JPS599542A - Load displacement measuring apparatus - Google Patents

Abstract

PURPOSE:To make it possible to measure the tensile rigidity at an arbitrary part simply, by constituting a compressing piece, which is contacted with a material to be measured and compresses the material, by a load to voltage converter and an acceleration to voltage converter; integrating the speed signal from the acceleration converter twice; thereby converting the signal to a displacement signal. CONSTITUTION:When a compressing piece 11 is compressed to a door panel 8, an electric signal is obtained from a load to voltage converter 3 in response to a load. An acceleration signal is obtained from an acceleration to voltage converter 12 in response to deforming acceleration of a panel 8. In order to integrate the signal twice and to convert the signal to a displacement signal, the load signal from a preamplifier 14 is compared with a preset value in a comparator 17. When the signal exceeds the preset value, an operating circuit 20 is operated, and a control circuit 19 is controlled so that the measured value is outputted from an amplifier circuit 16. The load signal from the preamplifier 14 and the displacement signal from the operating circuit 20 are inputted to an XY recorder 10 through the amplifier 16 and recorded as the load displacement curve diagram of the panel 8.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a load displacement measuring device for measuring the tensile rigidity of vehicle body panel parts such as automobile doors.

As a conventional load displacement measuring device, there is one shown in FIG. 1, for example.

That is, the base of the arm 2 is fixed near one side edge of the surface plate 1, and the lifting body 5 is moved up and down via a gearbox 7 consisting of a rack and a pinion driven by a drive motor 6 at the tip of the arm 2. It is installed so that it can be raised and lowered freely in the direction (
=, displacement/voltage converter (linear potentiometer, etc.) 4
The fixing part 4a is attached to the top of the elevating body 5.
A voltage converter (such as a strain gauge) 3 is fixed, and a sliding portion 4b of the displacement/voltage converter 4 is attached to the side edge of the elevating body 5.

Then, driving the drive motor 6 (=therefore the load/
The indenter consisting of the voltage transducer 6, the sliding part 4b of the displacement/voltage transducer 4, and the elevating body 5 is lowered, and the surface plate 1! The object to be measured, the door panel 8 of an automobile, placed horizontally on the R, is pressed, and while the measurement point is displaced, the outputs of the load/voltage converter 6 and the displacement/voltage converter 4 are transmitted to the XY recorder via the amplifier 9. 10, the relationship between the displacement of the door panel 8 and the load is recorded as shown in FIG. 2, for example.

In addition, in Fig. 2, the solid line indicates the load and
The displacement diagram and the broken line are load/displacement diagrams for a portion with low tensile rigidity, and in both cases, the portion indicated by the rising arrow indicates the time of loading, and the portion indicated by the descending arrow indicates the time of unloading.

However, such conventional load displacement measuring devices have an indenter support structure using a surface plate 1 and a highly rigid arm 2 fixed to the surface plate 1, so it is difficult to handle small parts such as removable door panels. Although there were no problems with the measurement, there was a problem in that it was difficult to easily measure the tension rigidity of each part such as the roof, foot, trunk, fender, etc. without disassembling the vehicle.

This invention was made in view of the above points, and can be used separately from a measurement indenter surface plate, etc., and can be pressed against any part of the outer panel of a car body to measure the tension rigidity of that part. The purpose is to make it possible.

Therefore, the load displacement measuring device according to the present invention is constructed by directly connecting a load/voltage converter and an acceleration/voltage converter f as an indenter, and instead of the displacement signal obtained by the conventional displacement/voltage converter, The above object is achieved by integrating the acceleration signal generated during deformation twice to obtain a displacement signal.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings FIG. 6 and subsequent drawings.

FIG. 3 is a block diagram showing an embodiment of the present invention, and parts corresponding to those in FIG. 1 are given the same reference numerals.

First, to explain the configuration, in the automobile door panel 8 consisting of an outer panel 8a and an inner panel 8b, an indenter 11 that presses the outer panel 8a from the direction of arrow A is a load/voltage converter that converts the load applied to the outer panel 8a into an electrical signal. As shown in FIG. These are directly connected to each other to constitute one indenter 11.

The load/voltage converter 3 is a so-called load cell, and converts a force or force into an electrical output using, for example, a strain gauge.

The acceleration/voltage converter 12 similarly uses a strain gauge to convert the acceleration of a running vehicle or the like or the vibration of the vehicle body 2 machine or the like into an electrical output.

The hard rubber 16 is replaceable as shown in FIG.
The shape can be changed depending on the object to be measured.

The load signal from the load/voltage converter 6 is transmitted to the preamplifier 14 via the coil i3a, and the acceleration signal from the acceleration/voltage converter 12 is transmitted to the preamplifier 15 via the coil 1' 12a, where they are amplified. Ru.

The output of the preamplifier 14 is input to an amplifier circuit 16 and also to a comparator 17 (2), where it is compared with a reference value set by a load setting circuit 18. The output of this comparator 17 is given to an output control circuit 19. .

The acceleration signal output from the preamplifier 15 is integrated twice by an arithmetic circuit 20 operated by an output control circuit 19 and converted into a displacement signal, which is input to the amplifier circuit 16 .

4- The amplifier circuit 16 is controlled by an output control circuit 19, and its output is given to the XY recorder 10.

Next, the load displacement measuring operation according to this embodiment will be explained.

When the indenter 11 is carried and pressed against the outer panel 8a of the door panel 8, a voltage signal is obtained from the load/voltage converter 6 as a load signal in accordance with the load applied to the outer panel 8a. Further, a voltage signal is obtained as an acceleration signal from the acceleration/voltage converter 12 in accordance with the deformation acceleration of the outer panel 8a.

In order to integrate the acceleration signal twice and convert it into a displacement signal, it is necessary to set an initial value. In this example, the load signal has a certain set value Wo (for example, 100, P~300y
-) is used as the starting point for transformation.

For this purpose, the comparator 17 is used to compare the load signal from the preamplifier 14 with the value for the load WO preset by the load setting circuit 18, and when the value exceeds the value, the arithmetic circuit 20 is activated and amplified. The output control circuit 19 performs output control so that the measured value is output from the circuit 16.

In the conventional example shown in FIG. 1, the XY recorder 10 receives a load signal from the preamplifier 14 and a displacement signal obtained by converting the acceleration signal from the preamplifier 15 from the arithmetic circuit 20 via the amplifier circuit 16. Similarly, the relationship between the displacement of the outer panel 8 and the load can be recorded as a load/displacement diagram.

The operation of this embodiment will be further explained in detail with reference to FIGS. 5 and 6.

FIG. 5 shows how the indenter 11 is inserted into the outer panel 8a of the door panel 8.
The elapsed time t (seconds) when a load is applied while contacting and pressing the outer panel 8a, and the load applied to the outer panel 8a (
This is an example showing the relationship between the state of increase (a) in Ky) and the change (b) in the displacement amount ('M) of the outer panel 8a according to the load, where the displacement is a calculated value from the acceleration.

Now, the time when the indenter 11 contacts the outer panel 8a is t.
When =0, when 1=11, the force pushing the outer panel 8a becomes the set load WO, and at this time, the calculation circuit 20 starts calculating the two-time integration of the acceleration signal. At this set load WO, although there is a slight displacement, it is ignored and the amount of displacement is taken as the capacity.

And it becomes as follows.

At t=tz, the load is about 7Ky and the displacement is about 19Ky t=t3
Then, the load is about 12 and the displacement is about 61. At t=t4,
Figure 6 shows the output of the XY recorder 10 when the load is about 15 mm and the displacement is about 9.0 mm.
The load of the load/electric ratio converter 6 is 100y- to 300y-
When the set load (Wo) of approximately Recorder 101: Therefore, it is output.

FIG. 6 recorded in this way is the outer panel 8a.
This is a load/displacement curve representing the measurement results of , and the tensile rigidity of the outer panel 8a can be evaluated using this diagram.

In the above embodiment, an example was described in which the outer panel of the door spring 7-le was used as the object to be measured, but the displacement measuring device according to the present invention can be used to measure the displacement of any panel member.

As explained above, according to the present invention, the indenter that comes into contact with and presses the object to be measured is configured by directly connecting the load/voltage converter and the acceleration/voltage converter, and the
Since the acceleration signal obtained from the voltage transducer is converted into a displacement signal by integrating it twice, it is no longer necessary to attach the indenter to an arm fixed on a surface plate as in the case of conventional indenters. No matter what state the car is in, the tensile rigidity of any part of the outer skin of the vehicle can be easily measured, reducing the time required to evaluate the quality of the outer skin, and expanding the range of parts to be evaluated.

[Brief explanation of drawings]

Figure 1 is a configuration diagram showing a conventional load displacement measuring device;
The figure is a load/displacement diagram showing an example of the results of measuring tension rigidity using the apparatus shown in Fig. 1. Fig. 6 is a block diagram showing an embodiment of the present invention.
6 shows a structure showing a specific example of the indenter shown in FIG. 6. FIG. 2 is a diagram showing the results of measurement using the same XY recorder. 6...Load/voltage converter 8...Door panel 8a
...Outer panel 11...Indenter 12...Acceleration/voltage converter 14.15...Preamplifier 16...Amplification circuit 17
...Comparator 18...Load setting circuit 19.
...Output control circuit 20...Arithmetic circuit♀
♀ Around 0; Elbow 111x

Claims (1)

[Claims] 1. In a load-displacement measuring device that deforms a measurement point by pressing an indenter against an object to be measured, the relationship between the load and displacement is converted into an electrical signal and recorded, and the indenter is
A load/voltage converter that outputs an electrical signal according to the load,
It is configured by directly connecting an acceleration/voltage converter that outputs an electric signal according to the deformation acceleration of the measurement point, and integrates the acceleration signal output from the acceleration/voltage converter twice and converts it into a displacement signal. A load displacement measuring device characterized by being equipped with an arithmetic circuit.