RU2429457C1 - Method of measuring threaded joint tightening force and torque wrench to this end - Google Patents

Abstract

FIELD: physics. ^ SUBSTANCE: proposed method comprises applying torque to tightened thread joint, driving said threaded joint to turn its through preset angle not exceeding 2Ç4 of torque measurement, additional turn of said joint through the same angle with changing torque, measurement of torque, and screwing off threaded joint through preset angle equal to that of turn in tightening with measurement of screwing-off torque. Then joint is turned is additionally turned through the same angle with measurement with screwing-off torque and determining axial tightening force as , where Ft is axial tightening force, P is thread pitch, M1tight is tightening torque in initial turn through preset angle, M2tight is tightening torque in additional turn through preset angle, M1screw-off is torque in screwing-off through preset angle, M2screw-off is torque in additional screwing-off through preset angle. Torque wrench comprises torque pickup connected to amplifier input. Amplifier output is connected to ADC input. It comprises also first and second memory registers with their data inputs connected to ADC outputs and their outputs connected to data inputs of computer with its data outputs connected to digital indicator inputs, angle pickup with its output connected to count input of pulse counter with its outputs connected to decoder inputs, first OR element with its output connected first indicator input and its first and second inputs connected to zero and first inputs of decoder with its first output connected to input "Record" of first memory register. Decoder second output is connected to input "Record" of second memory register. Set inputs of first and second memory registers and those of pulse counter are connected via control pushbutton to bus "Logical unity Voltage". It comprises also second indicator of third and fourth memory registers, second and third OR elements and third and fourth indicators. Data inputs of third and fourth memory registers are connected to ADV outputs while data outputs are connected to computer data inputs. Input "Record" of third memory register is connected with decoder third output. Input "Record" of fourth memory register is connected with decoder fourth output. Set inputs of third and fourth memory registers are connected with set inputs of first and second memory registers. Decoder fourth output is connected to computer "computation" input and to input of second indicator. Decoder second and third outputs are connected to inputs of second OR element. Outputs of first and second OR element are connected to inputs of third OR element with its output connected to third indicator input. Second OR element output is connected to fourth indicator input. ^ EFFECT: higher accuracy of tightening torque control. ^ 2 cl, 3 dwg

Description

The invention relates to measuring technique and can be used to control the axial tightening force of threaded joints.

A known method of measuring the axial tightening force of threaded connections, which consists in applying torque to a tightened threaded connection, translating the threaded connection from a rest state to a motion state, turning a predetermined angle not exceeding 2-4 ° of a torque measurement when the rotation angle reaches a predetermined value, additional rotation of the threaded connection at the same angle with the measurement of torque when the angle of rotation reaches the set value (see patent RU No. 2367917).

However, the use of this method does not allow to accurately determine the axial tightening force, so the tightening torque is measured, which is functionally related to the axial tightening force.

However, a significant spread of the friction coefficients in the thread and along the end face of the nut leads to a significant error in the measurement of the axial torque by the magnitude of the torque.

The technical result of the invention is to increase the accuracy of control of the axial tightening force.

The technical result achieved is achieved by the fact that according to the method of measuring the axial tightening force, which consists in applying torque to the tightened threaded connection, the threaded connection is transferred from the rest state to the motion state, rotation by a predetermined angle not exceeding 2-4 ° of the torque measurement when reaching the angle of rotation of the set value, an additional rotation of the threaded connection at the same angle with the measurement of torque when the angle of rotation of the set value is achieved, tvinchivanie threaded connection at a predetermined angle equal to the angle of rotation when tightened monitoring the torque unscrewing when the rotation angle of predetermined value, then produce a further rotation of the same angle with the torque loosening the measurement when the angle of rotation of predetermined value, and the axial tightening force is defined as

F _Z - axial tightening force;

P is the thread pitch;

M _1at - tightening torque during initial rotation by a given angle;

M _2zat - tightening torque with an additional rotation by a given angle;

M _1otv - torque when unscrewing at a given angle;

M _2otv - torque with additional unscrewing at a given angle.

Known torque wrench containing a torque sensor connected to the input of the amplifier, the output connected to the input of the analog-to-digital Converter, the first and second memory registers, the information inputs connected to the outputs of the analog-to-digital Converter, and the outputs to the information inputs of the calculation unit, the information outputs connected to the inputs of the digital indicator, the angle sensor, the output connected to the counting input of the pulse counter, the outputs connected to the inputs of the decoder, the first element "OR", the output connected to the input of the first indicator, the first and second input connected to the zero and first input of the decoder, the first output of the decoder is connected to the “Record” input of the first memory register, the second output of the decoder is connected to the “Record” input of the second memory register, installation inputs of the first and second the memory register and the pulse counter through the control button connected to the bus "voltage logical unit" and a second indicator (see patent RU No. 2367917).

The disadvantage of this key is the insufficiently high accuracy of measuring the axial tightening force.

The technical result of the invention is to increase the accuracy of measuring the axial tightening force.

The technical result is achieved by the fact that a torque wrench containing a torque sensor connected to the input of the amplifier, an output connected to the input of the analog-to-digital converter, first and second memory registers, information inputs connected to the outputs of the analog-to-digital converter, and outputs to information inputs of the unit calculations, information outputs connected to the inputs of a digital indicator, an angle sensor, an output connected to the counting input of the pulse counter, outputs connected go with the inputs of the decoder, the first element "OR", the output connected to the input of the first indicator, the first and second input connected to the zero and first input of the decoder, the first output of the decoder is connected to the input "Record" of the first memory register, the second output of the decoder is connected to the input " Record ”of the second memory register, the installation inputs of the first and second memory registers and the pulse counter through the control button are connected to the bus“ Logic unit voltage ”and the second indicator is equipped with a third and fourth memory register and, with the second and third “OR” elements and the third and fourth indicators, the information inputs of the third and fourth memory registers are connected to the outputs of the analog-to-digital converter, the information outputs are connected to the information inputs of the computing unit, the “Record” input of the third memory register is connected to the third output of the decoder, the “Record” input of the fourth memory register is connected to the fourth output of the decoder, the installation inputs of the third and fourth memory registers are connected to the installation inputs of the first and second registers memory, the fourth output of the decoder is connected to the input "Calculation" of the calculation unit and the input of the second indication element, the second and third outputs of the decoder are connected to the inputs of the second element "OR", the outputs of the first and second elements "OR" are connected to the inputs of the third element "OR", the output connected to the input of the third indicator, and the output of the second OR element is connected to the input of the fourth indicator.

Figure 1 shows a graph of the dependence of the tightening torque, unscrewing torque and axial tightening force on the angle of rotation of the nut when tightening the threaded connections.

Figure 2 - General view of the torque wrench.

Figure 3 shows a block diagram of a torque wrench.

The torque wrench contains a torque sensor 1 connected to the input of the amplifier 2, the output connected to the input of the analog-to-digital converter 3, the first and second memory registers 4 and 5, the information inputs connected to the outputs of the analog-digital converter 3, and the outputs to the information inputs of block 6 calculations, information outputs connected to the inputs of the digital indicator 7, the angle sensor 8, the output connected to the counting input of the counter 9 pulses, the outputs connected to the inputs of the decoder 10, the first element 11 "AND LI ”, the output connected to the input of the first indicator 12, the first and second input connected to the zero and first input of the decoder 10, the first output of the decoder 10 is connected to the“ Record ”input of the first memory register 4, the second output of the decoder 10 is connected to the“ Record ”input of the second memory register 5, the installation inputs of the first and second memory registers 4 and 5 and the counter 9 pulses through the control button 13 are connected to the bus 14 "logical unit voltage", the third and fourth 15 and 16 memory registers, the second and third 17 and 18 elements "OR "And the second, tre the first and third indicators 19, 20 and 21, the information inputs of the third and fourth 15 and 16 memory registers are connected to the outputs of the analog-to-digital converter 3, the information outputs are connected to the information inputs of the computing unit 6, the “Record” input of the third memory register 15 is connected to the third the output of the decoder 10, the input "Record" of the fourth memory register 16 is connected to the fourth output of the decoder 10, the installation inputs of the third and fourth memory registers 15 and 16 are connected to the installation inputs of the first and second memory registers 4 and 5, the fourth the output of the decoder 10 is connected to the input "Calculation" of the calculation unit 6 and the input of the second indication element 19, the second and third outputs of the decoder are connected to the inputs of the second element OR 17, the outputs of the first and second elements 11 and 17 OR are connected to the inputs of the third element 18 "OR", the output connected to the input of the third indicator 20, and the output of the second element "OR" is connected to the input of the fourth indicator 21.

A method of measuring the axial tightening force of a threaded connection is as follows.

The key head of a torque wrench (not specified) is put on the tightened threaded connection and the threaded connection is rotated. When the rotation angle reaches the set value 2 ÷ 4 °, a torque measurement is performed. Then make an additional rotation at the same angle, when the angle reaches the set value, make a second measurement of torque, then unscrew the threaded connection to a predetermined angle equal to the angle of rotation when tightening with measurement of the unscrewing torque when the angle of rotation reaches the specified value, then make an additional rotation at the same angle with the measurement of the unscrewing torque when the rotation angle reaches the set value, and the axial tightening force is determined as

F _Z - axial tightening force;

P is the thread pitch;

M _1at - tightening torque during initial rotation by a given angle;

M _2zat - tightening torque with an additional rotation by a given angle;

M _1otv - torque when unscrewing at a given angle;

M _2otv - torque with additional unscrewing at a given angle.

The torque wrench works as follows.

Previously, in the key calculation unit 6, the values of the thread pitch value of the controlled threaded connection (not specified) are entered.

Then, with a key head (not specified), the key is mounted on a threaded connection (not specified) and the control button 13 is pressed. In this case, the contents of memory registers 4, 5, 15 and 16 are reset and counter 9 is set to its initial state.

This leads to the appearance of a voltage of a logical unit at the zero output of the decoder 10.

The voltage of the logical unit appears at the outputs of the elements 11 and 18 "OR", which is fed to the inputs of the elements 12 and 20 of the display.

The “Tightening” indication element 12 and the “Measurement” indication element 20 light up, thereby indicating the start of measurement.

Then, a torque is applied to the threaded connection and the threaded connection is transferred from the rest state to the motion state and rotate it.

In this case, a voltage appears at the output of the torque sensor 1, the value of which is proportional to the value of the applied torque. This voltage is supplied through an amplifier 2 to the input of an analog-to-digital converter 3, which converts the voltage proportional to the moment into a digital code.

The digital code from the outputs of the analog-to-digital Converter 3 is fed to the inputs of the registers 4, 5, 15 and 16 of the memory.

When, when turning the threaded connection, the rotation angle reaches the set value within 2 ÷ 4 °, an impulse will appear at the output of the angle sensor 8, which is fed to the counting input of the 9 pulse counter.

At the same time, at the zero output of the decoder 10, the voltage of the logical unit disappears, and it appears at the first output of the decoder 10. The leading edge of this pulse is written to the memory of the first register 4 of the code at its inputs corresponding to the amount of torque at the initial angle of rotation.

With a further rotation of the threaded connection, an impulse will reappear at the output of the angle sensor 8, when the threaded connection is rotated by the same angle as during the initial rotation. In this case, the counter 9 pulses will be installed in the following state, the logical unit voltage will appear at the second output of the decoder 10, which is used to write to the memory of the second memory register 5 when it corresponds to the torque when the threaded connection is rotated by an additional angle.

Since the voltage of the logical unit disappears at the first output of the decoder 10, the voltage of the logical unit also disappears at the output of the OR element 11, the Puff indication element 12 goes out and the Unscrew indication element 21 lights up, since the voltage of the logical unit appears on the second decoder output 10.

Unscrew the threaded connection at an angle equal to the angle of rotation when tightening.

When, when unscrewing, the rotation angle reaches the set value within 2 ÷ 4 °, an impulse will appear at the output of the angle sensor 8, by which the counter 9 is set to the next state.

At the same time, the voltage of the logical unit appears on the third output of the decoder 10, by which the code corresponding to the unscrewing torque when unscrewing the threaded connection to a given angle is recorded in the memory of the third register 15.

Then produce unscrewing the threaded connection to an additional angle.

When the rotation angle reaches the set value, the pulse appears again at the output of the angle sensor 8, which switches the pulse counter 9 to the next state, the logic unit voltage disappears at the third output of the decoder 10, and the logic unit voltage appears at the fourth output of the decoder 10. The voltage from the output of the decoder 10 , from the outputs of the analog-to-digital Converter 3 is written into the memory of the fourth register 16 of the memory code corresponding to the torque when unscrewing the threaded connection to the additional itelny angle.

The digital code from the outputs of the registers 4, 5, 15 and 16 of the memory is fed to the inputs of the block 6 calculations.

When the logical unit voltage appears on the fourth output of the decoder 10, unit 6 calculates the axial tightening force by the formula

F _Z - axial tightening force;

P is the thread pitch;

M _1at - tightening torque during initial rotation by a given angle;

M _2zat - tightening torque with an additional rotation by a given angle;

M _1otv - torque when unscrewing at a given angle;

M _2otv - torque with additional unscrewing at a given angle.

The code from the outputs of block 6 of the calculation is supplied to the inputs of a digital indicator 7, which is used to indicate the calculated value of the axial torque.

Since the logical unit voltage disappears at the third output of the decoder 10, the “Measurement” and 21 “Unscrew” indicators 20 go out, and the “Result” indicator 19 lights up, since the voltage of the logical unit appears at the fourth output of the decoder 10, which indicates that measurement is complete.

The measurement of the axial tightening force is completed and the wrench is removed from the tested threaded connection.

Introduction to a torque wrench containing a torque sensor connected to an amplifier input, an output connected to an analog-to-digital converter input, first and second memory registers, information inputs connected to the outputs of an analog-to-digital converter, and outputs to information inputs of a calculation unit, information outputs connected to the inputs of the digital indicator, the angle sensor, the output connected to the counting input of the pulse counter, the outputs connected to the inputs of the decoder, the first element "OR ", The output connected to the input of the first indicator, the first and second input connected to the zero and first input of the decoder, the first output of the decoder is connected to the input" Record "of the first memory register, the second output of the decoder is connected to the input" Record "of the second memory register, the installation inputs of the first and the second memory register and the pulse counter through the control button connected to the bus "voltage logical unit" and the second indicator, the third and fourth memory registers, the second and third elements "OR" and the third and h of the fourth indicators, the information inputs of the third and fourth memory registers are connected to the outputs of the analog-to-digital converter, the information outputs are connected to the information inputs of the calculation unit, the “Record” input of the third memory register is connected to the third output of the decoder, the “Record” input of the fourth memory register is connected to the fourth the output of the decoder, the installation inputs of the third and fourth memory registers are connected to the installation inputs of the first and second memory registers, the fourth output of the decoder is connected to by the "Calculation" of the calculation unit and the input of the second indication element, the second and third outputs of the decoder are connected to the inputs of the second element "OR", the outputs of the first and second elements "OR" are connected to the inputs of the third element "OR", the output connected to the input of the third indicator, and the output of the second "OR" element is connected to the input of the fourth indicator, which allowed to increase the accuracy of measuring the axial torque.

Claims (2)

1. A method of measuring the axial tightening force of a threaded joint, which consists in applying torque to a tightened threaded joint, turning the threaded joint from a rest state to a motion state, turning a predetermined angle not exceeding 2-4 ° of torque measurement when the turning angle reaches a predetermined value , an additional rotation of the threaded connection at the same angle with the measurement of torque when the angle of rotation reaches a predetermined value, characterized in that they unscrew the threaded about the connection at a given angle equal to the angle of rotation when tightening with measurement of the unscrewing torque when the rotation angle reaches the set value, then make an additional rotation at the same angle with measuring the unscrewing torque when the rotation angle reaches the set value, and the axial torque is determined as

where F _Z - axial torque
P - thread pitch
M _{1 Zat} - tightening torque during initial rotation by a given angle,
M _2zat - tightening torque with an additional rotation at a given angle,
M _1otv - torque when unscrewing at a given angle,
M _2otv - torque with additional unscrewing at a given angle. 2. A torque wrench containing a torque sensor connected to an amplifier input connected to an analog-to-digital converter output, first and second memory registers, information inputs connected to the outputs of the analog-to-digital converter, and outputs to information inputs of the calculation unit, information outputs connected to the inputs of a digital indicator, an angle sensor, the output connected to the counting input of the pulse counter, the outputs connected to the inputs of the decoder, the first element "OR", the output m connected to the input of the first indicator, the first and second inputs connected to the zero and first inputs of the decoder, the first output of the decoder is connected to the “Record” input of the first memory register, the second output of the decoder is connected to the “Record” input of the second memory register, installation inputs of the first and second the memory registers and the pulse counter through the control button are connected to the bus "logical unit voltage", and a second indicator, characterized in that it is equipped with a third and fourth memory registers, the second and third elements “OR” and the third and fourth indicators, the information inputs of the third and fourth memory registers are connected to the outputs of the analog-to-digital converter, the information outputs are connected to the information inputs of the computing unit, the “Record” input of the third memory register is connected to the third output of the decoder, the “Record” input »The fourth memory register is connected to the fourth output of the decoder, the installation inputs of the third and fourth memory registers are connected to the installation inputs of the first and second memory registers, the fourth output is the fractor is connected to the input "Calculation" of the calculation unit and the input of the second indication element, the second and third outputs of the decoder are connected to the inputs of the second element "OR", the outputs of the first and second elements "OR" are connected to the inputs of the third element "OR", the output connected to the input the third indicator, and the output of the second OR element is connected to the input of the fourth indicator.

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