JP3097182B2 - Screw processing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thread processing device represented by a tapping machine.

[0002]

2. Description of the Related Art Conventionally, a tapping operation in a threading device to which an NC device is applied is controlled only by generating a feed command and a rotation command in the NC device in accordance with a pitch of a screw to be processed. The motor and the spindle rotation motor were controlled as independent servo systems. The deviation between the feed amount and the rotation amount that occurs when the rotation motor is reversed is absorbed by the mechanical expansion and contraction of the tapper between the tap tool and the main shaft. For this reason, there has been a problem that the screw processing speed is limited by the performance of the tapper, and the accuracy of the screw is reduced due to the force due to the expansion and contraction of the tapper.

[0003] Therefore, there has been proposed a device for controlling the feed motor and the rotary motor in synchronization with each other, such as a device for driving the feed motor in accordance with a value obtained by adding the rotational speed and acceleration of the rotary motor (Japanese Patent Laid-Open No. 64-58425). ing. Since these devices have high synchronization accuracy between the feed and the rotation, screw processing can be performed without using a tapper in most cases.

[0004]

However, in recent years,
Shortening of the processing time is further demanded, and high-speed processing close to the limit of the tap tool may be performed even in screw processing. In such a case, for example, in a conventional device that drives the feed motor in accordance with a value obtained by adding the rotational deviation of the rotary motor and the acceleration of the rotational deviation, if the acceleration changes in the rotation of the rotary shaft, the feed motor is switched to the rotary motor. On the other hand, there is a problem in that a following delay is caused, and there is a limit in improving the accuracy of thread machining. In particular, processing with shallow threading depth,
Or, if the speed of the processing performed while the tool is stepped with a small step width is increased, the processing in the state where the change of the acceleration of the feed and the rotation is sharp increases, and when the motor is driven by servo control etc., the error due to the following delay is reduced. This is a big problem.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has improved the followability of a feed movement with respect to a rotary shaft, so that even at the time of high-speed tapping close to the limit of a tapping tool, accuracy can be improved. It is an object of the present invention to provide a screw processing device capable of performing high-speed screw processing.

[0006]

In order to achieve this object, a threading device according to the present invention is a threading device for performing a tapping operation by synchronously operating a rotary motor for rotating a main shaft and a feed motor for driving a feed. In the apparatus, a rotational position detecting means for detecting a rotational position of the main shaft, a rotational deviation calculating means for calculating a rotational deviation between the rotational position of the main shaft detected by the rotational position detecting means and a rotation command value, and according to the rotational deviation a rotation driving means for driving the rotary motor, the rotary
From the rotation deviation value calculated by the deviation calculation means,
A rotational acceleration calculating means for calculating a speed;
Rotation jerk from the value of the rotation deviation calculated by the calculation means
Rotation jerk calculation means for calculating
Means for calculating the rotational deviation calculated by the
And the rotational acceleration calculated by the calculating means.
From the rotational jerk calculated by the speed calculating means,
A feed command value calculating means for calculating a feed command value corresponding based on the thread pitch, detection by the rotational position detecting means
Equivalent based on the thread pitch from the issued spindle rotation position
Feed correction value calculating means for calculating a feed correction value
Feed position detecting means for detecting the feed position of the
The positive value and the machine detected by the feed position detecting means
Feed deviation calculating means for calculating a feed deviation from the feed position;
Correction means for correcting the feed command value based on the feed deviation
And the feed command value corrected by the correction means.
Feed driving means for driving a feed motor .

[0007]

According to the screw machining apparatus of the present invention having the above-described structure, the rotation motor calculates the rotation deviation between the rotation position of the main shaft detected by the rotation position detection means and the rotation command value by the rotation deviation calculation means. Are driven by the rotation driving means in accordance with the rotation deviation.

On the other hand, the feed position of the machine is based on the feed command value.
The feed command value is usually controlled by the spindle
Can be calculated based on the rotation speed and the screw pitch. However
When the spindle speed increases or decreases (
That is, if the acceleration changes), the actual
Command based on the spindle rotation position and screw pitch
Even if the value is calculated, the rotation motor is
Because feedback control is performed in the system,
The feed position is likely to cause a delay in following the spindle rotation.
You. Therefore, the feed command value calculating means calculates the rotational deviation.
The rotational deviation calculated by the calculating means and the rotational deviation
The rotation calculated by the rotational acceleration calculating means based on
Rolling acceleration and the rotational jerk based on the rotational deviation.
Considering the rotational jerk calculated by the calculating means,
At some point, the rotational speed, including the
Calculate the feed finger based on the rotation speed and the screw pitch.
Calculate the quotation. As a result, based on this feed command value,
The feed position of a machine controlled by
Will be moved to an anticipated position.
Follow-up delay is suppressed.

In addition, the feed correction value calculation means uses
Calculates feed correction value based on screw pitch from rotation position
Detected by the feed correction value and feed position detecting means.
The feed deviation from the feed position of the machine
Calculated by the correction means and the feed drive means.
The feed command value calculated by the feed command value calculating means
Is corrected based on the actual feed position, and the feed motor system
Since feedback control is also performed, the feed command value and
The delay in following the actual machine feed position can be suppressed.
You.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a thread working device according to the present invention.

The machine main body 1 of the screw processing apparatus forms a vertical tapping machine, and a column 3 is provided upright on a base 2.
A spindle head 5 is vertically slidably supported via a slider 4, and the spindle head 5 is engaged with a ball screw 6. The ball screw 6 is connected to a feed motor 7 composed of an AC servomotor and is rotated and moved up and down the spindle head 5. The feed motor 7 is provided with a tach generator 8 for detecting a rotation speed and a pulse generator 9 for detecting a rotation position. The pulse generator 9 is used to move the machine
And a feed position detecting means for detecting the position.

A spindle 10 is rotatably supported by the spindle head 5 and is driven to rotate by a rotation motor 11. The rotary motor 11 is composed of an AC servomotor, and is provided with a tacho generator 12 for detecting a rotational speed and a pulse generator 13 for detecting a rotational position. Pulse generator 1
Reference numeral 3 denotes a rotational position detecting means for detecting the rotational position of the main shaft 10.

A tapping tool 14 is directly attached to the lower end of the main shaft 10 without passing through a tapper, and screws a workpiece 16 having a prepared hole 15.

A control circuit of a rotation system (referred to as an R axis) for controlling the rotation of the main shaft 10 will be described.

A rotation command value R is calculated by a calculator 22 based on the data input from the input device 21 and output to the rotation deviation counter 23 as a pulse train corresponding to the rotation speed. A pulse corresponding to the rotation angle of the rotation motor 11 is input from the pulse generator 13 to the rotation deviation counter 23 as a position feedback pulse. In the rotation deviation counter 23, a deviation E (R) = R−r between the rotation command value R and the rotation position r of the main shaft detected by the pulse generator 13.
And outputs the rotation deviation E (R) to the rotation servo amplifier 24 as a speed command. A signal v (r) corresponding to the actual speed from the tacho generator 12 is input to the rotary servo amplifier 24 as a speed feedback signal, and drives the rotary motor 11 in a speed loop system. The control circuit for the rotation system (R-axis) has the same circuit configuration as that used for normal rotation control.

Next, a feed system (Z) for moving the spindle head 5 up and down.
The control circuit will be described. In the feed system, the feed command value Z is not directly given from the input device 21, but is calculated and controlled from the rotation deviation E (R).

The rotational deviation E from the rotational deviation counter 23
(R) is input to the acceleration calculator 25 and the jerk calculator 26. The acceleration calculator 25 calculates the rotation acceleration A (E) = d / dt × E (R) from the rotation deviation E (R), and outputs the acceleration A (E) to the adder 27. The jerk calculator 26 calculates the jerk B of the rotation from the rotation deviation E (R).
(E) = d2 / dt2 × E (R) is calculated, and the jerk B (E) is output to the adder 27. The rotation deviation E (R) from the rotation deviation counter 23 is input to the input of the adder 27.

The adder 27 adds the rotational deviation E (R), the acceleration A (E) of the rotational deviation E (R), and the jerk B (E) of the rotational deviation E (R), and calculates a feed command value calculator. 28. Since the rotation deviation E (R) is a value corresponding to the actual rotation speed v (r), the output of the adder 27 is the sum of the rotation speed, acceleration, and jerk (E (R) + d /
dt × E (R) + d2 / dt2 × E (R)). The feed command value calculator 28 outputs the output of the adder 27 to P / based on the thread processing pitch P and the lead L of the ball screw 6 which are input from the input device 21 and given through the calculator 22 in advance.
L times feed command value Z = P / L × (E (R) + d / dt ×
E (R) + d2 / dt2 × E (R)) is calculated. Rotation
Acceleration calculator 25 as speed calculation means , rotational jerk
The jerk calculator 26, the adder 27 and the feed command value calculator 28 as the calculating means constitute the feed command value calculating means.

The feed command value Z output from the feed command value calculator 28 is a value corresponding to the sum of the rotational speed, the acceleration and the jerk. Value. Then, the feed command value Z is output to the feed servo amplifier 30 via the adder 29.

The adder 29 corrects the feed command value Z. That is, a pulse from the pulse generator 9 for detecting the feed position z of the spindle head 10 is input to the feed deviation counter 31. On the other hand, the pulse from the pulse generator 13 for detecting the rotational position r is input to the feed correction value calculator 32, and the rotational position r is multiplied by P / L from the thread pitch P of the thread processing and the lead L of the ball screw 6, The feed correction value z (r) = P / L × r corresponding to the rotation position r is calculated and output to the feed deviation counter 31. The feed deviation counter 31 calculates a feed deviation E (z) between the feed correction value z (r) and the feed position z of the spindle head 10 and outputs the result to the adder 29. The adder 29 corrects the feed command value Z from the feed command value calculator 28 by the feed deviation E (z), and outputs the corrected feed command value Z (E) = Z + E (z) to the feed servo amplifier 30. I do.

A signal v (z) corresponding to the speed from the tachogenerator 8 is input to the feed servo amplifier 30 as a speed feedback signal, and a feed command value Z ( Drive according to E).

The above control circuit, except for the servo amplifier,
This is a circuit for performing a digital operation, and includes a calculator 22, a rotation deviation counter 23, an acceleration calculator 25, and a jerk calculator 2.
6, adder 27, feed command value calculator 28, adder 29,
The feed deviation counter 31, the feed correction value calculator 32, and the like are realized as internal arithmetic processing using a microcomputer.

The rotation motor 11 is driven by inputting data such as a screw pitch, a feed stroke (tap depth), and a rotation speed from the input device 21, and the feed motor 7 is synchronized with the rotation of the rotation motor 11. Then, it is driven to rotate, and screw processing is performed.

In this embodiment, the feed correction value z calculated from the pulse generator 13 for detecting the rotational position
(R) and the feed deviation E (z) calculated from the feed position z detected by the pulse generator 9, and the feed command value Z is corrected based on the calculated value, so that the steady state between the feed position and the rotational position is obtained. This has the effect of improving the accuracy without causing a significant error.

In the embodiment described above, the rotational deviation E (R)
, The feed command value Z is calculated from the acceleration A (E) and the jerk B (E), but the rotational speed, acceleration and jerk are calculated from other values. It is also possible to control. For example, the actual rotational position r of the main shaft 10 detected by the pulse generator 13
Or the rotation command value R from the computing unit 22.
May be calculated based on

[0027]

As is apparent from the above description, the book
The thread processing device of the present invention has the above-described configuration, and calculates a rotational deviation.
Spindle deviation calculated by the means and its rotation deviation
The rotation calculated by the rotational acceleration calculating means based on
Rolling acceleration and the rotational jerk based on the rotational deviation.
Considering the rotational jerk calculated by the calculating means,
To calculate the corresponding feed command value based on the thread pitch.
Feed command value calculation means, and feed correction value calculation
By means of the screw pitch from the spindle speed.
The feed correction value and feed position detecting means.
Feed deviation from the machine feed position detected by
Calculated by the deviation calculation means, and the value is corrected and fed
The driving command value is calculated by the feed command value calculating means.
The feed command value corrected based on the actual feed position
The motor rotates synchronously, so the spindle rotation position
Good tracking of the machine feed position with respect to
It has the excellent effect of being able to perform high speed screw processing.
You.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of the present invention.

[Explanation of symbols]

7 feed motor 9 pulse generator (feed position detecting means) 11 rotating motor 13 pulse generator (rotating position detecting means) 23 rotation deviation counter (rotation deviation calculating means) 25 acceleration calculator (rotational acceleration calculating means) 26 jerk calculator ( Rotation jerk calculating means) 28 feed command value calculator (feed command value calculating means) 29 adder (correction means) 31 feed deviation counter (feed deviation calculating means) 32 feed correction value calculator (feed correction value calculating means)

Claims (1)

(57) [Claims] 1. A threading device for performing a tapping operation by synchronizing a rotary motor for rotating a main shaft and a feed motor for driving a feed, a rotational position detecting means for detecting a rotational position of the main shaft, and a rotational position thereof. A rotational deviation calculating means for calculating a rotational deviation between the rotational position of the main shaft detected by the detecting means and the rotation command value; a rotational driving means for driving a rotary motor according to the rotational deviation; and a rotational deviation calculating means for calculating the rotational deviation. Rotation deviation value
A rotational acceleration calculating means for calculating the rotational acceleration from the rotational deviation calculated by the rotational deviation calculating means.
Rotation jerk calculating means for calculating the rotational jerk from the rotation deviation calculated by the rotation deviation calculating means,
The rotational acceleration calculated by the rotational acceleration calculating means
And the rotation calculated by the rotation jerk calculating means.
A feed command value calculating means for calculating a corresponding feed command value from the jerk based on the screw pitch, and a rotational position of the main shaft detected by the rotational position detecting means.
Calculates the corresponding feed correction value based on the screw pitch from the position
A feed correction value calculating means, a feed position detecting means for detecting a feed position of the machine, and a feed correction value and a feed position detected by the feed position detecting means.
Feed deviation operation to calculate the feed deviation from the feed position of the machine
Calculating means, and correcting means for correcting the feed command value based on the feed deviation.
And feed according to the feed command value corrected by the correction means.
A screw machining device comprising: a feed drive unit that drives a motor .