Magneto-rheological shock absorber

Abstract

The invention provides a magnetorheological damper which comprises a first cylinder body, a first piston, a first connecting rod and a permanent magnet, the first piston is fixed to the first connecting rod, the first cylinder body is provided with a first cavity, the first cavity is provided with magnetorheological fluid, and the magnetorheological fluid flows through a first channel when the first piston moves in the first cavity; the permanent magnet is arranged close to the first channel and at least provided with a first position and a second position, and the first position is closer to the first channel relative to the second position, so that the damping force of the shock absorber when the permanent magnet is located at the first position is larger than that of the shock absorber when the permanent magnet is located at the second position. When the permanent magnet is located at the first position, the permanent magnet is closer to the first channel, the magnetic field intensity generated near the first channel is high, the magnetorheological fluid generates larger damping force under the action of a large magnetic field, and when the permanent magnet is located at the second position, the damping force of the magnetorheological fluid is small under the action of a small magnetic field.

Description

Technical Field

[0001] The present application relates to the field of vibration dampers and electromagnetic technology, and in particular to a magnetorheological vibration damper. Background Art

[0002] When a car is driving, due to the unevenness of the road surface, the vertical reaction force, longitudinal reaction force and lateral reaction force acting on the wheels fluctuate and are transmitted to the body through the suspension, thus generating vibration and impact. When these vibrations and impacts are transmitted to the frame and body, they may cause early damage to the car parts. When they are transmitted to the passengers and cargo, the passengers will feel extremely uncomfortable and the cargo may also be damaged, which will seriously affect the ride comfort and handling stability of the vehicle and the fatigue life of the vehicle parts. In order to alleviate the impact, elastic elements are installed in the car suspension, but the elastic system generates vibration during impact. Continuous vibration can easily make the passengers feel uncomfortable and tired, so dampers are installed in the car suspension.

[0003] Traditional passive suspension cannot adapt to complex road excitation and changing driving conditions. Therefore, it is imperative to develop an intelligent suspension system that can adjust its characteristics in real time according to changes in road conditions and vehicle operating conditions, which can not only ensure the vehicle's handling stability, but also make the vehicle's ride comfort reach the best state. In recent years, semi-active control suspension systems can greatly improve the vehicle's ride comfort and handling stability, and are very suitable for the characteristics of vehicle suspension systems, which has led to a significant development in its research.

[0004] As the actuator of the semi-active control suspension, the magnetorheological shock absorber uses magnetorheological fluid as the medium. By controlling the input current, the strength of the applied magnetic field can be changed, and the rheological properties of the magnetorheological fluid can be changed in milliseconds, realizing the transition between fluid and semi-solid, thereby providing controllable damping force. It has the advantages of simple structure, easy control, rapid response, low power consumption and large output force.

[0005] When driving on city roads, unless under special circumstances, the road surface is relatively flat, so a harder suspension is needed, which has better handling, better braking distance and steering performance. The greater the magnetic field strength, the greater the damping force, but the more electric energy is consumed. However, for the current domestic road conditions, there are far more flat roads than bumpy roads, so a larger magnetic field is needed most of the time in daily driving to ensure a greater damping force.

[0006] The Chinese patent authorization announcement number "CN106678256B" and the patent name "A magnetoelectric self-powered suspension shock absorber for electric vehicles" discloses a magnetorheological shock absorber structure. Although permanent magnets are set up, it mainly considers energy recovery rather than adjustment of damping force.

[0007] The Chinese patent authorization announcement number "CN221278333U" and the patent name "New Magnetorheological Automobile Shock Absorber" discloses a magnetorheological shock absorber, in which the permanent magnet 13 is fixed in the piston cylinder 1. When the piston 11 descends, the telescopic sleeve 14 is driven to fold downward through the connecting rod 12. After the telescopic sleeve 14 is folded downward, the magnetic field and magnetic force of the internal permanent magnet 13 are slowly exposed. As the permanent magnet 13 is exposed more, the strength of the magnetic field is strengthened. It can be seen that its damping force is the same as that of a spring. The greater the compression, the greater the damping force, which is consistent with the actual need for regulating the magnetorheological shock absorber. The design of the shock absorber is completely different, especially on flat roads. In order to have better braking and steering performance, the shock absorber needs to have a large damping force at any position to avoid braking nodding and serious vehicle tilting when turning. The technical solution of this patent has the same function as that of an ordinary spring, that is, the greater the compression, the greater the damping force, so the recovery stroke becomes slower at the position with greater compression, that is, when the vehicle is driving on a bumpy road, the shock absorber will shorten and harden, which greatly reduces the comfort. In theory, the shock absorber has better elasticity and higher comfort on bumpy roads, so the comfort of this design is poor. If a larger damping force is required at the initial position, it needs to be achieved by an electromagnet, which has the same performance as an ordinary magnetorheological shock absorber. Summary of the invention

[0008] The present application provides a magnetorheological damper to at least solve the technical problem of low-energy-consumption damping force adjustment existing in the prior art.

[0009] According to the present application, a magnetorheological shock absorber is provided, including a first cylinder body, a first piston, a first connecting rod and a permanent magnet. The first piston is fixed on the first connecting rod. The first cylinder body is provided with a first chamber. The first chamber is provided with a magnetorheological fluid. When the first piston moves in the first chamber, the magnetorheological fluid flows through a first channel. The permanent magnet is arranged close to the first channel. The permanent magnet is provided with at least a first position and a second position. The permanent magnet is closer to the first channel when it is in the first position than when it is in the second position, so that the damping force of the shock absorber when the permanent magnet is in the first position is greater than the damping force of the shock absorber when the permanent magnet is in the second position.

[0010] Compared with the prior art, the magnetorheological damper of the present application has the following beneficial effects: When the permanent magnet is in the first position, the permanent magnet is closer to the first channel, and the magnetic field intensity generated near the first channel is higher. The magnetorheological fluid generates a larger damping force under the larger magnetic field. The shock absorber is used on the car, which can make the suspension harder and the car handling better. Since the permanent magnet does not need to be powered, it is more energy-efficient than electromagnetic coil control. When the permanent magnet is in the second position, the permanent magnet is farther away from the first channel, and the magnetic field intensity generated near the first channel is smaller. The magnetorheological fluid has a smaller damping force under the smaller magnetic field. The shock absorber is used on the car, which can make the suspension softer and the car more comfortable. The moving permanent magnet can be achieved by conventional methods such as a reduction motor, a cylinder, a hydraulic cylinder or an electromagnet, or by designing a more ingenious structure to make the structure simpler and energy-saving and environmentally friendly. The shock absorber can also be used as a damper on other mechanical structures.

[0011] In one embodiment, the first chamber is divided into a main chamber and a sub-chamber by a control section. The first channel is located in the control section so that the main chamber and the sub-chamber are connected through the first channel. The control section is located at the first piston or at the upper or lower end of the first cylinder body. Such a design structure is more compact.

[0012] In one embodiment, the first channel includes a spiral section, an upper vertical section and a lower vertical section. The upper vertical section and the lower vertical section are arranged axially, and the spiral section is extended along the axial spiral. The upper vertical section and the lower vertical section are located at both ends of the spiral section. If the electromagnetic coil is arranged around the central axis of the piston, the magnetic flux lines are in the horizontal direction at the upper vertical section and the lower vertical section, and in the vertical direction at the spiral section. In this way, the magnetic flux lines can be perpendicular to the flow direction of the magnetorheological fluid, so that the damping effect is better.

[0013] In one embodiment, the spiral section is arranged between the first cylinder body and the first piston, and a spiral groove is provided on the outer side of the first piston. The spiral groove and the cylinder wall of the first cylinder body form a closed spiral section so that the magnetorheological fluid flows spirally along the spiral section. In this way, the spiral section is as close to the first cylinder body as possible, so that the damping force of the magnetorheological fluid can be controlled from outside the first cylinder body by using the magnetic field.

[0014] In one possible implementation manner, the permanent magnet is disposed on a magnetic ring, and the magnetic ring surrounds the outer circumference of the spiral segment. In this way, the distance is closer, and the permanent magnet can be used to generate a larger damping force.

[0015] In one embodiment, a shielding ring is provided at the lower end of the first piston, so that when the permanent magnet moves to the second position, the impact on the first channel is smaller, resulting in smaller damping.

[0016] In one embodiment, the permanent magnet is fixed under the second cylinder body and moves with the second cylinder body, the first connecting rod is provided with a second piston, the second cylinder body is provided with a second chamber, the second piston is located in the second chamber, and the first cylinder body and the second cylinder body are connected in series, so that they can be subjected to force synchronously. The magnetic ring is fixed on the second cylinder body, so the position of the permanent magnet can be moved according to the force conditions, that is, the greater the force, the greater the movement distance may be. If used in a car, the force on the car when it is driving on a flat road is also relatively stable, and the permanent magnet is in the first position. However, if the roadside is bumpy, the force on the shock absorber is unstable when the car is driving, sometimes large and sometimes small. In this way, when the force is large, the damping force can be reduced by moving the relative position of the permanent magnet to make the suspension softer and more comfortable. When the force is small, the damping force will be increased. In this way, no other control structure is required, and the moving permanent magnet can be changed in real time, and the control is convenient and quick.

[0017] In one embodiment, the second chamber is provided with a second magnetic attraction portion. When the permanent magnet is in the first position, the second magnetic attraction portion and the second piston are fixed together by magnetic attraction. In this way, the position of the permanent magnet will not change under a smaller force, and the damping force can also be maintained at a larger state. When encountering abnormal road conditions, such as raised stones or potholes, the force on the shock absorber suddenly increases. If it is greater than the magnetic force between the second magnetic attraction portion and the second piston, the permanent magnet can be moved to adjust the damping force. For a larger compression amount, the permanent magnet can be moved from the first position to the second position to minimize the damping.

[0018] In one possible implementation, the second piston is provided with a second channel, the second channel connects the two sides of the second piston, the second channel is smaller than the first channel or the flow resistance of the hydraulic oil in the second cylinder is greater than the flow resistance of the magnetorheological fluid, so that under the same force, the time required for all the hydraulic oil in the second chamber to pass through the second channel is longer than the time required for the same volume of magnetorheological fluid in the first chamber to pass through the first channel. In this way, the permanent magnet moves a smaller distance under a smaller force, and the state of the shock absorber is more stable. Magnetorheological fluid is also a kind of hydraulic oil. Magnetorheological fluid can also be set in the second cylinder body, and a second electromagnetic coil can be set in the second piston, so that the damping force of the magnetorheological fluid in the second cylinder body can be adjusted. For example, when used in a car, the damping force can be adjusted according to different road conditions. When stronger controllability is required, a larger damping force can be provided. When more comfort is required, the damping force can be reduced. The damping of the second cylinder body is smaller, and the permanent magnet can also be moved under a smaller impact to adjust the damping force of the first cylinder body. The second cylinder body not only has the function of an ordinary damping structure, but also has the function of controlling the damping of the first cylinder body. In this way, timely and automatic control of the first cylinder body can be achieved, and autonomous control can also be achieved by adjusting the current through the circuit.

[0019] In one possible implementation manner, the second piston is provided with a second electromagnetic coil, and the position of the second piston can be controlled by the second electromagnetic coil to further control the position of the permanent magnet.

[0020] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present application, nor is it intended to limit the scope of the present application. Other features of the present application will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] By reading the detailed description below with reference to the accompanying drawings, the above and other purposes, features and advantages of the exemplary embodiments of the present application will become readily understood. In the accompanying drawings, several embodiments of the present application are shown in an exemplary and non-limiting manner, wherein: In the drawings, the same or corresponding reference numerals represent the same or corresponding parts.

[0022] Figure 1 A three-dimensional schematic diagram of a magnetorheological damper according to an embodiment of the present application is shown; Figure 2 A half-section schematic diagram of the magnetorheological damper in an uncompressed state when the permanent magnet is in a first position according to an embodiment of the present application is shown; Figure 3 A half-section schematic diagram of the magnetorheological damper according to the embodiment of the present application is shown when the magnetorheological damper is compressed by a certain distance but the permanent magnet is in the first position; Figure 4 Shows Figure 3 The enlarged schematic diagram at A in the middle; Figure 5 A half-section schematic diagram of the magnetorheological damper according to the embodiment of the present application when it is compressed by a certain distance and the permanent magnet is in the second position is shown; Figure 6 Shows Figure 5 The enlarged schematic diagram of point B in the middle; Figure 7 A three-dimensional schematic diagram of a first piston and a first connecting rod of a magnetorheological shock absorber according to an embodiment of the present application is shown; Figure 8 A three-dimensional schematic diagram of a magnetorheological damper according to another embodiment of the present application is shown; Fig. 9 A half-section schematic diagram of a magnetorheological damper in another embodiment of the present application is shown in an uncompressed state when the permanent magnet is in a first position; Fig.10 A half-section schematic diagram of another embodiment of the present application when the magnetorheological damper is compressed by a certain distance and the permanent magnet is in the second position; Fig.11 A schematic transverse cross-sectional view of the position of the first channel of a magnetorheological damper according to another embodiment of the present application is shown; Fig.12 A half-section schematic diagram of the magnetorheological damper of Example 4 of the present application is shown when it is compressed a certain distance and the permanent magnet is in the second position.

[0023] Description of the numbers in the figure: 1. First cylinder; 2. First piston; 3. First connecting rod; 4. Permanent magnet; 5. First channel; 6. Second cylinder; 7. First support; 8. Second support; 10. First chamber; 11. Main chamber; 12. Sub-chamber; 13. External spring; 14. First tube; 15. Second tube; 16. Electromagnet coil; 17. Mounting plate; 18. Moving slot; 19. Inserting slot; 21. First coil; 22. Shielding ring; 31. Harness hole; 32 , second piston; 33, second channel; 34, first sleeve; 35, guide strip; 41, magnetic ring; 42, inner wall; 43, outer wall; 44, upper wall; 45, lower wall; 46, positioning through hole; 50, control section; 51, spiral section; 52, upper vertical section; 53, lower vertical section; 54, spiral groove; 61, sleeve; 62, second chamber; 63, second magnetic attraction part; 64, third magnetic attraction part; 65, reset spring; 66, second electromagnetic coil. DETAILED DESCRIPTION

[0024] In order to make the purpose, features, and advantages of the present application more obvious and easy to understand, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0025] like Figure 1-11 As shown, a magnetorheological shock absorber includes a first cylinder body 1, a first piston 2, a first connecting rod 3 and a permanent magnet 4. The first piston 2 is fixed on the first connecting rod 3. The first cylinder body 1 is provided with a first chamber 10. The first chamber 10 is provided with a magnetorheological fluid. When the first piston 2 moves in the first chamber 10, the magnetorheological fluid flows through the first channel 5. The permanent magnet 4 is arranged close to the first channel 5. The permanent magnet 4 is provided with at least a first position and a second position. The first position is closer to the first channel 5 than the second position, so that when the permanent magnet 4 is in the first position, the damping force of the shock absorber is greater than when the permanent magnet 4 is in the second position. A first support portion 7 is provided under the first cylinder body 1, and a second support portion 8 is provided under the second cylinder body 6. The first support portion 7 and the second support portion 8 are provided with mounting structures that can be installed to other structural positions where damping force needs to be provided. As shown Figure 1 As shown, the upper and lower positions of the shock absorber can be tilted, inverted or horizontally set in actual use, and the upper and lower positions are the exemplary implementation states of this embodiment.

[0026] The magnetorheological shock absorber of the present application can be used not only as a shock absorber for automobiles, but also as a damper for other mechanical equipment, and has more obvious technical advantages when used in shock absorbers for automobiles.

[0027] The movement of the permanent magnet 4 can be achieved by means of a reduction motor, a cylinder, a hydraulic cylinder or an electromagnet, but a control structure needs to be set up and a corresponding control judgment logic is required, so it is relatively complicated. If it is driven directly by the shock absorber force, a more stable switching movement can be achieved. The existing magnetorheological shock absorber needs to be continuously powered when it needs to provide greater damping, and most of the time, the suspension needs to be kept in a harder state due to the need for better controllability, which consumes a lot of electricity, and when there is a sudden pit or bump on the road surface, the damping force cannot be changed immediately, causing the vehicle to jump off the ground and lose control performance.

[0028] Embodiment 1: like Figure 1-7 As shown, the first chamber 10 is divided into a main chamber 11 and a sub-chamber 12 by a control section 50, and the first channel 5 is located in the control section 50 so that the main chamber 11 and the sub-chamber 12 are connected through the first channel 5. The control section 50 is located at the first piston 2, that is, the first channel 5 is processed in the first piston 2. The movement of the first piston 2 can change the volume of the main chamber 11 and the sub-chamber 12, so that the magnetorheological fluid can flow, but it must flow through the first channel 5. The structure of magnetic field control is set in the first channel 5 to realize the control of the damping force. The greater the magnetic field strength, the greater the damping force.

[0029] like Figure 3-7 As shown, in one embodiment, the first channel 5 includes a spiral section 51, an upper vertical section 52 and a lower vertical section 53, the upper vertical section 52 and the lower vertical section 53 are arranged along the axial direction, the spiral section 51 is arranged to extend along the axial direction spirally, and the upper vertical section 52 and the lower vertical section 53 are located at both ends of the spiral section 51. For the convenience of processing, the cross section of the spiral section 51 is rectangular, and the cross sections of the upper vertical section 52 and the lower vertical section 53 are circular. The upper vertical section 52 and the lower vertical section 53 can be provided with a plurality of circular holes to connect the spiral section 51 with the main chamber 11 and the auxiliary chamber 12, that is, an axial through hole can be opened on the first piston 2.

[0030] like Figure 3-7 As shown, in one embodiment, the spiral section 51 is arranged between the first cylinder body 1 and the first piston 2, and the outer side surface of the first piston 2 is provided with a spiral groove 54, and the spiral groove 54 and the cylinder wall of the first cylinder body 1 form a closed spiral section 51 so that the magnetorheological fluid flows spirally along the spiral section 51. The first coil 21 is arranged inside the first piston 2, and the central axis of the first coil 21 is located at the central axis of the first piston 2. The first connecting rod 3 is provided with a harness hole 31 to install a wire to power the first coil 21, and the magnitude of the damping force can be adjusted by changing the magnitude of the current. The magnetic induction lines generated by the first coil 21 in the upper vertical section 52 and the lower vertical section 53 are basically horizontal, that is, perpendicular to the flow direction of the magnetorheological fluid, and the magnetic induction lines generated in the spiral section 51 are vertical, also perpendicular to the flow direction of the magnetorheological fluid, so that it has a better damping effect.

[0031] like Figure 3-7 As shown, in one embodiment, the permanent magnet 4 is arranged on the magnetic ring 41, and the magnetic ring 41 surrounds the outer circumference of the spiral segment 51. The permanent magnet 4 can be an annular magnet or an annularly distributed magnet. The permanent magnet 4 is radially magnetized to form an annular magnet, so that the magnetic field direction inside the annular magnet is radial, that is, pointing to the center of the circle, so that the direction of the magnetic flux line is perpendicular or nearly perpendicular to the flow direction of the magnetorheological fluid of the spiral segment 51, so that the damping force generated is greater.

[0032] like Figure 3-7 As shown, in one embodiment, a shielding ring 22 is provided at the lower end of the first piston 2. The magnetic ring 41 is wrapped around the permanent magnet 4, and the magnetic ring 41 includes an inner wall 42, an outer wall 43, an upper wall 44 and a lower wall. The inner wall 42 is located at the innermost side close to the first cylinder body 1, and the outer wall 43 is far away from the first cylinder body 1. The upper wall 44 is located on the upper side, and the lower wall is located on the lower side. The inner wall 42, the outer wall 43, the upper wall 44 and the lower wall 45 form a closed structure. The inner wall 42 and the lower wall 45 are made of non-ferromagnetic materials, such as copper or aluminum, the upper wall 44 is made of ferromagnetic materials, and the outer wall 43 can be made of various materials. In order to reduce the distance between the permanent magnet 4 and the first channel 5, the inner wall 42 can be cancelled, and the permanent magnet 4 can be fixed on the outer wall 43 or the upper wall 44, the lower wall 45 and other structures.

[0033] like Figure 2 As shown, at this time, the shock absorber is not compressed, and the permanent magnet 4 is located at the first position close to the first channel 5, which can generate a larger damping force. The damping force can be further increased by increasing the magnetic field strength through the first coil 21.

[0034] like Figure 3-7 As shown, in one embodiment, the shock absorber is provided with a second cylinder body 6, the magnetic ring 41 is fixed under the second cylinder body 6 and moves with the second cylinder body 6, the second cylinder body 6 is connected to the magnetic ring 41 through a sleeve 61, the first connecting rod 3 is provided with a second piston 32, the second cylinder body 6 is provided with a second chamber 62, and the second piston 32 is located in the second chamber 62.

[0035] like Figure 3-7As shown, in one embodiment, the second chamber 62 is provided with a second magnetic attraction portion 63, and the second magnetic attraction portion 63 and the second piston 32 are fixed together by magnetic attraction. Magnetic attraction can be achieved by arranging a magnet in the second magnetic attraction portion 63 and using ferromagnetic material to manufacture the second piston 32, or arranging a magnet in the second piston 32 and using ferromagnetic material to manufacture the second magnetic attraction portion 63. In this way, when the shock absorber is subjected to a small force, the second magnetic attraction portion 63 and the second piston 32 will not separate, the permanent magnet 4 can be maintained in the first position, and the shock absorber can maintain the damping force. When the shock absorber is subjected to a large force, the second magnetic attraction portion 63 is separated from the second piston 32, the permanent magnet 4 can move to the second position, and the shock absorber reduces the damping force. The closer the permanent magnet 4 is to the second position, the smaller the damping force. The movement of the permanent magnet 4 is continuous, so the change of the damping force is continuous.

[0036] In one embodiment, the second chamber 62 is provided with hydraulic oil or magnetorheological fluid to generate a damping force on the movement of the second piston 32. The second piston 32 is provided with a second channel 33, the second channel 33 connects the two sides of the second piston 32, the second channel 33 is smaller than the first channel 5 or the flow resistance of the hydraulic oil in the second cylinder 6 is greater than the flow resistance of the magnetorheological fluid, so that under the same force, the time required for all the hydraulic oil in the second chamber 62 to pass through the second channel 33 is longer than the time required for the same volume of magnetorheological fluid in the first chamber 10 to pass through the first channel 5.

[0037] like Figure 2 and Figure 3As shown, when the permanent magnet 4 is in the first position, the second magnetic attraction part 63 and the second piston 32 are attracted together by magnetic force, so the hydraulic oil in the second chamber 62 has a small area on the second magnetic attraction part 63, which is only the area of ​​the second channel 33. Even if the pressure in the second chamber 62 is large, the separation force on the second magnetic attraction part 63 is small, which is equal to the product of the cross-sectional area of ​​the second channel 33 and the pressure in the second chamber 62. Therefore, it is difficult to separate the second magnetic attraction part 63 from the second piston 32. Only when the separation force is greater than the magnetic attraction force can the second magnetic attraction part 63 be separated from the second piston 32. A return spring 65 is provided in the second chamber 62, and the separation force needs to overcome the force of the return spring 65. This structure has the effect of a lever, that is, when a force of 100 N is applied between the second cylinder 6 and the first connecting rod 3, if the ratio of the cross-sectional area of ​​the second channel 33 to the cross-sectional area of ​​the second chamber 62 is 1:10, the separation force is only 10 N, and the external force of the shock absorber is mainly absorbed by the outer spring 13. When the shock absorber is extended or retracted, the first connecting rod 3 and the first cylinder 1 or the second cylinder 6 will generate a larger force. For example, when the vehicle travels on a bumpy road section, the shock absorber retracts or retracts quickly. The faster the speed, the greater the damping force, and the greater the force between the first connecting rod 3 and the first cylinder 1 or the second cylinder 6. In this way, when the vehicle is traveling on a flat road, the permanent magnet 4 can be maintained in the first position. When the vehicle suddenly encounters a bumpy road surface, there is a larger force between the first connecting rod 3 and the first cylinder 1 and the second cylinder 6, and the second piston 32 moves relative to the second cylinder 6, and the permanent magnet 4 also moves.

[0038] like Figure 3 and Figure 4 As shown, when the shock absorber shrinks slowly and the separation force is small, the permanent magnet 4 is kept in the first position. At this time, the damping force generated by the magnetorheological fluid in the first cylinder 1 under the action of the permanent magnet 4 is large.

[0039] like Figure 5 and Figure 6 As shown, when the shock absorber contracts at a faster speed, the separation force is larger, and the permanent magnet 4 moves to the second position. At this time, the magnetorheological fluid is away from the permanent magnet 4, and the upper wall 44 and the shielding ring 22 can shield a large amount of magnetic field. The damping force generated by the magnetorheological fluid under the action of a smaller magnetic field is smaller. At this time, the shock absorber is compressed by a certain distance, and the stroke can be quickly restored after the external force is removed. The outer spring 13 is compressed by a certain distance, and further compression of the outer spring 13 requires a larger force. Even if the damping force is small, the shock absorber can have a better support performance.

[0040] like Figure 7 As shown, the spiral groove 54 is located on the outer side of the first piston 2. The first piston 2 can be provided with a plurality of upper vertical sections 52 and lower vertical sections 53, that is, a through hole connected to the spiral groove 54 is provided on the end surface of the first piston 2. The second piston 32 is provided with a second channel 33.

[0041] Embodiment 2: like Figure 8 As shown, the shock absorber is provided with a first support portion 7 and a second support portion 8, and the first support portion 7 and the second support portion 8 are provided with mounting structures that can be mounted to other structural positions that need to provide damping force.

[0042] like Figure 8-11 As shown, the first cylinder body 1 adopts a double-tube structure, including a first tube 14 and a second tube 15. The first chamber 10 is divided into a main chamber 11 and a sub-chamber 12 by a control section 50. The main chamber 11 is located on the inner side of the first tube 14, and the sub-chamber 12 is located between the first tube 14 and the second tube 15. The first channel 5 is located in the control section 50 so that the main chamber 11 and the sub-chamber 12 are connected through the first channel 5. The control section 50 is located at the lower end of the first cylinder body 1, that is, the lower end of the first tube 14 and the second tube 15. The first channel 5 is a planar spiral structure. A permanent magnet 4 is provided below the first channel 5, and the permanent magnet 4 can move radially. An electromagnet coil 16 is provided above the first channel 5. When the current of the electromagnet coil 16 changes, the magnetic field strength also changes, thereby adjusting the damping force of the magnetorheological fluid. Of course, the permanent magnet 4 is usually used to increase the damping force, but when the damping force needs to be further increased, the magnetic field strength can be strengthened by positive power supply, and when the damping force needs to be reduced, the magnetic field strength can be reduced by reverse power supply. When the permanent magnet 4 moves radially to the outside, the damping force is controlled only by the electromagnet coil 16, and the current size can be adjusted.

[0043] The permanent magnet 4 is provided with a positioning through hole 46, a mounting plate 17 is provided below the first cylinder body 1, the mounting plate 17 is provided with a moving groove 18 and a through-slot 19, the permanent magnet 4 is installed in the moving groove 18, the permanent magnet 4 moves radially to realize the switching from the second position to the first position, the main chamber 11 is provided with a first piston 2, the first piston 2 is provided with a first connecting rod 3, the first connecting rod 3 is directly or indirectly fixed to the first sleeve 34, the lower end of the first sleeve 34 is provided with a guide bar 35, the guide bar 35 is provided with a plurality of circumferentially arranged outside the first sleeve 34, in order to avoid affecting the installation of the shock absorber, the guide bar 35 is not provided in some directions, and some sections of the guide bar 35 are arranged in the through-slot 19 and inserted into the positioning through hole 46. The guide bar 35 is axially extended and has different radial distances at some positions, so that the axial movement of the guide bar 35 can make the permanent magnet 4 move radially.

[0044] like Fig. 9 and Fig.10 As shown, in order to ensure that the permanent magnet 4 has a larger moving space, the first position is arranged closer to the center than the second position. Fig. 9 As shown, when the first piston 2 is in the initial position, the permanent magnet 4 is in the first position, and the guide bar 35 is also in a higher position, as shown in FIG. Fig.10As shown, the first piston 2 moves downward, and the guide bar 35 also moves downward a certain distance. At this time, the permanent magnet 4 moves outward to the second position, and the magnetic field strength received by the first channel 5 decreases, and the damping force also decreases.

[0045] Embodiment 3: like Figure 8-11 As shown, a second cylinder 6 is provided above the first cylinder 1. When the second cylinder 6 moves relative to the first connecting rod 3, it can drive the permanent magnet 4 to move. A magnetorheological fluid is provided in the second cylinder 6. The second piston 32 is provided with a second electromagnetic coil 66. The second electromagnetic coil 66 can control the damping force of the magnetorheological fluid. The second cylinder 6 is provided with a second magnetic attraction portion 63 and a third magnetic attraction portion 64. When a larger damping force is required, the second electromagnetic coil 66 is energized to increase the damping force of the magnetorheological fluid. In addition, the adsorption force with the second magnetic attraction portion 63 can also be increased, so that it has better supporting performance. When it is necessary to reduce the damping, the second electromagnetic coil 66 is powered off. Under a smaller force, the second piston 32 can move relative to the second cylinder 6, that is, the permanent magnet 4 can be moved, and the damping force of the first cylinder 1 can be changed. When the second piston 32 is close to the third magnetic attraction portion 64, the second electromagnetic coil 66 can be energized, so that it can be adsorbed on the third magnetic attraction portion 64, and there is a larger damping force in the second cylinder 6, so as to prevent the permanent magnet 4 from moving from the second position to the first position.

[0046] Embodiment 4: like Fig.12 As shown, a second cylinder 6 is provided above the first cylinder 1. When the second cylinder 6 moves relative to the first connecting rod 3, it can drive the permanent magnet 4 to move. Hydraulic oil is provided in the second cylinder 6. The second piston 32 is provided with a second electromagnetic coil 66. When the second electromagnetic coil 66 is energized, the second piston 32 has a magnetic attraction force. The second cylinder 6 is provided with a second magnetic attraction portion 63 and a third magnetic attraction portion 64. The second magnetic attraction portion 63 and the third magnetic attraction portion 64 are magnets. The second electromagnetic coil 66 can adjust the position of the second piston 32 by energizing it in the forward and reverse directions. For example, it can be adsorbed to the second magnetic attraction portion 63 when it is energized in the forward direction, and it can be adsorbed to the third magnetic attraction portion 64 when it is energized in the reverse direction. In this way, the position of the permanent magnet 4 can be adjusted by the electromagnet structure. Of course, when the shock absorber is rapidly extended and retracted, even if the second electromagnetic coil 66 is energized, due to the large force, the second piston 32 will be separated from the second magnetic attraction portion 63. In this way, the vehicle will have better comfort when it is actually used, that is, when encountering a raised road surface, the damping force can be adjusted more quickly to make the vehicle body more stable.

[0047] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, "plurality" means two or more, unless otherwise clearly and specifically defined. It is also generally possible to place the shock absorber upside down or horizontally, so the up and down directions are relative directions and not directions actually used. In each embodiment, the up and down directions in the drawings are used as relative directions for introduction.

[0048] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A magnetorheological damper, comprising a first cylinder (1), a first piston (2), a first connecting rod (3) and a permanent magnet (4), wherein the first piston (2) is fixed to the first connecting rod (3), the first cylinder (1) is provided with a first chamber (10), the first chamber (10) is provided with a magnetorheological fluid, and when the first piston (2) moves in the first chamber (10), the magnetorheological fluid flows through a first channel (5), characterized in that: The permanent magnet (4) is arranged close to the first channel (5), and the permanent magnet (4) is provided with at least a first position and a second position. The permanent magnet (4) is closer to the first channel (5) when it is located at the first position than when it is located at the second position, so that when the permanent magnet (4) is in the first position, the damping force of the magnetorheological damper is greater than when the permanent magnet (4) is in the second position.

2. The magnetorheological damper according to claim 1, characterized in that: The first chamber (10) is divided into a main chamber (11) and a sub-chamber (12) by a control section (50); the first channel (5) is located in the control section (50) so that the main chamber (11) and the sub-chamber (12) are connected through the first channel (5); and the control section (50) is located at the first piston (2) or at the upper end or the lower end of the first cylinder body (1).

3. The magnetorheological damper according to claim 2, characterized in that: The first channel (5) comprises a spiral section (51), an upper vertical section (52) and a lower vertical section (53); the upper vertical section (52) and the lower vertical section (53) are arranged along the axial direction; the spiral section (51) is arranged to extend in a spiral manner along the axial direction; the upper vertical section (52) and the lower vertical section (53) are located at two ends of the spiral section (51).

4. The magnetorheological damper according to claim 3, characterized in that: The spiral section (51) is arranged between the first cylinder body (1) and the first piston (2); a spiral groove (54) is provided on the outer side surface of the first piston (2); the spiral groove (54) and the cylinder wall of the first cylinder body (1) form a closed spiral section (51) so that the magnetorheological fluid flows in a spiral along the spiral section (51).

5. The magnetorheological damper according to claim 4, characterized in that: The permanent magnet (4) is arranged on a magnetic ring (41), and the magnetic ring (41) surrounds the outer circumference of the spiral segment (51).

6. The magnetorheological damper according to any one of claims 1 to 5, characterized in that: The permanent magnet (4) is fixed below the second cylinder body (6) and moves with the second cylinder body (6); the first connecting rod (3) is provided with a second piston (32); the second cylinder body (6) is provided with a second chamber (62); and the second piston (32) is located in the second chamber (62).

7. The magnetorheological damper according to claim 6, characterized in that: The second chamber (62) is provided with a second magnetic attraction portion (63), and when the permanent magnet (4) is located at the first position, the second magnetic attraction portion (63) and the second piston (32) are fixed together by magnetic attraction.

8. The magnetorheological damper according to claim 7, characterized in that: The second piston (32) is provided with a second channel (33), the second channel (33) being connected to the upper and lower sides of the second piston (32), the second channel (33) being smaller than the first channel (5) or the flow resistance of the hydraulic oil in the second cylinder (6) being larger than the flow resistance of the magnetorheological fluid, so that under the same force, the time required for all the hydraulic oil in the second chamber (62) to pass through the second channel (33) is longer than the time required for the same volume of magnetorheological fluid in the first chamber (10) to pass through the first channel (5).

9. The magnetorheological damper according to claim 8, characterized in that: A shielding ring (22) is provided at the lower end of the first piston (2).

10. The magnetorheological damper according to claim 9, characterized in that: The second piston (32) is provided with a second electromagnetic coil (66).

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