JPH0231812B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention separates each component of the force acting on the beam from the other components, and uses an electric strain gauge attached to the surface of the beam. This invention relates to a multi-force detector that electrically detects resistance changes.

[Conventional technology]

In recent years, with the rapid advancement of technology, ships, vehicles, aircraft, etc. have come to be used under extremely severe conditions. Therefore, in order to advance research and development regarding these vehicles, it is required to precisely measure what forces and moments actually act as external factors. Therefore, multi-force detectors have been used conventionally.

In this type of detector, a strain gauge is attached to the surface of a beam that elastically and fixedly connects a measurement side flange and a stationary side flange. The magnitude of the component force acting on the measuring flange is calculated from the strain generated in the beam.A bridge circuit formed by strain gauges emits an unbalanced output signal due to changes in the electrical resistance of the gauges, and this signal It takes advantage of the fact that the value is proportional to component force.

However, in order to separate the component of the external force in a predetermined direction from the other components and detect it with high precision with the above configuration, it is necessary to determine the location of the strain gauge, the shape, size, material, and placement position of each beam. Extremely strict conditions have been imposed, and it has been extremely difficult to suppress detection errors due to mutual interference between component forces without causing any practical problems.

[Purpose of the invention]

The object of the present invention is to eliminate the drawbacks of the prior art described above, to provide a strain gauge that has a simple structure, can reduce manufacturing costs, and produces accurate output without causing each force component to interfere with other force components. The object of the present invention is to provide a bridge circuit constructed by pasting and these strain gauges.

[Means to achieve the purpose]

The above object is achieved by the present invention, in which a fixed side flange, a measurement side flange opposite to this fixed side flange, and a fixed side flange are fixed parallel to the Z axis which is the center axis of both flanges, and one side is compared to the other side. have a sufficiently thin cross section, the wide side is parallel to the ZX plane, and form two pairs with the same spacing in this ZX plane,
Detects distortion in the axial direction of four flat beams whose narrow sides form two pairs with a distance from the ZY plane, and pairs of beams attached to the front and back surfaces of both ends of the beams. a first strain gauge group attached to the axial center of the beam to detect strain in the axial direction of the beam, and a second strain gauge group attached to the axial center of the beam to detect strain in the axial direction of the beam. It consists of a third strain gauge group that detects _strain in a direction inclined at 45 degrees to The bridge that detects the moment _M around the X axis and the Z formed by the third strain gauge group
This is achieved by a multi-force detector consisting of a bridge that detects the moment M _Z about the axis.

Another advantageous configuration is produced by fixedly connecting one of the two multi-force detectors with respect to the other with their axes common and mutually rotated by 90°, so that the 5-component forces F _x , F _y ,
It is possible to detect the five component forces of M _x , M _y , and M _z .

Another advantageous embodiment is that the second strain gauge group and the third strain gauge group are formed by rosette gauges.

〔Example〕

The present invention will be described in detail below with reference to the drawings showing embodiments.

As shown in Figure 1, the forces and _moments acting on any point 0 on an object are 6 in the X, Y, Z rectangular coordinate system: F _X , F _Y , _{F Z} , _M It can be separated into two independent forces and moments. In the following explanation, this symbol will be used.

FIGS. 2a and 2b schematically show the mechanical structure of the sensing section of the present invention. As shown in the figure, four flat beams 11 to 14 are fixedly connected between a fixed flange 2 and a measuring flange 1 that connects a component force measuring member (not shown). These beams 11 to 14 each have the same rectangular cross section with a thickness t much smaller than the width B. The thickness direction of these beams is oriented along the Y-axis, the width direction is oriented along the Y-axis, and the longitudinal direction of the beams is oriented parallel to the Z-axis. Beams 11 to 14 are
As shown in FIG. 2b, the flanges 1 and 2 are arranged in mirror symmetry with respect to the XZ plane and the YZ plane including the axial centers of the flanges 1 and 2, respectively. Therefore, the beam deformation is soft in the Y-axis direction and rigid in the X-axis direction.

3a, 3b and 3c all show examples of various gauge attachments for detecting force F _Y and moment M _X.

The strain gauges 111 to 126 are connected to each of the beams 11 described above.
~ 14 in pairs on both sides near both ends,
Moreover, it is attached in a direction that allows measurement of deformation strain in the Z-axis direction. These strain gauges 111-12
6 to the bridge shown in Figure 4 (hereinafter,
In the electrical circuit diagram, each strain gauge is represented by a resistor, and sections 3a-
The same reference numerals as in figure d) can be used to detect the gentle deformation of the beam, so only the component force F _Y can be measured with high sensitivity.

The wiring for a strain gauge that can only measure component force F _Y is as follows:
This can also be achieved with the bridge circuit shown in FIG. 5 or 6.

Furthermore, according to FIGS. 3b and 3c, the strain gauges 211 to 218 are arranged in pairs on both sides near the axial centers of the beams 11 to 14, and are oriented so as to measure the deformation strain in the Z-axis direction. It is pasted. As a bridge connection capable of measuring the moment M _X using these strain gauges 211 to 218, any one of the configurations shown in FIGS. 7, 8, and 9 can be used.

Next, near the axial center of the beams 11 to 14 mentioned above, as shown in FIG.
The strain gauges 211' to 218' are attached in pairs that are inclined at 45 degrees with respect to the vertical direction of the plates 211' to 218' and intersect with each other at 90 degrees on the front and back surfaces, respectively. Here, the strain gauge shown by the dotted line in FIG. 3d corresponds to the strain gauge attached to the back surface.

In the case of the configuration shown in Fig. 2, when a moment M _Z is applied around the measurement side flange Z axis, each beam 11
~14 produces bending strain and shear strain. At this time, since the rigidity in the X direction is overwhelmingly larger than the rigidity in the Y direction, the moment M _Z can be expressed as M _Z ≈F _Z xL _Y , as can be understood from Figure 2b. Here, L _Y is beam 11,
12 and the beams 13, 14. Therefore, by connecting the strain gauges 211' to 218' in the bridge arrangement shown in FIG. 10, FIG. 11, or FIG. 12, the moment _MZ can be taken out as the output signal of the bridge.

To measure M _X and M _Z simultaneously, each beam 11
The longitudinal strain gauges 211 to 216 and the 45° strain gauges 211' to 216' are glued side by side in the width direction at the center of the axial direction of the surface of 14 (not shown), and with respect to the former strain gauge. One of the bridges shown in FIGS. 7 to 9 is used for the latter strain gauge, and one of the bridges shown in FIGS. 10 to 12 is used for the latter strain gauge. Alternatively, strain gauges 211-2
If corresponding rosette gauges are used as the strain gauges 16 and 211' to 216', the mounting space can be saved. In addition to the above configuration, beam 1
Strain gauges 111-12 glued to both ends of 1-14
2 to form the bridge shown in Figs. 4 to 6, a three-component force detector can be formed that can measure F _Y , M _X , and M _Z in total.

Furthermore, two three-component force detectors shown in Figures 3a to 3d are prepared, and one detector is rotated 90 degrees around this axis with the center axis of the flange common to the other detector. When fixedly connected, a new single detector can be formed. That is, F _x , F _Y ,
A five-component force detector of M _X , M _Y , and M _Z can be formed.

〔Effect of the invention〕

As explained above, although the multi-force detector according to the present invention has a simple structure, it can extract independent force components without interfering with other force components, is inexpensive to manufacture, and is easy to use. To enable easy and highly accurate component force measurement.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an orthogonal coordinate system that defines force components.
Figures 2a and 2b are schematic diagrams showing the structure of a multi-force detector according to the present invention. 3rd a, 3b, 3c, 3d
Figure 1 is a schematic diagram showing the position of strain gauges attached to the beam. Figures 4-6, Strain gauge bridge configuration for measuring F _Y. Figures 7-9, Strain gauge bridge configuration for measuring _MX . 10th to 12th
Figure, Strain gauge bridge configuration for measuring _MZ . Reference symbols in the figure: 1...Measurement side flange, 2...
Fixed side flange, 11-14...Beam, 111
~126...Beam end strain gauge, 211~218
...Beam center strain gauge.

Claims (1)

[Scope of Claims] 1. A fixed side flange, and a measurement side flange opposite to this fixed side flange, fixed in parallel to the Z axis which is the center axis of both flanges, and one side is sufficiently large compared to the other side. A flat plate with a thin cross section, the wide side is parallel to the ZX plane and forms two pairs with the same spacing on the ZX plane, and the narrow side forms two pairs with the same spacing on the ZY plane. four beams, a first strain gauge group attached to the front and back sides of both ends of the beams in pairs for detecting strain in the beam's axial direction, and attached to the center of the beam in the axial direction. A second strain gauge group that detects strain in the axial direction of the beam, and a third strain gauge group that is attached to the axial center of the beam and detects strain in a direction tilted at 45 degrees with respect to the axial direction of the beam. A bridge that detects the force F _y in the Y direction formed by the first strain gauge group, a bridge that detects the moment M _X around the X axis formed by the second strain gauge group, and a bridge that detects the moment M A multi-force detector comprising: a bridge that detects the formed moment M _Z around the Z axis; 2. A fixed side flange, and a measuring side flange opposite to this fixed side flange, fixed in parallel to the Z axis which is the center axis of both flanges, and having one side having a sufficiently thinner cross section than the other side, Four flat beams whose wide sides are parallel to the ZX plane and form two pairs with the same spacing on the ZX plane, and whose narrow sides form two pairs with the same spacing on the ZY plane; A first strain gauge group for detecting the strain in the axial direction of the beam, which is pasted in pairs on the front and back surfaces of both ends of the beam, and a strain gauge in the axial direction of the beam, which is pasted at the center of the beam in the axial direction. It consists of a second strain gauge group that detects the strain, and a third strain gauge group that is attached to the axial center of the beam and detects strain in a direction tilted at 45 degrees with respect to the beam axis. A bridge that detects the force _F in the Y direction formed by the gauge group, a bridge that detects the moment M _X around the X axis formed by the second strain gauge group, and a bridge around the Z axis formed by the third strain gauge group F _x , F _{y , M} A multi-force detector characterized by detecting 5 component forces of M _y and M _z . 3. The multi-force detector according to claim 1 or 2, wherein the second strain gauge group and the third strain gauge group are comprised of rosette gauges.