33. Sealing washer. DETAILED DESCRIPTION

[0027] The following is combined with Figure 1-Figure 4 This application is described in further detail.

[0028] The embodiment of the present application discloses a dual-mode magnetorheological damper for vibration reduction.

[0029] See also Figure 1 , a dual-mode magnetorheological damper for vibration reduction, comprising a large displacement shear damping part and a small displacement extrusion damping part arranged along the length direction, the large displacement shear damping part is located on the left side, and the small displacement extrusion damping part is located on the right side. In this embodiment, the upper, lower, left, and right are all attached Figure 1 The orientation in is taken as the reference.

[0030] The large displacement shear damping part is composed of an outer cylinder 57, an inner cylinder 56, a first piston rod 55, a piston 11, an upper end cover 3, a cover plate 18, a single ear 1, a bushing 2, a dust cover 58, a dynamic seal 59, an O-ring 4, an O-ring 7, a V-ring 6, a sealing ring 8, a sealing ring 9, a fixing screw 5, an axial nut 14, a spring washer 13, a magnetorheological fluid 10, a second excitation coil 12, an excitation coil sealing coating 54 and a permanent magnet 53.

[0031] The piston 11 is sleeved on the first piston rod 55 along the axial direction and fixed on the first piston rod 55 by the axial nut 14, and the spring washer 13 is located between the axial nut 14 and the piston 11. The first piston rod 55 and the piston 11 are located in the inner cylinder 56, and the outer cylinder 57 is sleeved on the inner cylinder 56. The left ends of the inner cylinder 56 and the outer cylinder 57 are fixed on the upper end cover 3, and the right ends are fixed on the cover plate 18. The inner cylinder 56, the upper end cover 3, the cover plate 18, the dynamic seal 59, the O-ring 4, the O-ring 7, the V-ring 6, the sealing ring 8 and the sealing ring 9 form a sealing oil chamber of the large displacement shear damping part.

[0032] The first piston rod 55 extends out of the oil chamber through the center hole of the upper end cover 3 and is connected to the single ear 1. The bushing 2 is interference fit on the single ear 1. The piston 11 divides the oil chamber into a rod chamber on the left and a rodless chamber on the right. There is a circular gap between the piston 11 and the inner wall of the inner tube 56.

[0033] When external vibration drives the first piston rod 55 to extend and retract through the single ear 1, the piston 11 moves in the inner cylinder 56, and the magnetorheological fluid 10 forms a shear flow between the piston 11 and the inner wall of the inner cylinder 56. Since the flow area of ​​the gap is very small, a damping effect is formed on the magnetorheological fluid 10, thereby generating a damping force on the vibration, which can reduce low-frequency and large-amplitude impact vibrations.

[0034] A circular groove is opened in the middle of the piston 11 along the circumferential direction, and a second excitation coil 12 is installed in the circular groove. When current is passed through the second excitation coil 12, a magnetic field is formed in the annular gap of the piston 11. The magnetorheological fluid 10 flowing through the annular gap will form a solid-like magnetic flux chain due to the magnetorheological effect, which will further increase the damping force. The magnitude of the damping force is directly related to the current passed through. Therefore, the magnitude of the damping force can be adjusted in real time by controlling the magnitude of the current passed through, so as to specifically reduce low-frequency and large-amplitude impact vibrations.

[0035] The excitation coil sealing coating 54 is arranged on the outside of the second excitation coil 12, and the material may be epoxy resin, thermoplastic plastic, rubber, etc.

[0036] A permanent magnet 53 is installed between the inner cylinder 56 and the outer cylinder 57 and at one end close to the cover plate 18. The permanent magnet 53 is used to generate a magnetic field with the same magnetic properties as the second excitation coil 12. When the second excitation coil 12 on the piston 11 moves into the cavity surrounded by the permanent magnet 53, the permanent magnet 53 will further enhance the strength of the magnetic flux in the annular gap between the piston 11 and the inner cylinder 56, thereby further increasing the damping force, thereby playing a role of end buffering and adapting to stronger low-frequency and large-amplitude impact vibrations.

[0037] In addition, the permanent magnet 53 may also be an excitation coil, which can also play a buffering role.

[0038] A dust cover 58 for preventing dust is provided on one side of the outer cylinder 57 away from the small displacement extrusion damping portion. The dust cover 58 moves with the first piston rod 55 and prevents it from being exposed to the air.

[0039] The small displacement extrusion damping part is composed of an upper seat body 19, a lower seat body 27, a piston disc 46, a piston disc 24 and a piston disc 40, an annular spacer 22 and an annular spacer 42, a hole retaining ring 21, a hole retaining ring 23, a hole retaining ring 41 and a hole retaining ring 43, an axial positioning sleeve 47, an axial positioning sleeve 45 and an axial positioning sleeve 44, a second piston rod 31, an axial positioning nut 49, a spring washer 48, a bottom cover plate 34, a cover plate screw 16 and a cover plate screw 51 and a spring washer 15 and a spring washer 52, a bottom cover plate screw 29 and a bottom cover plate screw 35 and a spring washer 28 and a spring washer 36, a first excitation coil 25, an O-ring 17, an O-ring 37, an O-ring 20 and an O-ring 26, a dynamic seal 30, an inner sleeve 38, an outer sleeve 39, an exhaust screw 32 and a sealing washer 33.

[0040] The upper seat body 19, the lower seat body 27 and the inner sleeve 38 form a sealed oil chamber, and the two ends are sealed by O-rings 17, 37, 20, 26 and dynamic seals 30 respectively. The oil chamber is also filled with magnetorheological fluid 10.

[0041] A chamber 271 is formed between the lower seat body 27 and the bottom cover plate 34, and an oil outlet hole 272 is formed on the lower seat body 27 to connect the chamber 271 and the sealed oil chamber, so that the magnetorheological fluid 10 in the cavity 271 can be added to the chamber where the piston disc is located. An exhaust hole is provided on the bottom cover plate 34, and the exhaust hole is blocked by an exhaust screw 32.

[0042] The inner sleeve 38 is sleeved on the second piston rod 31 and the piston disc, and an annular gap is left between the piston disc 46, the piston disc 24 and the piston disc 40 and the inner sleeve 38. The three piston discs 46, the piston disc 24 and the piston disc 40 are arranged at intervals along the length direction of the second piston rod 31, and the annular spacer discs 22 and the annular spacer discs 42 are vertically fixed on the inner side wall of the inner sleeve 38, and an annular spacer disc is arranged between two adjacent piston discs.

[0043] One end of the piston rod 31 passes through the upper seat body 19, and the other end passes through the center hole of the lower seat body 27 and the bottom cover plate 34 and is installed on the center line and can slide axially along the center line. The piston plate 46, the piston plate 24 and the piston plate 40 are fixed on the piston rod 31 through the shoulder of the piston rod 31 and the axial positioning sleeve 47, the axial positioning sleeve 45 and the axial positioning sleeve 44 and the axial positioning nut 49, and the spring washer 48 is arranged between the axial positioning nut 49 and the end of the piston rod 31. A piston plate is arranged between two adjacent axial positioning sleeves and can slide axially in the oil chamber.

[0044] The inner sleeve 38 is sleeved with the outer sleeve 39 and a cavity is formed between the two. The outer wall of the inner sleeve 38 forms an annular groove with the right end face of the upper seat body 19 and the left end face of the lower seat body 27. The first excitation coil 25 is arranged in the annular groove. When the first excitation coil 25 is energized, a magnetic field is formed, which will form an axial magnetic flux between the right end face of the upper seat body 19 and the left end face of the piston disc 46 in the sealed oil chamber. Similarly, an axial magnetic flux is formed between the right end face of the piston disc 46 and the left end face of the annular partition 22, between the right end face of the annular partition 22 and the left end face of the piston disc 24, between the right end face of the piston disc 24 and the left end face of the annular partition 42, between the right end face of the annular partition 42 and the left end face of the piston disc 40, and between the right end face of the piston disc 40 and the left end face of the lower seat body 27. These magnetic fluxes will generate damping force on the movement of the piston disc 46, the piston disc 24 and the piston disc 40, which can reduce high-frequency small-amplitude vibration.

[0045] In addition, the upper seat body 19 is opposite to the cover plate 18 and a cavity 191 is formed therebetween. An oil hole 181 is provided on the cover plate 18. When the piston 11 moves toward the upper end cover 3, the magnetorheological fluid 10 in the cavity 191 between the upper seat body 19 and the cover plate 18 can flow into the rodless cavity of the piston 11 through the oil hole 181, thereby playing a role in fluid replenishment.

[0046] See also Figure 2 , Figure 3 and Figure 4 The circumferential surface of the piston 11 is a cylindrical outer surface, and the cylindrical outer surface of the right part has a plurality of axial long strip bosses 111. In this embodiment, four bosses 111 are provided. The top surface of the boss 111 fits the inner surface of the inner cylinder 56, so it can play an axial guiding role, ensuring that the entire piston 11 will not radially deviate from the central axis when moving left and right in the inner cylinder 56.

[0047] The structure of the present application is reasonable and feasible, and can solve the problem that the existing magnetorheological damper can only work in a single working mode and cannot take into account the vibration reduction of both low-frequency large-amplitude impact vibration and high-frequency small-amplitude vibration. In practice, many systems are manifested as small-amplitude high-frequency vibrations most of the time, and when they are started or suddenly disturbed by external disturbances, they will produce large-amplitude low-frequency impact vibrations. The present invention can effectively reduce the vibration of these systems with the above two types of vibrations.

[0048] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A dual-mode magnetorheological damper for vibration reduction, characterized in that: include: A large displacement shear damping part and a small displacement extrusion damping part are arranged along the length direction; The large displacement shear damping portion comprises a first piston rod (55), an inner cylinder (56) and an outer cylinder (57) which are sleeved in sequence from the inside to the outside, the inner end of the first piston rod (55) being sleeved with a piston (11), the inner cylinder (56) and the outer cylinder (57) being provided with a cover plate (18) at their ends facing the small displacement extrusion damping portion, and an upper end cover (3) at the other ends, the outer end of the first piston rod (55) passing through the upper end cover (3), the piston (11) being located in a space enclosed by the inner cylinder (56), the upper end cover (3) and the cover plate (18), and forming a gap with the inner wall of the inner cylinder (56); The small displacement extrusion damping part comprises a second piston rod (31) and an inner sleeve (38) which are sleeved in sequence from the inside to the outside, the inner sleeve (38) being sleeved with a first excitation coil (25), a plurality of piston discs being arranged along the length of the second piston rod (31), an upper seat body (19) being arranged at the end of the inner sleeve (38) facing the large displacement shear damping part, and a lower seat body (27) being arranged at the other end, a plurality of annular spacer discs being arranged on the inner wall along the length of the inner sleeve (38), and the piston discs and the annular spacer discs being arranged alternately.

2. A dual-mode magnetorheological damper for vibration reduction according to claim 1, characterized in that: A circular groove is formed in the middle of the piston (11) along the circumferential direction, and a second excitation coil (12) is installed in the circular groove.

3. A dual-mode magnetorheological damper for vibration reduction according to claim 2, characterized in that: A permanent magnet (53) is installed between the inner cylinder (56) and the outer cylinder (57) and at one end close to the cover plate (18).

4. The dual-mode magnetorheological damper for vibration reduction according to claim 1, characterized in that: The inner sleeve (38) is sleeved with an outer sleeve (39) to form a cavity between the inner sleeve (38), and the outer wall of the inner sleeve (38) forms an annular groove with the right end surface of the upper seat body (19) and the left end surface of the lower seat body (27), respectively, and the first excitation coil (25) is arranged in the annular groove.

5. A dual-mode magnetorheological damper for vibration reduction according to claim 4, characterized in that: Three piston discs are provided, and two annular spacer discs are provided. The annular spacer disc is located between two adjacent piston discs.

6. A dual-mode magnetorheological damper for vibration reduction according to any one of claims 1 to 5, characterized in that: An oil hole (181) is provided on the cover plate (18), and a cavity (191) is formed between the cover plate (18) and the upper seat body (19). When the piston (11) moves toward the side of the upper end cover (3), the magnetorheological fluid (10) in the cavity (191) between the upper seat body (19) and the cover plate (18) can flow into the rodless cavity of the piston (11) through the oil hole (181).

7. The dual-mode magnetorheological damper for vibration reduction according to claim 1, characterized in that: Both sides of the piston (11) are cylindrical outer surfaces, and four axially long strip-shaped bosses (111) are provided on the cylindrical outer surface of one side, and the bosses (111) are in close contact with the inner surface of the inner cylinder (56).

8. The dual-mode magnetorheological damper for vibration reduction according to claim 1, characterized in that: The second piston rod (31) is provided with a plurality of axial positioning sleeves, and the piston disc is arranged between two adjacent axial positioning sleeves.

9. The dual-mode magnetorheological damper for vibration reduction according to claim 1, characterized in that: A dust cover (58) is provided on one side of the outer cylinder (57) facing away from the small displacement extrusion damping portion.

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