JP6452898B1 - Spindle unit runout detector - Google Patents

Abstract

For the purpose of obtaining a spindle unit run-out detecting device capable of detecting the run-out of the spindle unit from the start of operation to the start of cutting, the tool has a spindle unit that can be attached and detached, and the spindle unit has a tool Is a spindle unit center runout detection device (1) connected to a servo motor drive device (7) of a machine tool that drives a tool by a spindle motor (2) to process a workpiece when the tool is mounted And a spindle unit runout determination unit (9) for judging the runout of the spindle unit based on the detection result of the servo motor detector (6) that moves the spindle unit in the linear movement direction at the time of removal. To do.

Description

  The present invention relates to a spindle unit runout detection device connected to a machine tool.

  2. Description of the Related Art Conventionally, a machine tool is known in which a cutting tool is supported on a rotatable spindle unit, the cutting tool and a workpiece are relatively moved, and the workpiece is processed by the cutting tool. In such a machine tool, when the runout occurs in the spindle unit, the runout occurs at the tip of the cutting tool as the spindle motor rotates. In addition, vibration may occur due to the core runout of the spindle unit. Due to the whirling or vibration of the tip of the cutting tool, problems such as a decrease in the finishing accuracy of the machined surface, rapid wear of the cutting tool, and chipping of the cutting tool occur. The runout of the core refers to a phenomenon in which the tip of the cutting tool attached to the end of the spindle unit sways during rotation. Causes of center run-out include spindle unit abnormalities such as spindle unit imbalance and bearing abnormality, spindle motor abnormality, tool unbalance, and tool chucking failure.

  Patent Document 1, which is an example of the prior art, aims to detect vibration associated with the rotation of a tool of a machine tool. An acceleration sensor unit is provided in the spindle unit, and vibration acceleration of the spindle unit is detected. A technique for determining the unbalance of a tool by comparing the value with a threshold value is disclosed.

Japanese Patent Laid-Open No. 03-228542

  However, according to the above-described prior art, even if the acceleration sensor unit is provided in the spindle unit, only the tool unbalance, which is one of the factors of core runout, can be detected. There was a problem that it could not be determined.

  The present invention has been made in view of the above, and without adding a special device such as an acceleration sensor unit to the spindle unit, a plurality of runouts of the spindle unit can be performed between the start of operation and the start of cutting. It is an object of the present invention to obtain a spindle unit run-out detecting device capable of determining a factor.

In order to solve the above-described problems and achieve the object, the present invention has a spindle unit in which a tool is detachable, the tool is mounted on the spindle unit, and the tool is driven by a spindle motor to process a workpiece. a spindle unit runout detecting device connected to the servo motor driving device for a machine tool for performing, in a state in which the tool is remove the state and the tool is mounted, linearly moving direction of the spindle unit the basis of the detection result and the rotation frequency of the spindle motor of the detector of the servo motor for moving said determining whether the runout of the spindle unit, the said frequency component of the loop obtained from the servo motor drive spindle motor by comparing the rotational frequency factors of runout is, shake spindle unit core and determines whether the abnormality of the spindle unit or spindle motor Characterized in that it comprises a tough.

  The spindle unit center run-out detecting device according to the present invention has an effect that it can detect the run-out of the spindle unit from the start of operation to the start of cutting.

The block diagram which shows the periphery structure connected to the structure of the spindle unit core run-out detection apparatus which concerns on embodiment, and a spindle unit core run-out detection apparatus Side view showing a specific peripheral configuration connected to the spindle unit core runout detection device shown in FIG. The block diagram which shows the detailed example of 1 structure of the spindle unit core run-out detection apparatus which concerns on embodiment The flowchart which shows operation | movement of the spindle unit core run-out detection apparatus shown in FIG. The figure which shows the general structure of the hardware which implement | achieves the spindle unit core run-out detection apparatus shown in FIG. Diagram showing droop before and after tool installation phase change with the horizontal axis as the spindle motor phase and the vertical axis as the servo motor droop

  Hereinafter, a spindle unit center runout detection apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment.
FIG. 1 is a block diagram showing a configuration of a spindle unit center runout detection apparatus according to an embodiment of the present invention and a peripheral configuration connected to the spindle unit core runout detection apparatus. A spindle unit center runout detection apparatus 1 shown in FIG. 1 includes a spindle unit abnormality detection unit 8 and a spindle unit center runout determination unit 9. FIG. 1 shows a spindle motor 2 on the spindle unit side, a spindle motor detector 3, a spindle motor drive device 4 connected to the spindle motor 2 and the spindle motor detector 3, a servo motor 5 on the servo axis side, A servo motor detector 6 and a servo motor drive device 7 connected to the servo motor 5 and the servo motor detector 6 are shown. The spindle unit abnormality detection unit 8 is connected to the spindle motor driving device 4 and the servo motor driving device 7. The spindle unit center runout determination unit 9 is connected to the spindle unit abnormality detection unit 8 and can output the determination result to the outside. The spindle motor detector 3 outputs the detection result of the spindle motor 2 to the spindle motor driving device 4. The servo motor detector 6 outputs the detection result of the servo motor 5 to the servo motor driving device 7.

  FIG. 2 is a side view showing a specific peripheral configuration connected to the spindle unit core runout detection apparatus 1 shown in FIG. FIG. 2 shows a spindle motor 2 that drives the spindle unit, a spindle motor detector 3, a spindle motor drive device 4, a servo motor 5 that drives the servo shaft, a servo motor detector 6, and a servo motor drive device. 7, a ball screw 10 connected to the servo motor 5, a nut 11 assembled to the ball screw 10, a chuck 12 connected to the spindle motor 2, and a cutting connected to the spindle motor 2 via the chuck 12. And a tool 13 which is a tool. The spindle motor 2, the spindle motor detector 3, the nut 11, and the chuck 12 constitute a spindle unit that is a movable part. The movable direction of the movable part is the axial direction of the ball screw 10, and the degrees of freedom other than the movable direction of the movable part are restricted. When the spindle unit is unbalanced, when the tool 13 is unbalanced or when there is a chucking failure of the tool 13, a swing occurs, and the reaction force is generated by the servo motor drive device. 7 is obtained as a droop waveform. Droop refers to a tracking error in servo control. In the following description, the droop from the servo motor driving device is also referred to as a servo motor droop.

  FIG. 3 is a block diagram illustrating a detailed configuration example of the spindle unit core runout detection apparatus 1 illustrated in FIG. 1. 3 includes a droop acquisition unit 21, a frequency component analysis unit 22, a spindle motor rotation frequency acquisition unit 23, a frequency comparison unit 24, a phase comparison unit 25, and an abnormality factor determination. Part 26.

  The droop acquisition unit 21 acquires a droop from the servo motor driving device 7. The frequency component analyzer 22 analyzes the droop frequency component acquired by the droop acquisition unit 21 and outputs the droop frequency component. The spindle motor rotation frequency acquisition unit 23 acquires the rotation frequency of the spindle motor from the spindle motor drive device 4. The frequency comparison unit 24 compares the droop frequency component output from the frequency component analysis unit 22 with the rotational frequency of the spindle motor. The phase comparison unit 25 compares the droop phases of the droops acquired by the droop acquisition unit 21 a plurality of times. The abnormality factor determination unit 26 determines an abnormality factor based on the frequency comparison result output by the frequency comparison unit 24 and the phase comparison result output by the phase comparison unit 25. This determination result is output to an external output device (not shown), for example, a display device.

  The droop acquisition unit 21, the frequency component analysis unit 22, the spindle motor rotation frequency acquisition unit 23, and the frequency comparison unit 24 constitute the spindle unit abnormality detection unit 8. The abnormality factor determination unit 26 constitutes the spindle unit center runout determination unit 9.

  FIG. 4 is a flowchart showing the operation of the spindle unit center runout detection apparatus 1 shown in FIG. In FIG. 4, when the tool 13 is attached to the spindle unit, the process starts. First, the spindle motor drive device 4 rotates the spindle motor to which the tool 13 is attached (S11), and the spindle motor rotation frequency acquisition unit 23 acquires the rotation frequency of the spindle motor (S12). Next, the droop acquisition unit 21 acquires a droop from the servo motor drive device 7 (S13). The frequency component analyzer 22 analyzes the frequency component of the droop acquired in S13 (S14). Then, the frequency comparison unit 24 compares the droop frequency component analyzed in S14 with the rotational frequency of the spindle motor acquired in S12 (S15). The abnormality factor determination unit 26 determines whether or not the droop frequency component analyzed in S14 matches the rotational frequency of the spindle motor acquired in S12 from the comparison result in S15 (S16).

  Here, when the frequency component of the droop does not coincide with the rotational frequency of the spindle motor (S16: No), the abnormality factor determination unit 26 determines that the spindle unit does not run out (S17). The result is output and the process is terminated.

  If the frequency component of the droop matches the rotational frequency of the spindle motor (S16: Yes), the user removes the tool 13 from the spindle unit (S21), and the spindle motor drive device 4 is removed with the tool 13 removed. The spindle motor is rotated (S22), and the spindle motor rotation frequency acquisition unit 23 acquires the rotation frequency of the spindle motor (S23). Next, the droop acquisition unit 21 acquires the droop from the servo motor drive device 7 (S24). The frequency component analyzer 22 analyzes the frequency component of the droop acquired in S24 (S25). Then, the frequency comparison unit 24 compares the frequency component of the droop analyzed in S25 with the rotation frequency of the spindle motor acquired in S23 (S26). The abnormality factor determination unit 26 determines whether or not the droop frequency component analyzed in S25 matches the rotational frequency of the spindle motor acquired in S23 from the comparison result in S26 (S27).

  Here, when the frequency component of the droop analyzed in S25 matches the rotational frequency of the spindle motor (S27: Yes), the abnormality factor determination unit 26 has an abnormality in the spindle motor or the spindle unit has run out. It is determined that there is (S28), the determination result is output, and the process is terminated. In this case, the cause of the core runout of the spindle unit is a factor other than tool imbalance or chucking failure, for example, spindle unit abnormality such as spindle unit imbalance or bearing abnormality, and spindle motor abnormality. Presumed.

  If the frequency component of the droop analyzed in S25 does not match the rotational frequency of the spindle motor (S27: No), the tool 13 is attached to the spindle unit so as to have a phase different from the tool attachment position in S11. (S31), the spindle motor drive device 4 rotates the spindle motor with the tool 13 attached to a different phase (S32), and the spindle motor rotation frequency acquisition unit 23 acquires the rotation frequency of the spindle motor (S33). Next, the droop acquisition unit 21 acquires a droop from the servo motor drive device 7 (S34). The phase comparison unit 25 compares the amount of change between the droop phase acquired in S34 and the amount of droop acquired in S13 with the amount of change in the tool attachment phase in S13 and S34 (S35).

  Here, when the amount of change in the droop phase compared in S35 matches the amount of change in the tool attachment phase (S36: Yes), the abnormality factor determination unit 26 has an abnormality due to the unbalance of the tool 13. (S37), the determination result is output, and the process is terminated.

  If the change amount of the droop phase compared with the change amount of the tool attachment phase compared in S35 does not match (S36: No), the abnormality factor determination unit 26 determines that there is a chucking failure (S38), The determination result is output and the process is terminated.

  Here, a hardware configuration for realizing the spindle unit center runout detection apparatus 1 according to the present embodiment will be described. FIG. 5 is a diagram illustrating a general configuration of hardware that realizes the spindle unit core runout detection apparatus 1 illustrated in FIG. 3. FIG. 5 shows an IF 31, a processor 32, and a storage circuit 33 that are interfaces. The processor 32 implements the frequency component analysis unit 22, the frequency comparison unit 24, the phase comparison unit 25, and the abnormality factor determination unit 26 by executing and executing a program. The processor 32 is typically a CPU (Central Processing Unit). The storage circuit 33 stores a program to be executed by the processor 32 and stores data necessary for the processor 32 to execute and execute the program. The IF 31 is configured to realize an external input / output of the spindle unit core runout detection apparatus 1, and implements a droop acquisition unit 21 and a spindle motor rotation frequency acquisition unit 23. The abnormality factor determination unit 26 is realized by the IF 31, the processor 32, and the storage circuit 33. A plurality of IFs 31, processors 32, and storage circuits 33 may be provided.

  FIG. 6 is a diagram showing the droop before and after the tool attachment phase change, with the horizontal axis being the phase of the spindle motor and the vertical axis being the servo motor droop. The upper diagram of FIG. 6 shows the servo motor droop before the tool installation phase is changed, and the lower diagram of FIG. 6 shows the servo motor droop after the tool installation phase is changed. First, the servo motor droop is acquired before the tool mounting phase is changed, and then the tool mounting phase is changed to acquire the servo motor droop, and the relationship between the phase of the spindle motor 2 and the servo motor droop of the servo motor 5 is determined by the tool. Compare before and after changing the mounting phase. Then, the change amount of the tool attachment phase and the change amount of the droop waveform phase are compared, and if they match, it is determined that there is an abnormality due to the unbalance of the tool 13 as shown in S37 of FIG. To do. The lower diagram of FIG. 6 shows the servo motor droop after changing the tool attachment phase when the tool 13 is unbalanced.

  According to the spindle unit core runout detection apparatus described in the present embodiment, it is possible to detect the runout of the spindle unit before the start of cutting. Therefore, it is possible to prevent a reduction in finishing accuracy of the work surface of the workpiece, rapid wear of the tool, and tool breakage.

  The configuration described in the above embodiment shows an example of the contents of the present invention, and can be combined with another known technique, and can be combined with other configurations without departing from the gist of the present invention. It is also possible to omit or change the part.

  1 Spindle unit runout detector 2 Spindle motor 3 Spindle motor detector 4 Spindle motor drive 5 Servo motor 6 Servo motor detector 7 Servo motor drive 8 Spindle unit abnormality detection unit 9 Spindle unit Center runout determination unit, 10 ball screw, 11 nut, 12 chuck, 13 tool, 14 spindle unit, 21 droop acquisition unit, 22 frequency component analysis unit, 23 spindle motor rotation frequency acquisition unit, 24 frequency comparison unit, 25 phase comparison unit , 26 Abnormal factor determination unit, 31 IF, 32 processor, 33 storage circuit.

Claims (3)

Spindle unit runout detection connected to a servo motor drive device of a machine tool that has a spindle unit to which a tool is detachable, attaches the tool to the spindle unit, and drives the tool by a spindle motor to process a workpiece A device,
In a state in which the tool is remove the state and the tool is mounted, based on the detection result and the rotation frequency of the spindle motor of the detector of the servo motor for moving the spindle unit into a linear moving direction, said spindle The presence or absence of center runout of the unit is determined, the frequency component of the droop obtained from the servo motor drive device is compared with the rotation frequency of the spindle motor, and the cause of the runout is an abnormality of the spindle unit or the spindle motor. A spindle unit center run-out detecting device comprising a spindle unit center run-out judging unit for judging whether or not . The spindle unit center run-out determination unit compares the droop frequency component acquired from the servo motor driving device with the rotation frequency of the spindle motor, and determines whether or not the spindle unit has run-out. Item 2. The spindle unit core runout detection device according to item 1. The spindle unit runout determination unit
Based on the amount of change in the phase of the droop and the amount of change in the phase of attachment of the tool in a plurality of states in which the attachment phase of the tool is different, the cause of the core runout is the unbalance of the tool or the tool 3. The spindle unit center runout detection device according to claim 2 , wherein it is determined whether the chucking is defective.

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