JPS62136344A - Trouble prediction device for main spindle device - Google Patents

Abstract

PURPOSE:To make it possible to detect abnormality in a main spindle device which may lead to a trouble at an early stage and to predict the trouble by providing the main spindle device of a machine tool such as a machining center (MC) with a rotation command means, a vibration detector, and a display means. CONSTITUTION:After finishing a machine assembly, values of vibration and current are measured with a vibration detector 17 attached to the back of a main spindle head body 13 and with a current detector 23 arranged between a revolution control device 22 and a main spindle drive motor 16, and the measurements are stored via analog-digital converters 26a and 26b into a computer 30. After using the machine for a specified period of time, when a trouble predicting operation is commanded, a main spindle 11 rotates according to a monitor program to generate vibration in the main spindle body 13. The values of vibration and current at the time are similarly measured, compared with those in normal condition, and the result of comparison is displayed on a cathode-ray tube screen. This makes it possible to know easily the increase in the values of vibration and current compared with those in normal condition and to predict troubles.

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.

<Conventional technology> 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 driving the main shaft at a commanded speed. I'm trying to rotate it.

In such spindle devices, if the bearings wear out or gears become obscured 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 failures 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 prior art, the present invention is capable of predicting a failure of a spindle device, and includes a rotation command means for rotating a spindle of a machine tool under no load; A vibration detector for detecting vibrations generated by the rotation of the main shaft, and a display means for displaying the magnitude of the vibration detected by the vibration detector in a manner that can be compared with the magnitude of vibration during normal no-load conditions. It is characterized by:

<Operation> The rotation command means is activated at regular intervals to rotate the main shaft under no load. Vibration generated when the main shaft is rotating based on the command from the rotation command means is detected by the vibration detector and displayed by the display means. The display means displays the magnitude of the detected vibration so that it can be compared with the magnitude of vibration under normal no-load conditions.

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 supported by a spindle head main body 13 via a pair of bearings 12 and 12. The main shaft 11 is connected to an output shaft of a main shaft driving motor 16 via a gear mechanism 15 that can change the reduction ratio. Further, a vibration detector 17 for detecting vibrations generated in the spindle head body 13 is attached to the back surface of the spindle head body 13.

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.

Further, a rotation speed control device 22 that controls the rotation speed of the spindle drive motor 16 is connected to the numerical control device 20, and the S code included in the numerical control program is read by the numerical control device 20. Information on this S code is output to the rotation speed control device 22, and after that, when a spindle rotation command is supplied from the sequence control device 21, the spindle drive motor 16 is rotated at the speed instructed by the S code. It has become. Furthermore, the rotational speed control device 22
The main shaft drive motor 1 is connected between the main shaft drive motor 16 and the main shaft drive motor 16.
A current detector 23 is provided to detect the magnitude of the current flowing through the terminal 6.

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 output of the current detector 23 is supplied via amplifiers 25a, 25b and AD converters 26a, 26b. 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.

When the command "VS" for inputting a vibration setting value is keyed in using the keyboard 30a of the personal computer 30, the value input following "VS" is stored as the vibration setting value Sv by the process shown in FIG. 40),
When the command "IS" for inputting the current setting value is keyed in, the value input following "rs" is stored as the setting current value Si by the process shown in FIG. 2(b) (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. The process of displaying only fixed parts such as frames and titles on the monitor screen shown in the figure (5)
0), the maximum value Dvo in the buffer, and 1) io are cleared to zero (51). Thereafter, the monitor routine of steps (52) to (61) is repeatedly executed until the code MO2 indicating the end of the program is output from the numerical control device 20 via the sequence control device 21.

In this monitor routine, AD conversion 526a.

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 Dvo and Dio (53), (56) , if large, v,
Cent i as the maximum value Dvo, Dio (55),
(57). Then, the maximum values Dvo and Dio are divided by the set values Sv and 3i, respectively, to obtain the maximum value pvo for the set values Sv and Si.

Calculate the relative sizes DDv and DDi of Dio (5
8), and after this, in order to display a bar graph according to the size of DDv and DDi on the CRT screen, the length of the bar graph on the 11 screen is calculated (60), and this calculated length is Processing is performed to display the bar graphs 31a and 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 an unloaded state, and the AD converters 26a, 2
“VS” is the output value of 6b.

Input using the “IS” command. As a result, the personal computer 30 sets the magnitude of the vibration in the no-load state and the magnitude of the current value to the set value Sv by the processing shown in FIGS. 2A and 2B.

It is registered as Si in a non-volatile storage area.

Thereafter, after the machine is installed at the customer's factory, the failure predictive operation button 29a on the operation panel 29 is pressed periodically 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 failure prediction numerical control program shown in FIG. 4 is instructed.

As a result, the numerical control device 20 starts executing the numerical control program for fault detection, and first, the first block N0
Read M2O programmed in IO. M2O
When the data is read out, this data is output to the sequence control device 21 and also supplied to the personal computer 30 via the sequence control device 21.
In response to this, the personal computer 30 starts executing the monitor program shown in FIG. This results in
A screen shown in FIG. 5 is displayed on the CRT screen of the personal computer 30.

At this time, the main shaft 11 is not rotating, and the AD converter 26a
, 26b is zero, so no bar graph is displayed on the CRT screen, and only the fixed portion is displayed.

This is followed by 5200. programmed in block NO2O. When the MOS is read 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 spindle drive motor 16 is rotated at a speed corresponding to 200. 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 this timer When time amplifiers, M
The FIN signal is supplied to the numerical control device 20. This midfielder
By supplying IN, the numerical control device 20 switches to block N04.
The MO5 of 0 is read out and supplied to the sequence control device 21. In response, the sequence control device 21 supplies a spindle stop command to the rotation speed control device 22, and the spindle 11
stop the rotation. With such a program, the main shaft 11 is rotated at a speed corresponding to 5200 until the timer provided in the sequence control device 21 times out.

Note that the speed corresponding to 5200 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 vibration detector 17,
The output of the current detector 23 increases from zero, and the output of the AD converter 26 increases.
Vibration value V and current value i during spindle rotation from a and 26b
is output.

During this time, the personal computer 30 repeatedly executes the processes of steps (52) to (61) in FIG. , Si is calculated and displayed on the screen as shown in FIG.

This allows the operator to check the spindle 1 by looking at the CRT screen.
It is possible to know how much the magnitude of vibration during no-load rotation of the main shaft bearing 1 and the magnitude of the current supplied to the main shaft drive motor 16 have increased compared to the normal state immediately after assembly. It is possible to easily and reliably discover that the vibration has increased due to wear of the gears, slight chipping of the gears, etc., 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 if such failures are predicted and repaired early, the spindle device will fail during machining and production will stop. It is possible to eliminate such 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 is rotated by the program of the sequence control device 21 and a monitor command is supplied to the personal computer 30. You can do it like this.

<Effects of the Invention> As described above, in the present invention, the main shaft is rotated under no load, the magnitude of vibration generated during the rotation of the main shaft is detected, and the magnitude of this vibration is measured immediately after assembly. Since the display is made so that it can be compared with the magnitude of vibration under normal conditions, it is possible to easily understand how much the vibration has increased during rotation of the main shaft. Therefore, abnormalities that lead to failure of the spindle device, such as wear of the spindle bearing, can be discovered at an early stage, and there is an advantage that failure 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. 4 is a flowchart, FIG. 4 is a program sheet showing a numerical control program for failure prediction, and FIG. 5 is a diagram showing the display screen of the personal computer 30 in FIG. DESCRIPTION OF SYMBOLS 11... Main shaft, 12... Bearing, 13... Spindle head body, Engineering 5... Gear mechanism, 17... Vibration detector, 20... Numerical controller, 21... Sequence control Apparatus, 22... Rotation speed control device, 23... Current detector, 26a, 26b... ADimW, 30... Personal computer.

Claims (2)

[Claims] (1) A rotation command means for rotating the main spindle of a machine tool under no load, a vibration detector for detecting vibrations generated by the rotation of the main spindle, and a vibration detector for detecting vibrations detected by the vibration detector. 1. A failure prediction device for a spindle device, comprising display means for displaying the magnitude of vibration under load in a manner that can be compared with the magnitude of vibration. (2) The display means includes an AD converter that converts the output of the vibration detector into a digital value, and the magnitude of the vibration converted to the digital value by the AD converter as the magnitude of the vibration 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 that displays images on a screen in a manner that can be compared.