JP4255926B2 - Strain and temperature measuring device - Google Patents

Description

  In order to investigate the strength, behavior, safety, etc. of various materials and structures in the fields of machinery, architecture, civil engineering, etc., the present invention measures the temperature of the various materials or the structures, and the various materials or the structures. The present invention relates to an apparatus for measuring physical quantities such as strain, displacement, load, pressure, and torque of an object.

  When measuring strain generated in an object using a resistance-type strain gauge (a strain gauge whose resistance value changes according to the strain), in order to detect a minute resistance value change of the strain gauge attached to the object, A bridge circuit including the strain gauge (specifically a Wheatstone bridge circuit) is used. Then, while applying a power supply voltage to the bridge circuit, a voltage signal corresponding to a change in the resistance value of the strain gauge is output from the bridge circuit, and a strain is generated based on the voltage signal (a voltage signal obtained by amplifying the voltage signal). Measurement is performed. In such a strain measurement, a strain gauge is usually incorporated in a bridge circuit via a connecting wire such as a lead wire, and the bridge circuit applies a power supply voltage to the bridge circuit or outputs an output voltage signal of the bridge circuit. It is connected to a measuring instrument to be processed through a connecting wire such as a lead wire.

  In such strain measurement, due to the influence of the measurement environment and deformation of the measurement object at the time of measurement, the measurement object may change in temperature, and the temperature of the strain gauge may also change. In this case, in the strain gauge, in addition to the resistance value change caused by the strain of the measurement object, the resistance value change caused by the temperature change occurs. For this reason, an error that cannot be ignored when the distortion of the measurement object is obtained from the output voltage of the bridge circuit may be included.

  Therefore, the temperature characteristics of the strain gauge are examined in advance, a temperature sensor (thermocouple) is installed in the vicinity of the object to be measured, the temperature is measured, and an error caused by the temperature characteristics is corrected. It has been known. However, in this measurement method, in addition to the strain gauge lead wire, it is necessary to separately extend the thermocouple lead wire to the vicinity of the object to be measured. For this reason, there is a problem that the installation work takes time and costs increase, and there is a possibility that the measurement accuracy may be lowered when the thermocouple contact cannot be installed near the strain gauge.

  In order to solve such a problem, the present applicant has proposed a method of forming a thermocouple with a lead wire connected to a strain gauge and measuring the temperature together with the strain of the measurement object (for example, Patent Document 1). . In the strain measuring method of Patent Document 1, a bridge formed by connecting a strain gauge attached to a measurement object using a connection method of any one of a 1 gauge, a 3 gauge method, a 2 gauge method, and a 4 gauge method. Using a circuit, two of the lead wires are made of different materials to form a thermocouple contact in the vicinity of the strain gauge. Then, the strain and temperature are obtained using the output voltage of the bridge circuit when a bridge power supply voltage (DC voltage) is applied and the output voltage of the thermocouple when no bridge power supply voltage is applied. In addition, the 4-gauge method is usually used when forming a strain gauge type transducer for measuring physical quantities such as displacement, load, pressure, etc. of the measurement object in addition to directly measuring the strain of the measurement object. The strain gauge type transducer is formed by sticking four strain gauges forming a bridge circuit to a strain generating body so that the strain generating body generates strain according to the physical quantity of the object to be measured. The physical quantity of the measurement object is measured from the strain of the strain generating body.

However, in the measurement method of Patent Document 1, since strain is measured when a bridge power supply voltage is applied and temperature is measured when no bridge power supply voltage is applied, strain and temperature cannot be measured simultaneously. For this reason, when the temperature changes during strain measurement, there is a disadvantage that the strain cannot be obtained by appropriately correcting an error caused by the temperature characteristics of the strain gauge. In particular, the above inconvenience becomes significant when measuring a strain that dynamically changes (changes with time) or a physical quantity that causes strain of a strain-generating body of a strain gauge transducer.
JP 2000-009552 A

  The present invention eliminates such inconvenience and forms a thermocouple with a lead wire connected to a strain gauge, and can simultaneously measure strain and temperature of a measurement object or a strain generating body of a strain gauge transducer. To provide a measuring apparatus capable of easily and accurately obtaining a physical quantity that causes strain of a measurement object or strain of a strain-generating body of a strain gauge transducer even when the temperature changes during measurement. With the goal.

  The strain and temperature measuring device according to the first aspect of the present invention for solving the above-described problem forms a bridge circuit having one strain gauge attached to a measurement object according to a 1-gauge 3-wire method, By making two lead wires out of three lead wires connected to one strain gauge different from each other, a thermocouple contact is formed in the vicinity of the strain gauge, and the output voltage of the bridge circuit A measuring device for obtaining strain and temperature of the object to be measured from a signal, an AC power source as a power source of the bridge circuit, and an AC voltage of an output voltage signal of the bridge circuit to which a power source voltage is applied from the AC power source Detecting a component, outputting a signal corresponding to the distortion of the measurement object from the detected AC voltage component, and detecting a DC voltage component of the output voltage signal of the bridge circuit, Be from a DC voltage component that issued and a temperature signal output means for outputting a signal corresponding to the temperature of the measurement object, characterized in.

  According to the strain and temperature measuring device of the first aspect, the bridge circuit having one strain gauge attached to the measurement object is formed according to the 1 gauge 3-wire method. That is, a bridge circuit having the one strain gauge on one side and a resistor having a fixed resistance value on the other three sides is formed. The one strain gauge includes two lead wires for connecting the one strain gauge and another resistor to form a bridge circuit, and a lead wire for taking out the output voltage of the bridge circuit. A total of three lead wires are connected. At this time, two lead wires out of the three lead wires connected to the strain gauge are made of different materials from each other, so that the vicinity of the strain gauge (more specifically, two lead wires made of different materials) The end portion on the strain gauge side (however, the strain gauge and wiring included between the end portions of the two lead wires are also included), and a thermocouple contact is formed.

  According to the strain and temperature measuring device of the first aspect, the resistance value of the strain gauge changes according to the strain of the measurement object, and the voltage signal output from the bridge circuit corresponds to the change of the resistance value. Change. Further, a thermoelectromotive force is generated by a thermocouple having a contact point in the vicinity of the strain gauge in accordance with the temperature of the measurement object, and a voltage signal output from the bridge circuit changes in accordance with the thermoelectromotive force. At this time, since an AC power supply is used as the power supply for the bridge circuit, the change in the voltage signal corresponding to the distortion is caused by an AC component in the output voltage signal (specifically, in phase with the power supply voltage of the AC power supply). It appears as a change in the amplitude of the AC component. The change in the voltage signal according to the temperature appears as a change in the magnitude of the direct current component in the output voltage signal. In other words, the output voltage signal of the bridge circuit to which the power supply voltage is applied from the AC power supply is a combination of these AC components and DC components. Therefore, by detecting the alternating current component of the output voltage signal by the strain signal output means, it is possible to obtain a measurement value signal corresponding to the change in the resistance value of the strain gauge. Can be requested. Further, by detecting the direct current component of the output voltage signal by the temperature signal output means, it is possible to obtain a measurement value signal corresponding to the temperature change of the measurement object, and thereby the temperature of the measurement object. Can be requested. Therefore, a thermocouple can be formed with a lead wire connected to a strain gauge, and the strain and temperature of the measurement object can be measured simultaneously. As a result, even when the temperature changes during measurement, the strain of the measurement object can be easily measured. Can be obtained with high accuracy.

  In addition, the strain and temperature measuring device according to the second aspect of the present invention for solving the above-described problem includes a bridge circuit having two strain gauges connected in series, at least one of which is attached to a measurement object. A thermocouple is formed in the vicinity of the strain gauge by forming two lead wires out of three gauge wires formed in accordance with the two-gauge method and connected to the series circuit of the two strain gauges. A measuring device that forms a contact point and obtains strain and temperature of the object to be measured from an output voltage signal of the bridge circuit, the AC power source being a power source of the bridge circuit, and the power source voltage applied from the AC power source A distortion signal output means for detecting an AC voltage component in the output voltage signal of the bridge circuit and outputting a signal corresponding to the distortion of the measurement object from the detected AC voltage component; Detects a DC voltage component of the power voltage signal and the DC voltage component the detected anda temperature signal output means for outputting a signal corresponding to the temperature of the measurement object.

  According to the strain and temperature measurement device of the second aspect, a bridge circuit having two strain gauges connected in series, at least one of which is attached to a measurement object, is formed according to the 2-gauge method. That is, a bridge circuit having the two strain gauges on two adjacent sides and a resistor having a fixed resistance value on the other two sides is formed. In the series circuit of the two strain gauges, two lead wires for connecting the two strain gauges and another resistor to form a bridge circuit and the two strain gauges are connected in series. A total of three lead wires are connected to the lead wire for taking out the output voltage of the bridge circuit from the connecting portion to be connected. At this time, among the three lead wires connected to the series circuit of the two strain gauges, two lead wires are made of different materials from each other, so that the vicinity of the two strain gauges (more specifically, The end of the two lead wires made of different materials on the strain gauge side (however, the strain gauge and wiring included between the ends of the two lead wires are also included) to form a thermocouple contact .

  Then, according to the strain and temperature measuring device of the second aspect, the resistance value of the strain gauge changes according to the strain of the measurement object, and the resistance value changes according to the change of the resistance value, as in the first aspect. The voltage signal output from the bridge circuit changes. Further, a thermoelectromotive force is generated by a thermocouple having a contact point in the vicinity of the strain gauge in accordance with the temperature of the measurement object, and a voltage signal output from the bridge circuit changes in accordance with the thermoelectromotive force. At this time, since an AC power supply is used as the power supply for the bridge circuit, the change in the voltage signal corresponding to the distortion is caused by an AC component in the output voltage signal (specifically, in phase with the power supply voltage of the AC power supply). It appears as a change in the amplitude of the AC component. The change in the voltage signal according to the temperature appears as a change in the magnitude of the direct current component in the output voltage signal. In other words, the output voltage signal of the bridge circuit to which the power supply voltage is applied from the AC power supply is a combination of these AC components and DC components. Therefore, by detecting the alternating current component of the output voltage signal by the strain signal output means, it is possible to obtain a measurement value signal corresponding to the change in the resistance value of the strain gauge. Can be requested. Further, by detecting the direct current component of the output voltage signal by the temperature signal output means, it is possible to obtain a measurement value signal corresponding to the temperature change of the measurement object, and thereby the temperature of the measurement object. Can be requested. Therefore, a thermocouple can be formed with a lead wire connected to a strain gauge, and the strain and temperature of the measurement object can be measured simultaneously. As a result, even when the temperature changes during measurement, the strain of the measurement object can be easily measured. Can be obtained with high accuracy.

  In addition, the strain and temperature measuring device according to the third aspect of the present invention for solving the above-described problem forms a bridge circuit having four strain gauges attached to a measurement object on each side in accordance with the 4-gauge method. Of the four lead wires connected to the bridge circuit, the two lead wires for taking out the output voltage signal from the bridge circuit are made of different materials, so that the four strain gauges A measuring device for forming a thermocouple contact in the vicinity and obtaining strain and temperature of the measurement object from an output voltage signal of the bridge circuit, the AC power source being the power source of the bridge circuit, and the power source from the AC power source A strain signal output means for detecting an AC voltage component in the output voltage signal of the bridge circuit to which a voltage is applied, and outputting a signal corresponding to the strain of the measurement object from the detected AC voltage component; Detects a DC voltage component of the output voltage signal of the ridge circuit, to the DC voltage component the detected anda temperature signal output means for outputting a signal corresponding to the temperature of the measurement object.

  According to the strain and temperature measuring device of the third aspect, the bridge circuit having four strain gauges attached to the measurement object on each side is formed according to the 4-gauge method. That is, a bridge circuit having the four strain gauges on each side is formed. The bridge circuit includes two lead wires for applying a power supply voltage to the bridge circuit, and an output voltage from the bridge circuit. A total of four lead wires are connected to the two lead wires to be taken out. At this time, the two lead wires for taking out the output voltage from the bridge circuit are made of different materials, so that the vicinity of the four strain gauges (more specifically, the two lead wires made of different materials). The end portion on the strain gauge side (however, the strain gauge and wiring included between the end portions of the two lead wires are also included), and a thermocouple contact is formed.

  Then, according to the strain and temperature measuring device of the third aspect, the resistance value of the strain gauge changes according to the strain of the measurement object, similarly to the first and second aspects, and the resistance value The voltage signal output from the bridge circuit changes according to the change. Further, a thermoelectromotive force is generated by a thermocouple having a contact point in the vicinity of the strain gauge in accordance with the temperature of the measurement object, and a voltage signal output from the bridge circuit changes in accordance with the thermoelectromotive force. At this time, since an AC power supply is used as the power supply for the bridge circuit, the change in the voltage signal corresponding to the distortion is caused by an AC component in the output voltage signal (specifically, in phase with the power supply voltage of the AC power supply). It appears as a change in the amplitude of the AC component. The change in the voltage signal according to the temperature appears as a change in the magnitude of the direct current component in the output voltage signal. In other words, the output voltage signal of the bridge circuit to which the power supply voltage is applied from the AC power supply is a combination of these AC components and DC components. Therefore, by detecting the alternating current component of the output voltage signal by the strain signal output means, it is possible to obtain a measurement value signal corresponding to the change in the resistance value of the strain gauge. Can be requested. Further, by detecting the direct current component of the output voltage signal by the temperature signal output means, it is possible to obtain a measurement value signal corresponding to the temperature change of the measurement object, and thereby the temperature of the measurement object. Can be requested. Therefore, a thermocouple can be formed with a lead wire connected to a strain gauge, and the strain and temperature of the measurement object can be measured simultaneously. As a result, even when the temperature changes during measurement, the strain of the measurement object can be easily measured. Can be obtained with high accuracy.

  In addition, the physical quantity and temperature measuring device of the present invention for solving the above-described problems has four strain gauges attached to a strain generating body that generates strain according to the physical quantity of the measurement object on each side. To form a strain gauge type transducer having a bridge circuit formed according to the 4-gauge method, and to extract an output voltage signal from the bridge circuit among four lead wires connected to the strain gauge type transducer The two lead wires are made of different materials to form a thermocouple contact in the vicinity of the strain gauge transducer, and the physical quantity and temperature of the measurement object are obtained from the output voltage signal of the bridge circuit. An AC power source that is a power source of the bridge circuit, and an AC voltage component of the output voltage signal of the bridge circuit to which a power source voltage is applied from the AC power source, and the detected AC voltage component A strain signal output means for outputting a signal corresponding to the strain of the strain generating body, a DC voltage component of the output voltage signal of the bridge circuit is detected, and the temperature of the measurement object is detected from the detected DC voltage component. And a temperature signal output means for outputting a signal according to the above.

  According to the physical quantity and temperature measuring device, the bridge circuit is formed in accordance with the 4-gauge method, having four strain gauges attached to a strain generating body that generates strain according to the physical quantity of the measurement object, on each side. Forming a strain gauge transducer. That is, as in the third aspect, a bridge circuit having the four strain gauges on each side is formed, and the bridge circuit includes two lead wires for applying a power supply voltage to the bridge circuit. A total of four lead wires are connected to the two lead wires for taking out the output voltage from the bridge circuit. At this time, the two lead wires for taking out the output voltage from the bridge circuit are made of different materials, so that they are in the vicinity of the strain gauge transducer (more specifically, two lead wires made of different materials). The end portion on the strain gauge side (however, the strain gauge and wiring included between the end portions of the two lead wires are also included), and a thermocouple contact is formed.

  Further, according to the physical quantity and temperature measuring device, a strain is generated in the strain generating body of the strain gauge type transducer according to the physical quantity of the measurement object, and the resistance value of the strain gauge changes according to the strain, The voltage signal output from the bridge circuit changes according to the change in resistance value. Further, a thermoelectromotive force is generated by a thermocouple having a contact point in the vicinity of the strain gauge in accordance with the temperature of the measurement object, and a voltage signal output from the bridge circuit changes in accordance with the thermoelectromotive force. At this time, since an AC power supply is used as the power supply for the bridge circuit, the change in the voltage signal corresponding to the distortion is caused by an AC component in the output voltage signal (specifically, in phase with the power supply voltage of the AC power supply). It appears as a change in the amplitude of the AC component. The change in the voltage signal according to the temperature appears as a change in the magnitude of the direct current component in the output voltage signal. In other words, the output voltage signal of the bridge circuit to which the power supply voltage is applied from the AC power supply is a combination of these AC components and DC components. Therefore, by detecting the alternating current component of the output voltage signal by the strain signal output means, it is possible to obtain a measurement value signal corresponding to a change in the resistance value of the strain gauge, and thereby a strain gauge transducer. The physical quantity of the measurement object that causes the strain of the strain generating body can be obtained. Further, by detecting the direct current component of the output voltage signal by the temperature signal output means, it is possible to obtain a measurement value signal corresponding to the temperature change of the measurement object, and thereby the temperature of the measurement object. Can be requested. Therefore, a thermocouple can be formed from the lead wire connected to the strain gauge, and the strain and temperature of the strain-generating body of the strain gauge transducer can be measured simultaneously. As a result, even if the temperature changes during measurement, the strain The physical quantity of the measurement object that causes the strain of the strain generating body of the gauge transducer can be easily obtained with high accuracy.

  An embodiment of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a block diagram showing the overall configuration of the first embodiment of the strain and temperature measuring apparatus of the present invention, and FIG. 2 is a block diagram showing the overall configuration of a modification of the first embodiment of FIG. FIG. FIG. 3 is a block diagram showing the overall configuration of the second embodiment of the strain and temperature measuring apparatus of the present invention, and FIG. 4 shows the overall configuration of a modification of the second embodiment of FIG. FIG. FIG. 5 is a block diagram showing the overall configuration of the third embodiment of the strain and temperature measuring apparatus of the present invention. FIG. 6 is a block diagram showing the overall configuration of an embodiment of the physical quantity and temperature measuring apparatus of the present invention. Moreover, FIG. 7 is a graph for demonstrating the action | operation of the measuring apparatus of FIGS.

  First, a first embodiment of the present invention will be described with reference to FIG. The strain and temperature measuring device according to the present embodiment is a measuring device according to the first aspect of the present invention. In this embodiment, a bridge circuit having one strain gauge is formed according to a so-called 1-gauge 3-wire method. ing.

  Referring to FIG. 1, the strain and temperature measuring apparatus according to the present embodiment includes one resistive strain gauge 1 that causes a change in resistance value according to strain, and three strain wires 1 a to 2 c. And a measuring device 4 for transmitting and receiving a power supply voltage and an electric signal between a circuit housed in the bridge box 3 and a circuit housed in the bridge box 3. The bridge box 3 and the measuring device 4 may be configured integrally.

  The strain gauge 1 is affixed to an object to be measured (not shown), connected to the lead wire 2a through the connection portion 1a at one end, and lead wires 2b and 2c through the connection portion 1b at the other end. It is connected to the. The lead wires 2a and 2b are made of copper wire, the lead wire 2c is made of, for example, a constantan wire, and the set of lead wires 2a and 2c and the set of lead wires 2b and 2c form a thermocouple. The lead wires 2a and 2b may be constantan wires and the lead wire 2c may be a copper wire to form a thermocouple. Alternatively, one of the lead wires 2a and 2b may be a copper wire, the other may be a constantan wire, and the lead wire 2c may be a copper wire or a constantan wire to form a thermocouple. However, when there is a temperature change in the lead wires 2a and 2b during the strain measurement period, the resistance of the lead wires 2a and 2b changes. Therefore, in order to accurately measure the strain, the lead wires 2a and 2b It is desirable to use the same kind of material.

  The bridge box 3 is provided with connection terminals 3a to 3c for connecting the strain gauge 1 and the bridge box 3 in accordance with the 1 gauge 3 wire method, and the three lead wires 2a to 2c are connected to the connection terminals 3a to 3c. Each is connected to 3c. The bridge box 3 contains a resistance circuit formed by connecting three resistors 5, 5, and 5 having fixed resistance values in series. A strain gauge 1 and lead wires 2a and 2b are connected to the resistance circuit. By connecting them, the bridge circuit 7 including the strain gauge 1 on one side is configured. In this case, the resistance value of the resistor 5 is set to the same resistance value as the nominal resistance value of the strain gauge 1 (resistance value when no strain is generated).

  The bridge box 3 includes a pair of power input terminals 6a and 6b for applying a power supply voltage to the bridge circuit 7 from the outside (measuring instrument 4) and an output voltage signal of the bridge circuit 7 from the outside (measuring instrument 4). A pair of output terminals 6c and 6d are provided for output. The power input terminals 6a and 6b are connected to a pair of input portions 7a and 7b of the bridge circuit 7, respectively. The output terminal 6 c is connected to the output unit 7 c of the bridge circuit 7, and the output terminal 6 d is connected to the connection terminal 3 c of the bridge box 3. Supplementally, in the 1-gauge 3-wire method, the output portion 7 c and the connection portion 1 b of the strain gauge 1 are a pair of output portions of the bridge circuit 7.

  The measuring instrument 4 is provided with output terminals 4 a and 4 b for applying a power supply voltage to the bridge circuit 7 and input terminals 4 c and 4 d for inputting an output voltage signal of the bridge circuit 7. The output terminals 4a and 4b are connected to the power input terminals 6a and 6b of the bridge box 3, respectively. The input terminals 4c and 4d are connected to the output terminals 6c and 6d of the bridge box 3, respectively. The input terminals 4c and 4d are contacts (reference contacts) that serve as a reference for the temperature of the thermocouple formed by the set of lead wires 2a and 2c and the set of lead wires 2b and 2c, and have substantially the same temperature. It is provided as follows. The temperature of the measurement object (relative temperature with respect to the temperature of the reference junction) is detected as a thermoelectromotive force by a thermocouple formed by the set of lead wires 2a and 2c and the set of lead wires 2b and 2c.

  At this time, with respect to the connection line incorporated in the circuit in the bridge box 3 and the connection line connecting the bridge box 3 and the measuring instrument 4, the connection line from the connection terminal 3c to the input terminal 4d of the measuring instrument 4 is a lead wire. It is desirable to use the same type of connecting wire as 2c and the other connecting wires as the same type of connecting wires as the lead wires 2a and 2b. However, when the temperature in the bridge box 3 and the temperature between the bridge box 3 and the measuring instrument 4 are uniform, the connecting wire from the connecting terminal 3c to the input terminal 4d of the measuring instrument 4 is not always connected. The connection line of the same material as the wire 2c may be used, and the other connection line may not be the connection line of the same material as the lead wires 2a and 2b.

  The measuring instrument 4 includes an AC power supply 9 (hereinafter referred to as an AC bridge power supply) that applies an AC power supply voltage to the bridge circuit 7, and an AC amplifier circuit that amplifies the AC component of the output voltage signal of the bridge circuit 7. 10, a phase detection circuit 11 that detects a signal component corresponding to the resistance value of the strain gauge 1 from the output of the AC amplifier circuit 10, and a smoothing circuit 12 that smoothes the output signal of the phase detection circuit 11. . The measuring instrument 4 is provided with a DC amplifier circuit 13 for amplifying a DC component of the output voltage signal of the bridge circuit 7 and a smoothing circuit 14 for smoothing the output signal of the DC amplifier circuit 13. Further, the measuring device 4 detects the temperature of a temperature sensor 15 attached in the vicinity of the input terminals 4c and 4d and a contact (reference contact) serving as a reference of the temperature of the thermocouple based on the output of the temperature sensor 15. Using the output of the contact temperature detection unit 16 and the output of the contact temperature detection unit 16, the output signal of the smoothing circuit 14 is zero-contact compensated to obtain a signal at a level corresponding to the temperature (actual temperature) of the measurement object. And are provided.

  The output side of the AC bridge power supply 9 is connected to the pair of output terminals 4 a and 4 b of the measuring instrument 4, and applies the power supply voltage of the bridge circuit 7 between the pair of input portions 7 a and 7 b of the bridge circuit 7.

  The input side of the AC amplifier circuit 10 is connected to the pair of input terminals 4c and 4d of the measuring instrument 4, and the output voltage signal of the bridge circuit 7 is input. The AC amplifier circuit 10 extracts and amplifies an AC component in the output voltage signal of the bridge circuit 7 and outputs the amplified component to the phase detection circuit 11. The phase detection circuit 11 detects a signal component corresponding to the resistance value of the strain gauge 1 (an AC component having the same phase as the power supply voltage to the bridge circuit 7) from the output voltage signal of the AC amplifier circuit 10, and detects it. Full-wave rectification and output to the smoothing circuit 12. In general, the output voltage signal of the bridge circuit 7 includes a signal component (capacitance component) due to the influence of the capacitance of the lead wire of the bridge circuit 7 in addition to the signal component corresponding to the resistance value of the strain gauge 1. Since this capacitive component is a component having a phase different from that of the power supply voltage to the bridge circuit 7, the capacitive component is removed by detecting an alternating current component having the same phase as the power supply voltage to the bridge circuit 7. A signal component corresponding to the resistance value of can be obtained. Further, the smoothing circuit 12 smoothes the output (pulse flow) of the phase detection circuit 11 (converts the output (pulse flow) of the phase detection circuit 11 into a signal having a level corresponding to the average level), and smoothes the smoothing. This signal is output as a strain measurement signal indicating the strain value of the strain gauge 1 (the strain value of the measurement object to which the strain gauge 1 is attached).

  Similar to the AC amplifier circuit 10, the DC amplifier circuit 13 is connected at its input side to the input terminals 4 c and 4 d of the measuring instrument 4, and receives the output voltage signal of the bridge circuit 7. The DC amplifier circuit 13 extracts and amplifies the DC component of the output voltage signal of the bridge circuit 7 and outputs the amplified DC component to the smoothing circuit 14. Further, the smoothing circuit 14 smoothes the output of the DC amplification circuit 13 (converts the output of the DC amplification circuit 13 into a signal having a level corresponding to the average level), and measures the temperature of the measurement object (with respect to the temperature of the reference junction). Output as a signal according to (relative temperature).

  The combination of the AC amplifier circuit 10, the phase detection circuit 11, and the smoothing circuit 12 of the present embodiment corresponds to the distortion signal output means of the present invention, and the combination of the DC amplifier circuit 13 and the smoothing circuit 14 This corresponds to the temperature signal output means of the present invention.

  Next, the operation of the strain and temperature measurement device of this embodiment will be described with reference to the graphs shown in FIGS. 7A is a power supply voltage to the bridge circuit 7, FIG. 7B is an output voltage of the bridge circuit 7, FIG. 7C is an output voltage of the AC amplifier circuit 10, and FIG. 7D is a phase detection circuit. 7 (e) shows the output voltage of the smoothing circuit 12 (distortion measurement signal), and FIG. 7 (f) shows the signal waveform of the output voltage of the smoothing circuit 14 (signal according to the temperature of the measurement object). The horizontal axis represents time, and the vertical axis represents voltage.

  First, a power supply voltage is applied from the AC bridge power supply 9 to the bridge circuit 7. The power supply voltage to the bridge circuit 7 is a sine wave as illustrated in the graph of FIG.

  Next, the output voltage signal of the bridge circuit 7 is taken out from the connection terminal 3 c of the bridge box 3 and the output unit 7 c of the bridge circuit 7 and input to the AC amplifier circuit 10 and the DC amplifier circuit 13. The signal waveform of the output voltage of the bridge circuit 7 is as illustrated in the graph of FIG.

  At this time, when the measurement object is distorted, the resistance value of the strain gauge 1 changes according to the strain of the measurement object, and the output voltage signal of the bridge circuit 7 changes according to the change of the resistance value. . The change in the voltage signal corresponding to the distortion appears as a change in the amplitude of the AC component (specifically, the AC component in phase with the power supply voltage to the bridge circuit 7) in the output voltage signal of the bridge circuit 7. Further, a thermoelectromotive force is generated by a thermocouple having a contact point in the vicinity of the strain gauge 1 according to the temperature of the measurement object, and the output voltage signal of the bridge circuit 7 changes according to the thermoelectromotive force. The change in the voltage signal due to the thermoelectromotive force appears as a change in the magnitude of the direct current component in the output voltage signal of the bridge circuit 7. Therefore, the output voltage signal of the bridge circuit 7 includes the output voltage due to the strain of the strain gauge 1 (Vε in the graph of FIG. 7B) and the temperature of the strain gauge 1 (the measurement object to which the strain gauge 1 is attached). It includes the sum of the thermoelectromotive force (Vt in the graph of FIG. 7B) of the thermocouples 2a and 2c depending on the temperature.

  Next, the AC amplifier circuit 10 amplifies and outputs the AC component of the output voltage signal of the bridge circuit 7. The signal output from the AC amplifier circuit 10 is as illustrated in the graph of FIG.

  Next, the phase detection circuit 11 detects a signal component corresponding to the resistance value of the strain gauge 1 (an AC component having the same phase as the power supply voltage to the bridge circuit 7) from the signal output from the AC amplifier circuit 10, and It is full-wave rectified and output to the smoothing circuit 12. The signal output from the phase detection circuit 11 is as illustrated in the graph of FIG. In the example of the graph of FIG. 7D, it is assumed that there is no capacitance component described above for the sake of convenience.

  Next, the smoothing circuit 12 smoothes the output (pulse flow) of the phase detection circuit 11 (converts the output (pulse flow) of the phase detection circuit 11 into a signal having a level corresponding to the average level), and a strain gauge. 1 is output as a strain measurement signal indicating a strain value of 1 (a strain value of a measurement object to which the strain gauge 1 is attached). The signal output from the smoothing circuit 12 is as illustrated by the solid line graph in FIG. 7E, and the level (voltage value) corresponds to the strain value of the measurement object. The broken line graph in FIG. 7E shows the output of the phase detection circuit 11.

  Next, the direct current amplifier circuit 13 amplifies and outputs the direct current component of the output voltage signal of the bridge circuit 7. Next, the smoothing circuit 14 smoothes the output of the DC amplifying circuit 13 (converts the output of the DC amplifying circuit 13 into a signal of a level corresponding to the average level), and the smoothed signal is converted into the measurement object. A signal corresponding to the temperature (relative temperature with respect to the temperature of the reference junction) is output. The signal output from the smoothing circuit 14 is as illustrated in the solid line graph of FIG. 7F, and its level (voltage value) corresponds to the temperature of the measurement object. The broken line graph in FIG. 7F shows the output voltage signal of the bridge circuit 7.

  Next, the contact temperature detection unit 16 detects the temperature in the vicinity of the terminals 4c and 4d as the temperature of the contact (reference contact) serving as the reference of the thermocouple temperature, using the output from the temperature sensor 15. Next, the correction circuit 17 uses the temperature of the reference contact detected by the contact temperature detector 16 as a signal corresponding to the temperature of the measurement object output from the smoothing circuit 14 (relative temperature with respect to the temperature of the reference contact). Correct (zero contact compensation). Thereby, a signal having a level corresponding to the actual temperature of the measurement object is output.

  Through the above processing, the strain of the measurement object can be detected from the output (strain measurement signal) of the smoothing circuit 12. Further, the temperature of the measurement object can be detected from the output of the correction circuit 17 (a signal having a level corresponding to the actual temperature of the measurement object). Therefore, the strain and temperature measuring device of this embodiment can simultaneously measure the strain and temperature of the measurement object.

  Furthermore, using the detected temperature of the measurement object and the correction curve obtained in advance, the resistance value change of the strain gauge 1 according to the apparent strain (cause of the measurement object other than the strain (temperature of the measurement object)) The strain detected by this apparent strain can be corrected. As a result, the strain can be easily and accurately obtained even when the temperature changes during the measurement using the strain and temperature measuring device of the present embodiment.

  Next, a modification of the first embodiment of the present invention will be described with reference to FIG. In this modified example, only a location where a temperature sensor 15 and a contact point serving as a temperature reference of a thermocouple formed by disposing two lead wires out of the three lead wires 2a to 2c as mutually different materials are provided. Since this is different from the first embodiment of FIG. 1, the description of the same parts as those of the first embodiment of FIG. 1 is omitted.

  Referring to FIG. 2, in the strain and temperature measurement device of this modification, the contact point serving as a reference for the temperature of the thermocouple is set so that the connection terminals 3a, 3b, 3c of the bridge box 3 have substantially the same temperature. It is provided and configured. In particular, when the thermocouple is formed by using the lead wire 2a and the lead wire 2b as different materials, it is desirable to configure the contact serving as a reference for the temperature of the thermocouple in this way. In addition, when the contact which becomes the reference | standard of the temperature of a thermocouple is comprised in this way, the connection line integrated in the circuit in the bridge box 3 and the connection line which connects the bridge box 3 and the measuring device 4 are all copper wires. As good as The temperature sensor 15 is attached in the vicinity of the connection terminals 3a, 3b, and 3c, and the contact temperature detection unit 16 is a contact (reference contact) serving as a temperature reference of the thermocouple based on the output of the temperature sensor 15. Detect temperature. Other than this, the second embodiment is the same as the first embodiment shown in FIG.

  Accordingly, as in the first embodiment of FIG. 1, the AC component of the output voltage signal of the bridge circuit 7 can be extracted to determine the distortion of the measurement object. Further, the DC component of the output voltage signal of the bridge circuit 7 can be taken out and the temperature of the measurement object can be obtained. Thereby, the strain and temperature of the measurement object can be measured at the same time. As a result, even when the temperature changes during the measurement, the strain can be easily and accurately obtained.

  As a reference example of this embodiment, a bridge circuit having a strain gauge 1 is formed according to a so-called 1 gauge 2-wire method, and two lead wires connecting the strain gauge 1 to the bridge box 3 are made of different materials. A thermocouple may be formed. In this case, the lead wire 2c and the connection terminal 3c of the bridge box 3 are not provided, and the output terminal 6d of the bridge box 3 is connected to the end point of the resistance 5 of the bridge box 3 on the strain gauge 1 side. Other than this, the second embodiment is the same as the first embodiment shown in FIG. Therefore, as in the first embodiment of FIG. 1 or FIG. 2, the AC component of the output voltage signal of the bridge circuit 7 can be extracted to determine the distortion of the measurement object. Further, the DC component of the output voltage signal of the bridge circuit 7 can be taken out and the temperature of the measurement object can be obtained. Thereby, the strain and temperature of the measurement object can be measured at the same time. As a result, even when the temperature changes during the measurement, the strain can be easily and accurately obtained.

  Next, a second embodiment of the present invention will be described with reference to FIG. The strain and temperature measuring device of this embodiment is a measuring device according to the second aspect of the present invention. In this embodiment, a bridge circuit having two strain gauges is formed according to a so-called two-gauge method. . Note that this embodiment is different from the first embodiment only in the construction of the strain gauge incorporated in the bridge circuit, so the same reference numerals as those in the first embodiment are used for the same parts as in the first embodiment. The description is omitted using.

  Referring to FIG. 3, the strain and temperature measuring device of the present embodiment includes two resistance strain gauges 20 and 21 connected in series, and a strain gauge 20 and a strain gauge 20. 21 includes a bridge box 3 that connects 21 series circuits by three lead wires 22a to 22c, and a measuring instrument 4 that transmits and receives a power supply voltage and an electric signal between the circuits accommodated in the bridge box 3. Yes. The bridge box 3 and the measuring device 4 may be configured integrally.

  The two strain gauges 20 and 21 have the same gauge factor and nominal resistance value, and are attached to the front and back surfaces of a measurement object (not shown) by applying the 2-active method. The lead wire 22a is connected to the connecting portion 20a of the strain gauge 20 (one end of the series circuit of the strain gauges 20, 21), and the lead wire 22b is connected to the connecting portion 21b of the strain gauge 21 (the other end of the series circuit of the strain gauges 20, 21). The lead wire 22c is connected to the connection portion 20b of the strain gauge 20 and the connection portion 21a of the strain gauge 21 (more specifically, the midpoint of the series circuit of the strain gauges 20 and 21). The lead wires 22a and 22b are made of copper wire, the lead wire 22c is made of, for example, a constantan wire, and the set of lead wires 22a and 22c and the set of lead wires 22b and 22c form a thermocouple.

  The lead wires 22a and 22b may be constantan wires, and the lead wires 22c may be copper wires to form a thermocouple. Alternatively, one of the lead wires 22a and 22b may be a copper wire, the other may be a constantan wire, and the lead wire 22c may be a copper wire or a constantan wire to form a thermocouple. However, when there is a temperature change in the lead wires 22a and 22b during the strain measurement period, the resistance of the lead wires 22a and 22b changes. Therefore, in order to accurately measure the strain, the lead wires 22a and 22b It is desirable to use the same kind of material.

  The bridge box 3 is provided with connection terminals 3a to 3c for connecting the two strain gauges 20 and 21 and the bridge box 3 in accordance with the 2-gauge method, and the three lead wires 22a to 22c are connected to each other. The terminals 3a to 3c are connected respectively. The bridge box 3 contains a resistance circuit formed by connecting two resistors 5 and 5 having a fixed resistance value equal to the nominal resistance value of the strain gauges 20 and 21 in series. By connecting the strain gauges 20 and 21 via the lead wires 22a and 22b, a bridge circuit 7 including the strain gauges 20 and 21 on two adjacent sides is configured.

  The bridge box 3 has a pair of power input terminals 6a and 6b for applying the power supply voltage of the bridge circuit 7 from the outside (measuring instrument 4) and the output voltage signal of the bridge circuit 7 from the outside (measuring instrument 4). A pair of output terminals 6c and 6d are provided for output. The power input terminals 6a and 6b are connected to a pair of input portions 7a and 7b of the bridge circuit 7, respectively. The output terminal 6 c is connected to the output unit 7 c of the bridge circuit 7, and the output terminal 6 d is connected to the connection terminal 3 c of the bridge box 3. The connection between the bridge box 3 and the measuring instrument 4 and the configuration of the measuring instrument 4 are the same as in the first embodiment. Here, the input terminals 4c and 4d of the measuring instrument 4 are contacts (reference contacts) that serve as a reference for the temperature of the thermocouple formed by the set of lead wires 22a and 22c and the set of lead wires 22b and 22c. It is provided so that it may become the same temperature. The temperature of the measurement object (relative temperature with respect to the temperature of the reference junction) is detected as a thermoelectromotive force by a thermocouple formed by the set of lead wires 22a and 22c and the set of lead wires 22b and 22c.

  At this time, with respect to the connection line incorporated in the circuit in the bridge box 3 and the connection line connecting the bridge box 3 and the measuring instrument 4, the connection line from the connection terminal 3c to the input terminal 4d of the measuring instrument 4 is a lead wire. It is desirable to use the same kind of connection line as 22c and the other connection lines as the same kind of connection lines as the lead wires 22a and 22b. However, when the temperature in the bridge box 3 and the temperature between the bridge box 3 and the measuring instrument 4 are uniform, the connecting wire from the connecting terminal 3c to the input terminal 4d of the measuring instrument 4 is not always connected. The connecting wire of the same kind as that of the wire 22c may be used, and the other connecting wires may not be made of the same kind of material as that of the lead wires 22a and 22b.

  In this embodiment, the resistance values of the strain gauges 20 and 21 change according to the strain of the measurement object, and the amplitude of the AC component in the output voltage signal of the bridge circuit 7 changes according to the change in the resistance value. Change. Further, a thermoelectromotive force is generated by a thermocouple formed by the set of lead wires 22a and 22c and the set of lead wires 22b and 22c according to the temperature of the measurement object, and the bridge circuit 7 is generated according to the thermoelectromotive force. The magnitude of the direct current component of the output voltage signal changes. Therefore, the output voltage signal of the bridge circuit 7 is a combination of these AC components and DC components, and is as illustrated in the graph of FIG. 7B. Therefore, as in the first embodiment, the AC component of the output voltage signal of the bridge circuit 7 can be extracted to determine the distortion of the measurement object. Further, the DC component of the output voltage signal of the bridge circuit 7 can be taken out and the temperature of the measurement object can be obtained. Thereby, the strain and temperature of the measurement object can be measured at the same time. As a result, even when the temperature changes during the measurement, the strain can be easily and accurately obtained.

  Next, a modification of the second embodiment of the present invention will be described with reference to FIG. In the present modification, only a location where the temperature sensor 15 and the contact serving as the temperature reference of the thermocouple formed by disposing two of the three lead wires 22a to 22c as different materials are provided. 3 is different from the second embodiment of FIG. 3, and the description of the same parts as those of the second embodiment of FIG. 3 is omitted.

  Referring to FIG. 4, in the strain and temperature measuring device of this modification, the contact point serving as the temperature reference of the thermocouple is set so that the connection terminals 3a, 3b and 3c of the bridge box 3 have substantially the same temperature. It is provided and configured. In particular, when a thermocouple is formed using the lead wire 22a and the lead wire 22b as dissimilar materials, it is desirable to configure the contact serving as a reference for the temperature of the thermocouple in this way. In addition, when the contact which becomes the reference | standard of the temperature of a thermocouple is comprised in this way, the connection line integrated in the circuit in the bridge box 3 and the connection line which connects the bridge box 3 and the measuring device 4 are all copper wires. As good as Further, the temperature sensor 15 is attached in the vicinity of the connection terminals 3a, 3b, and 3c, and the contact temperature detection unit 16 detects the temperature of the contact (reference contact) that serves as a reference for the thermocouple temperature based on the output of the temperature sensor 15. Is detected. Other than this, the second embodiment is the same as the second embodiment of FIG.

  Therefore, as in the second embodiment of FIG. 3, the AC component of the output voltage signal of the bridge circuit 7 can be extracted to determine the distortion of the measurement object. Further, the DC component of the output voltage signal of the bridge circuit 7 can be taken out and the temperature of the measurement object can be obtained. Thereby, the strain and temperature of the measurement object can be measured at the same time. As a result, even when the temperature changes during the measurement, the strain can be easily and accurately obtained.

  As another embodiment of the second embodiment of FIG. 3 or FIG. 4, the active dummy method is applied, only the strain gauge 20 is attached to the measurement object, and the strain gauge 21 is the same as the measurement object. You may install so that distortion may not arise under environmental temperature. This is the same as the second embodiment of FIG. 3 or FIG. 4 except that only the resistance value of the strain gauge 20 changes according to the strain of the measurement object. Therefore, similarly to the second embodiment of FIG. 3 or FIG. 4, the AC component of the output voltage signal of the bridge circuit 7 can be extracted to determine the distortion of the measurement object. Further, the DC component of the output voltage signal of the bridge circuit 7 can be taken out and the temperature of the measurement object can be obtained. Thereby, the strain and temperature of the measurement object can be measured at the same time. As a result, even when the temperature changes during the measurement, the strain can be easily and accurately obtained.

  Next, a third embodiment of the present invention will be described with reference to FIG. The strain and temperature measuring device according to this embodiment is a measuring device according to the third aspect of the present invention. In this embodiment, a bridge circuit having four strain gauges is formed according to a so-called four-gauge method. . Note that this embodiment differs from the first embodiment only in the construction of the strain gauge incorporated in the bridge circuit and the instrument, so that the same parts as the first embodiment are the same as those in the first embodiment. The same reference numerals as those of the embodiment are used to omit the description.

  Referring to FIG. 5, the strain and temperature measurement device of this embodiment is a bridge formed by four resistance strain gauges 23 to 26 that cause a change in resistance value according to the strain, and the strain gauges 23 to 26. A measuring instrument 4 that transmits and receives power supply voltages and electrical signals to and from the circuit 7 via four lead wires 27a to 27d is provided. Unlike the first and second embodiments, the bridge box 3 is not interposed.

  The strain gauges 23 to 26 have the same gauge factor and nominal resistance value, each form a bridge circuit 7 as a resistor, and are attached to an object to be measured (not shown). The bridge circuit 7 is connected to a pair of output terminals 4a and 4b and a pair of input terminals 4c and 4d of the measuring instrument 4 by four lead wires 27a to 27d, respectively. The lead wires 27a to 27d are connected to the pair of input portions 7a and 7b and the pair of output portions 7c and 7d of the bridge circuit 7, respectively. The lead wires 27a to 27c are made of copper wire, the lead wire 27d is made of a constantan wire, for example, and the lead wires 27c and 27d form a thermocouple. The thermocouple may be formed by using the lead wire 27d as a copper wire and the lead wire 27c as a constantan wire. The configuration of the measuring instrument 4 is the same as that in the first embodiment.

  In this embodiment, the resistance value of the strain gauges 23 to 26 changes according to the strain of the measurement object, and the amplitude of the AC component of the output voltage signal of the bridge circuit 7 changes according to the change in the resistance value. To do. Further, a thermoelectromotive force is generated by the thermocouple formed from the lead wires 27c (copper wire) and 27d (constantan wire) according to the temperature of the measurement object, and the output of the bridge circuit 7 according to the thermoelectromotive force. The magnitude of the DC component of the voltage signal changes. Therefore, the output voltage signal of the bridge circuit 7 is a combination of these AC components and DC components, and is as illustrated in the graph of FIG. 7B. Therefore, as in the first and second embodiments, the AC component of the output voltage signal of the bridge circuit 7 can be taken out and the distortion of the measurement object can be obtained. Further, the DC voltage component of the output voltage signal of the bridge circuit 7 can be taken out and the temperature of the measurement object can be obtained. Thereby, the strain and temperature of the measurement object can be measured at the same time. As a result, even when the temperature changes during the measurement, the strain can be easily and accurately obtained.

  Next, an embodiment of the physical quantity and temperature measuring apparatus of the present invention will be described with reference to FIG. In the present embodiment, as in the third embodiment, a bridge circuit having four strain gauges is formed according to a so-called four gauge method. Note that this embodiment differs from the third embodiment only in that the strain gauge forms a strain gauge transducer, so the same parts as the third embodiment are described in the third embodiment. The same reference numerals are used to omit the description.

  With reference to FIG. 6, the strain and temperature measuring device of the present embodiment has four resistance strain gauges 23 to 26 and strain gauges 23 to 26 that cause resistance value changes corresponding to the strains. A measuring instrument 4 is provided for transmitting and receiving a power supply voltage and an electric signal between the strain generating body 28 and the bridge circuit 7 formed by the strain gauges 23 to 26 via four lead wires 27a to 27d. . As in the third embodiment, the bridge box 3 is not interposed.

  The four strain gauges 23 to 26 form a bridge circuit 7 and are attached to the strain generating body 28 to form a strain gauge transducer 29. At the time of measurement, the strain gauge transducer 29 is built in a housing (not shown), and a physical quantity (for example, load, acceleration, pressure, etc.) that the strain generating body 28 is to measure a measurement object (not shown). It is installed so that the distortion according to) may be generated. As in the third embodiment, the bridge circuit 7 is connected to a pair of output terminals 4a and 4b and a pair of input terminals 4c and 4d of the measuring instrument 4 by four lead wires 27a to 27d. The configuration of the measuring instrument 4 is the same as in the first to third embodiments.

  In the present embodiment, the strain of the strain generating body 28 is generated according to the physical quantity of the measurement object, and the resistance values of the strain gauges 23 to 26 are changed. The output voltage of the bridge circuit 7 is changed according to the change of the resistance value. The amplitude of the AC component of the signal changes. Further, a thermoelectromotive force is generated by a thermocouple formed from the lead wires 27c (copper wire) and 27d (constantan wire) according to the temperature of the measurement object, and the output of the bridge circuit 7 according to the thermoelectromotive force. The magnitude of the DC component of the voltage signal changes. Therefore, the output voltage signal of the bridge circuit 7 is a combination of these AC components and DC components, and is as illustrated in the graph of FIG. 7B. Therefore, as in the first to third embodiments, the AC component of the output voltage signal of the bridge circuit 7 of the strain gauge converter 29 is taken out, and the strain of the strain generating body 28 of the strain gauge converter 29 is calculated. The physical quantity of the measurement object to be generated can be obtained. Further, the DC component of the output voltage signal of the bridge circuit 7 of the gauge type converter 29 can be taken out and the temperature of the measurement object can be obtained. Thereby, the physical quantity causing the strain of the strain generating body 28 of the strain gauge transducer 29 and the temperature of the object to be measured can be measured simultaneously. As a result, even when the temperature changes during the measurement, the strain generating body. The physical quantity of the measurement object that causes 28 strains can be easily and accurately determined.

  The first and third embodiments of the strain and temperature measuring device of the present invention and the embodiment of the physical quantity and temperature measuring device of the present invention output a strain measurement signal and a signal at a level corresponding to the temperature. However, an A / D converter or a CPU may be mounted, and the distortion of the measurement object, or the physical value and the digital value of the temperature may be obtained and output from those output signals.

  Further, the first to third embodiments of the strain and temperature measuring device of the present invention and the embodiment of the physical quantity and temperature measuring device of the present invention are provided with a display means, and a level corresponding to the strain measurement signal and temperature. You may make it display the level value of this signal, the distortion | strain of a measuring object calculated from those signals, or the value of a physical quantity, and temperature. Further, a recording unit may be provided to record the strain measurement signal, the level value of the signal corresponding to the temperature, the strain of the measurement object calculated from these signals, or the physical quantity and temperature value. .

The block diagram which shows the whole structure of the measuring apparatus of the distortion and temperature in 1st Embodiment of this invention. The block diagram which shows the whole structure about the modification of 1st Embodiment of FIG. The block diagram which shows the whole structure of the measuring apparatus of the distortion and temperature in 2nd Embodiment of this invention. The block diagram which shows the whole structure about the modification of 2nd Embodiment of FIG. The block diagram which shows the whole structure of the measuring apparatus of the distortion and temperature in 3rd Embodiment of this invention. The block diagram which shows the whole structure of the measuring device of the physical quantity and temperature of this invention. The graph for demonstrating the action | operation of the measuring apparatus of FIGS.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... One strain gauge, 2a-2c ... Three lead wires, 7 ... Bridge circuit, 9 ... AC bridge power supply (AC power supply), 10 ... AC amplification circuit, 11 ... Phase detection circuit, 12 ... Smoothing circuit, DESCRIPTION OF SYMBOLS 13 ... DC amplifier circuit, 14 ... Smoothing circuit, 20, 21 ... Two strain gauges, 22a-22c ... Three lead wires, 23-26 ... Four strain gauges, 27a-27d ... Four lead wires 28 ... strain generating body, 29 ... strain gauge type transducer.

Claims (4)

A bridge circuit having one strain gauge attached to the object to be measured is formed according to the one-gauge three-wire method, and two lead wires out of the three lead wires connected to the one strain gauge are connected. A measuring device that forms a thermocouple contact in the vicinity of the strain gauge by using different materials from each other, and obtains the strain and temperature of the measurement object from the output voltage signal of the bridge circuit,
An AC power component that is a power source of the bridge circuit, and an AC voltage component of an output voltage signal of the bridge circuit to which a power source voltage is applied from the AC power source are detected, and distortion of the measurement object is detected from the detected AC voltage component. A distortion signal output means for outputting a signal corresponding to the output voltage, a DC voltage component of the output voltage signal of the bridge circuit is detected, and a signal corresponding to the temperature of the measurement object is output from the detected DC voltage component A strain and temperature measuring device comprising a temperature signal output means. A bridge circuit having two strain gauges connected in series, at least one of which is attached to the object to be measured, is formed according to a two-gauge method, and three leads connected to the series circuit of the two strain gauges Measurement of measuring the strain and temperature of the object to be measured from the output voltage signal of the bridge circuit by forming two thermocouple contacts in the vicinity of the strain gauge by making two lead wires out of different wires. A device,
An AC power component that is a power source of the bridge circuit, and an AC voltage component of an output voltage signal of the bridge circuit to which a power source voltage is applied from the AC power source are detected, and distortion of the measurement object is detected from the detected AC voltage component. A distortion signal output means for outputting a signal corresponding to the output voltage, a DC voltage component of the output voltage signal of the bridge circuit is detected, and a signal corresponding to the temperature of the measurement object is output from the detected DC voltage component A strain and temperature measuring device comprising a temperature signal output means. A bridge circuit having four strain gauges attached to the object to be measured on each side is formed according to a 4-gauge method, and an output voltage from the bridge circuit among four lead wires connected to the bridge circuit. Two lead wires for extracting signals are made of different materials from each other, so that a thermocouple contact is formed in the vicinity of the four strain gauges, and the strain of the measurement object is determined from the output voltage signal of the bridge circuit. And a measuring device for determining temperature,
An AC power component that is a power source of the bridge circuit, and an AC voltage component of an output voltage signal of the bridge circuit to which a power source voltage is applied from the AC power source are detected, and distortion of the measurement object is detected from the detected AC voltage component. A distortion signal output means for outputting a signal corresponding to the output voltage, a DC voltage component of the output voltage signal of the bridge circuit is detected, and a signal corresponding to the temperature of the measurement object is output from the detected DC voltage component A strain and temperature measuring device comprising a temperature signal output means. Forming a strain gauge transducer having a bridge circuit formed in accordance with the 4-gauge method, having four strain gauges attached to a strain generating body that generates strain corresponding to the physical quantity of the object to be measured. Of the four lead wires connected to the strain gauge type transducer, the two lead wires for taking out the output voltage signal from the bridge circuit are made of different materials, so that the strain gauge type conversion is performed. A measuring device for forming a thermocouple contact in the vicinity of a vessel and obtaining a physical quantity and temperature of the measurement object from an output voltage signal of the bridge circuit,
An AC power component that is a power source of the bridge circuit and an AC voltage component in an output voltage signal of the bridge circuit to which a power source voltage is applied from the AC power source are detected, and the distortion of the strain generating body is detected from the detected AC voltage component. A distortion signal output means for outputting a signal corresponding to the output voltage, and a DC voltage component of the output voltage signal of the bridge circuit is detected, and a signal corresponding to the temperature of the object to be measured is output from the detected DC voltage component A physical quantity and temperature measuring device comprising: a temperature signal output means.

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