JPH02309223A - Error adjusting method of load converter - Google Patents

Abstract

PURPOSE:To correct in a simple manner with high accuracy by cutting a part of a distorsion generating body corresponding to a measuring point in the circumference of a measuring reference point when an output value at said measuring point is different from a measuring value at said measuring reference point thereby to make correction of errors. CONSTITUTION:The relation between a reference load and an output value at a measuring reference point 11 which is preliminarily set among the free ends is determined. At the same time, the relation between the load and an output value at each of the other points in the circumference of the reference point 11, that is, eccentric load points 12a-12d is determined. When the output value at the eccentric load points 12a-12d is different from the measuring value at the reference point 11, a part of a distorsion generating body 1 is cut corresponding to the eccentric load point to correct errors. Therefore, the distorsion generating body 1 deforms minutely corresponding to a part thereof to which the load is applied, and the deformation of a distorsion sensor 4 becomes constant. Accordingly, errors can be corrected easily with high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for adjusting the error 7A of a load converter, which makes it possible to easily adjust the error iA.

(Prior art) To measure the amount of relatively heavy electrical load, a strain gauge is attached to the surface of a block-shaped strain body made of aluminum alloy, etc., and one end of this strain body is fixed. At the same time, a multilayer transducer is used that applies strain stress (deflection) to the strain gauge by applying a load to be measured to the other end, and thereby determines the amount of load from the change in electrical output generated by the strain gauge.

An example of this type of load transducer will be described with reference to FIGS. 3 and 4. First, in FIG. 3, reference numeral 1 denotes a strain-generating body, which has a rectangular shape, and one portion of which is fixed to a base plate 2, which is an immovable member, by a rivet 3. The other open portion of the flexure element 1 receives a load from the upper portion as indicated by the arrow. A strain gauge 4 is attached to the upper surface of the strain body 1. In this structure, when a load is applied to the strain body l in the direction of the arrow, the strain gauge 4 is also deformed (FQ) by the deformed strain body l, and the strain gauge 4 outputs an electrical output. will occur. Therefore, this output signal is processed to detect the load amount.

The one shown in FIG. 4 is a modification of the one shown in FIG. 3, and the one designated by the reference numeral 5.6 is a flexure element coupled to the flexure element l.

What is shown in FIG. 5 is an enlarged view of the strain gauge 4 used in the load transducer shown in FIGS. 3 and 4. In FIG. As shown in this figure, the strain gauge 4 is provided with four detection elements 8 at predetermined positions and intervals on a substrate 7, and these are connected by conductive wires 9 as shown in the sixth picture. connected to the bridge. The board 7 has 4 at one end.
Terminals 10 are provided, and are connected to the detection element 8 by conductive wires 9. As the strain gauge 4, it is possible to measure by using only 1lli without using the four detecting elements 8, but if four detecting elements 8 are used in this way and they are connected in a bridge connection. This reduces error factors, making it possible to obtain accurate measurement results.

(Problems to be Solved by the Invention) In the load converter shown in FIGS. 3 and 4 above,
Errors in the manufacturing dimensions of the flexure element 1, errors in the attachment position of the strain gauge, etc. become causes of errors in the measurement results. Figures 5 and 6
As shown in the figure, four detection elements 8 of the strain gauge 4 are used,
If these connections are made into bridge connections, the overall measurement results will be averaged, so the overall error will be small. Regarding the fact that the same result is obtained in
This problem has not been solved with plate-shaped strain bodies.

The present invention is a load converter made in view of this point.
- It is an error adjustment method.

(Means for Solving the Problems) As a means for solving the above problems, the present invention provides a strain gauge 4 affixed to the middle part of a plate-shaped strain body l whose one end is fixed and the other end is open. In a load transducer that receives a load at the free end of the flexure element l, the reference load amount at a predetermined measurement reference point 11 in the free end (other than the fixed part) and In addition to measuring the relationship between the output value and the load amount at other points located around the measurement reference point 11 (eccentric load point 12a = t2d), Load point +2a
When the output value at ~12d) is different from the measured value at the measurement reference point 11, depending on the different measurement point,
This is an error adjustment method in which the error is corrected by cutting off a part of the strain body l.

(Function) According to such an error adjustment method, the deformation state of the flexure element 1 changes slightly depending on the part of the flexure element 1 to which the load is applied, and the deformation (bending) of the strain gauge 4 in response to the load is constant. becomes. Therefore, once the adjustment is made, it is possible to always obtain a constant measurement result without strictly controlling the point at which the load is applied.

(Example) Hereinafter, the method of the present invention will be explained using figures. In FIGS. 1 and 2, reference numeral 1 denotes a strain-generating body, which is approximately rectangular and has a symmetrical shape with a narrow portion 1a formed in the middle portion. One of the parts is fixed to a base 2, which is an immovable member, with a rivet 3. The other open portion (free end) of the flexure element l receives a load as shown by the arrow from the upper portion of the upper plate 14 fixed with the rivet 3. A strain gauge 4 is attached to the upper surface of the narrow portion 1a.The center portion of the strain gauge 4 attached to the narrow portion 1a of the strain body 1 is defined as a measurement reference point 11. , 4 fl. eccentric load points 12a to +2d, which are the same distance away from the measurement reference point 11, are used as adjustment points.

In the method of the present invention, first, a reference load amount is applied to the measurement reference point 11. Then, the output value of the strain gauge 4 for this load = Jul is measured. This measured value should be memorized at the zero-order eccentric load point 12a~! Each point of 2d is also measured. This result is compared with the result for the measurement reference point 11 measured previously. As a result, there is no problem if the difference is within the allowable error range, but if it exceeds the allowable range, the narrow part 1a can be removed by cutting off a part of the narrow part 1a as follows. The deformation status of 1a is changed.

The shape of the load-receiving portion of the strain-generating body 1 is approximately square as described above, and the measurement reference point 11 at this central portion deforms the strain gauge 4 attached to the center of the narrow portion 1a (
The circumstances (giving the deflection) have a close relationship with the forces acting on the corresponding portions of the five narrow portions 1a also at the eccentric load points 12a to 12d. In other words, when a standard value load is applied to these eccentric load points, the output value of the strain gauge 4 at each point is larger than the output value for the measurement reference point 11, which means that the amount of deformation (bending) of the strain gauge 4 This can be seen as a lack of. As a result, this can be corrected by cutting off a predetermined portion of the narrow portion 1a.

From this point of view, when the measured value at the eccentric load point 12a is larger than the measurement result at the measurement reference point 11, the part indicated by the reference numeral 13a of the narrow portion 1a is removed. , for the eccentric load point +2b, the portion indicated by the symbol +3b is scraped off. Similarly below,
When the measured value at the eccentric load point becomes larger than the measurement result at the measurement reference point 11, the portion indicated by the related symbol is removed by an appropriate amount. As is clear from FIG. 1, good results can be obtained by scraping off the area from the side to the lower surface of the narrow portion 1a.

(Effects of the Invention) Since the present invention is an error adjustment method for a load converter configured as described above, one end is fixed.

In a load converter in which a strain gauge is attached to the middle part of a plate-shaped flexure element with the other end open, the load is received at the free end (other than the fixed part) of the flexure element. Errors caused by the load application site can be easily corrected with high accuracy. Therefore, highly accurate load measurement can be performed without using an expensive parallel plate structure load converter.

4 Brief Description of the Drawings Fig. 1 is a perspective view of a load transducer for explaining the method of the present invention, Fig. 2 is a plan view of the one shown in Fig. 1, and Fig. 3 is a perspective view showing a conventional load transducer. , FIG. 4 is a perspective view showing another conventional example, FIG. 5 is a plan view of a strain gauge with four detection elements, and FIG. 6 is a circuit showing the connection of the strain gauge shown in FIG. It is a diagram.

l - strain body 2...Foundation 4...Strain gauge 11-Measurement reference point 12a　N12d　-Eccentric load point 13a - 13d - Part to be scraped off 14-Top plate Figure 1 1... Strain body 2...Foundation 4...-long gauge １１　・・・　1llll fixed reference point 12a-12d... 1st chant weight point 13a-13d...part to create 14...Top plate Figure 2 Figure 3 Figure 4 Desert S map

Claims (1)

[Claims] (1) In a load converter, a strain gauge is attached to the middle part of a plate-shaped flexure element with one end fixed and the other end open, so that the load is received at the free end of the flexure element. Measures the relationship between the standard load amount and output value at a predetermined measurement reference point in the free end, and also measures the relationship between the load amount and output value at other points located around the measurement reference point. However, when the output value at the other point is different from the measurement value at the measurement reference point, depending on the different measurement point,
A method for adjusting an error in a load converter, characterized in that the error is corrected by cutting off a part of the strain body.