JPH0511821A - Numerical controller equipped with automatic tool replacement device - Google Patents

Abstract

PURPOSE:To perform safe tool replacement while avoiding the interference between a tool, and a pot and a main shaft and to shorten the time of the tool replacement by controlling simultaneous operation while detecting the current positions of two servo motors which drive the numerical control automatic tool replacement device. CONSTITUTION:A simultaneous operation start position detecting means 8 detects a swivel start position where the interference between the tool, and pot and main shaft can be avoided even if a tool replacement arm begins to swivel halfway in tool extraction and an insertion start position where the interference between the tool, and pot and main shaft can be avoided even if the tool begins to be inserted during the swivel of the tool replacement arm. Thus, the accurate simultaneous operation start positions are detected by detecting the current positions of the swivel shaft and insertion/extraction shaft of the tool replacement arm, so simultaneous operation can be performed while operation in the inserting/extracting direction is corrected by the movement in the inserting/extracting direction by the swivel operation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to numerical control (hereinafter referred to as NC
The present invention relates to an NC device equipped with an automatic tool changer for machine tools (hereinafter referred to as ATC).

[0002]

2. Description of the Related Art FIG. 4 is a numerical control ATC in which a turning and a slipping operation of a tool changing arm are driven by servo motors.
It is a skeleton diagram showing an example (hereinafter referred to as NC-ATC). Since the ball screw 11 and the spline 12 are integrated and the tool exchange arm 13 is fixed to one end of the ball screw 11, the rotation of the ball screw 11 turns the tool exchange arm 13. Also, the ball screw nut part 1
Since 4 can be rotated only and is fixed in the tool removing direction, the ball screw 11 itself moves in the tool removing direction when the ball screw nut portion 14 rotates. Further, the tool changing arm turning servomotor 15 drives the spline 12 via the gear and the speed reducer 7. The tool changing arm removal servomotor 16 is provided with a ball screw nut portion 14 via a gear.
To drive. Like the ball screw nut portion 14, the tool exchange arm removal servomotor 16 and the gear are fixed in the tool removal direction.

In order to rotate the tool changing arm 13 as described above, it is necessary to rotate the ball screw 11 as well. Therefore, when only the tool changing arm turning motor 15 is driven in a state where the tool changing arm removing servomotor 16 is stopped, the tool changing arm 13 turns while the tool changing arm 13 is turning because the ball screw nut portion 14 is stopped. It will move in the direction. Therefore, the tool change arm moves in the positive direction a
[Deg] When moved, b in the positive direction of the tool removal direction
Assuming that the tool changing arm 13 is moved by [mm], when the tool changing arm 13 is rotated by f (t) [deg], it is − (b
The mechanical position of the tool changing arm 13 is kept constant by correcting only / a) × f (t) [mm].

FIG. 5 is a block diagram showing an example of an NC device having an NC-ATC. Tool change command input means 21
From the tool change sequence control means 22 to the tool change command S
When TC is sent out, the tool change arm swing command SAR and the tool change arm removal command SA at constant timing.
P is sent to the tool exchange arm turning axis control means 23 and the tool exchange arm removal axis control means 25. A function is generated when the tool change arm swing command SAR is sent to the tool change arm swing axis control means 23, and the swing command f (t) is used as the swing command f (t) and the tool change arm slippage amount correction means 26. Sent to. In the tool change arm difference amount correction means 26, the movement amount of the tool change arm in the difference direction due to the turning operation is only − (b / a) × f (t) so as to keep the mechanical position of the tool change arm constant. The command g '(t) for correction is sent to the servomotor drive device 27 for slipping. On the other hand, when the tool exchange arm removal shaft control means 25 sends the tool exchange arm removal command SAP, a function is generated and the removal command g (t) is sent to the removal servo motor drive device 27. .

FIGS. 6 (a) and 6 (b) are views showing the relationship between the moving speed and time of the turning and slipping movements of the tool changing arm, and the servo motor is driven by a command from the servo motor drive unit. , The tool exchange arm swings from the retracted position and grasps the tool to loosen the tool. After the completion of the tool loosening, the tool exchanging arm takes out the tool, and after the completion of the taking out, the tool exchanging arm rotates 180 degrees. After the turning is completed, the tool exchange arm inserts the tool into the pot and the main spindle to tighten the tool, and after the tool fastening is completed, the tool exchange arm returns to the retracted position. FIG. 7C is a diagram showing the relationship between the moving speed and time of the correction operation for the movement in the tool removal direction due to the turning of the tool changing arm, and the respective timings are equal to the turning operation timing. Further, (d) shown in the same figure is a diagram showing the relationship between the actual moving speed of the removal servomotor and time.

[0006]

The above-mentioned conventional NC-
In order to shorten the tool exchange time in the NC device equipped with the ATC, the operating speed of the tool exchange arm may be increased. However, when the speed cannot be increased due to the mechanical strength or when there is a limit on the performance of the motor, it is necessary to shorten the tool replacement time by simultaneously operating the swivel and the removal of the tool replacement arm. However, in the NC-ATC, the tool changing arm is driven by two servo motors for turning and for sliding. These two servomotors are independently controlled, and there is a problem that it is difficult to operate them simultaneously while avoiding interference between the tool, the pot and the spindle. The present invention has been made under the circumstances as described above, and an object of the present invention is to simultaneously provide two servo motors for turning and for removing a tool changing arm while avoiding interference between the tool and the pot and the spindle. An object is to provide an NC device equipped with an NC-ATC that can be operated.

[0007]

The present invention provides an NC equipped with an NC-ATC for exchanging tools between a spindle of an NC machine tool and a pot of a tool magazine device by a tool exchanging arm.
The above object of the present invention relates to a device, a swivel start position capable of avoiding interference between the tool, the pot and the spindle even if the swivel of the tool exchanging arm is started in the middle of removing the tool, and the tool. Even if the insertion of the tool is started during the swing of the exchange arm, the insertion start position capable of avoiding the interference between the tool and the pot and the spindle is provided with detection means, and the removal of the tool exchange arm is performed. This is achieved by making the differential and swivel motions partly simultaneous.

[0008]

In the present invention, since the accurate simultaneous operation start position is detected by detecting the current position of the tool changing arm on the turning axis and the pulling shaft, the movement amount in the pulling direction due to the turning motion is detected. The simultaneous operation can be performed while correcting the operation in the slip direction.

[0009]

1 is a block diagram showing an example of an NC apparatus equipped with an NC-ATC according to the present invention, corresponding to FIG. When the tool exchange command STC is sent from the tool exchange command input means 1 to the tool exchange sequence control means 2, the tool gripping command STH and the tool removal command STP are transmitted as the tool exchange arm pivot axis control means 3 and the tool exchange arm removal. Axis control means 5
Sent to. When the tool gripping command STH is sent to the tool change arm swing axis control means 3, a function is generated,
The turning command f (t) is sent to the turning servo motor drive device 4 and the tool change arm difference amount correction means 6. In the tool exchange arm slippage amount correction means 6, the movement amount in the slippage direction due to the turning motion of the tool exchange arm is-(b / a) × f (t).
A command g '(t) for correcting only this is sent to the servomotor drive 7 for slipping. This causes the tool change arm to pivot from the retracted position to grab the tool.

On the other hand, when the tool difference command STP is sent to the tool change arm difference shaft control means 5, a function is generated and the difference command g (t) is sent to the tool change arm difference amount correction means 6. To be done. Since the simultaneous operation is not performed at this time, the output g'of the tool change arm removal amount correction means 6
(T) is g (t) as it is, and the servomotor drive device 7 for slipping
And the tool change arm is driven in the pull-out direction.
The simultaneous operation start position detection means 8 has detected the positions of the tool changing arm on the turning axis and the removal axis, and when the removal axis position reaches the turning start position, the tool change sequence control means 2 is requested to start turning. The command SSR is sent. When the tool exchange arm 180-degree turning command SAR is sent from the tool changing sequence control means 2 to the tool changing arm turning axis control means 3, a function is generated and the turning command f (t) is given to the turning servo motor drive device 4. It is sent out and the tool change arm is driven in the turning direction. In parallel with this, the turning command f (t) is also sent to the tool change arm difference amount correction means 6, and the difference command g (t) from the tool change arm difference axis control means 5 is g ″ (t). = G (t)-(b / a) * f (t) and sent to the servomotor drive device 7 for slippage, whereby the two servomotors keep the mechanical position of the tool change arm constant. Drive to keep.

When the simultaneous operation start position detecting means 8 detects that the turning axis position is at the insertion start position after the tool removal, the insertion start request command SSP is sent to the tool exchange sequence control means 2. It When the tool exchange arm insertion command SAP is sent from the tool exchange sequence control means 2 to the tool exchange arm removal axis control means 5, a function is generated,
The removal command g (t) is sent to the tool change arm removal amount correction means 6. In the tool change arm removal amount correction means 6, the removal command g (t) is g ″ (t) = g (t) − (b / a) ×
It is corrected to f (t) and sent to the servomotor drive device 7 for slipping. As a result, the inserting operation is performed while turning the tool changing arm 180 degrees. After the insertion of the tool is completed, the tool exchanging arm is retracted according to the same command flow as when gripping the tool.

3 (a) and 3 (b) are diagrams showing the relationship between the moving speed and the time of the turning and slipping movements of the tool changing arm, and the servo motor is driven by a command from the servo motor driving unit. , The tool exchange arm swings from the retracted position and grasps the tool to loosen the tool. After the tool loosening is completed, the tool changing arm pulls out the tool, and when the removal shaft position reaches the turning start position, the tool changing arm starts turning 180 degrees and performs the simultaneous operation. When the turning axis position reaches the insertion start position after completion of extraction, tool insertion is started and simultaneous operation is started. Then, the tool is inserted into the pot and the spindle to tighten the tool, and after the tool is tightened, the tool exchanging arm returns to the retracted position. FIG. 7C is a diagram showing the relationship between the moving speed and time of the correction operation for the movement in the tool removal direction due to the turning of the tool changing arm, and each timing is equal to the timing of the turning operation. Further, (d) shown in the same figure is a diagram showing the relationship between the actual moving speed of the removal servomotor and time.

FIG. 2 shows an NC equipped with the NC-ATC of the present invention.
It is a block diagram which shows another example of an apparatus corresponding to FIG. 1, and the same code | symbol is attached | subjected to the same component and description is abbreviate | omitted. From the simultaneous operation start position detection means 8 to the simultaneous operation start determination means 9
Turn start request command SSR and slip start request command SSP
Is sent, the movement speeds of the swivel axis and the removal axis of the tool changing arm are detected by the simultaneous operation start determining means 9. Then, at the turning start position, the time it takes for the tool to come out of the pot and the spindle, and the time until the tool goes through the pot and the hole at the spindle end by the turning movement of the tool changing arm from the center of the hole at the pot and spindle end. Are compared and it is confirmed that the tool does not interfere with the pot and the spindle, and then a turning start request command SSR is sent to the tool change sequence control means 2 to start the simultaneous operation. At the insertion start position, the time it takes for the tool to reach the center of the pot and the hole at the spindle end by the turning motion of the tool changing arm is compared with the time it takes for the tool to start the insertion motion and reach the pot and the spindle end. ,
After confirming that the tool does not interfere with the pot and the spindle, the insertion start request command S is sent to the tool change sequence control means 2.
SP is sent and simultaneous operation is started.

[0014]

As described above, according to the NC device having the NC-ATC of the present invention, the simultaneous operation is controlled while detecting the current positions of the two servo motors for driving the NC-ATC. It is possible to perform safe tool exchange while avoiding interference with the pot and the spindle, and shorten the tool exchange time. Further, by detecting the speeds of the two servo motors, it is possible to deal with a delay in the movement of the tool exchanging arm due to a change in the rising moment when exchanging the heavy tool.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of an NC device including an NC-ATC of the present invention.

FIG. 2 is a block diagram showing another example of an NC device including the NC-ATC of the present invention.

FIG. 3 is a diagram showing the relationship between the moving speeds of the swivel axis and the slide shaft of the tool changing arm of the NC-ATC and time in the device of the present invention.

FIG. 4 is a skeleton diagram showing an example of NC-ATC.

FIG. 5 is a block diagram showing an example of an NC device including a conventional NC-ATC.

FIG. 6 is a diagram showing the relationship between the moving speeds of the swivel axis and the slip-off shaft of the tool changing arm of the NC-ATC and the time in the conventional device.

[Explanation of symbols]

8 Simultaneous operation start position detection means 9 Simultaneous operation start determination means

Claims (2)

[Claims] 1. A numerical control device equipped with an automatic tool changing device for exchanging tools between a spindle of a numerically controlled machine tool and a pot of a tool magazine device by means of a tool changing arm, wherein the tool changing arm is A swivel start position capable of avoiding interference between the tool and the pot and the spindle even when the swivel is started, and the tool, the pot and the spindle even if the insertion of the tool is started during the swiveling of the tool exchanging arm. An automatic tool changer, comprising a detection means for detecting an insertion start position capable of avoiding interference with the tool changer arm, and a part of the tool changer arm's pulling and turning operations are simultaneously performed. Numerical control device equipped with. 2. The speed of the tool changing arm in the tool withdrawing direction is detected at the turning start position, it is determined from the speed of the tool withdrawing direction that the tool does not interfere with the pot and the spindle, and the insertion start is started. The automatic tool according to claim 1, further comprising a determination unit that detects a speed of the tool changing arm in a tool turning direction at a position and determines from the speed of the tool turning direction that the tool does not interfere with the pot and the spindle. Numerical control device with switching device.