A magneto-rheological shock absorber

Abstract

The present application provides a magnetorheological shock absorber, which includes 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, and the first chamber is provided with 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 has at least a first position and a second position. The first position is closer to the first channel than the second position, so that the damping force of the shock absorber when the permanent magnet is in the first position is greater than that when the permanent magnet is in the second position. When the permanent magnet is in the first position, the permanent magnet is closer to the first channel, and a higher magnetic field intensity is generated near the first channel. The magnetorheological fluid generates a greater damping force under the action of a larger magnetic field. When the permanent magnet is in the second position, the magnetorheological fluid has a smaller damping force under the action of a smaller magnetic field.

Description

Technical Field

[0001] The present application relates to the field of shock absorbers and the field of electromagnetic technology, and particularly relates to a magnetorheological shock absorber. Background Art

[0002] During the driving process of an automobile, due to the uneven road surface, the vertical reaction force, longitudinal reaction force, and lateral reaction force acting on the wheels fluctuate, and are transmitted to the vehicle body through the suspension, thereby generating vibrations and impacts. When these vibrations and impacts are transmitted to the frame and the vehicle body, they may cause early damage to the automobile components. When transmitted to the passengers and goods, the passengers will feel extremely uncomfortable, and the goods may also be damaged, seriously affecting the ride comfort, handling stability of the vehicle, and the fatigue life of vehicle components. In order to alleviate the impact, elastic elements are installed in the automobile suspension, but the elastic system generates vibrations during impacts. Continuous vibrations are likely to make passengers feel uncomfortable and fatigued. Therefore, dampers are installed in the automobile suspension.

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

[0004] As an actuator of a semi-active control suspension, a magnetorheological shock absorber uses magnetorheological fluid as the medium. By controlling the input current, the external magnetic field strength is changed, and then the rheological properties of the magnetorheological fluid can be changed within milliseconds, realizing the transformation between fluid and semi-solid, and thus capable of providing controllable damping force. It has the advantages of simple structure, convenient control, rapid response, low power consumption, and large output force.

[0005] When driving on urban roads, under normal circumstances, the road surface is relatively flat. Therefore, a harder suspension is required, which has better handling performance, shorter braking distance, and better steering performance. The greater the magnetic field strength, the greater the damping force, but the more electrical energy is consumed. However, for the current road conditions in China, flat roads are far more than potholed roads. Therefore, a larger magnetic field needs to be provided most of the time during daily driving to ensure a greater damping force.

[0006] The patent with the Chinese patent authorization announcement number "CN106678256B" and the patent name "An electromagnetic self-powered suspension shock absorber for electric vehicles" discloses a structure of a magnetorheological shock absorber. Although a permanent magnet is provided, its main consideration is energy recovery rather than the adjustment of damping force.

[0007] The patent with the Chinese patent authorization announcement number "CN221278333U" and the patent name "New Type Magnetorheological Automobile Shock Absorber" discloses a magnetorheological shock absorber. Its permanent magnet 13 is fixed inside the piston cylinder 1. When the piston 11 descends, it will drive the telescopic shaft sleeve 14 to fold downward through the connecting rod 12. After the telescopic shaft sleeve 14 folds downward, the magnetic field force of the internal permanent magnet 13 will be gradually exposed. As more of the permanent magnet 13 is exposed, the intensity of the magnetic field becomes stronger. 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 completely different from the design of the magnetorheological shock absorber that actually needs to be regulated. Especially in terms of the performance on a flat road, in order to have better braking performance and steering performance, the shock absorber needs to have a large damping force at any position to avoid phenomena such as braking nod and serious tilting of the vehicle during turning. However, the technical solution of this patent is the same as the function of an ordinary spring, that is, the greater the compression, the greater the damping force. In this way, the recovery stroke also becomes slow at the position with a large compression, that is, when the vehicle is driving on a bumpy road surface, the shock absorber will shorten and harden, resulting in a significant decrease in comfort. Theoretically, the shock absorber has better elasticity and higher comfort on a bumpy road surface. Therefore, this design has poor comfort. If a large damping force is required at the initial position, it needs to be achieved by relying on an electromagnet, which is the same as the performance of an ordinary magnetorheological shock absorber. Summary of the Invention

[0008] The present application provides a magnetorheological shock absorber 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, which includes 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 magnetorheological fluid, and 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 has at least a first position and a second position. The distance from the permanent magnet in the first position to the first channel is closer than that from the permanent magnet in the second position to the first channel, 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 shock absorber of the present application has the following beneficial effects:

[0011] 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 greater damping force under the action of a larger magnetic field. When the shock absorber is used in an automobile, the suspension can be made harder and the vehicle handling performance can be better. Since the use of a permanent magnet does not require power supply, it is more energy-efficient compared to electromagnetic coil control. When the permanent magnet is in the second position, the permanent magnet is farther from the first channel, and the magnetic field intensity generated near the first channel is smaller. The magnetorheological fluid generates a smaller damping force under the action of a smaller magnetic field. When the shock absorber is used in an automobile, the suspension can be made softer and the vehicle comfort can be better. The movement of the permanent magnet can be achieved by conventional means such as a reduction motor, a cylinder, a hydraulic cylinder, or an electromagnet, or a more ingenious structure can be designed to achieve it, making the structure simpler, more energy-efficient, and environmentally friendly. The shock absorber can also be used as a damper in other mechanical structures.

[0012] In an implementable 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 block. Such a design makes the structure more compact.

[0013] In an implementable 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 extends helically along the axis. 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 induction lines are in the horizontal direction at the positions of the upper vertical section and the lower vertical section, while the magnetic induction lines are in the vertical direction in the spiral section. This can make the magnetic induction lines perpendicular to the flow direction of the magnetorheological fluid, resulting in a better damping effect.

[0014] In an implementable embodiment, the spiral section is arranged between the first cylinder block and the first piston. A spiral groove is provided on the outer side surface of the first piston. The spiral groove and the cylinder wall of the first cylinder block 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 as possible to the first cylinder block, which is convenient for controlling the damping force of the magnetorheological fluid from the outside of the first cylinder block using the magnetic field.

[0015] In an implementable embodiment, the permanent magnet is arranged on a magnetic ring, and the magnetic ring surrounds the outer periphery of the spiral section. In this way, the distance is closer, and a larger damping force can be generated using the permanent magnet.

[0016] In an implementable embodiment, a shielding ring is provided at the lower end of the first piston. In this way, when the permanent magnet moves to the second position, the influence on the first channel is smaller, resulting in a smaller damping.

[0017] In an implementable embodiment, the permanent magnet is fixed below 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 stressed synchronously. The magnetic ring is fixed on the second cylinder body. Therefore, the position of the permanent magnet can be moved according to the stress situation, that is, the greater the stress, the greater the possible moving distance. If it is used in an automobile, when the automobile is driving on a flat road surface, the stress is relatively stable, and the permanent magnet is in the first position. However, if the roadside is relatively potholed, the shock absorber is stressed unstably when the automobile is driving, sometimes large and sometimes small. In this way, when the stress is large, the relative position of the permanent magnet can be moved to reduce the damping force, making the suspension softer and more comfortable. When the stress is small, the damping force will be increased. In this way, no other control structure is required, and the permanent magnet can be moved in real time, and the control is convenient and fast.

[0018] In an implementable embodiment, the second chamber is provided with a second magnetic attraction part. When the permanent magnet is in the first position, the second magnetic attraction part and the second piston are fixed together by magnetic attraction, so that the position of the permanent magnet will not change under a small acting force, and the damping force can also be maintained at a large state. When encountering abnormal road conditions, such as a raised stone or a pothole, the stress on the shock absorber suddenly increases. If it is greater than the magnetic force between the second magnetic attraction part and the second piston, the permanent magnet can be moved to adjust the damping force. For a large compression amount, the permanent magnet can move from the first position to the second position, reducing the damping to the lowest.

[0019] In an implementable embodiment, the second piston is provided with a second channel, and the second channel communicates with both 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 body is greater than the flow resistance of the magnetorheological fluid, so that the time required for all the hydraulic oil in the second chamber to pass through the second channel under the same acting force is more than the time required for the same volume of magnetorheological fluid in the first chamber to pass through the first channel. In this way, under a small acting force, the moving distance of the permanent magnet is small, and the state of the shock absorber is more stable. The magnetorheological fluid also belongs to a kind of hydraulic oil. The magnetorheological fluid can also be provided in the second cylinder body, and a second electromagnetic coil is provided on the second piston. In this way, the damping force of the magnetorheological fluid in the second cylinder body can be adjusted. If it is used in an automobile, the damping force can be adjusted according to different road conditions. When strong controllability is required, a larger damping force can be provided. When more comfort and reduced damping force are required, the damping of the second cylinder body is smaller, and the permanent magnet can also be moved under a small impact to realize the adjustment of 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, the timely automatic control of the first cylinder body can be realized, and the independent control can also be realized by adjusting the current through the circuit.

[0020] In an implementable embodiment, the second piston is provided with a second electromagnetic coil, and the position of the second piston can be controlled through the second electromagnetic coil to further realize the control of the position of the permanent magnet.

[0021] 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 used to limit the scope of the present application. Other features of the present application will become readily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] By referring to the drawings and reading the following detailed description, the above and other objects, features, and advantages of the exemplary embodiments of the present application will become readily understandable. In the drawings, several embodiments of the present application are shown in an exemplary rather than restrictive manner, wherein:

[0023] In the drawings, the same or corresponding reference numerals denote the same or corresponding parts.

[0024] Figure 1 A three-dimensional schematic diagram of the magnetorheological damper according to an embodiment of the present application is shown;

[0025] Figure 2 A semi-sectional schematic diagram of the magnetorheological damper according to an embodiment of the present application in an uncompressed state with the permanent magnet in the first position is shown;

[0026] Figure 3 A semi-sectional schematic diagram of the magnetorheological damper according to an embodiment of the present application compressed by a certain distance but with the permanent magnet in the first position is shown;

[0027] Figure 4 Shows Figure 3 An enlarged schematic diagram at A in

[0028] Figure 5 A semi-sectional schematic diagram of the magnetorheological damper according to an embodiment of the present application compressed by a certain distance and with the permanent magnet in the second position is shown;

[0029] Figure 6 Shows Figure 5 An enlarged schematic diagram at B in

[0030] Figure 7 A three-dimensional schematic diagram of the first piston and the first connecting rod of the magnetorheological damper according to an embodiment of the present application is shown;

[0031] Figure 8 A three-dimensional schematic diagram of the magnetorheological damper according to another embodiment of the present application is shown;

[0032] Figure 9 A semi-sectional schematic diagram of the magnetorheological damper according to another embodiment of the present application in an uncompressed state with the permanent magnet in the first position is shown;

[0033] Figure 10 A semi-sectional schematic diagram of the magnetorheological damper according to another embodiment of the present application compressed by a certain distance and with the permanent magnet in the second position is shown;

[0034] Figure 11 Shows a schematic cross-sectional view of the first channel position of a magnetorheological shock absorber according to another embodiment of the present application;

[0035] Figure 12 Shows a half-sectional view of the magnetorheological shock absorber according to Embodiment 4 of the present application when it is compressed by a certain distance and the permanent magnet is in the second position.

[0036] Explanation of the reference numerals in the figure:

[0037] 1. First cylinder; 2. First piston; 3. First connecting rod; 4. Permanent magnet; 5. First channel; 6. Second cylinder; 7. First support part; 8. Second support part; 10. First chamber; 11. Main chamber; 12. Auxiliary chamber; 13. Outer spring; 14. First tube; 15. Second tube; 16. Electromagnet coil; 17. Mounting plate; 18. Moving groove; 19. Interpenetrating groove; 21. First coil; 22. Shielding ring; 31. Wiring 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 attracting part; 64. Third magnetic attracting part; 65. Return spring; 66. Second electromagnetic coil. Detailed implementation manners

[0038] To make the objectives, features, and advantages of the present application more obvious and understandable, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection of the present application.

[0039] As Figure 1-11 shown, a magnetorheological shock absorber includes a first cylinder 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 1 is provided with a first chamber 10, and the first chamber 10 is filled with 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 has 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 the damping force of the shock absorber when the permanent magnet 4 is in the first position is greater than the damping force of the shock absorber when the permanent magnet 4 is in the second position. A first support part 7 is provided below the first cylinder 1, and a second support part 8 is provided on the second cylinder 6. The first support part 7 and the second support part 8 are provided with mounting structures that can be mounted to other positions that need to provide damping force. AsFigure 1 As shown, the upper and lower orientations of the shock absorber can be inclined, inverted, or horizontally arranged during actual use, and the upper and lower orientations are the implementation states demonstrated in this embodiment.

[0040] The magnetorheological shock absorber of the present application can not only be used as an automotive shock absorber, but also as a damper for other mechanical equipment. In particular, it has more obvious technical advantages when used in automotive shock absorbers.

[0041] The movement of the permanent magnet 4 can be achieved by means of a reduction motor, a cylinder, a hydraulic cylinder, or an electromagnet, etc., but a control structure needs to be set up, and corresponding control judgment logic is required, so it is relatively complex. If it is directly driven by the force on the shock absorber, a more stable switching movement can be achieved. When the existing magnetorheological shock absorber needs to provide a large damping force, it needs to be continuously powered on. And most of the time, due to the need for good maneuverability, the suspension needs to be in a relatively hard state, which requires a large amount of electrical energy, and when there is a sudden pothole or bump on the road surface, the damping force cannot be changed immediately, causing the vehicle to jump off the ground and lose its maneuverability.

[0042] Embodiment 1:

[0043] As Figure 1-7 shown, the first chamber 10 is separated 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. The control section 50 is located at the first piston 2, that is, the first channel 5 is machined on the first piston 2. The movement of the first piston 2 can change the volumes of the main chamber 11 and the sub-chamber 12. In this way, the magnetorheological fluid can flow, but it must flow through the first channel 5. By setting a magnetic field control structure in the first channel 5, the control of the damping force can be achieved. The greater the magnetic field strength, the greater the damping force.

[0044] As Figure 3-7 shown, in an 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 axially, and the spiral section 51 extends axially in a spiral shape. The upper vertical section 52 and the lower vertical section 53 are located at both ends of the spiral section 51. For convenient 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. Multiple circular holes can be provided in the upper vertical section 52 and the lower vertical section 53 to connect the spiral section 51 with the main chamber 11 and the sub-chamber 12, that is, axial through holes can be drilled on the first piston 2.

[0045] As Figure 3-7As shown, in one embodiment, a spiral section 51 is provided between the first cylinder block 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 block 1 form a closed spiral section 51 such that the magnetorheological fluid flows spirally along the spiral section 51. A first coil 21 is provided inside the first piston 2. The central axis of the first coil 21 is located on the central axis of the first piston 2. A wire harness hole 31 is provided inside the first connecting rod 3 and can install a wire to supply power to the first coil 21. By changing the magnitude of the current, the magnitude of the damping force can be adjusted. The first coil 21 is arranged such that the magnetic induction lines generated in the upper vertical section 52 and the lower vertical section 53 are basically in the horizontal direction, that is, perpendicular to the flow direction of the magnetorheological fluid. The magnetic induction lines generated in the spiral section 51 are in the vertical direction, also perpendicular to the flow direction of the magnetorheological fluid, so that a better damping effect is achieved.

[0046] As Figure 3-7 shown, in one embodiment, a permanent magnet 4 is provided on a magnetic ring 41. The magnetic ring 41 surrounds the outer periphery of the spiral section 51. The permanent magnet 4 can be an annular magnet or magnets distributed in an annular shape. The permanent magnet 4 is radially magnetized to form an annular magnet such that the magnetic field direction inside the annular magnet is radial, that is, pointing to the center of the circle. In this way, the direction of the magnetic induction lines is perpendicular or nearly perpendicular to the flow direction of the magnetorheological fluid in the spiral section 51, so that a greater damping force is generated.

[0047] As Figure 3-7 shown, in one embodiment, a shielding ring 22 is provided at the lower end of the first piston 2. The magnetic ring 41 wraps around the permanent magnet 4. 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 on the innermost side close to the first cylinder block 1, the outer wall 43 is away from the first cylinder block 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 material. The outer wall 43 can be made of various materials. 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.

[0048] As Figure 2 shown, at this time, the shock absorber is not compressed. The permanent magnet 4 is located at a first position close to the first channel 5 and can generate a greater damping force. The magnetic field intensity can also be increased through the first coil 21 to further expand the damping force.

[0049] As Figure 3-7 shown, in one embodiment, the shock absorber is provided with a second cylinder block 6. The magnetic ring 41 is fixed below the second cylinder block 6 and moves with the second cylinder block 6. The second cylinder block 6 and the magnetic ring 41 are connected by a sleeve 61. The first connecting rod 3 is provided with a second piston 32. The second cylinder block 6 is provided with a second chamber 62. The second piston 32 is located inside the second chamber 62.

[0050] As Figure 3-7 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 providing a magnet in the second magnetic attraction portion 63 and manufacturing the second piston 32 with a ferromagnetic material, or by providing a magnet in the second piston 32 and manufacturing the second magnetic attraction portion 63 with a ferromagnetic material. With this arrangement, 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 at 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 and the second piston 32 separate, 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 in the damping force is continuous.

[0051] In one embodiment, the second chamber 62 is provided with hydraulic oil or magnetorheological fluid that can 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 communicates with both 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 the time required for all the hydraulic oil in the second chamber 62 to pass through the second channel 33 under the same acting force is more than the time required for the same volume of magnetorheological fluid in the first chamber 10 to pass through the first channel 5.

[0052] As 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. Therefore, the acting area of the hydraulic oil in the second chamber 62 on the second magnetic attraction part 63 is small, only the area of the second channel 33. Even if the pressure in the second chamber 62 is large, the separating 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 very difficult to separate the second magnetic attraction part 63 from the second piston 32, and only when the separating 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, so the separating force also needs to overcome the force of the return spring 65. This structure has the function of a lever, that is, when a force of 100 N is applied between the second cylinder body 6 and the first connecting rod 3, assuming 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 separating force received is only 10 N. The external force of the shock absorber is mainly absorbed by the outer spring 13. When the shock absorber expands and contracts, a large force will be generated between the first connecting rod 3 and the first cylinder body 1 or the second cylinder body 6. For example, when the vehicle drives on a potholed road section, the shock absorber expands and contracts 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 body 1 or the second cylinder body 6. In this way, when the vehicle is driving on a flat road, the permanent magnet 4 can be kept in the first position. When the vehicle suddenly encounters a potholed road surface, a large force will be generated between the first connecting rod 3 and the first cylinder body 1 and the second cylinder body 6. The second piston 32 moves relative to the second cylinder body 6, and then the permanent magnet 4 also moves.

[0053] As Figure 3 and Figure 4 shown, when the shock absorber contracts at a slow speed, the separating force is small, and the permanent magnet 4 remains in the first position. At this time, the damping force generated by the magnetorheological fluid on the first cylinder body 1 under the action of the permanent magnet 4 is large.

[0054] As Figure 5 and Figure 6 shown, when the shock absorber contracts at a fast speed, the separating force is large, and the permanent magnet 4 moves to the second position. At this time, the magnetorheological fluid is far away from the permanent magnet 4, and the upper wall 44 and the shielding ring 22 can shield a large amount of magnetic fields. The damping force generated by the magnetorheological fluid under the action of a small magnetic field is small. At this time, the shock absorber is compressed by a certain distance and can quickly recover its stroke after the external force is removed. The outer spring 13 is compressed by a certain distance, and a larger force is required to further compress the outer spring 13. Even if the damping force is small, the shock absorber can still have good supporting performance.

[0055] As Figure 7 shown, the spiral groove 54 is located on the outer side surface of the first piston 2. Multiple upper vertical sections 52 and lower vertical sections 53 can be provided on the first piston 2, that is, a through hole can be provided on the end surface of the first piston 2 to connect with the spiral groove 54. The second piston 32 is provided with a second channel 33.

[0056] Example 2:

[0057] As Figure 8 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 the structural positions of other structures that need to provide damping force.

[0058] As Figure 8-11 shown, the first cylinder block 1 adopts a double-tube structure, including a first tube 14 and a second tube 15. The first chamber 10 is separated into a main chamber 11 and an auxiliary chamber 12 by a control section 50. The main chamber 11 is located inside the first tube 14, and the auxiliary 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 auxiliary chamber 12 are connected through the first channel 5. The control section 50 is located at the lower end of the first cylinder block 1, that is, the lower ends of the first tube 14 and the second tube 15. The first channel 5 is in a planar spiral structure, and a permanent magnet 4 is provided below the first channel 5. The permanent magnet 4 can move radially. An electromagnetic coil 16 is provided above the first channel 5. When the current of the electromagnetic coil 16 changes, the magnetic field strength also changes, thereby adjusting the damping force of the magnetorheological fluid. Of course, usually, the permanent magnet 4 is used to increase the damping force. However, when it is necessary to further increase the damping force, the magnetic field strength can be enhanced by applying a positive current. When it is necessary to reduce the damping force, a reverse current is applied to reduce the magnetic field strength. When the permanent magnet 4 moves radially to the outside, only the electromagnetic coil 16 is used to control the damping force, and the current magnitude can be adjusted.

[0059] The permanent magnet 4 is provided with a positioning through hole 46. An installation disk 17 is provided below the first cylinder block 1. The installation disk 17 is provided with a moving groove 18 and an insertion groove 19. The permanent magnet 4 is installed in the moving groove 18. The radial movement of the permanent magnet 4 realizes the switching from the second position to the first position. A first piston 2 is provided in the main chamber 11. The first piston 2 is provided with a first connecting rod 3. The first connecting rod 3 is directly or indirectly fixed to a first sleeve 34. A guiding strip 35 is provided at the lower end of the first sleeve 34. A plurality of guiding strips 35 are circumferentially arranged outside the first sleeve 34. To avoid affecting the installation of the shock absorber, the guiding strips 35 are not provided in some orientations. Part of the guiding strip 35 is arranged in the insertion groove 19 and inserted into the positioning through hole 46. The guiding strip 35 extends axially and has different radial distances at some positions. In this way, the axial movement of the guiding strip 35 can cause the radial movement of the permanent magnet 4.

[0060] As Figure 9 and Figure 10 shown, to ensure that the permanent magnet 4 has a large moving space, the first position is set closer to the center relative to the second position. As Figure 9 shown, when the first piston 2 is in the initial position, the permanent magnet 4 is in the first position, and the guiding strip 35 is also in a higher position. As Figure 10As shown, the first piston 2 moves downward, and the guide bar 35 also moves downward by a certain distance. At this time, the permanent magnet 4 moves outward to the second position, the magnetic field intensity received by the first channel 5 decreases, and the damping force also decreases.

[0061] Embodiment 3:

[0062] As Figure 8-11 shown, a second cylinder block 6 is provided above the first cylinder block 1. When the second cylinder block 6 moves relative to the first connecting rod 3, it can drive the permanent magnet 4 to move. The second cylinder block 6 is provided with magnetorheological fluid, and 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 block 6 is provided with a second magnetic attraction part 63 and a third magnetic attraction part 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 part 63 can also be increased, so that it has better support performance. When the damping needs to be reduced, the second electromagnetic coil 66 is powered off. Under a smaller acting force, the second piston 32 can move relative to the second cylinder block 6, that is, the permanent magnet 4 can be moved to change the damping force of the first cylinder block 1. When the second piston 32 approaches the third magnetic attraction part 64, the second electromagnetic coil 66 can be energized, so that it can be adsorbed on the third magnetic attraction part 64, and there is a larger damping force in the second cylinder block 6 to prevent the permanent magnet 4 from moving from the second position to the first position.

[0063] Embodiment 4:

[0064] As Figure 12 shown, a second cylinder block 6 is provided above the first cylinder block 1. When the second cylinder block 6 moves relative to the first connecting rod 3, it can drive the permanent magnet 4 to move. The second cylinder block 6 is provided with hydraulic oil, and 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 suction force. The second cylinder block 6 is provided with a second magnetic attraction part 63 and a third magnetic attraction part 64. The second magnetic attraction part 63 and the third magnetic attraction part 64 are magnets. By energizing the second electromagnetic coil 66 forward and backward, the position of the second piston 32 can be adjusted. For example, when energized forward, it can be adsorbed on the second magnetic attraction part 63, and when energized backward, it can be adsorbed on the third magnetic attraction part 64. In this way, the position of the permanent magnet 4 can be adjusted through the electromagnet structure. Of course, when the shock absorber expands and contracts rapidly, even if the second electromagnetic coil 66 is energized, due to the large acting force, the second piston 32 will separate from the second magnetic attraction part 63. In this way, there will be better comfort during the actual use of the vehicle, that is, when encountering a bumpy road surface, the damping force can be adjusted relatively quickly to make the vehicle body more stable.

[0065] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In the description of this application, "a plurality" means two or more unless otherwise specifically defined. For the shock absorber, it can usually also be used when it is inverted up and down or placed horizontally. Therefore, the up and down and other orientations are relative orientations rather than the actual used orientations. In each embodiment, the up and down of the drawing is used as the relative orientation for introduction.

[0066] As described above, the above is only the specific implementation manner of this application, but the protection scope of this application is not limited thereto. Any person skilled in the art within the technical scope disclosed by this application can easily think of changes or substitutions, which should all be covered within the protection scope of this application. Therefore, the protection scope of this application should be subject to 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 near 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 in the first position than when it is in 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. The permanent magnet (4) is fixed below the second cylinder (6) and moves with the second cylinder (6). The first connecting rod (3) is provided with a second piston (32), and the second cylinder (6) is provided with a second chamber (62). The second piston (32) is located in the second chamber (62). The second chamber (62) The second piston (32) 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, and the second piston (32) is provided with a second channel (33), and the second channel (33) is connected to the upper and lower sides of the second piston (32), and 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).

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: A shielding ring (22) is provided at the lower end of the first piston (2).

7. The magnetorheological damper according to claim 6, characterized in that: The second piston (32) is provided with a second electromagnetic coil (66).

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