A spiral variable mass vibration damping boring bar

Abstract

The present invention discloses a spiral variable mass vibration damping boring bar, which relates to the field of mechanical manufacturing and processing, and comprises a rod body and a cantilever beam arranged inside the rod body, a cavity is arranged between the cantilever beam and the inner wall of the rod body, a motor sleeve is arranged in the cavity, the motor sleeve and the rotating sleeve are connected according to a linear track, the spiral cover plate on the rotating sleeve is spirally connected with the mass block, a spiral groove is arranged on the mass block, the spiral groove is arranged between the left and right end faces of the mass block, the spiral groove is arranged as a fixed depth deep groove from the left to the middle, and the spiral groove is arranged as a fixed depth shallow groove from the middle to the right, the bottom diameter of the deep groove is greater than the diameter of the cantilever beam, the depth of the shallow groove is less than the diameter of the cantilever beam, a baffle is arranged at one end of the deep groove, the baffle is in a spiral array, and the baffle spacing is adjustable. The present invention adopts the above-mentioned spiral variable mass vibration damping boring bar, and adjusts the vibration damping performance of the vibration damping boring bar by adjusting the mass of the vibration absorber vibration absorber block, thereby achieving the purpose of optimal vibration reduction.

Description

Technical Field

[0001] The invention relates to the technical field of mechanical manufacturing, in particular to a spiral variable mass vibration damping boring bar. Background Art

[0002] Boring is a critical part machining method in the machinery manufacturing industry, widely used in aerospace, precision machinery, instrumentation, and automotive manufacturing. Part precision directly impacts its performance and lifespan. However, during the boring process, impact forces can generate vibrations, leading to a decrease in surface quality. Under certain conditions, chatter can also occur, severely impacting cutting stability. The relative vibration between the toolholder and the workpiece can leave vibration marks on the machined surface, reducing part precision, shortening toolholder life, and even rendering the cutting process impossible.

[0003] Boring bars are widely used in deep hole machining. However, due to the low stiffness of their cantilever beam structure, vibration problems often occur when the length-to-diameter ratio of the boring bar is large, which not only affects the machining accuracy but may also damage the tool.

[0004] Therefore, a spiral variable mass vibration damping boring bar is provided to solve the above problems. Summary of the Invention

[0005] The present invention aims to provide a spiral variable mass vibration-damping boring bar. Based on the theory of dynamic vibration absorption, a variable mass vibration absorber is designed. By adjusting the mass of the vibration absorber, the vibration damping performance of the vibration-damping boring bar can be adjusted, thereby achieving the purpose of optimal vibration reduction.

[0006] To achieve the above-mentioned purpose, the present invention provides a spiral variable mass vibration damping boring bar, comprising a rod body and a cantilever beam arranged inside the rod body, a cavity being provided between the cantilever beam and the inner wall of the rod body, a motor sleeve being provided in the cavity, the motor sleeve and the rotating sleeve being matched according to a linear track, the spiral cover plate on the rotating sleeve being spirally matched with the mass block, a spiral groove being provided on the mass block, the spiral groove being arranged between the left and right end faces of the mass block, the spiral groove being arranged as a deep groove with a fixed depth from the left side to the middle, and the spiral groove being arranged as a shallow groove with a fixed depth from the middle to the right side, the bottom diameter of the deep groove being greater than the diameter of the cantilever beam, the depth of the shallow groove being less than the diameter of the cantilever beam, a baffle being provided at one end of the deep groove, the baffle being in a spiral array, a motor sleeve gasket being provided at one end of the motor sleeve, a motor sleeve pressure plate being provided at one end of the motor sleeve, a motor gasket being fixedly connected to the base of the servo motor, the outer rotor of the servo motor being fixedly connected to the motor sleeve, and the motor gasket being connected to the control unit and the power supply through a wire.

[0007] Preferably, a cutter head is provided at one end of the rod body, and the cutter head is fixedly connected to the cantilever beam through a cutter head connector. An acceleration sensor is provided at the cutter head, and the accelerometer sensor is connected to the control unit through a wire to extract the fluctuation amplitude FA and the excitation frequency ω of the cutting force, and a control algorithm is integrated in the control unit.

[0008] Preferably, the motor sleeve gasket is concentrically connected to an end face of the motor sleeve away from the servo motor, and the axial movement of the motor sleeve is fixed by the motor sleeve pressure plate. The inner circle part of the motor sleeve pressure plate coincides with the mass block and is fixed with bolts, and a gap is provided between the outer circle part of the motor sleeve pressure plate and the motor sleeve gasket.

[0009] Preferably, the baffle spacing is adjustable, the rotating sleeve moves left and right by rotating on the mass block, the spiral cover plate cooperates with the baffle of the spiral groove to form a closed space, the right end face of the rotating sleeve is flush with the end face of the spiral groove away from the baffle, and the other end face of the motor gasket is fixedly connected to the end face of the spiral groove away from the baffle.

[0010] Preferably, the servo motor is configured as a hollow torque servo motor, and the rotation of the hollow torque servo motor drives the motor sleeve to rotate in a fixed direction.

[0011] Preferably, the motor sleeve, the rotating sleeve, the motor sleeve pressure plate and the motor sleeve gasket are all arranged on the cantilever beam, and high-density damping oil is filled in the cavity.

[0012] Preferably, the control method of the control algorithm in the control unit specifically includes:

[0013] S1: When measuring the cutting force on the boring bar during the first test cut, the acceleration sensor extracts the fluctuation amplitude FA and the excitation frequency ω of the cutting force;

[0014] S2: When cutting the second cut, the dynamic parameters of the boring bar, the fluctuation amplitude FA of the cutting force, and the excitation frequency ω are brought into the dynamic equation to draw the amplitude magnification curve;

[0015] The amplitude magnification of the boring bar is expressed as:

[0016]

[0017] Where A1 is the steady-state vibration amplitude of the main system, A st is the static deformation, ω is the angular frequency of the simple harmonic excitation force; ζ is the subsystem damping ratio, ω1 is the natural frequency ratio of the main system, ω2 is the natural frequency ratio of the subsystem;

[0018] in Expressed as:

[0019]

[0020] Where, FA is the amplitude of the simple harmonic force; the damping ratio of the main system Main system natural frequency ratio Subsystem damping ratio Subsystem natural frequency ratio static deformation Mass ratio K1 is the main system stiffness, k2 is the subsystem stiffness. C1 is the main system damping, c2 is the subsystem damping, M1 is the rod equivalent mass, and m2 is the absorber mass.

[0021] In the formula In, F A is the amplitude of the simple harmonic force:

[0022] a=(K1+k2-M1ω 2 )(k2-m2ω 2 )-k2 2 -(C1+c2)c2ω 2 +c2 2 ω 2

[0023] b=(K1+k2-M1ω 2 )c2ω+(k2-m2ω 2 )(C1+c2)ω+2(K1+k2)c2ω;

[0024] d=c2ω;

[0025] h=k2-m2ω 2 ;

[0026] S3: Find the mass of the vibration absorbing block corresponding to the minimum point of the amplitude magnification curve;

[0027] S4: The mass of the vibration absorber's absorbing block is adjusted by rotating the hollow torque servo motor a certain number of revolutions or angles, achieving optimal vibration damping performance for the damped boring bar. The hollow torque servo motor can control the angle of rotation. Once energized, the hollow torque servo motor cannot be rotated manually, and it also serves to lock the rotating sleeve and motor sleeve. The control unit controls the angle of rotation of the hollow torque servo motor.

[0028] Preferably, the motor sleeve has four square holes distributed axially, so that the high-density damping fluid in the cavity fills the deep spiral groove.

[0029] Preferably, the rotating sleeve is made of a lightweight material, such as carbon fiber or titanium. This lightweight material is used to minimize the effect of the rotating sleeve's left and right movement on the cantilever beam's stiffness. When the rotating sleeve is at its rightmost position, the cantilever beam's stiffness is minimal, and vice versa. The lightweight material is used to minimize this effect.

[0030] Therefore, the present invention adopts the above-mentioned spiral variable mass vibration-damping boring bar, and adjusts the vibration-damping performance of the vibration-damping boring bar by adjusting the mass of the vibration-absorbing block of the vibration absorber, thereby achieving the purpose of optimal vibration reduction.

[0031] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a cross-sectional view of the overall structure of a spiral variable mass vibration damping boring bar of the present invention;

[0033] Figure 2 This is an overall view of the mass block in a spiral variable mass vibration damping boring bar of the present invention;

[0034] Figure 3 This is a schematic diagram of a motor sleeve in a spiral variable mass vibration damping boring bar of the present invention;

[0035] Figure 4 This is an enlarged view of a rotating sleeve in a spiral variable mass vibration damping boring bar of the present invention;

[0036] Figure 5 is a schematic diagram of the spiral cover plate of the present invention;

[0037] Figure 6 This is an enlarged view of a motor sleeve gasket in a spiral variable mass vibration damping boring bar of the present invention;

[0038] Figure 7 This is an overall enlarged view of a vibration absorber in a spiral variable mass vibration damping boring bar of the present invention;

[0039] Figure 8 This is a schematic diagram of the front position of the rotating sleeve in an embodiment of the present invention;

[0040] Figure 9 2 is a schematic diagram of the middle position of the rotating sleeve in an embodiment of the present invention;

[0041] Figure 10 2. It is a schematic diagram of the rear position of the rotating sleeve in an embodiment of the present invention;

[0042] Figure 11 This is a schematic diagram of the external structure of a spiral variable mass vibration damping boring bar of the present invention;

[0043] Reference numerals

[0044] 1. Cutting head; 2. Cutting head connector; 3. Rod body; 4. Cantilever beam; 5. Motor sleeve pressure plate; 6. Motor sleeve gasket; 7. Motor sleeve; 8. Mass block; 801. Baffle; 9. Rotating sleeve; 901. Spiral cover; 10. Motor gasket; 11. Hollow torque servo motor; 12. Wire; 13. Control unit; 14. Power supply; 15. Acceleration sensor; 16. Rubber plug. DETAILED DESCRIPTION

[0045] The technical solution of the present invention is further described below with reference to the accompanying drawings and embodiments.

[0046] Unless otherwise defined, the technical or scientific terms used in the present invention shall have the usual meanings understood by persons of ordinary skill in the field to which the present invention belongs. The words "first", "second" and similar terms used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Words such as "include" or "comprise" mean that the elements or objects preceding the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connect" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0047] As attached Figures 1-11As shown, the present invention provides a spiral variable mass vibration damping boring bar, including a rod body 3 and a cantilever beam 4 arranged inside the rod body 3, a cavity is provided between the cantilever beam 4 and the inner wall of the rod body 3, a motor sleeve 7 is provided in the cavity, the motor sleeve 7 and the rotating sleeve 9 are connected according to a linear track, the linear tracks are provided in 4 pieces, the spiral cover plate 901 is spirally connected to the mass block 8, a motor sleeve gasket 6 is provided at one end of the motor sleeve 7, a motor sleeve pressure plate 5 is provided at one end of the motor sleeve 7, a motor gasket 10 is provided at the other end of the motor sleeve 7, the motor gasket 10 is fixedly connected to the base of the servo motor, the outer rotor of the servo motor is fixedly connected to the motor sleeve 7, and the motor gasket 10 is connected to the control unit 13 and the power supply 14 through a wire 12. A spiral cover plate 901 is provided on the inner wall of the rotating sleeve 9, and the spiral cover plate 901 cooperates with the baffle 801 and the shallow groove provided on the mass block 8, and the height of the baffle 801 is flush with the bottom of the shallow groove; a spiral groove is provided on the mass block 8, and the spiral groove is provided between the left and right end faces of the mass block 8. The spiral groove is set as a deep groove with a fixed depth from the left to the middle, and the spiral groove is set as a shallow groove with a fixed depth from the middle to the right. The bottom diameter of the deep groove is larger than the diameter of the cantilever beam 4, and the depth of the shallow groove is smaller than the diameter of the cantilever beam 4. A baffle 801 is provided at one end of the deep groove, and the interval of the baffle 801 is adjustable. The rotating sleeve 9 moves left and right by rotating on the mass block 8, and the spiral cover plate 901 cooperates with the baffle of the spiral groove to form a closed space, which encloses the damping oil, increases the mass of the mass block 8 and the damping oil will not shake in the closed space. The right end face of the rotating sleeve 9 is flush with the end face of the spiral groove away from the baffle, and the other end face of the motor gasket 10 is fixedly connected to the end face of the spiral groove away from the baffle. The servo motor is configured as a hollow torque servo motor 11. The rotation of the hollow torque servo motor 11 drives the motor sleeve 7 to rotate in a fixed direction. The rotating sleeve 9 rotates from left to right on the mass block 8, forming three configurations: front, middle, and back. Because the spiral grooves at both ends of the mass block 8 do not open the left and right end faces of the mass block 8, the rotating sleeve 9 cannot continue forward when it rotates to the left / right end, and is reversed by the servo motor.

[0048] A cutter head 1 is provided at one end of the rod body 3, and the cutter head 1 is fixedly connected to the cantilever beam 4 through a cutter head connector 2. An acceleration sensor 15 is provided at the cutter head 1, and the accelerometer sensor 15 is connected to the control unit 13 through a wire 12. A rubber plug 16 is provided at the tail end of the wire 12 channel, and there is a hole in the middle of the rubber plug 16 to facilitate the passage of the wire 12. The accelerometer sensor extracts the fluctuation amplitude FA and the excitation frequency ω of the cutting force, and the control algorithm is integrated in the control unit 13.

[0049] The control method of the control algorithm in the control unit 13 specifically includes:

[0050] S1: When measuring the cutting force on the boring bar during the first test cut, the acceleration sensor extracts the fluctuation amplitude FA and the excitation frequency ω of the cutting force;

[0051] S2: When cutting the second cut, the dynamic parameters of the boring bar, the fluctuation amplitude FA of the cutting force, and the excitation frequency ω are brought into the dynamic equation to draw the amplitude magnification curve;

[0052] The amplitude magnification of the boring bar is expressed as:

[0053]

[0054] Where A1 is the steady-state vibration amplitude of the main system, A st is the static deformation, ω is the angular frequency of the simple harmonic excitation force; ζ is the subsystem damping ratio, ω1 is the natural frequency ratio of the main system, ω2 is the natural frequency ratio of the subsystem;

[0055] in Expressed as:

[0056]

[0057] Where, F A is the amplitude of the simple harmonic force; the damping ratio of the main system Main system natural frequency ratio Subsystem damping ratio Subsystem natural frequency ratio static deformation Mass ratio K1 is the main system stiffness, k2 is the subsystem stiffness. C1 is the main system damping, c2 is the subsystem damping, M1 is the rod equivalent mass, and m2 is the absorber mass.

[0058] In the formula In, F A is the amplitude of the simple harmonic force:

[0059] a=(K1+k2-M1ω 2 )(k2-m2ω 2 )-k2 2 -(C1+c2)c2ω 2 +c2 2 ω 2

[0060] b=(K1+k2-M1ω 2 )c2ω+(k2-m2ω 2 )(C1+c2)ω+2(K1+k2)c2ω;

[0061] d=c2ω;

[0062] h=k2-m2ω 2;

[0063] S3: Find the mass of the vibration absorbing block corresponding to the minimum point of the amplitude magnification curve;

[0064] S4: The mass of the vibration absorber's vibration absorbing block is adjusted by rotating the hollow torque servo motor a certain number of turns or angles to complete the adjustment of the optimal vibration reduction performance of the vibration reduction boring bar.

[0065] The hollow torque servo motor 11 can control the rotation angle. When powered, it cannot be rotated manually, which also serves to lock the rotating sleeve 9 and the motor sleeve 7. The rotation angle of the hollow torque servo motor 11 is controlled by the control unit 13. The motor sleeve 7 has four square holes distributed axially to facilitate the passage of damping oil. These four holes allow the high-density damping fluid in the cavity to fill the deep spiral groove.

[0066] The motor sleeve gasket 6 is concentrically connected to the end face of the motor sleeve 7 away from the servo motor. The axial movement of the motor sleeve 7 is fixed by the motor sleeve pressure plate 5. The inner circle part of the motor sleeve pressure plate 5 overlaps with the mass block 8 and is fixed with bolts. A gap is set between the outer circle part of the motor sleeve pressure plate 5 and the motor sleeve gasket 6, which will not hinder the rotation of the motor sleeve 7.

[0067] The rotating sleeve 9 is made of a lightweight material, such as carbon fiber or titanium. This lightweight material is used to minimize the effect of the rotating sleeve 9's left and right movement on the stiffness of the cantilever beam 4. When the rotating sleeve 9 is at its rightmost position, the stiffness of the cantilever beam 4 is minimal, and vice versa. The lightweight material is used to minimize this effect.

[0068] The motor sleeve 7, rotating sleeve 9, motor sleeve pressure plate 5 and motor sleeve gasket 6 are all arranged on the cantilever beam 4, and high-density damping oil is filled in the cavity. First, the damping oil is added to provide a damping force when the vibration absorber vibrates up and down. Secondly, the high-density damping oil can quickly adjust the mass of the vibration absorber through the rotating sleeve. The mass of the vibration absorber's vibration absorbing block has a great influence on the vibration absorption performance. By moving the rotating sleeve 9 to the left, the high-density damping oil is locked in the closed spaces formed by the rotating sleeve 9 and the baffles deeper in the spiral of the mass block 8. The damping oil will not shake due to operation. The further it moves to the left, the greater the locked mass is, thereby achieving the adjustment of the mass of the vibration absorbing block, thereby achieving the adjustment of the vibration reduction performance of the vibration-damping boring bar.

[0069] Therefore, the present invention adopts the above-mentioned spiral variable mass vibration-damping boring bar, and adjusts the vibration-damping performance of the vibration-damping boring bar by adjusting the mass of the vibration absorber, thereby achieving the purpose of optimal vibration reduction.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solutions of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A spiral variable mass vibration damping boring bar, characterized by: The cam is provided with a motor, and the motor is mounted on a drive link, wherein the motor is mounted on a drive link, wherein the motor is mounted on a drive link, wherein the motor is mounted on a drive link, wherein the motor is mounted on a drive link, wherein the motor is mounted on a drive link, wherein the motor is mounted on a drive link, wherein the motor is mounted on a drive link, wherein the motor is mounted on the drive link, 2. The spiral variable mass vibration damping boring bar according to claim 1, characterized in that: A cutter head is provided at one end of the rod body, and the cutter head is fixedly connected to the cantilever beam through a cutter head connector. An acceleration sensor is provided at the cutter head, and the accelerometer sensor is connected to the control unit through a wire to extract the fluctuation amplitude of the cutting force. F A The control algorithm is integrated in the control unit with the excitation frequency ω.

3. The spiral variable mass vibration damping boring bar according to claim 1, characterized in that: The motor sleeve gasket is concentrically connected to the end face of the motor sleeve away from the servo motor. The axial movement of the motor sleeve is fixed by the motor sleeve pressure plate. The inner circle part of the motor sleeve pressure plate coincides with the mass block and is fixed with bolts. A gap is set between the outer circle part of the motor sleeve pressure plate and the motor sleeve gasket.

4. The spiral variable mass vibration damping boring bar according to claim 1, characterized in that: The baffle spacing is adjustable, and the rotating sleeve moves left and right by rotating on the mass block. The spiral cover plate cooperates with the baffle of the spiral groove to form a closed space. The right end face of the rotating sleeve is flush with the end face of the spiral groove away from the baffle, and the other end face of the motor gasket is fixedly connected to the end face of the spiral groove away from the baffle.

5. The spiral variable mass vibration damping boring bar according to claim 1, characterized in that: The servo motor is configured as a hollow torque servo motor, and the rotation of the hollow torque servo motor drives the motor sleeve to rotate in a fixed direction.

6. The spiral variable mass vibration damping boring bar according to claim 1, characterized in that: The motor sleeve, the rotating sleeve, the motor sleeve pressure plate and the motor sleeve gasket are all arranged on the cantilever beam, and high-density damping oil is filled in the cavity.

7. The spiral variable mass vibration damping boring bar according to claim 2, characterized in that: The control method of the control algorithm within the control unit specifically includes: S1: When testing the first cut to measure the cutting force on the boring bar, the acceleration sensor extracts the fluctuation amplitude of the cutting force F A and the excitation frequency ω; S2: The dynamic parameters of the boring bar and the fluctuation amplitude of the cutting force when cutting the second cut F A Substitute the excitation frequency ω into the dynamic equation to draw the amplitude-rate curve; The amplitude magnification of the boring bar is expressed as: In the formula A 1 is the steady-state vibration amplitude of the main system, , is static deformation, ω is the excitation frequency; is the subsystem damping ratio, The natural frequency ratio of the main system, Subsystem natural frequency ratio; in Expressed as: ； Where, F A is the fluctuation amplitude of cutting force; the damping ratio of main system ; Main system natural frequency ratio ; Subsystem damping ratio ; Subsystem natural frequency ratio Static deformation ; is the static force; mass ratio ; is the main system stiffness, is the subsystem stiffness; For main system damping, is the subsystem damping, is the equivalent mass of the rod, is the mass of the vibration absorber; In the formula middle, F A is the fluctuation amplitude of cutting force: ； ； ； ； S3: Find the mass of the vibration absorbing block corresponding to the minimum point of the amplitude magnification curve; S4: The mass of the vibration absorber's vibration absorbing block is adjusted by rotating the hollow torque servo motor a certain number of turns or angles to complete the adjustment of the optimal vibration reduction performance of the vibration reduction boring bar.

8. The spiral variable mass vibration damping boring bar according to claim 1, characterized in that: There are four square holes distributed axially on the motor sleeve.

9. The spiral variable mass vibration damping boring bar according to claim 1, characterized in that: The rotating sleeve is made of a lightweight piece and is configured to be carbon fiber or titanium.

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