Axial counter-acting adaptive vibration absorption boring bar, tool and control method
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANDONG UNIV
- Filing Date
- 2026-05-14
- Publication Date
- 2026-06-16
Smart Images
Figure CN122210091A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of boring tool vibration reduction technology, specifically relating to an axially aligned adaptive vibration-absorbing boring bar, a cutting tool, and a control method. Background Technology
[0002] In boring operations, radial vibration of the boring bar is a key factor affecting machining accuracy and workpiece surface quality, especially in deep hole boring and variable cutting depth machining. Vibration can lead to chatter marks, dimensional deviations, and even damage to the boring bar and equipment. To suppress chatter, passive damping vibration reduction technology is widely used in tool vibration reduction design due to its lack of external power requirements, simple structure, and high reliability.
[0003] Non-contact vibration reduction structures based on permanent magnets and eddy current damping have become an important technical approach for vibration reduction in long-overhanging cutting tools due to their advantages such as no friction or wear, no need for sealing, long service life, and stable damping. Existing technologies include eddy current-damped milling cutter holders employing an axially opposed permanent magnet structure. These holders use inner and outer permanent magnets opposed along the tool axis with their like poles facing each other to form a magnetic repulsion field. This magnetic repulsion supports the mass block, and the eddy current damping plates convert vibration energy into heat dissipation, which can suppress milling chatter to a certain extent. This structure allows for damping adjustment by adjusting the air gap between the magnets using axial screws, providing a feasible solution for axially opposed permanent magnet vibration reduction.
[0004] However, this type of traditional axial-aligned permanent magnet vibration damping structure still has obvious defects: the magnetic repulsion force changes nonlinearly with the air gap, and stiffness hardening is prone to occur under large amplitude, resulting in restricted mass movement, insufficient energy dissipation, and even collision failure; the damping relies on manual gap adjustment and cannot adaptively change the equivalent stiffness according to the working conditions, resulting in a narrow vibration damping frequency band and difficulty in taking into account both high-frequency low-amplitude and low-frequency high-amplitude dynamic cutting scenarios; the mass relies solely on magnetic repulsion for automatic centering, lacking flexible limiting and backup protection, resulting in insufficient stability under high speed or strong disturbance; and the structure is mostly designed for milling cutters and cannot be directly adapted to precision long overhanging tools such as boring tools.
[0005] Therefore, existing axially aligned permanent magnet vibration reduction technology is difficult to meet the high-precision vibration reduction requirements of deep hole, long overhang, and variable working condition cutting. Developing an axially aligned permanent magnet adaptive vibration absorber with equivalent stiffness self-adaptation, wide bandwidth, collision-free operation, and high energy dissipation efficiency is of great significance for improving machining accuracy and efficiency under complex working conditions. Summary of the Invention
[0006] To address the shortcomings of traditional radially stacked permanent magnet vibration absorbers in existing technologies, such as stiffness hardening, narrow vibration reduction bandwidth, insufficient energy dissipation, and poor adaptability to working conditions, as well as the limited application scenarios of external vibration absorbers, this invention provides an axially aligned adaptive vibration-absorbing boring bar, cutting tool, and control method. Through the axially aligned magnetic repulsion design, combined with the efficient dissipation characteristics of eddy current damping, the equivalent stiffness is adaptively adjusted. Under the geometric constraints of the boring tool, the vibration absorption time is extended, the vibration energy is fully dissipated, and collisions are avoided, making it suitable for boring operations under all working conditions.
[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: In a first aspect, the present invention provides an axially aligned adaptive vibration-absorbing boring bar, comprising a boring bar body, an outer magnetic ring assembly, an inner magnetic ring assembly, an elastic support element, an eddy current damping ring, and a mass block; The boring bar body has an axial cavity, and the outer magnetic ring assembly is fixed to the inner wall of the axial cavity; the inner magnetic ring assembly is fixed to the outer wall of the mass block, and the outer magnetic ring assembly and the inner magnetic ring assembly are axially aligned and form a constant magnetic repulsion field; the elastic support element is symmetrically arranged at both ends of the mass block along the axial direction for flexible limiting and bottom reset of the mass block; the eddy current damping ring is fixed to the inner wall of the axial cavity and is correspondingly arranged with the inner magnetic ring assembly for dissipating vibration energy; the inner magnetic ring assembly moves radially reciprocating with the mass block, forming a magnetic field that cuts relative to the eddy current damping ring, generating a viscous eddy current damping force proportional to the relative motion velocity.
[0008] This invention achieves wideband adaptive suppression of radial vibration of boring tools by combining the synergistic effect of axial top-to-top magnetic repulsion field and eddy current damping with the flexible limiting of elastic support elements. It is suitable for complex cutting conditions such as deep hole boring and ultra-high-speed precision boring. As a further technical solution, the outer magnetic ring assembly includes at least two outer annular permanent magnets, which are fixed at intervals along the axial direction of the boring bar body. The inner magnetic ring assembly includes inner annular permanent magnets that correspond one-to-one with the outer annular permanent magnets. The end face of the inner annular permanent magnet is directly opposite the end face of the corresponding outer annular permanent magnet, and the magnetization direction is axial, forming an axially opposing magnetic repulsive force. In the initial state, the axes of the inner annular permanent magnet and the outer annular permanent magnet are located on the same straight line.
[0009] As a further technical solution, one end of the elastic support element is fixedly connected to the mass block, and the other end is fixedly connected to the inner wall of the axial cavity of the boring bar body.
[0010] As a further technical solution, the preload of the elastic support element is adjustable, and it only plays a dominant reset role when the magnetic repulsion between the inner magnetic ring assembly and the outer magnetic ring assembly is significantly weakened.
[0011] As a further technical solution, a damping pad is provided at the connection between the elastic support element and the mass block to reduce the influence of the elastic restoring force of the elastic support element on the inherent stiffness of the system.
[0012] As a further technical solution, the eddy current damping ring is made of copper or aluminum, which are good conductors. The eddy current damping ring is sleeved between the outer magnetic ring assembly and the inner magnetic ring assembly. A radial gap of 0.1~0.3mm is left between the inner wall of the eddy current damping ring and the outer wall of the inner magnetic ring assembly. The radial gap is adapted to the radial dimension of the axial cavity of the boring bar body.
[0013] As a further technical solution, the outer wall of the mass block is interference-fitted with the inner magnetic ring assembly, and the axial length of the mass block matches the total axial length of the outer magnetic ring assembly; the mass block performs radial reciprocating motion in the same frequency and opposite direction as the radial vibration of the boring bar body, forming inertial resistance to weaken the vibration amplitude of the boring bar body.
[0014] As a further technical solution, the end face of the inner magnetic ring assembly is provided with a micro-tooth structure, and the tooth height of the micro-tooth structure is 0.01~0.02mm.
[0015] Secondly, the present invention provides a cutting tool, including the aforementioned axially aligned adaptive vibration-absorbing boring bar.
[0016] Thirdly, based on the aforementioned axially aligned adaptive vibration-absorbing boring bar, this invention provides a control method for the axially aligned adaptive vibration-absorbing boring bar, as follows: When the boring bar vibrates radially, the mass block, due to inertia, generates radial reciprocating motion in the same frequency but opposite direction as the boring bar. At small amplitudes, the effective magnetic coupling area of the inner and outer magnetic rings is large, and the magnetic repulsion force is strong, resulting in high-stiffness and rapid vibration suppression of the system. At large amplitudes, the mass block shifts outward, and the effective magnetic coupling area of the inner and outer magnetic rings decreases as the shift increases, the magnetic repulsion force decays smoothly, and the equivalent stiffness softens adaptively. At the same time, the eddy current damping automatically increases with the relative motion speed, continuously dissipating vibration energy. The elastic support element only provides a safety net for reset when the magnetic repulsion force is significantly weakened, constraining the mass block within a safe range of motion. Throughout the entire process, the system automatically achieves stiffness adjustment and energy dissipation without manual intervention, completing wide-frequency adaptive vibration reduction under all working conditions.
[0017] The beneficial effects of this invention are as follows: 1. Solving the stiffness hardening problem of traditional axially aligned permanent magnet vibration damping structures: This invention adopts an adaptive adjustment design for axially aligned magnetic repulsion. The magnetic repulsion decreases smoothly as the mass block shifts radially outward, achieving adaptive softening of the equivalent stiffness. This fundamentally avoids the "sudden braking and hardening" and stiffness hardening phenomena caused by nonlinear abrupt changes in magnetic repulsion in traditional axially aligned structures, significantly improving vibration damping stability under large amplitude vibrations and adaptively matching the requirements of cutting vibrations under varying working conditions. Alternatively, when the mass block shifts radially outward, the effective magnetic coupling area of the inner and outer magnetic rings decreases as the shift increases, and the magnetic repulsion decreases smoothly. 2. Adapting to boring tool geometric constraints: Through the flexible limiting of the elastic support element and the design of the radial clearance, the movement range of the mass block is strictly controlled within the radial clearance of the boring bar axial cavity, which not only ensures that the geometric size limit of the boring tool is not exceeded, but also achieves smooth deceleration and full energy absorption.
[0018] 3. Wideband adaptive vibration reduction: Under small amplitude, sufficient magnetic repulsion quickly suppresses high-frequency, low-amplitude vibrations; under large amplitude, the magnetic stiffness softens, the elastic support element provides a bottom-up reset, and the eddy current damping fully dissipates energy. With adaptive changes in equivalent stiffness, it can take into account all operating conditions, including low-frequency, high-amplitude and high-frequency, low-amplitude vibrations, significantly widening the vibration reduction bandwidth.
[0019] 4. Low-speed, high-efficiency energy dissipation: By selecting high-energy-product permanent magnets and low-resistivity damping rings, configuring multiple sets of magnetic rings, and designing extremely small radial gaps, the eddy current damping coefficient can be significantly improved. Combined with medium-to-high frequency reciprocating cutting, even at low relative speeds between the mass block and the boring bar, efficient energy dissipation can be achieved through the amplification effect of the damping coefficient and high-frequency cutting, solving the problem of insufficient damping dissipation at low speeds. At the same time, eddy current damping is a non-contact wear process, with advantages such as controllable damping force, fast response speed, and long service life.
[0020] 5. Convenient assembly and stable structure: This design features built-in installation without relying on external support. The design of components such as positioning pins and integrated non-metallic positioning bushings ensures the coaxiality and connection stability of the inner and outer magnetic ring assemblies. Laser coaxiality detection marks facilitate assembly calibration. Furthermore, the micro-tooth structure enhances the stability of magnetic repulsion under small amplitudes, making it suitable for all boring conditions such as deep holes, blind holes, and external cylindrical boring. It has a wide range of applications, reliable overall structure, and long service life. Attached Figure Description
[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0022] Figure 1 This is an axial sectional view of the overall structure of an embodiment of the present invention; Figure 2 This is an axial cross-sectional view of the vibration-absorbing core component in an embodiment of the present invention; Figure 3 This is an exploded view of a part according to an embodiment of the present invention; Figure 4 This is a schematic diagram illustrating the magnetic-vibration coupling and eddy current damping principle in an embodiment of the present invention; Figure 5 This is a schematic diagram illustrating the working conditions of an embodiment of the present invention.
[0023] In the figure: 1. Boring bar body, 2. Positioning pin, 3. Vibration absorption core assembly, 31. Outer magnetic ring assembly, 32. Inner magnetic ring assembly, 33. Eddy current damping tube, 34. Mass block, 4. Elastic support element, 5. Boring tool, 6. Integrated non-metallic positioning bushing, 7. Workpiece to be machined, 8. Boring machine; Detailed Implementation It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.
[0024] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, unless otherwise expressly indicated by the invention, the singular form is also intended to include the plural form. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof. For ease of description, the words "up," "down," "left," and "right" appearing in this invention only indicate that they are consistent with the up, down, left, and right directions of the accompanying drawings themselves, and do not limit the structure. They are merely for the purpose of facilitating the description of this invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.
[0025] As described in the background section, this embodiment provides an axially aligned adaptive vibration-damping boring bar, a cutting tool, and a control method. The core of this method is to achieve broadband adaptive suppression of radial vibration of the boring tool through the synergistic effect of an axially aligned magnetic repulsion field and eddy current damping, combined with the flexible limiting of an elastic support element. This adapts to complex cutting conditions such as deep hole boring and ultra-high-speed precision boring. The device includes a boring bar body, an outer magnetic ring assembly, an inner magnetic ring assembly, an elastic support element, an eddy current damping ring, and a mass block. The connection and cooperation relationship of each component is as follows: an axial cavity is opened within the boring bar body, the outer magnetic ring assembly is fixed to the inner wall of the axial cavity, and the inner magnetic ring assembly... The ring assembly is fixed to the outer wall of the mass block, so that the inner and outer magnetic ring assemblies are arranged axially opposite each other. The interaction of the axially magnetized permanent magnets forms a constant magnetic repulsion field. Elastic support elements are symmetrically set at both ends of the mass block along the axis to achieve flexible limiting of the mass block, and at the same time complete the bottom reset when the magnetic repulsion is significantly weakened. The eddy current damping ring is fixed to the inner wall of the axial cavity and radially corresponding to the inner magnetic ring assembly. When the inner magnetic ring assembly moves radially reciprocating with the mass block, it cuts relative to the magnetic field of the eddy current damping ring, converting the vibration kinetic energy of the boring bar into Joule heat in the damping ring and dissipating it naturally, thus achieving efficient dissipation of vibration energy.
[0026] To improve the stability of magnetic repulsion and avoid the stiffness hardening problem of traditional structures, the outer magnetic ring assembly is set as at least two axially spaced annular permanent magnets, and the inner magnetic ring assembly is set as one-to-one corresponding inner annular permanent magnets. The end faces of the two are facing each other and axially magnetized to form a top-to-top magnetic repulsion, and the end faces are completely overlapped in the initial state. At the same time, a high magnetic energy product permanent magnet material is selected to ensure that the overlapping area is consistent with the end face area of the inner annular permanent magnet, ensuring that the magnetic repulsion is sufficient under small amplitude and the magnetic repulsion decays smoothly under large amplitude.
[0027] Example 1 This embodiment discloses an axially aligned, self-adaptive vibration-absorbing boring bar, such as... Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 As shown, it includes a boring bar body 1, a positioning pin 2, a vibration-absorbing core assembly 3, an elastic support element 4, and an integrated non-metallic positioning bushing 6; the vibration-absorbing core assembly 3 includes an outer magnetic ring assembly 31, an inner magnetic ring assembly 32, an eddy current damping tube 33, and a mass block 34; An outer magnetic ring assembly 31 is provided at both ends of the inner ring of the eddy current damping tube 33, and a mass block 34 is provided in the middle. The mass block 34 is a symmetrical tube with the diameters at both ends being smaller than the diameter at the middle. The two inner magnetic ring assemblies 32 are fixed at both ends of the eddy current damping tube 33. The boring bar body 1 has an axial cavity inside. The integrated non-metallic positioning bushing 6 is fixed to the inner wall of the axial cavity by the positioning pin 2. It is used to realize the radial centering of the eddy current damping tube 33 and the coaxial positioning of the outer magnetic ring assembly 31. The outer magnetic ring assembly 31 includes two sets of annular permanent magnets, which are made of neodymium iron boron N52 permanent magnet material with an axial thickness of 5mm. They are arranged at intervals along the axial direction and the radial positioning and axial limiting are realized by the integrated non-metallic positioning bushing 6.
[0028] The inner magnetic ring assembly 32 and the outer magnetic ring assembly 31 correspond one-to-one, are axially magnetized, and form an axially opposing magnetic repulsion structure with their end faces facing each other. In the initial state, the axes of the inner and outer magnetic rings are located on the same straight line; such as Figure 2 As shown, the outer end of the left-side outer magnetic ring assembly 31 is the S pole and the inner end is the N pole, and the outer end of the left-side inner magnetic ring assembly 32 is the N pole and the inner end is the S pole; that is, the left-side outer magnetic ring assembly 31 and inner magnetic ring assembly 32 are mutually exclusive. The outer end of the right-side outer magnetic ring assembly 31 is the S pole and the inner end is the N pole, and the outer end of the right-side inner magnetic ring assembly 32 is the N pole and the inner end is the S pole; that is, the right-side outer magnetic ring assembly 31 and inner magnetic ring assembly 32 are mutually exclusive.
[0029] Furthermore, the outer magnetic ring assembly 31 includes at least two outer annular permanent magnets, which are fixedly spaced along the axial direction of the boring bar body; the inner magnetic ring assembly 32 includes inner annular permanent magnets that correspond one-to-one with the annular permanent magnets, the end face of the inner annular permanent magnet is directly opposite the end face of the corresponding outer annular permanent magnet, and the magnetization direction is axial, forming an axially opposing magnetic repulsive force; in the initial state, the axes of the inner annular permanent magnet and the outer annular permanent magnet are located on the same straight line.
[0030] Furthermore, the inner magnetic ring assembly 32 has a micro-tooth structure with a tooth height of 0.015 mm on its end face to improve the stability of magnetic repulsion under small amplitude. Figure 4 The diagram shows the micro-tooth structure on the end face of the inner magnetic ring assembly 32 and its axial alignment with the outer magnetic ring assembly 31. The distribution of magnetic field lines is marked, demonstrating the energy dissipation principle of the inner magnetic ring assembly 32 cutting the magnetic field with vibration and generating eddy currents inside the eddy current damping tube 33. This visually presents the core mechanism of broadband adaptive vibration reduction.
[0031] Furthermore, the inner magnetic ring assembly 32 and the mass block 34 are fixed together by an interference fit. The mass block 34 is made of high-density tungsten steel, and its axial length matches the total length of the outer magnetic ring assembly 31. The coaxiality error between the inner and outer magnetic rings is ≤0.003mm.
[0032] Furthermore, the elastic support element 4 is made of spring steel sheet, symmetrically arranged at both ends of the mass block 34. One end is fixedly connected to the mass block 34, and the other end is fixedly connected to the inner wall of the axial cavity of the boring bar body. In this embodiment, an integrated non-metallic positioning bushing 6 is fixed to the inner wall of the axial cavity of the boring bar body. Therefore, the other end of the elastic support element 4 is connected to the integrated non-metallic positioning bushing 6 to achieve flexible support and bottom reset. The elastic support element 4 only plays a dominant reset role when the magnetic repulsion force is significantly weakened, avoiding excessive interference to the adaptive adjustment of magnetic stiffness. In addition, a damping pad is added at the connection between the elastic support element and the mass block to consume the elastic potential energy of the elastic support element, weaken the influence of its elastic restoring force on the inherent stiffness of the system, and improve the overall energy dissipation efficiency.
[0033] Furthermore, the preload of the elastic support element 4 is adjustable, and it only plays a dominant reset role when the magnetic repulsion between the inner magnetic ring assembly and the outer magnetic ring assembly is significantly weakened.
[0034] Furthermore, the eddy current damping ring is made of copper or aluminum, a good conductor, with a wall thickness of 3mm. It is sleeved between the outer magnetic ring assembly and the inner magnetic ring assembly. A radial gap of 0.1~0.3mm is left between its inner wall and the outer wall of the inner magnetic ring assembly 32, which is adapted to the radial dimension of the axial cavity of the boring bar body. This radial gap avoids the collision between the mass block and the inner wall of the boring bar, while ensuring that the eddy current damping ring can effectively cut the magnetic field to achieve energy dissipation.
[0035] Furthermore, the mass block is made of high-density metal material, which is interference-fitted with the inner magnetic ring assembly and its axial length matches the total length of the outer magnetic ring assembly, ensuring connection stability and uniform magnetic repulsion. The high-density characteristics enhance inertia, causing the mass block to perform radial reciprocating motion in the same frequency but opposite direction as the boring bar's radial vibration, forming inertial resistance and directly weakening the boring bar's vibration amplitude.
[0036] Furthermore, in the design of the assembly and fixing structure, the outer magnetic ring assembly uses locating pins for positioning and fastening to adapt to the high-temperature conditions of boring machining, while the inner magnetic ring assembly is clamped and fixed with locking nuts to ensure both connection reliability and ease of assembly and disassembly. During assembly, the coaxiality deviation of the inner and outer magnetic ring assemblies must be strictly controlled. Simultaneously, laser coaxiality detection marks are pre-made on the inner wall of the axial cavity to improve assembly calibration accuracy, thereby avoiding abnormal fluctuations in magnetic repulsion force under small amplitude conditions. In addition, a micro-tooth structure with a tooth height of 0.01~0.02mm is machined on the end face of the inner magnetic ring assembly. This enhances connection stability by increasing the mechanical meshing effect during end face contact, further ensuring the stability of magnetic repulsion force output under small amplitude conditions and ensuring vibration reduction accuracy under high-frequency, low-amplitude conditions.
[0037] Furthermore, the eddy current damping force generated by the eddy current damping ring satisfies the formula: F = c·v, where F is the eddy current damping force, c is the eddy current damping coefficient, and v is the relative radial velocity between the mass block and the eddy current damping ring; the eddy current dissipation energy within a single vibration cycle satisfies the formula: W = 1 / 2·c·ω²·A²·T, where ω is the vibration angular frequency, A is the radial vibration amplitude of the mass block relative to the boring bar body, and T is the vibration period. The eddy current damping force is proportional to the relative velocity, achieving an adaptive characteristic of "the more intense the vibration, the greater the damping force, and the higher the dissipation efficiency," adapting to vibration conditions with different amplitudes; the energy dissipation formula can quantify the dissipation effect, providing theoretical support for structural parameter optimization.
[0038] Furthermore, the eddy current damping coefficient c satisfies the simplified engineering formula: c = π μ0² B² N² R³ h / (ρ In the formula, μ0 is the vacuum permeability, B is the remanence of the permanent magnet, N is the number of axially aligned magnetic rings, R is the average radius of the damping ring, h is the axial thickness of the damping ring, ρ is the resistivity of the damping ring material, and t is the radial gap between the permanent magnet and the damping ring. This formula allows for theoretical calculation and matching optimization of the damping coefficient, ensuring the system is underdamped and achieving better vibration reduction.
[0039] During operation, the boring bar body 1 is subjected to cutting force and generates radial vibration. The mass block 34 performs radial reciprocating motion in the same frequency but opposite direction due to inertia, forming inertial resistance. When the amplitude is small, the overlap area of the inner and outer magnetic rings is large, and the equivalent stiffness is high, which can quickly suppress high-frequency micro-vibrations. When the amplitude is large, the overlap area of the magnetic rings decreases, and the equivalent stiffness is adaptively softened. Combined with eddy current damping, the vibration energy is converted into heat energy dissipation, realizing wideband adaptive vibration reduction.
[0040] Specifically, in Figure 1 In the middle, the boring bar body 1 has a vibration absorption mounting cavity inside. The vibration absorption core component 3 is fixed to the inner wall of the mounting cavity by an integrated non-metallic positioning bushing 6 and a positioning pin 2. The elastic support element 4 is symmetrically arranged at both ends of the mass block 34. The boring tool 5 is installed at the front end of the boring bar, presenting a complete assembly relationship between the vibration absorber and the boring bar.
[0041] exist Figure 2 In the middle, the outer magnetic ring assembly 31 and the inner magnetic ring assembly 32 are arranged axially opposite each other to form a nonlinear permanent magnet repulsive stiffness; the inner magnetic ring assembly 32 is fixedly connected to the mass block 34, the eddy current damping tube 33 is sleeved on the outside of the inner and outer magnetic rings, and maintains a non-contact radial gap with the inner magnetic ring assembly 32; the elastic support element 4 provides flexible support, forming a complete adaptive vibration absorption system.
[0042] Furthermore, such as Figure 3 , Figure 1 As shown, this embodiment provides a tool, including a boring bar body 1 and a boring tool 5; in Figure 3 The assembly sequence and relative positions of each component are clearly shown: from the boring bar body 1 to the boring tool 5, the components are in sequence: integrated non-metallic positioning bushing 6, outer magnetic ring assembly 31, eddy current damping tube 33, inner magnetic ring assembly 32, mass block 34, elastic support element 4 and positioning pin 2, which intuitively reflects the structural form and assembly logic of each component.
[0043] exist Figure 5 In this diagram, the working condition is a deep hole boring with large overhang. The boring machine 8 in the diagram has a fixed boring tool 5, which processes the workpiece 7. This diagram visually illustrates the vibration reduction requirements under this type of machining condition and clearly demonstrates the applicable working conditions and engineering application value of this invention. The "adaptive" nature of the vibration absorber in this embodiment refers to adapting to the vibration conditions of the boring tool. It does not change the inherent stiffness of the system, but rather alters the equivalent stiffness characteristics of the system through dynamic adjustment of magnetic repulsion. All variable stiffnesses described in this invention are equivalent stiffnesses. Since the inherent stiffness of the system is a fixed value, determined by the structural parameters corresponding to the eddy current damping coefficient c, the elastic stiffness of the elastic support elements, and the magnetic stiffness of the permanent magnet, the inherent stiffness remains constant once machining and assembly are completed. The equivalent stiffness, however, can adaptively match the vibration conditions.
[0044] Specifically, the equivalent stiffness is the effective stiffness of the vibration absorber under the combined action of magnetic repulsion and elastic force during actual operation. Its magnitude varies with the radial offset of the mass block: at small amplitudes, the magnetic repulsion is sufficient, and the equivalent stiffness exhibits hard stiffness, quickly suppressing minor vibrations; at medium amplitudes, the magnetic repulsion decays steadily, and the equivalent stiffness is between soft and hard, gradually dissipating energy; at large amplitudes, the magnetic repulsion weakens significantly, and the equivalent stiffness exhibits gentle soft stiffness, avoiding hard impacts and extending the energy absorption time. Throughout the entire process, the inherent stiffness remains constant, while the dynamic performance of the equivalent stiffness changes, achieving adaptive vibration reduction under all operating conditions.
[0045] Furthermore, this embodiment also provides a control method for an axially aligned adaptive vibration-absorbing boring bar. This vibration absorber adopts a fully passive adaptive control method, requiring no external power supply, sensors, or active control module. When the boring bar vibrates radially, the mass block generates radial reciprocating motion in the same frequency and opposite direction as the boring bar due to inertia. At small amplitudes, the effective magnetic coupling area of the inner and outer magnetic rings is large, and the magnetic repulsion force is strong, resulting in high-stiffness and rapid vibration suppression of the system. At large amplitudes, the mass block shifts outward, and the effective magnetic coupling area of the inner and outer magnetic rings decreases as the shift increases, the magnetic repulsion force decays smoothly, and the equivalent stiffness softens adaptively. At the same time, the eddy current damping automatically increases with the relative motion speed, continuously dissipating vibration energy. The elastic support element only provides a safety net reset when the magnetic repulsion force is significantly weakened, constraining the mass block within a safe range of motion. The entire process automatically achieves stiffness adjustment and energy dissipation without manual intervention, completing wide-frequency adaptive vibration reduction under all working conditions.
[0046] In this embodiment, when the vibration absorber is working, with the workpiece as the stationary reference frame, when the boring bar vibrates radially under the action of cutting force, it drives the outer magnetic ring assembly and the eddy current damping ring to vibrate synchronously. Due to inertia, the mass block always tries to maintain a stationary state relative to the workpiece, and then performs radial reciprocating motion in the same frequency and opposite direction as the radial vibration of the boring bar, forming inertial resistance, weakening the vibration amplitude of the boring bar, and cutting relative to the magnetic field generated by the eddy current damping ring, converting the vibration kinetic energy into Joule heat, and realizing irreversible energy dissipation.
[0047] Under high-frequency and low-amplitude conditions, the end faces of the inner and outer magnetic ring assemblies completely overlap, and the magnetic repulsion is sufficient and stable, providing stiffness and centrifugal force to suppress minor vibrations. At the same time, the mass block and the eddy current damping ring undergo slight relative motion, generating a small amount of eddy currents, which convert some of the vibration kinetic energy into Joule heat dissipation, achieving smooth vibration reduction.
[0048] Under the transition condition, the mass block undergoes radial displacement, the overlap area between the inner and outer magnetic ring components decreases, the magnetic repulsion force is steadily attenuated, the equivalent stiffness is softened, the eddy current damping effect is enhanced, and the vibration kinetic energy is gradually dissipated. At this time, the elastic support undergoes slight deformation, providing auxiliary restoring force to ensure smooth motion and avoid excessive displacement of the mass block.
[0049] Under low-frequency, high-amplitude conditions, the overlap area between the inner and outer magnetic ring assemblies is significantly reduced, the magnetic repulsion force is significantly weakened, and the equivalent stiffness is adaptively softened as the magnetic repulsion force decays, avoiding the stiffness hardening problem of traditional structures. At this time, the elastic support element acts as the dominant reset component, providing linear restoring force and limiting the movement range of the mass block within the radial clearance of the boring bar axial cavity to avoid collisions. Simultaneously, the relative motion between the mass block and the eddy current damping ring intensifies, the relative velocity increases, and a large number of eddy currents are generated, converting a large amount of vibration kinetic energy into Joule heat dissipation, achieving full energy absorption.
[0050] Throughout the entire operation, the magnetic repulsion force is smoothly adjusted according to the change in the overlapping area, the elastic support element provides a bottom-line limit, and the eddy current damping dissipates energy. The three work together to keep the system in an underdamped state, which extends the energy absorption time without breaking the geometric space constraints of the boring bar, thus achieving broadband adaptive vibration reduction. At the same time, the vibration energy of the mass block comes entirely from the harmful vibration kinetic energy of the boring bar. With the continuous dissipation of the eddy current damping, the vibration of the boring bar gradually decays, ultimately achieving steady-state vibration reduction.
[0051] Example 2 The difference between this embodiment and Embodiment 1 is that: both the outer magnetic ring assembly 31 and the inner magnetic ring assembly 32 adopt a three-group axial arrangement structure with an axial spacing of 8mm; the eddy current damping tube 33 is made of aluminum alloy with a radial gap of 0.1mm; the preload of the elastic support element 4 is 3N; the tooth height of the micro-tooth structure on the end face of the inner magnetic ring is 0.01mm; and the coaxiality error of the inner and outer magnetic rings is ≤0.005mm.
[0052] This embodiment features faster damping response and higher vibration reduction accuracy with small amplitude, making it suitable for high-speed precision boring machining.
[0053] Example 3 The difference between this embodiment and embodiment 1 is that: the radial gap between the inner magnetic ring assembly 32 and the eddy current damping tube 33 is set to 0.3mm; the preload of the elastic support element 4 is 7N; the tooth height of the micro-tooth structure on the end face of the inner magnetic ring is 0.02mm; the mass block 34 is made of high-density stainless steel; and the wall thickness of the eddy current damping tube 33 is 5mm.
[0054] This embodiment offers enhanced reset stability and is suitable for suppressing low-frequency, large-amplitude vibrations during deep hole boring.
[0055] Finally, it should be noted that relational terms such as first and second are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations.
[0056] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. An axially aligned, self-adaptive vibration-absorbing boring bar, characterized in that, It includes the boring bar body, outer magnetic ring assembly, inner magnetic ring assembly, elastic support element, eddy current damping ring, and mass block; The boring bar body has an axial cavity, and the outer magnetic ring assembly is fixed to the inner wall of the axial cavity; the inner magnetic ring assembly is fixed to the outer wall of the mass block, and the outer magnetic ring assembly and the inner magnetic ring assembly are axially aligned and form a constant magnetic repulsion field; the elastic support element is symmetrically arranged at both ends of the mass block along the axial direction for flexible limiting and bottom reset of the mass block; the eddy current damping ring is fixed to the inner wall of the axial cavity and is correspondingly arranged with the inner magnetic ring assembly for dissipating vibration energy; the inner magnetic ring assembly moves radially reciprocating with the mass block, forming a magnetic field that cuts relative to the eddy current damping ring, generating a viscous eddy current damping force proportional to the relative motion velocity.
2. The axially aligned adaptive vibration-absorbing boring bar according to claim 1, characterized in that, The outer magnetic ring assembly includes at least two outer annular permanent magnets, which are fixed at intervals along the axial direction of the boring bar body. The inner magnetic ring assembly includes inner annular permanent magnets that correspond one-to-one with the outer annular permanent magnets. The end face of the inner annular permanent magnet is directly opposite the end face of the corresponding outer annular permanent magnet, and the magnetization direction is axial, forming an axially opposing magnetic repulsive force. In the initial state, the axes of the inner annular permanent magnet and the outer annular permanent magnet are located on the same straight line.
3. The axially aligned adaptive vibration-absorbing boring bar according to claim 1, characterized in that, One end of the elastic support element is fixedly connected to the mass block, and the other end is fixedly connected to the inner wall of the axial cavity of the boring bar body.
4. The axially aligned adaptive vibration-absorbing boring bar according to claim 3, characterized in that, The preload of the elastic support element is adjustable, and it plays a dominant reset role only when the magnetic repulsion between the inner magnetic ring assembly and the outer magnetic ring assembly is significantly weakened.
5. The axially aligned adaptive vibration-absorbing boring bar according to claim 3, characterized in that, The connection between the elastic support element and the mass block is provided with a damping pad to reduce the influence of the elastic restoring force of the elastic support element on the inherent stiffness of the system.
6. The axially aligned adaptive vibration-absorbing boring bar according to claim 1, characterized in that, The eddy current damping ring is made of copper or aluminum, a good conductor. The eddy current damping ring is sleeved between the outer magnetic ring assembly and the inner magnetic ring assembly. A radial gap of 0.1~0.3mm is left between the inner wall of the eddy current damping ring and the outer wall of the inner magnetic ring assembly. The radial gap is adapted to the radial dimension of the axial cavity of the boring bar body.
7. The axially aligned adaptive vibration-absorbing boring bar according to claim 1, characterized in that, The outer wall of the mass block is interference-fitted with the inner magnetic ring assembly, and the axial length of the mass block matches the total axial length of the outer magnetic ring assembly. The mass block reciprocates radially in the same frequency but opposite direction as the boring bar body, forming inertial resistance to weaken the vibration amplitude of the boring bar body.
8. The axially aligned adaptive vibration-absorbing boring bar according to claim 1, characterized in that, The end face of the inner magnetic ring assembly is provided with a micro-tooth structure, and the tooth height of the micro-tooth structure is 0.01~0.02mm.
9. A cutting tool, characterized in that, Includes the axially aligned adaptive vibration-absorbing boring bar as described in any one of claims 1-8.
10. The control method for an axially aligned adaptive vibration-absorbing boring bar as described in any one of claims 1-8, characterized in that, When the boring bar vibrates radially, the mass block, due to inertia, generates radial reciprocating motion in the same frequency but opposite direction as the boring bar. At small amplitudes, the outer and inner magnetic ring assemblies have large effective magnetic coupling areas and strong magnetic repulsion, resulting in a high-stiffness and rapid vibration suppression of the system. At large amplitudes, the mass block shifts outwards, and the effective magnetic coupling areas of the outer and inner magnetic ring assemblies decrease as the shift increases, the magnetic repulsion decreases smoothly, and the equivalent stiffness softens adaptively. At the same time, the eddy current damping automatically increases with the relative motion speed, continuously dissipating vibration energy. The elastic support element provides a safety net for resetting when the magnetic repulsion weakens significantly, confining the mass block within a safe range of motion.