Magnetorheological damper with fast response characteristics

Abstract

The application belongs to the technical field of magneto-fluid damper, and particularly discloses a magneto-rheological damper with quick response characteristic, which comprises a cylinder body and a piston rod, a piston head is vertically and slidably arranged in the cylinder body, a damping passage gap is formed between the piston head and the side wall of the cylinder body, the piston head comprises a sleeve and a magnetic core, the magnetic core comprises a plurality of magnetically conductive sheets which are connected with each other and sequentially connected along the circumference of the sleeve, a winding groove is formed in the magnetically conductive sheet, the piston rod is inserted into the cylinder body and coaxially connected with the sleeve, the chambers above and below the piston head are working chambers, and the working chambers are filled with magneto-rheological fluid. The application can effectively solve the time lag caused by the eddy current effect hindering the rise of the magnetic field strength in the damping passage, and improve the response speed of the magneto-rheological damper.

Description

Technical Field

[0001] This invention relates to the field of magnetorheological damper technology, and more specifically to a magnetorheological damper with fast response characteristics. Background Technology

[0002] A magnetorheological damper is a device that achieves damping by altering the flow characteristics of a magnetorheological fluid. It features continuously adjustable damping force, a wide adjustment range, and fast response. As a semi-active vibration reduction device, it is frequently used in aerospace, automotive suspension, and building vibration reduction. However, due to the extremely short duration of the impact process in a magnetorheological damper, the response speed becomes a key indicator affecting its performance. The response time of a magnetorheological damper can be approximately divided into three parts: current response time, magnetic field response time, and magnetorheological fluid response time.

[0003] Among the factors affecting the response speed of a magnetorheological damper, the magnetic field response time, specifically the lag time caused by the eddy current effect of the magnetic circuit material hindering the rise of the magnetic field strength within the damping channel, is the most significant factor. Therefore, to improve the response speed, the influence of the eddy current effect must be reduced. In traditional magnetorheological damper structures, the piston head is typically designed as a uniformly shaped cylinder. This design results in a shorter path for eddy current formation, leading to a larger eddy current effect when the magnetic field strength changes, thus reducing the response speed of the magnetorheological damper. Summary of the Invention

[0004] This invention provides a magnetorheological damper with fast response characteristics, aiming to solve the time lag caused by the eddy current effect hindering the rise of magnetic field strength in the damping channel, and improve the response speed of the magnetorheological damper.

[0005] This invention is achieved through the following technical solution: a magnetorheological damper with fast response characteristics, comprising a cylinder and a piston rod, wherein a piston head is vertically slidably mounted in the cylinder, and a damping channel gap is formed between the piston head and the side wall of the cylinder, the piston head comprising a sleeve and a magnetic core, the magnetic core comprising a plurality of interconnected magnetic conductive plates, and the plurality of magnetic conductive plates are sequentially connected along the circumference of the sleeve, the magnetic conductive plates having winding grooves formed on the magnetic conductive plates, the piston rod being inserted into the cylinder and coaxially connected to the sleeve; the chambers above and below the piston head are both working chambers, and the working chambers are filled with magnetorheological fluid.

[0006] Compared with existing technologies, this invention has the following advantages and beneficial effects: The magnetic core of the magnetorheological damper of this invention adopts a stacked magnetic circuit structure, and these magnetic sheets form a continuous magnetic circuit path. Eddy currents flow along the edge paths between the magnetic sheets, and this magnetic sheet structure increases the eddy current path. At this time, the eddy currents need to overcome a larger resistance value to form a closed loop, which significantly reduces the eddy currents and rapidly increases the magnetic field strength of the damping channel, thereby improving the response speed of the magnetorheological damper.

[0007] Furthermore, the magnetic conductive sheet is a fan-shaped magnetic conductive sheet. Eddy currents flow along the edge path of the fan shape between the fan-shaped magnetic conductive sheets, and this fan-shaped magnetic conductive sheet structure increases the eddy current path.

[0008] Furthermore, the magnetic conductive sheet includes multiple sets of long fan-shaped magnetic conductive sheets and multiple short fan-shaped magnetic conductive sheets. The multiple sets of long fan-shaped magnetic conductive sheets are evenly distributed circumferentially on the outer side of the sleeve. The multiple short fan-shaped magnetic conductive sheets are sequentially overlapped circumferentially between adjacent long fan-shaped magnetic conductive sheets. The length of the long fan-shaped magnetic conductive sheets is greater than the length of the short fan-shaped magnetic conductive sheets. The sleeve is I-shaped, and multiple limiting grooves are formed at both the top and bottom ends of the sleeve. The multiple limiting grooves are evenly distributed circumferentially along the sleeve, and the number of limiting grooves is the same as the number of sets of long fan-shaped magnetic conductive sheets. The top and bottom ends of the long fan-shaped magnetic conductive sheets can be inserted into the limiting grooves at the top and bottom ends of the sleeve, respectively. In this design, the long fan-shaped magnetic conductive sheets can cooperate with the limiting grooves to play a role in installation and positioning, which can enhance the stability of the entire piston head structure.

[0009] Furthermore, a floating piston is provided at the lower part of the cylinder body. The chamber below the floating piston is a compensation chamber, and the chamber between the floating piston and the piston head, as well as the chamber between the piston head and the cylinder body, are working chambers. The compensation chamber is filled with nitrogen. In this design, the piston head and the floating piston divide the accommodating chambers within the cylinder body into three parts: one compensation chamber and two working chambers. The compensation chamber is filled with high-pressure nitrogen to compensate for volume changes within the cylinder body caused by the up-and-down movement of the piston rod. The two working chambers are filled with magnetorheological fluid. When the magnetorheological damper is subjected to an impact load, the piston rod moves downward, causing the piston head to compress the magnetorheological fluid, which flows from one working chamber to the other. The energy absorption characteristics of the magnetorheological damper can be adjusted by controlling the magnitude of the current.

[0010] Furthermore, sealing rings are provided between the cylinder body and the piston rod, as well as between the cylinder body and the floating piston. The sealing rings in this design ensure a tight seal between the piston rod and the floating piston and the cylinder body.

[0011] Furthermore, the piston rod includes a front section and a rear section coaxially connected. The rear section has external threads, and the sleeve has a threaded hole in its center along its axial direction. The rear section is threadedly connected to the threaded hole of the sleeve. In this design, the piston rod is threadedly connected to the sleeve via its rear section, which is simpler, more convenient, and easier to disassemble.

[0012] Furthermore, a central hole is coaxially formed on the piston rod, and the central hole is a through hole structure. In this design, the coil wire can be led out through the central hole of the piston rod.

[0013] Furthermore, the magnetic conductive sheet has multiple winding slots, which are spaced apart along the length of the magnetic conductive sheet. In this design, the excitation coil can be tightly wound within the three winding slots of the magnetic conductive sheet, which can fix the magnetic conductive sheet and increase the stability and rigidity of the overall piston head structure.

[0014] Furthermore, a buffer pad is connected to the top wall of the cylinder. In this design, the buffer pad is used to prevent rigid collisions between the piston head and the cylinder.

[0015] Furthermore, the bottom of the cylinder is an open end, and a screw cap is detachably connected to the bottom of the cylinder, with a sealing gasket between the screw cap and the bottom of the cylinder. The screw cap in this design facilitates the installation or removal of the piston head from the cylinder, while the sealing gasket ensures the cylinder's airtightness. Attached Figure Description

[0016] The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and form part of this application, do not constitute a limitation thereof. In the drawings:

[0017] Figure 1 This is a longitudinal cross-sectional view of an embodiment of a magnetorheological damper with fast response characteristics according to the present invention.

[0018] Figure 2 This is a cross-sectional view of an embodiment of a magnetorheological damper with fast response characteristics according to the present invention.

[0019] Figure 3 This is a perspective view of the magnetic core in an embodiment of a magnetorheological damper with fast response characteristics according to the present invention.

[0020] Figure 4 This is a perspective view of a magnetorheological damper embodiment with fast response characteristics according to the present invention, showing the interconnection of a long sector magnetic sheet and a short sector magnetic sheet.

[0021] Figure 5 This is a perspective view of the sleeve in an embodiment of a magnetorheological damper with fast response characteristics according to the present invention.

[0022] Figure 6 This is the step response of the magnetic field strength increase in this invention;

[0023] Figure 7 This is the step response of the magnetic field strength decrease in this invention.

[0024] The attached diagram shows the markings and corresponding component names:

[0025] 1. Cylinder body; 2. Piston head; 3. Excitation coil; 4. Piston rod; 4. Front rod section 401; 4. Rear rod section 402; 4. Center hole 403; 5. Working chamber; 6. Floating piston; 7. Compensation chamber; 8. Sealing ring; 9. Buffer pad; 10. Sealing gasket; 11. Screw cap; 12. Sleeve; 121. Threaded hole; 13. Magnetic core; 14. Long fan-shaped magnetic conductor; 15. Short fan-shaped magnetic conductor; 16. Limiting groove. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0027] like Figures 1-5 As shown, this embodiment provides a magnetorheological damper with fast response characteristics, including a cylinder 1 and a piston rod 4. The cylinder 1 is a hollow cylinder with a hollow interior. A piston head 2 is vertically slidably installed inside the cylinder 1. In this embodiment, the bottom of the cylinder 1 is an open end, and a screw cap 11 is detachably connected to the open end of the bottom of the cylinder 1. In this embodiment, the screw cap 11 is threadedly connected to the bottom of the cylinder 1, forming a sealed receiving cavity between the screw cap 11 and the cylinder 1. A sealing gasket 10 is provided between the screw cap 11 and the cylinder 1 to ensure the sealing of the cylinder 1. The cooperation between the screw cap 11 and the cylinder 1 allows the bottom of the cylinder 1 to be opened or closed, thereby facilitating the installation or removal of the piston head 2, making it more practical.

[0028] A damping channel gap is formed between the piston head 2 and the side wall of the cylinder 1. The piston head 2 includes a sleeve 12 and a magnetic core 13. The magnetic core 13 is installed on the outside of the sleeve 12. The magnetic core 13 includes multiple interconnected magnetic sheets, and the multiple magnetic sheets are connected sequentially along the circumference of the sleeve 12. In this embodiment, the multiple magnetic sheets are formed by overlapping and bonding them sequentially in the circumferential direction with insulating glue. The magnetic sheets are provided with winding grooves. In this embodiment, each magnetic sheet is provided with three winding grooves, and the three winding grooves are distributed at intervals along the length direction of the magnetic sheet.

[0029] In this embodiment, a central hole 403 is coaxially provided on the piston rod 4, and the central hole 403 is a through hole structure. In this embodiment, after the coil wire is wound on the winding groove, it can be led out through the central hole 403 of the piston rod 4, so that the wire is more neat and avoids being messy in the cylinder 1.

[0030] Combining 3, Figure 4 and Figure 5 As shown, the magnetic conductive sheet in this embodiment is a fan-shaped magnetic conductive sheet, and the magnetic conductive sheet includes multiple sets of long fan-shaped magnetic conductive sheets 14 and multiple short fan-shaped magnetic conductive sheets 15. The multiple sets of long fan-shaped magnetic conductive sheets 14 are evenly distributed circumferentially on the outside of the sleeve 12, and the multiple short fan-shaped magnetic conductive sheets 15 are sequentially and circumferentially overlapped between adjacent long fan-shaped magnetic conductive sheets 14. The length of the long fan-shaped magnetic conductive sheets 14 is greater than the length of the short fan-shaped magnetic conductive sheets 15, and both ends of the long fan-shaped magnetic conductive sheets 14 extend beyond the two ends of the short fan-shaped magnetic conductive sheets 15. Figure 3 As shown, in this embodiment, there are four sets of long fan-shaped magnetic sheets 14. The four sets of long fan-shaped magnetic sheets 14 are evenly distributed around the circumference, and each set of long fan-shaped magnetic sheets includes two interconnected long fan-shaped magnetic sheets 14.

[0031] Combination Figure 5 As shown, the sleeve 12 is I-shaped, with four limiting grooves 16 at both the top and bottom. The four limiting grooves 16 are evenly distributed along the circumference of the sleeve 12. In this embodiment, the number of limiting grooves 16 is the same as the number of sets of long fan-shaped magnetic sheets 14, and the shape of the limiting grooves 16 matches the shape and size of each set of long fan-shaped magnetic sheets 14. In this way, the top and bottom of the four sets of long fan-shaped magnetic sheets 14 can be inserted into the limiting grooves 16 at the top and bottom of the sleeve 12, respectively, to play a positioning role. Multiple short fan-shaped magnetic sheets 15 are sequentially filled between two adjacent sets of long fan-shaped magnetic sheets 14 and are connected and fixed to each other to form a columnar structure. The two types of fan-shaped magnetic sheets are provided with winding grooves of the same size and in the same position.

[0032] The piston rod 4 is inserted into the cylinder body 1 and coaxially connected to the sleeve 12. In this embodiment, the piston rod 4 includes a front rod body 401 and a rear rod body 402 coaxially connected. The rear rod body 402 is provided with external threads, and the diameter of the rear rod body 402 is smaller than the diameter of the front rod body 401. A threaded hole 121 is opened in the center of the sleeve 12 along its axial direction. The rear rod body 402 of the piston rod 4 is threadedly connected to the threaded hole 121 of the sleeve 12, thereby realizing a detachable connection between the piston rod 4 and the sleeve 12. In this embodiment, a sealing ring 8 is provided between the cylinder body 1 and / or the piston rod 4. Figure 1 As shown, a sealing ring 8 is provided between the front section 401 of the piston rod 4 and the upper part of the cylinder 1, thereby ensuring the sealing of the cylinder 1.

[0033] The chambers above and below the piston head 2 are both working chambers 5, and both working chambers 5 are filled with magnetorheological fluid. In this embodiment, a buffer pad 9 is connected to the top wall of the cylinder 1, that is, a buffer pad 9 is installed on the top wall of the working chamber 5 above the piston head 2. In this solution, the buffer pad 9 can be used to prevent rigid collisions between the piston head 2 and the cylinder 1, thereby extending the service life of the piston head 2 and the cylinder 1. In this embodiment, the buffer pad 9 is a polyurethane buffer pad 9.

[0034] In another embodiment, a floating piston 6 is provided at the lower part of the cylinder body 1. In this embodiment, the outer diameter of the floating piston 6 matches the inner diameter of the cylinder body 1 to ensure that the floating piston 6 can move freely up and down inside the cylinder body 1.

[0035] The chamber below the floating piston 6 is the compensation chamber 7. The chamber between the floating piston 6 and the piston head 2, and the chamber between the piston head 2 and the cylinder 1 are the working chambers 5. In this embodiment, a sealing ring 8 is also provided between the floating piston 6 and the cylinder 1. The sealing ring can ensure the sealing of the compensation chamber 7 and the working chamber 5.

[0036] The compensation chamber 7 is filled with high-pressure nitrogen to compensate for the volume change in the cylinder 1 caused by the up-and-down movement of the piston rod 4. The purpose of filling the compensation chamber 7 with high-pressure nitrogen is to compensate for the volume change in the working cylinder 1 caused by the up-and-down movement of the piston rod 4. When the piston rod 4 moves down or up, the volume of the working chamber 5 will decrease or increase accordingly, and the high-pressure nitrogen filling the compensation chamber 7 can withstand this volume change.

[0037] High-pressure nitrogen acts as an elastic reservoir in the compensation chamber 7. When the piston rod 4 moves downward, the volume of the working chamber 5 decreases, causing the pressure within the working chamber 5 to increase. Simultaneously, the high-pressure nitrogen is also affected by the increased pressure. Because the compensation chamber 7 is connected to the working chamber 5, the elastic properties of the high-pressure nitrogen allow it to withstand the pressure changes caused by the volume change of the working chamber 5, thereby stabilizing the system pressure.

[0038] When piston rod 4 moves upward, the volume of working chamber 5 increases, which leads to a decrease in pressure within working chamber 5. At the same time, high-pressure nitrogen gas is also affected by the decrease in pressure, but its elastic properties allow it to release the stored energy to maintain the system pressure balance.

[0039] By using high-pressure nitrogen gas in the compensation chamber 7, the volume change of the working chamber 5 caused by the up-and-down movement of the piston rod 4 can be effectively compensated, ensuring that the system maintains stable pressure and performance during operation. Both working chambers 5 are filled with magnetorheological fluid. When the magnetorheological damper is subjected to an impact load, the piston rod 4 moves downward, causing the piston head 2 to compress the magnetorheological fluid, causing it to flow from one working chamber 5 to the other. The energy absorption characteristics of the magnetorheological damper can be adjusted by controlling the magnitude of the current.

[0040] In this invention, the excitation coil 3 is tightly wound within the winding groove of the sector-shaped magnetic sheet. The wire of the excitation coil 3 is led out through the central hole of the piston rod 4. On one hand, the excitation coil 3 adopts a three-stage parallel coil configuration, which can increase the effective damping channel length of the magnetorheological damper and reduce the response time of the excitation current. On the other hand, by tightly winding the excitation coil 3 within the winding groove of the sector-shaped magnetic sheet, the excitation coil 3 serves to fix the sector-shaped magnetic sheet, increasing its structural stability and rigidity.

[0041] The specific implementation process is as follows: During the operation, in the rising phase of the magnetic field strength, the changing magnetic field excites eddy currents in the magnetic circuit structure. The magnetic field generated by the eddy currents then hinders the rise of the original magnetic field, ultimately causing magnetic field hysteresis. When an excitation current is applied to the excitation coil 3, the magnetic field lines will form a closed loop through the magnetic core 13, the magnetorheological fluid, the cylinder 1, the magnetorheological fluid, and the magnetic core. The eddy current effect in the magnetic core 13 and the cylinder 1 will cause the magnetic field in the damping channel to hysteresis.

[0042] The magnetic core 13 is composed of multiple circumferentially overlapping and fixed sector-shaped magnetic sheets, which form a continuous magnetic circuit path. Eddy currents flow along the edge path of the sector between the magnetic sheets, and this sector-shaped magnetic sheet structure increases the eddy current path. At this time, the eddy currents need to overcome a larger resistance value to form a closed loop, which significantly reduces the eddy currents and causes the magnetic field strength of the damping channel to rise rapidly, thereby improving the response speed of the magnetorheological damper.

[0043] like Figure 6 The figure shows the step response of the magnetic field strength increase of the present invention; Figure 7 This is the step response of the magnetic field strength decrease in this invention. For example... Figure 6 and Figure 7 As shown, simulation analysis was performed using finite element simulation components. Compared with traditional magnetorheological dampers, the sector-shaped magnetorheological damper of this invention reduces the response time by 86.81% under rising edge excitation and by 85.51% under falling edge excitation. Simulation results show that the magnetorheological damper using a sector-shaped stacked magnetic circuit structure can effectively improve the response speed of the magnetorheological damper.

[0044] In this embodiment, the applied excitation current peak value is 3A, and the rise and fall response times are 6ms. Here, the response time is the time required for the applied excitation current to rise to 95% of its peak value or fall to 5% of its peak value.

[0045] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A magnetorheological damper with fast response characteristics, comprising a cylinder and a piston rod, characterized in that, A piston head is vertically slidably mounted inside the cylinder, forming a damping channel gap between the piston head and the side wall of the cylinder. The piston head includes a sleeve and a magnetic core. The magnetic core includes multiple interconnected magnetic conductive plates, which are sequentially connected along the circumference of the sleeve. Winding grooves are formed on the magnetic conductive plates. The piston rod is inserted into the cylinder and coaxially connected to the sleeve. The chambers above and below the piston head are both working chambers, each filled with magnetorheological fluid. The magnetic conductive plates are fan-shaped, comprising multiple sets of long fan-shaped magnetic conductive plates. The sleeve comprises a single sheet and multiple short fan-shaped magnetic sheets, and multiple sets of long fan-shaped magnetic sheets are evenly distributed circumferentially on the outside of the sleeve. The multiple short fan-shaped magnetic sheets are sequentially overlapped circumferentially between adjacent long fan-shaped magnetic sheets. The length of the long fan-shaped magnetic sheets is greater than the length of the short fan-shaped magnetic sheets. The sleeve is I-shaped, and multiple limiting grooves are provided at both the top and bottom of the sleeve. The multiple limiting grooves are evenly distributed circumferentially along the sleeve, and the number of limiting grooves is the same as the number of sets of long fan-shaped magnetic sheets. The top and bottom of the long fan-shaped magnetic sheets can be inserted into the limiting grooves at the top and bottom of the sleeve, respectively.

2. A magnetorheological damper with fast response characteristics according to claim 1, characterized in that, The lower part of the cylinder is provided with a floating piston. The chamber below the floating piston is a compensation chamber. The chamber between the floating piston and the piston head and the chamber between the piston head and the cylinder are working chambers. The compensation chamber is filled with nitrogen.

3. A magnetorheological damper with fast response characteristics according to claim 2, characterized in that, A sealing ring is provided between the cylinder and the piston rod, and between the cylinder and the floating piston.

4. A magnetorheological damper with fast response characteristics according to claim 1, characterized in that, The piston rod includes a front rod body and a rear rod body that are coaxially connected. The rear rod body is provided with external threads. The sleeve has a threaded hole in the center along its axial direction. The rear rod body is threadedly connected to the threaded hole of the sleeve.

5. A magnetorheological damper with fast response characteristics according to claim 1, characterized in that, The piston rod has a central hole coaxially formed on it, and the central hole is a through hole structure.

6. A magnetorheological damper with fast response characteristics according to claim 1, characterized in that, The magnetic sheet has multiple winding slots, which are spaced apart along the length of the magnetic sheet.

7. A magnetorheological damper with fast response characteristics according to claim 1, characterized in that, The top wall of the cylinder is connected to a buffer pad.

8. A magnetorheological damper with fast response characteristics according to claim 1, characterized in that, The bottom of the cylinder is an open end, and a screw cap is detachably connected to the bottom of the cylinder, with a sealing gasket between the screw cap and the bottom of the cylinder.

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