JP3060259B2 - 3 component force meter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-component force meter, and more particularly, to an arbitrary point on an object when a rectangular coordinate system composed of three axes of X, Y, and Z axes is imagined. It relates to a three-component force meter that detects force as three independent component forces.

[0002]

2. Description of the Related Art Conventionally, a component meter for detecting a force used at one point of an object as a plurality of independent component forces is disclosed, for example, in Japanese Patent Application Laid-Open No. 2-176438. FIG. 11 is an external perspective view of the force gauge. In the drawing, reference numerals 30 and 30 denote horizontal beam-like horizontal beams which extend symmetrically in the horizontal direction and are flat in the vertical direction.
Fixed portions 31, 31 at the outer ends of 0, 30 are fixed to a support (not shown). A vertical beam 33 having a rectangular cross section is vertically provided on a thick portion 32 provided in the middle of the horizontal beams 30, 30.

In the above-described structure, the upper end surface of the vertical beam 33 becomes a load introducing portion 34, and the load introducing portion 34 has an X axis,
Loads are applied from three directions of the Y axis and the Z axis. That is, X
The load from the axial direction is applied to the opposing first plane 3 of the vertical beam 33.
It is detected by strain gauges 36, 36 attached symmetrically above and below 5a, 35b, respectively.

A load from the Y-axis direction is applied to the first plane 3
Second plane 37 orthogonal to 5a, 35b and facing each other
Detected by strain gauges 38, 38 attached symmetrically above and below a, 37b, respectively. The load from the Z-axis direction is applied to the strain gauges 39, 40 symmetrically attached to the center and outer ends of the front and back surfaces of the cross beams 30, 30, respectively.
Is detected by

[0005]

The conventional force gauge constructed as described above is used, for example, for measuring the contact pressure distribution of a tire when a car is running. A plurality of force transducers are incorporated in a ground contact plate, and forces from various directions are detected as a tire contact surface pressure distribution. In addition, by increasing the number of component force meters installed, more accurate measurement can be performed.

However, in the conventional force transducer, as described above, when the cross beam 30 for detecting the load in the Z-axis direction is formed into a beam, the vertical beam 33 for detecting the load in the X-axis and Y-axis directions is formed. On the other hand, it extends horizontally in the horizontal direction, and as a result, the size of the force gauge is increased, so that the number of installations is limited, and high-precision measurement becomes impossible.

Further, the above conventional force transducer has a problem that it is easily affected by a bending moment and an eccentric load. SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has as its object to reduce the size and simplify the configuration, and to prevent interference of forces acting from other directions. It is an object of the present invention to provide a highly accurate three-component force meter which is hardly affected by an unbalanced load and a bending moment.

[0008]

According to the present invention, in order to achieve the above object, when a rectangular coordinate system including three axes of an X axis, a Y axis, and a Z axis is imagined, an arbitrary point on an object is defined. In a three-component force meter that detects an acting force as three independent component forces, a load receiving portion having a large rigidity receiving portion formed at an upper portion and a large rigidity and a mounting flange portion to a supported body is formed at a lower portion. A portion is formed, connected between the force receiving portion and the load supporting portion, the lower half portion is formed with a quadrangular prism-shaped strain-generating portion having a smaller cross-sectional area than the upper half portion, the strain-generating column is formed, A first strain body having a through-hole formed through a central portion from the force receiving portion to the load supporting portion passing through the strain generating column;
A second rigid strain member having a rigid cylindrical portion attached to the upper portion of the force receiving portion, a diaphragm formed at the upper end of the cylindrical portion, and a force introducing portion formed at the center of the diaphragm. When the direction in which the force receiving portion and the load supporting portion are disposed is the Z axis of the rectangular coordinate system, the bending stress in the X-axis direction attached to one of the opposing surfaces of the strain generating portion is detected. An X-axis strain gauge that is attached to the other surface of the strain-generating portion that is orthogonal to the opposite surface and that detects a bending stress in the Y-axis direction; and a Z that is attached to the diaphragm and generated in the diaphragm. And a Z-axis strain gauge for detecting an axial stress.

[0009]

In the three-component force meter constructed as described above, of the forces applied to the force introducing portion, the component force in the X-axis direction is transmitted through the diaphragm and the cylindrical portion of the second strain body. The force is transmitted to the strain-generating portion via the force receiving portion of the first strain-generating body, and the bending portion generates a bending stress in the X-axis direction. The bending stress is detected by an X-axis strain gauge attached to the opposing surface of the strain generating part.

Further, the component force in the Y-axis direction is transmitted through the diaphragm and the cylindrical portion of the second strain generating element, transmitted to the strain generating section via the force receiving section of the first strain generating element, and is generated by the force. A bending stress in the Y-axis direction is generated in the distorted portion. The bending stress is detected by a Y-axis strain gauge attached to an opposing surface of the strain-generating portion orthogonal to the opposing surface.

The component force in the Z-axis direction deforms the diaphragm so as to bulge downward. The bending stress due to this deformation is detected by a Z-axis strain gauge attached to the diaphragm.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a front view of a three-component force meter according to the present invention, and FIG.
FIG. 3 is a cross-sectional view taken along line AA ′ of FIG. 1, and FIG.
Are longitudinal sectional views taken along line BB 'of FIG.

In each of the drawings, reference numeral 1 denotes a first strain body having a substantially columnar body as a whole. A short cylindrical force receiving portion 2 having a large thickness and high rigidity is provided at an upper portion, and a rigid portion having a large rigidity is provided at a lower portion. It has a load supporting portion 3 having a flange portion 4 for mounting to a non-supported member.

Between the force receiving portion 2 and the load supporting portion 3, a strain-generating column 5 in which a quadrangular prism-shaped strain-generating portion 6 whose lower half has a smaller cross-sectional area than the upper half is integrally formed. It is articulated.
In addition, a through hole 7 is provided which penetrates the center from the upper end of the force receiving portion 2 to the lower end of the load support portion 3 through the strain-flexing column 6.

Above the force receiving portion 2 of the first strain body 1, a cylindrical portion 8 having a large rigidity of the second strain body 9 is press-fitted and fixed by means such as welding. This cylindrical part 8
An elastically deformable thin-walled diaphragm 10 is integrally formed on the upper end surface.

A force introducing portion 11 having a constricted portion 11a is provided at the center of the upper surface of the diaphragm 10, and a force or a load W is applied to the force introducing portion 11.

Referring to FIG. 2, when the vertical direction in the drawing is the X axis, the horizontal direction in the drawing is the Y axis, and the direction perpendicular to the drawing is the Z axis, the load (force) W
It can be detected as component forces Fx, Fy, and Fz in the Y and Z directions. Among them, the component forces in the X-axis and Y-axis directions cause a bending stress in the strain generating portion 6, and the force in the Z-axis direction is , Causing tensile and compressive stresses on the surface of the diaphragm 10.

That is, the opposing X below the strain-generating portion 6
X-axis strain gauges 12a, 12b, 12c, and 12d for detecting bending stress in the X-axis direction are attached to the shaft surface by juxtaposing two gauge axes in a direction matching the Z-axis direction. .

Further, Y-axis strain gauges 13a, 13b and 13c, 13d for detecting a bending stress in the Y-axis direction on the opposed Y-axis surfaces below the strain-generating portion 6 have the same gauge axes as the Z-axis. Two sheets are attached side by side in the direction that matches the direction. Further, Z-axis strain gauges 14a, 14b, 14c, 14d for detecting a force in the Z-axis direction are attached to the back surface (bottom surface) of the diaphragm 10.

The Z-axis strain gauges 14a to 14d are:
As shown in FIG. 4, the diaphragm 10 is attached in a state where it is patterned so as to be biased toward the vicinity of the outer periphery and the vicinity of the center.
Of these, the strain gauges 14a and 14d are arranged on the surface near the outer periphery, and the strain gauges 14b and 14c
Are arranged on a surface near the inner circumference.

FIG. 5 is a longitudinal sectional view in which the component force meter according to the present invention configured as described above is incorporated in a component force detecting device. According to this, the flange portion 4 of the load supporting portion 3 is screwed into the female screw hole formed in the pedestal 16 with the bolt 15 inserted into the bolt hole 4a, and is fixed to the pedestal 16. The upper plate 1 is placed on a pedestal 16 so as to accommodate the body 5 and the cylindrical portion 8 of the diaphragm 10.
7 are combined. Force introduction part 1 of diaphragm 10
1, a force introducing plate 18 is supported by screw connection, and the upper surface of the force introducing plate 18 is arranged on the same plane as the upper surface of the upper plate 17.

On the other hand, X-axis strain gauges 12a to 12d and Y-axis strain gauge 13a attached to
Wiring code (gauge lead) 1 drawn from ~ 13d
9a is connected once to a terminal plate 20 attached to the flexure element 5, and a wiring cord (cable) 19b pulled out from the terminal plate 20 is passed through a wiring hole 3a penetrating the load support portion 3, and Drawn out from the wiring groove 16a.

The wiring cords 21 of the Z-axis strain gauges 14a to 14d attached to the diaphragm 10 are once connected to a wiring board 22 supported on the tubular portion 8, and the wiring cords 23 are strained from the wiring board 21. Through the through hole 7 penetrating through the column 5, it is drawn out from the wiring groove 16 a of the base 16 to the outside.

FIGS. 6 to 8 show bridge circuits for detecting the respective component forces in the X-axis, Y-axis, and Z-axis directions.
x, FIG. 7 shows a bridge circuit for detecting the component force Fy, and FIG. 8 shows a bridge circuit for detecting the component force Fz.

First, the configuration of each side of the bridge circuit of the component force Fx shown in FIG. 6 will be described. The first side 24 is the strain gauge 12a, the second side 25 is the strain gauge 12b, and the third side 26
Is the strain gauge 12c, and the fourth side 27 is the strain gauge 12
and 28a and 28b are input terminals of the bridge circuit, and 29a and 29b are output terminals of the bridge circuit.

Each side of the bridge circuit having the component force Fy shown in FIG. 7 is the same as above, and the first side is the strain gauge 13a,
The second side is the strain gauge 13b, and the third side is the strain gauge 1
3c, the fourth side is constituted by a strain gauge 13d.

Further, each side of the bridge circuit for detecting the component force Fz shown in FIG. 8 has a first side as a strain gauge 14a, a second side as a strain gauge 14b, and a third side as a strain gauge 14b.
c, the fourth side is constituted by a strain gauge 14d.

Next, together with the operation of the embodiment in which the present invention is applied to the component force detecting device configured as shown in FIG.
The operation of each bridge circuit that detects x, Fy, and Fz as electric signals will be described.

When a component force Fx acts on the force introducing plate 18 in the direction indicated by the arrow in FIG.
The resistance values of the strain gauges 12a and 12c decrease due to the compression of the strain generating portion 6 due to the bending stress.
2d receives a tensile stress due to the bending stress on the surface of the strain generating portion 6, and the resistance value increases.

Referring now to the bridge circuit of the component force Fx in FIG. 6, the resistance value of the strain gauge 12a on the first side decreases, the strain gauge 12b on the second side increases, and the strain gauge 12c on the third side. Decreases, and the strain gauge 12d on the fourth side increases. As a result, if the input terminal 28 is on the positive side, one output terminal 29a is connected to the other output terminal 29a.
The potential becomes lower than b, the output becomes + e, and the component force Fx is detected.

Next, when a component force Fy acts on the force introducing plate 18 in the direction of the arrow in FIG.
c indicates that the resistance value is increased by the tensile stress of the surface of the strain generating portion 6 due to the bending stress.
3d, the resistance value decreases. As a result, in the bridge circuit with the component force Fy of FIG. 7, the resistance values of the first side and the third side increase, and the resistance values of the second side and the fourth side decrease. It will be.

On the other hand, when a component force Fz acts on the force introducing plate 18, as shown in FIG.
The resistance value of c decreases due to compression, and conversely, the resistance value increases due to the tensile stress applied to the Z-axis strain gauges 14b and 14d.

As a result, in the bridge circuit for detecting the component force Fz shown in FIG. 8, the resistance values of the first and third sides decrease, and the resistance values of the second and fourth sides increase. An electric signal corresponding to the component force Fz is detected at the output terminal.

In the above description, three component forces Fx, F
Although the directions of the respective component forces are shown uniformly in order to make the operation by y and Fz easy to understand, actually, the component components Fx, Fy and Fz are combined on the force introduction plate 18. Or a bending moment.

For example, when a bending moment along the component force Fx direction or Fy direction is applied to the force introducing plate 18 and the diaphragm 10 is deformed as shown in FIG. 10, a bridge for detecting Fz in FIG. As can be seen from the circuit, the increase and decrease of the resistance value on each side cancel each other out, the equilibrium state is maintained, and the output becomes substantially zero. Therefore, the component force Fx or Fy
Only those are detected.

In the three-component force meter according to the present invention, the strain generating portion 6
Penetrating the through-hole 7 at the center, the sensitivity of the strain generating portion 6 to bending stress can be improved, and the mechanical strength and bending rigidity can be mechanically improved. Further, the through hole 7 can be effectively used as a wiring hole of the Z-axis strain gauge.

In the strain generating portion 6, the bending stress received from the upper portion can be obtained by biasing the strain gauge to the lower portion side since the lower portion side can obtain a stable stress value with respect to the upper portion portion. In addition, accurate and stable detection of bending stress can be performed.

The wiring cord of the strain gauge attached to the strain-generating portion 6 is once connected to the terminal plate 20 and
Since the lead-out wire is pulled out from 0, even if the external lead-out wire is strongly pulled, the strain gauge can be properly protected without peeling or damaging the strain gauge.

Further, since the detection of the stress in the Z-axis direction is performed by the diaphragm 10 close to the force application point, there is an effect that it is hardly affected by the bending moment and the unbalanced load.

Further, since the constricted portion 11a is formed in the force introducing portion 11, the uneven load and the bending moment can be absorbed by the constricted portion 11a, and the three-component force can be detected more accurately.

The present invention is not limited to the above-described embodiment, but can be variously modified without departing from the gist thereof.

For example, the strain-generating portion 6 is shown in the case where the cross-sectional shape is square, but it is cylindrical if the strain gauges on the X-axis side and the Y-axis side can be attached in the right angle direction. There may be. As the strain gauge of the diaphragm 10, a plurality (for example, four) of normal rectangular strain gauges other than those in the embodiment may be used.

[0043]

As described above, the three-component force meter according to the present invention comprises a strain-generating portion formed below a strain-generating column with component forces in the X-axis, Y-axis, and Z-axis directions; Because it was configured to detect by the diaphragm provided on the axis of
The size can be reduced, and the configuration becomes extremely simple.

Further, since miniaturization is realized and a large number of three-component force gauges can be arranged per unit area, it is possible to accurately detect a component force from various fields. In addition, it is possible to provide a highly accurate and highly reliable three-component force meter with almost no interference in each load direction.

[Brief description of the drawings]

FIG. 1 is a front view showing a configuration of a three-component force meter according to one embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along line AA ′ of FIG.

FIG. 3 is a longitudinal sectional view taken along line BB ′ of FIG. 2;

FIG. 4 is an enlarged plan view schematically showing a strain gauge attached to a diaphragm in FIG.

FIG. 5 is a longitudinal sectional view showing a state where the three-component force meter according to the present invention is incorporated in a component force detecting device.

FIG. 6 is a bridge circuit diagram for detecting a component force Fx.

FIG. 7 is a bridge circuit diagram for detecting a component force Fy.

FIG. 8 is a bridge circuit diagram for detecting a component force Fz.

FIG. 9 is a load deformation diagram of the diaphragm when a force acts on the diaphragm only in the Z-axis direction.

FIG. 10 is a modified view of the diaphragm when a bending moment acts on the diaphragm along the X-axis or Y-axis direction.

FIG. 11 is an external perspective view of a conventional beam-type force transducer.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 first flexure element 2 force receiving part 3 load support part 4 flange part 5 flexure column 6 flexure part 7 through hole 8 cylindrical part 9 second flexure element 10 diaphragm 11 force introduction part 11a constriction part 12a to 12d X-axis strain gauge 13a to 13d Y-axis strain gauge 14a to 14d Z-axis strain gauge 15 bolt 16 pedestal 16a wiring groove 17 upper plate 18 force introduction plate 19a, 19b wiring code 20 terminal plate 21, 23 wiring code 22 wiring board 28a, 28b Input terminal 29a, 29b Output terminal W Load Fx, Fy, Fz Component force

Continuation of the front page (56) References JP-A-2-176438 (JP, A) JP-A-63-96531 (JP, A) JP-A-2-75925 (JP, A) JP-A-2-163628 (JP) JP-A-53-81280 (JP, A) JP-A-58-138439 (JP, A) JP-A-64-41829 (JP, A) JP-A-2-73124 (JP, A) 63-15131 (JP, A) Japanese Utility Model Showa 48-10469 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) G01L 5/16

Claims (4)

(57) [Claims] 1. A three-component force meter that detects a force acting on an arbitrary point on an object as three independent component forces when a rectangular coordinate system including three axes of an X axis, a Y axis, and a Z axis is imagined. At
A force receiving portion having high rigidity is formed at an upper portion, and a load supporting portion having a large rigidity and a mounting flange portion to a supported body is formed at a lower portion, and is connected between the force receiving portion and the load supporting portion. The lower half portion is formed with a strain column having a square columnar strain portion having a smaller cross-sectional area than the upper half portion, and each of the force receiving portions reaches the load support portion through the inside of the strain portion. A first strain body having a through-hole penetrating a central portion thereof; a rigid cylindrical portion attached to an upper portion of the force receiving portion; and a diaphragm formed at an upper end side of the cylindrical portion. ,
A second strain body in which a force introducing portion is formed in the center of the diaphragm; An X-axis strain gauge attached to one opposing surface of the strained portion and detecting a bending stress in the X-axis direction; and an X-axis strain gauge attached to the other opposing surface of the strain-generating portion orthogonal to the opposing surface. A Y-axis strain gauge to be detected; and a Z-axis strain gauge attached to the diaphragm and detecting a stress in the Z-axis direction generated in the diaphragm.
Force transducer. 2. The three-component force meter according to claim 1, wherein the X-axis strain gauge and the Y-axis strain gauge are attached so as to be biased below the strain generating portion. 3. A wiring hole connected to a terminal of the X-axis strain gauge and a terminal of the Y-axis strain gauge, once connected to a terminal plate attached to the strain generating portion, and passed through the terminal plate to the load supporting portion. The three-component force meter according to claim 1 or 2, wherein the three-component force meter is configured to be drawn out to the outside. 4. The wiring of the Z-axis strain gauge is once connected to a terminal plate attached to the cylindrical portion of the second strain body, and is externally passed through a through hole penetrating through the first strain body through the terminal plate. 3. The three-component force meter according to claim 1, wherein the three-component force meter is configured to be pulled out.