JP3850131B2 - Linear motor press machine bottom dead center control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a bottom dead center control device for a linear motor press.
[0002]
[Problems to be solved by the invention]
In recent years, the slide drive mechanism in press machines is completely different from conventional mechanical presses such as crank presses and link presses, and the development of linear motor press machines that reciprocate the slide using a linear motor has been promoted. ing.
[0003]
The present inventors conducted various tests using a prototype of a linear motor press machine. It was found that it was difficult to maintain the bottom dead center accuracy by shifting from the dead center reference position.
[0004]
In view of the above problems, the present invention has been made for the purpose of sufficiently maintaining the bottom dead center accuracy even when the movable member is thermally expanded.
[0005]
[Means for Solving the Problems]
The bottom dead center control device of the linear motor press machine of the present invention includes a movable member to which a slide is fixed, a linear motor fixed between the movable member and a main body frame, and reciprocating the movable member, and the slide Alternatively, an absolute position detector that is disposed between the position near the slide of the movable member and the main body frame and detects the absolute position of the reciprocating section of the slide, and an optimum pattern of slide behavior stored in advance. The command value to be output to the driver of the linear motor is read, the command value is output to the driver, and then the absolute position data of the slide is fetched from the absolute position detector. It is repeatedly determined whether the absolute position matches the command position of the command value until it matches the command position of the value. The command value to be output to the driver next time is read out, and a series of processes of outputting the command value to the driver And a control circuit that controls the linear motor so as to maintain the bottom dead center actual position at the bottom dead center reference position .
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 is a perspective view of a linear motor press, FIG. 2 is a longitudinal sectional view thereof, and FIG. 3 is a plan view thereof.
[0007]
1 to 3, reference numeral 1 denotes a main body frame of a linear motor press machine. Four thrust bearings 6 are provided on the inner bottom of the main body frame 1, and four thrust bearings 7 are further provided on the upper portion. A book post (movable member) 3 is supported so as to be movable up and down. Each of the four guide posts 3 is fixed to the vertically moving frame 5 in the main body frame 1.
[0008]
The bolster 2 is fixed to the upper part of the main body frame 1, and the slide 4 is fixed horizontally to the tips of the four guide posts 3 protruding upward from the main body frame 1 and the bolster 2. In the main body frame 1, four linear motors 8 to 11 are arranged to drive the vertical movement frame 5, the guide post 3, and the slide 4 up and down. Similar to a normal press, a lower die (not shown) is fixed on the bolster 2, and the upper die is fixed to the lower surface of the slide 4.
[0009]
The four linear motors 8 to 11 are respectively arranged in the vertical direction on the side of the vertical movement frame 5 inside the main body frame 1 and are coil slides of the linear motors 8 to 11 (in this embodiment, they are stators). ) 8a to 11a are fixed to the main body frame 1 side, and magnet plates (being movable elements in this embodiment) 8b to 11b of the linear motors 8 to 11 are fixed to the vertical movement frame 5 side. Further, four linear scales (absolute position detectors) 12 to 15 are disposed in the vicinity of the guide post 3 on the side of the slide 4 corresponding to the linear motors 8 to 11. The stators 12 a to 15 a of the linear scales 12 to 15 are attached to the upper part of the main body frame 1 via brackets, and the movers 12 b to 15 b are attached to the vicinity of the guide posts 3 on the side of the slide 4. For example, an absolute type is used for the linear scales 12 to 15, and absolute position data is output. Note that the stators 12 a to 15 a or the movers 12 b to 15 b of the linear scales 12 to 15 may be directly attached to the slide 4.
[0010]
In the linear motor press machine having such a structure, the reciprocating motion of the linear motors 8 to 11 causes the vertically moving frame 5, the guide post 3, and the slide 4 to move up and down integrally at a controlled speed and stroke, Based on the movement position data output from the linear scales 12 to 15, the movement of the slide 4 is controlled with high accuracy.
[0011]
FIG. 4 shows a connection state of a control board (control circuit) 20 of the linear motor press machine and a linear motor connected thereto. The control circuit 20 is configured with the CPU 21 as a main part, and controls the operation of the press machine based on program data stored in advance in a fixed memory. The control circuit 20 is provided with a temporary memory 22 that can be read and written as needed, a display 23, and switches 24 for inputting or operating various setting values. The memory 22 is provided with a memory area for storing pre-registered press operation pattern program data, set and inputted stroke length, SPM value (number of strokes per minute), die height set value, number of press settings, and the like. It is done. The set stroke length, SPM value, die height set value, number of press settings, etc. are displayed on the display 23 that displays the setting screen.
[0012]
The linear scales 12 to 15 are connected to an interface circuit in the control circuit 20 and send readings of the respective linear scales 12 to 15, that is, position detection data (absolute position data) of the slide 4 to the control circuit 20. Drivers 16 to 19 are connected to the four linear motors 8 to 11, respectively, and the drivers 16 to 19 are connected to an interface circuit in the control circuit 20. During operation, for example, an AC servo motor (three-phase synchronous motor) system having a large thrust is used as the linear motors 8 to 11, and the drivers 16 to 19 have, for example, servo amplifiers and are output from the control circuit 20. The linear motors 8 to 11 are driven according to the command value.
[0013]
Next, processing according to the present invention executed in the control circuit 20 will be described based on the flowchart shown in FIG.
[0014]
First, the control circuit 20 determines the command value (target position (command position) to be reached by the slide 4) to be output to the drivers 16 to 19 from the optimum pattern of the behavior of the slide 4 stored in advance. And the speed data of the slide 4 is read out (step 101), and the command value is output to the drivers 16 to 19 (step 102). Next, the absolute position data of the slide 4 is fetched from the linear scales 12 to 15 (step 103), and it is determined whether or not the absolute position matches the command position of the command value (step 104). The determination is repeated until they match. When the absolute position coincides with the command position, the determination result of step 104 is reversed to “YES”, and it is determined whether or not the drive is stopped (step 105). If the drive is not stopped, the process returns to step 101 and is output next time. The power command value is read and this command value is output (step 102). And step 103-step 105 are performed in order. Thereafter, steps 101 to 104 are repeatedly executed until the drive is stopped, and the slide 4 is reciprocated based on the command value of the optimum pattern of the behavior.
[0015]
Here, when the mounting part of the linear motors 8 to 11 generates heat due to continuous operation of the press machine, and the guide post 3 starts to expand due to this heat generation, the absolute position of the slide 4 output by the linear scales 12 to 15. Data starts to change. However, since the control circuit 20 executes the process of outputting the next command value after confirming that the absolute position of the slide 4 has reached the command position as described above, the linear scales 12 to 15 are executed. The bottom dead center position of the slide 4 is maintained even if the absolute position data from is changed. In the above embodiment, the linear scales 12 to 15 are disposed on the slide 4, but may be disposed near the slide of the guide post 3.
[0016]
【The invention's effect】
According to the present invention, the bottom dead center accuracy can be sufficiently maintained even when the movable member is thermally expanded.
[Brief description of the drawings]
FIG. 1 is a perspective view of a linear motor press machine to which a bottom dead center control apparatus according to an embodiment of the present invention is applied.
FIG. 2 is a longitudinal sectional view thereof.
FIG. 3 is a plan view thereof.
FIG. 4 is a block diagram of an electric system of the linear motor press machine.
FIG. 5 is a flowchart showing processing contents of a control circuit.
[Explanation of symbols]
1 Body frame 3 Guide post (movable member)
4 Slide 8-11 Linear motor 12-15 Linear scale (absolute position detector)
20 Control panel (control circuit)

Claims (1)

A movable member to which the slide is fixed;
A linear motor fixed between the movable member and the main body frame and reciprocating the movable member;
An absolute position detector that is disposed between the slide or a position near the slide of the movable member and the main body frame, and detects an absolute position of a reciprocating section of the slide;
A command value to be output to the driver of the linear motor is read out from the optimal pattern of the slide behavior stored in advance, and this command value is output to the driver, and then the slide is output from the absolute position detector. Until the absolute position matches the command position of the command value, it is repeatedly determined whether the absolute position matches the command position of the command value, and the absolute position is the command value of the command value. When the position coincides with the position, a command value to be output to the driver next time is read, and a series of processes of outputting the command value to the driver is executed, whereby the bottom dead center of the slide A control circuit for controlling the linear motor so as to maintain the actual position at the bottom dead center reference position . Bottom dead center control device.

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