JPH0926366A - Load measuring equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a load measuring equipment of which the cost of production is low, for which an inexpensive composite material can be used in conformity with the use and which can also be buried in a structure and is capable of measuring a load immediately or at a necessary time. SOLUTION: A piezo thin film 8 is formed in close contact with one end face of an upper block 7 which is a strain generating body formed out of a material having rigid properties. The end part on the piezo thin film 8 side of this upper block is fixed to a ram 2 being one of two members to which a load is to be applied, and this ram 2 is provided with an electric signal impression pin 6 which is brought into contact with the piezo thin film 8 and impresses an electric signal on the film so as to make it generate ultrasonic vibration. The load is applied by a lower block 9 to the other end part of the upper block 7 and the time of reflection of the ultrasonic vibration is measured. Thereby, the load between the upper block 7 and the block 9 is measured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
An ultrasonic wave is generated by applying an electric signal to the ultrasonic transducer of the strain generating body attached to one of the members, and the load between the other member causes the ultrasonic wave to be generated due to the deformation of the strain generating body. The present invention relates to a load measuring device that measures the time until reflection and measures the load between two members.

[0002]

2. Description of the Related Art Conventionally, as a means for measuring a load between two members, a portion having a large amount of deformation with respect to the load is provided between the two members, and a strain gauge is attached to the portion to electrically measure the strain amount of the strain gauge. In another method, an elastic member such as a spring that is deformed by a load is interposed between the two members, and a dimensional change due to the load of the elastic member is measured to add between the two members. A method of measuring the load is also known.

[0003]

The conventional method of electrically measuring a load with a strain gauge is difficult to dispose because the strain gauge is expensive to incorporate, and for example, strain is measured to measure strain generated in a structure. The method of using a gauge and leaving it in the structure increases the cost of the structure.

Incorporating a strain gauge is not suitable for mass production, and forming a portion having a large amount of deformation with respect to the load weakens the strength of the structure, and the load is measured by the dimensional change of the elastic member. The method has a problem that the elastic member cannot be a part of the structure.

The present invention is intended to solve the above-mentioned problems, and an object of the present invention is to reduce the production cost and to use an inexpensive synthetic material according to the application, and to construct a structure. The purpose is to provide a load measuring device that can be buried inside and can measure the load immediately or at a required time.

[0006]

The load measuring device of the present invention is intended to achieve the above-mentioned object. The means is such that a piezoelectric thin film is formed on one end face of a strain-generating body made of a rigid material. An ultrasonic transducer is closely formed, and the end of the strain generating body on the ultrasonic transducer side is fixed to one member between two members to which a load is applied. Is provided with an electric signal applying member for applying an electric signal to the ultrasonic transducer to generate ultrasonic vibration, and the other end portion of the strain generating body is provided with the other member between the two members to which the load is applied. It is characterized in that the load between the fixed member and the load member is measured by applying a load and measuring the reflection time of the ultrasonic vibration.

Further, the other member is used as a workpiece, and one end surface portion of the flexure element is attached as a working member such as a ram which operates one member with respect to the workpiece,
The processed member is provided with an electric signal applying member that receives an electric signal obtained by converting the reflected ultrasonic wave while applying an electric signal by contacting the ultrasonic transducer formed on the end face. Is characterized in that the end face part of is formed on a tool part for processing a member to be processed, and the processing load of the machine tool is measured while the member to be processed is processed by this tool part.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Next, as an embodiment of the present invention, an embodiment of a press machine for performing desired forming by pressing a plate material shown in FIGS. 1 and 2 will be described below. As shown in the figure, this press machine is equipped with a bed 1 to which a lower die for pressing a plate material or the like, which is a workpiece, is attached, and an upper die for pressing to this bed, and to attach the upper die to the bed. It is composed of a ram 2 for raising and lowering the mold.

The lower side of the ram 2 is formed in a T-shaped groove 3, and the upper head mounting body 5 is mounted by inserting the enlarged head 4a of the mounting bolt 4 into the groove 3, and the ram 2 is mounted. Two
And the upper die mounting body 5 constitute a processing member. The lower side of the upper die mounting body 5 is also formed in the T-shaped groove 5a, and an electric signal is output to the central portion thereof and ultrasonic waves are generated. Is applied, an electric signal applying pin 6 for converting the ultrasonic wave into an electric signal is attached with its tip facing downward.

The upper die 7 which is a low-flexure element is provided with mounting portions 7a which are inserted into the T-shaped grooves 5a of the upper die mounting body 5 and are attached to the upper die mounting body 5 on the left and right of the upper surface. A piezoelectric thin film 8 which is an ultrasonic oscillator is vapor-deposited in a state in which the crystal is slanted in the middle of the left and right mounting portions 7a, and the upper die 7 is mounted on the upper die mounting body 5 by the mounting portion 7a. When
The piezoelectric thin film 8 contacts the tip of the electric signal applying pin 6.

A convex mold 7b in which both sides of the upper mold 7 project at right angles.
Between the upper mold 7 and the lower mold 9, the lower mold 9 is provided with the concave mold 9a formed in the concave mold 9a that bends the plate material sandwiched between the upper mold 7 and the lower mold 9 at a right angle. Upper mold 7 in the center
The punching die 7c is inserted into the punching die to punch a hole in the plate material.
b.

A pulsed voltage is sent to the electric signal applying pin 6, and a time difference between the sending voltage and the pulsed voltage detected by the electric signal applying pin 6 is sent. A measuring device 10 provided with a display unit that detects the load, converts the load, and displays the load applied to the plate material that is the workpiece is connected.

When a plate material is inserted between the upper die 7 and the lower die 9 of this press machine and the ram 2 is lowered, the convex die 7 of the upper die 7
Between the a and the concave mold 9a of the lower mold 9, the left and right sides of the plate material are bent upward under the bending pressure, and the middle part of the left and right upward bent parts is a punching die. Shearing pressure is applied between the periphery of 7c and the hole die 9b to perform perforation and the press descent on the plate material is completed.

During the pressing process, the measuring instrument 10 outputs a pulsed voltage signal to the electric signal applying pin 6, and the electric signal is applied from the electric signal applying pin 6 to the piezoelectric thin film 8 of the upper die 7, This electric signal becomes ultrasonic vibration by the piezoelectric thin film 8 and is propagated in the axial direction within the upper mold 7.

The propagated ultrasonic wave is reflected by the lower end surface of the upper die 7 and hits the piezoelectric thin film 8. Therefore, the ultrasonic vibration is converted into an electric signal again by the piezoelectric thin film 8, and this electric signal is converted into an electric signal. Since the signal is transmitted to the signal applying pin 6, the measuring instrument 10 detects this.

The measuring instrument 10 precisely measures the time lag between the output of this electric signal and the detection of the electric signal by reflected ultrasonic waves, calculates the load from the change based on this measurement, and displays it on the display unit. Therefore, the load of the press work by the upper mold 7 is determined.

In the above-mentioned embodiments, the case where it is adopted in the press machine in which the compressive pressure is applied to the upper die 7 which is the strain generating body has been described. In addition to this, the pulling force and the shearing force are applied to the strain generating body. Even when a force or bending moment is applied,
The internal stress can be known by measuring the ratio of longitudinal wave and transverse wave of ultrasonic waves, and it can be used for other than press machines.

[0018]

As described above, according to the present invention, the piezoelectric thin film which is the ultrasonic transducer of the strain generating body can be continuously vapor-deposited at a low temperature, so that the production cost can be reduced, and the piezoelectric thin film can be used in a wide range including disposables. Therefore, it can be adopted without significantly increasing the cost.

Depending on the size of the load and the application, it is possible to select a material having a rigidity corresponding to this, and the cost can be reduced for the load measuring device by the selection, and the cost can be reduced even for single use such as embedding in a structure. It does not cause great difficulty such as the rise of.

Therefore, not only measurement during construction such as machining of a work piece or construction of a structure, but also connection to a measuring instrument in real time and at a necessary time such as measurement of load after completion of construction of a structure. A wide range of choices such as free measurement is possible.

[Brief description of drawings]

FIG. 1 is an overall side view of an embodiment according to the present invention. It is a longitudinal section of the important section.

FIG. 2 is a longitudinal sectional view of a main part of the above.

[Explanation of symbols]

 2 Ram 6 Electrical signal application pin 7 Upper mold 7b Convex 7c Stamping 8 Piezo thin film 9 Lower 9a Recess 9b Hole

Claims (2)

[Claims] 1. An ultrasonic transducer such as a piezo thin film is closely formed on one end surface of a strain-generating body made of a rigid material, and the end portion of the strain-generating body on the side of the ultrasonic transducer is formed. Is fixed to one member between two members to which a load is applied, an electric signal is applied to the member by contacting the ultrasonic vibrator, and an electric signal is applied to the ultrasonic vibrator to generate ultrasonic vibration. Is provided and a load is applied to the other end of the flexure element by the other member between the two members to which a load is applied, and the reflection time of the ultrasonic vibration is measured, thereby A load measuring device characterized by measuring a load. 2. The other member is a member to be machined, and one end surface of the flexure element is attached as a member to be machined, such as a ram, which operates with respect to the member to be machined.
The processed member is provided with an electric signal applying member that receives an electric signal obtained by converting the reflected ultrasonic wave while applying an electric signal by contacting the ultrasonic transducer formed on the end face. 2. The load measurement according to claim 1, wherein the end face of the tool is formed on a tool part for processing a member to be processed, and the processing load of the machine tool is measured while the member to be processed is processed by the tool part. apparatus.