A damping boring bar with an online adjustable absorber position and its working method

Abstract

The present invention discloses a vibration damping boring bar with an online adjustable absorber position and a working method, belonging to the technical field of machining. It includes a vibration absorption cavity and a gear pump arranged in the boring bar. An absorber with a piston structure that can reciprocate in the vibration absorption cavity is installed in the vibration absorption cavity. The vibration absorption cavity includes a front cavity and a rear cavity. Both the front cavity and the rear cavity are connected to the gear pump through pipelines. The front cavity and the rear cavity are filled with damping fluid controlled by the gear pump. By changing the pressure oil in the front cavity and the rear cavity through the gear pump, a plurality of acceleration sensors are arranged along the vibration absorption cavity. The vibration frequency of the boring bar is detected by the acceleration sensors to change the damping fluid in the front cavity and the rear cavity, thereby changing the position of the absorber and realizing real-time vibration damping of the boring bar. For different vibration modes of the boring bar, the position of the absorber is adjusted online so that it is always located at the position with the largest amplitude of the boring bar, enabling the absorber to achieve a better vibration absorption effect, reducing the vibration during part machining, and improving the quality of the machined surface.

Description

Technical Field

[0001] The present invention belongs to the technical field of machining, and is particularly applicable to a vibration-damping boring bar with an online adjustable absorber position and a working method thereof. Background Art

[0002] In machining, a boring bar is usually used for hole machining. During boring, the cutting blade periodically cuts into and out of the workpiece. Different cutting parameters and changes in cutting materials will cause fluctuations in the cutting force, which in turn leads to vibration of the boring bar and even induces chatter instability. It should be noted that under different cutting forces, the vibration modes of the boring bar are different, and the amplitudes of the boring bar at different axial positions are also different. In the prior art, vibration damping of the boring bar is usually achieved by installing vibration damping blocks on the outside or inside of the boring bar, and the vibration of the boring bar is reduced by absorbing vibration. However, if the absorber is located at the node position of the vibration mode, since the amplitude at the node position is zero, the absorber cannot be sufficiently excited and it is difficult to exert its vibration absorption performance. Obviously, when the absorber is located at the position with the maximum amplitude of the boring bar, it is most likely to excite the vibration of the absorber. However, the existing absorbers generally have a fixed position and cannot be adjusted online, which limits the performance of the absorber. Summary of the Invention

[0003] Technical Problem: Aiming at the deficiencies of the prior art, a vibration-damping boring bar with an online adjustable absorber position and a working method thereof are provided. The structure is simple and easy to use, and it can be adjusted in real time according to the cutting object or process, so as to effectively control the vibration of the boring bar from beginning to end. The structure is simple and the use effect is good.

[0004] Technical Solution: To achieve the above technical purpose, a vibration-damping boring bar with an online adjustable absorber position of the present invention includes a cylindrical absorber cavity provided in the boring bar. A gear pump is provided behind the absorber cavity. An absorber with a piston structure that can reciprocate in the absorber cavity is installed in the absorber cavity. The absorber cavity is divided into two independent front cavities and rear cavities by the absorber. The end of the front cavity and the tail of the rear cavity are both connected to the inlet and outlet of the gear pump through pipelines. The front cavity and the rear cavity are filled with damping fluid controlled by the gear pump. By changing the pressure oil in the front cavity and the rear cavity through the gear pump, a plurality of acceleration sensors are arranged along the absorber cavity. The acceleration sensors are connected to a controller, and the controller is connected to the gear pump. During use, the vibration frequency of the boring bar is detected by the acceleration sensors, and the controller controls the gear pump to change the damping fluid in the front cavity and the rear cavity, thereby changing the position of the absorber, so as to achieve real-time vibration damping of the boring bar.

[0005] A vibration damping boring bar with an online adjustable absorber position includes a vibration absorption cavity arranged inside the boring bar. An absorber is provided in the vibration absorption cavity. The vibration absorption cavity is divided into a front cavity and a rear cavity by the absorber. An end rubber bladder is provided in the front cavity, and a tail rubber bladder is provided in the rear cavity. The absorber is arranged between the end rubber bladder and the tail rubber bladder. The end rubber bladder has an opening at the front end, and the tail rubber bladder has an opening at the tail end. The openings are both connected to a gear pump through pipelines to form an internal closed-loop passage.

[0006] A plurality of acceleration sensors are arranged along the axial direction of the boring bar. The abscissa positions of the acceleration sensors are successively x i (i = 1, 2, ……, n). All the acceleration sensors are connected to a controller. The controller collects and calculates the mean square value of the vibration acceleration of each acceleration sensor, which is successively marked as y i (i = 1, 2, ……, n). The controller performs polynomial fitting on the mean square values (x i , y i ) at each location along the axial direction to obtain the vibration mode curve y = y(x) of the boring bar, and then obtains the maximum position of the amplitude of the boring bar. The maximum position is marked as x max ;

[0007] The controller drives the gear pump to work, driving the damping liquid to flow between the end rubber bladder and the tail rubber bladder. When the damping liquid flows from the end rubber bladder to the tail rubber bladder, the tail rubber bladder expands and the end rubber bladder shrinks. The absorber moves towards the end of the vibration absorption cavity under the thrust of the tail rubber bladder. Conversely, the absorber moves towards the tail of the vibration absorption cavity.

[0008] Furthermore, the absorber includes a mass block, and the outside of the mass block is wrapped with a rubber bushing. The rubber bushing can slide without resistance with the vibration absorption cavity.

[0009] Furthermore, the outer walls of the end rubber bladder and the tail rubber bladder are both made of elastic rubber material. The end rubber bladder and the tail rubber bladder have the same volume. A single end rubber bladder and tail rubber bladder can move the absorber to one end of the vibration absorption cavity by introducing damping liquid. The volume of the end rubber bladder and the tail rubber bladder increases or decreases according to the amount of damping liquid filled, generating a pressure to support the absorber.

[0010] Furthermore, the acceleration sensors are arranged axially close to the vibration absorption cavity.

[0011] A working method of a vibration damping boring bar with an online adjustable absorber position is as follows:

[0012] When the boring bar starts to work, under the action of an external excitation, the absorber vibrates, and then drives the end rubber bladder and the tail rubber bladder to vibrate together. The damping liquid dissipates the vibration energy through the damping effect.

[0013] The controller starts multiple acceleration sensors arranged along the axial direction of the boring bar. The horizontal coordinate positions of the acceleration sensors are x i (i=1,2,……,n), the vibration state of the boring bar is collected in real time by the acceleration sensor, and the vibration state of the boring bar is sent to the controller. The controller collects and calculates the mean square value of the vibration acceleration of each acceleration sensor, which is marked as y i (i=1,2,……,n), the controller adjusts the mean square value (x i ,y i ) is fitted with a polynomial to obtain the vibration mode curve y=y(x) of the boring bar, and then the maximum position x of the boring bar amplitude is calibrated. max ;

[0014] The controller controls the gear pump to adjust the volume ratio of the damping liquid in the end rubber sac and the tail rubber sac, thereby moving the vibration absorber to the maximum vibration position x of the boring bar corresponding to the vibration absorption cavity. max The position of the vibration absorber is thus optimized to achieve the best vibration absorbing effect;

[0015] When the boring bar changes the cutting plan or cutting object, the controller quickly regains the maximum position x of the current boring bar amplitude through the acceleration sensor. max , and then the controller re-controls the gear pump to change the position of the vibration absorber to the maximum position x of the current boring bar amplitude max The corresponding position in the vibration absorption cavity.

[0016] Furthermore, when the damping fluid flows from the end rubber sac to the tail rubber sac, the tail rubber sac expands and the end rubber sac shrinks, and the vibration absorber moves toward the end of the boring bar under the thrust of the tail rubber sac, and vice versa, the vibration absorber moves toward the tail of the boring bar;

[0017] Furthermore, assuming that the initial position of the vibration absorber is x0 and the diameter of the damping fluid is d, the distance to be moved is Δx = |x0-x max |, the amount of damping liquid between the end rubber sac and the tail rubber sac Through real-time adjustment by the controller, the vibration absorber position is always located at the maximum amplitude position x of the boring bar. max The corresponding vibration absorption cavity enables the vibration absorber to play a better vibration absorption effect, reduce the vibration during part processing, and improve the quality of the processed surface.

[0018] Beneficial effects:

[0019] This device has a simple structure and is easy to use. By adjusting the position of the vibration absorber in the vibration absorption cavity, the vibration of the boring bar can be controlled. Its adjustment speed is fast, and it can be adjusted in real time according to the cutting object or process, so as to effectively control the vibration of the boring bar from beginning to end. For different vibration modes of the boring bar, the position of the vibration absorber is adjusted online in real time so that it is always located at the position with the largest amplitude of the boring bar, enabling the vibration absorber to achieve a better vibration absorption effect, reducing the vibration during part processing, and improving the quality of the machined surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Explain the meanings represented by each drawing

[0021] Figure 1 It is a schematic structural diagram of a vibration-damping boring bar with an online adjustable position of the vibration absorber of the present invention;

[0022] Figure 2 It is a schematic structural diagram of the vibration absorber of the present invention;

[0023] In the figure: 1, boring bar; 2, acceleration sensor; 3, end rubber bladder; 4, vibration absorber; 5, tail rubber bladder; 6, damping liquid; 7, controller; 8, gear pump, 41, rubber bushing; 42, mass block. DETAILED DESCRIPTION OF THE INVENTION

[0024] The present invention will be further described below with reference to the accompanying drawings.

[0025] As Figure 1 shown, a vibration-damping boring bar with an online adjustable position of the vibration absorber of the present invention includes a vibration absorption cavity provided in the boring bar 1. A gear pump 8 is provided behind the vibration absorption cavity. A vibration absorber 4 with a piston structure that can reciprocate in the vibration absorption cavity is installed in the vibration absorption cavity. The vibration absorption cavity is divided into two independent front cavities and rear cavities by the vibration absorber 4. The end of the front cavity and the tail of the rear cavity are both connected to the liquid inlet and outlet of the gear pump 8 through pipelines. The front cavity and the rear cavity are filled with damping liquid 6 controlled by the gear pump 8. By changing the pressure oil in the front cavity and the rear cavity through the gear pump 8, a plurality of acceleration sensors 2 are provided along the vibration absorption cavity. The acceleration sensors 2 are connected to a controller 7, and the controller 7 is connected to the gear pump 8. During use, the vibration frequency of the boring bar 1 is detected by the acceleration sensors 2, and the controller 7 controls the gear pump 8 to change the damping liquid 6 in the front cavity and the rear cavity, thereby changing the position of the vibration absorber 4, so as to achieve real-time vibration damping of the boring bar 1.

[0026] A vibration-damping boring bar with an online adjustable absorber position, comprising a vibration absorption cavity arranged inside the boring bar 1. An absorber 4 is arranged in the vibration absorption cavity. The vibration absorption cavity is divided into a front cavity and a rear cavity by the absorber 4. An end rubber bladder 3 is arranged in the front cavity, and a tail rubber bladder 5 is arranged in the rear cavity. The absorber 4 is arranged between the end rubber bladder 3 and the tail rubber bladder 5. The end rubber bladder 3 has an opening at the front end, and the tail rubber bladder 5 has an opening at the tail end. The openings are both connected to a gear pump 8 through pipelines to form an internal closed-loop passage; The absorber 4 includes a mass block 42, and a rubber bushing 41 is wrapped outside the mass block 42. As Figure 2 shown, the rubber bushing 41 can slide axially in the vibration absorption cavity without resistance. The outer walls of the end rubber bladder 3 and the tail rubber bladder 5 are both made of elastic rubber material. The end rubber bladder 3 and the tail rubber bladder 5 have the same volume. Each single end rubber bladder 3 and tail rubber bladder 5 can move the absorber 4 to one end of the vibration absorption cavity by introducing damping fluid 7. The volume of the end rubber bladder 3 and the tail rubber bladder 5 increases or decreases according to the amount of damping fluid 4 filled in, generating a pressure to support the absorber 4.

[0027] A plurality of acceleration sensors 2 are arranged along the axial direction of the boring bar. The acceleration sensors 2 are arranged axially close to the vibration absorption cavity; The abscissa positions of the acceleration sensors 2 are successively x i (i = 1, 2, ……, n). All the acceleration sensors 2 are connected to a controller 7. The controller 7 collects and calculates the root mean square values of the vibration accelerations of each acceleration sensor 2, which are successively marked as y i (i = 1, 2, ……, n). The controller performs polynomial fitting on the root mean square values (x i , y i ) at each position along the axial direction to obtain the vibration mode curve y = y(x) of the boring bar 1, and then obtains the maximum position of the amplitude of the boring bar 1, which is marked as x max ;

[0028] The controller 7 drives the gear pump 8 to work, driving the damping fluid 6 to flow between the end rubber bladder 3 and the tail rubber bladder 5. When the damping fluid flows from the end rubber bladder 3 to the tail rubber bladder 5, the tail rubber bladder 5 expands and the end rubber bladder 3 shrinks. The absorber 4 moves towards the end of the vibration absorption cavity under the thrust of the tail rubber bladder 5. Conversely, the absorber moves towards the tail of the vibration absorption cavity.

[0029] A working method of a vibration-damping boring bar with an online adjustable absorber position is as follows:

[0030] After the boring bar 1 starts working, under the action of an external excitation, the absorber 4 vibrates, and then drives the end rubber bladder 3 and the tail rubber bladder 5 to vibrate together. The damping fluid 6 dissipates the vibration energy through the damping effect;

[0031] The controller 7 starts a plurality of acceleration sensors 2 arranged along the axial direction of the boring bar. The horizontal coordinate positions of the acceleration sensors 2 are x i (i=1, 2, ..., n), the vibration state of the boring bar 1 is collected in real time by the acceleration sensor 2, and the vibration state of the boring bar 1 is sent to the controller 7, and the controller 7 collects and calculates the mean square value of the vibration acceleration of each acceleration sensor 2, which is marked as y i (i=1,2,……,n), the controller 7 calculates the mean square value (x i ,y i ) is fitted with a polynomial to obtain the vibration mode curve y=y(x) of the boring bar 1, and then the maximum position x of the vibration amplitude of the boring bar 1 is calibrated. max ;

[0032] The controller 7 adjusts the volume ratio of the damping liquid 4 in the end rubber liquid bag 3 and the tail rubber liquid bag 5 by controlling the gear pump 8, so as to move the vibration absorber 4 to the maximum vibration position x of the boring bar corresponding to the vibration absorption cavity. max The position of the vibration absorber 4 is set to achieve the best vibration absorption effect;

[0033] When the boring bar 1 changes the cutting scheme or cutting object, the controller 7 quickly regains the maximum position x of the current amplitude of the boring bar 1 through the acceleration sensor 2. max , then the controller 7 re-controls the gear pump 8 to change the position of the vibration absorber 4 to the maximum position x of the current amplitude of the boring bar 1 max The corresponding position in the vibration absorption cavity.

[0034] When the damping fluid 6 flows from the end rubber sac 3 to the tail rubber sac 5, the tail rubber sac 5 expands and the end rubber sac 3 shrinks. The vibration absorber 4 moves toward the end of the boring bar 1 under the thrust of the tail rubber sac 5. Conversely, the vibration absorber 4 moves toward the tail of the boring bar 1. Assuming that the initial position of the vibration absorber is x0 and the diameter of the damping fluid 6 is d, the distance to be moved is Δx = |x0-x max |, the amount of damping liquid 4 between the end rubber liquid bag 3 and the tail rubber liquid bag 5 The controller 7 is used to adjust the position of the vibration absorber 4 in real time so that it is always located at the maximum amplitude position x of the boring bar. max At the corresponding vibration absorbing cavity, the vibration absorber 4 can exert a better vibration absorbing effect, reduce the vibration during part processing, and improve the quality of the processed surface.

Claims

1. A damping boring bar with an on-line adjustable absorber position, characterized in that: It includes a vibration absorption cavity arranged inside the boring bar (1). An absorber (4) is provided inside the vibration absorption cavity. The vibration absorption cavity is divided into a front cavity and a rear cavity by the absorber (4). An end rubber bladder (3) is provided in the front cavity, and a tail rubber bladder (5) is provided in the rear cavity. The absorber (4) is arranged between the end rubber bladder (3) and the tail rubber bladder (5). The end rubber bladder (3) has an opening at the front end, and the tail rubber bladder (5) has an opening at the tail end. The openings are both connected to a gear pump (8) through pipelines to form an internal closed-loop passage; damping fluid (6) controlled by the gear pump (8) is filled in the end rubber bladder (3) and the tail rubber bladder (5), and the pressure oil in the end rubber bladder (3) and the tail rubber bladder (5) is changed by the gear pump (8). Multiple acceleration sensors (2) are arranged along the axial direction of the boring bar. The abscissa positions of the acceleration sensors (2) are successively x i (i = 1, 2, ……, n). All acceleration sensors (2) are connected to the controller (7). The controller (7) collects and calculates the mean square values of the vibration accelerations of each acceleration sensor (2), which are successively marked as y i (i = 1, 2, ……, n). The controller performs polynomial fitting on the mean square values (x i , y i ) at various positions along the axial direction to obtain the vibration mode curve y = y(x) of the boring bar (1), and then obtains the position with the maximum amplitude of the boring bar (1), which is marked as x max ; The controller (7) drives the gear pump (8) to work, driving the damping fluid (6) to flow between the end rubber bladder (3) and the tail rubber bladder (5). When the damping fluid flows from the end rubber bladder (3) to the tail rubber bladder (5), the tail rubber bladder (5) expands and the end rubber bladder (3) shrinks. The absorber (4) moves towards the end of the vibration absorption cavity under the thrust of the tail rubber bladder (5). On the contrary, the absorber moves towards the tail of the vibration absorption cavity.

2. The vibration-damping boring bar with an online adjustable absorber position according to claim 1, characterized in that: The absorber (4) includes a mass block (42). The outside of the mass block (42) is wrapped with a rubber bushing (41). The rubber bushing (41) can slide axially in the vibration absorption cavity without resistance.

3. The vibration-damping boring bar with an online adjustable absorber position according to claim 1, characterized in that: The outer walls of the end rubber bladder (3) and the tail rubber bladder (5) are both made of elastic rubber material. The end rubber bladder (3) and the tail rubber bladder (5) have the same volume. Each single end rubber bladder (3) and tail rubber bladder (5) can move the absorber (4) to one end of the vibration absorption cavity by introducing the damping fluid (6). The volume of the end rubber bladder (3) and the tail rubber bladder (5) increases or decreases according to the amount of the damping fluid (6) filled in, generating pressure to support the absorber (4).

4. The vibration-damping boring bar with an online adjustable absorber position according to claim 1, characterized in that: The acceleration sensor (2) is arranged axially close to the vibration absorption cavity.

5. A working method of a vibration-damping boring bar with an online adjustable absorber position according to any one of claims 1-4, characterized in that The steps are as follows: After the boring bar (1) starts to work, under the action of external excitation, the absorber (4) vibrates, and then drives the end rubber bladder (3) and the tail rubber bladder (5) to vibrate together. The damping fluid (6) dissipates the vibration energy through the damping effect. Start a plurality of acceleration sensors (2) arranged axially along the boring bar through the controller (7). The abscissa positions of the acceleration sensors (2) are successively x i (i = 1, 2, ……, n). Use the acceleration sensors (2) to collect the vibration state of the boring bar (1) in real time, and send the vibration state of the boring bar (1) to the controller (7). The controller (7) collects and calculates the mean square value of the vibration acceleration of each acceleration sensor (2), and successively marks them as y i (i = 1, 2, ……, n). The controller (7) performs polynomial fitting on the mean square values (x i , y i ) along the axis to obtain the vibration mode curve y = y(x) of the boring bar (1), and then calibrate the maximum position x max ; The controller (7) adjusts the volume ratio of the damping liquid (6) in the end rubber bladder (3) and the tail rubber bladder (5) by controlling the gear pump (8), so as to move the shock absorber (4) to the position x corresponding to the maximum vibration of the boring bar in the shock absorption cavity, so that the shock absorber (4) obtains the best shock absorption effect; max At this position, the shock absorber (4) can achieve the best shock absorption effect; When the boring bar (1) changes the cutting scheme or the cutting object, the controller (7) quickly obtains the maximum position x of the current amplitude of the boring bar (1) again through the acceleration sensor (2). max After that, the controller (7) re-controls the gear pump (8) to change the position of the vibration absorber (4) to the maximum position x of the current amplitude of the boring bar (1). max The corresponding position in the vibration absorption cavity.

6. The working method according to claim 5, characterized in that: After the damping fluid (6) flows from the end rubber bladder (3) to the tail rubber bladder (5), the tail rubber bladder (5) expands and the end rubber bladder (3) shrinks. The absorber (4) moves towards the end of the boring bar (1) under the thrust of the tail rubber bladder (5). On the contrary, the absorber (4) moves towards the tail of the boring bar (1).

7. The working method according to claim 6, characterized in that: Let the initial position of the vibration absorber be \(x_0\), and the diameter of the damping liquid (6) be \(d\). Then the distance \(\Delta x\) that needs to be moved is \(\Delta x = |x_0 - x|\). max The preparation amount of the damping liquid (6) between the end rubber liquid chamber (3) and the tail rubber liquid chamber (5). It is adjusted in real time by the controller (7) so that the position of the vibration absorber (4) is always at the position \(x\) where the amplitude of the boring bar is the largest, max at the corresponding vibration absorption cavity, so that the vibration absorber (4) can achieve a better vibration absorption effect, reduce the vibration during part processing, and improve the quality of the machined surface.

Images