A boring bar adapter with support stiffness semi-active control

Abstract

The application discloses a boring bar adapter with semi-active control of support rigidity, which comprises an adapter, a boring bar, a baffle, an electromagnet, a copper column, a magnet, a rubber ring, a support part, a shell, a sleeve, a control unit and an acceleration sensor; the boring bar is inserted into the adapter and fixed, and a cavity is formed at the root of the boring bar through the baffle and the shell; the electromagnet is arranged in the cavity, and an axial gap exists between the electromagnet and the magnet; the interaction force between the electromagnet and the magnet is controlled through the control unit; the other end is the rubber ring, which is placed in the space formed between the rubber ring base and the shell; the force received by the magnet is transmitted through the sleeve to extrude the rubber ring, change the support rigidity of the rubber ring and further change the rigidity of the boring bar; the acceleration sensor is arranged on the rubber end side, and the current size is adjusted through the control unit to change the pressure condition of the rubber ring, so that the change of the support rigidity of the boring bar is realized. The application is used for deep hole machining.

Description

Technical Field

[0001] This invention relates to a novel boring bar adapter with semi-active control of support stiffness, belonging to the field of metal cutting technology. Background Technology

[0002] In the field of mechanical manufacturing, boring is a material removal and forming method in metal forming processes. Boring accounts for about one-third of metal cutting and is widely used in precision machinery, instrumentation, and aerospace. Boring is commonly used for machining deep holes in parts. Drilling and boring are currently the main methods of hole machining. Compared with drilling, boring has advantages such as wider adaptability, higher machining efficiency, higher machining quality, and easier chip removal.

[0003] Boring is one of the main methods for deep hole machining. Boring vibration is the oscillation generated between the workpiece and the machining tool during metal removal, also known as self-excited vibration. In deep hole boring, the boring bar is suspended deep inside the workpiece, and its suspension time is long with a large elongation, resulting in low stiffness. This makes the boring bar prone to vibration during boring. Under certain conditions, chatter can also occur during the cutting process, significantly affecting the stability of the cutting process. Vibration during cutting is a crucial factor affecting the surface finish; it severely impacts the accuracy and efficiency of boring, increases tool wear, and shortens the machine tool's lifespan. Summary of the Invention

[0004] In response to the aforementioned existing technology, and in order to solve the problem that the long overhang tool bar vibrates greatly during the machining process, thus affecting the machining efficiency and the surface quality, this invention designs an adapter for the boring bar.

[0005] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0006] A novel boring bar adapter with semi-active support stiffness control includes a boring bar, an electromagnet, a magnet, a rubber ring, a sleeve, and a base. The rear end of the boring bar is inserted into the adapter, and a baffle is fixed to the adapter. The baffle and the outer shell are connected by a copper pillar to form a cavity that encloses the boring bar in the middle. A cavity is formed at the root of the boring bar, and an inner sleeve is placed inside. The electromagnet is placed at the rear end of the cavity and fixed to the baffle. The magnet is fixed to the magnet base and placed at the front end of the electromagnet. A limiting ring is placed between the magnet base and the electromagnet. The rubber ring base is placed at the front end of the cavity and contacts the inner sleeve. The rear end of the outer sleeve contacts the magnet base, and a small space is formed between the front end and the rubber ring base to place the rubber ring.

[0007] Furthermore, the adapter is equipped with a clamping system that clamps the boring bar by tightening countersunk screws.

[0008] Furthermore, the bottom of the electromagnet, the baffle, and the clamp are fixed together by countersunk screws.

[0009] Furthermore, the rear end of the copper column contacts the baffle and the two are connected by countersunk screws, while the front end of the copper column is connected to the outer shell and fixed by nuts.

[0010] Furthermore, the built-in sleeve is inserted into the electromagnet and connects to the front end of the baffle. The front end of the built-in sleeve is connected to the rubber ring base, and the surface of the built-in sleeve is smooth.

[0011] Furthermore, the rubber ring base is fixed to the boring bar by a set screw.

[0012] Furthermore, the sleeve, base, and outer shell are made of a non-magnetic material.

[0013] Furthermore, an acceleration sensor is provided on the outer wall of the boring bar body located on one side of the rubber ring;

[0014] Furthermore, the accelerometer and the electromagnet are connected to the intelligent control unit;

[0015] Furthermore, the intelligent control unit includes a central processing unit, an acceleration signal acquisition card, and a DC electromagnet current controller. The central processing unit includes a stiffness control program that analyzes the signal from the acceleration sensor, extracts the current excitation frequency, obtains the minimum stiffness at the current excitation frequency based on the excitation frequency-vibration amplitude function of the single-degree-of-freedom system dynamics model, and adjusts the current of the electromagnet to adjust the support stiffness to the minimum stiffness at the current excitation frequency.

[0016] The beneficial effects of this invention compared to the prior art are:

[0017] This invention provides a novel boring bar adapter with semi-active control of support stiffness. It generates magnetic force through an electromagnet, which repels a magnet. The repulsive force on the magnet is transferred to a rubber ring through an external sleeve. The rubber ring is compressed and deformed, causing the stiffness of the supporting cantilever beam to change during boring, thereby achieving the purpose of boring bar vibration reduction, thus improving the machining accuracy of the workpiece and the machining efficiency of the boring machine.

[0018] This invention controls the stiffness of the oscillator by changing the cantilever length of the cantilever rod, which is more adjustable than using rubber alone to provide stiffness; it adopts the principle of magnetic levitation, which is less prone to leakage, easier to install, more controllable, and more responsive than products using magnetorheological fluids.

[0019] This invention employs an intelligent control module to process and analyze the collected acceleration signals in real time. It obtains the optimal stiffness through internally stored correspondences and controls the actuator to achieve adaptive adjustment under different working conditions without human intervention. Attached Figure Description

[0020] Figure 1 A schematic diagram of the overall structure of the vibration-damping boring bar described in this invention.

[0021] Figure 2 yes Figure 1 The sectional view in the image.

[0022] Figure 3 yes Figure 1 Schematic diagram of the adapter structure.

[0023] Figure 4 yes Figure 3 The sectional view of BB in the image.

[0024] Figure 5 yes Figure 1 Enlarged view of a portion of the rubber ring base. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the scope of the invention.

[0027] Detailed implementation method: The following is a combination of... Figures 1 to 5 This embodiment describes a novel electromagnetic active control vibration damping boring bar, comprising an adapter 1, a boring bar body 2, a boring blade 3, a rubber ring 4, a rubber ring base 5, a housing 6, a magnet base 7, a magnet 8, an internal sleeve 9, an electromagnet 10, a limit ring 11, an external sleeve 12, a baffle 13, a copper column 14, a set screw 15, a nut 16, countersunk screws 17-19, a control unit 20, and an acceleration sensor 21.

[0028] The boring bar body is inserted into the adapter 1 and tightened by the countersunk screw 19. The boring tool 3 is finally installed on the boring bar body 2. The electromagnet 10 and the baffle 13 are fixed to the fixture by the countersunk screw 17. The inner sleeve 9 is inserted so that the bottom contacts the baffle 13. The magnet 8 is fixed to the magnet base 7. The limiting ring 11 and the magnet base 7 are put on the inner sleeve 9 so that the magnet 8 and the electromagnet 10 are opposite each other. The outer sleeve 12 is put on so that the outer sleeve 12 contacts the magnet base 7. The rubber ring base 5 is put on the boring bar body 2 so that the top of the rubber ring base 5 contacts the inner sleeve 9 and is fixed to the boring bar body 2 by the set screw 15. The root of the copper column 14 is fixed to the baffle 13 by the countersunk screw 18. The outer shell 6 and the top of the copper column 14 are connected by the nut 16.

[0029] In this embodiment, the electromagnet 10 is connected to the control unit 20. The control system provides power and control to the electromagnet 10. When the control unit 20 outputs current to the electromagnet 10, the electromagnet 10 generates magnetic force. The magnitude of the magnetic force determines the magnitude of the output current. The magnetic field generated by the magnet 8 and the electromagnet 10 is opposite to each other. The magnetic repulsion force is transmitted to the magnet 8 opposite to the electromagnet 10. The magnet 8 squeezes the rubber ring 4 through the outer sleeve 12 that contacts the magnet base 7.

[0030] In this embodiment, an acceleration sensor 21 is provided on the outer wall of the boring bar body 2, located on one side of the rubber ring 4.

[0031] In this embodiment, the accelerometer 21 and the electromagnet 10 are both connected to the control unit 20; the control unit 20, the electromagnet 10, and the accelerometer 21 constitute a control loop of sensor, controller, and actuator.

[0032] The control unit 20 includes a controllable voltage power supply for controlling the electromagnet 10, a central processing unit that can be controlled via Wi-Fi, and integrates an acceleration signal acquisition card and a DC electromagnet current controller. It can collect and process the signal from the acceleration sensor 21 through a charge amplifier and automatically calculate and output corresponding parameters to control the electromagnet 10.

[0033] The central processing unit includes a stiffness control program. By analyzing the signal from the accelerometer 21, it extracts the current excitation frequency. Based on the excitation frequency-vibration amplitude function of the single-degree-of-freedom system dynamics model, it obtains the minimum stiffness that enables the vibration amplitude at the current excitation frequency. By adjusting the current of the electromagnet 5, it changes the support stiffness of the rubber ring 4, thereby adjusting the stiffness of the boring bar body 2 to this value (i.e., the minimum stiffness that enables the vibration amplitude at the current excitation frequency obtained above).

[0034] During boring, the boring bar will vibrate. At this time, the rubber ring 4 will act as a damping ring at the root of the boring bar. The support stiffness of the boring bar will change, thereby reducing the vibration. The boring bar achieves the purpose of vibration reduction.

[0035] In this embodiment, the outer sleeve 12 and the magnet base 7 are in close contact, the magnet base 7, the outer sleeve 12 and the inner sleeve 9 are slidably connected, and the inner sleeve 12 and the electromagnet 10 are in transitional fit.

[0036] The working process of the vibration damping boring bar adapter of the present invention is as follows:

[0037] Step 1: Install the boring bar and boring bar adapter on the boring machine. After setting the speed, depth of cut and feed rate, perform boring on the workpiece by rotating the workpiece, feeding the boring bar and multiple passes.

[0038] Step 2: Accelerometer 21 detects acceleration signals in real time and sends the detected acceleration signals to control unit 20.

[0039] Step 3: When the acquired vibration acceleration signal stabilizes, analyze and extract its frequency domain characteristics to obtain the current vibration frequency;

[0040] Step 4: Based on the excitation frequency-vibration amplitude function of the single-degree-of-freedom system dynamic model, obtain the stiffness that minimizes the vibration amplitude of the boring bar at the current excitation frequency, and adjust the stiffness to this value by adjusting the current of electromagnet 10.

[0041] Step 5: While the tool is moving, the stiffness is adjusted. The electromagnet 10 is affected by the change in current, which in turn changes the magnetic field strength and the electromagnetic force on the magnet 8. This causes the extrusion force transmitted to the rubber ring 4 through the external sleeve 12 to change. Due to the deformation of the rubber ring 4 under the force, the support stiffness of the boring bar body 2 changes, thereby achieving vibration reduction of the boring bar body 2 under the current working condition.

[0042] Step 6: When the processing parameters change, the system automatically repeats the above process to complete real-time optimal vibration reduction control.

[0043] 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 exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. 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.

[0044] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0045] 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. A boring bar adapter for semi-active control of support stiffness, characterized in that, Includes adapter (1), boring bar body (2), boring blade (3), rubber ring (4), rubber ring base (5), housing (6), magnet base (7), magnet (8), built-in sleeve (9), electromagnet (10), limit ring (11), external sleeve (12), baffle (13), copper column (14), control unit (20), and acceleration sensor (21); The adapter (1) clamps and fixes the root of the boring bar body (2), fixes the boring tool (3) on the boring bar body (2), inserts the inner sleeve (9) so that the bottom of the inner sleeve (9) contacts one side of the baffle (13), and the other side of the baffle (13) is connected to the adapter (1); the baffle (13) and the outer shell (6) are connected by the copper pillar (14) to form a cavity, and the magnet base (7) is placed in it. The magnet (8) is fixed on the magnet base (7), and a limiting ring (11) is placed between the magnet base (7) and the electromagnet (10); the outer sleeve (12) is connected to the magnet base (7), the rubber ring base (5) is fixed on the boring bar body (2), and the rubber ring (4) is placed at the bottom of the rubber ring. On the seat (5); the bottom of the electromagnet (10) and the baffle (13) are fixed to the adapter (1) by countersunk screws; the current in the electromagnet (10) is changed by the control unit (20), so that the magnet (8) is subjected to different magnitudes of magnetic repulsion force, which is transmitted through the external sleeve (12) to squeeze the rubber ring (4), so that the stiffness of the boring bar is changed; the acceleration sensor (21) is placed on one side of the rubber ring (4) and connected to the control unit (20); during boring, the boring bar will vibrate. At this time, the rubber ring (4) will act as a damping ring at the root of the boring bar, and the support stiffness of the boring bar will change, thereby reducing the vibration and achieving the purpose of vibration reduction.

2. The boring bar adapter with semi-active control of support stiffness according to claim 1, characterized in that, The adapter (1) has a clamping system that clamps the boring bar body (2).

3. The boring bar adapter with semi-active control of support stiffness according to claim 1, characterized in that, The rubber ring base (5) is positioned and fixed on the boring bar body (2) by a set screw.

4. The boring bar adapter with semi-active control of support stiffness according to claim 1, characterized in that, The position of the components in the cavity is restricted by the rubber seat and adapter (1).

5. A boring bar adapter with semi-active control of support stiffness according to claim 1, characterized in that, The specific process of stiffness adjustment is as follows: Step 1: Install the boring bar and boring bar adapter on the boring machine, and set the speed, depth of cut, and feed rate; Step 2: The accelerometer (21) detects the acceleration signal in real time and sends the detected acceleration signal to the control unit (20). Step 3: Once the acquired vibration acceleration signal stabilizes, analyze and extract its frequency domain characteristics. Obtain the current vibration frequency; Step 4: Based on the excitation frequency-vibration amplitude function of the single-degree-of-freedom system dynamic model, obtain the stiffness that minimizes the vibration amplitude of the boring bar at the current excitation frequency, and adjust the stiffness to this value by adjusting the current of the electromagnet (10). Step 5: Automatically repeat when processing parameters change to achieve real-time optimal vibration reduction control.

6. A boring bar adapter with semi-active control of support stiffness according to claim 1, characterized in that, The control unit (20) includes a controllable voltage power supply for controlling the electromagnet (10), a central processing unit controlled by Wifi, and an integrated acceleration signal acquisition card and a DC electromagnet current controller. It can collect and process the signal from the acceleration sensor (21) through a charge amplifier and automatically calculate and output the corresponding parameters to control the electromagnet (10).

7. A boring bar adapter with semi-active control of support stiffness according to claim 6, characterized in that, The central processing unit includes a stiffness control program. By analyzing the signal from the accelerometer (21), the current excitation frequency is extracted. Based on the excitation frequency-vibration amplitude function of the single-degree-of-freedom system dynamics model, the stiffness that minimizes the vibration amplitude at the current excitation frequency is obtained. By adjusting the current of the electromagnet (10), the support stiffness of the rubber ring (4) is changed, so that the stiffness of the boring bar body (2) is adjusted to the value that minimizes the vibration amplitude at the current excitation frequency obtained above.

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