A step-magnetorheological damper with fixed damping

Abstract

This invention discloses a step-variable electromagnetic rheodynamic damper with fixed damping, mainly composed of a double-rod piston, two sector-shaped pistons, a non-magnetic inner cylinder, and a magnetic inner cylinder. The gap between the two sector-shaped pistons forms a rectangular damping channel, and the gap between the sector-shaped pistons and the inner cylinder forms an annular damping channel. During piston movement, the step-variable damping force output from the annular damping channel compensates for part of the fixed damping force lost in the rectangular damping channel, thus achieving a step-variable Coulomb damping force output based on a constant fixed damping force output. This step-variable electromagnetic rheodynamic damper with fixed damping features simple structural design, strong targeting, and stable vibration reduction effect.

Description

Technical Field

[0001] The invention relates to a magnetorheological damping control technology, specifically a step-variable electromagnetic rheodynamic damper with a fixed damping force. Technical Background

[0002] Magnetorheological fluids consist of micron-sized magnetic particles dispersed in a base fluid such as silicone oil. Under the influence of an external magnetic field, the magnetic particles align sequentially along the magnetic field lines, causing the magnetorheological fluid to undergo a rheological effect and transform into a solid state. Magnetorheological dampers rely on the rheological properties of the magnetorheological fluid to output a specific damping force to achieve vibration reduction. Magnetorheological dampers have advantages such as simple structure, good stability, attitude recovery, high reliability, and strong controllability, and are currently widely used in automotive suspension systems, building structure vibration reduction, aerospace vehicle vibration reduction, and precision machining equipment vibration reduction.

[0003] The massive impact loads generated during heavy-load landings can cause irreversible mechanical damage to the carrier, and even lead to landing failures, seriously jeopardizing the safety of aerospace carrier landings. Magnetorheological dampers can mitigate such impact damage. However, traditional magnetorheological dampers rely on complex control systems to achieve variable damping output, which cannot meet the characteristics of high vibration energy and short impact duration during heavy-load landings. Patent CN106015437A utilizes changes in the damper cylinder material properties, setting both magnetically conductive and non-magnetically conductive inner cylinders to achieve adaptive variable damping output, but it cannot alleviate the sudden impact load at the initial stage of a heavy-load impact. To enable the magnetorheological damper to output a certain damping force at the initial stage of a heavy-load impact to mitigate the sudden impact load, a step-variable magnetorheological damper capable of outputting a fixed damping force is needed. Summary of the Invention

[0004] (a) Purpose of the invention

[0005] This invention proposes a step-variable electromagnetic rheodynamic damper that can provide a certain fixed damping force output, which solves the problem of impact damage to the device caused by the rapid increase in impact force in the early stage under high-speed and large impact conditions.

[0006] (II) Technical Solution

[0007] To address the technical problems arising from high-speed, high-impact situations, this invention provides a step-variable electromagnetic rheodynamic damper with fixed damping, comprising a double-rod piston rod, a threaded bushing, a sector piston, an excitation coil, a non-magnetic inner cylinder, a magnetic inner cylinder, a non-magnetic outer cylinder, a guide device, an end cap, a sealing ring, magnetorheological fluid, a nut, a power supply, screws, and a non-magnetic connecting plate. The non-magnetic and magnetic inner cylinders are smoothly and fixedly connected, with the magnetic inner cylinder positioned at the lower end of the non-magnetic outer cylinder within it. The area encompassed by the inner cylinder structure is filled with magnetorheological fluid. After winding around one sector piston, the excitation coil is led out from the threaded bushing and wound in the opposite direction onto a second sector piston. The two sector pistons and the non-magnetic connecting plate are connected and fixed by screws. The threaded bushing, sector piston, and guide device are sequentially mounted on the double-rod piston rod and fixedly connected by nuts. The excitation coil is led out through the inner hole of the double-rod piston and connected to the power supply.

[0008] The sector-shaped pistons used have multi-stage excitation coils, with the winding directions of the excitation coils on the two sector-shaped pistons opposite. The two sector-shaped pistons are made of magnetically conductive material and are fixedly connected by a non-magnetically conductive connecting plate. This connection method ensures a rectangular gap of a certain size between the two pistons. When the excitation coils are energized, the rectangular gap is filled with magnetic field lines when the piston structure is in any position within the inner cylinder, causing the magnetorheological fluid within the rectangular gap to exhibit a rheological effect and output a fixed damping force. When the upper part of the excitation coil on the piston enters the magnetically conductive inner cylinder region, the number of magnetic field lines in the rectangular gap decreases compared to the non-magnetically conductive inner cylinder region, while the number of magnetic field lines increases in the annular gap formed by the sector-shaped pistons and the magnetically conductive inner cylinder. This causes a rheological effect in the magnetorheological fluid in both the rectangular and annular gaps. Since the area of ​​the annular gap is larger than the area of ​​the rectangular gap, the step-change Coulomb damping force generated by the rheological effect of the magnetorheological fluid in the annular gap can compensate for the loss of fixed damping force in the rectangular gap after the piston enters the magnetically conductive inner cylinder region. The damper can continuously output a certain amount of fixed damping force during the vibration reduction process, and achieve step-variable Coulomb damping force output based on the fixed damping force to complete the target vibration reduction.

[0009] The two sector pistons and the non-magnetic connecting plate made of aluminum alloy are fixedly connected by screws.

[0010] The non-magnetic inner cylinder and the magnetic inner cylinder are arranged in sequence. The non-magnetic inner cylinder is made of non-magnetic material, such as aluminum alloy or nylon, while the magnetic inner cylinder is made of high magnetic permeability material, such as electrical pure iron or silicon steel.

[0011] The cross-sectional area of ​​the annular gap formed by the sector piston and the inner cylinder is larger than the cross-sectional area of ​​the rectangular gap between the two sector pistons.

[0012] The piston and piston rod assembly moves downward along the cylinder axis under the action of the guide device.

[0013] (III) Beneficial Effects

[0014] This invention provides a fixed damping force to mitigate the rapid and sudden impact force at the initial stage of high-speed impact vibration, reducing damage to the device. As the impact progresses, this invention outputs a certain amount of step-variable Coulomb damping force on top of the fixed damping force. This output step-variable Coulomb damping force mainly mitigates the gradually increasing impact force during the impact process. The step-variable electromagnetic rheodynamic damper with fixed damping proposed in this invention has a simple structure, high reliability, and low cost, and is mainly suitable for vibration reduction in high-speed, large-impact situations. Attached Figure Description

[0015] Figure 1 This is a three-dimensional structural diagram of the present invention.

[0016] In the diagram: 1. Double-rod piston rod; 2. Threading sleeve; 3. Sector piston; 4. Excitation coil; 5. Non-magnetic inner cylinder; 6. Magnetic inner cylinder; 7. Non-magnetic outer cylinder; 8. Guide device; 9. End cap; 10. Sealing ring; 11. Magnetorheological fluid; 12. Nut; 13. Power supply.

[0017] Figure 2 This is an isometric view of the piston structure.

[0018] In the diagram: Screw 14, Non-magnetic connecting plate 15

[0019] Figure 3 The graph shows the relationship between the output damping force of the rectangular damping channel and the output damping force of the annular damping channel and the piston stroke. Detailed Implementation

[0020] Figure 1 The present invention is a structural schematic diagram of the present invention, which is a step-variable electromagnetic rheodynamic damper with fixed damping, including a double-rod piston rod (1), a wire sleeve (2), a sector piston (3), an excitation coil (4), a non-magnetic inner cylinder (5), a magnetic inner cylinder (6), a non-magnetic outer cylinder (7), a guide device (8), an end cap (9), a sealing ring (10), a magnetorheological fluid (11), a nut (12), a power supply (13), a screw (14), and a non-magnetic connecting plate (15).

[0021] The non-magnetic inner cylinder (5) and the magnetic inner cylinder (6) are smoothly and fixedly connected with the magnetic inner cylinder (6) located at the lower end of the non-magnetic outer cylinder (7) and the non-magnetic inner cylinder (5) located at the upper end of the non-magnetic outer cylinder (7). Both the non-magnetic inner cylinder (5) and the non-magnetic outer cylinder (7) are made of aluminum alloy, and the magnetic inner cylinder (6) is made of electrical pure iron DT4. The sector piston (3) is made of electrical pure iron DT4. The excitation coil (4) is wound in an orderly manner on the sector piston (3). After being led out from the wire guide sleeve (2), it is wound with a multi-stage coil on another sector piston (3) in the opposite winding order. After connecting the two sector pistons (3) with screws (14) using a non-magnetic connecting plate (15), the combined structure of the wire guide sleeve (2) and the sector piston (3) is fixedly connected to the double-rod piston rod (1) by nuts (12) through the guide device (8). The excitation coil (4) is led out through the through hole on the double-rod piston rod (1) and connected to the power supply (13). The magnetorheological fluid (11) is located in the inner cylinder environment composed of the non-magnetic inner cylinder (5) and the magnetic inner cylinder (6).

[0022] When the sector piston (3) moves axially linearly within the inner cylinder environment composed of the non-magnetic inner cylinder (5) and the magnetic inner cylinder (6), the magnetorheological fluid (11) is filled with a certain pressure to fill the rectangular damping channel between the two sector pistons (3) and the annular damping channel between the sector piston (3) and the non-magnetic inner cylinder (5) and the magnetic inner cylinder (6). The damping channel between the two sector pistons (3) gives the damper a certain fixed damping force, and the damping channel between the sector piston (3) and the non-magnetic inner cylinder (5) and the magnetic inner cylinder (6) will output a Coulomb damping force on a certain fixed damping force. The power supply (13) inputs a constant current to the excitation coil (4). When the sector piston (3) is completely in the region of the non-magnetic inner cylinder (5), since the non-magnetic inner cylinder (5) is not magnetic, the excitation coil (4) cannot form a closed magnetic circuit in the annular damper channel between the non-magnetic inner cylinder (5) and the sector piston (3). Therefore, the rheological effect of the magnetorheological fluid (11) between the annular damping channels is not obvious and cannot generate step-variable damping force. The closed magnetic field lines generated by the excitation coils (4) on the two sector pistons (3) radially penetrate the rectangular damping channel between the two sector pistons (3), causing the magnetorheological fluid (11) in the rectangular damping channel to generate a strong rheological effect, generate a certain yield stress, and output a constant damping force. As the piston structure moves axially downward along the inner cylinder region, the excitation coils (4) on the sector pistons (3) enter the region of the magnetic inner cylinder (6) one by one and form corresponding magnetic field lines. Some of the magnetic field lines generated by the excitation coil (4) will pass through the magnetorheological fluid in the annular gap and form a loop with the magnetically conductive inner cylinder (6), resulting in a reduction in the magnetic field lines passing through the rectangular damping channel between the two sector pistons (3) in the region of the magnetically conductive inner cylinder (6). Since the cross-sectional area of ​​the annular gap between the non-magnetically conductive inner cylinder (5) and the magnetically conductive inner cylinder (6) and the sector pistons (3) is larger than the rectangular cross-section between the two sector pistons (3), the reduction in the fixed damping force output by the damper through the rectangular channel is compensated by the damping force output by the annular gap. As the stroke of the sector pistons (3) gradually descends, the number of closed magnetic circuits generated by the multi-stage excitation coil (4) increases, causing the magnetorheological damper to generate a sequentially accumulating Coulomb damping force. After the generated step-variable Coulomb damping force compensates for the loss of fixed damping force, there is still a certain step-like increase in Coulomb damping force.

[0023] The relationship between the fixed damping force and the step-variable Coulomb damping force of a step-variable electromagnetic rheostat with fixed damping and the downward stroke of the sector piston (3) is as follows: Figure 2 As shown, there are Figure 2 It can be seen that this damper can achieve a certain fixed damping force output and generate a certain step-like increase in Coulomb damping force as the fan-shaped piston (3) moves downward.

[0024] Based on the total damping force distribution of this magnetorheological damper, it can be seen that this damper can be applied to vibration reduction in high-speed, large-impact situations.

Claims

1. A step-damper magneto-rheological damper having a fixed damping, the damper comprising: Double-rod piston rod (1), wire sleeve (2), sector piston (3), excitation coil (4), non-magnetic inner cylinder (5), magnetic inner cylinder (6), non-magnetic outer cylinder (7), guide device (8), end cap (9), sealing ring (10), magnetorheological fluid (11), nut (12), power supply (13), screw (14), non-magnetic connecting plate (15). The above components are connected as follows: the non-magnetic inner cylinder (5) and the magnetic inner cylinder (6) are arranged in the order that the magnetic inner cylinder (6) is located at the lower end of the non-magnetic outer cylinder (7) and the non-magnetic inner cylinder (5) is located at the upper end of the non-magnetic outer cylinder (7). The non-magnetic inner cylinder (5) and the magnetic inner cylinder (6) contain magnetorheological fluid (11). The excitation coil (4) is wound in an orderly manner on the fan-shaped piston (3) and is connected in opposite directions through the wire sleeve (2). The winding direction is wound on the second sector piston (3) to complete the circuit series connection. The wire sleeve (2), sector piston (3) and guide device (8) are installed on the double rod piston rod (1) in sequence. The excitation coil (4) is led out through the inner hole of the double rod piston rod (1) and connected to the power supply (13). The bottom end of the double rod piston rod (1) is fixedly connected with a nut (12). The two sector pistons (3) are fixedly connected with screws (14) through the non-magnetic connecting plate (15). The feature is that when the fan-shaped piston (3) enters the piston cylinder structure composed of the non-magnetic inner cylinder (5), the magnetic inner cylinder (6), and the non-magnetic outer cylinder (7), a magnetic field is generated only in the gap between the two fan-shaped pistons (3) in the region of the non-magnetic inner cylinder (5), and an additional magnetized region that can grow in stages is generated in the region of the magnetic inner cylinder (6). The magnetorheological fluid (11) in the magnetized region generates a rheological effect after being magnetized, thereby realizing the step-variable damping force output with a certain fixed damping force and completing effective vibration reduction.

2. A step-variable magnetorheological damper with fixed damping according to claim 1, characterized in that... The wire sleeve (2) enables the two excitation coils (4) with opposite winding directions on the two fan-shaped pistons (3) arranged in parallel to achieve circuit series connection. The piston structure consists of five parts: double-rod piston rod (1), wire sleeve (2), fan-shaped piston (3), excitation coil (4) and non-magnetic connecting plate (15).

3. A step-variable magnetorheological damper with fixed damping according to claim 1, characterized in that... A DC power supply can be input to the excitation coil (4) through the power supply (13) to generate a certain magnetic field in the gap between the two parallel sector pistons (3).

4. A step-variable magnetorheological damper with fixed damping according to claim 1, characterized in that... Two parallel sector pistons (3) are fixedly connected by a non-magnetic connecting plate (15).

5. A step-variable magnetorheological damper with fixed damping according to claim 1, characterized in that... The non-magnetic inner cylinder (5) and the magnetic inner cylinder (6) are arranged in sequence. The non-magnetic inner cylinder (5) is made of non-magnetic material, and the magnetic inner cylinder (6) is made of high magnetic permeability material.

6. A step-variable magnetorheological damper with fixed damping according to claim 1, characterized in that... The cross-sectional area of ​​the annular gap between the non-magnetic inner cylinder (5) and the magnetic inner cylinder (6) and the sector piston (3) is larger than the rectangular cross-section between the two sector pistons (3).

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