JP2018192532A - Vibration control device and working machine - Google Patents

Abstract

To provide a vibration control device which can control vibration at a proper gain value for a cutting force.SOLUTION: The vibration control device for suppressing vibration of a cut material during working is provided that comprises: a sensor which measures vibration during working; a frequency analysis processing part which analyses a frequency and a phase of vibration based on a measurement signal from the sensor; a drive output generating part which generates a driving signal having a phase opposite to that of the measured vibration; a drive part comprising an actuator which is fitted to the cut material and is driven by the driving signal; a cutting force calculation part which calculates a cutting force by a signal from a working machine; and a gain setting part which sets a gain adapted to the cutting force. The drive output generating part adjusts a gain of the driving signal by the set gain.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a vibration damping device and a processing machine including the vibration damping device.

  In a processing machine, vibration is generated due to a reaction force or the like when a work material is processed with a tool. In order to prevent deterioration of processing quality due to vibration, a vibration damping device that suppresses vibration is provided.

  An example of a vibration damping device in a processing machine is described in Japanese Patent Application Laid-Open No. 2014-184548 (Patent Document 1). This gazette states that "the vibration damping device is operated by a weight provided on the ram, an actuator that vibrates and displaces the weight, a displacement meter that measures the relative displacement between the ram and the weight, a control circuit unit, and a control circuit unit. A drive unit that supplies an electric current based on the control signal to the actuator, the control circuit unit configured to set a control constant according to the natural frequency of the ram corresponding to the position of the ram, And a calculation unit (a gain setting unit and a phase shift filter) for setting the gain and phase of the control signal based on the control constant and the relative displacement while increasing the dynamic rigidity when the main shaft holding member protrudes greatly. , Exhibit a damping effect over the entire stroke of the spindle holding member ”(see summary).

JP 2014-184548 A

  Patent Document 1 describes a device that suppresses vibration of a ram on the tool side of a processing machine. At the tip of the ram to which the tool is attached, there is a weight and an actuator that drives the weight. The method of canceling is taken. In addition, for the forced vibration that occurs when the tool strikes the workpiece periodically, the acceleration is measured with the provided accelerometer, and the actuator is controlled by setting a specific control constant to control the vibration of the ram. Suppress. However, the apparatus of Patent Document 1 considers only the natural frequency of the ram and the forced vibration in which the tool strikes the workpiece, and does not consider other vibration factors. In particular, the vibration of the work material directly affects the machining accuracy, but the vibration of the work material is not taken into consideration. In addition, since the cutting force during processing is not taken into consideration, it is difficult to drive the actuator with an appropriate inertial force with respect to the cutting force.

  Conventionally, in order to suppress the vibration of the work material, the fixing method is mainly used, and it may not be able to actively respond to a decrease in rigidity due to the deformation of the shape due to processing or a change in processing conditions. It was a problem.

  The present invention provides a vibration damping device capable of controlling vibration with an appropriate gain value with respect to cutting force.

  An example of the vibration damping device of the present invention for solving the above problems is a vibration damping device that suppresses vibration of a workpiece being processed, the sensor for measuring vibration during processing, A frequency analysis processing unit that analyzes the frequency and phase of vibration based on a measurement signal from a sensor, a drive output generation unit that generates a drive signal having an opposite phase to the measured vibration, and a work material, A drive unit including an actuator driven by a drive signal; a cutting force calculation unit that calculates a cutting force from a signal from a processing machine; and a gain setting unit that sets a gain that matches the cutting force, and the drive output The generating unit adjusts the gain of the drive signal according to the set gain.

ADVANTAGE OF THE INVENTION According to this invention, the damping device which can control a vibration with an appropriate gain value with respect to cutting force can be provided.
Problems, configurations, and effects other than those described above will become apparent from the following description of the embodiments.

It is a figure which shows one example of the damping device of Example 1. FIG. It is a figure which shows the operation | movement flow of the damping device of Example 1. FIG. It is a figure which shows the flow of the signal matched with the structure of the control part of a damping device. It is a figure which shows the relationship between a gain and cutting force. It is an example of the external view of the drive part of a damping device. It is an example inside the drive part of a damping device. It is an example of sectional drawing of the drive part of a damping device. It is a figure which shows one example of the damping device of Example 2. FIG.

  Embodiments of the present invention will be described below with reference to the drawings. Note that, in the drawings for explaining the embodiments, the same constituent elements are given the same names and symbols as much as possible, and the repeated explanation thereof is omitted.

  In this embodiment, an example of a vibration damping device that suppresses vibration during machining will be described.

  FIG. 1 is a diagram illustrating a configuration of a vibration damping device that suppresses vibration during processing according to the first embodiment. It is comprised from the processing machine 1 and the damping device 18 which suppresses the vibration in process.

  In the processing machine 1, the workpiece 6 is processed into a desired shape by holding the cutting tool 5 with the main shaft 4 and rotating the main shaft 4. At this time, the servo amplifier 8 controls the spindle motor 7 according to a command from the NC device 9 in which the NC program is stored. Thereby, the main shaft 4 is rotated at the rotational speed as commanded.

  In this embodiment, the cutting force is calculated based on the NC command value of the processing machine 1, and the vibration damping device is driven. The vibration damping device 18 includes a drive unit 2, a control unit 3, and an input unit 15. The drive unit 2 includes an actuator 16 and a sensor 17. The drive unit 2 is fixed to a work material 6 installed in the processing machine. The drive unit 2 may be fixed to a part other than the work material 6 as long as it vibrates. For example, a jig for fixing the work material 6 or a table of a processing machine may be used. Vibration during processing is measured by the sensor 17 of the drive unit 2 and input to the control unit 3.

  The control unit 3 generates a signal for suppressing vibration, and drives the actuator 16 of the driving unit 2 by the generated signal. The control unit 3 performs frequency analysis on the vibration data being processed measured by the sensor 17 of the drive unit 2 and generates a drive signal for driving the actuator 16 based on the frequency analysis result. A generation unit 14 is provided. Further, the control unit 3 obtains a cutting force during processing and sets an optimum gain, a processing condition extraction unit 10 that extracts a processing condition from the NC device 9 of the processing machine 1, and a cutting force from the extracted processing condition. Is provided with a cutting force calculation unit 11 for calculating the gain and a gain setting unit 12 for calculating a gain suitable for the cutting force. In addition, the control unit 3 includes an input unit 15 that inputs data and the like.

FIG. 2 shows an operation flow of the vibration damping device 18 of the first embodiment, and FIG. 3 shows a signal flow associated with the configuration of the control unit 3.
A case will be described in which machining starts in step 30 and vibration occurs during machining.
In step 31, vibration is measured by the sensor 17 of the drive unit 2. The measured vibration signal is input to the frequency analysis processing unit 13 of the control unit 3.
In step 32, the frequency analysis processing unit 13 analyzes the frequency and phase of the measured data.

  In step 34, the machining condition extraction unit 10 extracts parameters necessary for calculating the cutting force from the signal of the NC device 9. The parameters include tool diameter, tool rotation speed, tool feed speed, and the like. For example, the position information of the tool can be grasped by reading the position information of the X axis, the Y axis, and the Z axis from the NC program. Tool information can be determined from the command number for automatic tool change in the NC program. Alternatively, tool information may be input through the input unit 15. The tool information includes the tool diameter, the number of blades, and the twist angle. Alternatively, the tool data 20 may be stored in the control unit. In addition to the tool, the input unit 15 may input the material of the work material and the shape of the workpiece. By inputting the material of the work material, the cutting force can be calculated with higher accuracy. Further, by inputting the shape of the workpiece, the position of the tool and the currently processed portion can be obtained more accurately and safely.

Subsequently, in step 35, the cutting force is calculated. The cutting force is calculated by the cutting force calculation unit 11 of the control unit 3.
In step 36, a gain that matches the calculated cutting force is set by the gain setting unit 12, and the magnitudes of the current and voltage input to the actuator 16 are determined. The gain setting unit 12 stores data 21 storing the relationship between the cutting force and an appropriate gain value, and the gain is set based on the stored data.

In step 33, a drive signal for the actuator 16 is generated by the drive output generator 14. Based on the frequency and phase of the vibration analyzed in step 32, a drive signal for driving the actuator 16 having a phase opposite to that of the measured vibration is created. Further, the gain of the actuator drive signal is adjusted to an appropriate gain based on the gain set in step 36.
In step 37, the generated drive signal is input to the actuator 16, and the actuator 16 is driven. The actuator 16 vibrates with an appropriate gain in the opposite phase to the work material 6, thereby canceling the vibration of the work material 6 and suppressing the vibration during processing.

  FIG. 4 is a graph showing the relationship between cutting force and gain. When an appropriate gain setting value is obtained like a graph with respect to the cutting force generated during machining, the relationship between the cutting force and the gain can be shown linearly on a logarithmic graph. Here, the example which processed SS400 material with the 4 blade end mill of diameter 25mm is shown. This data may correspond to the data 21 of the gain setting unit 12. From this graph, the gain corresponding to the cutting force calculated in real time is obtained.

  In FIG. 5, an example of the external view of the drive part 2 of the damping device 18 is shown. The drive unit 2 includes a fixed plate 51 and a housing 50, and a structure such as the actuator 16 is built in the housing 50. FIG. 6 shows an example of an external view of the drive unit 2 with the housing 50 removed. The actuator 16 is installed below the fixed plate 51.

  FIG. 7 shows a cross-sectional view of the drive unit 2. A rod 53 is fixed at the center of the drive unit 2. The actuator 16 is installed using the rod 53 as a guide. The actuator 16 includes a mover 16a and a stator 16b, and the mover 16a is driven up and down along a rod 53 passed through the center. A viscoelastic body 55 is installed on the top of the movable element 16a. The viscoelastic body 55 is directly fixed to the rod 53 and functions to keep the movable element 16a of the actuator 16 within a certain range so that it does not collide with the fixed plate 51. Also, it functions to vibrate the mover 16a. When the viscoelastic body 55 is weakly fixed to the rod 53, a fixing jig 54 may be used to fix the viscoelastic body 55 to the actuator 16 with certainty.

  Here, it is assumed that the actuator 16 is driven by electromagnetic force. At this time, the coil 56 is wound around the stator 16 b, and a current flows through the coil 56 by voltage and current control from the control unit 3. When the mover 16 a is a magnet, a force is generated in the direction in which the mover 16 a moves up and down due to the relationship between the magnetic field generated by the magnet and the current flowing through the coil 56. Based on this principle, the mover 16a is driven in the vertical direction to cancel the vibration of the work material 6, and the vibration is suppressed. At the lower end of the drive unit 2, there is a vibration damping device fixing unit 59 that is directly installed on the work material 6. The damping device fixing portion needs to be fixed to the work material 6 to such an extent that it does not shift due to vibration during processing. Fixing with magnets or fixing with screws may be used. Since the sensor 17 needs to directly measure the vibration of the work material 6, for example, as shown in FIG. The sensor 17 may be an acceleration sensor or a position sensor, for example.

  According to the present embodiment, it is possible to automatically optimize vibration suppression for a plurality of different machining objects and machining processes, and it is possible to improve machining accuracy and efficiency. In addition, by predicting the cutting force during machining and setting the gain value to drive the actuator from the cutting force, it is possible to respond to changes in the natural frequency due to deformation of the shape due to machining and changes in machining conditions. In particular, the vibration of the work material being processed can be suppressed. In addition, since the drive unit of the vibration damping device is attached to the work material and the actuator is driven by the drive signal created based on the vibration signal detected by the sensor, the vibration of the work material can be satisfactorily suppressed. it can.

FIG. 8 shows an example of a vibration damping device that calculates the cutting force based on the output value of the force sensor according to the second embodiment.
A force sensor 80 is attached to the main shaft 4 of the processing machine 1. The force sensor 80 directly measures the cutting force during processing. The measurement result is input to the cutting force calculation unit 11 of the control unit 3 of the vibration damping device 16 and converted into a form that can be compared with the gain. For example, when the measurement signal has a lot of noise, noise cut filter processing using a high-pass filter, a low-pass filter, or the like may be performed. Further, the force sensor 80 may be attached to the work material 6 instead of the main shaft 4. Subsequent processing methods such as gain setting and drive signal generation are the same as in the first embodiment. Here, a strain gauge or a load cell may be used as the force sensor.

  According to the present embodiment, in addition to the effects of the first embodiment, vibration control is performed by directly measuring the cutting force being processed by the force sensor, so that accurate vibration suppression can be performed with a simple configuration.

The processing machine of the present invention includes the vibration damping device of each of the above embodiments.
In addition, a processing machine is good also as a product which is equipped with the damping device integrally, and you may combine a damping device with the existing processing machine which is not equipped with the damping device later.

  In addition, this invention is not limited to an above-described Example, Various modifications are included. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

DESCRIPTION OF SYMBOLS 1 ... Processing machine, 2 ... Drive part, 3 ... Control part, 4 ... Main axis | shaft, 5 ... Cutting tool, 6 ... Work material,
DESCRIPTION OF SYMBOLS 9 ... NC apparatus, 10 ... Machining condition extraction part, 11 ... Cutting force calculation part, 12 ... Gain setting part,
13 ... Frequency analysis processing unit, 14 ... Drive output generation unit, 15 ... Input unit,
16a ... mover, 16b ... stator, 16 ... actuator, 17 ... sensor,
18 ... damping device, 53 ... rod, 55 ... viscoelastic body, 56 ... coil, 80 ... force sensor.

Claims (8)

A vibration damping device that suppresses vibration of a work material being processed,
A sensor for measuring vibration during processing;
A frequency analysis processing unit that analyzes the frequency and phase of vibration based on a measurement signal from the sensor;
A drive output generator that generates a drive signal having a phase opposite to that of the measured vibration;
A drive unit that is attached to the work material and includes an actuator that is driven by the drive signal;
A cutting force calculation unit for calculating cutting force from a signal from the processing machine;
A gain setting unit that sets a gain that matches the cutting force;
The drive output generation unit adjusts the gain of the drive signal according to the set gain. The vibration damping device according to claim 1,
A drive unit configured with the actuator and the sensor, a control unit configured with the cutting force calculation unit, the gain setting unit, and the frequency analysis processing unit, and an input unit for inputting machining conditions. Damping device. The vibration damping device according to claim 1,
The vibration control device, wherein the cutting force calculation unit calculates the cutting force from NC data of a processing machine, a tool diameter input from the input unit, and a physical property value of a work material. The vibration damping device according to claim 1,
A vibration damping device comprising a machining condition extraction unit that extracts a machining condition from an NC device of a processing machine. The vibration damping device according to claim 1,
It has a force sensor attached to the spindle of the motor or work material,
The vibration control device, wherein the cutting force calculation unit calculates a cutting force based on a signal detected by the force sensor. The vibration damping device according to claim 1,
The said gain setting part sets a gain from the relationship between the cutting force and gain value which were stored beforehand, The damping device characterized by the above-mentioned. The vibration damping device according to claim 1,
The drive unit includes an actuator propelled in a certain direction, a viscoelastic body that limits a movable range of the actuator, a rod that guides the actuator, and a sensor that measures vibration during processing. Damping device.   A processing machine provided with the damping device of any one of Claims 1-7.

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