JPH0569657B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a failure prediction device used to predict failure of a spindle device in a machine tool.

<Prior art> In machine tools such as machining centers, the main shaft is rotatably supported by bearings, and this main shaft is connected to the output shaft of a main shaft motor via a gear mechanism, thereby commanding the main shaft. It rotates at the specified speed.

In such spindle devices, if the bearings wear out or the gears become loose due to long-term use, abnormal vibrations will occur in the spindle, and if this exceeds the allowable value, machining accuracy will deteriorate, and furthermore, the spindle may seize. This may lead to serious malfunction. However, in the past, no device was provided that could predict such a failure of the main shaft.

<Problems to be Solved by the Invention> As described above, in the conventional equipment, failure of the spindle cannot be predicted, so a major failure occurs in the bearing that supports the spindle and the spindle drive system during operating hours, making machining impossible. There were problems that had a significant impact on the production schedule, such as processing line stoppages.

<Means for Solving the Problems> In view of the problems of the conventional art, the present invention makes it possible to predict failures in the spindle device, and it is possible to predict the failure of the spindle device by adjusting the vibration value caused by the rotation of the spindle and the spindle drive motor. a detector for detecting at least one of the flowing current values; a normal value storage means for storing the value detected by the detector when the main shaft is rotated under normal no-load conditions immediately after assembly; failure prediction instructing means for instructing execution of prediction; and upon receiving the command from the failure prediction instructing means, the main shaft is configured to cause the main shaft to perform the same operation as when the normal value is stored by the normal value storage means. a rotation command means for driving a spindle drive motor in a no-load state, and a value detected by the detector while the spindle drive motor is rotating based on a command from the rotation command means; The present invention is characterized in that a comparison means is provided for comparing the magnitude of the value in a normal no-load state stored in the normal value storage means, and a failure of the spindle device is predicted based on the comparison result by the comparison means. It is something.

<Function> The detector detects at least one of the vibration value generated by the rotation of the spindle in a normal state immediately after assembly and the current value flowing through the spindle drive motor, and stores the detected value in the normal value storage means. Then, based on a command from the failure prediction instructing means, the rotation command means periodically detects the value when the main shaft is rotated in the same way as when the normal value is stored, using the detector. This detected value is compared with a normal value.

This allows workers to accurately grasp the extent to which the magnitude of vibration generated in the spindle device has increased compared to normal times, allowing early detection of wear on the spindle bearings and predicting failures. .

<Embodiment> In FIG. 1, reference numeral 10 denotes a spindle device of a machine tool, in which a spindle 11 is rotatably supported by a spindle head main body 13 via a pair of bearings 12, 12. and,
The main shaft 11 is connected to the output shaft of a main shaft driving motor 16 via a gear mechanism 15 that can change the reduction ratio. Further, on the back side of the spindle head body 13, there is a vibration detector 1 for detecting vibrations generated in the spindle head body 13.
7 is installed.

On the other hand, 20 is a numerical control device, and 21 is a sequence control device. In addition to the numerical control program for machining, the numerical control program for failure prediction shown in FIG. 4 is stored in the memory of the numerical control device 20. ing. Then, the numerical control device 20 selectively executes a numerical control program for machining or a numerical control program for failure prediction in response to a command from the sequence control device 21.

The numerical control device 20 also includes a rotation speed control device 2 that controls the rotation speed of the main shaft drive motor 16.
2 is connected, the S code included in the numerical control program is read by the numerical control device 20, the information of this S code is output to the rotation speed control device 22, and then the sequence control device 2
When a spindle rotation command is supplied from 1, the spindle drive motor 16 is rotated at a speed instructed by the S code. Furthermore, a current detector 23 is provided between the rotational speed control device 22 and the main shaft driving motor 16 to detect the magnitude of the current flowing through the main shaft driving motor 16.

30 is a personal computer programmed to display the vibration of the spindle head body 13 detected by the vibration detector 17 and the drive current value of the spindle motor 16 detected by the current detector 23; The outputs of the vibration detector 17 and the current detector 23 are connected to the amplifiers 25a and 25b and the AD converters 26a and 2
6b. In the memory of this personal computer 30, a program for inputting setting values shown in FIG. 2 and a program for monitoring shown in FIG. 3 are stored. Keyboard 3 of personal computer 30
When the command "VS" to input the vibration setting value is keyed in by 0a, the value input following "VS" is set to the setting vibration value Sv by the process shown in Fig. 2a.
(40), and when the command "IS" for inputting the current setting value is keyed in, the value input following "IS" is stored as the setting current value Si by the process shown in FIG. 2b ( 41).

On the other hand, when an M code M40 instructing the start of monitoring is supplied from the numerical control device 20 via the sequence control device 21, the personal computer 30 executes the process shown in FIG. 3, and first,
The process of displaying only fixed parts such as frames and titles on the monitor screen shown in Figure 5 (50) and the process of clearing the maximum values Dv ₀ and Di ₀ in the buffer to zero (51)
I do. Then, after this, the sequence control device 2
The monitor routine of steps (52) to (61) is repeatedly executed until the code M02 indicating the end of the program is output from the numerical control device 20 via step 1.

In this monitor routine, the AD converter 26a,
The signal v representing the magnitude of vibration outputted from 26b and the current value i are read (52), and it is determined whether the read values are larger than the buffers Dv ₀ and Di ₀ (53), (56), if large,
v and i are set as maximum values Dv ₀ and Di ₀ (55), (57). Then, set the maximum value Dv ₀ and Di ₀
By dividing by Sv and Si, respectively, the relative magnitudes DDv and DDi of the maximum values Dv ₀ and Di ₀ with respect to the set values Sv and Si are calculated (58). Then, in order to display a bar graph corresponding to the size of DDv and DDi on the CRT screen, the length of the bar graph on the screen is calculated (60), and the bar graph 31a of this calculated length is , 31b on the CRT screen (62).

Next, the operation of predicting a failure in the above device will be explained.

First, when the assembly of the machine is completed, the main shaft 11 is rotated at a set speed in a no-load state, and the output values of the AD converters 26a and 26b at this time are the above-mentioned "VS",
Input using the “IS” command. This results in
The personal computer 30 uses the processing shown in FIG.
Register as Si in a non-volatile storage area.

After this, after the machine is installed in the customer's factory,
Periodically press the fixed predictive operation button 2 on the operation panel 29.
Press 9a to command failure predictive operation.

When the failure prediction operation button 29a is pressed, a program selection command is supplied from the sequence control device 21 to the numerical control device 20, and the start of the numerical control program for failure prediction shown in FIG. 4 is instructed.

As a result, the numerical control device 20 starts executing the numerical control program for failure prediction, and first reads M40 programmed in the first block N010. When the data of M40 is read, this data is output to the sequence control device 21 and is also supplied to the personal computer 30 via the sequence control device 21, and the personal computer 30 responds to the data as shown in FIG. Start execution of the monitor program. As a result, the fifth screen appears on the CRT screen of the personal computer 30.
The screen shown in the figure will be displayed.

At this time, the main shaft 11 is not rotating and the outputs of the AD converters 26a and 26b are zero, so the CRT
No bar graph is displayed on the screen, only the fixed part is displayed.

Subsequently, when S200 and M03 programmed in block N020 are read out by the numerical control device 20, a spindle rotation command is output from the sequence control device 21 to the rotation speed control device 22, and the rotation speed control device 22 The main shaft drive motor 16 is rotated at a speed corresponding to S200. Furthermore, when M45 of block N030 is subsequently read out and supplied to the sequence control device 21, the sequence control device 21 starts a timer whose time is set according to a certain monitoring time, and when this timer times out, The MFIN signal is supplied to the numerical control device 20. By supplying this MFIN, the numerical control device 20 reads M05 of block N040 and supplies it to the sequence control device 21. In response, the sequence control device 21 supplies a spindle stop command to the rotational speed control device 22 to stop the rotation of the spindle 11. With such a program, spindle 1
1 is to rotate at a speed corresponding to S200 until the timer provided in the sequence control device 21 times out. Note that the speed corresponding to S200 is the spindle speed when the vibration value and current value were measured during assembly.

When the spindle 11 is rotated in this manner, a predetermined current flows to the spindle drive motor 16, and vibrations are generated in the spindle head body 13. As a result, the outputs of the vibration detector 17 and the current detector 23 increase from zero, and the AD converters 26a and 26b output the vibration value v and the current value i during the spindle rotation.

During this time, the personal computer 30 is repeatedly executing steps (52) to (61) in _{FIG .} Value Sv, Si
The ratio of the size to that is calculated and displayed on the screen as shown in FIG.

This allows workers to see the CRT screen and
It is possible to know how much the magnitude of vibration during no-load rotation of the spindle 11 and the magnitude of the current supplied to the spindle drive motor 16 have increased compared to the normal state immediately after assembly. It is possible to easily and reliably discover that vibration has increased due to worn bearings or minute chips in gears, or that the load on the main shaft drive motor 16 has increased.

This makes it possible to predict major failures such as spindle seizure before they occur, and by predicting such failures and repairing them early, it is possible to prevent production from stopping due to a failure of the spindle device during machining. You can eliminate old problems.

In the above embodiment, the main shaft was rotated under no load by the numerical control program for failure prediction, but the main shaft was rotated by the program of the sequence control device 21 and the personal computer 30 monitors the main shaft. A command may also be supplied.

<Effects of the Invention> As described above, in the present invention, the normal state immediately after assembly is detected by a detector that detects at least one of the current value flowing through the spindle drive motor and the vibration value generated in the spindle device main body. The value at is detected in a no-load state and stored in the normal value storage means.
Therefore, the value stored in the normal value storage means is a value unique to each spindle device, including errors for each spindle device that occur during assembly. In this way, the same operation as when a normal value is detected is reproduced based on the command from the failure prediction means, so that the current detected value and the normal value can be compared under the same conditions. Taking into account errors during installation, and eliminating as much as possible load factors from elements other than the spindle device that occur during machining, the deterioration of the elements that make up the spindle device can be observed by measuring the spindle rotation while the spindle is rotating. This can be understood as an increase in the current value flowing through the motor or the vibration value generated in the spindle device body. Therefore, it is possible to early discover abnormalities that may lead to failures inside the spindle device, such as wear of the spindle bearings, and there is an advantage that failures of the spindle device can be predicted.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 shows the overall configuration of a spindle device equipped with a failure prediction device, and FIGS. 2 and 3 show the operation of the personal computer 30 in FIG. 1. flowchart,
FIG. 4 is a program sheet showing a numerical control program for failure prediction, and FIG. 5 is a diagram showing a display screen of the personal computer 30 in FIG. 11...Main shaft, 12...Bearing, 13...
Spindle head main body, 15... Gear mechanism, 17... Vibration detector, 20... Numerical control device, 21... Sequence control device, 22... Rotation speed control device, 23...
...Current detector, 26a, 26b...AD converter,
30...Personal computer.

Claims (1)

[Scope of Claims] 1. A detector that detects at least one of a vibration value generated by the rotation of the main shaft and a current value flowing through the main shaft drive motor, and a detector that detects at least one of the vibration value generated by the rotation of the main shaft and the current value flowing through the main shaft drive motor, and normal value storage means for storing the value detected by the detector when the
failure prediction instruction means for instructing execution of failure prediction; and upon receiving a command from the failure prediction instruction means, causing the main shaft to perform the same operation as when the normal value was stored by the normal value storage means. a rotation command means for driving the spindle drive motor in a no-load state, and a value detected by the detector while the spindle drive motor is rotating based on a command from the rotation command means; A comparison means is provided for comparing the magnitude of the value in the normal no-load state stored in the normal value storage means, and a failure of the spindle device is predicted based on the comparison result by the comparison means. Failure prediction device for spindle equipment. 2. The comparison means includes an AD converter that converts the output of the detector into a digital value, and compares the magnitude of the value converted to the digital value by the AD converter with the magnitude of the value under normal no-load conditions. A failure prediction device for a spindle device according to claim 1, characterized in that it is constituted by a computer capable of displaying the information on a screen.