Magnetorheological elastomer shock absorber and preparation method thereof

Abstract

The invention belongs to the technical field of shock absorbers, and provides a magneto-rheological elastomer shock absorber and a preparation method thereof.The magneto-rheological elastomer shock absorber comprises a shell internally provided with a mounting position; the electromagnets are oppositely arranged on the mounting positions; the adjusting mechanism is arranged between the electromagnets and used for adjusting the rigidity of the shock absorber, the adjusting mechanism comprises a plurality of magneto-rheological elastomers, magnetic conductive plates and permanent magnets, the magnetic conductive plates are arranged between every two adjacent magneto-rheological elastomers, and the magneto-rheological elastomers and the magnetic conductive plates are arranged on the permanent magnets in a stacked mode; the power supply module comprises a power supply and a wire, the power supply is arranged outside the shell, and the power supply is connected with the electromagnet through the wire; the magnitude of the output current is adjusted through the power module, the magnetic field generated by the electromagnet is adjusted, and the magnetization degree of the magnetorheological elastomer is changed, so that the rigidity of the magnetorheological elastomer is changed, rigidity adjustment of the shock absorber is achieved, and the shock absorption effect of the shock absorber is improved.

Description

Technical Field

[0001] The invention relates to the technical field of shock absorbers, and in particular to a magnetorheological elastomer shock absorber and a preparation method thereof. Background Art

[0002] Shock absorbers are devices used to suppress the vibration caused by the rebound of the spring after absorbing shock and the impact from the road surface. They are widely used in the automotive field. When passing through uneven roads, although the shock-absorbing spring can filter the vibration of the road surface, the spring itself will still have reciprocating motion, and the shock absorber is used to suppress this spring jump to improve the smoothness of the car's ride.

[0003] Existing shock absorbers cannot freely change the hardness and stiffness of the rubber while maintaining the existing shape, resulting in poor overall shock absorption effect of the shock absorber and being unsuitable for changing engineering environments. Summary of the invention

[0004] In view of the above shortcomings of the prior art, an object of the present invention is to provide a magnetorheological elastomer shock absorber and a preparation method thereof, so as to solve the problem of poor shock absorbing effect of the shock absorber in the prior art.

[0005] To achieve the above objectives and other related objectives, in a first aspect, the present invention provides a magnetorheological elastomer shock absorber, comprising:

[0006] A housing, wherein a mounting position is provided in the housing;

[0007] An electromagnet is relatively arranged on the installation position;

[0008] An adjusting mechanism is arranged between the electromagnets and is used to adjust the stiffness of the shock absorber. The adjusting mechanism comprises a magnetorheological elastomer, a magnetic conductive plate and a permanent magnet. A plurality of magnetorheological elastomers are provided, and the magnetic conductive plate is arranged between two adjacent magnetorheological elastomers. The magnetorheological elastomer and the magnetic conductive plate are stacked and arranged on the permanent magnet.

[0009] The power supply module comprises a power supply and a wire, wherein the power supply is arranged outside the shell, and the power supply is connected to the electromagnet through the wire.

[0010] Optionally, the magnetorheological elastomer includes a core layer portion and a surface layer portion, the surface layer portion covers the core layer portion, the core layer portion is filled with magnetorheological fluid and thermoplastic elastomer solution, and the surface layer portion is filled with thermoplastic elastomer solution.

[0011] Optionally, the thermoplastic elastomer solution includes one or more of styrene-ethylene-butylene-styrene block copolymer (SEBS) solution, thermoplastic polyurethane (TPU) solution, silicone rubber (SR) solution, natural rubber (NR) solution, and styrene-butadiene rubber (SBR) solution.

[0012] Optionally, the thermoplastic elastic solution of the surface layer also includes conductive particles, and the conductive particles are evenly distributed in the thermoplastic elastomer solution.

[0013] Optionally, the iron content in the magnetorheological fluid is 30-60wt%, the mass fraction of the thermoplastic elastic solution in the surface layer is 10-50%, and the mass fraction of the thermoplastic elastomer solution in the core layer is 20-40%.

[0014] Optionally, the electromagnet includes an iron core and a coil, and the coil is wound around the iron core and electrically connected to the wire.

[0015] Optionally, at least two electromagnets are provided, and the winding directions of the coils of the two electromagnets are opposite.

[0016] Optionally, the magnetorheological elastomer and the magnetic conductive plate are stacked to form a square structure.

[0017] Optionally, the shell has an opening, and a protective cover for closing the installation position is provided on the opening, and the protective cover is detachably connected to the shell.

[0018] In a second aspect, the present invention provides a method for preparing a magnetorheological elastomer shock absorber, comprising:

[0019] A thermoplastic elastomer solution and a magnetorheological fluid are prepared, and the magnetorheological fluid and a part of the thermoplastic elastomer solution are selected and mixed uniformly by mechanical stirring to obtain a mixed solution;

[0020] The mixed solution is filled into the core layer, and the remaining thermoplastic elastomer solution is filled into the surface layer, and the filled surface layer covers the core layer to obtain a magnetorheological elastomer;

[0021] A magnetic conductive plate is placed between two adjacent magnetorheological elastomers, a permanent magnet is placed below the lowest magnetorheological elastomer, and electromagnets are placed on the left and right sides of the magnetorheological elastomer and placed in a shell to obtain a magnetorheological elastomer shock absorber.

[0022] In a magnetorheological elastomer shock absorber provided by the present invention, a power module energizes the electromagnet, which generates a magnetic field. Under the action of the magnetic field, the magnetorheological elastomer of the adjustment mechanism is magnetized. The output current is adjusted by the power module, and the magnetic field generated by the electromagnet is adjusted. The magnetization degree of the magnetorheological elastomer changes, thereby changing the stiffness of the magnetorheological elastomer, realizing the stiffness adjustment of the shock absorber, and improving the shock absorption effect of the shock absorber. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1A schematic structural diagram of a magnetorheological elastomer shock absorber according to an exemplary embodiment of the present invention;

[0024] Figure 2 A cross-sectional view from a first perspective of a magnetorheological elastomer shock absorber according to an exemplary embodiment of the present invention;

[0025] Figure 3 A cross-sectional view from a second perspective of a magnetorheological elastomer shock absorber according to an exemplary embodiment of the present invention.

[0026] Part Number Description

[0027] 1-shell; 2-protective cover; 3-power supply; 4-conducting wire; 5-core layer; 6-surface layer; 7-magnetic plate; 8-permanent magnet; 9-electromagnet. DETAILED DESCRIPTION

[0028] The following is a description of the implementation of the present invention by means of specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0029] It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no substantial technical significance. Any modification of the structure, change of the proportional relationship or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the effects and purposes that can be achieved by the present invention. At the same time, the terms such as "front", "back", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the present invention. The change or adjustment of their relative relationship should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content.

[0030] See also Figures 1 to 3 The present invention exemplarily provides a magnetorheological elastomer shock absorber, comprising:

[0031] A housing 1, wherein a mounting position is provided in the housing 1;

[0032] The electromagnet 9 is relatively arranged at the installation position;

[0033] An adjusting mechanism is arranged between the electromagnets 9 and is used to adjust the stiffness of the shock absorber. The adjusting mechanism includes a magnetorheological elastomer, a magnetic conductive plate 7 and a permanent magnet 8. A plurality of magnetorheological elastomers are provided, and a magnetic conductive plate 7 is provided between two adjacent magnetorheological elastomers. The magnetorheological elastomer and the magnetic conductive plate 7 are stacked on the permanent magnet 8.

[0034] The power module includes a power source 3 and a wire 4 . The power source 3 is arranged outside the housing 1 , and the power source 3 is connected to the electromagnet 9 through the wire 4 .

[0035] In the magnetorheological elastomer shock absorber provided by the present invention, the power module energizes the electromagnet 9, and the electromagnet 9 generates a magnetic field after being energized. Under the action of the magnetic field, the magnetorheological elastomer of the adjustment mechanism is magnetized. The output current is adjusted by the power module, and the magnetic field generated by the electromagnet 9 is adjusted. The magnetization degree of the magnetorheological elastomer changes, thereby changing the stiffness of the magnetorheological elastomer, realizing the stiffness adjustment of the shock absorber, and improving the shock absorption effect of the shock absorber.

[0036] In some embodiments, the magnetorheological elastomer includes a core layer portion 5 and a surface layer portion 6, the surface layer portion 6 covers the core layer portion 5, the core layer portion 5 is filled with magnetorheological fluid and a thermoplastic elastomer solution, and the surface layer portion 6 is filled with a thermoplastic elastomer solution. Specifically, the thermoplastic elastomer solution includes one or more of styrene-ethylene-butylene-styrene block copolymer (SEBS) solution, thermoplastic polyurethane (TPU) solution, silicone rubber (SR) solution, natural rubber (NR) solution, and styrene-butadiene rubber (SBR) solution. The surface layer is filled with the thermoplastic elastomer solution so that the surface layer portion 6 has rubber elasticity and plastic thermoplasticity. The core layer portion 5 is placed in the surface layer portion 6, and the surface layer portion 6 can fit in contact with the core layer portion 5 and cover the core layer portion 5.

[0037] In the above embodiment, the magnetorheological fluid and the thermoplastic elastomer solution are mixed and filled to form the core layer 5, thereby realizing the encapsulation of the magnetorheological fluid in a very small space, which not only avoids the performance change after deposition, but also maintains a high magnetostrictive effect, thus overcoming the problem of easy sedimentation and poor stability of the magnetorheological fluid.

[0038] It is worth mentioning that the magnetic conductive plate 7 is used to conduct the magnetic field and can also shape the magnetorheological elastomer to form a square structure. When the electromagnet 9 is energized to generate a magnetic field, the magnetic field can penetrate multiple magnetorheological elastomers and the magnetic conductive plate 7 to achieve the simultaneous change of the stiffness of multiple magnetorheological elastomers. At the same time, multiple magnetorheological elastomers can increase the overall stiffness of the shock absorber. By arranging a permanent magnet 8 under the lowest magnetorheological elastomer, the permanent magnet 8 can achieve bidirectional adjustment of the magnetic field size, thereby increasing the range of stiffness adjustment and improving the stiffness adjustment ability of the shock absorber.

[0039] In another embodiment, the present invention further provides a method for preparing a magnetorheological elastomer shock absorber, comprising at least the following steps:

[0040] Step 1: preparing a thermoplastic elastomer solution and a magnetorheological fluid, selecting the magnetorheological fluid and part of the thermoplastic elastomer solution and mixing them uniformly by mechanical stirring to obtain a mixed solution;

[0041] Step 2: Filling the mixed solution into the core layer, and filling the remaining thermoplastic elastomer solution into the surface layer, and the filled surface layer covers the core layer to obtain a magnetorheological elastomer;

[0042] Step 3: Place a magnetic conductive plate between two adjacent magnetorheological elastomers, place a permanent magnet under the lowest magnetorheological elastomer, place electromagnets on the left and right sides of the magnetorheological elastomer and place them in the shell to obtain a magnetorheological elastomer shock absorber.

[0043] In another embodiment, the present invention further provides a method for preparing a thermoplastic elastomer solution, comprising at least the following steps:

[0044] Step 1: mixing thermoplastic elastomer particles with a solvent, accelerating the dissolution of the thermoplastic elastomer particles by heating and stirring to form a uniform solution;

[0045] Step 2: Adjust the solid content of the thermoplastic elastomer solution according to demand. The solid content will affect the performance of the thermoplastic elastomer solution.

[0046] Step 3: Add one or more of plasticizer, stabilizer and antioxidant to the thermoplastic elastomer solution and continue stirring for 30 minutes.

[0047] It can be understood that for step one, the thermoplastic elastomer particles can be one or more of styrene-ethylene-butylene-styrene block copolymer (SEBS), thermoplastic polyurethane (TPU), silicone rubber (SR), natural rubber (NR), and styrene-butadiene rubber (SBR), and the solvent is an aqueous solvent such as purified water. Preferably, the thermoplastic elastomer particles are SEBS, which does not contain unsaturated double bonds, has good stability and aging resistance, and can improve the performance of the mixed thermoplastic elastomer solution.

[0048] Specifically, before mixing, the thermoplastic elastomer particles need to be crushed to a particle size of less than 1 mm, which can increase the specific surface area to accelerate dissolution. At the same time, the solvent is preheated to 40-50°C and maintained in this temperature range to avoid excessive temperature causing the solvent to volatilize too quickly. The solvent is first added to the reactor and stirring is started. The speed of the reactor is 200-500rpm, and then the crushed thermoplastic elastomer particles are slowly added. The temperature in the reactor is controlled to 50-80°C and stirring is continued for 2-4 hours to form a uniform solution.

[0049] For step three, the plasticizer can improve the flexibility of the mixed solution, the stabilizer can slow down the reaction during the solution mixing process, maintain chemical balance, and reduce surface tension. The antioxidant can prevent the solution from thermal oxidation degradation to improve the solution performance. After stirring and mixing, use a 200-mesh filter to filter out undissolved impurities, and place the filtered thermoplastic elastomer solution in a vacuum box for vacuum degassing to eliminate bubbles. The air pressure in the vacuum box is -0.1MPa, and the vacuum degassing time is 10-20 minutes.

[0050] In this embodiment, the thermoplastic elastic solution of the surface part 6 also includes conductive particles, and the conductive particles are evenly distributed in the thermoplastic elastomer solution. By adding conductive particles to the thermoplastic elastic solution of the surface part 6, the electromagnetic shielding function of the surface part 6 is achieved, so that the shock absorber can be used in scenes such as ships and military vehicles, thereby improving the applicability of the shock absorber.

[0051] In the above embodiment, the iron content in the magnetorheological fluid is 30-60wt%, the mass fraction of the thermoplastic elastic solution in the surface part 6 is 10-50%, and the mass fraction of the thermoplastic elastomer solution in the core part 5 is 20-40%. Specifically, a thermoplastic elastomer solution and a magnetorheological fluid are configured, a part of the thermoplastic elastomer solution and the magnetorheological fluid are selected for mechanical stirring and mixing to obtain a mixed solution, the mixed solution is injected into the core part, and then conductive particles are added to the remaining thermoplastic elastomer and injected into the surface part. After the solutions in the surface part 6 and the core part 5 are solidified, the core part 5 is placed in the surface part 6, the core part 5 is limited and fixed in the surface part 6, and the surface part 6 covers the core part 5 to obtain a magnetorheological elastomer.

[0052] In another embodiment, the present invention further provides a method for preparing a magnetorheological fluid, comprising at least the following steps:

[0053] Step 1: Wash the magnetic particles with dilute hydrochloric acid to remove surface oxides, wash with deionized water until neutral, and dry for later use;

[0054] Step 2: Heat the carrier liquid to 80-100°C, stir and remove moisture;

[0055] Step 3: Mix the magnetic particles and the carrier liquid in proportion, add a surfactant, and stir at a low speed for 10-20 minutes;

[0056] Step 4: Process the stirred and mixed magnetorheological fluid through a high-speed shear emulsifier for 30-60 minutes, or use ultrasonic dispersion for 30 minutes;

[0057] Step 5: Add anti-settling agent and antioxidant, and continue stirring until uniform;

[0058] Step 6: Place the evenly stirred magnetorheological fluid in a vacuum box for degassing for 1-2 hours.

[0059] It should be noted that, in step 1, the magnetic particles are carbonyl iron powders, and the particle size thereof is 1-10 μm.

[0060] For step 2, the carrier liquid is a low-viscosity, high-boiling-point liquid such as silicone oil, mineral oil or synthetic oil (such as poly-α-olefin), and its viscosity is 10-100 mPa·s. By heating and stirring the carrier liquid, the moisture in the carrier liquid can be removed to avoid the generation of bubbles during subsequent mixing and stirring, which affects the performance of the magnetorheological fluid.

[0061] For step three, the magnetorheological fluid is formed by mixing magnetic particles and a carrier liquid, the mass fraction of the magnetic particles in the magnetorheological fluid is 30-60%, the surfactant is oleic acid or a silane coupling agent, which can prevent the magnetic particles from agglomerating during stirring, and the mass fraction of the surfactant is 1%-5%.

[0062] For step 4, the rotation speed of the high-speed shear emulsifier is 10000-20000 rpm, and the frequency of the ultrasonic dispersion treatment is 20-40 kHz.

[0063] For step five, the anti-settling agent is 2% or 5% of nano-SiO, and the antioxidant is benzotriazole, which can extend the service life of the magnetorheological fluid.

[0064] For step six, the air pressure in the vacuum box is -0.1 MPa. Placing the magnetorheological fluid in the vacuum box for degassing can eliminate bubbles and further improve the performance of the magnetorheological fluid.

[0065] In this embodiment, the electromagnet 9 includes an iron core and a coil, the coil is wound around the iron core and electrically connected to the wire 4. Through the cooperation between the electromagnet 9 and the permanent magnet 8, the bias magnetic field of the permanent magnet 8 is superimposed on the variable magnetic field of the electromagnet 9 to form a composite magnetic field. By adjusting the coil current direction of the electromagnet 9 through the power supply module 3, the dynamic range of the magnetic field strength can be increased, thereby improving the stiffness adjustment ability of the shock absorber.

[0066] In detail, at least two electromagnets 9 are provided, the coils of the two electromagnets 9 are wound in opposite directions and the current directions are the same, forming a closed magnetic field, reducing magnetic leakage, improving the utilization rate of the magnetic field, making the dynamic response of the shock absorber faster and more stable, and improving the shock absorption effect.

[0067] In some embodiments, the magnetorheological elastomer and the magnetic conductive plate 7 are stacked to form a square structure. Specifically, the magnetic conductive plate 7 is placed between two adjacent magnetorheological elastomers, the permanent magnet 8 is in close contact with the magnetorheological elastomer of the bottom layer, and the electromagnet 9 is a cylindrical structure. The electromagnet 9 is arranged on two opposite sides of the square structure and in close contact with the two sides of the square structure. At this time, the magnetic conductive plate 7, the permanent magnet 8, the electromagnet 9 and the magnetorheological elastomer form a whole, further improving the stability of the magnetic field.

[0068] In this embodiment, the power supply 3 is a 12V or 24V adjustable DC regulated power supply. The adjustable DC regulated power supply can adjust the output current, thereby adjusting the magnetic field generated by the electromagnet 9 after power is turned on. Under the action of the magnetic field, the magnetorheological fluid inside the magnetorheological elastomer is magnetized. According to the degree of magnetization, the stiffness of the magnetorheological elastomer is adjusted, thereby realizing the stiffness adjustment of the shock absorber.

[0069] In this embodiment, the shell 1 has an opening, and a protective cover 2 for closing the installation position is provided on the opening. The protective cover 2 is detachably connected to the shell 1. Specifically, an assembly opening and a limiting groove are provided on the shell 1 near the opening. The assembly opening and the limiting groove are respectively arranged on opposite sides of the shell 1. The limiting groove is arranged on the inner wall of one side of the shell 1, and the assembly opening is arranged on the other side of the shell 1 and passes through the shell. The protective cover 2 is horizontally inserted into the assembly opening. The protective cover 2 is inserted from the assembly opening and moves horizontally until it abuts against the limiting groove. The protective cover 2 is limited and fixed on the limiting groove to close the opening. A relatively closed space is formed by the shell 1 and the protective cover 2 to shield and protect the adjustment mechanism and the electromagnet 9 on the installation position to prevent harmful gases, dust and other impurities in the outside air from adhering to the adjustment mechanism and the electromagnet 9, causing the adjustment mechanism and the electromagnet 9 to be contaminated.

[0070] In summary, in the magnetorheological elastomer shock absorber and its preparation method provided by the present invention, the power module energizes the electromagnet 9, and the electromagnet 9 generates a magnetic field after being energized. Under the action of the magnetic field, the magnetorheological elastomer of the adjustment mechanism is magnetized. The output current is adjusted by the power module, and the magnetic field generated by the electromagnet 9 is adjusted. The magnetization degree of the magnetorheological elastomer changes, thereby changing the stiffness of the magnetorheological elastomer, realizing the stiffness adjustment of the shock absorber, and improving the shock absorbing effect of the shock absorber.

[0071] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by a person of ordinary skill in the art without departing from the spirit and technical ideas disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A magnetorheological elastomer shock absorber, characterized in that: include: A housing, wherein a mounting position is provided in the housing; An electromagnet is relatively arranged on the installation position; An adjusting mechanism is arranged between the electromagnets and is used to adjust the stiffness of the shock absorber. The adjusting mechanism comprises a magnetorheological elastomer, a magnetic conductive plate and a permanent magnet. A plurality of magnetorheological elastomers are provided, and the magnetic conductive plate is arranged between two adjacent magnetorheological elastomers. The magnetorheological elastomer and the magnetic conductive plate are stacked and arranged on the permanent magnet. The power supply module comprises a power supply and a wire, wherein the power supply is arranged outside the shell, and the power supply is connected to the electromagnet through the wire.

2. The magnetorheological elastomer shock absorber according to claim 1, characterized in that: The magnetorheological elastomer comprises a core layer part and a surface layer part, wherein the surface layer part covers the core layer part, the core layer part is filled with magnetorheological fluid and thermoplastic elastomer solution, and the surface layer part is filled with thermoplastic elastomer solution.

3. The magnetorheological elastomer shock absorber according to claim 2, characterized in that: The thermoplastic elastomer solution includes one or more of styrene-ethylene-butylene-styrene block copolymer (SEBS) solution, thermoplastic polyurethane (TPU) solution, silicone rubber (SR) solution, natural rubber (NR) solution, and styrene-butadiene rubber (SBR) solution.

4. The magnetorheological elastomer shock absorber according to claim 2, characterized in that: The thermoplastic elastic solution of the surface layer also includes conductive particles, and the conductive particles are evenly distributed in the thermoplastic elastomer solution.

5. The magnetorheological elastomer shock absorber according to claim 2, characterized in that: The iron content in the magnetorheological fluid is 30-60wt%, the mass fraction of the thermoplastic elastic solution in the surface layer is 10-50%, and the mass fraction of the thermoplastic elastomer solution in the core layer is 20-40%.

6. The magnetorheological elastomer shock absorber according to claim 1, characterized in that: The electromagnet includes an iron core and a coil, wherein the coil is wound around the iron core and electrically connected to the wire.

7. The magnetorheological elastomer shock absorber according to claim 6, characterized in that: At least two electromagnets are provided, and the winding directions of the coils of the two electromagnets are opposite.

8. The magnetorheological elastomer shock absorber according to claim 1, characterized in that: The magnetorheological elastomer and the magnetic conductive plate are stacked to form a square structure.

9. The magnetorheological elastomer shock absorber according to claim 1, characterized in that: The shell has an opening, and a protective cover for closing the installation position is arranged on the opening, and the protective cover is detachably connected to the shell.

10. A method for preparing a magnetorheological elastomer shock absorber, characterized in that: include: A thermoplastic elastomer solution and a magnetorheological fluid are prepared, and the magnetorheological fluid and a part of the thermoplastic elastomer solution are selected and mixed uniformly by mechanical stirring to obtain a mixed solution; The mixed solution is filled into the core layer, and the remaining thermoplastic elastomer solution is filled into the surface layer, and the filled surface layer covers the core layer to obtain a magnetorheological elastomer; A magnetic conductive plate is placed between two adjacent magnetorheological elastomers, a permanent magnet is placed below the lowest magnetorheological elastomer, and electromagnets are placed on the left and right sides of the magnetorheological elastomer and placed in a shell to obtain a magnetorheological elastomer shock absorber.

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