Bidirectional rigidity-adjustable composite magnetorheological elastomer vibration isolator

Abstract

The invention provides a bidirectional rigidity-adjustable composite magnetorheological elastomer vibration isolator, which belongs to the technical field of vibration isolators and comprises a base, a vertical sleeve is arranged on the base, a coil framework is arranged in the sleeve, and an electromagnetic coil is wound on the outer side of the coil framework; a permanent magnet is arranged in the coil framework, a central support is arranged above the permanent magnet, the outer side wall of the central support is fixedly connected with the inner side wall of the coil framework, a compression type MRE is arranged above the central support, and a movable magnetic conductive block is arranged above the compression type MRE; a shearing type MRE is arranged above the coil framework, and the shearing type MRE is arranged on the outer side of the movable magnetic conducting block in a sleeving mode. According to the two-way rigidity-adjustable combined type magnetorheological elastomer vibration isolator, a permanent magnet and electromagnetic coil combined magnetism supply mode is adopted, two-way rigidity adjustment and control can be achieved through current polarity switching, and power consumption of the vibration isolator can be effectively reduced; and meanwhile, by adopting a composite working mode, the vibration isolation effect of a wide frequency domain can be achieved while high bearing capacity is guaranteed.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of vibration isolators, and particularly relates to a bidirectional adjustable stiffness composite magnetorheological elastomer vibration isolator suitable for wideband precision equipment vibration control. BACKGROUND

[0002] In the fields of precision manufacturing, optical detection and semiconductor process, environmental vibration is transmitted to precision equipment through the foundation structure, which can cause dynamic deviation of the machining head or measurement unit, and even lead to reduced machining precision and shortened equipment life. Such environmental vibration usually has a wide frequency band (0-100 Hz or even higher). Traditional vibration isolation devices usually use elastic elements such as rubber and steel springs, and the stiffness and damping of the elastic elements are basically fixed after manufacturing, which cannot be self-adaptively adjusted with changes in external excitation frequency and amplitude, resulting in limited vibration isolation performance under wideband excitation and difficulty in maintaining good vibration isolation performance in the full frequency band. Although active vibration isolators can output control force in real time through actuators and control systems, they require complex sensing, control and power amplification units, have high energy consumption and cost, and are sensitive to external interference and parameter changes. Once the control system fails, the vibration isolation performance will be significantly reduced.

[0003] Magnetorheological elastomer (MRE) is a functional composite material formed by dispersing magnetic particles in a polymer matrix, and its shear and compression modulus and damping characteristics can be quickly and reversibly adjusted under the action of an external magnetic field. The material has fast response speed, good sealing performance and easy structure integration, and has become an important research direction in the field of semi-active vibration reduction and isolation.

[0004] At present, MRE vibration isolators mainly adopt a single working mode, including shear type and compression type. The shear type device has significant magnetorheological effect and large stiffness adjustment range, but has insufficient vertical bearing capacity. The compression type device has high bearing capacity and stable structure, but has a small magnetic field regulation range due to the limitation of the distance between the pole pieces and the pre-compression strain, and it is difficult to balance the high bearing capacity and wide amplitude adjustment performance. In addition, existing MRE vibration isolators generally rely on continuous excitation of the excitation coil for magnetism, which has high energy consumption and significant temperature rise, and is prone to cause material performance drift and stability decline. When the magnetic circuit design and material configuration are unreasonable, there are problems of magnetic flux leakage and local saturation, which reduce the utilization rate of magnetic flux. At the same time, the stiffness adjustment direction of the existing MRE vibration isolator is single, and it can only realize stiffness enhancement, and cannot realize bidirectional regulation of "stiffness enhancement and stiffness reduction", which is not conducive to dynamic frequency adjustment vibration isolation under different excitation frequency bands.

[0005] The above problems jointly restrict the comprehensive performance of the MRE vibration isolator in high bearing, wide magnetic control, low power consumption and long-term stability, and therefore, a composite magnetorheological elastomer vibration isolator with a shear-compression composite working mode, a permanent magnet-electromagnet hybrid excitation mechanism and a bidirectional adjustable stiffness is needed to realize high bearing and wide frequency range vibration isolation under low power consumption. SUMMARY

[0006] The present application aims at the problems of the existing magnetorheological elastomer vibration isolator, such as high power consumption, serious heat generation, difficult to balance bearing capacity and magnetic control range, and unidirectional stiffness adjustment, and provides a bidirectional adjustable stiffness composite magnetorheological elastomer vibration isolator, which realizes high bearing capacity, bidirectional stiffness adjustment in a wide magnetic control range, wide frequency band vibration isolation performance and significantly reduces operating power consumption through a permanent magnet-electromagnet hybrid excitation and a shear-compression composite working mode.

[0007] To achieve the above purpose, the present application provides a bidirectional adjustable stiffness composite magnetorheological elastomer vibration isolator, comprising a base, a vertical sleeve is arranged on the base, a coil framework is arranged in the sleeve, and an electromagnetic coil is arranged on the outer side of the coil framework.

[0008] A permanent magnet is arranged in the coil framework, a center support is arranged above the permanent magnet, the outer side wall of the center support is fixedly connected with the inner side wall of the coil framework, a compression type MRE is arranged above the center support, and a dynamic magnetic conducting block is arranged above the compression type MRE.

[0009] A shear type MRE is arranged above the coil framework, and the shear type MRE is sleeved on the outer side of the dynamic magnetic conducting block.

[0010] Further, a circular first groove is arranged at the center of the lower surface of the center support, the permanent magnet is arranged in the first groove, and the permanent magnet is fixedly connected with the center support.

[0011] A circular second groove is arranged at the center of the upper surface of the center support, the bottom of the compression type MRE is arranged in the second groove, and the compression type MRE is hingedly fixed with the center support.

[0012] Further, the depth of the first groove = the height of the permanent magnet, and the depth of the second groove < the depth of the first groove.

[0013] Further, the dynamic magnetic conducting block comprises a vertical cylindrical part, the lower end of the cylindrical part is hingedly fixed with the upper surface of the compression type MRE, and a screw hole for connecting a vibration-isolated object is arranged at the center of the upper surface of the cylindrical part.

[0014] The outer side wall of the cylindrical part is fixedly sleeved with a ring part, the ring part is located at the middle upper part of the cylindrical part, and the ring part is located above the coil framework, and the shear type MRE is fixedly sleeved on the outer side wall of the ring part.

[0015] Further, the diameter of the cylindrical part is less than the inner diameter of the coil framework, and a spacing is left between the ring part and the coil framework.

[0016] Further, a gasket is sleeved on the movable magnetic conducting block, and the gasket is located between the shear type MRE and the coil framework.

[0017] Further, the movable magnetic conducting block, the sleeve, the center support and the base are made of magnetic conducting material, and the gasket and the coil framework are made of non-magnetic conducting material.

[0018] Further, the magnetic field direction of the permanent magnet is a positive magnetic field;

[0019] When the electromagnetic coil generates a magnetic field in the positive current, the direction of the magnetic field generated by the permanent magnet is the same as that of the electromagnetic coil;

[0020] When the electromagnetic coil generates a magnetic field in the reverse current, the direction of the magnetic field generated by the permanent magnet is opposite to that of the electromagnetic coil.

[0021] Further, a plurality of screws for fixing the base and the sleeve are further included, a plurality of the screws are located at the bottom of the base, and a plurality of the screws are arranged in a circle with the center of the sleeve as the center, and the sleeve and the base are fixedly connected through the screws.

[0022] The present application has the following beneficial effects:

[0023] (1) The present application adopts a hybrid excitation mode combining permanent magnet and electromagnetic coil, the permanent magnet provides a basic bias magnetic field, so that the vibration isolator has stable carrying capacity and basic stiffness in the zero current state, the electromagnetic coil is only powered for a short time when the stiffness needs to be adjusted, and the positive or reverse current is respectively superimposed with the magnetic field of the permanent magnet in the same direction or in the opposite direction, so that the stiffness is enhanced or weakened, the power consumption and heating risk of long-term power supply of the coil are significantly reduced, and the service life of the magnetorheological elastomer material is improved.

[0024] (2) The present application parallelly arranges the compression type MRE and the shear type MRE in the same vibration isolator, the compression type MRE bears the main vertical load, and the shear type MRE provides a large magnetic control stiffness adjustment range. The two working mode structures are integrated through the movable magnetic conducting block, so that the high carrying capacity of the vibration isolator is ensured, the stiffness adjustment range is expanded, and the carrying capacity and the magnetic control performance are cooperatively optimized.

[0025] (3) The magnetic field formed by the permanent-magnetic and electromagnetic hybrid excitation can be forward and reverse regulated, and the magnetic induction intensity of the shear type MRE and the compression type MRE can be bidirectionally regulated, so that the equivalent stiffness of the vibration isolator can be bidirectionally adjusted, the stiffness can be actively increased or decreased in different environmental vibration working conditions, the inherent frequency of the system can be shifted to the high frequency or low frequency side in a certain range, the main excitation band can be avoided, and the wideband vibration isolation performance is improved.

[0026] (4) The structure is compact, the sleeve, the center support, the movable magnetic conducting block and the base are made of magnetic conducting materials, the coil framework and the gasket are made of non-magnetic conducting materials, the magnetic flux path is clear, the magnetic circuit leakage can be effectively reduced, the utilization rate of the magnetic field generated by the permanent magnet and the electromagnetic coil is improved, and the application in scenes such as basic vibration isolation of precision instruments, equipment-basic vibration isolation and local vibration isolation of building structures is suitable.

[0027] The application will be described in detail below with reference to the drawings and embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a structural schematic diagram of the application.

[0029] Figure 2 is a first structural cross-sectional view of the application.

[0030] Figure 3 is a second structural cross-sectional view of the application.

[0031] Figure 4 is a first schematic diagram of the magnetic field loop of the application.

[0032] Figure 5 is a second schematic diagram of the magnetic field loop of the application.

[0033] The reference signs are explained as follows: 1, base; 2, sleeve; 3, coil framework; 4, electromagnetic coil; 5, permanent magnet; 6, center support; 7, compression type MRE; 8, movable magnetic conducting block; 81, cylindrical part; 82, screw hole; 83, annular part; 9, shear type MRE; 10, first groove; 11, second groove; 12, gasket; 13, screw. DETAILED DESCRIPTION

[0034] In order to further explain the technical means and effects adopted by the application to achieve the predetermined purpose, the specific implementation, structural features and effects of the application are described in detail as follows by combining the drawings and embodiments.

[0035] Clearly, the described embodiments are merely a part of the embodiments of the present application, but not all the embodiments thereof. Based on the embodiments of the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative effort should fall within the protection scope of the present application.

[0036] In the description of the present application, it should be understood that the terms "center", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "alignment", "overlap", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are merely for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0037] The terms "first", "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features; in the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0038] Embodiment 1

[0039] The present embodiment provides a bidirectional adjustable stiffness composite magneto-rheological elastomer vibration isolator as shown in Figures 1-5 The present embodiment provides a bidirectional adjustable stiffness composite magneto-rheological elastomer vibration isolator as shown in

[0040] The coil former 3 is provided with a permanent magnet 5, the permanent magnet 5 is located at the center of the bottom of the coil former 3, and the permanent magnet 5 is fixedly connected with the base 1, the upper side of the permanent magnet 5 is provided with a center support 6, the outer side wall of the center support 6 is fixedly connected with the inner side wall of the coil former 3, the upper side of the center support 6 is provided with a compression type MRE 7, the compression type MRE 7 is a compression type magneto-rheological elastomer, the upper side of the compression type MRE 7 is provided with a movable magnetic conducting block 8.

[0041] A shear type MRE 9 is arranged above the coil former 3, the shear type MRE 9 is a shear type magneto-rheological elastomer, and the shear type MRE 9 is sleeved on the outer side of the dynamic flux guide 8, so as to form a “shear-compression” composite working mode. The dynamic flux guide 8 includes a vertical cylinder part 81, the lower end of the cylinder part 81 is fixedly connected to the upper surface of the compression type MRE 7 through structural glue, a screw hole 82 for connecting a vibration-isolated object is arranged at the center of the upper surface of the cylinder part 81, a circular ring part 83 is fixedly sleeved on the outer side wall of the cylinder part 81, the circular ring part 83 is located at the middle upper part of the cylinder part 81, and the circular ring part 83 is located above the coil former 3, the shear type MRE 9 is fixedly sleeved on the outer side wall of the circular ring part 83, the outer side wall of the shear type MRE 9 is fixedly connected to the inner side wall of the sleeve 2, the diameter of the cylinder part 81 is less than the inner diameter of the coil former 3, and the diameter of the cylinder part 81 is 2-3 mm smaller than the inner diameter of the coil former 3, so as to ensure that the dynamic flux guide 8 of the vibration isolator moves up and down when vertically damping, a spacing is left between the circular ring part 83 and the coil former 3, so as to ensure that the dynamic flux guide 8 of the vibration isolator moves up and down when vertically damping, a gasket 12 is sleeved on the dynamic flux guide 8, the gasket 12 is located between the shear type MRE 9 and the coil former 3, the outer side wall of the gasket 12 is fixedly connected to the inner side wall of the sleeve 2, and the lower surface of the gasket 12 is fixedly connected to the upper surface of the coil former 3.

[0042] Further, a circular first recess 10 is arranged at the center of the lower surface of the central support 6, the diameter of the first recess 10 is matched with the size of the permanent magnet 5, the permanent magnet 5 is located in the first recess 10, and the permanent magnet 5 is fixedly connected to the central support 6.

[0043] A circular second recess 11 is arranged at the center of the upper surface of the central support 6, the diameter of the second recess 11 is matched with the size of the compression type MRE 7, the bottom of the compression type MRE 7 is located in the second recess 11, and the compression type MRE 7 is fixedly connected to the bottom surface of the second recess 11 through structural glue, wherein the depth of the first recess 10 is equal to the height of the permanent magnet 5, and the depth of the second recess 11 is less than the depth of the first recess 10.

[0044] In combination Figures 1-5 , the screw hole 82 at the upper end of the cylinder part 81 of the dynamic flux guide 8 is connected to a vibration-isolated object through a bolt, and the base 1 is fixed to the ground through a bolt. During the operation of the machine, the ground may be vibrated due to surrounding equipment or subway and other factors. Therefore, an acceleration sensor is arranged on the ground around the vibration isolator. According to the vibration signal detected by the sensor, the feedback control algorithm built in the controller calculates the control current required by the driving magneto-rheological elastomer vibration isolator in real time, and the control current is input into the electromagnetic coil 4 in the vibration isolator, so as to change the magnetic field synthesized by the electromagnetic coil 4 and the permanent magnet 5, and further change the stiffness and damping of the magneto-rheological elastomer, so as to achieve the effect of wide frequency domain vibration isolation.

[0045] Wherein, the feedback control algorithm adopts PID control algorithm based on acceleration feedback. Let the ground acceleration measured by the acceleration sensor be , and the target acceleration set be , then the error signal is . The control current of the electromagnetic coil 4 output by the controller is :

[0046] ,

[0047] Wherein, , , are proportional, integral and differential coefficients respectively, which can be determined according to the dynamic characteristics of the vibration isolation system by using conventional setting method. In other embodiments, the feedback control algorithm can also be a semi-active control algorithm such as skyhook control, fuzzy control and the like known to those skilled in the art, and the present application is not limited in the specific form of the control algorithm.

[0048] When the vibration is generated, the vibration isolator connected to the ground produces reciprocating motion in the vertical direction, and the compression type MRE 7 produces compression-stretching deformation, and the shear type MRE 9 produces reciprocating shear deformation up and down, thereby achieving the effect of vibration isolation. Compared with the traditional magneto-rheological elastomer vibration isolator, the vibration isolator of the present application adopts a permanent magnet-electromagnetic hybrid excitation magnetic circuit structure: the permanent magnet provides a basic bias magnetic field, so that the vibration isolator has a pre-set stiffness reserve in the zero current state; when the electromagnetic coil passes through the control current, the magnetic potential field generated by the electromagnetic excitation unit and the magnetic potential field vector of the permanent magnet unit are synthesized, which can realize the multiple superposition of magnetic field intensity in the same direction excitation, form the magnetic flux density enhancement effect, and reduce the magnetic flux density and produce the stiffness attenuation characteristics in the opposite excitation, thereby realizing the bidirectional adjustable stiffness.

[0049] Further, the magnetic field direction of the permanent magnet 5 is a positive magnetic field, and when the electromagnetic coil 4 passes through a positive current, the generated magnetic field has the same direction as the magnetic field generated by the permanent magnet 5, which is a positive magnetic field, forming a magnetic circuit as shown in the figure;

[0050] When the electromagnetic coil 4 passes through a reverse current, the generated magnetic field has the opposite direction to the magnetic field generated by the permanent magnet 5, which is a reverse magnetic field, forming a magnetic circuit as shown in the figure.

[0051] In the same direction current working condition, as shown in Figure 4 , only a small current input is needed to obtain a significant magnetic circuit strengthening effect, thereby achieving the goal of energy efficiency optimization, and when the reverse magnetic field is regulated, as shown in Figure 5 , a negative stiffness adjustment mechanism can be formed as the current intensity increases

[0052] Further, the magnetic conducting block 8, the sleeve 2, the center support 6 and the base 1 are made of magnetic conducting material, such as pure iron, and the gasket 12 and the coil framework 3 are made of non-magnetic conducting material, such as aluminum alloy for the gasket 12 and resin for the coil framework 3.

[0053] To sum up, the bidirectional adjustable stiffness composite magneto-rheological elastomer vibration isolator provided by the application adopts a magnetic supply mode combining permanent magnets 5 and electromagnetic coils 4, can realize bidirectional regulation and control of stiffness through current polarity switching, and can effectively reduce the power consumption of the vibration isolator; at the same time, through the adoption of a composite working mode, high bearing capacity can be ensured while wide frequency domain vibration isolation effect can be realized.

[0054] The above is a further detailed description of the application in combination with specific preferred embodiments, and the specific implementation of the application cannot be limited to these descriptions. For ordinary skilled persons in the technical field to which the application belongs, some simple deductions or substitutions can be made without departing from the concept of the application, and all of them shall be regarded as falling within the protection scope of the application.

Claims

1. A bidirectional adjustable stiffness composite magnetorheological elastomer vibration isolator, characterized in that: Includes a base (1), on which a vertical sleeve (2) is provided, and a coil frame (3) is provided inside the sleeve (2), and an electromagnetic coil (4) is wound around the outside of the coil frame (3); The coil frame (3) is provided with a permanent magnet (5), and a central support (6) is provided above the permanent magnet (5). The outer side wall of the central support (6) is fixedly connected to the inner side wall of the coil frame (3). A compression type MRE (7) is provided above the central support (6), and a moving magnetic block (8) is provided above the compression type MRE (7). A shear-type MRE (9) is provided above the coil frame (3), and the shear-type MRE (9) is sleeved on the outside of the moving magnetic block (8).

2. The bidirectional adjustable stiffness composite magnetorheological elastomer vibration isolator as described in claim 1, characterized in that: A circular first groove (10) is provided at the center of the lower surface of the central support (6), the permanent magnet (5) is located in the first groove (10), and the permanent magnet (5) is fixedly connected to the central support (6); A circular second groove (11) is provided at the center of the upper surface of the central support (6), the bottom of the compressed new MRE is located in the second groove (11), and the compressed MRE (7) is hinged and fixed to the central support (6).

3. The bidirectional adjustable stiffness composite magnetorheological elastomer vibration isolator as described in claim 2, characterized in that: The depth of the first groove (10) is equal to the height of the permanent magnet (5), and the depth of the second groove (11) is less than the depth of the first groove (10).

4. The bidirectional adjustable stiffness composite magnetorheological elastomer vibration isolator as described in claim 1, characterized in that: The moving magnetic block (8) includes a vertically arranged cylindrical part (81), the lower end of which is hinged to the upper surface of the compression type MRE (7), and a screw hole (82) for connecting the vibration-isolated object is provided at the center of the upper surface of the cylindrical part (81). A ring portion (83) is fixedly sleeved on the outer wall of the cylindrical portion (81). The ring portion (83) is located in the upper middle part of the cylindrical portion (81) and above the coil frame (3). The shear-type MRE (9) is fixedly sleeved on the outer wall of the ring portion (83).

5. The bidirectional adjustable stiffness composite magnetorheological elastomer vibration isolator as described in claim 4, characterized in that: The diameter of the cylindrical part (81) is less than the inner diameter of the coil frame (3), and there is a gap between the annular part (83) and the coil frame (3).

6. The bidirectional adjustable stiffness composite magnetorheological elastomer vibration isolator as described in claim 5, characterized in that: A washer (12) is fitted on the moving magnetic block (8), and the washer (12) is located between the shear-type MRE (9) and the coil frame (3).

7. A bidirectional adjustable stiffness composite magnetorheological elastomer vibration isolator as described in claim 6, characterized in that: The moving magnetic block (8), the sleeve (2), the central support (6) and the base (1) are all made of magnetic materials, while the washer (12) and the coil frame (3) are made of non-magnetic materials.

8. The bidirectional adjustable stiffness composite magnetorheological elastomer vibration isolator as described in claim 1, characterized in that: The magnetic field direction of the permanent magnet (5) is a positive magnetic field; When the electromagnetic coil (4) is supplied with a positive current, the magnetic field generated is in the same direction as the magnetic field generated by the permanent magnet (5); When the electromagnetic coil (4) is supplied with a reverse current, the magnetic field generated is opposite in direction to the magnetic field generated by the permanent magnet (5).

9. A bidirectional adjustable stiffness composite magnetorheological elastomer vibration isolator as described in claim 1, characterized in that: It also includes a plurality of screws (13) for fixing the base (1) and the sleeve (2). The plurality of screws (13) are located at the bottom of the base (1) and are arranged in a circle with the center of the sleeve (2) as the center. The sleeve (2) and the base (1) are fixedly connected by the screws (13).

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