JP2690626B2 - Maybe force detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-component force detector capable of detecting up to 6 component forces with a single body.

[0002]

2. Description of the Related Art In this type of multi-component force detector, a force F _X. F _Y. F _Z and the torque (moment) M _X.
M _Y. Measure M _Z. Normally, four beams are symmetrically passed between the two flanges around the axis of this flange,
The deformation (bending strain, shear strain) of this beam is measured with a strain gauge, and the component force F _X. F _Y. F _Z. M _X. M _Y. M
_Z is being measured. There are probably a wide variety of force detectors. All of them are selected according to the situation of the measurement target. For example, an extremely large number of multi-component force detectors have been proposed that can measure each component component (force and torque) of the same type of multi-component force with almost the same accuracy (for example, Japanese Patent Laid-Open No. 63-63).
-255635 gazette). Further, there is a multi-component force detector or the like that can measure only a specific component force instead of 6 component force, and can measure only a total component force, for example. In addition, one of the components of the applied force is, for example, M _Z is very large, and it is necessary to increase the strength of the detector against this, and at the same time, the measurement accuracy of the other weak component components is increased. Sometimes you want to measure with the same relative accuracy as. As such a multi-component force detector, the present applicant has already proposed in Japanese Patent Application Laid-Open No. 57-118132 a multi-component force detector suitable for measuring a moment applied to an axle of a moving vehicle. On the contrary, the applicant of the present invention has proposed a force detector suitable for the case where a relatively small torque is applied around the z-axis.
It is presented in the official gazette. However, since this multi-component force detector is attached to the beam and the strain gauge is only near the one flange, it is affected by the deformation of the flange, and the component force detected is affected by another component force, the so-called interference effect. Is recognized,
The measurement accuracy was not sufficient.

[0003]

The object of the present invention is to analyze the component forces in three directions to be measured in the Cartesian coordinate system, that is, X, Y, Z.
The directional force and moment have a significant directional anisotropy in the rated load and resolution. Especially, the rated load and resolution of the moment (torque) applied around the Z-axis are extremely small, and other than the component force to be measured. An object of the present invention is to provide a multi-component force detector capable of significantly reducing the influence of the component force of, that is, the interference effect.

[0004]

According to the present invention, the above-mentioned problem is solved by a measuring flange 1 to which a component force to be detected is applied, and a fixing flange 2 facing the measuring flange 1 in parallel.
It has four flat plate beams 3, 4, 5 and 6 having a rectangular cross section fixedly connected to the flange surfaces of both flanges 1 and 2 vertically, and the centers of both flanges 1 and 2 are perpendicular to the flange surfaces. Introducing a Cartesian coordinate system X, Y, Z with the Z-axis as the axis passing through and the origin being the intersection of the Z-axis with the intermediate plane extending in parallel between both flanges 1 and 2, and introducing a pair of flat plates. The beams 3 and 5 are arranged symmetrically with respect to the YZ plane while the short sides of the rectangular cross section are opposed to the ZX plane at regular intervals, and the other pair of flat plate beams 4 and 6 are short with the rectangular cross section. The sides of the flat plate beam are arranged symmetrically with respect to the ZX plane while being opposed to the YZ plane at regular intervals. A strain gauge (c, re, e) pasted in the vicinity
Strain gauges (d, o, chi) attached near the fixed flange 2 as a group B, and strain gauges (a, n, f) attached on the positive side near Z = 0 as a group C And the strain gauges (B, L, G) attached to the negative side are group D, and the strain gauges (T, L) attached to the long side face belong to groups C and D and are Z. Paste in the direction perpendicular to the axis, and all the remaining strain gauges (a, b, c, d, h, f, c
A) in the direction of the Z-axis, and force F _X. A bridge circuit for F _{Y is} provided with two flat plate beams 4, 6;
Strain gauges 4-A, 4-D, 6-H, 6-D of A group and B group attached to the outer short side surface of
D, 5-C, and 5-D, the rotational moment M _X. M
Bridge groups for _Y are attached to the outer short side surfaces of the two flat plate beams 3, 5;
Group of 4 strain gauges 3-a, 5-a, 5-b, 3-b;
4-a, 6-a, 6-b, and 4-b, and a bridge circuit for the force F _{Z is} provided with 16 pieces of C groups and D groups of the long side surfaces of all flat plate beams Strain gauge 3-f, 3
-Nu, 5-he, 5-nu, 3-to, 3-l, 5-to, 5-
Le, 4-to, 4-nu, 6-to, 6-nu, 4-he, 4-
16-strain gauge 3-ch of the long side surfaces of all the flat plate beams 3, 4, 5 and 6 and the strain gauge 3-ch. Three
-Li, 5-chi, 5-li, 3-ho, 3-o, 5-ho, 5-
Oh, 4-ho, 4-o, 6-ho, 6-o, 4-chi, 4-
This is solved by a multi-component force detector that can measure 6-component force, which is formed by 6-, 6-, and 6-re. Further, according to the present invention, the above-mentioned problem is solved by the present invention, wherein the pair of flat plate beams 3; 5 of the above-mentioned multiple force detector are arranged in parallel with each other by an odd number of flat plate beams 3 _1, 3 _2, 3 _2. 3 ₃ ; 5
_1, 5 _2. 5 ₃ replaced by, 'Yes is affixed to the flat beam 3 ^_2, 5 ₂ in the center strain gauge β long side surface' strain gauges α of the short side surfaces, two flat beam of gamma 'is the outermost 3 _{1 ，}
It is solved by being attached to the corresponding long side surface of 3 ₃ ; 5 _1, 5 ₃ . Further, according to the present invention, the above-mentioned problem is that the above-mentioned one pair of flat plate beams 3: 5 of the above-mentioned multi-component force detector are arranged in parallel with each other by an even number of flat plate beams 3 _1, 3 ₂ ; 5 _1, 5 ₂ , and the flat plate beam 3 having two short side strain gauges 3 _1. 3 ₂ ;
5 _1, 5 ₂ of strain gauges alpha 'pasted to the short side face' were equivalent to those connected in parallel, strain gauges β of the long side surfaces ', gamma' of two flat beam 3 _1. 3 ₂ ; 5 _1. Has been solved by the 5 ₂ corresponding are stuck on a long side surface.

Other advantageous configurations are described in the dependent claims.

[0006]

[Operation] As described above, the multi-component force detector according to the present invention uses the vertically long beam arrangement as proposed in Japanese Utility Model Laid-Open No. 48-55871. (Here, "longitudinal" means that the beam has a rectangular cross section, and the long side of the beam is parallel to a straight line extending from the central axis of the flange to the beam. 57-11
"Landwise" as in the beam arrangement of the multi-component force detector of Japanese Patent No. 8132 means that the beam has a rectangular cross section and the long side of the beam is perpendicular to a straight line extending from the central axis of the flange toward the beam. Say). In the arrangement such a vertically long beam structure, when M _Z load is small, because the bending strain of the beam is greater than the shear strain, output almost does not occur in shear stress. The contribution of M _{Z to} the detection is mostly due to bending stress. Further, in the multi-component force detector of the present invention, the load of M _Z is relatively small and the deformation of the flange is small, so that the performance is not deteriorated. Especially, the arrangement of the strain gauge attached to the beam is symmetrical with respect to the center of the beam, that is, the strain gauges attached to both ends of the flange are connected in a symmetrical bridge, and the strain gauge attached to the center of the beam is connected in a bridge. , Component force extraction into a single component is effectively performed.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The contents of the present invention will be specifically described below with reference to the accompanying drawings showing embodiments.

In a first embodiment of the invention, the main beam is 4
It will be described as a book. FIG. 1a shows a side view of a multi-component force detector according to a first embodiment of the present invention, and FIG.
A cross-sectional view of the line segment c-c is shown.

Here, 1 is a measurement side flange, 2 is a fixed side flange, and these flanges 1 and 2 are four at a distance L and are arranged symmetrically with respect to an axis (Z axis). The main beams (hereinafter simply referred to as beams) 3 to 6 are connected and fixed to each other. In this case, the cross-sections of these beams are rectangular, as shown in FIG. 1b, with the long sides B ₁ and the short sides T ₂ for the beams 3, 5 and the beams 4, 6 respectively. On the other hand, the long side is B ₂ and the short side is T ₁ , and the intervals between the two opposing beams 3 and 5 and 4 and 6 are L ₁ and L ₂ , respectively.

In the multi-component force detector having the above structure, the beam
X axis from 4 to beam 6, beam 3 from beam
Take the Y-axis in the direction of the frame 5 and measure side flange 1 to the fixed side.
The Z axis is taken in the direction of the flange 2. And each axis X, Y,
The component force in the Z direction is F _x,F_y,F_zAnd each axis X,
The rotational moments around Y and Z are M_x,M_y,M _z
And

When a component force F _y acts on the measuring side flange 1, the beams 3 and 5 are deformed as shown in FIG. 2a, and the beams 4 and 6 are deformed as shown in FIG. 2b. And each beam 3
The forces transmitted to 6 are proportionally divided in proportion to the spring constant with respect to the beam component force F _y .

[0012] Now, for simplicity of _{description, B 1 ≒ B 2, T} 1 when ≒ T _2, and _{L 1 ≒ L 2, B 1} »T 1, anti-beam 4,6 regard component force F _y Power can be ignored. The stress distribution generated by the component force F _y is shown in FIG.

FIG. 3b shows the stress distribution occurring at cross section 7-8, and FIG. 3c shows the stress distribution occurring at surface 7-9. As can be seen from these figures, the maximum bending stress due to the component force F _y occurs at the roots 7, 8, 9, 10 of the beam. Therefore, if the strain gauge is attached as close as possible to the base, the component force F _y can be detected efficiently.

With respect to the component force F _x , the same idea can be applied only by replacing the beams 3 and 5 in the case of the component force F _y with the beams 4 and 6 due to its symmetry.

Next, as shown in FIG. 4, the measuring flange 1
When a rotational moment M _x is applied to the beams 3 to 6, bending stress occurs in the beams 3 to 6 as shown in FIG. 4b. That is, the maximum bending stress σ _max occurs on the outer end faces 11-12, 13-14 of the beams 3, 5 in the Y-axis direction with respect to the rotation moment M _x . Therefore, the rotational moment M _x can be detected as the bending stress by attaching the strain gauges to the outer ends of the beams 3 and 5 at the same positions on the cross section perpendicular to the Z axis.

With respect to the rotation moment M _y , the same idea is established only by replacing the beams 3 and 5 with the beams 4 and 6 in the case of the rotation moment M _x .

Next, consider the case where the rotational moment M _z acts. Ignoring the twist of the beam, the result is as shown in FIG. FIG. 5a shows how the four beams are bent by using only one beam as a representative. Also, FIG. 5b shows the stress distribution in the cross section 15-16 of the beam root. From this FIG. 5b, if a strain gauge is attached to the base of the antinode of the beam, the rotation moment M _z can be effectively detected.

Further, when the component force F _z acts, the same stress is simultaneously generated in the four beams 3 to 6. Therefore, the component force F _z can also be detected separately from the other component forces F _x, F _y, M _x, M _{y, and} M _z .

From the above explanation of the stress distribution, the six-component force F _x, F
It is possible to detect _y, F _z, M _x, M _{y, and} M _z independently without interfering with each other.

Next, with reference to the above-mentioned stress distribution, an explanation will be given of a specific example of an advantageous method for attaching a strain gauge and a bridge connection circuit for eliminating mutual interference of component forces by these strain gauges.

FIGS. 6a and 6b are a schematic side view and a cross-sectional view, respectively, showing the strain gauge attachment position in the first embodiment of the present invention. Here, strain gauges that play the same role due to the Z-axis symmetry of the beams 3 to 6 are given the same reference symbols a to o,
Group as shown. That is, two strain gauges, preferably adjacent to each other, located at the center of the beam in the longitudinal direction on the short side of the beam cross section are marked with symbols a and b, and those affixed to the bases of both flanges 1 and 2 are labeled with c respectively. Turn it on. Also, two strain gauges, preferably adjacent to each other, located at the center in the longitudinal direction of the beam on one of the long sides of the beam cross section are marked with the reference signs F and G, respectively. And attach. In addition, reference numerals "n" and "r" are attached to the ones in the center of the beam in the longitudinal direction on the other long side, and reference numerals "e" and "e" are attached to those at the bases of the flanges 1 and 2. In this case, the strain gauges of the group corresponding to the codes F and N and the strain gauges of the group corresponding to the codes T and L are attached in the direction orthogonal to the Z axis, and all strains other than this one group are attached. The gauge is attached parallel to the Z axis.

Hereinafter, for convenience of explanation, it is assumed that the strain gauges of the groups corresponding to the symbols G and L are attached in the direction orthogonal to the Z axis.

7a to 7f, the component forces F _x, F _y, F _z, M _x, respectively formed by combining the strain gauges defined above are shown.
The connections of the bridge circuit for detecting M _{y and} M _z are shown.
Here, the positions of all the strain gauges are indicated by designating beams by reference numerals 4 to 6 and positions in the beam by reference numerals a to o.

FIG. 8 and FIG. 9 show the output of the bridge circuit for each component force and the output of the strain gauge alone used at that time. Here, + of the output indicates increase in resistance, − indicates decrease in resistance, and 0 indicates no change in resistance. The symbol A ~
M is the resistance change of each strain gauge that is not directly output to the bridge output end. Further, the symbol 1 indicates that there is a change in the bridge output, and 0 indicates that there is no change in the bridge output.

When the component force F _x acts, the stress shown in FIG. 3c is generated in the beams 3 and 5 of the F _z detecting gauge. Since the gauge is not in the center of the beam, the output of A is generated at the gauge and the output of B is generated at the gauge. However, at the output terminals of the F _z bridge, their outputs cancel each other out, so that no output change occurs. Further, Gejii beams 4,6, the resistance change of ± C occurs in Russia, M _x, the output change in the same way to the output terminal of the M _y bridge does not occur. Further, the strain gauges at the positions of the beams 3 and 5 undergo a resistance change of ± D, but no output change occurs at the output end of the M _z bridge.

Even when the component force F _y is acting, the same thing occurs due to the symmetry, and therefore detailed description will not be given.

When the component force F _z acts, the strain gauges constituting the F _x bridge and the F _y bridge undergo the resistance change E due to the same stress, but at the output end of each bridge, the resistance change E is caused. The outputs are canceled out, and the output does not change. However, the strain gauges of He and N in the F _z bridge have a direct stress, and the gauges of G and Le have a resistance change F in the opposite direction due to the Poisson's ratio. These resistance changes give an output change at the output end.

When the component force M _x acts, the resistance changes of ± G occur in C and D of beams 3 and 5, and
The output of ± H is generated in Nu and Oh,
Outputs of ± J are generated for F, J, L, N, and O, and ± K are output for T and L, but no output is generated for bridges other than M _x .

When the component force M _y acts, it is the same as when the component force M _x acts.

When the component force M _z acts, the
An output of ± L is generated at the output, and an output of ± M is generated at the output and the output.
_No output occurs on bridges other than _z .

In the above-mentioned embodiment, the 6-component force detector is shown, but it can be realized as a multi-component force detector in which some component forces in the 6-component force are collected. Further, the combination arrangement of the strain gauges may be changed, or 3-to-le for detecting the F _z component force may be used.
Instead of the Poisson's ratio output gauges of G and R, it is free to use a strain gauge attached to a portion where no strain appears as a dummy.

Further, it is possible to use only the gauges of the beams 3 and 5 for detecting M _z or to construct only the gauges of the beams 4 and 6 as a bridge.

10 to 12 schematically show another detector according to the present invention. All of these three types of detectors are configured by a plurality (two or three) of the pair of beams 3 and 5 shown in FIG. As for the sticking position of the strain gauge, the symbol α corresponds to a, b, c, and d in correspondence with FIG.
The symbol β corresponds to li, n, le, and o, and the symbol γ corresponds to e, h, to, and chi. Since the bridge connections of these strain gauges are the same as those in FIG. 7, further description will be omitted.

Using the rosette gauges, the strain gauges at the fist and le positions described with reference to FIGS. 6a and 6b and the strain gauges at the to and n positions attached adjacent to these strain gauges are
It can also be attached to the center of the beam.

As described above, various embodiments of the present invention can be constructed. It goes without saying that these configurations are within the scope of the present invention as long as they are the configurations defined in the claims.

[0036]

The advantage obtained by the multi-component force detector according to the present invention is that even if the structure is relatively simple, a small torque z
Suitable for measurement when applied around the axis, the detected component force does not show the influence of other component forces, so-called interference effect, and guarantees the same relative measurement accuracy for each component force, high precision Can measure component force with good reproducibility.

[Brief description of the drawings]

FIG. 1 is a side view (a) of a multi-component force detector of a first embodiment according to the present invention and a cross-sectional view (b) taken along line cc.

2 is a side view schematically showing the deformation (a) of the beams 3 and 5 and the deformation (b) of the beams 4 and 6 when a component force F _x acts on the detector of FIG. 1. FIG.

FIG. 3 is a side view (a) showing local positions of beams 3 and 5 when a component force F _y is applied to the detector of FIG. 1, a schematic stress distribution diagram (b) and a surface 7 occurring in a cross section 7-8. It is a model stress distribution diagram (c) which arises in -9.

FIG. 4 is a schematic stress distribution diagram corresponding to a side view (a) showing local positions of the beams 3 and 5 when a component force M _y acts on the detector of FIG. 1.

FIG. 5 is a side view (a) and corresponding stress distribution diagram (b) showing the deformation of the beam (only one is shown due to symmetry) when a rotational moment M _z is applied.

FIG. 6 is a side view (a) and a cross-sectional view (b) showing an attachment position of a strain gauge.

FIG. 7 is a connection diagram (a to f) of a bridge circuit for detecting each component force.

FIG. 8 is a diagram showing an output of a bridge circuit corresponding to each component force.

9 is a diagram showing the output of the bridge circuit corresponding to each component force, and is a division diagram of FIG. 8.

FIG. 10 is a schematic sectional view showing a beam arrangement of a second embodiment.

FIG. 11 is a schematic cross-sectional view showing the beam arrangement of the third embodiment.

FIG. 12 is a schematic cross-sectional view showing the beam arrangement of the fourth embodiment.

[Explanation of symbols]

1 measuring flange 2 fixing flange 3-4 beam i ~ Oh strain gauge attaching position _{F x, F y, F z} , M x, M y, M z component force

Claims (5)

(57) [Claims] 1. A measuring flange (1) to which a component force to be detected is applied, a fixed flange (2) facing the measuring flange (1) in parallel, and perpendicular to the flange surfaces of both flanges (1, 2). And four flat plate beams (3, 4, 5, 6) having a fixedly connected rectangular cross section, and an axis line passing through the centers of the flanges (1, 2) perpendicular to the flange surface is the Z axis, An orthogonal coordinate system X, Y, Z having an origin at the intersection of the Z axis and an intermediate plane extending in parallel with both flanges (1, 2) is introduced, and one pair of flat plate beams (3, 5 ) Are arranged such that the short sides of the rectangular cross section are opposed to the ZX plane at regular intervals and are symmetrically arranged with respect to the YZ plane, and the other pair of flat plate beams (4, 6) are the short sides of the rectangular cross section, respectively. Are opposed to the YZ plane at a constant interval and to the ZX plane. Strain gauges (C, R, E) attached in the vicinity of the measurement flange (1) on the three sides of each plate beam excluding the Z-axis side short side face are group A. , Strain gauges (d, o, and chi) attached near the fixed flange (2) are group B, and Z =
The strain gauges (a, n, f) attached to the positive side near 0 are group C, and the strain gauges (b, le, g) attached to the negative side are group D. Belong to the long side, one of the strain gauges (G, L) is attached in the direction perpendicular to the Z axis, and all the remaining strain gauges (A, B, C, D, H, F, Chile,
J, paste e) in the direction of the Z-axis, the force Fx, two respective flat beam bridge circuit for F _Y (4,6; A group and B group was attached to the outer short side surface of the 3, 5) 4 strain gauges (4-C, 4-D, 6
-C, 6-D; 3-C, 3-D, 5-C, 5-D), and the rotational moment _MX. Two respective flat beam bridge circuit for M _Y; 4 sheets of strain gauge C group and D group pasted on the outer short side surface of the (3,5 4,6) (3-
A, 5-a, 5-b, 3-b; 4-a, 6-a, 6-
B, 4-b), and a bridge circuit for the force F _{z is applied} to all plate beams (3,
4, 5 and 6) 16 groups of strain gauges (3-he, 3-nu, 5-he, 5-nu, 3-to, 3-
Le, 5-to, 5-le, 4-to, 4-nu, 6-to, 6-
(4), (4), (4), (4), (6), (6), and (6), and a bridge circuit for the rotation moment Mz is formed on all the long side surfaces of the flat plate beams (3, 4, 5, 6). 16 strain gauges of group B (3-chi, 3-ri, 5-chi, 5-ri,
3-ho, 3-o, 5-ho, 5-o, 4-ho, 4-o, 6
A multi-component force detector capable of measuring 6-component force, characterized in that it is formed of (e, 6-o, 4-chi, 4-li, 6-chi, 6-li). 2. A method according to claim 1 of the one pair of flat beam (3; 5) with each other respectively parallel three or more odd number of flat beam _{(3 1.3 2.3 3; 5 1.5 2 .} 5 ₃ )
In replacement, strain gauge narrow side (alpha ') is the center of the flat beam is affixed to (3 _{2.5 2),} the strain gauge of the long side surface (beta', gamma ') of the outermost two Flat beam (3 _1.
3 ₃ ; 5 _1. 5. The force detector according to claim 1, wherein the force detector is attached to the corresponding long side face of 5 ₃ ). 3. Replacing said one pair of flat plate beams (3; 5) of claim 1 with two or more even flat plate beams (3 _1. 3 ₂ ; 5 _1. 5 ₂ ) parallel to each other. , A plate beam with two short side strain gauges (3 _1. 3 ₂ ; 5
_1. 5 ₂ ) is equivalent to a parallel connection of strain gauges (α ″) attached to the short side surface, and strain gauges (β ′,
γ ′) has two flat plate beams (3 _1. 3 ₂ ; 5 _1. 5 ₂ )
The multi-component force detector according to claim 1, wherein the multi-component force detector is attached to the corresponding long side surface of the. 4. Any of two sets of adjacent strain gauges of group C and group D, which are attached to both long side surfaces of the flat beam (3, 4, 5, 6). The multi-component force detector according to any one of claims 1 to 3, further comprising one rosette strain gauge and affixing it at a position of Z = 0. 5. The 6 defined in any one of claims 1 to 4.
In the component force detector, the component force F _X. F _Y. F _Z. M _X, M
A multi-component force detector characterized by forming a bridge circuit for only a necessary component force of _{Y and} M _Z and measuring only the component force.