Magnetorheological damper for reducing piston rod ejection force of magnetorheological damper

Abstract

This invention discloses a magnetorheological damper for reducing the piston rod push-out force, relating to the field of magnetorheological damping technology. It includes an outer cylinder and an oil reservoir coaxially sleeved inside the outer cylinder, forming an annular flow channel between the outer cylinder and the oil reservoir. Inside the oil reservoir, from top to bottom, are arranged an upper guide assembly, a piston rod assembly, a shut-off valve assembly, and a floating piston assembly. This invention solves the problem of excessive piston rod push-out force in traditional single-cylinder magnetorheological dampers by placing a shut-off valve assembly in the lower section of the oil reservoir, thus dividing the single working chamber of the traditional single-cylinder magnetorheological damper into three independent chambers: an upper chamber, a lower chamber, and a lower-lower chamber. During compression and extension strokes, the maximum damping force is mainly borne by the shut-off valve assembly, rather than directly acting on the floating piston. This allows the floating piston assembly to only compensate for piston rod volume changes without providing high-pressure support.

Description

Technical Field

[0001] This invention relates to the field of magnetorheological vibration reduction technology, and specifically to a magnetorheological vibration damper that reduces the piston rod top force of the magnetorheological vibration damper. Background Technology

[0002] Magnetorheological dampers are a new type of intelligent variable damping damper widely used in the suspension systems of high-end sports vehicles. Their working principle utilizes the rapid viscosity change of magnetorheological fluid under the influence of a magnetic field. By adjusting the current, the damping force is altered, offering advantages such as a wide range of damping force variation, fast response speed, and the absence of the reverse action phenomenon found in valve-type dampers. Compared to traditional valve-type variable damping dampers such as CDC and DCC, magnetorheological dampers achieve more precise real-time damping control, significantly improving vehicle handling stability and driving safety.

[0003] However, traditional monotube magnetorheological dampers employ a monotube structure, such as... Figure 10 As shown, an internal floating piston separates the working chamber from the air chamber, which is filled with high-pressure nitrogen gas at 3-3.5 MPa. This serves two purposes: firstly, to compensate for volume changes during piston rod insertion and removal, and secondly, to provide support for maximum compressive damping force. This structure results in the shock absorber piston rod experiencing an outward force of up to 900-1300 N, which is directly transmitted to the top mount supporting the shock absorber, causing it to be over-pre-compressed and lose its elasticity. In the specific application scenarios of high-end luxury cars where an extremely smooth road feel is desired, this rough sound and vibration transmission characteristic severely affects the vehicle's NVH performance and ride comfort. Summary of the Invention

[0004] This invention provides a magnetorheological damper that reduces the piston rod top force of a magnetorheological damper, thereby solving the problems mentioned in the background art.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A magnetorheological damper for reducing piston rod output force includes an outer cylinder and an oil reservoir coaxially sleeved inside the outer cylinder. An annular flow channel is formed between the outer cylinder and the oil reservoir. Inside the oil reservoir, from top to bottom, are arranged an upper guide assembly, a piston rod assembly, a shut-off valve assembly, and a floating piston assembly. A base is connected to the bottom of the oil reservoir. An air chamber is formed between the floating piston assembly and the base. An air inlet communicating with the air chamber is provided on the oil reservoir. The shut-off valve assembly is fixed in the lower section of the oil reservoir, dividing the interior of the oil reservoir into three independent magnetorheological fluid chambers that can be switched on and off by the shut-off valve assembly: an upper chamber between the upper guide assembly and the piston rod assembly, a lower chamber between the piston rod assembly and the shut-off valve assembly, and a lower-lower chamber between the shut-off valve assembly and the floating piston assembly. The air pressure of the air chambers is MPa.

[0006] A further improvement of the technical solution of the present invention is that: the piston rod assembly includes a piston rod, a coil core fixed to the end of the piston rod, and a guide ring. The outer wall of the guide ring slides in conjunction with the inner wall of the oil reservoir, and a mm gap is left between the guide ring and the inner wall of the oil reservoir. Multiple magnetorheological fluid flow holes are opened on the guide ring, and a coil is wound around the outer side of the coil core.

[0007] A further improvement of the technical solution of the present invention is that: the shut-off valve assembly includes a valve body, a first baffle and a second baffle symmetrically arranged on both sides of the valve body, a cylindrical pin connecting the first baffle and the second baffle, a spring sheet for elastically abutting the first baffle and the second baffle, and a positioning pin and a cover plate for fixing the valve body; the valve body is provided with a flow hole during compression, a compensation hole during recovery, a recovery compression flow hole and a blind hole, the positioning pin is press-fitted into the blind hole and welded to the oil reservoir, and the spring sheet is pressed onto the valve body by the cover plate, so that the first baffle and the second baffle are elastically fitted to the valve body.

[0008] A further improvement of the technical solution of the present invention is that: the upper end of the oil storage tank is provided with a flow hole communicating with the upper cavity, and the lower end is provided with a through hole communicating with the lower cavity; the side of the valve body is provided with a magnetorheological fluid flow hole aligned with the through hole at the lower end of the oil storage tank; the annular flow channel is connected to the upper cavity through the flow hole at the upper end of the oil storage tank, and is connected to the lower cavity through the magnetorheological fluid flow hole on the side of the valve body.

[0009] A further improvement of the technical solution of the present invention is that: a positioning ring is welded on the oil storage tank, the outer cylinder is welded to the outside of the oil storage tank and the positioning ring, a lifting ring is welded on the base, a screw cap is connected to the upper end of the upper guide assembly, and an oil seal, a dust seal and an O-ring are provided inside the upper guide assembly.

[0010] A further improvement of the technical solution of the present invention is that: the blocking valve assembly is an integrated valve body structure, the integrated valve body is directly welded or fixed to the lower section of the oil reservoir, and the integrated valve body is provided with a magnetorheological fluid flow channel adapted to the stretching and compression stroke.

[0011] A further improvement of the technical solution of the present invention is that: the floating piston assembly is slidably sealed with the inner wall of the oil reservoir, and the lower cavity is a magnetorheological fluid variation compensation space, which is used to compensate for the volume change inside the oil reservoir when the piston rod extends and retracts.

[0012] A further improvement of the technical solution of the present invention is that: the oil storage tank is filled with magnetorheological fluid, which fills the upper cavity, lower cavity, lower lower cavity and the annular flow channel, and the magnetorheological fluid is isolated from the gas chamber by a floating piston assembly.

[0013] A further improvement of the technical solution of the present invention is that: the floating piston assembly is slidably sealed with the inner wall of the oil reservoir, and the lower cavity is a magnetorheological fluid variation compensation space, which is used to compensate for the volume change inside the oil reservoir when the piston rod extends and retracts.

[0014] A further improvement of the technical solution of the present invention is that: the upper guide assembly is sealed to the inner wall of the oil reservoir, and the upper guide assembly and the piston rod are slidably sealed to prevent leakage of magnetorheological fluid inside the oil reservoir.

[0015] Due to the adoption of the above technical solution, the technical progress achieved by this invention compared to the prior art is as follows: This invention provides a magnetorheological damper that reduces the piston rod push-out force. By installing a shut-off valve assembly in the lower section of the oil reservoir, the single working chamber of the traditional monotube magnetorheological damper is divided into three independent chambers: an upper chamber, a lower chamber, and a lower-lower chamber. This solves the problem of excessive piston rod push-out force in traditional structures. During the compression and extension strokes, the maximum damping force is mainly borne by the shut-off valve assembly, rather than acting directly on the floating piston. This allows the floating piston assembly to only compensate for changes in piston rod volume without providing high-pressure support. Based on this, the air chamber filling pressure can be significantly reduced from the traditional 3-3.5 MPa to about 1 MPa, and the piston rod push-out force is correspondingly reduced from 900-1300 N to the level of ordinary dampers. This effectively prevents the upper support top rubber from being over-pre-compressed and losing its elastic activity, retaining the necessary buffering function of the top rubber, and significantly improving the vehicle's noise, vibration, and harshness (NVH) performance. Meanwhile, the shut-off valve assembly, through the precise coordination of the valve body, baffle, and spring plate, achieves automatic switching and on / off control of the magnetorheological fluid flow channel during the stretching and compression strokes. During compression, baffle two closes, and the magnetorheological fluid flows into the lower chamber through the compression flow hole; during stretching, baffle one closes, and the magnetorheological fluid replenishes the lower chamber in a timely manner through the recovery compensation hole. This ensures that the magnetorheological fluid around the coil core is always in a full state, avoiding the "dry popping" phenomenon caused by untimely fluid supply and guaranteeing the stable operation of the vibration damper under various working conditions. In addition, the annular flow channel formed by the double-cylinder structure effectively disperses the fluid pressure, enabling the vibration damper to combine the advantages of hydraulic damping and magnetorheological control. It retains the excellent characteristics of magnetorheological vibration dampers, such as a large range of damping force and fast response speed, while achieving a smooth road feel comparable to ordinary vibration dampers. This invention successfully breaks through the long-standing technical bottleneck that makes it difficult to apply magnetorheological dampers to high-end luxury cars, allowing its application scope to be easily expanded to luxury models with extreme requirements for NVH performance, and providing key technical support for the popularization of active suspension systems. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the vertical cross-sectional structure of the present invention; Figure 2 This is a schematic diagram of the transverse cross-sectional structure of the present invention; Figure 3 This is a schematic diagram of the blocking valve assembly structure of the present invention; Figure 4 This is an exploded view of the blocking valve assembly of the present invention; Figure 5 For the present invention Figure 1 Enlarged structural diagram at point A in the middle; Figure 6 For the present invention Figure 2 Enlarged structural diagram at point B; Figure 7 For the present invention Figure 2 Enlarged structural diagram at point C; Figure 8 This is a schematic cross-sectional view of the valve body of the present invention; Figure 9 This is a schematic diagram of the main structure of the present invention; Figure 10 This is a cross-sectional structural diagram of the prior art of the present invention.

[0017] In the diagram: 1. Outer cylinder; 2. Annular flow channel; 3. Oil reservoir; 4. Upper guide assembly; 5. Piston rod assembly; 6. Floating piston assembly; 7. Air inlet; 9. Shut-off valve assembly; 11. Guide ring; 12. Coil core; 13. Baffle 1; 14. Baffle 2; 15. Spring plate; 16. Cover plate; 17. Positioning pin; 18. Valve body; 19. Flow hole during compression; 20. Compensation hole during recovery; 21. Flow hole for recovery and compression; 22. Blind hole; 23. Magnetorheological fluid flow hole; 25. Upper chamber; 26. Lower chamber; 27. Lower-lower chamber; 28. Piston rod; 29. ​​Coil; 30. Screw cap; 31. Base; 32. Lifting ring; 33. Air chamber; 34. Cylindrical pin. Detailed Implementation

[0018] The present invention will be further described in detail below with reference to embodiments: Example 1, as Figures 1-10As shown, the present invention provides a magnetorheological damper for reducing the piston rod top force of a magnetorheological damper, including an outer cylinder 1 and an oil reservoir 3 coaxially sleeved inside the outer cylinder 1. An annular flow channel 2 is formed between the outer cylinder 1 and the oil reservoir 3. The oil reservoir 3 is provided with an upper guide assembly 4, a piston rod assembly 5, a shut-off valve assembly 9 and a floating piston assembly 6 arranged sequentially from top to bottom. A base 31 is connected to the bottom of the oil reservoir 3. An air chamber 33 is formed between the floating piston assembly 6 and the base 31. An air inlet 7 communicating with the air chamber 33 is provided on the oil reservoir 3. The shut-off valve assembly 9 is fixed in the lower section of the oil reservoir 3, dividing the interior of the oil reservoir 3 into three independent magnetorheological fluid chambers that can be opened and closed by the shut-off valve assembly 9. These are the upper chamber 25 between the upper guide assembly 4 and the piston rod assembly 5, the lower chamber 26 between the piston rod assembly 5 and the shut-off valve assembly 9, and the lower-lower chamber 27 between the shut-off valve assembly 9 and the floating piston assembly 6. The air pressure of the air chamber 33 is 1 MPa.

[0019] It should be noted that: the annular flow channel 2 between the outer cylinder 1 and the oil reservoir 3 provides a circulating flow channel for the magnetorheological fluid, effectively dispersing the liquid pressure; the upper guide assembly 4 is used to guide the axial movement of the piston rod assembly 5 and prevent the magnetorheological fluid from leaking; the piston rod assembly 5 is the core moving part of the shock absorber, reciprocating during tension and compression; the shut-off valve assembly 9 is fixed in the lower section of the oil reservoir 3, dividing the interior of the oil reservoir 3 into three independent chambers, and controlling the flow of the magnetorheological fluid between each chamber through its internal structure; the floating piston assembly 6 isolates the magnetorheological fluid from the gas chamber 33, while compensating for the volume change caused by the movement of the piston rod assembly 5; the gas chamber 33 is filled with 1MPa low-pressure gas, which significantly reduces the piston rod top force compared to the traditional 3-3.5MPa high-pressure gas.

[0020] In this embodiment, by setting a shut-off valve assembly 9 in the lower section of the oil reservoir 3, the single working chamber of the traditional monotube magnetorheological damper is divided into three independent chambers. This allows the maximum damping force to be mainly borne by the shut-off valve assembly 9, while the floating piston assembly 6 only needs to compensate for changes in piston rod volume, without needing to provide high-pressure support. Based on this, the inflation pressure of the air chamber 33 can be reduced to 1 MPa, and the piston rod top force is correspondingly reduced to the level of a conventional damper. This effectively prevents the upper support top rubber from being over-pre-compressed and losing its elasticity, significantly improving the vehicle's NVH performance and enabling the magnetorheological damper to meet the stringent requirements of high-end luxury cars for a smooth road feel.

[0021] Example 2, as Figures 1-10As shown, based on Embodiment 1, the present invention provides a technical solution: Preferably, the piston rod assembly 5 includes a piston rod 28, a coil core 12 fixed to the end of the piston rod 28, and a guide ring 11. The outer wall of the guide ring 11 slides in fit with the inner wall of the oil reservoir 3, and a 1mm gap is left between the guide ring 11 and the inner wall of the oil reservoir 3. Multiple magnetorheological fluid flow holes are opened on the guide ring 11. A coil 29 is wound around the outer side of the coil core 12. The shut-off valve assembly 9 includes a valve body 18, a first baffle 13 and a second baffle 14 symmetrically arranged on both sides of the valve body 18, a cylindrical pin 34 connecting the first baffle 13 and the second baffle 14, a spring sheet 15 for elastically abutting the first baffle 13 and the second baffle 14, and a fixing pin for fixing the valve body 18. Positioning pin 17 and cover plate 16; valve body 18 is provided with compression flow hole 19, recovery compensation hole 20, recovery compression flow hole 21 and blind hole 22. Positioning pin 17 is pressed into blind hole 22 and welded to oil reservoir 3. Spring plate 15 is pressed onto valve body 18 through cover plate 16, so that baffle 13 and baffle 24 are elastically fitted to valve body 18. Oil reservoir 3 is provided with flow hole at upper end communicating with upper cavity 25 and through hole at lower end communicating with lower cavity 27. Magnetorheological fluid flow hole 23 is provided on the side of valve body 18 aligned with through hole at lower end of oil reservoir 3. Annular flow channel 2 is connected to upper cavity 25 through flow hole at upper end of oil reservoir 3 and to lower cavity 27 through magnetorheological fluid flow hole 23 on side of valve body 18.

[0022] It should be noted that the 1mm gap between the guide ring 11 and the inner wall of the oil reservoir 3 is the working gap for the magnetorheological fluid to flow through the coil core 12. The magnetic field generated by the coil 29 after it is energized acts on the magnetorheological fluid in this gap, and the damping force is adjusted by changing the fluidity of the magnetorheological fluid. The multiple magnetorheological fluid flow holes on the guide ring 11 ensure that the liquid flows freely on both sides of the gap. The compression flow hole 19, the recovery compensation hole 20, and the recovery compression flow hole 21 on the valve body 18 correspond to the liquid flow channels of different strokes. The baffle 13 and the baffle 24 fit against the valve body 18 under the elastic action of the spring plate 15, and automatically open or close the corresponding flow channels according to the direction of liquid pressure, so as to realize the flow channel switching of the stretching and compression strokes.

[0023] In this embodiment, the precise structural design of the blocking valve assembly 9 enables automatic switching and on / off control of the magnetorheological fluid flow channel during the stretching and compression strokes. During the compression stroke, the pressure in the lower chamber 26 increases, and the magnetorheological fluid pushes the second baffle 14 to close the recovery compensation hole 20. At the same time, the first baffle 13 remains closed. The liquid flows into the valve body 18 through the compression flow hole 19, and then flows into the annular flow channel 2 through the recovery compression flow hole 21 and the magnetorheological fluid flow hole 23. Finally, it returns to the upper chamber 25 through the upper flow hole of the oil reservoir 3, forming a complete cycle. During the stretching stroke, the pressure in the upper chamber 25 increases, and the liquid enters the annular flow channel 2 through the upper flow hole of the oil reservoir 3. It enters the valve body 18 through the magnetorheological fluid flow hole 23 on the side of the valve body 18, pushing the first baffle 13 to open the recovery compensation hole 20. At the same time, the second baffle 14 remains closed. The liquid flows into the lower chamber 26 through the recovery compensation hole 20, timely compensating for the volume loss caused by the withdrawal of the piston rod 28. This design ensures that the magnetorheological fluid around the coil core 12 is always fully supplied, avoiding the "dry popping" phenomenon caused by untimely fluid supply and ensuring the stable operation of the vibration damper under various working conditions.

[0024] Example 3, as Figures 1-10 As shown, based on Embodiment 1, the present invention provides a technical solution: Preferably, a positioning ring is welded to the oil reservoir 3, the outer cylinder 1 is welded to the outside of the oil reservoir 3 and the positioning ring, a lifting ring 32 is welded to the base 31, a screw cap 30 is connected to the upper end of the upper guide assembly 4, an oil seal, a dust seal and an O-ring are provided inside the upper guide assembly 4, the shut-off valve assembly 9 is an integral valve body structure, the integral valve body is directly welded or fixed to the lower section of the oil reservoir 3, and the integral valve body is provided with a magnetorheological fluid flow channel adapted to the stretching and compression strokes, the floating piston assembly 6 is slidably sealed with the inner wall of the oil reservoir 3, and the lower cavity 27 is a magnetorheological fluid variation compensation space. The oil reservoir 3 is filled with magnetorheological fluid to compensate for the volume change inside the oil reservoir 3 when the piston rod 28 extends and retracts. The magnetorheological fluid is filled in the upper cavity 25, lower cavity 26, lower lower cavity 27 and the annular flow channel 2. The magnetorheological fluid is isolated from the gas chamber 33 by the floating piston assembly 6. The floating piston assembly 6 is slidably sealed to the inner wall of the oil reservoir 3. The lower lower cavity 27 is a magnetorheological fluid displacement compensation space to compensate for the volume change inside the oil reservoir 3 when the piston rod 28 extends and retracts. The upper guide assembly 4 is sealed to the inner wall of the oil reservoir 3 and is slidably sealed to the piston rod 28 to prevent the magnetorheological fluid inside the oil reservoir 3 from leaking.

[0025] It should be noted that: the positioning ring is used to ensure the coaxiality between the outer cylinder 1 and the oil reservoir 3, and to ensure the uniformity of the annular flow channel 2; the lifting ring 32 is used to connect the shock absorber to the frame and axle; the screw cap 30 is used to fix the upper guide assembly 4 and adjust the preload; the oil seal, dust seal and O-ring constitute a multi-seal system to prevent magnetorheological fluid leakage and external impurities from entering; the integrated valve body structure simplifies the manufacturing and assembly process of the shut-off valve assembly 9 and improves the structural reliability and sealing performance; the sliding sealing fit of the floating piston assembly 6 ensures the complete isolation between the gas chamber 33 and the magnetorheological fluid chamber; the lower chamber 27 serves as a magnetorheological fluid variation compensation space, which automatically compensates for volume changes by moving the floating piston assembly 6 when the piston rod 28 extends and retracts.

[0026] In this embodiment, multiple sealing structures and precision assembly processes ensure the sealing reliability and performance stability of the shock absorber during long-term use. The welded structure of the positioning ring and outer cylinder 1 ensures the uniformity of the annular flow channel 2, allowing the magnetorheological fluid to flow smoothly and the pressure distribution to be uniform. The integrated valve body structure reduces the number of parts, lowers the assembly difficulty and leakage risk. The combined design of oil seals, dust seals and O-rings effectively prevents magnetorheological fluid leakage and external impurities from entering, extending the service life of the shock absorber. The precise fit between the floating piston assembly 6 and the oil reservoir 3 ensures the reliable operation of the lower chamber 27 as a variable compensation space, enabling the shock absorber to maintain stable performance under various working conditions. The annular flow channel 2 formed by the double-cylinder structure effectively disperses the liquid pressure, giving the shock absorber the advantages of both hydraulic damping and magnetorheological control. It retains the excellent characteristics of magnetorheological shock absorbers, such as a large range of damping force and fast response speed, while achieving a smooth road feel comparable to ordinary shock absorbers.

[0027] The working principle of this magnetorheological vibration damper, which reduces the piston rod output force of the magnetorheological vibration damper, will be explained in detail below.

[0028] like Figures 1-10As shown, when the magnetorheological damper is working, the piston rod assembly 5 reciprocates relative to the oil reservoir 3 under external excitation. Low-pressure gas of 1 MPa is injected into the gas chamber 33 through the air inlet 7 to provide appropriate back pressure for the floating piston assembly 6, enabling it to reliably drive the magnetorheological fluid and compensate for volume changes, while ensuring the piston rod output force remains low. During the compression stroke, the piston rod assembly 5 moves downwards, the lower chamber 26 decreases in volume and increases in pressure, becoming a high-pressure zone; the upper chamber 25 increases in volume and decreases in pressure, becoming a low-pressure zone; the lower chamber 27 increases in volume and decreases in pressure, becoming a low-pressure zone. The high-pressure magnetorheological fluid in the lower chamber 26 flows upwards through the 1 mm gap between the guide ring 11 and the inner wall of the oil reservoir 3, entering the upper chamber 25. Simultaneously, due to the increased pressure in the lower chamber 26, the baffle 14 in the shut-off valve assembly 9 is tightly fitted to the valve body 18 under liquid pressure, closing the compensation hole 20 during the recovery phase; the baffle 13 also remains closed. Excess magnetorheological fluid in the lower chamber 26 enters the valve body 18 through the compression flow hole 19, then flows into the annular flow channel 2 through the restoration compression flow hole 21 and the magnetorheological fluid flow hole 23 on the side of the valve body 18, and returns to the upper chamber 25 through the flow hole at the upper end of the oil reservoir 3, forming a complete cycle. The excess volume caused by the piston rod 28 being squeezed in is compensated by the rightward movement of the floating piston assembly 6, and the volume of the lower chamber 27 increases accordingly. During the stretching stroke, the piston rod assembly 5 moves upward, the volume of the upper chamber 25 decreases and the pressure increases, becoming a high-pressure zone; the volume of the lower chamber 26 increases and the pressure decreases, becoming a low-pressure zone; the volume of the lower chamber 27 decreases and the pressure increases, becoming a high-pressure zone. The high-pressure magnetorheological fluid in the upper chamber 25 flows downward through the 1mm gap between the guide ring 11 and the inner wall of the oil reservoir 3, and enters the lower chamber 26. Simultaneously, due to the increased pressure in the lower chamber 27, the baffle 13 in the blocking valve assembly 9 is pushed open by the liquid pressure, opening the compensation hole 20 during restoration; the baffle 24 remains closed. The high-pressure magnetorheological fluid in the lower chamber 27 enters the magnetorheological fluid flow hole 23 on the side of the valve body 18 through the through hole at the lower end of the oil reservoir 3, and flows into the lower chamber 26 through the internal flow channel of the valve body 18 and the compensation hole 20 during restoration, timely compensating for the volume loss caused by the withdrawal of the piston rod 28. The volume reduction caused by the withdrawal of the piston rod 28 is compensated by the leftward movement of the floating piston assembly 6, and the volume of the lower chamber 27 decreases accordingly. Throughout the operation, the coil 29 is supplied with current of different magnitudes according to the control command, generating a magnetic field of corresponding intensity around the coil core 12. The direction of the magnetic field is perpendicular to the flow direction of the magnetorheological fluid and acts on the 1mm gap between the guide ring 11 and the inner wall of the oil reservoir 3. Under the action of the magnetic field, the yield stress of the magnetorheological fluid changes, and the flow resistance when flowing through the gap changes accordingly, thus generating different damping forces. By adjusting the current in real time, the damping force can be continuously adjusted to meet the requirements of vibration reduction performance under different driving conditions and road conditions.

[0029] The present invention has been described in detail above. However, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, any modifications or improvements that do not depart from the spirit of the present invention are within the scope of protection of the present invention.

Claims

1. A magnetorheological damper for reducing the piston rod push-out force of a magnetorheological damper, characterized in that: The system includes an outer cylinder (1) and an oil reservoir (3) coaxially sleeved inside the outer cylinder (1). An annular flow channel (2) is formed between the outer cylinder (1) and the oil reservoir (3). The oil reservoir (3) is provided with an upper guide assembly (4), a piston rod assembly (5), a shut-off valve assembly (9), and a floating piston assembly (6) arranged sequentially from top to bottom. A base (31) is connected to the bottom of the oil reservoir (3). An air chamber (33) is formed between the floating piston assembly (6) and the base (31). The oil reservoir (3) has openings in the air chamber (33). The air inlet (7) is connected; the shut-off valve assembly (9) is fixed in the lower section of the oil reservoir (3), dividing the interior of the oil reservoir (3) into three independent magnetorheological fluid chambers that can be switched on and off by the shut-off valve assembly (9), namely the upper chamber (25) between the upper guide assembly (4) and the piston rod assembly (5), the lower chamber (26) between the piston rod assembly (5) and the shut-off valve assembly (9), and the lower chamber (27) between the shut-off valve assembly (9) and the floating piston assembly (6). The air pressure of the air chamber (33) is 1 MPa.

2. A magnetorheological damper for reducing the piston rod push-out force according to claim 1, characterized in that: The piston rod assembly (5) includes a piston rod (28), a coil core (12) fixed to the end of the piston rod (28), and a guide ring (11). The outer wall of the guide ring (11) slides in fit with the inner wall of the oil reservoir (3), and there is a 1mm gap between the guide ring (11) and the inner wall of the oil reservoir (3). Multiple magnetorheological fluid flow holes are provided on the guide ring (11), and a coil (29) is wound around the outer side of the coil core (12).

3. A magnetorheological damper for reducing the piston rod push-out force according to claim 1, characterized in that: The shut-off valve assembly (9) includes a valve body (18), a first baffle (13) and a second baffle (14) symmetrically arranged on both sides of the valve body (18), a cylindrical pin (34) connecting the first baffle (13) and the second baffle (14), a spring plate (15) for elastically abutting the first baffle (13) and the second baffle (14), and a positioning pin (17) and a cover plate (16) for fixing the valve body (18). The valve body (18) is provided with a flow hole (19) for compression, a compensation hole (20) for recovery, a recovery compression flow hole (21) and a blind hole (22). The positioning pin (17) is press-fitted into the blind hole (22) and welded to the oil reservoir (3). The spring plate (15) is pressed onto the valve body (18) through the cover plate (16) so that the first baffle (13) and the second baffle (14) are elastically fitted to the valve body (18).

4. A magnetorheological damper for reducing the piston rod push-out force of a magnetorheological damper according to claim 3, characterized in that: The oil storage tank (3) has a flow hole at the upper end that communicates with the upper cavity (25) and a through hole at the lower end that communicates with the lower cavity (27). The valve body (18) has a magnetorheological fluid flow hole (23) on its side that is aligned with the through hole at the lower end of the oil storage tank (3). The annular flow channel (2) communicates with the upper cavity (25) through the flow hole at the upper end of the oil storage tank (3) and with the lower cavity (27) through the magnetorheological fluid flow hole (23) on the side of the valve body (18).

5. A magnetorheological damper for reducing the piston rod push-out force according to claim 1, characterized in that: A positioning ring is welded on the oil storage cylinder (3), the outer cylinder (1) is welded to the outside of the oil storage cylinder (3) and the positioning ring, a lifting ring (32) is welded on the base (31), a screw cap (30) is connected to the upper end of the upper guide assembly (4), and an oil seal, a dust seal and an O-ring are provided inside the upper guide assembly (4).

6. A magnetorheological damper for reducing the piston rod push-out force according to claim 1, characterized in that: The shut-off valve assembly (9) is an integrated valve body structure. The integrated valve body is directly welded or fixed to the lower section of the oil reservoir (3), and the integrated valve body is provided with a magnetorheological fluid flow channel adapted to the stretching and compression stroke.

7. A magnetorheological damper for reducing the piston rod push-out force of a magnetorheological damper according to claim 1, characterized in that: The floating piston assembly (6) is slidably sealed to the inner wall of the oil reservoir (3). The lower chamber (27) is a magnetorheological fluid variation compensation space, used to compensate for the volume change inside the oil reservoir (3) when the piston rod (28) extends and retracts.

8. A magnetorheological damper for reducing the piston rod ejection force according to claim 1, characterized in that: The oil storage tank (3) is filled with magnetorheological fluid, which fills the upper cavity (25), lower cavity (26), lower lower cavity (27) and annular flow channel (2), and the magnetorheological fluid is isolated from the gas chamber (33) by the floating piston assembly (6).

9. A magnetorheological damper for reducing the piston rod ejection force according to claim 1, characterized in that: The floating piston assembly (6) is slidably sealed to the inner wall of the oil reservoir (3). The lower chamber (27) is a magnetorheological fluid variation compensation space, used to compensate for the volume change inside the oil reservoir (3) when the piston rod (28) extends and retracts.

10. A magnetorheological damper for reducing the piston rod ejection force according to claim 1, characterized in that: The upper guide assembly (4) is sealed to the inner wall of the oil reservoir (3), and the upper guide assembly (4) and the piston rod (28) are slidably sealed to prevent the leakage of magnetorheological fluid inside the oil reservoir (3).

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