JPH073900U - Press load monitor - Google Patents

Abstract

(57) [Summary] [Purpose] To provide an inexpensive and highly accurate press load monitoring device. [Structure] In a press in which a hydraulic chamber 3a for overload protection is provided in a point 3 of a slide 2, a pressure in the hydraulic chamber 3a is detected by a hydraulic sensor 4, and a load applied to the slide 2 by the detected hydraulic pressure. Is converted and displayed on the load display unit 9. By adopting the small and inexpensive hydraulic sensor 4, the price of the monitor itself can be reduced and the detection accuracy can be improved.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a load monitoring device for a press that uses a hydraulic sensor as a detection unit.

[0002]

[Prior art]

 Some conventional presses have a load monitor that displays the load during forming. In the conventional load monitoring device described above, a load cell using a strain gauge is attached to the press body, the strain generated in the press body during molding is detected by the load cell, and this is converted into a load and displayed on the display unit. Has been adopted as

[0003]

[Problems to be solved by the device]

 However, the load cell and the monitor device that converts the strain detected by the load cell into the load and display it are expensive, and since the gain of the load cell must be adjusted for each press, there is a problem that a lot of man-hours are required for the adjustment. there were. In addition, the load cell is large in size, so it requires a lot of space to install, which is also a problem. The present invention has been made in order to solve the above-mentioned conventional problems, and an object thereof is to provide a load monitoring device for a press, which uses a small and inexpensive hydraulic sensor as a detecting portion.

[0004]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the present invention detects the pressure in the hydraulic chamber with a hydraulic sensor in a press provided with a hydraulic chamber for overload protection in the slide point, and changes the detected hydraulic pressure to the slide. The applied load is converted and displayed on the load display section.

[0005]

[Operation] With the above configuration, since a small and inexpensive hydraulic sensor can be used for the detection unit, the price of the load monitoring device can be reduced and the detection accuracy can be improved.

[0006]

【Example】

 An embodiment of the present invention will be described in detail with reference to the drawings. In FIG. 1, reference numeral 1 denotes a press main body, and a slide 2 is provided above the bolster 1a so as to move vertically, and an upper die attached to the lower surface of the slide 2 and a lower die installed on the bolster 1a (both Press molding is performed between (not shown).

A point 3 for transmitting the driving force of a slide driving mechanism (not shown) to the slide 2 is provided on the upper portion of the slide 2 and a hydraulic chamber 3 a formed in the point 3 is provided. An oil pressure sensor 4 for detecting the forming load and an overload protector (not shown) are connected. The hydraulic pressure sensor 4 is composed of a sensor section 4a and an amplifier section 4b for amplifying a signal detected by the sensor section 4a as shown in FIG. 2A, and as shown in FIG. It is designed to output a voltage proportional to the pressure.

On the other hand, a load monitor circuit 5 is connected to the oil pressure sensor 4. As shown in FIG. 1, the load monitor circuit 5 includes a high-speed sampling circuit 6 for sampling the signal detected by the hydraulic pressure sensor 4 at high speed, and a peak value holding circuit for holding the peak value sampled by the high-speed sampling circuit 6. 7. The storage unit 8 stores the hydraulic pressure-load conversion value in advance and the load display unit 9 that digitally displays the load with an LED. The load at the time of molding is displayed as follows.

When the slide 2 is moved down by a slide driving mechanism (not shown) to start molding, the oil in the hydraulic chamber 3a in the point 3 is pressurized and the pressure rises, and the hydraulic sensor 4 detects this. Then, the detection signal is output to the high-speed sampling circuit 6. The high-speed sampling circuit 6 performs high-speed sampling of the signal input from the oil pressure sensor 4, and the peak value hold circuit 7 holds the peak value. Then, the peak value held in the peak value hold circuit 7 is compared with the hydraulic pressure-load conversion value stored in the storage unit 8 to convert the load, and the obtained load is displayed on the load display unit 9. As a result, the load applied to the slide 2 during molding can be easily known by the numerical value displayed on the load display section 9.

If the diameter of the hydraulic chamber 3a in the point 3 is constant, the relationship between the hydraulic pressure and the load has a constant relationship as shown in FIG. 3. Therefore, by detecting the hydraulic pressure in the hydraulic chamber 3a, Therefore, the load applied to the slide 2 can be easily detected. Further, the load monitoring accuracy of the load monitor using the conventional load cell is about ± 5%, whereas the load monitoring accuracy of the device using the hydraulic sensor 4 of the present invention is improved to ± 2%.

[0011]

[Effect of device]

 As described in detail above, this invention uses a hydraulic sensor to detect the load applied to the slide, which can significantly reduce the price compared to the conventional load cell. Since the hydraulic sensor is small, the installation space can be reduced. In addition, since it is possible to monitor the load with high accuracy, when it is used in a press that punches and processes a workpiece, it is possible to easily know the wear state of the mold due to the increase in load, which allows the mold In addition to facilitating management, if a load upper limit is set in advance in the monitor and an alarm is issued when this upper limit is exceeded or the press is automatically stopped, defective products will be generated. It is possible to prevent or operate the press unmanned.

[Brief description of drawings]

FIG. 1 is a block diagram of a load monitor device for a press according to an embodiment of the present invention.

FIG. 2 (a) is a circuit diagram of a hydraulic pressure sensor used in a load monitor device of a press according to an embodiment of the present invention. (B) A diagram showing the characteristics of the hydraulic sensor.

FIG. 3 is a diagram showing a relationship between hydraulic pressure and load.

[Explanation of symbols]

2 ... slide, 3 ... point, 3a ... hydraulic chamber, 4 ... hydraulic sensor, 9 ... load display section.

Claims (1)

[Scope of utility model registration request] 1. In a press having a hydraulic chamber 3a for overload protection provided in a point 3 of a slide 2, the pressure in the hydraulic chamber 3a is detected by a hydraulic sensor 4, and the detected hydraulic pressure causes the slide 2 to move. A load monitor device for a press that converts the applied load and displays it on the load display section 9.