A variable mass and variable damping vibration damping boring bar

Abstract

A variable-mass and variable-damping vibration-damping boring bar belongs to the field of machining. In order to solve the problem of how to reduce the vibration frequency of the boring bar to improve the machining accuracy of the workpiece surface. The present invention includes a boring bar body and a mass block. An installation cavity is axially opened in the boring bar body. The cutting tool head is detachably connected to the boring bar body and seals the installation cavity. The mass block is installed in the installation cavity through a cantilever beam and is arranged close to the cutting tool head side. The mass block is suspended in the installation cavity of the boring bar body to generate reverse vibration with the boring bar body. A cavity is axially opened in the mass block, and a fluid is injected into the cavity. The fluid is injected into the cavity or pumped out of the cavity through a pipeline, so as to change the mass of the mass block and realize the adjustment of the vibration frequency and vibration amplitude of the mass block. The present invention is mainly used for deep hole machining of workpieces.

Description

Technical Field

[0001] The present invention belongs to the field of machining, and particularly relates to a vibration-damping boring bar with variable mass and variable damping. Background Art

[0002] Boring machining is an important method for machining parts in the machinery manufacturing industry, and is widely used in fields such as aerospace, precision machinery, instrumentation, and automobile manufacturing. The precision of parts directly affects their service performance and lifespan.

[0003] Boring bars are widely used in deep-hole machining. However, due to the low stiffness of their cantilever beam structure, when the ratio of the length to the diameter of the boring bar is relatively large, vibration problems often occur, resulting in a decrease in the machining surface quality of the workpiece. Existing vibration-damping boring bars generally have a cavity inside the boring bar and a mass block is placed inside. Both ends of the mass block are respectively connected to the inner wall of the cavity through a cantilever beam. During deep-hole machining, the cutting tool transmits vibrations to both the boring bar body and the mass block. Both the boring bar body and the mass block vibrate radially. Under the action of inertia, the vibration directions of the boring bar body and the mass block are opposite. Therefore, the design of the mass block can weaken the amplitude and frequency of the vibration of the boring bar body and improve the machining quality of the workpiece surface. However, since the vibration of the boring bar during machining is related to the machining parameters and the material of the workpiece to be machined; when the material of the workpiece to be machined is determined, the vibration of the boring bar body changes with the change of the machining parameters. Then, the vibration of the mass block also needs to change so as to reduce the vibration frequency and amplitude of the boring bar body and improve the machining precision of the workpiece surface. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides a vibration-damping boring bar with variable mass and variable damping; by adjusting the mass of the mass block and the damping effect of the damping adjustment unit, the vibration frequency of the boring bar body is changed to improve the machining precision.

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

[0006] A variable-mass and variable-damping vibration-damping boring bar, comprising a boring bar body, a mass block, a cantilever beam, a cutting head, an acceleration sensor and a control module. An open cavity is formed at the front end of the boring bar body along the axial direction of its central axis. The cutting head is installed at the front end of the boring bar body through a cutting head connecting piece, and the open cavity is sealed to form an installation cavity. The mass block is axially installed in the installation cavity of the boring bar body through the cantilever beams at both ends and is arranged close to the cutting head side. The mass block is suspended in the installation cavity to generate reverse vibration with the boring bar body. The acceleration sensor is installed at one end of the boring bar body close to the cutting head and is used to measure the vibration frequency of the boring bar body. The control module is arranged outside the boring bar body and is electrically connected to the acceleration sensor. It is characterized in that: a cavity is formed in the mass block, and a fluid is injected into the cavity. By adjusting the volume of the fluid, the mass of the mass block is changed, and thus the vibration frequency of the boring bar body is adjusted.

[0007] Preferably, the vibration-damping boring bar further comprises a fluid adjustment unit. The fluid adjustment unit is arranged in the installation cavity of the boring bar body and is set on the side far from the cutting head. The fluid adjustment unit is communicated with the cavity in the mass block to adjust the volume of the fluid in the cavity.

[0008] Preferably, the fluid adjustment unit is of a piston-type electric cylinder structure, which comprises a cylinder body, a piston and a micro electric push rod. The cylinder body is fixedly installed in the installation cavity. The piston is slidably installed in the inner cavity of the cylinder body and divides the inner cavity of the cylinder body into a liquid storage cavity and a gas cavity. The liquid storage cavity is communicated with the cavity of the mass block through a liquid inlet and outlet pipe to adjust the volume of the fluid in the mass block. The gas cavity is communicated with the cavity of the mass block through an air pipe to press out the fluid. The micro electric push rod is arranged in the gas cavity of the cylinder body. The telescopic end of the micro electric push rod is fixedly connected with the piston to adjust the position of the piston in the cylinder body. The control module is electrically connected to the micro electric push rod to realize the start and stop of the micro electric push rod.

[0009] Preferably, the gas cavity is communicated with the outside atmosphere.

[0010] Preferably, the fluid injected into the mass block is a high-density liquid and / or a high-viscosity liquid.

[0011] Preferably, a plurality of magnetic ring units are coaxially installed in the cavity of the mass block. The inner ring walls of the plurality of magnetic ring units and the end faces at both ends of the mass block form a fluid accommodation cavity, and a magnetorheological fluid is injected. Each magnetic ring unit comprises an annular sleeve and a plurality of electromagnetic coil mounting seats. The plurality of electromagnetic coil mounting seats are circumferentially and uniformly installed on the inner wall of the annular sleeve. An electromagnetic coil is wound on each electromagnetic coil mounting seat, and the axial direction of the electromagnetic coil is the same as the radial direction of the mass block.

[0012] Preferably, at least one end of the mass block is connected to the installation cavity of the boring bar body through a damping adjustment unit to produce a damping effect on the vibration of the mass block; the damping adjustment unit includes a connecting sleeve, a capsule-shaped airbag, and an airbag fixing bracket arranged axially in sequence; one end of the connecting sleeve is detachably connected to the end of the cantilever beam away from the mass block, the other end of the connecting sleeve is sleeved on one end of the capsule-shaped airbag, and the other end of the capsule-shaped airbag is fixed in the installation cavity in the boring bar body through the airbag fixing bracket, and the damping force is changed by adjusting the air pressure of the capsule-shaped airbag.

[0013] Preferably, the connecting sleeve is trumpet-shaped, the flared end of the connecting sleeve is sleeved on the end of the capsule-shaped airbag and produces mutual extrusion, and the narrow end of the connecting sleeve is connected to the cantilever beam.

[0014] Preferably, the connecting sleeve is a rigid member.

[0015] Preferably, the connecting sleeve is an elastic member.

[0016] The beneficial effects of the present invention compared with the prior art are as follows:

[0017] 1. The mass block of the present application adopts a cavity structure and can adjust the mass. The control module calculates and solves the optimal mass required by the mass block through a model, and then injects or extracts fluid into the cavity of the mass block to make the mass block reach the optimal mass. At this time, the vibration frequency of the mass block changes, and under the action of the mass block, the vibration frequency and amplitude of the boring bar body are the smallest, improving the machining accuracy of the workpiece surface.

[0018] 2. The present application is provided with a fluid adjustment unit. On the one hand, the fluid adjustment unit is connected to the cavity of the mass block and forms a closed-loop path to change the mass of the mass block; on the other hand, the fluid adjustment unit is arranged in the boring bar body to ensure that no matter how the mass of the mass block changes, the mass of the boring bar body is constant, so it will not affect the natural frequency of the boring bar body. When the natural frequency of the boring bar body is constant, the optimal mass of the mass block can be accurately measured to achieve precise adjustment.

[0019] 3. The fluid adjustment unit of the present application is a piston-type electric cylinder structure. The cavity of the mass block communicates with the outside atmosphere through the air cavity in the fluid adjustment unit to ensure that the fluid in the mass block can flow out smoothly. At the same time, it avoids the problem of air leakage in the cavities on both sides of the cylinder body caused by excessive pressure in the fluid adjustment unit, so that the purpose of fluid adjustment cannot be achieved.

[0020] 4. When the fluid in the mass of this application is a high-density liquid, it can accelerate the adjustment of the vibration frequency and amplitude of the mass; when the fluid is a high-viscosity liquid, the adhesion between the high-viscosity liquid and the inner wall of the mass is relatively strong, and it can vibrate synchronously with the mass, so the influence on the vibration frequency of the mass is relatively small; when the fluid is a magnetorheological fluid, the magnetorheological fluid instantaneously becomes a solid-like state under the action of a magnetic field, and can vibrate synchronously with the mass, avoiding the reverse vibration of the fluid from affecting the adjustment of the vibration frequency and amplitude of the mass, and realizing precise adjustment.

[0021] 5. This application is also provided with a damping adjustment unit. The damping adjustment unit not only has damping for the up and down vibration of the mass, but also has frictional damping, and the damping effect is achieved by consuming the energy of vibration through friction; in addition, the connecting sleeve can be made of an elastic member. The flared end of the connecting sleeve is further expanded under the extrusion of the capsule-shaped airbag, the included angle between the barrel wall of the connecting sleeve and the outer surface of the capsule-shaped airbag becomes larger, the normal pressure of sliding friction becomes larger, and the contact area between the two is larger, and the frictional damping effect is better. Brief Description of the Drawings

[0022] The drawings, as part of this application, are used to provide a further understanding of the present invention.

[0023] Figure 1 It is a schematic diagram of the external structure of the present invention.

[0024] Figure 2 It is a schematic diagram of the internal structure of the present invention.

[0025] Figure 3 It is Figure 2 The partial enlarged view of part A in

[0026] Figure 4 It is a schematic diagram of the structure of the capsule-shaped airbag.

[0027] Figure 5 It is a schematic diagram of the structure of the connecting sleeve.

[0028] Figure 6 It is a schematic diagram of the internal structure of the vibration damping boring bar when the fluid adopts a magnetorheological liquid.

[0029] Figure 7 It is Figure 6 The partial enlarged view of part B in

[0030] Figure 8 It is a schematic diagram of the structure of the magnetic ring unit.

[0031] Description of the reference numerals: boring bar body 1; installation cavity 11; through hole 12; mass block 2; cavity 21; cantilever beam 3; cutter head 4; acceleration sensor 5; control module 6; fluid regulating unit 7; cylinder block 71; liquid storage cavity 711; air cavity 712; piston 72; micro electric push rod 73; liquid inlet and outlet pipe 74; air pipe 75; air vent cavity 76; damping regulating unit 8; connecting sleeve 81; capsule-shaped airbag 82; airbag fixing bracket 83; magnetic ring unit 9; annular sleeve 91; electromagnetic coil mounting seat 92; electromagnetic coil 93. Specific embodiments

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. The following embodiments are used to illustrate the present invention but are not used to limit the scope of the present invention.

[0033] As Figure 1 and Figure 2 shown, an embodiment of the present application provides a variable mass and variable damping vibration reduction boring bar, including a boring bar body 1 and a mass block 2. An open cavity and a through hole 12 penetrating the open cavity are successively formed in the boring bar body 1 along the axial direction. The cutter head 4 is detachably connected to the front end of the boring bar body 1 through a cutter head connecting piece and seals the open cavity to form an installation cavity 11. One cantilever beam 3 is arranged at each end of the mass block 2. One end of the mass block 2 is connected to the cutter head 4 through the cantilever beam 3, and the other end is connected to the inner wall of the installation cavity 11 through the cantilever beam 3. The mass block 2 is arranged close to the cutter head 4 side and is suspended in the installation cavity 11 of the boring bar body 1 to generate reverse vibration with the boring bar body 1. A cavity 21 is formed in the mass block 2 along the axial direction. A fluid is injected into the cavity 21. The fluid is injected into the cavity 21 or pumped out of the cavity 21 through a pipeline, so as to change the mass of the mass block 2 and realize the adjustment of the vibration frequency and vibration amplitude of the mass block 2.

[0034] In this embodiment, the damping boring bar further includes an acceleration sensor 5 and a control module 6. The signal output end of the acceleration sensor 5 is connected to the signal input end of the control module 6. The acceleration sensor 5 is installed on the boring bar body 1 and close to the tool head 4 to measure the vibration frequency of the tool head 4. Before machining the workpiece, parameters such as the rotational speed, cutting depth, and feed rate of the boring bar are input into the control module 6. During the machining of the workpiece, the tool head 4 transmits vibrations to the boring bar body 1 and the mass block 2. The acceleration sensor 5 measures the vibration signal at the tool head 4 and transmits it to the control module 6. The control module 6 analyzes the vibration frequency of the tool head 4 through these signals, and then inputs the vibration frequency of the tool head 4 into the model established by the control module 6. At this time, the boring bar body 1 and the mass block 2 are at a constant natural frequency. The control module 6 calculates and solves for the optimal mass required for the mass block 2 through the model, and then injects fluid into or extracts fluid from the cavity 21 of the mass block 2 through a pipeline to make the mass block 2 reach the optimal mass. At this time, the vibration frequency of the mass block 2 changes, and under the action of the mass block 2, the vibration frequency and amplitude of the boring bar body 1 are minimized, improving the machining accuracy of the workpiece surface.

[0035] Further, when parameters such as the material, rotational speed, cutting depth, and feed rate of the workpiece are determined, the vibration frequency of the tool head 4 basically does not change. The tool head 4 transmits this vibration to the boring bar body 1 and the mass block 2. Since the natural frequencies of the boring bar body 1 and the mass block 2 are related to the mass and vibration amplitude, to change the vibration frequency and amplitude of the boring bar body 1 by changing the mass of the mass block 2, after measuring the vibration frequency of the tool head 4 through the acceleration sensor 5, the natural frequency of the boring bar body 1 needs to be fixed. However, the mass block 2 is installed inside the boring bar body 1. When the mass of the mass block 2 changes, the mass of the boring bar body 1 will also inevitably change, and the natural frequency of the boring bar body 1 will also change accordingly. That is to say, when the mass of the boring bar body 1 changes, the optimal mass of the mass block 2 cannot be obtained through calculation. As Figure 2 and Figure 3 shown, the damping boring bar further includes a fluid adjustment unit 7. The fluid adjustment unit 7 is arranged inside the installation cavity 11 of the boring bar body 1 and on the side far from the tool head 4. The fluid adjustment unit 7 is connected to the cavity 21 inside the mass block 2 to form a closed-loop path, extracting the fluid inside the mass block 2 to the fluid adjustment unit 7, or injecting the fluid in the fluid adjustment unit 7 into the mass block 2 to ensure that no matter how the mass of the mass block 2 changes, the mass of the boring bar body 1 is constant, so it will not affect the natural frequency of the boring bar body 1. When the natural frequency of the boring bar body 1 is constant, the optimal mass of the mass block 2 can be accurately measured to achieve precise adjustment.

[0036] Among them, as Figure 2As shown in the figure, the fluid regulation unit 7 is a piston-type electric cylinder structure, which includes a cylinder block 71, a piston 72 and a micro electric push rod 73; the cylinder block 71 is fixedly installed in the installation cavity 11, and there is a ventilation cavity 76 between the cylinder block 71 and the side wall surface of the installation cavity 11 close to the through hole 12. The ventilation cavity 76 is communicated with the through hole 12 and is communicated with the outside atmosphere through the through hole 12; the piston 72 is slidably installed in the inner cavity of the cylinder block 71 and divides the inner cavity of the cylinder block 71 into a liquid storage cavity 711 and a gas cavity 712; the liquid storage cavity 711 is communicated with the cavity 21 of the mass block 2 through a liquid inlet and outlet pipe 74 to adjust the volume of the fluid in the mass block 2; the gas cavity 712 is communicated with the ventilation cavity 76 and is communicated with the cavity 21 of the mass block 2 through a trachea 75, so that the cavity 21 of the mass block 2 is communicated with the outside atmosphere and the fluid can be pressed out; the micro electric push rod 73 is arranged in the gas cavity 712 of the cylinder block 71 and is electrically connected to a wire passing through the through hole 12 on the boring bar body 1 to realize the start and stop of the micro electric push rod 73; the telescopic end of the micro electric push rod 73 is fixedly connected to the piston 72 to adjust the position of the piston 72 in the cylinder block 71, and the control module 6 is electrically connected to the micro electric push rod 73 to realize the start and stop of the micro electric push rod 73.

[0037] In this embodiment, when the control module 6 calculates the optimal mass of the mass block 2, the piston 72 is driven by the micro electric push rod 73 to move along the axis direction of the cylinder block 71 to press the fluid in the liquid storage cavity 711 into the mass block 2 or extract the fluid in the mass block 2 into the liquid storage cavity 711 until the mass block 2 reaches the optimal mass; specifically, as Figure 1 shown, the left side of the piston 72 is the liquid storage cavity 711, and the right side is the gas cavity 712. When the micro electric push rod 73 drives the piston 72 to move to the left, the fluid in the liquid storage cavity 711 is pressed into the mass block 2. When the micro electric push rod 73 drives the piston 72 to move to the right, the liquid storage cavity 711 is in a negative pressure state, while the cavity 21 of the mass block 2 is under atmospheric pressure, and the fluid in the mass block 2 is pressed into the liquid storage cavity 711. It should be noted that when the cylinder block 71 is in a closed state (not communicated with the outside atmosphere), since the gas cavity 712 on the right side is communicated with the cavity 21 in the mass block 2, but the whole is still a closed cavity and the amount of gas is certain. Although the pressure in the gas cavity 712 on the right side and the cavity in the mass block 2 increases when pulling the piston 72 to move, the fluid can also be pressed out. However, as the piston 72 gradually moves to the right, the pressure will also gradually increase. On the one hand, it will cause the torque output by the electric cylinder to become larger, and on the other hand, the excessive pressure may cause air leakage problems in the cavities on both sides of the cylinder block 71 and cannot achieve the purpose of fluid regulation. Connecting the gas cavity 712 to the outside, the pressure in the gas cavity 712 remains unchanged no matter where the piston 72 moves. Therefore, the resistance of the piston 72 moving is reduced and there will be no liquid leakage problem, ensuring the reliability and stability of the mass adjustment of the mass block 2.

[0038] Furthermore, the fluid can be a high-density liquid and / or a high-viscosity liquid. When the fluid is a high-density liquid, since mass is related to density and volume, with a fixed volume, using a high-density liquid can shorten the time for fluid adjustment and accelerate the adjustment of the vibration frequency and amplitude of the mass block 2. The reason for using a high-viscosity liquid as the fluid is as follows: When the mass block 2 vibrates, the fluid inside the mass block 2 will inevitably vibrate, and the vibration direction of the fluid is opposite to that of the mass block 2. Therefore, although using fluid inside the mass block 2 can facilitate the change of the mass of the mass block 2, it will also reduce the vibration of the mass block 2, making the vibration of the boring bar body 1 unable to reach the optimal state. If a high-viscosity liquid is used, the adhesion between the high-viscosity liquid and the inner wall of the mass block 2 is relatively strong, and it can vibrate synchronously with the mass block 2, so the influence on the vibration of the mass block 2 is relatively small. In the later calculation of the optimal mass, the reverse vibration frequency brought by the high-viscosity liquid can be calculated and compensated for.

[0039] Furthermore, a number of magnetic ring units 9 are coaxially installed in the cavity of the mass block 2, and the magnetic ring units 9 fill the cavity of the mass block 2; the inner ring walls of the number of magnetic ring units 9 and the two end faces of the mass block 2 in the axial direction form a fluid accommodation cavity, and magnetorheological fluid is injected; each magnetic ring unit 9 includes a ring sleeve 91 and a number of electromagnetic coil mounts 92, and the number of electromagnetic coil mounts 92 are circumferentially and evenly installed on the inner wall of the ring sleeve 91. An electromagnetic coil 93 is wound on each electromagnetic coil mount 92, and the axial direction of the electromagnetic coil 93 is the same as the radial direction of the mass block 2. A wire is connected to each electromagnetic coil 93 and passes through the through hole 12 of the boring bar body 1 and is connected to a power source outside the boring bar body 1. Since magnetorheological fluid is a fluid with controllable fluidity, it exhibits the characteristics of a low-viscosity Newtonian fluid without an external magnetic field. When an external magnetic field is applied, it presents as a high-viscosity, low-fluidity Bingham fluid. There is a corresponding relationship between the viscosity of the liquid and the magnetic flux, and the conversion energy consumption is low, it is easy to control, and the response is rapid (millisecond level). When the control module 6 calculates and obtains the optimal mass required by the mass block 2 through the model, before the electromagnetic coil 93 is energized, magnetorheological fluid is injected into or pumped out of the mass block 2 through a pipeline. When the volume adjustment of the magnetorheological fluid is completed, the electromagnetic coil 93 is energized. Since the axial direction of the electromagnetic coil 93 is the same as the radial direction of the mass block 2, the electromagnetic coil 93 generates a magnetic field passing through the magnetorheological fluid when energized, and the magnetorheological fluid instantaneously becomes a solid-like state and can vibrate synchronously with the mass block 2, avoiding the influence of the reverse vibration of the fluid on the adjustment of the vibration frequency and amplitude of the mass block 2 and achieving precise adjustment.

[0040] Furthermore, as Figure 2 、 Figure 3 and Figure 4As shown, at least one end of the mass block 2 is connected to the installation cavity 11 of the boring bar body 1 through a damping adjustment unit 8 to produce a damping effect on the vibration of the mass block 2. The number of damping adjustment units 8 provided can be adjusted as needed, and their installation positions can also be arranged according to the actual situation.

[0041] Among them, as Figure 3 shown, the damping adjustment unit 8 includes a connecting sleeve 81, a capsule-shaped airbag 82, and an airbag fixing bracket 83 arranged axially in sequence. One end of the connecting sleeve 81 is connected to the end of the cantilever beam 3 away from the mass block 2 by screwing for easy installation. The other end of the connecting sleeve 81 is sleeved on one end of the capsule-shaped airbag 82 and is coaxial with the boring bar body 1 under the support of the capsule-shaped airbag 82. The other end of the capsule-shaped airbag 82 is fixed on the airbag fixing bracket 83. At the same time, the capsule-shaped airbag 82 is connected to a trachea passing through the through hole 12 in the boring bar body 1 to realize the inflation and deflation of the capsule-shaped airbag 82. The airbag fixing bracket 83 is fixedly installed in the installation cavity 11 of the boring bar body 1. One end of the airbag fixing bracket 83 facing the capsule-shaped airbag 82 is recessed inward and closely fits with the end of the capsule-shaped airbag 82 to achieve stable fixation and support. Since the mass block 2 is connected to the inner wall of the installation cavity 11 through the cantilever beam 3 and the damping adjustment unit 8, when the damping value of the damping adjustment unit 8 changes, the damping force received by the mass block 2 also changes, thereby changing the vibration frequency and amplitude of the mass block 2. During workpiece machining, the acceleration sensor 5 measures the vibration signal at the tool tip 4. The control module 6 analyzes the vibration frequency of the tool tip 4 through these signals, inputs this vibration frequency into the model established by the control module 6. The control module 6 calculates through the model to solve the required optimal damping. An air pump is provided on the trachea between the capsule-shaped airbag 82 and the air source. The control module 6 is electrically connected to the air pump, and the control module 6 controls the opening of the air pump to control the pressure in the capsule-shaped airbag 82, so that the damping reaches the optimal value.

[0042] Among them, as Figure 5As shown, the connecting sleeve 81 is trumpet-shaped. The flared end of the connecting sleeve 81 is sleeved on the end of the capsule-shaped airbag 82 and they are mutually extruded. The narrow end of the connecting sleeve 81 is connected to the cantilever beam 3. Since the connecting sleeve 81 adopts a trumpet-shaped structure, when the connecting sleeve 81 vibrates up and down with the mass block 2, there is sliding between the inner wall of the connecting sleeve 81 and the outer wall of the capsule-shaped airbag 82, and thus sliding friction will be generated. Therefore, the damping existing in the connection of the trumpet-shaped connecting sleeve 81 and the capsule-shaped airbag 82 is not only the air pressure of the capsule-shaped airbag 82, but also the damping effect achieved by consuming the vibration energy through friction. And with the inflation of the capsule-shaped airbag 82, the pressure between the capsule-shaped airbag 82 and the connecting sleeve 81 increases, then the frictional force also increases, the consumed vibration energy is more, and the damping effect is better. If the connecting sleeve 81 only adopts a cylindrical structure, after the connecting sleeve 81 is sleeved on the capsule-shaped airbag 82, then the air pressure value of the capsule-shaped airbag 82 is the damping force of the damping adjustment unit 8 on the mass block 2. The damping force is relatively single and the damping effect cannot be better achieved. In addition, the connecting sleeve 81 can be a rigid part or an elastic part. Since the airbag is capsule-shaped, when the capsule-shaped airbag 82 is inflated, both the radial dimension and the axial dimension of the capsule-shaped airbag 82 will increase. At this time, when the connecting sleeve 81 adopts an elastic part, the flared end of the connecting sleeve 81 is further expanded under the extrusion of the capsule-shaped airbag 82, the included angle between the barrel wall of the connecting sleeve 81 and the outer surface of the capsule-shaped airbag 82 becomes larger, the normal pressure of the sliding friction becomes larger, and the contact area between the two is larger, and the friction damping effect is better.

[0043] The working process of the present invention is further described below to further demonstrate the working principle and advantages of the present invention:

[0044] Before workpiece machining, parameters such as the rotational speed, cutting depth, and feed rate of the boring bar are input into the control module 6. During the machining of the workpiece, the tool head 4 transmits vibration to the boring bar body 1 and the mass block 2. The acceleration sensor 5 measures the vibration signal at the tool head 4 and transmits it to the control module 6. The control module 6 analyzes the vibration frequency of the tool head 4 through these signals, and then inputs the vibration frequency of the tool head 4 into the model established by the control module 6. At this time, the boring bar body 1 and the mass block 2 are at a constant natural frequency; the control module 6 calculates and solves the optimal mass and optimal damping required for the mass block 2 through the model, and then injects fluid into or extracts fluid from the cavity 21 of the mass block 2 through a pipeline to make the mass block 2 reach the optimal mass. At the same time, the pressure in the capsule-shaped airbag 82 is controlled by controlling the opening of the air pump, so that the damping reaches the optimal value; at this time, the vibration frequency of the mass block 2 changes, and under the action of the mass block 2, the vibration frequency and amplitude of the boring bar body 1 are the smallest, improving the machining accuracy of the workpiece surface.

[0045] While the present invention has been described herein with reference to particular embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the present invention. It should thus be understood that numerous modifications may be made to the exemplary embodiments, and other arrangements may be devised, without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that the different dependent claims and the features described herein may be combined in a manner different from that described in the original claims. It should also be understood that the features described in connection with separate embodiments may be used in other described embodiments.

Claims

1. A variable mass, variable damping vibration-reducing boring bar, comprising a boring bar body (1), a mass block (2), a cantilever beam (3), a cutter head (4), an acceleration sensor (5) and a control module (6), wherein the front end of the boring bar body (1) is provided with an open cavity along the central axis direction, the cutter head (4) is mounted on the front end of the boring bar body (1) through a cutter head connector, and the open cavity is sealed to form an installation cavity (11), the mass block (2) is connected to the cantilever beam (3) at both ends thereof, and the cantilever beam (3) is connected to the cantilever beam (3) at both ends thereof. The boring bar body (1) is axially mounted in a mounting cavity (11) and arranged close to a cutter head (4). The mass block (2) is suspended in the mounting cavity (11) to generate vibration in the opposite direction to the boring bar body (1). The acceleration sensor (5) is mounted at one end of the boring bar body (1) close to the cutter head (4) and is used to measure the vibration frequency of the boring bar body (1). The control module (6) is arranged outside the boring bar body (1) and is electrically connected to the acceleration sensor (5). The invention is characterized in that: The mass block (2) has a cavity (21) therein, and a fluid is injected into the cavity (21). The mass of the mass block (2) is changed by adjusting the volume of the fluid, thereby adjusting the vibration frequency of the boring bar body (1); The vibration-damping boring bar further comprises a fluid regulating unit (7), which is arranged in the mounting cavity (11) of the boring bar body (1) and is arranged away from the cutter head (4), and the fluid regulating unit (7) is connected to the cavity (21) in the mass block (2) to adjust the volume of the fluid in the cavity (21); The fluid regulating unit (7) is a piston-type electric cylinder structure, comprising a cylinder body (71), a piston (72) and a micro electric push rod (73); the cylinder body (71) is fixedly installed in the installation cavity (11); the piston (72) is slidably installed in the inner cavity of the cylinder body (71) and divides the inner cavity of the cylinder body (71) into a liquid storage cavity (711) and an air cavity (712); the liquid storage cavity (711) is connected to the cavity (21) of the mass block (2) through a liquid inlet and outlet pipe (74) to regulate the mass block ( 2) the volume of the fluid inside; the air cavity (712) is connected to the cavity (21) of the mass (2) through the air pipe (75) to press the fluid out; the micro electric push rod (73) is arranged in the air cavity (712) of the cylinder body (71), the telescopic end of the micro electric push rod (73) is fixedly connected to the piston (72) to adjust the position of the piston (72) in the cylinder body (71), and the control module (6) is electrically connected to the micro electric push rod (73) to realize the start and stop of the micro electric push rod (73); At least one end of the mass block (2) is connected to the mounting cavity (11) of the boring bar body (1) through a damping adjustment unit (8) to produce a damping effect on the vibration of the mass block (2); The damping adjustment unit (8) comprises a connecting sleeve (81), a capsule-shaped airbag (82) and an airbag fixing frame (83) which are arranged in sequence in the axial direction; one end of the connecting sleeve (81) is detachably connected to one end of the cantilever beam (3); the other end of the connecting sleeve (81) is sleeved on one end of the capsule-shaped airbag (82); the other end of the capsule-shaped airbag (82) is fixed in the mounting cavity (11) in the boring bar body (1) through the airbag fixing frame (83); and the damping force is changed by adjusting the air pressure of the capsule-shaped airbag (82); The connecting sleeve (81) is trumpet-shaped, the expanded end of the connecting sleeve (81) is sleeved on the end of the capsule-shaped airbag (82) to produce mutual extrusion, and the narrow end of the connecting sleeve (81) is connected to the cantilever beam (3).

2. A variable mass, variable damping vibration-reducing boring bar according to claim 1, characterized in that: The air cavity (712) is communicated with the outside atmosphere.

3. A variable mass, variable damping vibration-reducing boring bar according to claim 1, characterized in that: The fluid injected into the mass block (2) is a high-density liquid and / or a high-viscosity liquid.

4. A variable mass, variable damping vibration-reducing boring bar according to claim 1, characterized in that: A plurality of magnetic ring units (9) are coaxially mounted in the cavity of the mass block (2); the inner ring walls of the plurality of magnetic ring units (9) and the end faces of both ends of the mass block (2) form a fluid containing cavity, and magnetorheological fluid is injected into the cavity; each magnetic ring unit (9) comprises an annular sleeve (91) and a plurality of electromagnetic coil mounting seats (92); the plurality of electromagnetic coil mounting seats (92) are evenly mounted on the inner wall of the annular sleeve (91) in the circumferential direction; an electromagnetic coil (93) is wound around each electromagnetic coil mounting seat (92), and the axial direction of the electromagnetic coil (93) is the same as the radial direction of the mass block (2).

5. A variable mass and variable damping vibration-reducing boring bar according to claim 4, characterized in that: The connecting sleeve (81) is a rigid part.

6. A variable mass and variable damping vibration-reducing boring bar according to claim 4, characterized in that: The connecting sleeve (81) is an elastic member.

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