Magnetorheological elastomer bushing for automobile suspension and automobile suspension system

Abstract

The invention relates to the technical field of elastic bushings, in particular to a magneto-rheological elastomer bushing for an automobile suspension and a vehicle suspension system. The magneto-rheological elastomer bushing comprises an inner sleeve and an outer sleeve which are coaxially arranged; the magnetorheological elastomer layer is filled between the inner sleeve and the outer sleeve, and the magnetorheological elastomer layer serves as a main bearing and rigidity adjusting component; the magnet exciting coil is arranged on the inner sleeve or the outer sleeve, and the magnet exciting coil applies a magnetic field to the magnetorheological elastomer layer to adjust the radial rigidity of the magnetorheological elastomer layer; the magneto-rheological elastomer composite material further comprises at least one magnetic conductive reinforcing piece which is arranged in the magneto-rheological elastomer layer in the radial direction, and the magneto-rheological elastomer layer is divided into at least two sub-layers in the radial direction by the magnetic conductive reinforcing piece. The rigidity of the vehicle can be instantly improved to enhance the control stability when high supporting performance is needed, the rigidity can be instantly reduced to optimize the riding comfort when high vibration filtering performance (such as a bumpy road surface) is needed, and dynamic intelligent balance between the two is achieved.

Description

Technical Field

[0001] This application relates to the technical field of elastic bushings, and in particular to a magnetorheological elastomer bushing for automobile suspension and a vehicle suspension system. Background Technology

[0002] The automotive suspension system is a key component affecting a vehicle's ride comfort and handling stability. Among these components, the bushings connecting the suspension control arms to the body or subframe, as core elastic and damping elements, directly influence suspension performance through their mechanical properties—especially radial stiffness. An ideal control arm bushing should be able to dynamically adjust its stiffness in real time under different driving conditions: providing high stiffness for situations requiring high handling response, such as high-speed steering and emergency lane changes; and providing low stiffness for situations requiring good vibration damping, such as driving over bumpy or rough roads, thus achieving a dynamic balance between the inherent contradiction of handling and comfort.

[0003] Currently, the mainstream automotive suspension control arm bushings are mainly passive designs, commonly including rubber bushings and hydraulic bushings: rubber bushings rely entirely on the rubber material formulation, vulcanization process, and structural geometry to determine their static and dynamic stiffness, and their performance is fixed once manufactured; hydraulic bushings have a liquid chamber and damping channel designed inside the rubber main spring, which can provide better damping characteristics at specific frequencies (such as the engine idling vibration frequency) to improve comfort, but their effective stiffness adjustment range is still very limited, and their structure is complex, with potential leakage risks and maintenance problems.

[0004] Whether it is a rubber bushing or a hydraulic bushing, they are essentially passive components that cannot actively adjust their stiffness according to real-time changes in driving conditions and driver intentions. This means that vehicle chassis performance must be compromised between prioritizing handling and prioritizing comfort during the design phase, making it impossible to simultaneously meet users' increasingly diverse and intelligent demands for vehicle dynamic performance. Summary of the Invention

[0005] The purpose of this invention is to provide a magnetorheological elastomer bushing for automotive suspension and a vehicle suspension system, to solve the technical problems of traditional passive bushings having non-adjustable stiffness and being unable to simultaneously ensure vehicle handling stability and ride comfort. This bushing can continuously adjust its stiffness in real time via electronic control signals, thereby quickly adapting to the needs of different driving conditions.

[0006] Firstly, to solve the above-mentioned technical problems, the present invention adopts the following technical solution: A magnetorheological elastomer bushing for automotive suspension, comprising: Coaxial inner and outer sleeves; A magnetorheological elastomer layer is filled between the inner sleeve and the outer sleeve, and the magnetorheological elastomer layer serves as the main load-bearing and stiffness adjustment component; An excitation coil is disposed between the inner sleeve and the outer sleeve. The excitation coil adjusts the radial stiffness of the magnetorheological elastomer layer by applying a magnetic field to the magnetorheological elastomer layer. It also includes at least one magnetically conductive reinforcing member radially disposed within the magnetorheological elastomer layer, dividing the magnetorheological elastomer layer radially into at least two sub-layers.

[0007] By adopting the above technical solution, when the vehicle is under different driving conditions (such as smooth cruising or sharp cornering), the controller inputs currents of different magnitudes to the excitation coil. The current generates a magnetic field around the coil, which acts on the magnetorheological elastomer layer, changing the ordered arrangement of its internal magnetic particles, thereby causing an instantaneous change in the shear modulus of the elastomer. Ultimately, this change manifests as an active, real-time adjustment of the overall radial stiffness of the bushing; it solves the fundamental defect of traditional passive bushings (rubber bushings or hydraulic bushings) that cannot respond to dynamic changes once the stiffness is fixed, as mentioned in the background technology, making vehicle operation more stable and improving ride comfort; it can satisfy both handling and comfort, meeting users' increasingly diversified and intelligent demands for vehicle dynamic performance; the magnetic reinforcement component can guide and concentrate the magnetic lines of force generated by the excitation coil, allowing more magnetic flux to pass through the working area (magnetorheological elastomer layer), thereby improving the utilization rate of the magnetic field; this can achieve the same current strength Obtaining a stronger effective magnetic field at a lower temperature, or reducing the current required to achieve the same magnetic field strength, helps improve the system's energy efficiency and control sensitivity. The magnetic reinforcement not only plays a magnetic guiding role but also acts as a built-in mechanical skeleton. In the static or low-current state without power, the magnetic reinforcement, as a physical support structure, can significantly improve the basic structural stiffness and deformation resistance of the bushing. In the energized state, this structure can effectively guide and redistribute the magnetic field, making it act more evenly on the separated elastic sublayers. This provides a structural basis for simultaneously improving the static mechanical properties and dynamic electromagnetic control efficiency of the bushing.

[0008] Optionally, the magnetically conductive reinforcing member is a silicon steel sheet embedded in the magnetorheological elastomer layer.

[0009] By adopting the above technical solution, silicon steel sheets are embedded in the magnetorheological elastomer layer as a laminated structure, and their high magnetic permeability is utilized under the action of a magnetic field. As a mature soft magnetic material, silicon steel sheets have high magnetic permeability and low hysteresis loss, which can conduct magnetic lines of force more efficiently, thus enhancing the magnetic field converging effect more effectively than using other magnetic materials (such as ordinary low-carbon steel). The introduction of silicon steel sheets can itself serve as a structural reinforcement, slightly improving the basic structural stiffness of the bushing in the absence of a magnetic field (power off state). The axially extending silicon steel sheets form a complete and coherent magnetic guiding and support frame. In terms of magnetic circuit, it ensures that the magnetic field can form a uniform channel with low magnetic resistance along the axial direction, reducing the discontinuity and loss of magnetic flux during conduction and optimizing the uniformity of magnetic field distribution. In terms of structure, the continuous sheet structure provides a larger support area and a more coherent force transmission path, further enhancing the structural support and reinforcement effect, and enabling the bushing to exhibit better stability and durability when subjected to complex loads.

[0010] Optionally, at least two sets of the magnetorheological elastomer layers are uniformly arranged along the axial direction of the inner sleeve.

[0011] By adopting the above technical solution, the functionality and reliability of the bushing are improved through modular design. From a mechanical perspective, the multiple sets of designs can distribute the load, improve stress distribution, and allow for more complex stiffness characteristics by configuring elastomer layers with different formulations. From an electromagnetic and control perspective, multiple independent magnetorheological elastomer working regions provide a physical basis for implementing zonal and segmented control, which is conducive to realizing more precise stiffness adjustment strategies. This design can more effectively guide the magnetic field to both the upper and lower elastomer layers simultaneously, maximizing the utilization of the magnetic field generated by the coil and further enhancing the uniformity of magnetic field and stiffness changes. It also reduces the imbalance phenomenon that may occur when the coil bias causes a strong magnetic field at one end and a weak magnetic field at the other end.

[0012] Optionally, a rubber layer is filled between the magnetorheological elastomer layers.

[0013] By adopting the above technical solution, the rubber layer, as a passive elastic element, can provide deterministic, magnetic field-independent buffering and damping, which helps filter vibrations in specific frequency bands. Simultaneously, it mechanically decouples and isolates the actively controlled magnetorheological elastomer layer to a certain extent, reducing interlayer electromagnetic and mechanical interference. In extreme cases (such as circuit failures), the rubber layer ensures that the bushing retains its basic elastic function, improving system reliability; and the added filler rubber layer can protect the internal structure under shear stress, reducing internal structural damage.

[0014] Optionally, it also includes a magnetic shielding ring, which is connected to the outer sleeve or inner sleeve to constrain the magnetic field path.

[0015] By adopting the above technical solution, the main technical effect of the magnetic isolation ring is to constrain the magnetic field path to improve the magnetic circuit efficiency. Specifically, as a component with high magnetic resistance, the magnetic isolation ring can block or reduce the leakage of magnetic lines of force from areas outside the preset magnetic circuit (the path expected to pass through the magnetorheological elastomer layer), especially the leakage magnetic field at both ends of the axis. This forces more magnetic lines of force to concentrate through the magnetorheological elastomer working layer, reducing the waste of magnetomotive force, thereby enhancing the magnetic field strength in the working area under the same current, improving the utilization efficiency of electromagnetic energy and the accuracy of magnetic field control.

[0016] Optionally, a limiting block is provided on the side of the outer sleeve near the inner sleeve corresponding to the magnetorheological elastic layer, and a limiting groove is formed on the outer sleeve corresponding to the limiting block.

[0017] By adopting the above technical solution, a mechanical limiting structure consisting of a limiting block on the outer sleeve and an upper limiting groove on the inner sleeve is introduced to constrain the shear deformation of the magnetorheological elastomer layer under extreme loads, preventing structural damage or failure caused by excessive deformation. This enhances the durability and overload protection capability of the bushing, ensuring that the core functional components operate within a safe working range.

[0018] Optionally, the excitation coil is arranged around the outside of the inner sleeve.

[0019] By adopting the above technical solution, a tight coupling between the magnetic field and the working layer of the elastomer is achieved. Placing the coil directly outside the inner sleeve and closely adjacent to the magnetorheological elastomer layer can minimize the loss of the magnetic field in the air before reaching the elastomer. This compact layout ensures that magnetic energy can be efficiently and directly transferred to the magnetorheological elastomer layer to be regulated, which is a key structural guarantee for achieving rapid and efficient stiffness adjustment.

[0020] Optionally, several excitation coils are provided and correspondingly disposed between two adjacent magnetorheological elastomer layers.

[0021] By adopting the above technical solution, independent control of the magnetic field is achieved in different zones. Each coil can independently adjust the magnetic field strength of its corresponding region, thereby allowing for differentiated adjustment of the stiffness of the bushing at different axial positions. This enables the bushing to adapt to more complex asymmetric load conditions, achieve multi-dimensional dynamic performance optimization, and improve the freedom and precision of control; moreover, multiple coils can increase the magnetic force to meet different stiffness variation adjustment requirements.

[0022] Optionally, the inner sleeve is provided with an annular mounting groove, and the excitation coil is partially or entirely placed in the annular mounting groove.

[0023] By adopting the above technical solution, the mounting groove provides precise positioning and reliable mechanical fixation for the coil, preventing it from shifting or loosening under vibration conditions, thus improving the structural reliability and durability of the bushing. Embedding the coil part into the groove helps to reduce the overall radial dimension of the bushing, making the structure more compact. The increased contact area between the coil and the metal inner sleeve facilitates the more effective conduction and dissipation of heat generated during coil operation through the inner sleeve, thereby improving thermal management. Furthermore, the annular mounting groove can reduce the damage to the coil caused by external forces.

[0024] Secondly, the vehicle suspension system provided in this application adopts the following technical solution: A vehicle suspension system includes a magnetorheological elastomer bushing.

[0025] By adopting the above technical solutions, the overall dynamic performance of the vehicle suspension system is intelligently improved. By integrating the adjustable stiffness bushing into the suspension and cooperating with vehicle sensors (such as vehicle speed, steering angle, and acceleration sensors) and controllers, the suspension system can actively adjust the stiffness of the connection points according to real-time road conditions and driving intentions. This achieves a dynamic and intelligent balance and optimization between the two traditionally contradictory performance indicators of vehicle handling stability and ride comfort.

[0026] In summary, this application includes at least one of the following beneficial technical effects: 1. The stiffness of traditional rubber or hydraulic bushings is fixed after manufacturing and cannot respond to dynamically changing driving conditions. This invention adjusts the current of the excitation coil through an electronic control signal, directly changing the magnetic field strength acting on the magnetorheological elastomer layer, thereby causing continuous and reversible changes in its shear modulus and the overall radial stiffness of the bushing within milliseconds. This allows the vehicle to instantly increase stiffness to enhance handling stability when high support is required (such as steering and lane changing), and instantly decrease stiffness to optimize ride comfort when high vibration damping is required (such as on bumpy roads), achieving a dynamic and intelligent balance between the two. 2. This invention directly integrates the excitation coil that generates the regulating magnetic field onto the sleeve (inner or outer sleeve), and simultaneously optimizes the magnetic circuit and enhances the foundation stiffness by embedding a magnetically conductive reinforcing component (such as a silicon steel sheet) within the magnetorheological elastomer layer. This design highly integrates the functions of "signal input - magnetic field generation - stiffness change" into a compact mechanical component, eliminating the need for complex external hydraulic or large-displacement mechanical actuation mechanisms. The magnetic field adjustment has almost no inertia, resulting in an extremely fast system response speed and a reliable structure, making it easy to directly replace and install in existing suspension layouts. 3. By using a sleeve made of magnetically conductive material to form a low magnetic reluctance main magnetic circuit, embedding high magnetic permeability reinforcing components (such as silicon steel sheets) in the elastic layer to converge and uniformly distribute the magnetic field, and optionally setting a magnetic isolation ring at the end to constrain magnetic field leakage, a highly efficient and controllable closed or semi-closed magnetic circuit is constructed. This design minimizes the waste of magnetomotive force, enabling the limited input electrical energy to be more efficiently converted into a working magnetic field acting on the smart material. This reduces energy consumption while expanding the effective adjustment range of bushing stiffness and improving the linearity and control accuracy between stiffness changes and current input. Attached Figure Description

[0027] Figure 1 This is a diagram illustrating the internal structure of the magnetorheological elastomer bushing in Embodiment 1 of this application; Figure 2 This is a cross-sectional view of the magnetorheological elastomer bushing in Embodiment 1 of this application; Figure 3 This is a diagram illustrating the internal structure of the magnetorheological elastomer bushing in Embodiment 2 of this application; Figure 4 This is a cross-sectional view of the magnetorheological elastomer bushing in Embodiment 2 of this application.

[0028] Reference numerals: 1. Inner sleeve; 2. First inner layer magnetorheological elastomer; 3. First silicon steel sheet; 4. First outer layer magnetorheological elastomer; 5. First excitation coil; 6. First filling rubber layer; 7. Second inner layer magnetorheological elastomer; 8. Second silicon steel sheet; 9. Second outer layer magnetorheological elastomer; 10. Outer sleeve; 11. Second filling rubber layer; 12. Third outer layer magnetorheological elastomer; 13. Third silicon steel sheet; 14. Third inner layer magnetorheological elastomer; 15. Second excitation coil; 16. Lower coil magnetic field closed loop; 17. Upper coil magnetic field closed loop; 18. Single-layer coil magnetic field closed loop. Detailed Implementation

[0029] The following combination Figures 1 to 4 This application will be described in further detail.

[0030] This embodiment discloses a magnetorheological elastomer bushing for automotive suspension.

[0031] Example 1: Refer to Figure 1 and Figure 2The magnetorheological elastomer bushing has an overall cylindrical sleeve structure. Its core functionality lies in utilizing the field-induced modulus characteristics of the magnetorheological elastomer material to achieve real-time, continuous adjustment of radial stiffness via an electrically controlled magnetic field. The bushing's main frame consists of a coaxially arranged inner metal sleeve 1 and an outer sleeve 10, with an annular cavity between them filled with a magnetorheological elastomer layer, serving as the core intelligent material. An excitation coil for generating the controllable magnetic field can be selectively mounted on either the inner sleeve 1 or the outer sleeve 10, depending on the magnetic circuit design requirements. Furthermore, a magnetically conductive reinforcing element is embedded within the magnetorheological elastomer layer to guide the magnetic field and enhance the base stiffness. By adjusting the current in the excitation coil through the control system, the magnetic field strength acting on the magnetorheological elastomer layer can be changed, thereby achieving intelligent switching of the overall bushing stiffness from soft to hard.

[0032] The specific structure, mutual position and connection relationship of each component of this bushing are described in detail below.

[0033] The inner sleeve 1 is a cylindrical metal part, typically used as a connection to the suspension control arm; its outer surface is coaxially fitted with a cylindrical outer sleeve 10, which is connected to the vehicle body or subframe; the inner sleeve 1 and the outer sleeve 10 together constitute the mechanical body of the bushing and an important component of the magnetic circuit; to form an efficient low magnetic reluctance magnetic circuit, this embodiment preferably uses a metal material with good magnetic permeability (such as low carbon steel) to manufacture at least one of the inner sleeve 1 and the outer sleeve 10. When the inner sleeve 1 is made of a magnetically permeable material, it can also serve as the magnetic core of the excitation coil; when the outer sleeve 10 is made of a magnetically permeable material, it can mainly serve as the return path of the magnetic circuit formed by the yoke.

[0034] In other embodiments, the excitation coil can be placed on the inner wall of the outer sleeve 10 as a magnetic core; the sleeve is made of a magnetically conductive material, forming a low magnetic reluctance magnetic circuit channel; the inner sleeve 1 (if made of a magnetically conductive material) can become part of the coil core, and the outer sleeve 10 can serve as a magnetic yoke; this design can provide a complete, closed or semi-closed low magnetic reluctance loop for the magnetic flux generated by the excitation coil, allowing the magnetic lines of force to pass smoothly through the magnetorheological elastomer layer to form a loop; this significantly reduces the total magnetomotive force (i.e., ampere-turns) required to establish an effective working magnetic field and improves the magnetic circuit efficiency of the entire system.

[0035] The excitation coil is the active component that generates the regulating magnetic field. Its installation position is flexible. The core design principle is that the magnetic field it generates can effectively act on the magnetorheological elastomer layer between the inner sleeve 1 and the outer sleeve 10.

[0036] In a preferred embodiment, the excitation coil, serving as the first excitation coil 5, is mounted on the inner sleeve 1. Specifically, an annular mounting groove can be formed on the outer circumferential surface of the inner sleeve 1, and the coil can be tightly wound or fully embedded in the annular mounting groove; in this embodiment, full embedding is preferred. This embedded mounting provides a compact structure, reliable fixation, and allows the magnetic field generated by the coil to be directly and efficiently coupled to the magnetorheological elastomer layer through the magnetically conductive inner sleeve 1, which is beneficial for achieving rapid response. The coil leads are led out through pre-set channels and connected to the controller.

[0037] In another feasible implementation, the excitation coil can also be installed on the inner surface of the outer sleeve 10. For example, an annular groove can be formed in the inner wall of the outer sleeve 10 to house the coil. In this case, if the outer sleeve 10 is made of a magnetically conductive material, the magnetic field generated by the coil can be guided through the outer sleeve 10 and penetrate the magnetorheological elastomer layer radially inward. Regardless of whether the coil is installed in the inner sleeve 1 or the outer sleeve 10, the purpose is to establish a sufficiently strong and controllable radial magnetic field in the region where the magnetorheological elastomer layer is located.

[0038] The cross-section of the annular groove can be set to be a square larger than that of the excitation coil, or it can be a rectangle, trapezoid, arc, or other shapes. In this embodiment, it is preferably rectangular, gradually increasing in the direction away from the axis of the inner sleeve 1.

[0039] Magnetorheological elastomer (MRE) layers are comparable to traditional rubber bushings in terms of space-filling form. Magnetorheological elastomers are a type of smart composite material whose main components include a polymer matrix (such as silicone rubber), magnetic particles (such as carbonyl iron powder), and coupling agents that improve interfacial bonding. Their shear modulus can change significantly, rapidly, and reversibly with the application and removal of an external magnetic field. By applying a magnetic field during the material curing process, the particles can be oriented to form a chain-like structure, which is the key to giving it a smart response.

[0040] Specifically, multiple sets of magnetorheological elastomer layers are provided. In this embodiment, two sets are preferred. The two sets of magnetorheological elastomer layers are arranged symmetrically along the axial direction of the inner sleeve 1. That is, on the upper and lower sides corresponding to the axial position of the excitation coil, magnetorheological elastomers with basically the same geometric shape and volume are filled respectively, namely the first layer of magnetorheological elastomer and the second layer of magnetorheological elastomer. This symmetrical design not only makes the stress distribution of the bushing more balanced when it is subjected to radial load, improving the structural reliability, but also lays the geometric foundation for establishing a uniform magnetic field distribution in the upper and lower working areas, thereby ensuring the linearity and controllability of stiffness adjustment.

[0041] When the coil is not energized, the magnetorheological elastomer exhibits basic elasticity and is responsible for initial vibration isolation.

[0042] The complete magnetic field channel is formed by all magnetically conductive components such as the inner sleeve 1, silicon steel sheet, and outer sleeve 10. When the excitation coil is energized, a magnetic field is generated and a magnetic flow path is formed according to the closed loop 18 of the single-layer coil magnetic field.

[0043] The magnetic reinforcement component optimizes the uniformity of the magnetic field distribution in the working area (magnetorheological elastomer layer) and improves the basic structural stiffness under zero-field or weak-field conditions. The magnetic reinforcement component is mainly made of metal materials with high magnetic permeability, such as iron-nickel alloys (permalloy) with better magnetic permeability and loss characteristics, iron-silicon-aluminum alloys or amorphous nanocrystalline alloys with good high-frequency characteristics, or soft magnetic ferrites and other soft magnetic composite materials (SMC) suitable for suppressing eddy currents at high frequencies. Its function is analogous to silicon steel sheets in transformer cores, used for efficient conduction and convergence of magnetic lines of force. In this embodiment, laminated silicon steel sheets are preferably used as magnetic reinforcement components, and the magnetic reinforcement component is bonded or vulcanized with the magnetorheological elastomer to form a stable connection.

[0044] These silicon steel sheets are sheet-like, extending axially along the inner sleeve 1 and arranged continuously and uniformly in the circumferential direction, thereby dividing the magnetorheological elastomer layer radially into multiple alternating elastomer sub-layers and magnetically conductive sheet layers; in other embodiments, the silicon steel sheets are annular structures; in this embodiment, a layer of silicon steel sheets is provided, namely a first silicon steel sheet 3 and a second silicon steel sheet 8. The first silicon steel sheet 3 divides the first layer of magnetorheological elastomer into a first inner layer magnetorheological elastomer 2 and a first outer layer magnetorheological elastomer 4; the second silicon steel sheet 8 divides the second magnetorheological elastomer into a second inner layer magnetorheological elastomer 7 and a second outer layer magnetorheological elastomer 9. For example, a set of such silicon steel sheets can be set in each symmetrical magnetorheological elastomer region. The high permeability of the silicon steel sheets can effectively guide and concentrate the magnetic flux generated by the excitation coil through each elastomer sublayer, significantly improving the utilization efficiency of the magnetic field. This results in a greater effective field strength and a wider range of stiffness variation for the magnetorheological elastomer under the same current excitation. At the same time, these silicon steel sheets embedded in the elastomer also constitute an internal reinforcing skeleton, significantly enhancing the static structural stiffness and load-bearing capacity of the bushing in the unenergized state.

[0045] To further improve magnetic circuit efficiency and reduce magnetic flux leakage outside the working path, this bushing optionally includes a magnetic isolation ring; the magnetic isolation ring is made of a material with high magnetic reluctance (such as aluminum, austenitic stainless steel, or certain non-magnetic alloys). Its typical installation location is at the axial end of the outer sleeve 10, specifically on the upper and / or lower end face of the outer sleeve 10. When the excitation coil is installed in the inner sleeve 1, the magnetic isolation ring primarily prevents axial leakage of the magnetic field from the upper and lower end faces. When the coil is installed in the outer sleeve 10, the magnetic isolation ring also confines the magnetic field, making it more concentrated radially through the elastomer layer. The magnetic isolation ring forces the magnetic lines of force to form a loop mainly along a preset effective path (the radial path through the magnetorheological elastomer layer), thereby concentrating the magnetomotive force to drive the modulus change of the smart material, improving the overall energy efficiency and control accuracy of the system.

[0046] Furthermore, in order to reduce the external shear force received by the excitation coil during operation, a first filling rubber layer 6 is provided between two adjacent sets of magnetorheological elastomer layers, and the filling rubber layer abuts against the excitation coil or has a gap.

[0047] The working process and overall technical effects of the magnetorheological elastomer bushing in this embodiment are as follows: During vehicle operation, the electronic control unit receives signals from vehicle sensors in real time (such as vehicle speed, steering angle, lateral acceleration, and vertical acceleration) and determines the suspension bushing stiffness requirements based on preset control strategies. When the system determines that high handling is required (e.g., high-speed cornering, emergency lane changes), the control unit outputs a large current to the excitation coil. The current generates a strong magnetic field in the coil, which is efficiently converged and guided by the magnetically conductive sleeve (inner sleeve 1 or outer sleeve 10) and silicon steel sheets, uniformly penetrating the symmetrically arranged magnetorheological elastomer layers radially. The magnetic isolation ring effectively suppresses end leakage of the magnetic field. Under the action of the strong magnetic field, the magnetic particles inside the magnetorheological elastomer rapidly align into a chain structure along the direction of the magnetic field lines, causing the macroscopic shear modulus of the material to rise sharply within milliseconds, resulting in a significant increase in the overall radial stiffness of the bushing. At this time, the bushing becomes stiff, providing strong lateral support for the suspension control arms, greatly improving the vehicle's steering accuracy, body roll suppression capability, and overall handling stability.

[0048] Conversely, when the vehicle is traveling on uneven roads, over speed bumps, or when the system prioritizes ride comfort (e.g., during cruising or on bumpy roads), the control unit reduces or completely cuts off the current to the excitation coil. As the magnetic field weakens or disappears, the chain-like structure of magnetic particles inside the magnetorheological elastic body disintegrates, returning to a disordered state, and the material's shear modulus decreases rapidly. The overall radial stiffness of the bushing decreases accordingly, exhibiting a softer characteristic, effectively isolating and absorbing vibration and impact energy transmitted from the tires to the vehicle body, significantly improving ride smoothness and comfort.

[0049] In summary, the magnetorheological elastomer bushing for the automotive suspension control arm provided by this invention constructs a compact, efficient, and rapidly responsive intelligent stiffness adjustment mechanism by flexibly placing the excitation coil within the inner sleeve 1 or outer sleeve 10, using a symmetrically arranged magnetorheological elastomer layer with embedded high permeability reinforcement as the intelligent working medium, and optionally equipping it with an end magnetic isolation ring to optimize the magnetic circuit. This bushing achieves a wide range of rapid and reversible stiffness adjustments solely through electrical signals, fundamentally overcoming the limitations of fixed performance in traditional passive bushings. It enables the suspension system to intelligently adapt to complex and changing driving conditions, dynamically and precisely seeking the optimal balance between the inherent contradiction of handling stability and ride comfort, significantly improving the overall dynamic performance and adaptive capability of the vehicle.

[0050] Example 2: Refer to Figure 3 and Figure 4 The difference between this example and Embodiment 1 is that, based on Embodiment 1, multiple independent excitation coils can be set. As a preferred embodiment, two excitation coils are set, that is, a second excitation coil 15 is added as the lower coil, and the first excitation coil 5 is used as the upper coil. Correspondingly, three sets of magnetorheological elastomer layers are selected, and the two excitation coils are set at intervals relative to the three sets of magnetorheological elastomer layers, that is, a third magnetorheological elastomer is added. A third silicon steel sheet 13 is set in the third magnetorheological elastomer to form a third outer magnetorheological elastomer 12 and a third inner magnetorheological elastomer 14. A second filling rubber layer 11 is set between the second and third magnetorheological elastomers, and the filling rubber layer abuts against the excitation coil or has a gap. Each coil can be controlled independently or uniformly, so that the stiffness of the upper and lower parts of the bushing can be adjusted differently to cope with asymmetric loads.

[0051] Furthermore, to improve durability, an inwardly protruding annular limiting block (not shown in the figure) is provided on the inner wall of the outer sleeve 10 near the end of each group of magnetorheological elastomer layers; correspondingly, an annular limiting groove is formed on the outer wall of the inner sleeve 1 at the corresponding position. The clearance fit between the limiting block and the limiting groove can limit the maximum shear displacement of the elastomer layer under extreme working conditions, protecting it from excessive deformation and damage.

[0052] In this embodiment, when the first excitation coil 5 and the second excitation coil 15 are energized, the magnetic field forms a complete magnetic flow path according to the closed loop 17 of the upper coil magnetic field and the closed loop 16 of the lower coil magnetic field. These two are not independent components, but refer to two relatively independent but possibly coupled magnetic flux paths formed by the magnetically conductive components (inner sleeve 1, each layer of silicon steel sheets, outer sleeve 10).

[0053] This embodiment sets up two independently controllable excitation coils and arranges three sets of magnetorheological elastomer layers at intervals with the coils, so that the bushing is divided into at least two independently or uniformly adjustable stiffness regions in the axial direction. This enables the vehicle control system to perform differentiated stiffness compensation according to the asymmetrical loads on the left and right wheels or the front and rear ends (such as cornering roll and braking pitch), thereby achieving more precise and proactive control of the vehicle attitude and more selective stiffness adjustment.

[0054] The rubber layer provides deterministic elasticity and damping independent of the electronic control system, helping to filter vibrations at specific frequencies. As a mechanical and electromagnetic buffer and isolation layer, the rubber layer can reduce mutual interference between adjacent active layers. In the event of circuit failure or coil failure, the rubber layer ensures that the bushing still retains its basic elastic support function, significantly improving the reliability of the system. It also protects the coil and serves as a seal, support, insulation, and auxiliary force transmission layer. It fills the non-functional gaps between the coil, magnetic circuit, and structural components to fix internal components, prevent dust and moisture intrusion (especially protecting the coil), provide additional elastic support, and help smoothly transfer the load from the inner sleeve 1 to the MRE layer and the outer sleeve 10.

[0055] The annular limiting block and limiting groove set at the corresponding positions of the outer sleeve 10 and the inner sleeve 1 constitute a rigid mechanical stop mechanism. Under extreme impact loads, this mechanism can directly limit the maximum relative displacement between the inner and outer sleeves 10, thereby constraining the shear deformation of the magnetorheological elastomer layer and the rubber layer within a safe range, effectively preventing tearing or permanent damage caused by excessive material deformation, and greatly enhancing the impact resistance and service life of the bushing.

[0056] Each excitation coil is positioned between two magnetorheological elastomer layers. This "sandwich" arrangement allows the magnetic field generated by the coil to be more concentratedly directed to the working areas of the adjacent upper and lower elastomer layers, reducing magnetic field leakage to the axial distal end. Independent coil control allows the application of magnetic fields of different intensities to the elastomer layers in specific areas, realizing the "localization" and "customization" of stiffness adjustment, and improving the targeting of magnetic energy utilization and overall energy efficiency.

[0057] The second silicon steel sheet 8 plays the role of guiding and bridging the central magnetic flux in the magnetic circuit structure. It connects the upper and lower magnetic circuits, effectively diverting and guiding the magnetic flux from the coil to the lower MRE region, ensuring that the magnetic field can uniformly and fully cover the two layers of smart materials, thereby forming a complete, low magnetic resistance closed magnetic circuit and maximizing the utilization rate of the magnetic field.

[0058] In summary, the technical solution of Example 2, through the synergistic design of multi-coil zone control, active / passive material composite, and mechanical limit protection, upgrades the bushing from an "overall adjustable" intelligent element into a high-performance, high-reliability suspension component with axial gradient adjustment capability, excellent shock resistance reliability, and functional safety redundancy. It is particularly suitable for advanced chassis systems with extreme requirements for handling, comfort, and reliability.

[0059] The core difference between single-stage and double-stage magnetorheological bushings lies in the number and layout of the magnetic field generators: a single-stage coil design contains only a single ring excitation coil located in the middle of the structure, generating a single overall magnetic field. Although it can cover the upper and lower layers of magnetorheological elastomers (MREs), it suffers from uneven magnetic field distribution, limited adjustable range, and the maximum field strength is limited by the length of the magnetic path and high magnetic reluctance, thus only achieving overall "hardening" or "softening". On the other hand, a double-stage coil design contains two independent coils, forming a dual magnetic circuit that can be independently controlled and coupled through the middle layer of silicon steel sheets. It not only shortens the magnetic path and reduces magnetic reluctance through partitioned excitation, making the magnetic field stronger and more concentrated—especially in the middle layer MRE region, magnetic flux superposition can be achieved, breaking through the field strength limit of a single coil—but also allows for independent control of the upper and lower parts of the bushing, adjustment of axial stiffness damping gradient, and multiple working modes (such as partitioned tuning, unidirectional reinforcement, or reverse adjustment) through independent adjustment of the dual coil current. This greatly expands the adjustable range, adaptability, and control precision of the bushing, enabling it to cope with complex vibration conditions more flexibly and efficiently.

[0060] This application also discloses a vehicle suspension system, including a magnetorheological elastomer bushing.

[0061] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A magnetorheological elastomer bushing for automotive suspension, characterized in that: include: The inner sleeve (1) and the outer sleeve (10) are coaxially arranged. A magnetorheological elastomer layer is filled between the inner sleeve (1) and the outer sleeve (10), and the magnetorheological elastomer layer serves as the main load-bearing and stiffness adjustment component; An excitation coil is disposed between the inner sleeve (1) or the outer sleeve (10). The excitation coil adjusts the radial stiffness of the magnetorheological elastomer layer by applying a magnetic field to the magnetorheological elastomer layer. It also includes at least one magnetically conductive reinforcing member radially disposed within the magnetorheological elastomer layer, dividing the magnetorheological elastomer layer radially into at least two sub-layers.

2. The magnetorheological elastomer bushing for automotive suspension according to claim 1, characterized in that: The magnetically conductive reinforcing component is a silicon steel sheet embedded in the magnetorheological elastomer layer.

3. The magnetorheological elastomer bushing for automotive suspension according to claim 1, characterized in that: At least two sets of the magnetorheological elastomer layers are uniformly arranged along the axial direction of the inner sleeve (1).

4. The magnetorheological elastomer bushing for automotive suspension according to claim 3, characterized in that: A rubber layer is filled between the magnetorheological elastomer layers.

5. The magnetorheological elastomer bushing for automotive suspension according to claim 1, characterized in that: It also includes a magnetic shielding ring, which is connected to the outer sleeve (10) or the inner sleeve (1) to constrain the magnetic field path.

6. The magnetorheological elastomer bushing for automotive suspension according to claim 1, characterized in that: A limiting block is provided on the side of the outer sleeve (10) near the inner sleeve (1) corresponding to the magnetorheological elastic layer, and a limiting groove is opened on the outer sleeve (10) corresponding to the limiting block.

7. The magnetorheological elastomer bushing for automotive suspension according to any one of claims 1-6, characterized in that: The excitation coil is arranged around the outside of the inner sleeve (1).

8. The magnetorheological elastomer bushing for automotive suspension according to claim 7, characterized in that: Several excitation coils are provided and are correspondingly arranged between two adjacent magnetorheological elastomer layers.

9. The magnetorheological elastomer bushing for automotive suspension according to claim 8, characterized in that: The inner sleeve (1) has an annular mounting groove, and the excitation coil is partially or completely placed in the annular mounting groove.

10. A vehicle suspension system, characterized in that: Includes the magnetorheological elastomer bushing as described in any one of claims 1-9.

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