JP2015094607A - Strain gauge and strain analysis system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a strain analysis system which is capable of analyzing a strain amount as well as a main axis direction of strain by using a strain gauge which is not affected by temperature variation in the main axis direction as well as in a horizontal axis direction.SOLUTION: The strain analysis system includes four strain gauges in total, including first and second main axis strain gauges (1 and 2) formed on a substrate 10 and connected to two opposite sides of an equivalent bridge circuit respectively and first and second horizontal axis strain gauges (3 and 4) respectively connected to two other sides adjacent to the two opposite sides. Four connection terminals (T1 to T4) connecting end points of respective strain gauges to each other are provided. The four strain gauges are of the same electric resistance value and the same resistance temperature coefficient. Therefore, when an ambient temperature is varied, variations in resistance value of the four strain gauges are equalized and are cancelled by each other. That is, an apparent strain output does not occur in the output of the equivalent bridge circuit.

Description

  The present invention relates to a strain gauge and a strain analysis system using the strain gauge, and more particularly to a strain gauge capable of performing stable strain measurement in an environment with a temperature change and a strain analysis system using the strain gauge. is there.

In general, when measuring strain using a strain gauge formed by attaching a strain sensitive resistor made of a Ni-Cr alloy or Cu-Ni alloy to the surface of the substrate, the substrate is measured on the surface of the object to be measured. In addition, a Wheatstone bridge circuit is configured using one, two, or four strain-sensitive resistors, and a strain output corresponding to a change in resistance value is detected by the Wheatstone bridge circuit.
Moreover, the resistance value of such a strain sensitive resistor varies with temperature. In other words, since it has a resistance temperature coefficient, it is necessary to perform predetermined temperature compensation. As the temperature compensation method, the following various compensation methods have been conventionally employed.
The first method is the “active dummy method” that is most often used. The circuit configuration is such that an active gauge and a dummy gauge are inserted into adjacent sides of the bridge, respectively. is there.
The second method is “Circuit Compensation Method Using Strain / Temperature Two Elements”. One gauge has two elements, one with strain and temperature, and the other with resistance mainly changing with temperature. These are connected to two adjacent sides of the bridge, respectively, and adjust the external resistance to cancel the temperature effect.

The third method is a thermocouple method often used for high-temperature strain measurement, which uses a DC power supply for the bridge and compensates the temperature by offsetting the output voltage due to the zero point movement of the strain gauge with the output of the thermocouple. is there.
The fourth method is a method using a temperature coefficient gauge combined with a temperature coefficient of resistance, in which two resistance elements having different resistance temperature coefficients are combined to form one gauge, Resistance and temperature coefficient are selected. As its configuration, when attached to a material to be measured, one element having a positive temperature coefficient in a predetermined temperature range and another element having a negative temperature coefficient are connected in series. It is made.
However, in a conventional strain and strain analysis system, measurement is performed by instrumenting uniaxial strain gauges at several locations in the estimated strain direction. Single-axis gauges include apparent strain due to temperature and changes over time due to drift, so that sufficient accuracy cannot be obtained for application to thermal stress analysis involving temperature changes. In addition, there are problems such as lower sensitivity in the principal axis direction than a 4-gauge strain gauge.

In addition, the active dummy method has problems such as the location of the strain sensing element and the temperature sensing element (dummy gauge or thermocouple) being distant from each other and the non-uniformity of the resistance material. ing. For this reason, “cancellation of the change in resistance value of the strain sensitive element due to temperature” could not be performed completely. Further, the active gauge and the dummy gauge are individually attached to the object to be measured, and are connected to each other. Therefore, a lot of work is required for measurement preparation.
In any of the above compensation methods, the temperature coefficient of electrical resistance of the strain sensitive element and the coefficient of various conditions such as physical constants of the constituent material to be measured must match. In order to match this, the material of the strain sensing element of the strain gauge itself must be matched to the linear expansion coefficient of the object to be measured, such as iron, stainless steel, steel, aluminum material, plastic material, concrete material, etc. Need to choose. In addition, a special heat treatment must be applied to the strain sensitive element so that a strain gauge dedicated to the material of a specific object to be measured must be obtained, which is difficult in terms of strain gauge manufacturing technology. Furthermore, the linear expansion coefficient of the object to be measured is not only directional, but also varies depending on the manufacturing history, and the measurement error cannot be made zero by completely eliminating the influence of temperature.

In order to deal with such problems, the present inventor previously proposed Japanese Patent Application Laid-Open No. 07-270109 (Patent Document 1).
The strain gage described in Patent Document 1 is connected to each of the first and second principal axis strain gauges connected to each of two opposing sides of the equivalent bridge circuit and each of the other two sides adjacent to the two sides. A strain gauge in which the connected strain gauges for adjusting the first and second equivalent circuit balances are integrally formed on the same substrate attached to the object to be measured, wherein the first and second spindle strains The electric resistance values of the gauge and the strain gauges for adjusting the first and second equivalent circuit balances are made equal and the resistance temperature coefficient is made equal, and each of the first and second spindle strain gauges is perceived. The axial directions are matched, and the shape of the strain gauges for adjusting the first and second equivalent circuit balances is such that the thermal strain output components in the direction perpendicular to the sensitive axis direction are equal. The strain gauges for adjusting the first and second equivalent circuit balances are formed into a rotationally symmetric rectangular spiral centered on the rotational symmetry axis, and are connected to two sides of the bridge circuit, respectively. The resistance values between the two end points of the strain gauges for adjusting the balance of the first and second equivalent circuits and the rotational symmetry center point are set equal.

JP 07-270109 A

However, in the strain gauge described in Patent Document 1, the first and second spindle strain gauges only detect strain in the spindle direction, and the first and second equivalent circuit balance adjustment strain gauges are strain detection. However, the shape of the strain gauge in the main axis direction and the strain gauge for equivalent circuit balance adjustment are greatly different. Therefore, there is a risk of drift occurring with time.
The present invention has been made in view of the above-mentioned circumstances, and a first object thereof is to surely cancel out a strain measurement error due to a change in temperature environment, and to consider the material of the object to be measured. The second object is to provide a strain gauge capable of increasing the strain sensitivity.
The third object of the present invention is to provide a strain analysis method capable of obtaining an unknown principal strain direction in an object to be measured with a predetermined accuracy and easily obtaining the maximum strain value in the principal strain direction. There is to do.

  In order to achieve the above-described object, the strain gauge according to the first aspect of the present invention includes first and second main spindle strain gauges connected to each of two opposing sides of the equivalent bridge circuit, A strain gauge integrally formed on the same substrate attached to an object to be measured, the first and second horizontal axis strain gauges connected to each of the other two sides adjacent to the two sides. When the four isosceles triangular regions are virtualized, the first and second principal axis strain gauges are arranged opposite to each other along the principal axis direction with the intersection of the diagonal lines as symmetry, and the principal axis direction Each of the isosceles triangles arranged opposite to each other is formed in the first and second main spindle grid parts having a triangular shape that is sequentially folded near the hypotenuse and the base and has a linear sensing part in the main axis direction. The first and second horizontal axis strain gauges are arranged opposite to each other along the horizontal axis direction orthogonal to the principal axis direction, with the intersection point being symmetric, and the hypotenuses of the isosceles triangles arranged opposite to each other in the horizontal axis direction And formed in triangular first and second horizontal grid portions that are sequentially folded in the vicinity of the base and have linear sensing portions in the horizontal axis direction, and one end of the first main spindle grid portion; A first connection terminal connected to a connection portion with one end of the second horizontal axis grid portion, a connection portion between the other end of the first main axis grid portion and one end of the first horizontal axis grid portion. A second connection terminal connected to the second connection terminal, a third connection terminal connected to a connection part between the other end of the first horizontal axis grid part and one end of the second main axis grid part, and the second Between the other end of the main axis grid portion and the other end of the second horizontal axis grid portion. A fourth connection terminal connected to the connection point, and equalizes the electric resistance values of the first and second main-axis strain gauges and the first and second horizontal-axis strain gauges and provides resistance. The temperature coefficient is equalized, and the grid in the main axis direction and the horizontal axis perpendicular to the main axis direction is perceived from the difference in linear expansion coefficient between the object to be measured and the strain gauge. It is characterized in that the two heat resistance output components of the combined resistance change are formed to be equal.

  In order to achieve the above-described object, the bridge gauge according to the second aspect of the present invention includes first and second main spindle strain gauges connected to each of two opposing sides of the equivalent bridge circuit, A strain gauge in which a first and a second horizontal axis strain gauge connected to each of two other sides adjacent to two sides are integrally formed on the same substrate attached to an object to be measured. Are divided by 90-degree dividing lines and imaginary four fan-shaped regions, the first and second main axis strain gauges are opposed to each other along the main axis direction with the intersection of the dividing lines as symmetry, The fan-shaped first and second spindle grid portions are folded back in the vicinity of the hypotenuse and arcuate portions of the sector that are opposed to each other in the principal axis direction and have linear sensing parts in the principal axis direction, Said And the second horizontal axis strain gauge is symmetrically arranged along the horizontal axis direction orthogonal to the main axis direction with the intersection of the dividing lines as symmetry, and the sector-shaped oblique sides arranged opposite to the horizontal axis direction and It is formed in fan-shaped first and second horizontal grid portions that are sequentially folded in the vicinity of the arc portion and have linear sensing portions in the horizontal axis direction, and one end of the first main spindle grid portion; A first connection terminal connected to a connection portion with one end of the second horizontal axis grid portion, a connection portion between the other end of the first main axis grid portion and one end of the first horizontal axis grid portion. A second connection terminal connected to the second connection terminal; a third connection terminal connected to a connection part between the other end of the first horizontal axis grid part; and one end of the second main axis grid part; 2 and the other end of the second horizontal axis grid part. A fourth connection terminal connected to the point, and the electric resistance values of the first and second main axis strain gauges and the first and second horizontal axis strain gauges are made uniform and the resistance temperature The coefficient is made uniform, and the grid in the main axis direction and the horizontal axis direction perpendicular to the main axis direction is generated from the resistance value coefficient caused by the change in resistance value and the temperature change caused by the difference in linear expansion coefficient between the measured object and the strain gauge. It is characterized in that the two heat resistance output components of the combined resistance value change are formed to be equal.

  In order to achieve the above-described object, a strain gauge according to a third aspect of the present invention includes first and second spindle strain gauges connected to each of two opposing sides of an equivalent bridge circuit, A strain gauge integrally formed on the same substrate attached to an object to be measured, the first and second horizontal axis strain gauges connected to each of the other two sides adjacent to the two sides. When the four isosceles triangular regions are virtually divided by diagonal lines, the first and second principal axis strain gauges are arranged opposite to each other along the horizontal axis direction orthogonal to the principal axis direction with the intersection of the diagonal lines as symmetry. Formed in the triangular first and second spindle grid portions that are sequentially folded in the vicinity of the two hypotenuses of the isosceles triangle disposed opposite to each other in the horizontal axis direction and have linear sensing portions in the principal axis direction. The first and second horizontal axis strain gauges are arranged opposite to each other along the principal axis direction with the intersection point being symmetrical, and in the vicinity of two oblique sides of an isosceles triangle arranged opposite to each other in the principal axis direction. It is formed in triangular first and second horizontal axis grid portions which are sequentially folded and have linear sensing parts in the horizontal axis direction, and one end of the first main axis grid portion and the second A first connection terminal connected to a connection portion with one end of the horizontal axis grid portion, and a connection portion between the other end of the first main axis grid portion and one end of the first horizontal axis grid portion. A second connection terminal; a third connection terminal connected to a connection portion between the other end of the first horizontal axis grid portion and one end of the second main axis grid portion; and the second main axis grid portion. Connected to the connection point between the other end of the grid and the other end of the second horizontal grid portion A fourth connecting terminal, and the electric resistance values of the first and second main axis strain gauges and the first and second horizontal axis strain gauges are made equal and the temperature coefficient of resistance is made equal. And the combination of the resistance value coefficient caused by the difference between the linear expansion coefficient between the object to be measured and the strain gauge and the resistance temperature coefficient caused by the temperature change. It is characterized in that it is formed so that the thermal strain output component of the resistance value change is uniform.

  In order to achieve the above-described object, the strain gauge according to the invention described in claim 4 includes first and second main-axis strain gauges connected to each of two opposing sides of the equivalent bridge circuit, A strain gauge in which a first and a second horizontal axis strain gauge connected to each of two other sides adjacent to two sides are integrally formed on the same substrate attached to an object to be measured. When the four sector regions are virtually divided by dividing lines at intervals of 90 degrees, the first and second main axis strain gauges are symmetrical in the horizontal axis direction orthogonal to the main axis direction with the intersection of the dividing lines as symmetry. The fan-shaped first and second spindle grid portions having a linear sensing portion in the main axis direction are sequentially folded in the vicinity of the respective hypotenuses of the fan shape arranged opposite to each other in the horizontal axis direction. Formed, The first and second horizontal axis strain gauges are arranged opposite to each other along the principal axis direction with the intersection point as symmetry, and are sequentially folded in the vicinity of the two hypotenuses of the sector shape arranged opposite to each other in the principal axis direction. It is formed in a triangular first and second horizontal axis grid part having a linear sensing part in the axial direction, and one end of the first main axis grid part and the second horizontal axis grid part A first connection terminal connected to a connection portion with one end, and a second connection terminal connected to a connection portion between the other end of the first main axis grid portion and one end of the first horizontal axis grid portion. A third connection terminal connected to a connection portion between the other end of the first horizontal axis grid portion, one end of the second main axis grid portion, and the other end of the second main axis grid portion. A fourth connection connected to a connection point with the other end of the second horizontal axis grid portion And the electric resistance values of the first and second main axis strain gauges and the first and second horizontal axis strain gauges are made equal and the resistance temperature coefficient is made equal, and the main axis direction The horizontal grid that is perpendicular to this changes the resistance value change generated by the difference in linear expansion coefficient between the measured object and the strain gauge, and the two combined resistance value changes generated from the resistance temperature coefficient due to temperature change. The heat-strain output component is formed to be uniform.

In order to achieve the above-described object, the strain gauge according to the invention described in claim 5 is an odd number of three or more strain gauges according to any one of claims 1 to 4. Are arranged on concentric circles at equiangular intervals of 360 ° / n, and the main axis direction of the reference strain gauge is used as the reference axis, and the other main axis directions of the remaining (n−1) strain gauges. Is shifted by 180 ° / n with respect to the reference axis, and when a bridge voltage is supplied to each input terminal of each strain gauge, the strain output output from each output terminal is maximum. Based on the output of a certain strain gauge and the installation angle position of the strain gauge that outputs the maximum strain, the maximum strain output and the main strain direction appearing on the object to be measured can be detected with a specified accuracy. It is characterized in that was.
In order to achieve the above-described object, the strain gauge according to the sixth aspect of the present invention is configured so that the three strain gauges A, B, and C are concentrically arranged at intervals of 120 degrees and the main axis of the first strain gauge A The second strain gauge B and the third strain gauge C are arranged by shifting +60 degrees and −60 degrees and the direction is set as a reference axis, and bridged to the input terminals of the strain gauges A, B, and C. When the voltage is applied, the strain output of the first strain gauge A is εa, the strain output of the second strain gauge B is εb, and the strain output of the third strain gauge C is εc. The strain output output from the strain gauge showing the maximum extreme value is obtained from the following equation (1),

さらに、被測定対象物における主ひずみ方向を、前記最大極値を示したひずみゲージの配置方向から求めることを特徴としている。
請求項７に記載した発明に係るひずみゲージは、上述した目的を達成するために、５個のひずみゲージＡ、Ｂ、Ｃ、Ｄ、Ｅを同心円上に７２度間隔であって且つ、第１のひずみゲージＡの主軸方向を基準軸として配置すると共に、第２のひずみゲージＢ、第３のひずみゲージＣ、第４のひずみゲージＤ、第５のひずみゲージＥを順次３６度ずらせて配置してなり、前記ひずみゲージＡ、Ｂ、Ｃ、Ｄ、Ｅの各入力端子にブリッジ電圧を供給することにより、前記第１のひずみゲージＡのひずみ出力がεａ、前記第２のひずみゲージＢのひずみ出力がεｂ、前記第３のひずみゲージＣのひずみ出力がεｃ、前記第４のひずみゲージＤのひずみ出力がεｄ、前記第５のひずみゲージＥのひずみ出力がεｅであるとしたとき、最大の極値を示すひずみゲージから出力される出力を、下記（２）式より求め、

Furthermore, the main strain direction in the measurement object is obtained from the arrangement direction of the strain gauge showing the maximum extreme value.
In order to achieve the above-described object, the strain gauge according to the invention described in claim 7 includes five strain gauges A, B, C, D, and E that are concentrically arranged at intervals of 72 degrees and the first The second strain gauge B, the third strain gauge C, the fourth strain gauge D, and the fifth strain gauge E are sequentially shifted by 36 degrees. By supplying a bridge voltage to the input terminals of the strain gauges A, B, C, D, and E, the strain output of the first strain gauge A is εa, and the strain of the second strain gauge B is When the output is εb, the strain output of the third strain gauge C is εc, the strain output of the fourth strain gauge D is εd, and the strain output of the fifth strain gauge E is εe, the maximum Strain game showing extreme values Obtain the output output from the following formula (2):

被測定対象物における主ひずみ方向を、前記最大極値を示したひずみゲージの配置方向から求めることを特徴としている。

The main strain direction in the object to be measured is obtained from the arrangement direction of the strain gauge showing the maximum extreme value.

According to the present invention, the first and second principal axis strain gauges connected to each of the two opposite sides of the equivalent bridge circuit, and the second connected to each of the other two sides adjacent to the two sides. A strain gauge in which the first and second horizontal axis strain gauges are integrally formed on the same substrate attached to an object to be measured, and four isosceles triangular areas or fan-shaped areas are formed by dividing a square or a circle by a diagonal line. When a region is hypothesized, the first and second main axis strain gauges are arranged opposite to each other with the intersection of the diagonal lines as symmetric, and are triangular or fan-shaped having a linear sensing part in the main axis direction or the horizontal axis direction. Formed on the first and second main axis grid portions, the first and second horizontal axis strain gauges are opposed to each other with the intersection point being symmetrical, and are linearly sensitized in the horizontal axis direction or the main axis direction. Part The electrical resistances of the first and second main axis strain gauges and the first and second horizontal axis strain gauges are formed in the triangular or fan-shaped first and second horizontal axis grid portions having The resistance value coefficient and the temperature coefficient of resistance are equalized, and the change in the resistance value and the temperature generated by the grid in the main axis direction and the horizontal axis direction orthogonal thereto are perceived by the difference in coefficient of linear expansion between the object to be measured and the strain gauge. By forming the thermal strain output components of the two synthesized resistance value changes generated from the resistance temperature coefficient due to changes to be equal,
First, the first and second main axis grid parts sense vertical strain, and the other first and second horizontal grid parts also have an aspect ratio according to the Poisson's ratio even in the horizontal strain. High sensitivity to reliably detect strain,
Secondly, the shapes of the four grid parts of the first and second main axis grid parts and the first and second horizontal axis grid parts are symmetric, the electric resistance is equal, and the resistance temperature coefficient is both equal. As a result, the inside of the circuit becomes an equivalent circuit, no zero point fluctuation occurs due to changes in the temperature coefficient of resistance, and it also affects the heat output generated from the difference in linear expansion coefficient between the measured object and the strain gauge. There is no, you can perform a stable and accurate strain measurement,
Thirdly, since the first and second main axis grid portions and the first and second horizontal axis grid portions are integrally and simultaneously formed on a single substrate, the specific resistance and In addition to the effect that the temperature coefficient of resistance and the thermoelectromotive force generated at the connection are made uniform, the size can be reduced, and the four gauge elements can be arranged in a very narrow area, so that they are exposed to the same temperature conditions. The temperature compensation is extremely accurate, and the sensitivity is higher than that of the conventional strain gauge (about 2.6 times). At the time of preparation for strain measurement, four strain gauges are attached to the object to be measured. Compared to the conventional strain gauge attachment, the labor required for soldering the gauge leads when connecting wires and bridges is greatly reduced, and there is also an adhesive layer between each gauge element and the object to be measured. Compared to the case where four sheets are bonded separately as in the past, it is attached at once. Homogenized from Rukoto, there is also an effect that.

Fourthly, since there is no need to match the resistance material of the gauge with the material of the object to be measured, or to perform special heat treatment or rolling, a highly versatile strain gauge can be provided at low cost.
Further, according to the strain measurement system according to the present invention, the number of odd numbers of 3 or more is used, concentric circles at equiangular intervals of 360 ° / n, and the principal strain direction of the strain gauge is set as a reference. It is arranged as a reference axis, and the main axis directions of the remaining (n-1) strain gauges are shifted by 180 ° / n with respect to the reference axis, and each input of each strain gauge is set. When a bridge voltage is supplied to a terminal, the output is output to the object under measurement based on the output of the strain gauge with the maximum strain output from each output terminal and the installation angle position of the strain gauge that outputs the maximum strain. By configuring so that the maximum strain output and the main strain direction can be detected with a predetermined accuracy, a strain gauge having the above characteristics can be arbitrarily attached to the object to be measured. In addition, the main strain direction and the maximum strain amount can be measured.

It is a top view which shows the pattern shape of the strain gauge which concerns on the 1st Embodiment of this invention. It is a top view which shows the pattern shape of the strain gauge which concerns on the 2nd Embodiment of this invention. It is a top view which shows the pattern shape of the strain gauge which concerns on the 3rd Embodiment of this invention. It is a top view which shows the pattern shape of the strain gauge which concerns on the 4th Embodiment of this invention. It is an equivalent circuit diagram which shows the Wheatstone bridge circuit formed with the strain gauge shown in FIG. It is a top view which shows the arrangement structure as an example of the strain analysis system performed using three strain gauges concerning the 6th Embodiment of this invention. It is a graph which shows the phase relationship of each strain output of a triaxial strain gauge. It is a top view which has arrange | positioned five strain gauges on a concentric circle at intervals of 72 degrees.

  Hereinafter, the present invention will be described through embodiments of the invention. However, the embodiments of the invention do not limit the invention according to the scope of claims, and are described in the embodiments. Not all combinations of features are essential to the solution of the present invention.

[First Embodiment]
The strain gauge according to the first embodiment of the present invention includes a first and second spindle strain gauges connected to each of two opposing sides of an equivalent bridge circuit, and another adjacent to the two sides. The strain gauge is formed by integrally forming the first and second horizontal axis strain gauges connected to each of the two sides on the same substrate attached to the object to be measured.
FIG. 1 is a plan view showing a pattern shape of a strain gauge according to the first embodiment of the present invention. When measuring the strain, the user directly or indirectly attaches the strain gauge to the object to be measured or the strain generating portion (not shown) of the transducer by means such as adhesion, sputtering, or thermal spraying.
The strain gauge shown in FIG. 1 is integrally formed on a substrate 10 as a main part thereof, and is connected to each of two opposing sides of an equivalent bridge circuit. 4 and a total of four strain gauges, i.e., first and second lateral strain gauges 3 and 4 connected to the other two sides adjacent to the two sides.
Each of the first and second main axis strain gauges 1 and 2 and the first and second horizontal axis strain gauges 3 and 4 is formed by a strain sensitive resistor. In addition, the first and second main-axis strain gauges 1 and 2 are assumed to be virtual when two square lines that are orthogonal to each other are divided in a square of the substrate region where the strain-sensitive resistor is laid. It is arranged in an equilateral triangular region.

More specifically, the strain-sensitive resistor is point-symmetric with respect to the intersection point P1 of the diagonal lines (in other words, axially symmetrical with the horizontal axis perpendicular to the principal axis direction passing through the intersection point P1), respectively along the principal axis direction. Triangular first and second main axis grid portions G1 and G2 which are arranged opposite to each other and are successively folded in the vicinity of the hypotenuse and the base of the isosceles triangle arranged opposite to each other in the main axis direction and have linear sensing parts in the main axis direction. Form.
The first and second horizontal axis strain gauges 3 and 4 are also installed in four isosceles triangular regions by dividing the inside of the square with diagonal lines, as described above. More specifically, the strain-sensitive resistor is point-symmetric about the intersection P1 of the diagonal (in other words, the axis in the principal axis direction passing through the intersection P1 is symmetric) along the horizontal axis direction. Triangular first and second horizontal grid portions that are arranged opposite to each other and are successively folded in the vicinity of the hypotenuse and the base of the isosceles triangle arranged opposite to each other in the horizontal axis direction and have linear sensing portions in the horizontal axis direction. G3 and G4 are formed.
The sensitive axis directions of the first and second main spindle strain gauges 1 and 2 are directions of line segments connecting small triangular indicators M1 and M2 shown as the reference of the present strain gauge. M1 and M2 are assumed to coincide with the main axis direction. The sensitive axis directions of the first and second lateral strain gauges 3 and 4 are transverse directions orthogonal to the sensitive axis directions of the first and second principal strain gauges 1 and 2, respectively. To match. At this time, the indicators M3 and M4 are attached so as to coincide with the horizontal axis direction.

The strain gauge shown in FIG. 1 is formed on the substrate 10 as another component, and is connected to a connection portion between one end of the first main axis grid portion G1 and one end of the second horizontal axis grid portion G4. The first connecting terminal T1, the second connecting terminal T2 connected to the connecting portion between the other end of the first main axis grid part G1 and one end of the first horizontal axis grid part G3, A third connection terminal T3 connected to a connection portion between the other end of the first horizontal axis grid portion G3 and one end of the second main axis grid portion G2, and the other end of the second main axis grid portion G2. A fourth connection terminal T4 connected to a connection point with the other end of the second horizontal axis grid part G4 (the strain gauge according to the first embodiment corresponds to claim 1). ).
As described above, the strain gauge according to the first embodiment of the present invention is connected to each of the first and second spindle strain gauges 1 and 2 and the other two sides adjacent to the two sides. Since the first and second horizontal axis strain gauges 3 and 4 are arranged symmetrically with respect to the intersection P1, the measurement of the strain amount in the principal axis direction and the measurement of the strain amount in the horizontal axis direction are performed simultaneously. The sensitivity S in the equivalent circuit is generally 1.0 in the principal axis direction, the horizontal axis direction depends on the Poisson's ratio ν, and the sensitivity is generally −0.3. .

Therefore, the sensitivity S in the equivalent circuit of the bridge is generally S = (1ε + 1ε) − (− 0.3ε−0.3ε) = 2.6.
Thus, when it has 2.6 times the sensitivity and the gauge factor K of the strain sensitive resistance material is K = 2.0, the gauge factor in the bridge circuit is 5.2.
In addition, the strain gauge according to the first embodiment of the present invention is configured as described above, and the first and second main axis strain gauges 1 and 2 and the first and second lateral axis strain gauges 3 are provided. 4 and 4 have point-symmetric (or axially symmetric) shapes, and the electric resistance values of the respective strain gauges are made equal. Further, the resistance temperature coefficients of the first and second main axis strain gauges 1 and 2 and the first and second horizontal axis strain gauges 3 and 4 are also made equal. Further, from the strain gauge pattern shape shown in FIG. 1, the sensitive axis directions of the first and second spindle strain gauges 1 and 2 are the same. Further, the directions of the sensitive axes of the first and second lateral strain gauges 3 and 4 also coincide with each other.
With this configuration, in the strain gauge according to the first embodiment of the present invention, the thermal strain output components in the main axis direction and the horizontal axis direction orthogonal to the main axis direction are equal. Thereby, the influence of the resistance change due to the temperature change in the main axis direction and the horizontal axis direction orthogonal to the main axis direction can be compensated equally. Therefore, when the ambient temperature changes, the changes in the resistance values of the four strain gauges are all equal, and even if the object to be measured is made of any material having a linear expansion coefficient, they are offset from each other. In the output of the above-described equivalent bridge circuit, the apparent distortion output and the drift with time change do not occur.

The first spindle strain gauge 1 and the second spindle strain gauge 2 are connected to two opposing sides of a Wheatstone bridge circuit (hereinafter simply referred to as “bridge circuit”) as an equivalent bridge circuit shown in FIG. The first and second horizontal axis strain gauges 3 and 4 are connected to the other two sides adjacent to each other. A bridge between a connection point a between the first main axis strain gauge 1 and the second horizontal axis strain gauge 4 and a connection point b between the second main axis strain gauge 2 and the first horizontal axis strain gauge 3. The voltage Ein is supplied via the connection terminals T3 of the first connection terminals T1 and T3, respectively.
Further, from between the connection point c between the second main axis strain gauge 2 and the second horizontal axis strain gauge 4 and the connection point d between the first main axis strain gauge 1 and the first horizontal axis strain gauge 3. The strain output voltage Eout can be taken out via the fourth connection terminal T4 and the second connection terminal T2.
As described above, the first to fourth connection terminals T1 to T4 are terminals for electrical connection between the bridge power source and the strain measuring device, and supply the bridge power source to the bridge circuit and measure the strain output to the strain measurement. It has an area suitable for fixing a gauge lead or lead wire for leading to a vessel by electric resistance welding (for example, spot welding), soldering or the like.

The strain sensitive resistance material forming each of the first and second main axis strain gauges 1 and 2, the first and second horizontal axis strain gauges 3 and 4, the wiring pattern, and the connection terminals T1 to T4 is optional. The resistance material can be applied. For example, Ni—Cr (based) alloy, Fe—Cr—Al alloy (trade names: Karma, K alloy, Evanome, KANTHAL, etc.), Pt—W alloy, Cu—Ni alloy (trade names: Advance, Constantan, Eureka) , Pt and Ti, or a semiconductor can be used in accordance with the application.
As a material which comprises the board | substrate 10, the thing of an appropriate material according to a use can be used for resin and Japanese paper, such as a polyimide, polyester, an epoxy, a phenol, for example.
The indicators M1 and M2 formed on the substrate 10 indicate the main axis directions of the first and second main axis strain gauges 1 and 2.
Indicators M3 and M4 indicate the horizontal axis directions of the first and second horizontal strain gauges 3 and 4.
These indexes M1 to M4 serve as marks when the strain gauge is attached to the object to be measured.

[Second Embodiment]
The strain gauge according to the second embodiment of the present invention includes a first and a second main axis strain gauge connected to each of two opposing sides of an equivalent bridge circuit, and another two adjacent to the two sides. It is a strain gauge in which the first and second horizontal axis strain gauges connected to each of the sides are integrally formed on the same substrate attached to the object to be measured. A feature of the strain gauge according to the second embodiment of the present invention is that the substrate region is a circular region. Depending on the shape and state of the object to be measured, such a circular strain gauge is required.
FIG. 2 is a plan view showing a pattern shape of a strain gauge according to the second embodiment of the present invention. When measuring the strain, the user attaches the strain gauge directly or indirectly to the object to be measured or the strain generating portion (not shown) of the transducer.
The strain gauges shown in FIG. 2 are formed on a substrate (not shown), and are connected to each of two opposing sides of the equivalent bridge circuit, the first and second main axis strain gauges 11 and 12, A total of four strain gauges including first and second lateral axis strain gauges 13 and 14 connected to each of the other two sides adjacent to the two sides are provided.
Each of the first and second principal axis strain gauges 11 and 12 and the first and second lateral axis strain gauges 13 and 14 are formed by strain sensitive resistors. In addition, the first and second main spindle strain gauges 11 and 12 have four sector regions shown when the circle of the substrate region on which the strain sensitive resistor is laid is divided by two dividing lines orthogonal to each other. It is arranged in.

More specifically, in the strain sensitive resistor, when four circular regions are virtually divided by dividing the inside of a circular substrate by dividing lines at intervals of 90 degrees, four strain gauges are formed in the four sector regions. The first and second main axis strain gauges 11 and 12 are arranged opposite to each other along the main axis direction with the intersection of the dividing lines as symmetry, and in the vicinity of the fan-shaped oblique side and arc portions arranged opposite to each other in the main axis direction. Fan-shaped first and second main spindle grid parts G11 and G12 are formed which are folded back in succession and have a linear sensing part in the main axis direction.
Similarly, the first and second horizontal axis strain gauges 13 and 14 are arranged opposite to each other along the horizontal axis direction orthogonal to the main axis direction, with the intersection point P11 of the dividing line being point-symmetric. The fan-shaped first and second horizontal axis grid portions G13 and G14 are formed which are sequentially folded in the vicinity of the sector-shaped hypotenuse and arc portions that are opposed to each other in the direction to have a linear sensing portion in the horizontal axis direction. .
The sensitive axis directions of the first and second main spindle strain gauges 11 and 12 are made to coincide with the axial directions indicated as the reference of the present strain gauge. The sensitive axis directions of the first and second horizontal strain gauges 13 and 14 are orthogonal to the sensitive axis directions of the first and second principal strain gauges 11 and 12, respectively. .

Further, the strain gauge shown in FIG. 2 includes, as another component, a first connection terminal connected to a connection portion between one end of the first main axis grid portion G11 and one end of the second horizontal axis grid portion G14. T11, a second connection terminal T12 connected to a connection part between the other end of the first main axis grid part G11 and one end of the first horizontal axis grid part G13, and the first horizontal axis grid part A third connection terminal T13 connected to a connection portion between the other end of G13 and one end of the second main spindle grid portion G12; the other end of the second main spindle grid portion G12; and the second horizontal axis grid. And a fourth connection terminal T14 connected to a connection point with the other end of the part G14 (the strain gauge according to the second embodiment corresponds to claim 2).
As described above, the strain gauge according to the second embodiment of the present invention is connected to each of the first and second spindle strain gauges 11 and 12 and the other two sides adjacent to the two sides. Since the first and second horizontal axis strain gauges 13 and 14 are arranged symmetrically with respect to the intersection P11, the measurement of the strain amount in the principal axis direction and the measurement of the strain amount in the horizontal axis direction have been described above. Can be done at the same time.

In addition, the strain gauge according to the second embodiment of the present invention is configured as described above, and the first and second main axis strain gauges 11 and 12 and the first and second lateral axis strain gauges 13 are provided. And 14 are made equal to each other. Further, the resistance temperature coefficients of the first and second main axis strain gauges 11 and 12 and the first and second horizontal axis strain gauges 13 and 14 are also made equal.
Further, from the pattern shape of the strain gauge shown in FIG. 2, the sensitive axis directions of the first and second spindle strain gauges 11 and 12 are the same. Furthermore, the sensitive axis directions of the first and second horizontal axis strain gauges 13 and 14 are also coincident with each other.
In this way, the first main axis grid part G11 and the second main axis grid part G13 are both formed on the axis object, and at the same time, the first horizontal axis grid part G12 and the second horizontal axis grid part G14 By configuring so that all the grid portions are axial objects, in the strain gauge according to the second embodiment of the present invention, the thermal strain output components in the main axis direction and the horizontal axis direction perpendicular thereto are equal. Thereby, the influence of the resistance change due to the temperature change in the main axis direction and the horizontal axis direction perpendicular thereto can be compensated equally. That is, even if this strain gauge is attached to an object to be measured made of a material having any linear expansion coefficient, when the ambient temperature changes, all the changes in resistance values in the four strain gauges are all. Since they are equal and cancel each other, the output of the above-described equivalent bridge circuit does not cause an apparent distortion output and drift over time. In other words, it is possible to realize a strain gauge in which the apparent strain due to temperature is not affected by the linear expansion coefficient of the measurement object.

As described in FIG. 5, the first to fourth connection terminals T11 to T14 are terminals for electrical connection with a strain measuring instrument having a power source, and are gauges for guiding strain output to the strain measuring instrument. It has an area suitable for fixing the lead or the lead wire by electric resistance welding (for example, spot welding), soldering or the like.
Any resistance material can be used for the resistance material forming each of the first and second main axis strain gauges 11 and 12 and the first and second horizontal axis strain gauges 13 and 14. For example, Ni—Cr (based) alloy, Fe—Cr—Al alloy (trade names: Karma, K alloy, Evanome, KANTHAL, etc.), Pt—W alloy, Cu—Ni alloy (trade names: Advance, Constantan, Eureka) , Pt and Ti, or a semiconductor can be used in accordance with the application.
As a material constituting the substrate, for example, resins such as polyimide, polyester, epoxy, phenol, and Japanese paper can be used according to the application.

[Third Embodiment]
The strain gauge according to the third embodiment of the present invention includes a first and second main axis strain gauges connected to each of two opposing sides of an equivalent circuit bridge circuit, and other adjacent to the two sides. The first and second horizontal strain gauges connected to each of the two sides are integrally formed on the same substrate attached to the object to be measured. Compared to the strain gauge according to the first embodiment of the present invention, the strain gauge according to the third embodiment of the present invention is different from the strain gauge according to the first embodiment of the present invention. In the first embodiment, the grid portion is perpendicular to the base of the isosceles triangle region, whereas in the third embodiment, the grid portion is parallel to the base pattern of the isosceles triangle region. The point is different.
FIG. 3 is a plan view showing a pattern shape of a strain gauge according to the third embodiment of the present invention. When measuring the strain, the user directly or indirectly attaches the strain gauge to the object to be measured or the strain generating portion (not shown) of the transducer by means such as adhesion, vapor deposition, or fusion. The strain gauge shown in FIG. 3 is formed on the substrate 20 as a main part thereof, and is connected to each of two opposing sides of the equivalent bridge circuit, and first and second spindle strain gauges 21 and 22; A total of four strain gauges including first and second horizontal axis strain gauges G23 and G24 connected to each of the other two sides adjacent to the two sides are provided.

Each of the first and second main axis strain gauges 21 and 22 and the first and second horizontal axis strain gauges G23 and G24 are formed of a strain sensitive resistance material. Moreover, the first and second principal axis strain gauges 21 and 22 are shown (imaginary) when the inside of the square of the substrate region where the resistance material pattern is laid is divided by two diagonal lines orthogonal to each other, It is arranged in four isosceles triangular regions.
More specifically, the strain-sensitive resistance material pattern is point-symmetric (or axially symmetric) from the diagonal intersection P21 and parallel to the base of an isosceles triangle arranged opposite to the horizontal axis direction orthogonal to the principal axis direction. In addition, the first and second main spindle grid portions G21 and G22 having a triangular shape having a linear sensing portion in the main axis direction and sequentially folded in the vicinity of the oblique side portion are formed. Further, the first and second horizontal axis strain gauges G23 and G24 are arranged symmetrically with respect to a point of intersection P21 of the diagonal line along the main axis direction, and are isosceles opposite to the main axis direction. Triangular first and second horizontal axis grid portions G23 and G24 are formed which are sequentially folded in the vicinity of the two hypotenuses of the triangle and have linear sensing portions in the horizontal axis direction.

The sensitive axis directions of the first and second main spindle strain gauges 21 and 22 are made to coincide with the axial direction indicated as the reference of the present strain gauge. The sensitive axis directions of the first and second lateral strain gauges 23 and 24 are orthogonal to the sensitive axis directions of the first and second principal strain gauges 23 and 24, respectively. .
Further, the strain gauge shown in FIG. 3 is formed on the substrate 20 as another component, and is connected to a connection portion between one end of the first main axis grid part G21 and one end of the second horizontal axis grid part G24. A first connection terminal T21 connected; a second connection terminal T22 connected to a connection portion between the other end of the first main axis grid portion G21 and one end of the first horizontal axis grid portion G23; A third connection terminal T23 connected to a connection portion between the other end of the first horizontal axis grid portion G23 and one end of the second main axis grid portion G22, and other than the second main axis grid portion G22 A fourth connection terminal T24 connected to a connection point between the end and the other end of the second horizontal axis grid part G24 (the strain gauge according to the third embodiment configured in this way Corresponding to claim 3).

As described above, the strain gauge according to the third embodiment of the present invention is connected to each of the first and second spindle strain gauges 21 and 22 and the other two sides adjacent to the two sides. Since the first and second horizontal axis strain gauges 23 and 24 are arranged symmetrically with respect to the intersection P21, the measurement of the strain amount in the principal axis direction and the measurement of the strain amount in the horizontal axis direction are performed simultaneously. be able to.
The strain gauge according to the third embodiment of the present invention is configured as described above, and the first and second main axis strain gauges 21 and 22 and the first and second lateral axis strain gauges 23. And 24 so that the electric resistance value of each of them is equal. Furthermore, the resistance temperature coefficients of the first and second main axis strain gauges 21 and 22 and the first and second horizontal axis strain gauges 23 and 24 are also made equal. Further, from the pattern shape of the strain gauge shown in FIG. 1, the sensitive axis directions of the first and second spindle strain gauges 21 and 22 are the same. Further, the sensitive axis directions of the first and second horizontal axis strain gauges 23 and 24 are also coincident with each other.

With this configuration, in the strain gauge according to the third embodiment of the present invention, the thermal strain output components in the main axis direction and the horizontal axis direction perpendicular to the main axis direction are equal. Thereby, the influence of the resistance change due to the temperature change in the main axis direction and the horizontal axis direction perpendicular thereto can be compensated equally. In other words, when the ambient temperature changes, the changes in the resistance values in the four strain gauges are all equal and cancel each other. Therefore, regardless of the material of the object to be measured to which the strain gauge is attached. Therefore, an apparent distortion output is not generated in the output of the above-described equivalent bridge circuit.
As described with reference to FIG. 5, the first to fourth connection terminals T21, T22, T23, and T24 are terminals for electrical connection with the power source and the strain measuring device, and supply bridge power to the strain gauge. Or a gauge lead or lead wire for guiding strain output to the strain measuring device has an area suitable for fixing by electrical resistance welding (for example, spot welding), soldering, or the like.
Any resistance material can be used for the resistance material forming each of the first and second main axis strain gauges 21 and 22 and the first and second horizontal axis strain gauges 23 and 24. For example, Ni—Cr (based) alloy, Fe—Cr—Al alloy (trade names: Karma, K alloy, Evanome, KANTHAL, etc.), Pt—W alloy, Cu—Ni alloy (trade names: Advance, Constantan, Eureka) , Pt and Ti, or a semiconductor can be used in accordance with the application.
As a material constituting the substrate 20, for example, a resin such as polyimide, polyester, epoxy, phenol, and Japanese paper can be used according to the application.

[Fourth Embodiment]
The strain gauge according to the fourth embodiment includes a first and second main axis strain gauges connected to two opposing sides of the equivalent bridge circuit, and the other two sides adjacent to the two sides. The first and second horizontal axis strain gauges connected to each of these are integrally formed on the same substrate attached to the object to be measured.
A feature of the strain gauge according to the third embodiment of the present invention is that the substrate region is a circular region. Depending on the shape and state of the object to be measured, such a circular strain gauge is required. Compared to the strain gauge according to the second embodiment described above, the strain gauge according to the fourth embodiment of the present invention is different from the strain gauge according to the second embodiment of the present invention. The formation direction of the grid part, which is the sensitive part, is orthogonal.
FIG. 4 is a plan view showing a pattern shape of a strain gauge according to the fourth embodiment of the present invention. When measuring the strain, the user attaches the strain gauge directly or indirectly to the object to be measured or the strain generating portion (not shown) of the transducer.
The strain gauge shown in FIG. 4 is formed on a substrate (not shown), and is connected to each of two opposing sides of the equivalent bridge circuit, and first and second main spindle strain gauges 31 and 32), A total of four strain gauges including first and second lateral axis strain gauges 33 and 34 connected to each of the other two sides adjacent to the two sides are provided.

Each of the first and second main axis strain gauges 31 and 32 and the first and second horizontal axis strain gauges 33 and 34 is formed of a strain sensitive resistance material, and a substrate region in which the resistance material is laid. Are arranged in four fan-shaped regions shown (imaginary) when the circle is divided by two dividing lines orthogonal to each other.
More specifically, when the circular sector is divided by dividing lines at intervals of 90 degrees and four fan-shaped regions are imagined, the first and second main axis strain gauges 31 and 32 are separated from the intersection P31 of the dividing lines. Symmetrically pointed and parallel to the base of the isosceles triangle oppositely arranged in the direction of the transverse axis perpendicular to the principal axis direction, and is sequentially folded near the two oblique sides and the arc portion and linear in the principal axis direction. The first and second main spindle grid portions G31 and G32 having a triangular shape are formed.
Further, the first and second horizontal axis strain gauges 33 and 34 are arranged so as to be point-symmetric with respect to the intersection P31 of the dividing line, respectively, along the principal axis direction, and arranged opposite to each other in the principal axis direction. Further, triangular first and second horizontal axis grid portions G33 and G34 are formed which are sequentially folded in the vicinity of the two oblique sides and the arc portion of the isosceles triangle and have a linear sensing portion in the horizontal axis direction.

The sensitive axis directions of the first and second main spindle strain gauges 31 and 32 are made to coincide with the main spindle direction shown as a reference of the present strain gauge. The sensitive axis directions of the first and second lateral strain gauges 33 and 34 are orthogonal to the sensitive axis directions of the first and second principal strain gauges 31 and 32, respectively. .
Further, the strain gauge shown in FIG. 4 includes, as another component, a first connection terminal connected to a connection portion between one end of the first main axis grid portion G31 and one end of the second horizontal axis grid portion G34. T31, a second connection terminal T32 connected to a connection part between the other end of the first main axis grid part G31 and one end of the first horizontal axis grid part G33, and the first horizontal axis grid part A third connection terminal T33 connected to a connection portion between the other end of G33 and one end of the second main spindle grid portion G32; the other end of the second main spindle grid portion G32; and the second horizontal axis grid. And a fourth connection terminal T34 connected to a connection point with the other end of the part G34.
As described above, the strain gauge according to the fourth embodiment of the present invention is connected to each of the first and second spindle strain gauges 31 and 32 and the other two sides adjacent to the two sides. Since the first and second horizontal axis strain gauges 33 and 34 are arranged symmetrically with respect to the intersection point P31, the measurement of the strain amount in the principal axis direction and the measurement of the strain amount in the horizontal axis direction are performed simultaneously. be able to.

In addition, the strain gauge according to the fourth embodiment of the present invention is configured as described above, and the first and second spindle strain gauges 31 and 32, and the first and second lateral strain gauges 33. And 34 so that the electric resistance value of each of them is equal. Furthermore, the resistance temperature coefficients of the first and second main axis strain gauges 37 and 32 and the first and second horizontal axis strain gauges 33 and 34 are also made equal. Further, from the pattern shape of the strain gauge shown in FIG. 4, the sensitive axis directions of the first and second spindle strain gauges 31 and 32 are the same. Further, the directions of the sensitive axes of the first and second lateral strain gauges 33 and 34 also coincide with each other.
With this configuration, in the strain gauge according to the fourth embodiment of the present invention, the thermal strain output components in the main axis direction and in the horizontal axis direction perpendicular thereto are equal. Thereby, the influence of the resistance change due to the temperature change in the main axis direction and the horizontal axis direction perpendicular thereto can be compensated equally. That is, when the ambient temperature changes, the resistance value changes in the four strain gauges are all equal and cancel each other, so that no apparent strain output is generated in the output of the above-described equivalent bridge circuit. It will be.

The first to fourth connection terminals (T31, T32, T33, T34) are terminals for electrical connection with a power source and a strain measuring instrument, and supply a bridge power source to a strain gauge or measure strain output of the strain measurement. It has an area suitable for fixing a gauge lead or lead wire for leading to a vessel by electric resistance welding (for example, spot welding), soldering or the like.
An arbitrary resistance material can be used for the strain sensitive resistance material forming each of the first and second main axis strain gauges 31 and 32 and the first and second horizontal axis strain gauges 33 and 34. For example, Ni—Cr (based) alloy, Fe—Cr—Al alloy (trade names: Karma, K alloy, Evanome, KANTHAL, etc.), Pt—W alloy, Cu—Ni alloy (trade names: Advance, Constantan, Eureka) , Pt and Ti, or a semiconductor can be used in accordance with the application.
As a material constituting the substrate, for example, resins such as polyimide, polyester, epoxy, phenol, and Japanese paper can be used according to the application.

[Fifth Embodiment]
The strain analysis system which concerns on the 5th Embodiment of this invention comprises the strain gauge of any one of Claims 1-4 according to 3 or more odd numbers.
FIG. 6 is a configuration diagram showing a configuration as an example of a strain analysis system according to the fifth embodiment of the present invention. In general, a strain analysis system according to the sixth embodiment of the present invention uses any one of the strain gauges of the first embodiment to the fourth embodiment as n odd numbers of three or more. These are arranged on concentric circles at equiangular intervals of 360 ° / n. However, FIG. 6 shows a case where n = 3 for convenience of explanation. That is, the strain analysis system shown in FIG. 6 includes strain gauges B and C in addition to the strain gauge A serving as a reference.
In a general strain analysis system, if the main axis direction of the reference strain gauge A is the reference axis, the main axis directions of the remaining (n−1) strain gauges B and C are 180 with respect to the reference axis. It will be installed by shifting by ° / n.
In general, in a strain analysis system including n strain gauges, which is an odd number of 3 or more, when a bridge voltage is supplied to each input terminal of the n strain gauges, a strain output output from each output terminal. Pay attention to the output of the strain gauge that has the maximum and the installation angle position of the strain gauge that outputs the maximum strain.

That is, based on the output of the strain gauge having the maximum strain output and the installation angle position of the strain gauge that outputs the maximum strain, the maximum strain output and the main strain direction that are output to the object to be measured are determined in advance. It can be detected with accuracy.
As a specific example of the strain analysis system according to the fifth embodiment of the present invention, a strain gauge having three strain gauges A, B, and C will be described as shown in FIG. During measurement, when a bridge voltage is supplied to the input terminals of the three strain gauges A, B, and C, the strain output of the strain gauge A is εa, the strain output of the strain gauge B is εb, and the strain of the strain gauge C Assume that the output indicates εc.
The outputs (εa, εb, εc) of these strain gauges equally distributed at 0 ± 60 ° shown in FIG. 6 change with COS2θ, and the polarity changes at the output branch point 45 ° of each gauge. In this case, the strain output (ε) output from the strain gauge showing the maximum extreme value can be obtained from the equation (1).

ここで、上記（１）式の誘導根拠を説明する。
今、０±６０゜に等配されたひずみゲージＡ，Ｂ，Ｃの出力をεａ，εｂ，εｃとする。
０±６０゜に等配されたひずみゲージ［εａ］，［εｂ］，［εｃ］の出力はＣＯＳ２θで出力が変化し、各ゲージの出力分岐点４５゜で極性が逆転する。
０±６０゜に等配されたひずみゲージ［εａ］，［εｂ］，［εｃ］の±極性を無くするために各出力を二乗和し平方根をとる。その時の出力は１．０である。
今、３軸のひずみゲージεａ＝０゜，εｂ＝６０゜，εｃ＝−６０゜に配置されている。
主ひずみが１の時、出力値はεａ；εａ＝ＣＯＳ（０゜）＝１
主ひずみが１の時、出力値はεｂ；εｂ＝ＣＯＳ（６０゜）＝０．５
主ひずみが１の時、出力値はεｃ；εｃ＝ＣＯＳ（−６０゜）＝−０．５
今、±極性を無くするためにの二乗和し平方根をとる。

Here, the grounds for guiding the above equation (1) will be described.
Now, let εa, εb, and εc be the outputs of strain gauges A, B, and C equally distributed at 0 ± 60 °.
The outputs of the strain gauges [εa], [εb], and [εc] equally distributed at 0 ± 60 ° change at COS2θ, and the polarity is reversed at the output branch point 45 ° of each gauge.
In order to eliminate the ± polarities of the strain gauges [εa], [εb], and [εc] equally distributed at 0 ± 60 °, the outputs are squared and the square root is obtained. The output at that time is 1.0.
Now, the triaxial strain gauges εa = 0 °, εb = 60 °, and εc = −60 ° are arranged.
When the main strain is 1, the output value is εa; εa = COS (0 °) = 1
When the main strain is 1, the output value is εb; εb = COS (60 °) = 0.5
When the main strain is 1, the output value is εc; εc = COS (−60 °) = − 0.5
Now, taking the square root of sum of squares to eliminate ± polarity.

０±６０゜に等配されたひずみゲージ［εａ］，［εｂ］，［εｃ］の出力はの総和は出力１．０の時に１．２２４７４４９の関係である。

The sum of the outputs of strain gauges [εa], [εb], and [εc] equally distributed at 0 ± 60 ° has a relationship of 1.2247449 when the output is 1.0.

Therefore, the constant that makes the value when the square root of the sum of the squares of the triaxial gauges is 1.0 is 1 / 1.247449 = 0.8164966
Therefore, the above equation (1) is obtained.
Further, the main strain direction in the object to be measured can be determined from the strain gauge arrangement direction showing the maximum extreme value among the three strain gauges A, B, and C.
That is, FIG. 6 shows a graph of the strain output phase of each strain gauge according to the deviation angle of the triaxial strain gauge. In FIG. 6, the horizontal axis indicates the strain direction (degrees), and the vertical axis indicates the output sensitivity (Ratio). From this figure, every time the axis deviates ± 15 ° from the strain axis direction, the main axis gauge changes. It can be seen that A → B → C.
The outputs εa, εb, and εc of the three strain gauges A, B, and C equally distributed at 60 ° change in output at COS 2θ and reverse in polarity at an output branch point of 45 °.
The phase of this output value is shown in FIG.
Table 1 shows the relationship between the output by the deviation angle of the triaxial gauge and the output ratio of the adjacent gauge.

For example, from Table 1 above, when the strain gauge A is in the 0 ° direction, the sensitivity of the strain gauge A is “1.00”, and the gauge sensitivities of the strain gauges B and C at the point shifted by ± 60 ° are respectively It turns out that it is "0.5".
Since the output branch point is in the 45 ° direction of each of the three gauge axes, 45 ° / 3 = 15 °, and the strain gauge showing the maximum extreme value with respect to strain from any (unknown) direction is 15 It can be seen that the main axis direction is shown within °.
For example, when the strain gauge B shows the maximum output value, it is 60 ° ± 15 ° or 150 ° ± 15 ° from Table 1, and 45 ° to 75 ° or 135 ° to the reference axis (0 °). It can be seen that the principal axis (principal strain) direction exists in the angular direction of 165 °.
Next, a description will be given of a method for obtaining a correction value of a deviation angle and a strain output by using three output target tables (tables) of three strain gauges with a temporary axis (A axis) as a reference angular position.
Table 2 is an output comparison table of the strain gauge A, Table 3 is an output comparison table of the strain gauge C, and Table 4 is an output comparison table of the strain gauge B.

In the leftmost column of Table 2, the names of strain gauges (Gauge A, Gauge B, Gauge C), the second column from the left is the spindle gage misalignment angle (0 ° and 90 ° spindle gauge angle ± 15 °), 3 from the left The column is the output when the output of the second column is reversed, the output of the main axis gauge angle 90 ° ± 15 °, the output ratio of Gauge A, Gauge B, Gauge C and adjacent sides (B / C, A / B, C / A).
Gauge A indicates an output of 0 ± 15 ° and a polarity opposite to that of 90 ± 15 °. At this time, 0 ° is the same output as 180 ° -180 °, and 90 ° is the same output as 270 ° -90 °.
GaugeC indicates an output of 30 ± 15 ° and a polarity opposite to that of 120 ± 15 °. At this time, 30 ° is the same output as 210 ° -150 °, and 120 ° is the same output as 300 ° -60 °.
Gauge B indicates an output of 60 ± 15 ° and a polarity opposite to that of 150 ± 15 °. At this time, 60 ° is the same output as 240 ° -120 °, and 150 ° is the same output as 330 ° -30 °.

Here, one output example, that is, Gauge A; −2460 μεh, Gauge B; 1394 με h, Gauge C; 1029 με h will be described. Here, μεh is an output unit approximately 2.6 times higher than με as an output unit of the strain gauge of the present invention.
Here, assuming that the output of Gauge A is −2460 μεh, the output of Gauge B is 1394 με h, and the output of Gauge C is 1029 με h, using the output comparison table of Tables 2 to 4, the deviation angle and The correction value is obtained as follows.
1) When the strain gauge A is attached to a strain measurement object as a temporary axis (0 °), this direction is set as a reference direction point.
2) Looking at the maximum absolute value output value, use Table 2 (Table A) when Gauge A is high, Table 3 (Table B) when Gauge B is high, and Table 4 (Table C) when Gauge C is high. .
3) Look for the range of the maximum output value in Table 2 to Table 4.
Here, since the maximum output value from Gauge A is minus (−2460 μεh), the Gauge A column in the rightmost column of Table 2 is targeted.
4) Further, the value of the output ratio B / C = 1394 μεh / 1029 μεh = 1.355 of the adjacent strain gauges B and C is obtained.
5) Therefore, when the output ratio in the rightmost column of Table 2 is searched for a value close to 1.355, it is 1.45 when 87 ° in the third column from the left, and 88 ° in the second column from the left. Since it is 1.28 at the time, 87.5 ° in the middle is the required deviation angle.

6) Next, the main strain amount of the correction value is obtained from the strain amount ε = 2460 μεh of the deviation angle of θ = 87.5 °.
ε / [COS2θ] = 2469 μεh
Get.
From this, the direction of the main strain is 87.5 ° from the reference axis of the strain gauge A, and it can be confirmed (confirmed) that a strain of 2469 μεh is generated.

[Sixth Embodiment]
Furthermore, as a further specific example of the strain analysis system according to the sixth embodiment of the present invention, as shown in FIG. 8, five strain gauges A, B, C, D, and E are arranged at 72 ° intervals on concentric circles. The strain analysis system arranged in can be configured.
Hereinafter, the strain analysis system shown in FIG. 8 will be described. The strain analysis system shown in FIG. 8 is arranged with the main axis direction of the strain gauge A as the reference axis (0 °), and the other strain gauges B to E are sequentially shifted by 36 °.
During measurement, when a bridge voltage is supplied to each input terminal of the strain gauges A to E, the strain output of the strain gauge A is εa, the strain output of the strain gauge B is εb, the strain output of the strain gauge C is εc, and the strain gauge D , And the strain output of the strain gauge E is εe.
The outputs εa, εb, εc, εc, and εe of these strain gauges equally distributed at 0 ± 36 ° shown in FIG. 8 also change with the COS2θ with respect to the rotation angle 2θ, and at the output branch point 36 ° of each gauge. The polarity is reversed.

Since the output branch point is in the 45 ° direction of each of the five gauge shafts, 45 ° / 5 = 9 °.
It can be seen that the gauge showing the maximum extreme value with respect to strain from an arbitrary direction (unknown direction) shows the main axis (main strain) within 9 °.
In this case, the strain output (ε) output from the strain gauge showing the maximum extreme value can be obtained from the following equation (2).

ここで、上記（２）式の誘導根拠を説明する。
今、０±３６゜に等配されたひずみゲージＡ，Ｂ，Ｃ，Ｄ，Ｅの出力をεａ，εｂ，εｃ，εｄ，εｅとする。
０±３６゜に等配されたひずみゲージεａ，εｂ，εｃ，εｄ，εｅ出力は、ＣＯＳ２θで出力が変化し，各ゲージの出力分岐点４５゜で極性が逆転する。
０±３６゜に等配されたひずみゲージεａ，εｂ，εｃ，εｄ，εｅの±極性を無くすため、二乗和し平方根とる。その時の出力は１．０である。
今、５軸のひずみゲージεａ＝０゜、εｂ＝３６゜、εｃ＝７２゜、εｄ＝１０８゜、εｄ＝１４４゜に配置されている。
主ひずみが１の時、出力値εａは； εａ＝ＣＯＳ（０゜）＝１
主ひずみが１の時、出力値εｂは； εｂ＝ＣＯＳ（３６゜）＝０．８０９
主ひずみが１の時、出力値εｃは； εｃ＝ＣＯＳ（７２゜）＝０．３０９
主ひずみが１の時、出力値εｄは； εｄ＝ＣＯＳ（１０８゜）＝−０．３０９
主ひずみが１の時、出力値εｅは； εｅ＝ＣＯＳ（１４４゜）＝−０．８０９
今、±極性を無くするために二乗和し平方根をとる。

Here, the basis of the above equation (2) will be described.
Now, let εa, εb, εc, εd, and εe be the outputs of strain gauges A, B, C, D, and E equally distributed at 0 ± 36 °.
The outputs of strain gauges εa, εb, εc, εd, and εe equally distributed at 0 ± 36 ° change at COS2θ, and the polarity is reversed at the output branch point 45 ° of each gauge.
In order to eliminate the ± polarities of the strain gauges εa, εb, εc, εd, and εe equally distributed at 0 ± 36 °, the sum of squares is taken to obtain the square root. The output at that time is 1.0.
Now, the five-axis strain gauges εa = 0 °, εb = 36 °, εc = 72 °, εd = 108 °, and εd = 144 °.
When the main strain is 1, the output value εa is: εa = COS (0 °) = 1
When the main strain is 1, the output value εb is: εb = COS (36 °) = 0.809
When the main strain is 1, the output value εc is: εc = COS (72 °) = 0.309
When the main strain is 1, the output value εd is: εd = COS (108 °) = − 0.309
When the main strain is 1, the output value εe is: εe = COS (144 °) = − 0.809
Now, in order to eliminate the ± polarity, the square sum is taken and the square root is taken.

３６゜に等配されたひずみゲージεａ，εｂ，εｃ，εｄ，εｅの出力の総和は、出力１．０の時に１．５８の関係である。
従って５軸ゲージの二乗和を平方根した時の値を１．０にする定数は、１／１．５８＝０．６３２である。
よって、上記（２）式が成立することとなる。

The sum of the outputs of the strain gauges εa, εb, εc, εd, and εe equally distributed at 36 ° has a relationship of 1.58 when the output is 1.0.
Therefore, the constant that makes the value when the square root of the sum of squares of the 5-axis gauge is 1.0 is 1 / 1.58 = 0.632.
Therefore, the above equation (2) is established.

[Other Embodiments]
The strain analysis system according to the embodiment of the present invention is not limited to the above-described and illustrated embodiment, and can be variously modified without changing the gist thereof.
For example, the strain analysis system may be configured by increasing the number of strain gauges described above to 5, 7, 9, or 11.
When the number of strain gauges is increased to 1, 3, 5, 7, or 9, “maximum strain output range indicated by the main gauge”, “main gauge sensing axis ± direction” and “output” “Calculation constants” are shown in Table 5.

The range of the maximum output value is the output accuracy indicated by the maximum strain output of the number of strains.
As can be seen from Table 5 above, the accuracy of “main gauge sensing axis ± direction” was “± 15 ° direction” when the number of strain gauges was 3, but “± 9 ° direction” when 5 strain gauges were used. In the case of 7 sheets, the detection accuracy is improved as in “± 6.4 ° direction”, in the case of 9, “± 5 ° direction”, and in the case of 11 sheets, “± 4 ° direction”.
Incidentally, the strain output when seven strain gauges are attached to the object to be measured at equal angular intervals is as shown in the following equation (3) using the output calculation constant from Table 5 above.

尚、複数（奇数に限る）のひずみゲージは、図６に示すように、１点を中心として半径方向に間隔を開けて、被測定体に添着するようにしたが、１点（同心軸）を中心としてすべてのひずみゲージを３段、５段、７段というように、重ね合わせてもよい。このようにした場合、より狭い範囲（極部的）でのひずみ解析をより高精度に行うことができる。

In addition, as shown in FIG. 6, a plurality of strain gauges (limited to odd numbers) are attached to the object to be measured with a gap in the radial direction centered at one point, but one point (concentric axis). All the strain gauges may be superposed such that the third, fifth, and seventh stages are centered on each other. In this case, strain analysis in a narrower range (extremely) can be performed with higher accuracy.

1,11,21,31 1st main axis gauge 2,12,22,32 2nd main axis gauge 3,13,23,33 1st horizontal axis gauge 4,14,24,34 2nd horizontal axis gauge 10, 20 Substrate G1, G11, G21, G31 First main axis grid G2, G12, G22, G32 Second main axis grid G3, G13, G23, G33 First horizontal axis grid G4, G14, G24, G34 Second Horizontal grid P1, P11, P21, P31 Intersection T1-T4, T11-T14, T21-T24, T31-T34 Connection terminal

Claims (7)

  First and second principal axis strain gauges connected to each of two opposite sides of the equivalent bridge circuit, and first and second laterals connected to each of the other two sides adjacent to the two sides. A strain gauge in which an axial strain gauge is integrally formed on the same substrate attached to an object to be measured, and when the square is divided by diagonal lines and four isosceles triangular regions are assumed, the first and first The two main axis strain gauges are arranged opposite to each other along the main axis direction with the intersection of the diagonal lines as symmetric, and are sequentially folded in the vicinity of the hypotenuse and the base of each isosceles triangle arranged opposite to the main axis direction so as to be linear in the main axis direction. Formed in triangular first and second main axis grid portions having a shape-sensitive part, and the first and second horizontal axis strain gauges are symmetrical with respect to the intersection point. A triangle having a linear sensory portion in the horizontal axis direction, which is arranged opposite to each other along the horizontal axis direction orthogonal to the direction and which is sequentially folded in the vicinity of the hypotenuse and the base of each isosceles triangle arranged opposite to the horizontal axis direction. Formed in the first and second horizontal axis grid portions and connected to a connection portion between one end of the first main axis grid portion and one end of the second horizontal axis grid portion. A connection terminal, a second connection terminal connected to a connection portion between the other end of the first main axis grid portion and one end of the first horizontal axis grid portion, and other than the first horizontal axis grid portion A third connection terminal connected to a connection portion between the end and one end of the second main axis grid portion; and the other end of the second main axis grid portion and the other end of the second horizontal axis grid portion. A fourth connection terminal connected to a connection point, and the first and second spindle strains And the first and second horizontal axis strain gauges are made equal to each other and the temperature coefficient of resistance is made equal, and the grid in the main axis direction and the horizontal axis direction perpendicular thereto is the object to be measured. It was formed so that the thermal strain output components of the two combined resistance value changes generated from the resistance value coefficient caused by temperature change and the resistance value change generated by sensing from the difference in linear expansion coefficient with the strain gauge were made uniform. Characteristic strain gauge.   First and second principal axis strain gauges connected to each of two opposite sides of the equivalent bridge circuit, and first and second laterals connected to each of the other two sides adjacent to the two sides. A strain gauge in which an axial strain gauge is integrally formed on the same substrate attached to an object to be measured, and when the circular sector is divided by dividing lines at intervals of 90 degrees and four sector regions are assumed, The first and second main axis strain gauges are opposed to each other along the main axis direction with the intersection of the dividing lines as symmetry, and are sequentially folded in the vicinity of the fan-shaped hypotenuse and arc portions arranged opposite to each other in the main axis direction. Formed in fan-shaped first and second main axis grid portions having linear sensing portions in the direction, and the first and second horizontal axis strain gauges are symmetrical with respect to the intersection of the dividing lines, Respectively A fan having a linear sensory section in the horizontal axis direction, which is disposed oppositely along the horizontal axis direction orthogonal to the axial direction, and is sequentially folded in the vicinity of the oblique side and arc portions of the fan shape disposed opposite to the horizontal axis direction. Formed in the first and second horizontal axis grid portions and connected to a connection portion between one end of the first main axis grid portion and one end of the second horizontal axis grid portion. A connection terminal, a second connection terminal connected to a connection portion between the other end of the first main axis grid portion and one end of the first horizontal axis grid portion, and other than the first horizontal axis grid portion A third connecting terminal connected to a connecting portion between the end and one end of the second main axis grid part; the other end of the second main axis grid part; and the other end of the second horizontal axis grid part A fourth connection terminal connected to the connection point of the first and second spindle strain gates And the first and second horizontal axis strain gauges have the same electrical resistance value and the same temperature coefficient of resistance, and the grid in the main axis direction and the horizontal axis direction perpendicular thereto are the object to be measured and the strain gauge. The thermal strain output component of the two combined resistance value changes generated from the resistance value coefficient generated by the difference in linear expansion coefficient and the resistance temperature coefficient due to the temperature change is made uniform. Strain gauge.   First and second principal axis strain gauges connected to each of two opposite sides of the equivalent bridge circuit, and first and second laterals connected to each of the other two sides adjacent to the two sides. A strain gauge in which an axial strain gauge is integrally formed on the same substrate attached to an object to be measured, and when the square is divided by diagonal lines and four isosceles triangular regions are assumed, the first and first The two principal axis strain gauges are arranged opposite to each other along the horizontal axis direction orthogonal to the main axis direction with the intersection of the diagonal lines as symmetry, and are sequentially folded in the vicinity of two oblique sides of the isosceles triangle arranged opposite to the horizontal axis direction. Formed in triangular first and second main axis grid parts having linear sensing parts in the main axis direction, and the first and second horizontal axis strain gauges are symmetrical about the intersection point, So A first triangular shape having a linear sensing part in the horizontal axis direction, which is arranged in the vicinity of the two hypotenuses of the isosceles triangle arranged opposite to each other along the main axis direction. And a first connection terminal formed on the second horizontal axis grid part and connected to a connection part between one end of the first main axis grid part and one end of the second horizontal axis grid part, A second connection terminal connected to a connection portion between the other end of the first main axis grid portion and one end of the first horizontal axis grid portion; the other end of the first horizontal axis grid portion; A third connection terminal connected to a connection portion with one end of the second spindle grid portion, and a connection point between the other end of the second spindle grid portion and the other end of the second horizontal grid portion. A fourth connecting terminal, and the first and second main axis strain gauges and the The electric resistance values of the first and second horizontal axis strain gauges are made uniform and the temperature coefficient of resistance is made uniform, and the grid in the main axis direction and the horizontal axis direction orthogonal thereto is a line between the object to be measured and the strain gauge. A strain gauge formed so that the thermal strain output components of the two combined resistance value changes generated from the resistance temperature coefficient caused by the temperature change and the resistance value change generated by sensing from the difference in expansion coefficient are equal. .   First and second principal axis strain gauges connected to each of two opposite sides of the equivalent bridge circuit, and first and second laterals connected to each of the other two sides adjacent to the two sides. A strain gauge in which an axial strain gauge is integrally formed on the same substrate attached to an object to be measured, and when the circular sector is divided by dividing lines at intervals of 90 degrees and four sector regions are assumed, The first and second main axis strain gauges are arranged opposite to each other along the horizontal axis direction orthogonal to the main axis direction with the intersection of the dividing lines as symmetry, and in the vicinity of each oblique side portion of the sector shape arranged opposite to the horizontal axis direction. It is formed in fan-shaped first and second main axis grid portions that are sequentially folded and have a linear sensing part in the main axis direction, and the first and second horizontal axis strain gauges are symmetrical with respect to the intersection point. As above, respectively Triangular first and second laterally arranged in the vicinity of the two hypotenuses of the sector shape opposed to each other along the axial direction and having linear sensing parts in the secondary axial direction. A first connection terminal formed on an axis grid portion and connected to a connection portion between one end of the first main axis grid portion and one end of the second horizontal axis grid portion; and the first main axis A second connection terminal connected to a connection portion between the other end of the grid portion and one end of the first horizontal axis grid portion; the other end of the first horizontal axis grid portion; and the second main axis grid. A fourth connection terminal connected to a connection point between the third connection terminal connected to the connection part with one end of the part, the other end of the second main axis grid part, and the other end of the second horizontal axis grid part. Connecting terminals, the first and second main axis strain gauges and the first and second The electric resistance values of the axial strain gauges are made uniform and the temperature coefficient of resistance is made uniform, and the grid in the main axis direction and the horizontal axis direction perpendicular to the main axis direction is sensitive to the difference in linear expansion coefficient between the measured object and the strain gauge. The strain gauge is formed so that the thermal strain output components of two synthesized resistance value changes generated from the resistance value coefficient generated by the temperature change and the resistance temperature coefficient due to the temperature change are equalized.   The strain gauge according to any one of claims 1 to 4 is used as a reference on concentric circles at equiangular intervals of 360 ° / n using n which is an odd number of 3 or more. The main axis direction of the strain gauge is arranged as a reference axis, and the other main axis directions of the remaining (n-1) strain gauges are shifted by 180 ° / n with respect to the reference axis. When a bridge voltage is supplied to each input terminal of each strain gauge, based on the output of the strain gauge that outputs the maximum strain from each output terminal and the installation angle position of the strain gauge that outputs the maximum strain A strain analysis system configured to be able to detect a maximum strain output and a main strain direction appearing on an object to be measured with a predetermined accuracy. The strain analysis system according to claim 5, wherein the three strain gauges A, B, and C are arranged concentrically at intervals of 120 degrees and the principal axis direction of the first strain gauge A is used as a reference axis, and the second The strain gauges B and the third strain gauges C are shifted by +60 degrees and −60 degrees, and a bridge voltage is supplied to each input terminal of the strain gauges A, B, and C, whereby the first When the strain output of the strain gauge A is εa, the strain output of the second strain gauge B is εb, and the strain output of the third strain gauge C is εc, output from the strain gauge showing the maximum extreme value. The strain output to be obtained is obtained from the following equation (1),

Furthermore, the strain analysis system characterized by calculating | requiring the main strain direction in a to-be-measured object from the arrangement | positioning direction of the strain gauge which showed the said maximum extreme value. 6. The strain analysis system according to claim 5, wherein the five strain gauges A, B, C, D, and E are concentrically arranged at intervals of 72 degrees and the main axis direction of the first strain gauge A is set as a reference axis. The second strain gauge B, the third strain gauge C, the fourth strain gauge D, and the fifth strain gauge E are sequentially shifted by 36 degrees, and the strain gauges A, B, C are arranged. , D and E by supplying a bridge voltage to the first strain gauge A, the strain output of the first strain gauge A is εa, the strain output of the second strain gauge B is εb, and the third strain gauge C The output output from the strain gauge showing the maximum extreme value is εc, the strain output of the fourth strain gauge D is εd, and the strain output of the fifth strain gauge E is εe. To the following ( 2) From the formula,

A strain analysis system characterized in that a main strain direction in an object to be measured is obtained from an arrangement direction of a strain gauge showing the maximum extreme value.

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