JPS6141934A - Force transducer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a force transducer, in particular for a gravimetric cell, comprising a cylindrical compression member, for applying a force to be detected to an end face of the compression member, the compression member being It has groove-shaped blind holes extending in the longitudinal direction of the force direction and arranged opposite to each other, the bottoms of the blind holes constitute a bridge part, and the longitudinal direction of the force direction and the force The present invention relates to a force transducer having a strain gauge extending transversely to the direction of the force transducer.

German Utility Model No. 80 30 920 discloses such a force transducer, the sensitivity of which increases the depth or width of a slotted blind hole in a compression member. It can be increased depending on the situation. However, in known force transducers, if the predetermined values for the sensitivity and measurement range of the force transducer are exceeded due to excessive removal of material of the compression member during the formation of the blind channel by milling,
It is not possible to reduce the sensitivity of the force transducer again and thus extend its linearity measurement range.

SUMMARY OF THE INVENTION An object of the present invention is to provide a transducer user whose sensitivity and therefore its linearity measurement range can be precisely adjusted to a predetermined value.

In order to achieve this object, the Katrance Gysa according to the present invention is characterized in that the bridge portion has through holes disposed before and after the strain gauge in the direction of force.

In the present invention, the sensitivity of the force transducer can be increased not only by increasing the depth or width of the channel blind holes, but also by increasing the diameter of the through holes and decreasing the distance between the through holes. The sensitivity and therefore the linearity measurement range of the force transducer can also be adjusted very precisely to a predetermined value.

The invention will now be described in detail with reference to the drawings.

FIG. 1 is a side view showing a part of a cylindrical compression member 1 in cross section, and the end faces 2 and 3 of this compression member are connected to the force 4 to be detected.
It operates according to The compression member 1 has slotted blind holes 5 and 6 extending in the longitudinal direction of the force, which are shown partially in section in FIG. The bottom surfaces 7 and 8 of the groove-shaped blind holes 5 and 6 constitute a bridge 9, on which strain gauges 10 to 10 extending in the longitudinal direction and transverse to the direction of force are arranged. 13 will be provided. In order to reduce the sensitivity of the force transducer, the bridge section 9 is provided with through holes 14 and 15 before and after the strain gauges 10-13 in the direction of the force.

Figure 2 shows the compression member 1 of Figure 1 around its long axis.
A state in which the groove-shaped blind hole 5, strain gauges 10 and 11, and through holes 14 and 15 are made visible by rotation is shown.

The thickness b of the bridging portion 9 is determined by the depth of the groove-shaped blind holes 5 and 6 arranged oppositely. The deformability of the compression member 1 and therefore the sensitivity of the force transducer is therefore determined by the blind slot 5 in the compression member.
and 6 are arranged, and thus the smaller the dimension of this thickness b, the larger it becomes. The sensitivity of the force transducer can also be increased by increasing the width a of the blind grooves 5 and 6. Due to excessive removal of material, the width or depth of the blind slots 5 and 6 has become too large;
If the deformability of the compression member 1 becomes excessive in the area of the strain gauges 10 to 13, the deformability of the compression member 1 in the area of the strain gauges 10 and 13 is reduced by providing through holes 14 and 15. The sensitivity of the force transducer can also be reduced. Therefore, the deformability of the strain gauges 10 and 12 in this area decreases as the diameters of the through holes 14 and 15 increase and as their relative distance decreases. The sensitivity of the force transducer can also be reduced by providing a blind hole in the bridge 9.

If the through holes 14 and 15 are not provided, when the force 4 is applied, the strain gauges 10 and 12 extending in the longitudinal direction of the force direction are shortened and extend in a direction transverse to the force direction. The compression member 1 is deformed in a state where the strain gauges 11 and 13 are expanded.

When the compression member 1 is provided with through holes 14 and 15, when the force 4 is applied to the compression member, the lines of force are formed in the through holes 14 and 15.
It concentrates on the portion of the bridge portion 9 remaining on one side of the area.

Therefore, the larger the diameters of the through holes 14 and 15 and the smaller the distance of the through holes from the strain gauge, the more uneven the distribution of the lines of force in the center of the compression member l, i.e. the lines of force are also compressed. It is more strongly concentrated in the area on one side of the strain gauges 10 to 13 in the member 1. However, the fewer the number of lines of force extending through the area of the bridging part 9 existing between the strain gauges 10 to 13, the smaller the extent to which this area is deformed when the force 4 is applied; Therefore, strain gauge 1
The range in which 0 to 13 are transformed becomes smaller. As a result, the sensitivity of the force transducer is reduced and the measurement range with linear properties is increased. Due to the excessive fiber density, the thickness b of the bridging portion 9 in the area of the strain gauges 10 to 13 is increased, so that the strain gauge 10 extends in the longitudinal direction in the direction of the force 4 when a force is applied. and 12 are stretched, the characteristics become non-linear.

The force transducer subjected to the test comprises a cylindrical compression member 1 with a diameter of 54 mm, which has slotted blind holes 5 and 6 with a length of 60 mm and a radius of 21 mm. These blind holes are
The compression member 1 is cut to an appropriate depth so that a bridge portion 9 having a thickness of 3 fl is obtained.

If the through holes 14 and 15 are not provided, the compression member l will have approximately 1
A load of up to 4 tons can be applied.

In contrast, the compression member 1 has a diameter of 61 m and a relative distance of 48 m.
If the through holes 14 and 15 are present, a load of up to about 15.5 tons can be applied to the compression member. The load capacity of the compression member is approximately 16.5 tons when the diameter of the through hole is 8.
When the diameter of the through hole is 10 m, it is approximately 1 st.

[Brief explanation of the drawing]

FIG. 1 is a side view showing a part of an embodiment of the present invention in cross section, and FIG. 2 is a side view obtained by rotating FIG. 1 by 90 degrees. 1... Cylindrical compression member 2.3... End surface 5.6.
... Blind hole 7, 8 ... Bottom surface 9 ... Bridge part
10-13...Strain gauge 14.15...
Through hole Fl(:i, I FIG, 2=199

Claims (1)

[Claims] 1. A force transducer, in particular for a gravimetric cell, comprising a cylindrical compression member (1), for applying a force to be detected on the end faces (2, 3) of said compression member, said compression member producing a force It has groove-shaped blind holes (5, 6) which extend in the longitudinal direction of the direction of In a force transducer, the bridge has strain gauges (10-13) extending in the longitudinal direction of the force direction and in a direction transverse to the force direction.
13) A force transducer characterized in that it has a configuration having through holes (14, 15) arranged before and after the force transducer.