JPH01281879A - Torque checking method for torque wrench and torque checker device for torque wrench - Google Patents

Abstract

PURPOSE:To eliminate the error in measuring a torque caused by the irregularity of the movement state of a torque wrench by providing the waveform integral part detecting the impact torque generated intermittently by converting it into a voltage signal and converting the voltage signal into the voltage level between both polarities of a condenser by integrating each impact torque by the condensed action of a condenser. CONSTITUTION:The impact torque generated intermittently according to the fastening operation of a torque wrench is converted into a voltage signal by a transducer 1. The respective impact torque in a certain time is then integrated by the condensed action of the condenser at a waveform integral part 5 and the voltage signal from the transducer 1 is converted into the voltage level of between both polarities of the condenser. The integral torque value is compared with a reference torque value by a comparison part 12 based on this voltage level and a pass deciding signal is output. The pass of a wrench capacity is displayed by a display part 13 based on this pass deciding signal. As a result, the measuring error of a torque caused on the irregularity of the movement state of a torque wrench different on each stroke can be eliminated and the fastening capacity can correctly be assesed.

Description

Detailed Description of the Invention (Field of Industrial Application) This invention relates to a torque check method for torque wrenches, including impact wrenches, pulse wrenches, etc. used in tightening work, and a torque checker device for torque wrenches. The present invention relates to a torque check method and a torque checker device that improve the accuracy of determining the degree of decline in practical performance of a torque wrench and determining the pass/fail of tightening performance.

(Prior art) A specific example of a conventional torque checker is disclosed in Japanese Patent Application Laid-Open No. 55-117.
Known for No. 69. In this conventional example, a torque sensor (torque transducer) with a strain gauge attached is attached to the socket of an impact wrench, reads the highest value of the electrical output signal from the strain gauge, and compares it with a preset reference torque. A controller is provided to do this. In the conventional device as described above, the torque wrench is operated for a certain period of time, and during that time, the impact torque value caused by the repeated impact of the hammer mechanism of the torque wrench is detected as an electric signal by the strain gauge of the torque sensor, The controller has a function of reading only the highest value and comparing the read value with the reference torque to determine the degree of decrease in the tightening ability of the torque wrench and whether the tightening ability is acceptable or not.

(Problems to be Solved by the Invention) However, in the torque checker as described above, there is room for improvement in torque measurement accuracy due to the characteristics of the hammer mechanism of the impact wrench, which will be described later. That is, the motion state of the hammer mechanism of the impact wrench during rotation is very complex and irregular. For example, at the moment when the hammer collides with the anvil, the relative phase, rotation speed, repulsion rotation angle, etc. between the parts that make up the hammer mechanism, etc.
- It differs for each blow and is not a fixed condition.

For this reason, not only does the hammer mechanism exhibit complex characteristics in that the amount of torque generated differs with each stroke, but as the hammer mechanism's striking portion progresses to wear and deterioration, the regularity of the strikes becomes disrupted, causing The variation in torque at each time also increases further. Therefore, conventional torque checkers that only read the maximum value of the impact torque associated with the impact of the hammer mechanism, that is, the peak torque, cannot accurately detect the decrease in the tightening ability of impact wrenches that have irregular characteristics as described above. It cannot be measured. In other words, wrench ability is
It is evaluated based on how much tightening force can be applied to the screw per unit time, and the number of strokes per unit time,
This is because it is thought to be determined by the magnitude and generation time of each impact force. In addition, since the torque value measured with conventional equipment is the shocking maximum torque value that occurred within the measurement time, this measurement value can be used to accurately evaluate the average tightening ability when the torque wrench is actually used. I can't.

This invention was made in order to solve the above-mentioned conventional problems, and its purpose is to improve the degree of reduction in the tightening ability of a torque wrench and the accuracy of determining whether the tightening ability is acceptable or not. An object of the present invention is to provide a torque check method and a torque checker device for a torque wrench.

(Means for Solving the Problem) Therefore, the torque check method for a torque wrench of the present invention converts the impact torque that occurs intermittently as the torque wrench tightens into a voltage signal proportional to the torque value. This voltage signal is used to integrate each impact torque within a certain period of time using the capacitor's charge storage function, and the integrated torque value based on the voltage level between the electrodes of the capacitor is compared with a preset reference value. I try to understand the tightening capacity of torque wrenches.

Next, as shown in FIG. 1, the torque checker device for a torque wrench of the present invention has a transformer that converts the impact torque that is intermittently generated as the torque wrench tightens into a voltage signal proportional to the torque value. A transducer is provided, and a waveform integrator is provided which integrates the voltage signal from the transducer and converts it into a voltage level between the two poles of the capacitor by integrating each shock torque within a certain period of time by the power storage action of the capacitor. an output value comparison section that compares the integrated torque value based on the voltage level of the voltage with a preset reference torque value and outputs a pass/fail determination signal, and a pass/fail display section that displays pass/fail of the wrench ability based on the pass/fail determination signal. has been established.

(Function) According to the torque check method for a torque wrench and the torque checker device for carrying out the method according to the present invention, since the impact torque for each impact within a certain period of time is integrated by means of electricity storage, the capacitor after electricity storage is The voltage level is a value that has the same meaning as the cumulative tightening capacity of the torque wrench within a certain period of time, and this is read and compared with a preset reference value to determine if the torque wrench's capacity has decreased or if the wrench is Perform pass/fail judgments on abilities.

Therefore, by eliminating the measurement error caused by the irregularity of the torque wrench's motion state, which varies with each stroke, it is possible to calculate the time required for actual tightening work, rather than the peak torque for each stroke, which has large fluctuations. The tightening ability of a torque wrench can be accurately evaluated as the average ability accumulated over time.

In addition, the pass/fail indicator displays whether or not the tightening torque complies with the preset reference torque, allowing you to determine at a glance whether the wrench ability is pass or fail, improving the reliability of test work. .

(Example) Next, a torque checker device for a torque wrench of the present invention will be described in detail with reference to the drawings, taking a torque checker device for an impact wrench as an example.

First, FIG. 1 shows a block diagram of the impact wrench torque checker device, and in this FIG.
1 is a torque transducer attached to the socket of an impact wrench.

This transducer 1 has a function as a torque sensor, converts the striking force of each strike of the impact wrench into an electric signal, that is, a pulse voltage signal 2, and supplies the pulse voltage signal 2 to the torque checker 3. There is. For example, TT-20 manufactured by Fuji Aircraft Co., Ltd., which has a structure that does not easily vibrate when struck by a transducer or an impact wrench.
I am using the TT-150 model.

The torque checker 3 receives the input pulse voltage signal 2.
Based on this, as will be described in detail later, the measurement value of the tightening torque using an impact wrench is displayed as a digital value, and it is also configured to display whether or not the tightening work was performed as specified.

The block configuration of this torque checker 3 is a signal amplification section 4, a waveform integration section 5, a hold section 6, a digital display section 7,
Stable power supply section for transducer 8, measurement time setting section 9
, a power supply section 10, a lower limit value setting section 11, an output value comparison section 12, and a GO2NG display section 13.

First, AC power is input to the power supply unit 10 to supply power to each block. Note that the power supply section 10
By incorporating a secondary battery into the device, it becomes possible to carry out measurements while moving, even outdoors where there is no AC power source. The transducer stable power supply unit 8 supplies a stable power supply voltage to the transducer 1, and maintains the torque voltage conversion accuracy of the transducer 1 well.

Since the pulse voltage signal 2 from the transducer 1 is very weak, the signal amplification section 4 has a function to amplify the pulse voltage signal 2 so as to facilitate signal processing when relocated after the waveform integration section 5. have.

The output signal 14 from the signal amplification section 4 is input to the waveform integration section 5 and the measurement time setting section 9. The waveform integrator 5 converts the intermittent pulse voltage signal 2 from the transducer 1, which is output only at the moment the hammer mechanism of the impact wrench strikes, into an integrated voltage waveform. The measurement time setting unit 9 also has a function of starting time counting from the time when the batting starts, and outputting a time-up signal 15 when a preset time is reached.

Here, the circuit configuration of the waveform integrator 5 will be explained with reference to FIG.

In FIG. 2, the waveform integrator 5 is connected to the backflow prevention rectifier circuit 1.
6, a resistor R, and a capacitor C. Furthermore, the rectifier circuit 16 includes a backflow prevention diode 17 and an operational amplifier 18 for correcting loss in the diode 17.
It has The pulse voltage signal 2 from the transducer 1 is input to the positive terminal of the operational amplifier 18,
A feedback signal from the diode 17 is input to the negative terminal, and the pulse voltage signal 2 is amplified and corrected by an amount corresponding to the amount of attenuation of the feedback signal by an operational amplifier. At this time, the waveform of the pulse voltage signal 2 input to the operational amplifier 18 is an intermittent waveform 19 caused by the collision between the hammer and anvil of the hammer mechanism, as shown on the left side of FIG. When this waveform 19 is applied to the resistor R and capacitor C through the rectifier circuit 16, the output voltage between the two poles of the capacitor C is converted into a continuous waveform 20 on the right side of FIG.

The state of this conversion is illustrated in FIG. 3 for one blow. The waveform 21 shown by the solid line in FIG. 3 represents the characteristics of only one stroke of the impact wrench, t is the duration of the output of one stroke, and VB is the stage before the waveform integration section 5, that is, the signal amplification section 4. This is the voltage corresponding to the striking force in (Fig. 1). On the other hand, the waveform 22 shown by the broken line represents the voltage characteristics between the two poles of the capacitor C, where ν8 is the voltage before the impact pulse is input, and VC is the voltage after the impact pulse is applied manually. . The relationship between each of the above voltages and one blow time is as follows.

VC= (VB-VA) X (1-e-”cR) +
VA-...(1) In this equation (1), C is the capacitance of the capacitor C, and R is the resistance value of the resistor R. From equation (1), the larger the difference between voltages VA and VB, the more voltage VC during the time period.
It can be seen that the change in voltage VC becomes larger, and the longer time t becomes, the larger the change in voltage VC becomes.

The above waveforms for each blow are shown in FIG. 4 as a continuous blow waveform. In FIG. 4, the solid line shows the impact waveforms 23, . . . , 23 in the hammer mechanism, and the broken line shows the output waveform 24 after integration. That is, the impact waveforms 23...23 are the output characteristics of the signal amplifying section 4 (FIG. 1), and the output waveform 24
shows the output characteristics at the waveform integrator 5 (FIG. 1).

This output waveform 24 (integrated output) shows a large change at the start of the impact (rise) of each impact waveform 23, and its slope gradually becomes gentler as time T passes. The degree of slope of the output waveform 24 can be changed by changing the capacitance of capacitor C and the resistance value of resistor R in FIG. The integrated value after the elapse of time is determined, and it becomes possible to judge the quality of the tightening ability of the impact wrench based on the integrated value.

Furthermore, due to the power storage effect of the capacitor C of the waveform integrator 5 (FIG. 2), waveforms below the integrated output of the output waveform 24, such as the impact waveform 23A in FIG.
The characteristic is that an abnormally high input such as B does not have a large effect on the output value of the output waveform 24. Therefore, due to this feature, it is possible to measure any irregular impact, and the irregularity appears as a variation in the integrated output of the output waveform 24, and by measuring the reduction of this variation, it is possible to tighten the impact wrench. It becomes possible to evaluate whether the performance is good or bad.

Next, returning to FIG. 1 and explaining the waveform integrator 5 and subsequent parts,
The output signal 25 from the waveform integrator 5 is input to the hold section 6. Note that this output signal 25 has the output waveform 2 in FIG.
It has the characteristics shown in 4.

The time-up signal 15 from the measurement time setting section 9 is input to the hold section 6, and after the measurement time set by the time-up signal 15, the hold section 6 maintains a constant value so that the analog output value at that measurement time does not fluctuate. It has a function of holding the signal and outputting it as an analog output signal 26. This analog output signal 26 is input to the digital display section 7,
The digital display section 7 is configured to display the measured value as a digital value based on the analog output signal 26.

Further, the analog output signal 26 is also input to the output value comparison section 12. The set value signal 27 from the lower limit setting section 11 is also input to the output value comparison section 12, and the output value comparison section I2 compares the analog output signal 26 and the set value signal 27, and calculates the measured time of the impact wrench. It has a function of determining whether or not the impact output after the elapse of time has increased to a preset value or more. The set value of the lower limit value setting section 11 is set by a digital switch.

A pass/fail determination signal 28 is output from the output value comparison section I2, and the pass/fail determination signal 28 is input to the GO1NG display section 13. This GO1NG display section 13 shows the time up 1
No. 3 15 is input, and the GO/NG display section 13 has a function of displaying the pass/fail of the impact output (integrated value) of the impact wrench when the measurement time has elapsed using a lamp based on the pass/fail determination signal 28. are doing. Therefore, the operator must check whether the wrench has the specified tightening torque or not.
This can be easily determined by simply looking at the 1NG display section 13. This GO1NG display section 13 is a pass/fail display section in the claims.

Next, a method for checking the l-lux of an impact wrench will be explained with reference to FIG. As described above, the transducer 1 converts the striking torque of each strike of the hammer mechanism of the impact wrench into an intermittent electric signal (pulse voltage signal 2).

The electrical signal from the transducer 1 is transferred to the signal amplifying section 4.
The signal is amplified so as to facilitate signal processing in the subsequent waveform amplifying section 5. As shown in FIG. 4, the waveform amplification section 5 integrates each intermittent impact waveform 23...23 (electrical signal) from the transducer 1 by the power storage effect with the capacitor C, and generates a continuous output waveform 24. obtain. The digital display section 7 passes through the hold 6 and displays the output of the output waveform 24 at the point in time when the measurement time has elapsed as a digital value. On the other hand, Go, NG display section 1
3 displays whether or not the wrench has a preset torque based on the pass/fail determination signal 2 from the output comparison section 12 in an easy-to-visible manner using a lamp display.

In the above embodiment, as explained above, the performance of an impact wrench whose impact is unstable with each impact and it is difficult to accurately judge its practical ability can be evaluated over time by sequentially integrating the torque of each impact. It is possible to measure cumulative ability as the average ability.

As the hammer mechanism of an impact wrench wears or deteriorates, the hammer mechanism's strikes become more irregular and the torque level for each strike becomes more disparate, resulting in extremely high levels of input torque or extreme Input torques with different torque levels are mixed, including input torques with small levels. Therefore, when measuring the tightening torque with such an impact wrench,
For example, it is necessary to accurately measure torque even when extremely large and small pulses are mixed, such as the impact waveforms 23A and 23B shown in FIG. 4, but as in the embodiment of the present invention,
The output waveform 24 (broken line) in FIG. 4 is the impact waveform 23A.
, 23B as a whole, and the torque of the impact wrench can be accurately measured as the time-averaged integrated capacity due to the power storage action of the capacitor C.

In the above, an example was shown in which an impact wrench was used, but it is also possible to use other torque wrenches such as a so-called pulse wrench that generates torque via a hydraulic device.

Also, take out the voltage with the capacitor C in Fig. 2, and
If it is connected to a device (not shown) that graphs the output waveform 24 in the figure, it can be expressed in a form similar to the rise characteristic of the tightening torque during screw tightening with an impact wrench. It is also possible to determine the degree of decline in the performance of the impact wrench by referring to the output of the conversion device.

(Effects of the Invention) As described above, in the torque check method of the present invention and the torque checker device that implements the method, the impact torque for each impact within a certain measurement time is calculated as an integral called storage. The integrated value obtained by this integration can be read and compared with a preset reference value to determine the degree of decrease in torque wrench performance and whether or not the wrench performance is acceptable. Therefore, it is possible to eliminate torque measurement errors caused by the irregularity of the torque wrench's motion state, which varies with each stroke in the past, and to calculate the time in line with the actual tightening work, rather than the peak torque for each stroke, which has large fluctuations. The tightening ability of 1/inch torque can be accurately evaluated as the average ability accumulated over time.

In addition, the pass/fail indicator displays whether or not the tightening work was performed as specified, making it possible to determine at a glance whether the wrench ability is passing or not, improving the reliability of the tightening test work. be able to.

In particular, when the waveform integrator is configured as shown in FIG. 2, the slope of the output waveform shown in FIG. 4 can be adjusted by changing the capacitance of the capacitor and the resistance value of the resistor. By setting the capacitance and resistance values to optimal values, it is possible to calculate the integrated value of intermittent torque during the measurement time, and the quality of the tightening ability of the torque wrench can be determined based on this integrated value.

Furthermore, since a diode and an operational amplifier are provided in the backflow prevention rectifier circuit, the loss in the diode can be corrected by the operational amplifier, and the accuracy of the output waveform from the waveform integrator is improved.

Furthermore, when a signal amplification section is provided, the voltage signal from the transducer can be amplified by the signal amplifier,
Signal processing at each subsequent stage can be facilitated.

[Brief explanation of the drawing]

1 to 4 show the torque checker device of the present invention. FIG. 1 is a block diagram of the torque checker device, FIG. 2 is a circuit diagram of the waveform integration section, and FIG. 3 is a waveform for each stroke. FIG. 4 is a graph showing waveform conversion in the integrating section. FIG. 4 is a graph showing continuous waveform conversion within the measurement time. DESCRIPTION OF SYMBOLS 1... Torque transducer, 4... Signal amplification part, 5... Waveform integration part, 7... Digital display part (display part), 12... Output value comparison part, 13... Go, N
G display section (pass/fail display section), 16... rectifier circuit for backflow prevention, 17... diode, 18... operational amplifier, R
...Resistor, C...Capacitor.

Claims (1)

[Claims] 1. The impact torque that occurs intermittently as the torque wrench tightens is converted into a voltage signal proportional to the torque value and detected, and this voltage signal is kept constant by the power storage action of a capacitor. The tightening ability of the torque wrench is determined by integrating each impact torque over time and comparing the integrated torque value based on the voltage level between the electrodes of the capacitor with a preset reference value. How to check the torque of a torque wrench. 2. A transducer is installed that converts the impact torque that occurs intermittently when the torque wrench is tightened into a voltage signal proportional to the torque value, and the voltage signal from the transducer is converted into a voltage signal at each time within a certain period of time by the power storage effect of a capacitor. A waveform integrator is provided that integrates the impact torque and converts it into a voltage level between the electrodes of the capacitor, and compares the integrated torque value based on the voltage level between the electrodes of the capacitor with a preset reference torque value to generate a pass/fail determination signal. 1. A torque checker device for a torque wrench, comprising: an output value comparison section that outputs a pass/fail determination signal; and a pass/fail display section that displays pass/fail of wrench ability based on the pass/fail determination signal. 3. The waveform integrator applies the voltage signal from the transducer to the resistor and capacitor via a backflow prevention rectifier circuit consisting of a backflow prevention diode and an operational amplifier that corrects loss in the diode. A torque checker device for a torque wrench according to claim 2, wherein the torque checker device is configured as follows. 4. The torque checker device for a torque wrench according to claim 2, further comprising a signal amplifier for amplifying the voltage signal from the transducer between the transducer and the waveform integrator.