JPS61169199A - Press machine - Google Patents

Abstract

PURPOSE:To enable the press work of high accuracy with controlling a bottom dead point to become at constant position by varying a press speed. CONSTITUTION:A press machine has the bottom dead point position detecting part 6 to equip the position detecting sensor 16 to detect the bottom dead point position of a sliding part 3 and the arithmetic control part 8 to perform the control of a slide driving part 7 based on the output signal SA transmitted from this detecting part. The position detecting sensor 16 is induced to the approaching proximity plate 19, the detecting signal SA is outputted to a peak value holding circuit 21 via amplifier 20, the peak value to show the bottom dead point is held, the signal SB to show the peak value is inputted into A/D convertor 22, the signal SB is converted into A/D and the digital signal SC is inputted into microcomputer 23. The computer 23 calculates the difference DELTAP between the bottom dead point position P and reference bottom dead point position PO. And if the difference DELTAP shows positive, namely the bottom dead point shows a rising tendency the control signal SM such as increasing the press speed by 50spm in case of rising about 30mum, for instance is impressed on a motor part 12 by the preset empirical formula.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a press machine capable of high-precision press processing.

[Technical background of the invention and its problems]

In general, in a press machine, there are always several joints that convert rotational power into reciprocating linear motion, and the total clearance, which is the sum of all the clearances (play) between them, has a large effect on press accuracy.

For example, if a press with a large overall clearance is used during punching, a so-called breakthrough occurs in which the elastic deformation of the frame returns to its original state the moment the material separates.
(through), the punch enters the die hole, causing wear and damage to the die. This phenomenon occurs particularly when the bottom dead center position is inappropriate. By the way, this bottom dead center position changes depending on the driving time as shown in FIG. That is, at the beginning of the operation, the slide section of the press machine locally generates heat, causing the ram section to thermally expand, causing the bottom die to descend. However, after a certain amount of operating time has elapsed, the heat of the slide portion diffuses to the surroundings and the frame portion thermally expands, causing the bottom dead center to rise. The fact that the bottom dead center changes as the operating time elapses in this manner indicates that the press accuracy also varies as the operating time elapses.

In the past, various methods have been used to maintain the lower dead puller in a fixed position.

The main ones are (a) providing a mechanism to change the ram position during press operation; (b) Maintaining the temperature of the lubricating oil constant and stabilizing the temperature of the press machine.

However, the former method (a) causes a decrease in the rigidity of the press machine and shortens the life of the mold, and the latter method (a)
The method → requires large-scale equipment for heating and cooling the oil, and it takes 1 to 2 hours for the temperature of the press machine to stabilize.

[Purpose of the invention]

An object of the present invention is to provide a press machine that has a bottom dead center position control function and can maintain the bottom dead center at a constant position during press operation.

[Summary of the invention]

The bottom dead center position of the slide portion is controlled to a constant position by adjusting the press speed.

[Embodiments of the invention]

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

1 and 2 show the press machine of this embodiment. This press machine has a frame part (1
), a slide part (3) that is attached to this frame part (1) and moves up and down in the direction of arrow (2), a bed part (5) to which the lower mold (4) is attached, and a bottom part of the slide part (3). The bottom dead center position detection part (6) detects the dead center position, and the slide part (
3) and an arithmetic control unit (8) that controls the slide drive unit (force) based on the output signal SA from the bottom dead center position detection unit (6). The frame part (1) has a pair of mutually parallel columns +9), (9).
The inner surfaces (9a), (9a) facing each other to f9) are
This serves as a guide surface for the slide section (3). Furthermore, the slide part (3) has arrows (2) in the columns (9), (9).
It consists of a ram (1@) which is slidably mounted in the ) direction, and an upper die aυ which is fixed to the ram a[.

This upper die α1) has a punch and is adapted to perform punching together with the die of the lower die (4). Further, the slide drive section (7) includes a motor section a built in the frame section (1) and a crank mechanism (one end of which is connected to the slide section (3) and which converts the rotation of the motor section αa into reciprocating motion. 13). In addition, the bed part (
5) is provided adjacent to the frame part (1), and has a bolster (14) fixedly installed on the upper surface for positioning the lower mold (4).On the other hand, the bottom dead center position detection part (6) is , a proximal body αQ attached to the lower end of the ram frame, and a bolster (14)
and a position detection sensor α6), such as a high-rise waveform proximity switch, which is identified to face the proximity object (I5). The proximal body a9 includes an L-shaped fixing metal fitting (17) protruding from the ram α0, a rod-shaped body 08) vertically installed on this fixed mold (17), and a barrel of this rod-shaped body a. It consists of a metal proximity plate 01 which is connected to the lower end so that its main surface is a horizontal plane. This proximity plate I has a ram (10
) is arranged so as to face the position detection sensor 00 at a distance of, for example, lQ ynx when it is at the bottom dead center position.

The position detection sensor aO has a detection coil that generates a magnetic field that induces an eddy current in the proximity plate 01, and a high-frequency oscillation circuit that supplies a high-frequency current to this detection coil. Based on impedance changes caused by eddy currents, an output signal SA is output indicating the distance between the proximity plate (11 and the position detection sensor 06), that is, the bottom dead center of the ram a. ) consists of an amplifier (a) connected to the output side of the position detection sensor aO, a peak value hold circuit (21) connected to the output side of this amplifier and holding the peak value indicating the lower dead end, and a peak value hold circuit (21) connected to the output side of this amplifier An analog-to-digital (A/D) converter connected to the output side of the value hold circuit (21) is connected to the output side of the A/D converter (22), and also sends a control signal SM to the motor section 02. It consists of a microcomputer (c) that outputs the following.A calculation program, which will be described later, is stored in this microcomputer (c).

Therefore, in the press machine having the above configuration, when the bottom dead center of the ram 01 is in the proper position, the peak value hold circuit (2
The value held at υ, ie, the reference bottom dead center position PO, is stored in the microcomputer (23). Next, a workpiece (not shown) is placed on the lower mold (4), the motor section is started, the slide section (3) is lowered via the crank mechanism (13), and the upper mold ( The workpiece is sheared using the punch (11) and the die (4).

At this time, the position detection sensor 06) detects the approaching proximity plate (
11, a detection signal SA is outputted to a peak value hold circuit (21) via an amplifier (20).

Then, in this peak value hold circuit eI), the peak value indicating the bottom dead center is held, and a signal indicating the peak value is output to the 8B cancer small converter (2). ), the signal SB is converted to Vl) and the digital signal SC is output to the microcomputer (c).

This digital signal SC is sent to a microphone (lj pin
By the way, FIG. 3 shows that the bottom dead center changes depending on the press speed C]4-minute stroke number: Spm). In other words, the amount of change in the bottom dead center due to the passage of press operation time (approximately 100 μm in Fig. 4) is calculated by changing the press speed to 150 s.
This shows that it can be controlled by adjusting within the pm range. Therefore, the microcomputer (2) calculates the difference △P between the bottom dead center position It F and the reference bottom dead center position PO. If it is, then according to the preset experimental formula based on Figure 3, for example, the temperature has increased by about 50g.
A control signal SM is applied to the motor circle to increase the pm press speed. On the other hand, if the above difference △P is negative, that is, the bottom dead center shows a downward trend, the above experimental formula indicates that the control signal decreases the press speed by, for example, B', f4.3ospm. Apply SM to the motor section (1z).Furthermore, if △P is outside the upper and lower limit values PU and PLO, that is, if the bottom dead center change occurs suddenly, it is determined that an abnormality has occurred. An alarm signal for temporarily interrupting the press work is output to an alarm device (not shown), and an alarm sound is generated.

In this way, the press machine of this embodiment controls the bottom dead center at a constant level with a relatively simple device, which enables high-precision press processing and stabilizes press quality. Furthermore, abnormalities in the press can be detected at the same time, and together with the fixed position control of the bottom dead center, it is possible to prevent abnormal wear and damage of the mold, decrease in press processing accuracy, etc., and improve the reliability of press processing. do.

Note that the detection of press abnormality in the above embodiment may be omitted, and only the bottom dead center control may be performed.

Further, the position detection sensor may be of a capacitive type, a magnetic type (using a reed switch), or the like. Alternatively, a contact type sensor such as a differential transformer may be used. Furthermore, the proximity body a9 may be attached to the upper mold (11).
The peak value hold circuit in the above embodiment may be omitted, the detection signal SA may be temporarily stored in the data memory section via an A/D converter, and the bottom dead center may be determined by software of a microcomputer.

[Effects of the invention-]

The press machine of the present invention controls the bottom dead center to be at a constant position by changing the press speed, making it possible to perform high-precision press processing, stabilizing press quality, and preventing mold problems. Wear and breakage can be prevented, the life of the mold can be extended, and the reliability of press working can be improved.

[Brief explanation of the drawing]

Fig. 1 is a 11j side view of a press machine according to an embodiment of the present invention, Fig. 2 is a diagram showing the correct view, and Fig. 3 is a graph showing the relationship between press speed and bottom dead center. FIG. 4 is a graph showing the relationship between press operation time and bottom dead center. (1)...Frame part, (a)"'slide part, (4
)...lower mold, (5)...bed part, (6)
...Bottom dead center position detection unit, (force...slide drive unit, (8)...calculation control unit, (I))...upper mold. Fig. 1 Fig. 3 JP-A-6-1 169199 (4) Figure 4 Figure 2

Claims (2)

[Claims] (1) A slide part to which the upper mold is attached, a frame part that supports the slide part so that it can move up and down, a slide drive part that drives the slide part up and down, and a lower mold that performs press working together with the upper mold are attached. a bottom dead center position detection unit that detects the bottom dead center position of the slide portion;
Based on the detection signal indicating the bottom dead center position outputted from the bottom dead center position detection section, the deviation of the bottom dead center position from the reference position where the press working is properly performed is determined. an arithmetic control unit that outputs a control signal to the slide drive unit to decrease the press speed of the slide unit when the shift is shifting to the side of the upper mold, and to increase the press speed when the shift is shifted to the upper mold side; A press machine comprising: (2) The calculation control unit outputs a machining stop signal when the deviation of the bottom dead center position from the reference position is outside a preset normal range.
Press machine described in section.