A turntable vibration reduction device and method based on eddy current effect

Abstract

The present invention belongs to the technical field of vibration control devices, and specifically discloses a turntable vibration reduction device and method based on the eddy current effect. The device includes a turntable, which includes a rotating shaft and a turntable. The turntable is fixed to the upper end of the rotating shaft. The rotating shaft can drive the turntable to rotate. A permanent magnet is installed on the edge of the turntable. A conductor tube is installed on the outer side of the turntable. The permanent magnet and the conductor tube are in a clearance fit. A motor is installed on the turntable. The motor is connected to a conductor patch through a force arm. The conductor patch is located between the permanent magnet and the conductor tube. The motor can drive the force arm to rotate, thereby driving the conductor patch to move, changing the area blocked by the conductor patch to the permanent magnet and the conductor tube. The present invention can adjust the patch position by controlling the motor to change the damping coefficient of the device. The present invention is essentially a non-contact vibration reduction method, so it can be made into a lightweight structure. Unlike previous pipeline noise control methods, it has fewer additional devices and less impact on the pipeline itself.

Description

Technical Field

[0001] The present invention relates to the technical field of vibration control equipment, and in particular to a turntable vibration reduction device and method based on eddy current effect. Background Art

[0002] Five-axis machine tools are essential equipment for machining key aircraft engine components such as impellers and blades. Direct-drive rotary tables are key functional components. Rotary tables are susceptible to vibrations caused by external excitation, severely reducing part machining accuracy. Research on vibration control measures using adjustable damping for direct-drive rotary tables has important practical applications. Selecting an appropriate damping coefficient can improve vibration characteristics and reduce system response time. When the damping ratio falls below a certain threshold, the system becomes unstable, resulting in uncontrollable oscillations. When the damping ratio exceeds the critical damping ratio, the system becomes overstable, increasing static error and slowing response time. Therefore, to ensure system stability, an appropriate damping value must be selected. Research on the nonlinear dynamic characteristics of spiral bevel gear systems supported by squeeze film dampers clearly demonstrates that excessive or insufficient damping can lead to problems. SFDs can effectively suppress vibrations above the critical speed and improve the system's non-periodic motion. Furthermore, there is an optimal damper length design; excessive or insufficient damping can lead to bistability and jumps.

[0003] Existing vibration reduction applications include steel ball dampers, which utilize energy loss from collisions of masses, and electrorheological dampers, which exploit the electrorheological effect. However, the steel balls generate noise during operation, and electrorheological dampers require high applied voltages, raising safety concerns. Since their introduction, electromagnetic dampers have attracted considerable research interest, offering advantages such as a simple structure, significant damping effect, and the absence of an external energy source. However, many existing electromagnetic dampers are only suitable for linear motion and are incapable of reducing vibration in rotational motion.

[0004] Patent application number CN 109780109A, titled "Electromagnetic Damper Structure and Electromagnetic Damper," discloses an electromagnetic vibration damping device comprising a damping matrix, a rotating matrix, a base, a magnetic field structure, a stator structure, and a rotor structure. The magnetic field structure provides a stable magnetic field, the stator structure dissipates energy, and the rotor structure controls vibration. While this patent has a vibration damping effect, the structure is complex, requiring extensive external installations outside the rotating matrix, and lacks adjustable vibration damping. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a turntable vibration reduction device based on eddy current effect in view of the above-mentioned deficiencies in the prior art.

[0006] In order to achieve the above technical objectives, the technical solution adopted by the present invention is:

[0007] A turntable vibration reduction device based on eddy current effect includes a turntable, which includes a rotating shaft and a turntable. The turntable is fixed to the upper end of the rotating shaft, and the rotating shaft can drive the turntable to rotate. A permanent magnet is installed on the edge of the turntable, and a conductor tube is installed on the outer side of the turntable. The permanent magnet and the conductor tube are clearance-matched. A motor is installed on the turntable, and the motor is connected to a conductor patch through a force arm. The conductor patch is located between the permanent magnet and the conductor tube. The motor can drive the force arm to rotate, thereby driving the conductor patch to move, thereby changing the shielding area of ​​the conductor patch on the permanent magnet and the conductor tube.

[0008] To optimize the above technical solutions, specific measures taken also include:

[0009] The conductor tube is a cylindrical tube, which is sleeved on the outside of the turntable. The axis of the conductor tube coincides with the axis of the turntable, and the permanent magnet is gap-fitted with the inner wall of the conductor tube.

[0010] The rotating shaft comprises a rotating base, a bearing support and a bearing. The bearing support is fixed on the rotating base. The bearing is rotatably mounted on the bearing support. The bearing is fixedly connected to the turntable.

[0011] A base is provided below the rotating base, the lower end of the torsion spring is fixedly connected to the base, and the upper end is fixedly connected to the rotating base.

[0012] An annular conductor tube base is fixed on the base, and the lower end of the conductor tube is fixed on the conductor tube base.

[0013] The motor is connected to a controller, which is used to control the operation of the motor.

[0014] There are several permanent magnets mentioned above, which are arranged at the edge of the turntable in equal arcs. Correspondingly, the number of conductor patches is equal to the number of permanent magnets, and each permanent magnet is provided with a corresponding conductor patch.

[0015] The permanent magnet is a neodymium iron cobalt magnet.

[0016] The material used for the above-mentioned conductor tube is copper.

[0017] The base is connected to the conductor tube bottom base via screws.

[0018] A turntable vibration reduction method based on eddy current effect is characterized by applying the above-mentioned turntable vibration reduction device, specifically comprising the following steps:

[0019] Step 1: Determine the target value C of the electromagnetic damping coefficient of the turntable vibration reduction device based on the turntable vibration characteristics and the response time requirements of the turntable system. ec ;

[0020] Step 2: Calculate and derive the exposed area between the permanent magnet and the conductor tube based on the target value of the electromagnetic damping coefficient;

[0021] Step 3: Calculate the shielding area based on the exposed area, and control the motor to adjust the position of the conductor patch so that the conductor patch reaches a predetermined position to shield the calculated shielding area.

[0022] In step 2, the specific method for calculating and deriving the exposed area between the permanent magnet and the conductor tube is:

[0023] Ignoring the small bending between the permanent magnet and the conductor tube, if the relative speed between the magnet and the conductor tube is v, the motional electromotive force is generated.

[0024] ε=Bvb (1)

[0025] Current

[0026]

[0027] a is the length of the permanent magnet, da is the small increment in the length direction of the permanent magnet;

[0028] According to Ampere's law, the Ampere force generated by the induced current is opposite to the velocity, and the magnitude of the Ampere force is:

[0029]

[0030] Finally, the electromagnetic damping force is obtained by integrating in the direction of the exposed length a of the permanent magnet.

[0031]

[0032] Where B is the magnitude of the magnetic field, t is the thickness of the conductor plate, b is the exposed width of the permanent magnet, R is the middle radius of the permanent magnet, α is the angle of the permanent magnet, ρ is the conductivity of the conductor plate (3), and the target value of the electromagnetic damping coefficient C is ec :

[0033]

[0034] The exposed area between the permanent magnet and the conductor tube is a×b. Assuming that the conductor patch only blocks the permanent magnet in the width direction, the conductor patch is moved to change the value of the exposed width b of the permanent magnet so that both sides of Equation 95) are equal.

[0035] The present invention has the following advantages:

[0036] (1) The present invention applies the electromagnetic damper to the turntable and its rotational motion, which has a good vibration reduction effect on the low-frequency vibration of the turntable.

[0037] (2) Since the vibration reduction design method of the present invention is supported by corresponding theories and simulation results, it has strong scalability and broad design space in future designs.

[0038] (3) Since the present invention uses a small number of components and has a simple structure, it has a short construction period and significant design effect, and has certain practical engineering application value.

[0039] (4) Since the present invention is essentially a non-contact vibration reduction method, it can be made into a lightweight structure. Unlike previous pipeline noise control methods, it requires fewer additional devices and has less impact on the pipeline itself.

[0040] (5) The present invention can adjust the position of the patch by controlling the motor and change the damping coefficient of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is a schematic diagram of the structure of the electromagnetic damper based on the eddy current effect from the first perspective;

[0042] Figure 2 is a structural schematic diagram of the electromagnetic damper structure at a second viewing angle;

[0043] Figure 3 This is a schematic diagram of the structure of the electromagnetic damper adjusting the damping coefficient from the second perspective.

[0044] Figure 4 is the cross section of the working part of the electromagnetic damper;

[0045] Figure 5 It is a simplified schematic diagram of the electromagnetic damper single degree of freedom system;

[0046] Figure 6 This is a diagram of the mechanism of action of the permanent magnet microelement in the present invention;

[0047] Figure 7 The graph shows the vibration isolation curves (experimental results) of electromagnetic dampers loaded with 0, 2, and 4 permanent magnets.

[0048] The reference numerals in the figure are: 1. turntable; 2. permanent magnet; 3. conductor tube; 4. conductor tube base; 5. base; 6. bearing; 7. bearing support; 8. rotating base; 9. torsion spring; 10. conductor patch; 11. motor; 12. controller; 13. lever arm. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical solutions and advantages of this application more clearly understood, the present application is described and illustrated below in conjunction with the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely used to explain this application and are not intended to limit this application. Based on the embodiments provided in this application, all other embodiments obtained by those of ordinary skill in the art without making any creative efforts are within the scope of protection of this application.

[0050] Obviously, the drawings described below are merely examples or embodiments of the present application. Those skilled in the art can, without inventive effort, apply the present application to other similar scenarios based on these drawings. Furthermore, it is also understood that, although the effort involved in such a development process may be complex and lengthy, for those skilled in the art related to the content disclosed in this application, changes in design, manufacturing, or production based on the technical content disclosed in this application are merely conventional technical means and should not be construed as an insufficiency of the content disclosed in this application.

[0051] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it refer to independent or alternative embodiments that are mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described in this application may be combined with other embodiments unless there is a conflict.

[0052] Unless otherwise defined, the technical or scientific terms used in this application should have the ordinary meaning understood by a person of ordinary skill in the technical field to which this application belongs. The words "a", "an", "a", "the" and the like used in this application do not indicate a limit on quantity and may indicate the singular or plural. The terms "include", "comprise", "have" and any variations thereof used in this application are intended to cover non-exclusive inclusions; for example, a process, method, system, product or device that includes a series of steps or units (units) is not limited to the listed steps or units, but may also include steps or units that are not listed, or may also include other steps or units that are inherent to these processes, methods, products or devices. The words "connect", "connected", "coupled" and the like used in this application are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The words "multiple" / "several" used in this application refer to two or more. "And / or" describes the association relationship between associated objects, indicating that three relationships can exist. For example, "A and / or B" can mean: A exists alone, A and B exist at the same time, or B exists alone. The character " / " generally indicates that the objects before and after are in an "or" relationship. The terms "first", "second", "third", etc. involved in this application are only used to distinguish similar objects and do not represent a specific order for the objects.

[0053] refer to Figure 1 and 2The present invention is a turntable vibration reduction device based on the eddy current effect. The main technical features are: a permanent magnet 2 is mounted on the surface of a turntable 1, a conductor tube 3 is mounted on a conductor tube base 4, and the structural parameters of the conductor tube 3 are changed according to the size of the turntable. The eddy current effect is used to eliminate the vibration of the turntable. The specific implementation scheme is as follows:

[0054] The direct-drive turntable electromagnetic damper structure designed by the present invention includes a turntable, a permanent magnet 2 is installed in the groove of the turntable's turntable 1, a conductor patch 10 is installed on the surface of the permanent magnet 2, a conductor tube 3 is installed on the outside of the turntable 1, and the axis of the conductor tube 3 coincides with the axis of the turntable 1. The bearing 6 is installed under the turntable 1, and the bearing base 7 and the bottom base 4 of the conductor tube jointly limit the movement of the bearing 6. The torsion spring 9 is installed between the rotating base 8 and the base 5 to provide a restoring force. The motor 11 is installed in the groove of the turntable 1, and the controller 12 is installed on the surface of the motor. The motor is connected to the arm 13, and the arm 13 is connected to the conductor patch 10. By controlling the motor to change the position of the conductor patch 10, the exposed area of ​​the permanent magnet 2 and the conductor tube 3 is changed, thereby changing the damping coefficient. The permanent magnet 2 is a rigid material, such as a neodymium iron cobalt magnet. During the installation process, it is necessary to ensure that the position of the permanent magnet 2 is symmetrical to avoid eccentric torque during the rotation of the turntable 1. The natural frequency of the electromagnetic damper structure is determined by a simplified single-degree-of-freedom model, with reference to Figure 5 , Figure 5 Where k is the torsional stiffness of the simplified model, j is the moment of inertia of the model, and Cec is the equivalent damping of the model.

[0055] refer to Figure 4 The turntable 1 vibrates under external excitation, and the permanent magnet 2 on the surface of the turntable and the conductor tube 3 rotate relative to each other. The magnetic field changes dramatically, and eddy currents are generated in the conductor tube 3. These movable electrons will react to the magnetic field, generating a Lorentz force opposite to the speed of movement, hindering the rotation of the turntable 1, and ultimately converting the mechanical energy of the turntable 1 into heat energy dissipation, achieving the effect of vibration reduction.

[0056] refer to Figure 6 , combined with the action mode of permanent magnet 2, calculate and derive the electromagnetic damping coefficient. If the relative speed between magnet 2 and conductor plate 3 is v, motional electromotive force is generated.

[0057] ε=Bvb (1)

[0058] Current

[0059]

[0060] a is the length of the permanent magnet, da is the small increment in the length direction of the permanent magnet;

[0061] According to Ampere's law, the Ampere force generated by the induced current is opposite to the velocity, and the magnitude of the Ampere force is:

[0062]

[0063] Finally, the electromagnetic damping force is obtained by integrating in the direction of the exposed length a of the permanent magnet.

[0064]

[0065] Where B is the magnetic field size, t is the thickness of the conductor plate, b is the exposed width of the permanent magnet, R is the middle radius of the permanent magnet. The permanent magnet 2 is a partial arc structure in the model. The middle radius is the distance from the middle plane of the arc to the center of the circle. α is the angle of the permanent magnet. The permanent magnet 2 is a partial arc structure in the model. α refers to the angle of the arc part. ρ is the conductivity of the conductor plate 3. The target value of the electromagnetic damping coefficient C is ec :

[0066]

[0067] The exposed area between the permanent magnet and the conductor tube is a×b. Assuming that the conductor patch only blocks the permanent magnet in the width direction, the conductor patch is moved to change the value of the exposed width b of the permanent magnet so that both sides of equation (5) are equal.

[0068] The following is a further detailed description of the implementation methods and vibration isolation mechanism of the invention with reference to the accompanying drawings and examples:

[0069] The turntable 1 and the rotating base 8 are made of rigid materials. It is assumed that they will not be torsionally deformed or broken under the action of external forces. A plurality of permanent magnets 2 are installed in the grooves of the turntable 1. The permanent magnets 2 are magnetically connected to the surface of the turntable 1. The boundary condition of the connection is fixed support. The specific number of permanent magnets 2 can be determined according to the vibration reduction requirements, which include parameters such as peak frequency. When installing the permanent magnets 2, the eccentric moment of inertia generated by the asymmetric structure during rotation should be avoided. The conductor patch 10 is installed on the surface of the permanent magnet 2 to change its exposed area. The conductor tube 3 is installed on the outer surface of the conductor tube base 4. The difference between the tube magnetic gap and the thickness of the permanent magnet should not be too large. The connection between the turntable 1 and the conductor tube base 4 depends on the torsion spring 9 and the base 5. The base 5 is screwed to the conductor tube base 4. The torsion spring 9 provides the only mechanical restoring force for the electromagnetic damper structure.

[0070] The rigid material of the turntable 1 can be common carbon steel or directly selected according to the required application scenario, as long as the magnetic force between the permanent magnet 2 and the turntable 1 is much larger than the Lorentz force.

[0071] The permanent magnet 2 is a circular rigid magnet, and is usually a magnet with strong magnetic properties such as a common neodymium iron cobalt magnet.

[0072] The thickness of the permanent magnet 2 should be of the same order of magnitude as the tube magnetic gap to ensure the strength of the magnetic field on the surface of the conductor tube 3 .

[0073] The conductor tube 3 can be connected to the support during actual installation, and the two are fixedly supported. Common materials such as copper are usually used, which are not attracted by permanent magnets and have good conductivity.

[0074] The torsional stiffness of the torsion spring 9 should be much greater than the torsional stiffness of the turntable 1 to comply with the rigid body assumption of the turntable 1 .

[0075] The following parameters are used in this case to illustrate the vibration reduction mechanism: The moment of inertia of the turntable 1 system is 7.9e-4kg*m 2 The torsional stiffness of the torsion spring 9 is 7.819 N*m / rad, the radius of the turntable 1 is 50 mm, the thickness of the permanent magnet 2 is 5 mm, and the damping ratio is 0.2378.

[0076] When an external excitation is applied to the turntable 1, the turntable 1 will vibrate. The excitation force applied by the hammer is instantaneous. When it is expanded into a Fourier series form, the linear accumulation of periodic excitations of different frequencies can be obtained, and the frequency domain response, peak frequency and vibration reduction performance of the damper can be analyzed. When the number of permanent magnets 2 is 0, 2, and 4, the vibration reduction effect of the experimental results is obvious (such as Figure 7 The number of electromagnetic dampers has a significant effect on the peak amplitude. The peak amplitudes for no magnet, two magnets, and four magnets are 9.54e-3, 2.90e-3, and 1.90e-3, respectively, and the peak amplitude decreases by three times.

[0077] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions based on the principles of the present invention are within the scope of protection of the present invention. It should be noted that for those skilled in the art, various improvements and modifications that do not depart from the principles of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A turntable vibration reduction device based on eddy current effect, comprising a turntable, wherein the turntable comprises a rotating shaft and a turntable (1), wherein the turntable (1) is fixed to the upper end of the rotating shaft, and the rotating shaft can drive the turntable (1) to rotate, wherein: A permanent magnet (2) is installed on the edge of the turntable (1), a conductor tube (3) is installed on the outer side of the turntable, the permanent magnet (2) and the conductor tube (3) are clearance-matched, a motor (11) is installed on the turntable, the motor (11) is connected to the conductor patch (10) through a force arm (13), the conductor patch (10) is located between the permanent magnet (2) and the conductor tube (3), the motor (11) can drive the force arm (13) to rotate, and then drive the conductor patch (10) to move, thereby changing the shielding area of ​​the conductor patch (10) on the permanent magnet (2) and the conductor tube (3).

2. The turntable vibration reduction device based on eddy current effect according to claim 1, characterized in that: The conductor tube (3) is a cylindrical tube, which is sleeved on the outside of the turntable. The axis of the conductor tube (3) coincides with the axis of the turntable, and the permanent magnet (2) is gap-matched with the inner wall of the conductor tube (3).

3. The turntable vibration reduction device based on eddy current effect according to claim 2, characterized in that: The rotating shaft comprises a rotating base (8), a bearing support (7) and a bearing (6); the bearing support (7) is fixed on the rotating base (8); the bearing (6) is rotatably mounted on the bearing support (7); and the bearing (6) is fixedly connected to the turntable (1).

4. The turntable vibration reduction device based on eddy current effect according to claim 3 is characterized in that: A base (5) is provided below the rotating base (8); the lower end of the torsion spring (9) is fixedly connected to the base (5), and the upper end is fixedly connected to the rotating base (8).

5. The turntable vibration reduction device based on eddy current effect according to claim 4 is characterized in that: An annular conductor tube base (4) is fixed on the base (5), and the lower end of the conductor tube (3) is fixed on the conductor tube base (4).

6. The turntable vibration reduction device based on eddy current effect according to claim 5, characterized in that: The motor (11) is connected to a controller (12), and the controller (12) is used to control the operation of the motor (11).

7. The turntable vibration reduction device based on eddy current effect according to claim 1, characterized in that: The number of the permanent magnets (2) is several, and the permanent magnets (2) are arranged at the edge of the turntable (1) in equal arcs. Correspondingly, the number of the conductor patches (10) is equal to the number of the permanent magnets (2), and each permanent magnet (2) is provided with a corresponding conductor patch (10).

8. The turntable vibration reduction device based on eddy current effect according to claim 5, characterized in that: The permanent magnet (2) is a neodymium iron cobalt magnet; the material used for the conductor tube (3) is copper; and the base (5) is connected to the conductor tube base (4) via screws.

9. A turntable vibration reduction method based on eddy current effect, characterized by: The application of the turntable vibration reduction device according to claim 1 specifically includes the following steps: Step 1: Determine the target value of the electromagnetic damping coefficient of the turntable vibration reduction device based on the turntable vibration characteristics and the response time requirements of the turntable system. ; Step 2: Calculate and derive the exposed area between the permanent magnet (2) and the conductor tube (3) based on the target value of the electromagnetic damping coefficient; Step 3: Calculate the shielding area based on the exposed area, and control the motor (11) to adjust the position of the conductor patch (10) so that the conductor patch (10) reaches a predetermined position to shield the calculated shielding area.

10. The turntable vibration reduction method based on eddy current effect according to claim 9, characterized in that: In step 2, the specific method for calculating and deriving the exposed area between the permanent magnet (2) and the conductor tube (3) is: Ignoring the small bending between the permanent magnet (2) and the conductor tube (3), if the relative speed between the permanent magnet (2) and the conductor tube (3) is , generating motional electromotive force （1） Current （2） is the length of the permanent magnet, is a small increment in the length direction of the permanent magnet; According to Ampere's law, the Ampere force generated by the induced current is opposite to the velocity, and the magnitude of the Ampere force is: （3） Finally, the exposed length of the permanent magnet Integrate in the direction to obtain the electromagnetic damping force （4） Where, is the magnitude of the magnetic field, is the thickness of the conductor tube (3), is the exposed width of the permanent magnet (2), is the middle radius of the permanent magnet (2), is the angle of the permanent magnet (2), is the conductivity of the conductor tube (3), the target value of the electromagnetic damping coefficient : （5） The exposed area between the permanent magnet (2) and the conductor tube (3) is If the conductor patch (10) only blocks the permanent magnet (2) in the width direction, the conductor patch (10) is moved to change the exposed width of the permanent magnet (2). The value of makes both sides of formula (5) equal.

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