JPS5914130Y2 - cutting equipment - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a cutting device that can effectively detect abnormal machining conditions in, for example, an automatic lathe and prevent damage to the workpiece or the device.

In cutting equipment such as automatic lathes, if the tool is damaged or machining chips get stuck between the workpiece and the guide bushing, the guide bushing or check may seize, or the automatic There are problems such as damage to the size of the tool to be fed and, ultimately, damage to the device.

For this reason, processing workers have traditionally been able to monitor the processing status,
We try to prevent the above abnormal situations from occurring by paying attention to abnormal sounds.

However, in this type of monitoring, the abnormal situation is often already well advanced by the time an abnormality is detected, which results in system failure of the device, making it impossible to save labor or improve productivity.

Furthermore, in recent years, the load current of the motor that drives the spindle mechanism has been monitored to detect abnormalities.

However, in general, the difference between the load current value during normal machining of the motor and the load current value when the guide bushing or chuck is seized is not very large, so it is very difficult to set a comparison current value to distinguish between abnormality and normality. It was difficult and prone to false positives.

The present invention was developed in consideration of these circumstances, and its purpose is to stably detect abnormalities such as tool damage and checking, and guide bushing seizures at an early stage, and to avoid such abnormalities. We have realized cutting equipment that can effectively perform cutting operations to save labor and improve productivity.
It is about providing.

Hereinafter, one embodiment of the device of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic diagram of an automatic lathe apparatus, in which a headstock 2 and a tool stand 3 are installed on a base 1.

The headstock 2 includes a spindle mechanism therein, and is equipped with a chuck 4 for fixing a workpiece to the spindle.

Further, a guide bush 5 is disposed on the tool stand 3 coaxially with the chuck 4.

The workpiece 6 to be subjected to cutting passes from the headstock 2 through the chuck 4 and the guide bush 5, and is fixed to the main shaft by the chuck 4 so that it can be rotated.

Further, a processing tool 7 is attached to the tool stand 3, which is controlled to move up and down in a direction perpendicular to the direction of the rotational axis of the workpiece 6, and which cuts the workpiece 6 by coming into contact with the workpiece 6. .

Incidentally, the feed control of the processing tool 7 is performed by an unillustrated control device.

Further, the feed of the workpiece 6 in the direction of the arrow in the figure is similarly performed by a feed mechanism and a feed control device (not shown).

Now, in such a lathe, a rotation detector 9 consisting of a rechargeable rotary encoder or the like is placed on the feed table 8 which is linked to the feed mechanism that controls the feed of the workpiece 6.
Fixed.

The rotation detector 9 has an end 9a of its rotation detection shaft coaxially pressed against the end of the workpiece 6 by being biased by a spring 10.

Therefore, the end 9a of the shaft contacts the end of the workpiece 6 without slipping due to the pressing force of the spring 10, and rotates integrally with the workpiece 6.

The rotation detector 9 detects the workpiece 6 from the rotation of the rotation detection shaft.
For example, the number of rotations (rotational speed) is detected.

The rotational speed of the workpiece 6 detected in this manner is subjected to the following signal processing, and is used for early detection of abnormalities in cutting processing.

That is, as shown in FIG. 2, the rotation speed information of the workpiece 6 obtained by the rotation detector 9 is input to the comparator circuit 11 and compared with the reference rotation speed set in the rotation speed setting device 12. has been determined.

The comparison circuit 11 and the rotation speed setting device 12 constitute a rotation abnormality detection circuit 20.

The comparison reference rotation speed corresponds to the rotation speed of the workpiece 6 when cutting is normally performed in this apparatus.

Therefore, when the rotation speed detected by the rotation detector 9 is smaller than the set rotation speed, the comparison circuit 11 determines that an abnormality has occurred in the cutting process and outputs an abnormality detection signal.

The abnormality detection signal thus obtained by the rotational abnormality detection circuit 20 is selectively outputted via a gate circuit 13, which will be described later.

On the other hand, a control signal for determining whether or not to drive the spindle mechanism 19 in the control mechanism 14, that is, a rotation control signal for the electric motor, is input to the gate circuit 15 outside the spindle mechanism 19, and is also input to the delay circuit 16.

This delay circuit 16 delays the input signal (rotation control signal) by a delay time determined by a delay time setting device 17 and outputs the delayed signal.

Note that the circuits 13, 15 to 17 constitute an abnormality detection signal extraction circuit 30.

The gate circuit 15 controls the passage of the rotation control signal mentioned above based on the output of the delay circuit 16.

That is, the rotation control signal outputs, for example, a HIGH level signal when rotating the electric motor, and a LOW level signal when stopping the electric motor.

Therefore, under the control of the delay circuit 16, the gate circuit 15 outputs the rotation control signal after a predetermined delay time has elapsed since inputting the HIGH level rotation control signal.

When the rotation control signal becomes LOW level,
The outputs of data 1 to circuit 16 are immediately stopped.

However, if the delay time is defined as the period from when a rotation control signal is given to the motor to start the motor and reach steady rotation, the gate circuit 15 outputs a signal only when the motor is in steady operation. Become.

The output signal of this gate circuit 15 is outputted as a gate opening signal of the gate circuit 13.

Therefore, the gate circuit 13 extracts and outputs the abnormality detection signal described above only during steady operation of the motor.

The abnormality detection signal obtained through this gate circuit 13 is input to an alarm circuit 18, and the circuit 18 issues an alarm for abnormality detection.

At the same time, the output of the gate circuit 13 is transmitted to the control mechanism 14.
The occurrence of the abnormality has been recognized.

Further, the control mechanism 14 stops the supply of driving power to the electric motor of the spindle mechanism 19, brakes the rotation of the spindle to stop the rotation, and also controls the tool feeding mechanism to move the tool 7. Feeding is stopped.

However, when an abnormality is detected, processing is immediately stopped.

According to the apparatus configured in this way, the workpiece 6 may be damaged due to an increase in the machining load due to, for example, the tool 7 being damaged or machining chips becoming stuck between the workpiece 6 and the guide bush 5. When rotation becomes difficult and the rotation speed decreases,
This can be quickly detected by the comparison circuit 11.

Moreover, since this detection is not performed during the initial period when the electric motor is started, there is no possibility of erroneously detecting an abnormality during low-speed rotation during a transient change in rotational speed during the same period.

Furthermore, since abnormality detection is performed by directly detecting the rotational speed of the workpiece 6, abnormality detection can be reliably performed before the load current of the motor changes.

Moreover, detection can be performed without being adversely affected by slippage between the workpiece 6 and the chuck 4.

Therefore, abnormal conditions in machining can be detected at an early stage, and appropriate measures for the abnormalities can be taken promptly.

Therefore, seizure of the guide bush 5 and chuck 4 can be prevented, and system failure of the apparatus can also be prevented.

Further, it is possible to prevent a chain reaction of damage from the abnormal tool 7 or other parts to other normal parts.

Therefore, abnormal parts and the like can be replaced easily and quickly in a short period of time, thereby improving productivity and saving labor.

Furthermore, since the rotation detector 9 is used to control the feed of the workpiece 6 in the same manner as the feed of the workpiece 6, the apparatus can be handled in the same manner as before without impairing workability, thereby causing no inconvenience.

Therefore, cutting can be performed extremely safely and efficiently.

Note that the present invention is not limited to the above embodiments.

For example, the rotation detector may be installed coaxially with the workpiece 6 in the region of the machined part, or it may also be placed in contact with the side circumference of the workpiece to serve as a rotation steady rest. good.

Also, for abnormality determination, the rotation speed during steady rotation is memorized.
The determination may be made based on the magnitude of the difference between the stored value and the number of revolutions during machining, or the determination may be made based on the ratio of the above values.

In short, the present invention can be implemented with various modifications without departing from the gist thereof.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which Fig. 1 is a schematic diagram of an automatic lathe device, and Fig. 2 is a configuration diagram of a signal processing circuit. 2... Headstock, 3... Tool stand, 4... Chuck,
5... Guide bush, 6... Work material, 7... Tool, 9... Rotation detector, 10... Spring, 11...
Comparison circuit, 13.15...Gate circuit, 14...Control mechanism, 16...Delay circuit, 18...Alarm circuit, 1
9... Main shaft mechanism, 20... Rotation abnormality detection circuit, 30
...Anomaly detection signal extraction circuit.

Claims (1)

[Scope of utility model registration request] A spindle mechanism that holds and rotates the workpiece, a control mechanism that outputs a rotation control signal to the spindle mechanism to rotate the workpiece, and a liquid-distributing cutting material held by the spindle mechanism. A rotation detector is provided to detect the rotation speed of the workpiece, and a signal indicating the rotation speed output from the rotation detector is input, and this signal and a preset reference rotation speed are input. a rotational abnormality detection circuit that outputs an abnormality detection signal based on the delay time, and a rotational abnormality detection circuit that has a delay time set in advance and inputs the abnormality detection signal and the rotation control signal; and an abnormality detection signal extraction circuit that inputs only the abnormality detection signal as described above into the control mechanism, which is output after an initial period of ゛ has elapsed from the start of the spindle mechanism until it reaches steady operation. Cutting equipment.