JPH03209139A - Ultrasonic bolt axial tension measuring instrument - Google Patents

Abstract

PURPOSE:To measure the axial tension without error by measuring the variation of a time value to the bottom echo generated by applying the axial tension and moving a gate position to the position, where the bottom echo will be picked at the next measurement time, in accordance with the variation. CONSTITUTION:An axial tension calculation processing program 14b measures a bottom echo propagation time value Ts before tightening of a bolt 1 and stores it in a data storage area 14f through a time measuring circuit 8. When receiving a bottom echo propagation time value Ta after tightening of the bolt 1, the program 14b reads out the value Ts from the area 14f to calculate a variation DELTAt of the propagation time in accordance with DELTAt=Ta-Ts. Next, an axial tension F is calculated, and an axial tension Fa at the next measurement time is calculated in accordance with the axial tension F and is stored in the area 14f. A gate position update processing program 14c reads out the axial tension Fa from the area 14f to calculate a proper gate position Ln, and a gate position control signal to set the gate having a gate width W to the position corresponding to the distance Ln is outputted to a peak detecting and distance measuring part 7, and the gate position is changed to the distance Ln by the gate width W.

Description

[Detailed Description of the Invention] [Field of Application in Industry] This invention relates to an ultra-H wave bolt axial force measuring device. The present invention relates to an ultrasonic bolt axial force measuring device that can measure whether or not the axial force of a bolt is being applied without error during the work.

[Total/I using conventional technology ultra & wave! In the ultrasonic measurement and installation process that performs II, ultrasonic echoes are detected to determine the presence or absence of defects, the button distance (or position) to the defect, and the board thickness.

Furthermore, the axial force i111+ of the bolt (torque measurement) is also performed by utilizing the characteristics of such ultrasonic measurement.

It utilizes the fact that the propagation time of ultrasonic waves changes depending on the axial force of the bolt. For example, the received echo signal obtained from an ultrasonic probe (hereinafter referred to as probe) is displayed on a display screen. This is done by reading the slight change in position. Such measurements of the axial force of bolts are often performed when members are fastened at work sites where bolts are actually used for assembly and maintenance.

This kind of super? ]? When measuring bolt axial force using waves, the following method is used to reliably capture the echo to be measured (usually the bottom echo obtained from the tip of the bolt).

(1) Calculate the appropriate time position from the separately input bolt length information corresponding to the i'llll constant voltage, apply a gate to it, and receive the signal corresponding to the bottom echo E3 (see Figure 4). A method of extracting the echo signal, applying a threshold to it, measuring the peak position of the signal that exceeds the threshold, and measuring the time to the bottom of the bolt.

As shown in Figure 4 (a) and (b), the A scope image is shown in relation to the bolt 21, and the gate G is placed relatively wide so as to cover the time position of the bottom echo receiver No. 46. This is what you set. Note that El is the received echo signal of the four parts of the bolt, E2 is the received echo signal from the threaded end of its shaft, and E3 is the received echo signal of the bolt 2.
This is a received echo signal from the bottom surface corresponding to the tip end side of 1.

(2) Calculate the time position where false echoes are likely to occur from the bolt length information input separately corresponding to the measured bolt, mask that position, and measure the peak position of the signal that exceeds the threshold. method to measure the time to the bottom of the bolt.

This is because the mask M nullifies the received echo signal El from the neck region and the received echo signal E2 from the threaded end of the shaft, as shown in the A scope image in FIG. 4(b). It is set so that the received echo signal at the time position of the received signal E3 of the bottom echo is set to be effective.

[Problems to be solved] However, this method has the following drawbacks.

The above method (1) has an excellent function of extracting and measuring the specific echoes from among the miscellaneous echoes inside the bolt, but the axial force is applied to the bolt and the EI echoes are If the temporal position of the received echo signal E3 changes, the received echo signal E3 may deviate from the gate G. Also, gate G
If it is made wider, many other unnecessary signals will enter, resulting in more erroneous detections.

With method (2) above, measurements can be made even if the target echo position changes, but if the amplitude of the received echo signal changes due to poor coupling of the incident ultrasound, etc., an echo different from the target echo may be detected. It has the disadvantage of being measured. Also,
If a new echo appears due to a flaw occurring inside the bolt, especially on the bolt tip side beyond the mask M, if the echo of the flaw exceeds the threshold, the work D
There is a drawback that one signal is measured as the received echo signal E3. Note that many bolt defects appear as defects when axial force is generated when the bolt is tightened.

Therefore, when bolt tightening work is performed while measuring the bolt axial force at the site, there is a high probability that the measured value will be incorrect. Moreover, it requires skill to judge whether or not it is an error, and it is difficult for ordinary bolt tighteners to confirm whether or not there is an error while tightening the bolt and measure the axial force. It is easy to make mistakes when tightening bolts.

The purpose of this invention is to solve the problems of the prior art, and to provide an ultrasonic bolt shaft that can reduce axial force measurement errors during on-site bolt tightening work and almost eliminate bolt tightening errors. A force measuring device 1n will be provided.

[A Thousand Steps to Solve the Problem] The feature of the ultra-wave bolt axial force/Itll determining device of the first invention to achieve such an object is that the bottom surface obtained from the tip side of the bolt before bolt tightening is The change in the time value until the echo and the time value until the bottom echo in the bolt tightened state}d is calculated, and the axial force of the J & bolt is calculated based on this change, and the gate is adjusted according to the change I (t). The gate N+I is set to be larger than a moving mouse in which the bottom echo moves between a certain measurement point and the next measurement point in a normal bolt tightening state.

The second invention calculates the amount of change between the time value until the bottom echo obtained from the tip end of the bolt before bolt tightening and the time value until the bottom echo when the bolt is tightened, and based on this amount of change. The axial force of the bolt is calculated, and the gate is moved to the collection position of the bottom echo at the next measurement time based on the amount of change, and the gate width is set within the range for collecting the bottom echo at the next measurement time. It is something that

[Operation] In this way, the change in the time value until the bottom echo generated by applying an axial force is measured, and the bottom echo at the next measurement time is collected according to the product of this change. By moving the gate position at different positions, the bottom echo can be reliably extracted at the next measurement point even if the gate width is narrower than before. Therefore, only the bottom echo can be accurately collected without being affected by noise, defective echoes, etc., and axial force measurement with almost no errors is possible.

As a result, even if an amateur performs bolt tightening work while measuring the axial force at the site, the bolt sewing work can be performed in an appropriate manner without error, and bolt tightening errors in the bolt tightening work can be reduced.

[Example 1] Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

Figure 1 shows the ultrasonic bolt axial force i11 to which this invention is applied.
Figure 2 shows the relationship between the A scope image and the gate position when measuring the bolt, and Figure 3 is the flowchart of the axial force measurement process. be.

In FIG. 1, reference numeral 20 indicates ultrasonic bolt axial force measurement, and the ultrasonic deep wound part 6 to which the probe 4 is connected is 11 degrees. As shown in the figure, the probe 4 has a bolt to be measured (hereinafter referred to as a bolt) 1 which is attached to the members 2 and 3 to be tightened and fastened.
It is attached to the head of ``l''I.

The ultrasonic deep wound section 6 sends out a 5-pulse signal to the probe 4, and receives an ultra 8-wave echo reception signal (reception echo signal). This is a measurement unit that has a built-in so-called pulser receiver (the receiver includes an amplifier and a detection circuit), and it amplifies or attenuates the received echo signal and detects it. An image signal is generated and sent to the peak detection path M1 constant section 7.

Peak Detection ● The path measuring unit 7 detects the waveform of the received echo signal obtained by the ultrasonic deep wound part 6 and the probe 4.
The waveform of the received echo signal is extracted at the set gate portion, its peak value is detected, the time to the detected peak is measured, and the time value (corresponding to the path) is sent to the measurement data processing device 16. Note that the time measurement data (time scale) in this case is obtained in the form of a digital value from the counter of the time measurement circuit 8 provided inside the peak detection path measurement section 7, and is output as is.

Peak detection●The gate set by the path measuring section 7 is
It is provided to extract the bottom surface reception echo signal E3 from the tip end side of the bolt 1, is set corresponding to the bottom surface echo signal E3, and is sequentially moved in accordance with the measurement. This movement is controlled by the measurement data processing device 16 depending on the bolt tightening state.

The measurement data processing device 16 includes a microprocessor (hereinafter referred to as CPU) 9, a keyboard (or operation panel, hereinafter referred to as keyboard) 10, an interface 12, and an image memory 13.
, a main memory 14, and an LCI (liquid crystal) display 15, which are connected to the phase -fj by a bus 11. Further, the TFJ 5 self-peak detection unit 7 and the ultrasonic flaw detection unit 6 are also connected to the bus 11 via the interface l2,
It is controlled by CPU9.

CPU9 performs peak detection●path/! 1. Receives the measurement data of the time set from the time measuring circuit 8 to the generation of the bottom echo, and stores the data in the main memory 14.
l. The processing Pl!, which will be described later, is performed on this data according to various processing programs stored in the memory. is executed, the result is recorded in the image memo IJ13, and the measured result is displayed on the display 15.

Here, the main memory l4 stores a bottom position gate setting program 14a, an axial force calculation processing program 14b1, a gate position update processing program 14C, an axial force determination processing program 14d1, a measured data display processing program 14e, etc. The storage area 14f stores the time measurement value (before bolt tightening) for the bolt to be measured.
data such as travel distance) etc. are stored.

Figure 2 shows an example of a received echo signal obtained in the ultrasonic detection section 6 in response to an echo received by the probe 4. The received echo signal El% of the four parts of the bolt 1 is the received echo signal SJ'E2 from the end of the screw part, the bottom received echo signal E3, and the echo signal E3 is reflected from multiple points inside the bolt 1 and is emitted.
When a delayed reception echo signal Ed, etc. is received, and in addition to these, there is a defect Kf inside the bolt 1,
A reception echo signal Ef of the defect is received corresponding to the position.

Furthermore, when the bolt 1 is tightened and its axial force increases, the ultrasonic propagation time to the bottom surface increases, so the position of the bottom surface received echo signal E3 gradually retreats from the position shown in the figure to the rear as shown by the dotted line. go.

In the figure, G is a gate, and the position of the first gate G for extracting the bottom echo-E3 is calculated by the bottom iT1i position gate setting program 14a according to the total length of the bolt (or dimensions including its diameter). However, the subsequent gate position is determined according to the movement of the bottom echo (κ of increased propagation time) or the axial force at that time.

In addition, the total length of bolt 1 (or including its diameter, J′l)
is input from the keyboard 10. Note that when the diameter is set approximately, only the entire length is required for Ri 1.

Therefore, the gate G can be set in either of the following two ways -
・Someone will be hired and transferred.

■A method that follows and moves according to the amount of movement of the bottom echo based on before tightening. In this case, the gate width is selected so that the range is larger than the range in which the bottom echo moves between a certain A1 fixed point and the next measurement point under normal bolt tightening conditions, and Game H61
selected smaller.

■The amount of movement of the measured current axial force or the bottom echo (the amount of movement of the bottom echo at the time of measurement based on before tightening, or the movement of the bottom echo between a certain measurement point and the next measurement Tht
) to calculate the next gate position and set the gate. In this case, the gate can be further made smaller, and the width can be narrowed to the extent that the bottom echo can be extracted.

Now, the position of the first gate is determined by the following formula based on the total length of the bolt, which was manually applied in advance.

GS=L*2/VO ・・・・・・・・・■However, GS is gate {1°7. if'Z (center position of game 1), L is the total length of the manually-built bolt? A V o is the current sound velocity of the bolt material (input or internally calculated depending on the temperature at that time). Note that the width of the gate G is initially calculated by extracting the bottom echo of the tightening operation + fif and the bottom echo when the tightening operation starts (moving further backward than before tightening), as shown in Figure 2. The width has been selected as wide as possible.

By the way, when an axial force is applied to the bolt l, the propagation time of the echo signal reflected at each part of the bolt l is related to the generated axial force and the dimensions of each part, and increases accordingly. Therefore, by setting the amount of increase in the propagation time of the bottom echo of the bolt to 7!1, the axial force applied to bolt 1 is calculated, and based on the calculated bolt axial force of the current flower, the next measurement point is determined. The amount of change in the echo propagation time can be found by

Specifically, by calculating the bolt axial force IJjL using the formula (■) and predicting the bolt axial force at the next fixed point in time, and by knowing the position where the next echo will occur using the formula (■), the next gate setting position can be determined. can be resolved quickly.

Where, F: bolt axial force, Δt: change in bolt bottom echo propagation time Fi (difference in propagation time between before and after tightening), δ: bolt conformance, and K: material constant according to the following formula.

However, L: total length of bolt, A: effective shear volume of bolt, E
: Young middle school.

Therefore, the position Ln of the gate to be set next is: where Ln is the distance from the bottom of the bolt d at the measured position, and Fa is the axial force predicted at the next measurement point.

If the axial force Fa at the next measurement point can be calculated, the next gate setting position can be calculated from this equation (2).

On the other hand, if the current axial force F is known, the axial force Fa at the next measurement point in normal tightening work can be calculated according to the diameter and length of the bolt. The generation position of the bottom echo E3 and the gate width W for extracting the bottom echo E3 can be set. In addition, in this case, gate support W
is selected so that it has a width that includes errors before and after the next bottom surface E3 occurrence position correction. This is the method (2) of this invention mentioned above.

In addition, the gate width W is 1 in the normal bolt tightening state.
If the difference in bottom echo propagation time between the previous measurement point and the next measurement point is set to be larger than ΔT = Δtn - Δtn - 1 (where n is the number of repeated measurements), +11 will be increased by this ΔT. Simply moving the gate moves the gate position by the amount of shift, so bottom echoes can always be extracted.

Moreover, this movement of ΔT may be determined by determining the gate setting position according to Δt, assuming that the initial position before tightening is the star reference. This is the method (2) of this invention mentioned above.

Therefore, if the gate is set using any of the above methods, the gate width can be made narrower than the conventional gate width, and only the bottom echo E3 can be extracted without including noise or defects in front of the bottom surface. And, this gate width W is compared to the diameter and overall length of the bolt,
It can be set in advance by determining it experimentally.

By the way, in the case of adopting the method ■, the next base + fr
The axial force Fa at the next measurement point, which serves as a reference for calculating the generation position of the i-echo E3, is determined according to a predetermined function, and by determining this, the gate position can also be determined using formula (2), but the data storage area 14f The amount of gate movement (corresponding to the above-mentioned Δt) and gate width W may be stored in a table as a function of the current axial force F in accordance with the diameter and overall length of the bolt. The gate width W and the amount of movement in this case can be easily obtained by experimentally determining. Further, the gate 1tW may be a fixed value determined by the bolt diameter and the overall length.

Therefore, first, in starting the axial force measurement, the axial force calculation processing program 14b calculates the bottom echo propagation time value of bolt tightening + 1if of bolt 1 (this may also be done by measuring the reference bolt corresponding to bolt 1). Ts (second
(see figure) is received from the time measurement circuit 8 and stored in the data storage area 14f.

Next, when entering the measurement state, the axial force calculation processing program 14b receives the bottom echo propagation time value Ta (see FIG. 2) in the bolt tightening state of the time measurement circuit 8, and calculates the value in the data storage area 14f. to the above-mentioned propagation time WTs
is read out, and the change amount Δt, which is the bolt bottom echo propagation time difference, is calculated by Δt=Ta−Ts to calculate the change in propagation time. Next, the axial force F is calculated according to the equations (2) and (2), and in the method (2) above, the axial force Fa at the next measurement time is obtained and stored in the data storage area 14f.

The gate position history new processing program 14c is started by the axial force calculation processing program 14b, and in the method (■), the axial force calculation processing f1K! The axial force Fa at the next measurement point calculated by the program 14b is read out from the data storage area 14f, and based on this, an appropriate gate position Ln is calculated according to the formula 11
A gate f1 position control signal to be set at a position corresponding to Ln is output to the peak detection ●path length 7lllll constant section 7. As a result, the gate G has a gate width W of R/. i;'l
It was changed to IJI L n. Further, in this case, in the method (2), the gate position is updated by ΔT based on ΔT (=Δt n - t n -l) or Δt obtained at the time of measurement.

From now on, in the same way, each time for the next measurement, either update the gate width W as a constant according to the change in the current axial force F, or update it by ΔT, or change it corresponding to the axial force each time. By selecting the gate position and gate width according to the current measurement end T, in order to accurately extract the bottom echo at the next measurement point.
At this point, the gate is set to move in advance. In this case, the amount of movement of the gate ΔL=Ln−L is calculated and ΔL
The gate position may be corrected by Furthermore, if the gate position and gate width are tabulated as corresponding to the current axial force F, the settings may be made with reference to that table.

In this way, if the gate position is moved to an appropriate position following the bottom echo generation position, there is no need to provide a lot of room for the gate, and the gate cap can be made as wide as possible. can.

Therefore, only the received echo signal of the bottom surface echo can be accurately extracted without being affected by noise, adjacent defects, etc., and the axial force can be measured accurately.

On the other hand, the determination of the axial force is performed by the axial force determination program 14d, and this program is activated by the gate position update program 14c. The axial force is determined by comparing the axial force F calculated by the axial force calculation processing program 14b with the axial force Fs that is the appropriate axial force stored in advance in the data storage area, which is W9. By determining whether or not. As a result, when the axial force F is less than the axial force Fs, a flag indicating completion of tightening is stored in the data storage area 14f. Then, the measurement data display processing program 14e is activated next.

The measurement data display processing program 14e reads out the axial force F stored in the data storage area 14f and the flag indicating whether it is an appropriate value, transfers it to the image memory 13, and displays the bolt axial force and its value. Processing is performed to display whether or not the goal A1 has been reached on the display l5. After this display processing, the axial force calculation process 1J! Start program 14b. As a result, a similar bolt axial force measurement is then performed corresponding to the measurement period (every time a transmitted pulse is applied to the probe 4) or an integer multiple of the measurement period, and then the axial force is determined and measured. Whether the IE is suitable or not is displayed sequentially.

Next, the overall measurement operation will be explained according to the processing flowchart shown in FIG.

In step (3) in FIG. 3, the bolt dimensions (total length or total length and diameter) are entered manually from the keyboard 10. In the next step (2), upon receiving this input information, the bottom position gate setting program 14a is activated, and a gate is set at the time position of the bottom echo.

In the next step ■, II! up to the bottom surface before tightening the bolts! It is determined whether or not one-question value measurement is to be performed using a function key input in advance. When calculating the time to the bottom echo before tightening the bolt, in step 2, measure the time value of the bottom E3 for the bolt 1 that is not attached to the member (or before the bolt is tightened). conduct,
Store it in memory. Further, when the measurement is not performed before bolt tightening, the waiting loop is entered.

In the next step, Step No. 2, it is determined whether or not to measure the axial force when the bolt is tightened. This determination is also made based on the function keys input from the keyboard 10. When other keys are manually operated and it is determined that the bolt axial force is not being measured,
Depending on the manual key, the process either goes into a waiting loop, ends the process, or moves on to another raccoon. Note that if you end the process here or move to another process, the next time the function key corresponding to the measurement of bolt tightening condition is input from the keyboard 10, step ■ of this determination process will be executed. Karadokoro 11! is started.

As a result of the determination in step (2), if the axial force is to be measured in the bolt tightened state, the axial force calculation processing program 14b is activated in step (2), and the variable 1ttΔt and the axial force F are calculated. J! New location pI! Program 1
4c is activated, and the gate position is set to an appropriate position according to method (1) or (2).

Then, in the next step (2), the axial force determination processing program 14d is started, and the calculated axial force F is determined by the prefecture I'? ! {
A determination is made as to whether it is less than or equal to IFs, and each result is stored in memory.

In step (2), a process for displaying the measurement results stored in the memory is performed, and in step (2), it is determined whether or not the measurement process is completed depending on whether or not the end key is manually pressed. and,
If the measurement process is not completed, the process returns to step (2) and similar measurements are repeated.

As explained above, Il! from the peak position to the bottom echo! To measure the value between f (path length), the received echo signal itself obtained from the ultrasonic flaw detection section 6 is A/D converted and sampled, the discrete digital value is stored in memory, and the CPU converts it into data. It can also be obtained by processing 111. The gate settings in this case can be easily set by performing data processing using an arithmetic processor. Therefore, the present invention is not limited to the one in which the peak detection/path measurement unit 7 as shown in the embodiment is provided to perform gate setting and measurement.

[Effects of the Invention] As described above, in this invention, the amount of change in the time value until the bottom echo generated by applying an axial force is measured, and the bottom echo at the next measurement point is determined according to this amount of change. If you move the gate position to the position where you want to collect the
Even if Ill is made narrower than before, the bottom echo can be reliably extracted at the next measurement point. Therefore, only the bottom echo can be accurately collected without being affected by noise, defective echoes, etc., and axial force measurement with almost no errors is possible.

As a result, even if an amateur performs bolt tightening work while measuring the axial force at the site, the bolt tightening work can be performed properly without errors, and bolt tightening errors in the bolt tightening work can be reduced.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an ultrasonic bolt axial force measuring device to which the present invention is applied, and FIG. 2 is an explanatory diagram showing the relationship between the A scope image and the gate position when measuring the bolt.
FIG. 3 is a flowchart of the axial force measurement process, and FIG. 4 is an explanatory diagram showing the relationship between the conventional A scope image and the gate position when measuring a bolt. 1... Bolt to be measured, 2.3... Member to be tightened, 4... Ultrasonic probe, 6... Ultrasonic flaw detection section, 7... Peak detection ● Path Measuring part, 8a...
・A/D conversion circuit, 8b... Time measurement circuit, 9...
Microprocessor (CPU), 10... Keyboard, 11... Bus, 13... Image memory, 14...
Main memory, 14a... Bottom position gate setting program, 14b... Axial force calculation processing program, 14c.
...Gate position update processing program, 14d... Axial force determination processing program, 14e... Measured data display processing program, 14f... Data storage area, 16... Measured data processing device. Patent creator Kyushu Electric Power Co., Ltd. Himori Construction Machinery Co., Ltd.

Claims (5)

[Claims] (1) Calculate the amount of change between the time value until the bottom echo obtained from the tip end of the bolt before bolt tightening and the time value until the bottom echo when the bolt is tightened, and calculate the axial force of the bolt based on this amount of change. The gate width is calculated and moves the gate in accordance with the amount of change, and the gate width is the amount of movement of the bottom echo between a certain measurement point and the next measurement point in a normal bolt tightening state. An ultrasonic bolt axial force measuring device characterized by a larger setting. (2) Calculate the amount of change between the time value until the bottom echo obtained from the tip of the bolt before bolt tightening and the time value until the bottom echo when the bolt is tightened, and calculate the axial force of the bolt based on this amount of change. At the same time as calculating, a gate is moved to a collection position of the bottom echo at the next measurement time based on the amount of change, and the gate width is set to a range for collecting the bottom echo at the next measurement time. An ultrasonic bolt axial force measuring device characterized by: (3) Calculate the amount of change between the time value until the bottom echo obtained from the tip of the bolt before bolt tightening and the time value until the bottom echo when the bolt is tightened, and calculate the axial force of the bolt based on this amount of change. At the same time, the amount of change in the time value up to the bottom echo between the previous measurement point and the current measurement point is obtained, and the collection position of the bottom echo at the next measurement point is calculated and the position is set at that position. move the gate,
An ultrasonic bolt axial force measuring device characterized in that the gate width is set within a range for collecting the bottom echo. (4) The next bottom echo collection position is calculated according to the calculated axial force, and a gate is set there, and the gate width is a width that includes the generated error with respect to the bottom echo collection position. The ultrasonic bolt axial force measuring device according to claim 2 or 3, characterized in that: (5) The gate is set by obtaining a gate movement amount determined as a normal tightening amount and a gate width corresponding to a width for extracting a bottom echo according to the calculated axial force. The ultrasonic bolt axial force measuring device described.