JPH11254192A - Control device of linear motor press - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve the excellent pressing without generating any inclination of a slide due to the eccentric load even in a press to be driven by a plurality of linear motors. SOLUTION: In this control device, a slide 4 is arranged on a body frame 1 in a reciprocally movable manner, and linear motors 8-11 are mounted in the moving direction of the slide to reciprocate the slide. Linear scales 12-15 are arranged so as to detect the moving position of the slide 4, and to output the detected positional signal. A control part 20 successively reads the positional data and the speed data from the pattern data in a memory, and controls the drive of the linear motors 8-11 at the speed indicated by the speed data with the position indicated by the positional data as the target position, and the difference between the detected positional data from a predetermined linear scale 12 and the detected positional data from other linear scales 13-15 is calculated, and the positional data and the speed data for the linear motor corresponding to other linear scales are corrected so as to reduce the difference.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a linear motor press machine which presses a slide by reciprocating a slide by a linear motor.

[0002]

2. Description of the Related Art Pressing includes shearing, drawing,
There are various types of processing such as bending and compression, and the slide speed at each moving position of the slide, that is, the press die, is changed according to the type of such press processing or the material and shape of the work. It is desirable.

[0003] For this reason, conventionally, a knuckle press in which coining can be performed by lowering the sliding speed near the bottom dead center, a friction press in which the stroke length and the strength of the striking force can be varied by operating a handle, or Link presses and the like in which the slide speed during non-machining is high and the slide speed during machining is low are manufactured and used.

[0004] However, most of these various press machines are dedicated machines each produced for performing a predetermined press working. Therefore, various press stroke curves can be easily formed by one press machine. There is a demand for a press machine that can be realized by a simple setting change operation. Accordingly, in recent years, a press machine having a structure in which a slide is reciprocated by a linear motor has been developed as a press machine that can arbitrarily and easily change a slide speed or the like at each moving position of the slide.

[0005]

In this linear motor driven press, a plurality of linear motors are arranged along the direction of slide movement to obtain a desired thrust, and reciprocate with a mold attached. The slide is usually slidably guided by a plurality of guide posts or the like. Therefore, when press work is performed by simply driving and controlling a plurality of linear motors and reciprocating the slide, if an eccentric load is applied to the slide due to uneven friction generated between the press die and the workpiece. , Slides tend to tilt,
The problem that good press working cannot be performed was expected.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and provides a good press working without causing a slide tilt due to an eccentric load even in a press driven by a plurality of linear motors. It is an object of the present invention to provide a control device for a linear motor press capable of performing the following.

[0007]

In order to achieve the above object, a control device for a linear motor press according to the present invention is provided in which a slide is reciprocally movable with respect to a main body frame. In a control device of a linear motor press in which a plurality of linear motors are mounted in the direction of movement of a slide, a plurality of linear motors are provided corresponding to the respective linear motors, and detect a movement position of the slide and output a position detection signal thereof. A position detector, pattern data storage means for sequentially storing position data and speed data created per unit time based on a stroke curve diagram when the slide moves, and, during operation, the position data from the pattern data storage means. The speed data is sequentially read, and the position indicated by the position data is set as a target position, and the drive of the linear motor is controlled at the speed indicated by the speed data. Means for calculating a difference between position detection data from one predetermined linear scale and position detection data from another linear case, and for the linear motor corresponding to another linear scale based on the difference. Correction means for correcting the position data and the speed data so as to reduce the difference.

[0008]

Operation and effect of the present invention In the press having such a configuration,
First, a stroke curve (pattern) of a press-formed slide to be performed is written on a stroke curve diagram in which the displacement amount (position) of the slide is plotted on the vertical axis and time is plotted on the horizontal axis.

Next, from this stroke curve diagram, position data for each unit time and velocity data obtained from the time up to that point and the displacement amount are sequentially taken out, and the position data and the velocity data are extracted together with the line number. The position command value and the speed command value are sequentially stored in the pattern data storage means.

During operation, position data and speed data for each time point are sequentially read from the pattern data, and a speed command value is output to a driver of the linear motor. Drive control of the motor. As a result, the slide of the press machine moves at a controlled speed with the commanded position as a target value, that is, according to a program pattern specified in advance, and the upper die fixed to the slide is adjusted to the lower die on the main body frame. , And press working is performed.

At this time, the correction means calculates a difference between position detection data from one predetermined linear scale and position detection data from another linear case.
The position data and speed data for a linear motor corresponding to another linear scale are corrected so as to reduce the difference. Then, the control means outputs a speed command value of the corrected speed data, and drives and controls another linear motor using the corrected position command value as a target position.

As described above, since each linear motor is driven and controlled so that the position detection value from the linear scale corresponding to one predetermined motor becomes the same, the distance between the press die and the workpiece is reduced. Due to uneven friction caused by
Even when an eccentric load is applied to the slide during the press working, the slide is prevented from tilting, and good press working can be performed.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a perspective view of the press machine,
FIG. 2 is a longitudinal sectional view, and FIG. 3 is a plan view thereof. Reference numeral 1 denotes a main body frame of the press machine.
A plurality of thrust bearings 7 are provided, and four guide posts 3 are vertically movably supported thereon. Each of the four guide posts 3 is fixed to the vertically movable frame 5 in the main body frame 1.

A bolster 2 is fixed to an upper portion of the main body frame 1, and a slide 4 is horizontally fixed to tips of four guide posts 3 projecting upward from the main body frame 1 and the bolster 2. In the main body frame 1, a vertically moving frame 5,
Four linear motors 8 to 11 are provided to drive the guide post 3 and the slide 4 up and down. A lower mold (not shown) is fixed on the bolster 2, and an upper mold is fixed on the lower surface of the slide 4, as in a normal press.

The four linear motors 8 to 11 are vertically arranged on the side of the vertically moving frame 5 inside the main body frame 1, and coil sliders (stators) 8a to 11a of the linear motors 8 to 11 are respectively provided. Are fixed to the body frame 1 side, and the magnet plates (movers) 8b to
11b is fixed to the vertical frame 5 side.

Further, four linear scales 12 to 15 are arranged near the guide post 3 on the side of the slide 4 corresponding to the respective linear motors 8 to 11. The stators 12a to 15a of the linear scales 12 to 15 are mounted on the upper part of the main body frame 1 via brackets, and the movers 12b to 15b are mounted near the guide posts 3 on the side of the slide 4. The linear scales 12 to 15 as position detectors for detecting the position of the slide 4 include:
For example, an absolute type is used, and absolute position data is output.

In the press having such a structure, the vertical movement frame 5, the guide post 3, and the slide 4 are vertically driven based on the controlled position data and speed data by the reciprocal drive of the linear motors 8 to 11. The data of the current position output from the linear scales 12 to 15 is fed back and used for high-precision control.

FIG. 4 shows the connection state of the control unit 20 of the press and the linear motor and the like connected thereto. The control unit 20 is configured with a CPU 21 as a main part, and controls the entire operation of the press based on program data stored in a fixed memory in advance. The control unit 20 includes a temporary memory 22 that can be read and written at any time, a display 23,
Switches 24 for inputting or operating various setting values are provided. The memory 22 stores the pattern data of the press operation program written in advance. Further, the memory 22 is provided with a memory area for storing the stroke length, the SPM value (the number of strokes per minute), the die height setting value, the number of press settings, and the like, which are set and input. The set stroke length, SPM value (number of strokes per minute), die height setting value, number of press settings, and the like are displayed on a display 23 that displays a setting screen.

The linear scales 12 to 15 are connected to an interface circuit in the control unit 20 and send the reading of each of the linear scales 12 to 15, that is, the position detection data of the slide 4 to the control unit 20. 4 linear motors 8
11 to 11 are connected to drivers 16 to 19, respectively. Each of the drivers 16 to 19 is connected to an interface circuit in the control unit 20. As the linear motors 8 to 11, for example, AC servomotors (synchronous motors) having a large thrust are used, and their drivers 16 to 19 have, for example, converters and inverters for PWM control. The linear motors 8 to 11 are driven by controlling the current value supplied to the motor according to the output command value.

The control unit 2 serving as the control means and the correction means
0 is the position data and speed read sequentially from the memory 22
Based on the data, the position command value and speed command value are
Output to the data drivers 16 to 19, for example,
A motor 8 is a specific motor, and the linear motor
Position detection value S from scale 12₁ And other linear motors 9
Position from linear scale 13-15 corresponding to ~ 11
Detection value S_Two , S_Three , S _Four If there is a difference between
Based on the difference, position command values for other linear motors 9 to 11
And the speed command value are corrected using a predetermined calculation formula, and the difference
Is controlled so as to reduce.

Next, the operation of the linear motor press having the above configuration will be described. First, prior to the operation of the press, pattern data of a press operation program is stored in the memory 22 in advance.
Is written to.

This pattern data is created from a stroke diagram as shown in FIG. 5, and the stroke diagram is created in an arbitrary shape by taking time on the horizontal axis and the displacement (position) of the slide 4 on the vertical axis. You. The stroke curve diagram in FIG. 5 shows that the SPM value (the number of strokes per minute) is 100, that is, the time of one stroke is 6
Although various patterns in the case of 00 milliseconds and a stroke length of 30 mm are shown, the stroke time and the stroke length can be arbitrarily determined.

From this stroke curve diagram, position data per unit time (for example, every 10 milliseconds when one stroke is divided into 60) and velocity data obtained from the time up to that point and the amount of displacement are taken out. Each time, the position data and the speed data are created as a position command value and a speed command value,
The program pattern data is completed, and such pattern data, that is, data of the position command value and the speed command value for each unit time is stored in the memory 22.

Next, on the control unit 20 of the press machine, the setting of the actual press working operation is performed as shown in the flowchart of FIG. That is, first, the operator causes the display 23 to display the setting screen (step 10).
0), the switches 24 are operated to set and input the stroke pattern number, stroke length, SPM value, die height, and the like (step 110). Then, C of the control unit 20
The PU 21 reads out the program pattern data of the designated pattern number from the memory 22 and stores the data in, for example, the SPM value 100 (the number of strokes per minute is 100 as described above, the position data and the speed data every 10 milliseconds, as described above). ), When the set SPM value is, for example, 80, each speed data is multiplied by a coefficient 0.8,
The speed data is rewritten (step 120), and the setting is completed.

Then, when the screen of the display 23 is switched to the operation screen and the operation switch is turned on, the press machine starts operation. As shown in FIG. The position data and speed data at each time point are read (step 200), and the speed command value is output to the drivers 16 to 19 of each linear motor (step 210). The drivers 16 to 19 output a current controlled by, for example, PWM to each of the linear motors 8 to 11 in accordance with the speed command value, so that the magnet plates (movers) 8b to 11b of the linear motors 8 to 11 When driven, the vertical motion frame 5, the guide post 3, and the slide 4 are controlled so as to descend at the command speed with the position command value of the position data as a target value.

[0026] The movement distance (movement position) is detected by the linear scale 12 to 15, those of the position detection signal is sent to the controller 20, CPU 21 may detect their position value S _1, S _2, S ₃ , captures the S ₄ (step 2
20).

Next, in step 230, the CPU 21
The position detection value S ₁ of the linear scale 12 corresponding to the predetermined linear motor 8 and the other linear scales ₁₃ to ₁
5 is compared with the position detection values S ₂ , S ₃ , and S _4. If there is a difference between them, the process proceeds to step 235 and the difference is calculated as S ₁ −
The differences are calculated as S ₂ = D ₂ , S ₁ -S ₃ = D ₃ , and S ₁ -S ₄ = D ₄ to obtain correction values D ₂ , D ₃ , and D ₄ .

Next, in step 240, the next position data and speed data are read from the pattern data in the memory 22, and in the next step 250, the command values of the linear motors 9 to 11 other than the linear motor 8 as a specific motor are corrected. I do. That is, the speed command value K ₂ for the other linear motors 9 to 11, K _3, K ₄ and position instruction value R _2, R _3, for R _4, the correction value calculated in step 235 D _2, D _3,
The _{D 4, K 2 + F ·} D 2 = K 2, K 3 + F · D 3 =
It corrected using the K _3, K ₄ + arithmetic expression as F · D ₄ = K _4. Here, F is a coefficient. Also, the position command value R
_For R ₂ , R ₃ and R ₄ , R ₂ + D ₂ = R ₂ , R ₃ +
The correction is performed using the arithmetic expression of D ₃ = R ₃ , R ₄ + D ₄ = R ₄ .

Then, returning to step 210, the corrected speed command values K ₂ , K ₃ , and K ₄ are output to the drivers 17 to 19 of the linear motors, and the linear scales 13 to 19 corresponding to the linear motors 9 to 11 are output. The linear motors 9 to 11 are controlled and driven such that the 15 position detection signals become the position command values R ₂ , R ₃ , R ₄ . For the predetermined linear motor 8, a speed command value that is not corrected is output to the driver 16 and drive control is performed. In step 230, the linear scales 13 to
If it is determined that the 15 position detection values S ₂ , S ₃ , and S ₄ are the same as the position detection value S ₁ of the linear scale 12 of the specific motor, the process returns to step 200 without performing the correction, and returns to the next speed data and position. The data is read, and the drive of each of the linear motors 8 to 11 is controlled in the same manner as described above.

As described above, by controlling the driving of the linear motors 8 to 11, the slide 4 and the upper die of the press machine are moved (moved up and down) according to a program pattern specified in advance, and press working is performed. It is. At this time,
Since the linear motors 8 to 11 are driven and controlled so that the position detection values from the linear scales 12 to 15 corresponding to the respective motors become the same, even if an eccentric load is applied to the slide 4 during press working, 4 is prevented from tilting, and good press working can be performed.

In the above embodiment, four linear motors are used. However, the present invention can be implemented with two or more linear motors. Further, another encoder or the like can be used for the linear scale as the position detector.

[Brief description of the drawings]

FIG. 1 is a perspective view of a press showing an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of the press machine.

FIG. 3 is a plan view of the press machine.

FIG. 4 is a block diagram of a control unit including a linear motor and a linear scale.

FIG. 5 is a stroke curve diagram of a press working program pattern.

FIG. 6 is a flowchart showing a setting operation.

FIG. 7 is a flowchart showing an operation control process.

[Explanation of symbols]

 1-body frame 4-slide 8-11-linear motor 12-15-linear scale 20-control unit 21-CPU 22-memory

Claims (2)

[Claims] 1. A control device for a linear motor press, wherein a slide is reciprocally movable with respect to a main body frame, and a plurality of linear motors are mounted in a direction of movement of the slide to reciprocate the slide. A plurality of position detectors provided corresponding to the respective linear motors, for detecting a movement position of the slide and outputting a position detection signal, and a unit time based on a stroke curve diagram when the slide moves. Pattern data storage means for sequentially storing the position data and speed data created for each, and during operation, sequentially read the position data and speed data from the pattern data storage means, and use the position indicated by the position data as the target position to set the speed Control means for controlling the drive of the linear motor at the speed indicated by the data; and position detection data from one predetermined linear scale. The difference between the position data and the position detection data from another linear case is calculated, and the position data and speed data for the linear motor corresponding to the other linear scale are reduced based on the difference so as to reduce the difference. A control device for a linear motor press, comprising: correction means for correcting. 2. A moving frame is provided within the main body frame so as to be reciprocally movable together with a plurality of guide posts, the slide is fixed on the guide posts, and each of the slides is located near a fixing position of the guide posts on the slides. The linear scale is mounted between the main frame and the main frame, and the plurality of linear motors are provided between the main frame and the moving frame so as to correspond to the plurality of guide posts. Control device for linear motor press machine.