Oil magnetohydrodynamic damper

Abstract

This invention discloses an oil-based magnetorheological damper, comprising a cylinder, a floating separator piston, and a piston rod. A magnetorheological slide valve piston mechanism is slidably connected within the oil chamber. The lower end of the piston rod extends from the top cover into the cylinder and is fixedly connected to the magnetorheological slide valve piston mechanism. The magnetorheological slide valve piston mechanism includes a magnetorheological piston, a piston seat, a slide valve core, an excitation coil, and a piston outer body. This oil-based magnetorheological damper allows for damping adjustment without replacing the hydraulic oil, primarily due to its internal magnetorheological slide valve piston mechanism. Compared to magnetorheological dampers that replace hydraulic oil, it significantly improves upon the shortcomings of traditional magnetorheological shock absorbers. Furthermore, it greatly reduces uncontrollable factors in damping adjustment, as only a small amount of magnetorheological fluid is present inside the slide valve core, making control relatively simple. Compared to dampers where the entire cylinder is filled with magnetorheological fluid, the new damper has a smaller excitation current and a more flexible response.

Description

Technical Field

[0001] This invention relates to the field of damper technology, and more particularly to oil magnetohydrodynamic dampers. Background Technology

[0002] Most shock absorbers used in automotive suspension systems on the market are hydraulic shock absorbers. Their principle is that when the piston reciprocates within the shock absorber cylinder, the oil inside the cylinder constantly shuttles between the piston and various valves, creating a damping force through friction with the inner wall and the internal friction between liquid molecules. This process primarily relies on friction and damping to absorb and convert impact energy. The damping produced by this type of shock absorber, which uses hydraulic oil as the damping medium, is uncontrollable. For passengers to achieve a more comfortable ride, the "softness" or "stiffness" of the car's suspension system must be able to respond promptly to different driving conditions and road conditions. Therefore, shock absorbers with variable damping, such as magnetorheological dampers, have been developed. The biggest difference between magnetorheological dampers and traditional hydraulic dampers is that the damping medium in a magnetorheological damper is replaced by a magnetorheological fluid, and an electromagnetic system is added. A simplified schematic diagram of an existing magnetorheological damper is shown below. Figure 1 As shown, the working principle of the magnetorheological damper is that when the current in the excitation coil 02 increases, the magnetic field inside the throttling orifice strengthens, and the resistance of the magnetorheological fluid 03 flowing through the orifice increases accordingly, thus increasing the damping force output by the damper. Conversely, when the current decreases, the damping force also decreases. Therefore, the magnitude of the damping force can be controlled by adjusting the input current. Combined with the vehicle's driving system, the suspension damping can adapt to road conditions to achieve the optimal shock absorption effect. In summary, it is easy to see that because magnetorheological fluids are less lubricating than hydraulic oils, their flow resistance is much higher, which can negatively impact the lifespan of valves, seals, and components subject to friction. Furthermore, since the magnetic field of the excitation coil cannot be completely confined between piston 01 and the throttle orifice, the magnetorheological fluid outside piston 01 will also exhibit varying degrees of solidification. This results in poor damping linearity of the shock absorber, indicating too many uncontrollable factors related to the external magnetorheological fluid. Additionally, when the magnetorheological fluid inside the cylinder remains stationary for extended periods, magnetic particles will deposit and may even solidify, significantly reducing the shock absorber's damping effect. Summary of the Invention

[0003] To overcome the shortcomings of the prior art, the purpose of this invention is to provide an oil magnetohydrodynamic damper that is relatively simple to control and has a flexible response.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] The oil magnetohydrodynamic damper includes a cylinder, a floating separator piston, and a piston rod. The bottom and top of the cylinder are respectively fixed with a bottom end cap and a top end cap. The floating separator piston is slidably sleeved inside the cylinder. The space inside the cylinder from the floating separator piston to the bottom end cap is a gas chamber containing gas at a certain pressure. The space inside the cylinder from the floating separator piston to the top end cap is an oil chamber filled with hydraulic oil.

[0006] A magnetic flow valve piston mechanism is slidably connected in the oil chamber, and the lower end of the piston rod extends from the top cover into the cylinder body and is fixedly connected to the magnetic flow valve piston mechanism.

[0007] The magnetohydrodynamic slide valve piston mechanism includes a magnetohydrodynamic piston, a piston seat, a slide valve core, an excitation coil, and a piston outer body;

[0008] The piston outer body is slidably connected to the inside of the cylinder body, the piston seat is fixedly connected to the inside of the piston outer body, the excitation coil is fixedly connected to the annular groove on the outer circular wall of the piston seat, and piston end caps are fixed to the two shaft ends of the piston seat respectively, and the two piston end caps have hollow holes for hydraulic oil to pass through.

[0009] The spool valve core is slidably sleeved on the inner hole of the piston seat. Multiple annular plates are spaced along the axial direction on the outer circumferential wall of the spool valve core. Multiple flow holes are spaced along the circumferential direction on each annular plate. Two annular groove-shaped valve ports are spaced along the axial direction on the inner hole of the piston seat. Multiple flow channels are spaced along the circumferential direction on the two axial end faces of the piston seat. Each flow channel at the two axial ends is connected to the valve port on the corresponding side. When the spool valve core moves along the axial direction, it can change the opening degree of the valve port.

[0010] The two ends of the slide valve core are respectively fixed with sealing end caps, and the slide valve core is filled with magnetorheological fluid.

[0011] The magnetic flux piston has an annular portion in the middle, and multiple throttling holes are spaced along the circumferential direction on the outer peripheral wall of the annular portion. The magnetic flux piston is slidably sleeved with the sealing end caps at both ends of the slide valve core, and the annular portion of the magnetic flux piston is located inside the slide valve core. A retaining ring is fixed on each end of the magnetic flux piston, and a return spring sleeved on the magnetic flux piston is connected between the retaining rings at both ends and the sealing end caps on the corresponding sides. A clamping seat is slidably sleeved on each end of the magnetic flux piston. The clamping seat at one end is sleeved on the piston rod end, and the clamping seat at the other end is sleeved in the piston end cap on the corresponding side. A safety spring sleeved on the magnetic flux piston is connected between the two clamping seats and the retaining rings on the corresponding sides.

[0012] Furthermore, the outer ring of the piston body is provided with a combined sealing ring, which is used for dynamic sealing during the sliding of the piston body along the inside of the cylinder.

[0013] Furthermore, the sealing end cap is provided with a Glyd ring that fits onto the magnetohydrodynamic piston.

[0014] Furthermore, push covers are fixed on the sealing end caps at both ends of the magnetic flux piston, and the push covers are abutted against the corresponding reset springs.

[0015] Furthermore, an adjusting screw is threaded onto the piston end cap at the end furthest from the piston rod, and the end of the adjusting screw rests against the corresponding clamping seat.

[0016] The above technical solution offers the following beneficial effects: The oil-based magnetorheological damper of this invention can change its damping without replacing the hydraulic oil, primarily due to its internal magnetorheological slide valve piston mechanism. Compared to magnetorheological dampers that replace hydraulic oil, it significantly improves upon the shortcomings of traditional magnetorheological dampers. Furthermore, it greatly reduces uncontrollable factors in damping adjustment, as only a small amount of magnetorheological fluid is present inside the slide valve core, making control relatively simple. Compared to dampers where the entire cylinder is filled with magnetorheological fluid, the new damper has a smaller excitation current and more flexible response. Components such as those on the magnetorheological slide valve piston mechanism and the seals on the end caps can be interchangeable with those of traditional dampers because its damping medium is still hydraulic oil, resulting in better linear damping. Attached Figure Description

[0017] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments;

[0018] Figure 1 A simplified schematic diagram of the magnetorheological fluid damper in the existing technology;

[0019] Figure 2 This is a cross-sectional view of the oil magnetohydrodynamic damper of the present invention;

[0020] Figure 3 This is a cross-sectional view of the piston mechanism of the magnetohydrodynamic slide valve.

[0021] Figure 4 This is a schematic diagram of the piston seat.

[0022] Figure 5 This is a schematic diagram of the spool valve core;

[0023] Figure 6 A schematic diagram showing the flow of oil between the piston seat and the spool valve. Implementation

[0024] like Figure 2-6As shown, the oil magnetohydrodynamic damper of the present invention includes a cylinder body 1, a floating separator piston 2 and a piston rod 3. The bottom and top of the cylinder body 1 are respectively fixed with a bottom end cover 4 and a top end cover 5. The floating separator piston 2 is slidably sleeved inside the cylinder body 1. The internal space of the cylinder body 1 from the floating separator piston 2 to the bottom end cover 4 is a gas chamber containing gas at a certain pressure. The internal space of the cylinder from the floating separator piston 2 to the top end cover 5 is an oil chamber for filling with hydraulic oil.

[0025] A magnetic flow valve piston mechanism 6 is slidably connected in the oil chamber. The lower end of the piston rod 3 extends from the top cover 5 into the cylinder body 1 and is fixedly connected to the magnetic flow valve piston mechanism 6. The magnetic flow valve piston mechanism 6 divides the oil chamber into an upper chamber (rod chamber) and a lower chamber (rodless chamber). During the up-and-down vibration of the magnetic flow valve piston mechanism 6, the presence of the piston rod 3 will cause a certain volume difference between the upper and lower chambers. This volume difference is mainly compensated and eliminated by the up-and-down movement of the floating separator piston 2 to compress the air chamber.

[0026] The magnetohydrodynamic slide valve piston mechanism 6 includes a magnetohydrodynamic piston 61, a piston seat 62, a slide valve core 63, an excitation coil 64, and a piston outer body 65;

[0027] The piston outer body 65 is slidably connected to the inside of the cylinder body 1. The outer ring of the piston outer body 65 is provided with a combined sealing ring 6501. During the sliding process of the piston outer body 65 along the inside of the cylinder body 1, the combined sealing ring 6501 is used for dynamic sealing. The piston seat 62 is fixedly connected to the inside of the piston outer body 65. The excitation coil 64 is fixedly connected to the annular groove on the outer circular wall of the piston seat 62. Piston end caps 66 are fixed to the two shaft ends of the piston seat 62 respectively. The two piston end caps 66 are respectively provided with hollow holes for hydraulic oil to pass through.

[0028] The spool valve core 63 is slidably sleeved on the inner hole of the piston seat 62. Multiple annular plates 6301 are spaced axially on the outer circumferential wall of the spool valve core 63, and multiple flow holes 6302 are spaced circumferentially on each annular plate 6301. Two annular groove-shaped valve ports 6201 are spaced axially on the inner hole of the piston seat 62. Multiple flow channels 6202 are spaced circumferentially on the two axial end faces of the piston seat 62, and each flow channel 6202 at the two axial ends communicates with the corresponding valve port 6201. When the spool valve core 63 moves axially, it can change the opening degree of the valve port 6201. The larger the opening degree of the valve port 6201, the smaller the damping, and vice versa.

[0029] The two ends of the slide valve core 63 are respectively fixed with sealing end caps 67, and the slide valve core 63 is filled with magnetorheological fluid.

[0030] The magnetic flux piston 61 has an annular portion 6101 in the middle. Multiple throttling holes 6102 are spaced circumferentially on the outer peripheral wall of the annular portion 6101. The magnetic flux piston 61 is slidably sleeved with the sealing end caps 67 at both ends of the spool valve core 63 (the sealing end caps 67 are equipped with Gladley rings fitted onto the magnetic flux piston 61), and the annular portion 6101 of the magnetic flux piston 61 is located inside the spool valve core 63. Retaining rings 68 are fixed to both ends of the magnetic flux piston 61 (using threaded connections). A return spring 69 is sleeved on the magnetic flux piston 61 between the retaining rings 68 at both ends and the sealing end caps 67 on the corresponding side; a clamping seat 610 is slidably sleeved at both ends of the magnetic flux piston 61, one end of the clamping seat 610 is sleeved on the end of the piston rod 3, and the other end of the clamping seat 610 is sleeved in the piston end cap 66 on the corresponding side. A safety spring 611 sleeved on the magnetic flux piston 61 is connected between the two clamping seats 610 and the retaining rings 68 on the corresponding side.

[0031] Furthermore, push covers 612 are fixed on the sealing end caps 67 at both ends of the magnetic flux piston 61, and the push covers 612 are connected to the corresponding return springs 69.

[0032] Furthermore, an adjusting screw 613 is threaded onto the piston end cap 66 at the end away from the piston rod 3, and the end of the adjusting screw 613 abuts against the corresponding clamping seat 610.

[0033] The piston seat 62 is fixed relative to the piston rod 3 via the piston outer body 65, meaning their movements are consistent. Therefore, the opening degree of the valve port 6201 mainly depends on the vertical movement of the spool valve 63. Assuming the oil flows from the rod chamber to the rodless chamber, its path is as follows... Figure 6 As shown in the figure, it is easy to see that under the action of oil pressure, the spool 63 of the slide valve slides downward, creating a gap. The flow of hydraulic oil in the gap forms a damping force. The principle of fluid flowing from the rodless chamber to the rod chamber is basically the same, the difference being that the spool 63 of the slide valve moves upward.

[0034] The opening degree of valve port 6201 is adjusted through the interaction between the magnetorheological piston 61 inside the spool valve core 63 and the spool valve. The main function of the magnetorheological piston 61 is to adjust the opening pressure of the gap between the spool valve core 63 and the piston seat 62. It needs to work in conjunction with the excitation coil 64 on the piston seat 62. The working principle of the magnetorheological piston 61 is similar to that of a magnetorheological fluid damper, except that a throttling orifice 6102 is used instead of a complex valve plate and valve structure. At the same time, it is not the magnetorheological piston 61 that moves up and down, but the spool valve core 63. The movement of the spool valve core 63 causes the volumes of the upper and lower parts of the magnetorheological piston 61 to be inconsistent, forcing the magnetorheological fluid to flow between the throttling orifice 6102. When current is passed through the excitation coil 64 on the piston seat 62, a magnetic field is generated. Under the action of this magnetic field, the properties of the magnetorheological fluid inside the spool valve core 63 change. As the magnetic field gradually increases, the magnetorheological fluid will gradually transform into a semi-solid state. During the transformation, the viscous resistance of the fluid flowing through the throttling orifice 6102 will continuously increase, which will also increase the sliding resistance of the spool valve core 63. This makes it more difficult to open the valve gap and has a stronger damping effect.

[0035] To ensure that the spool valve core 63 and piston seat 62 are in a closed state when not in motion, and to allow for timely and accurate upward and downward sliding to open the valve during vertical vibration, a return spring 69 is added to the spool valve core 63. Under normal circumstances, the magnetohydrodynamic piston 61 moves as a whole with the piston rod 3, piston seat 62, and piston outer body 65; only the spool valve core 63 is in a relatively floating state. Under the action of the return spring 69, the spool valve core 63 can smoothly slide between the upward, neutral, and downward positions, changing the valve opening. To allow the oil pressure to act more effectively on the spool valve core 63, a push cap 612 is added at the sealing end cap 67 to increase the interaction area between the hydraulic oil and the spool valve core 63. Therefore, the ease of opening the valve by sliding the spool valve core 63 mainly depends on three factors: the force of the oil pressure acting on the push cap 612, the pressure and thrust difference of the return spring 69, and the damping force of the magnetohydrodynamic fluid inside the spool valve core 63. The damping force is the main resistance to valve opening.

[0036] When a strong magnetic field causes the magnetorheological fluid inside the spool valve 63 to essentially solidify and lose its fluidity, the magnetorheological piston 61 and the spool valve 63 will be fixed together by the magnetorheological fluid. If the magnetorheological piston 61 were directly fixed to the piston rod 3, the spool valve 63 would be unable to move to open the valve, directly preventing oil flow and potentially damaging components under excessive pressure. Therefore, the magnetorheological piston 61 is connected to the piston rod 3 by a safety spring 611.

[0037] Under normal circumstances, the magnetic flux piston 61 is pressed against the piston rod 3 by the pressure seat 610 and the safety spring 611. When the damping provided by the magnetic fluid is too large, the magnetic flux piston 61 can push the safety spring 611 to slide up and down in the inner hole of the pressure seat 610. In this process, the magnetic flux piston 61 and the slide valve core 63 are equivalent to a whole, sliding up and down to open the gap between the piston seat 62 and the slide valve core 63 for overflow. Under normal conditions, only the slide valve core 63 should slide. The preload of the lower pressure seat 610 on the safety spring 611 can be adjusted by adjusting the screw 613. As long as the oil pressure is greater than the preload, overflow can occur.

[0038] In summary, the oil-based magnetorheological damper of this invention can change the damping without replacing the hydraulic oil, mainly due to its internal magnetorheological slide valve piston mechanism. Compared with those magnetorheological dampers that replace hydraulic oil, it can effectively improve the shortcomings of the aforementioned traditional magnetorheological dampers. At the same time, it greatly reduces the factors that make damping adjustment uncontrollable, as only a small amount of magnetorheological fluid is inside the slide valve core, making control relatively simple. Compared to dampers where the entire cylinder is filled with magnetorheological fluid, the new damper has a smaller excitation current and a more flexible response. Components such as those on the magnetorheological slide valve piston mechanism and the seals on the end caps can be interchanged with those of traditional dampers because its damping medium is still hydraulic oil, which also results in better linear damping.

[0039] The implementation of the present invention has been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are illustrative and not intended to limit the present invention. Those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. An oil-based magnetohydrodynamic damper, comprising a cylinder, a floating separator piston, and a piston rod, wherein a bottom end cap and a top end cap are fixed to the bottom and top of the cylinder, respectively; the floating separator piston is slidably sleeved inside the cylinder; the internal space of the cylinder from the floating separator piston to the bottom end cap is a gas chamber containing gas at a certain pressure; the internal space of the cylinder from the floating separator piston to the top end cap is an oil chamber filled with hydraulic oil; characterized in that: A magnetic flow valve piston mechanism is slidably connected in the oil chamber, and the lower end of the piston rod extends from the top cover into the cylinder body and is fixedly connected to the magnetic flow valve piston mechanism. The magnetohydrodynamic slide valve piston mechanism includes a magnetohydrodynamic piston, a piston seat, a slide valve core, an excitation coil, and a piston outer body; The piston outer body is slidably connected to the inside of the cylinder body, the piston seat is fixedly connected to the inside of the piston outer body, the excitation coil is fixedly connected to the annular groove on the outer circular wall of the piston seat, and piston end caps are fixed to the two shaft ends of the piston seat respectively, and the two piston end caps have hollow holes for hydraulic oil to pass through. The spool valve core is slidably sleeved on the inner hole of the piston seat. Multiple annular plates are spaced axially on the outer circumferential wall of the spool valve core, and multiple flow holes are spaced circumferentially on each annular plate. Two annular groove-shaped valve ports are spaced axially on the inner hole of the piston seat. Multiple flow channels are spaced circumferentially on the two axial end faces of the piston seat. Each flow channel at the two axial ends is connected to the valve port on the corresponding side. When the spool valve core moves axially, it can change the opening degree of the valve port. The two ends of the slide valve core are respectively fixed with sealing end caps, and the slide valve core is filled with magnetorheological fluid. The magnetic flux piston has an annular portion in the middle, and multiple throttling holes are spaced along the circumferential direction on the outer peripheral wall of the annular portion. The magnetic flux piston is slidably sleeved with the sealing end caps at both ends of the slide valve core, and the annular portion of the magnetic flux piston is located inside the slide valve core. A retaining ring is fixed on each end of the magnetic flux piston, and a return spring sleeved on the magnetic flux piston is connected between the retaining rings at both ends and the sealing end caps on the corresponding sides. A clamping seat is slidably sleeved on each end of the magnetic flux piston. The clamping seat at one end is sleeved on the piston rod end, and the clamping seat at the other end is sleeved in the piston end cap on the corresponding side. A safety spring sleeved on the magnetic flux piston is connected between the two clamping seats and the retaining rings on the corresponding sides.

2. The oil magnetohydrodynamic damper according to claim 1, characterized in that: The outer ring of the piston body is provided with a combined sealing ring, which is used for dynamic sealing as the piston body slides along the inside of the cylinder.

3. The oil magnetohydrodynamic damper according to claim 1, characterized in that: The sealing end cap is provided with a Glyd ring that fits onto the magnetohydrodynamic piston.

4. The oil magnetohydrodynamic damper according to claim 1, characterized in that: Push covers are fixed to the sealing end caps at both ends of the magnetorheological piston, and the push covers are abutted against the corresponding reset springs.

5. The oil magnetohydrodynamic damper according to claim 1, characterized in that: An adjusting screw is threaded onto the piston end cap at the end furthest from the piston rod, and the end of the adjusting screw rests against the corresponding clamping seat.

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