RU1803735C - Device for checking quality of male thread - Google Patents

Abstract

Usage: the invention relates to a measurement technique and can be used for automatic quality control of parts having an external threaded surface. The device comprises a laser 1, a collimator 2, a beam splitting unit 4, two illuminating optical fibers 5, at the output ends of which circular sections b and 7 are installed in an annular section, as well as four receiving fiber-optic collectors 8, 9, 10, 11, the input ends of which facing the thread at an angle of 60 ° to the axis of the illuminating fiber, and on

Description

Lack of HOJMWUP defektoz derekhto

FIG. 1

each of the weekends has photodetectors. The information processing system is constructed in such a way that it separates the signal from the receivers into constant and variable components and, after analyzing each, reveals

deviation from the nominal average diameter of the thread, its pitch, registers the presence of surface defects. In this case, the error of the base of the controlled part relative to the device is automatically excluded. 3 ill.

The present invention relates to the field of measurement technology and may find application in the automatic quality control of products having a threaded surface.

The purpose of this solution is to increase the information content in thread quality control by determining its parameters such as pitch n and average diameter dcp, as well as identifying defects of the entire threaded surface such as nicks, burrs, shavings between coils, and cutting of profile tips. Another objective of the present invention is neither to increase the reliability of the control by simultaneously illuminating the entire surface of the thread and to eliminate the influence of the error of the base of the controlled part relative to the device on the results of the monitoring,

In FIG. 1 shows a schematic diagram of a device; in FIG. 2 is a functional diagram of an apparatus for integrated quality control of threaded surfaces; in FIG. 3 - timing diagrams of the device signals.

The device shown in FIG. 1, contains a radiation source, for example, a laser 1, a collimator 2, a node for dividing the beam into 2 parts according to intensity 3, 4, located on one optical axis. As a beam splitting unit, in particular, a set of two mirrors, translucent 4 and reflective 3, can be used. On each of the optical axes of the two beams into which the laser beam is divided, illuminating fiber optic fibers 5 are installed, the input ends of which have a cross section in the form of a circle, the diameter of which is equal to the diameter of the laser beam, and the output section is in the form of a half ring and installed along the helix of the thread of the controlled product so that the light sweat formed in the form of a focused half ring It appears parallel to the line of the thread crests and troughs of the illuminated within each half-ring, and an inflection region is outside the illuminated area. Cylindrical lenses 6, 7, also made in the form of half rings, are installed close to each of the output ends of the fiber illuminating optical fibers, the focus of each lens being at the level of the nominal average diameter of the thread. Each of the illuminating fibers is surrounded by

two receiving fiber optic collectors 8-11. The input ends of the collectors are made in the form of half rings and are arranged in pairs at an angle of 60 ° to each of the illuminating optical fibers (6-8.9; 7-10, 11).

The angle of 60 ° is selected from the conditions for obtaining at the radiation receiver a diffuse component reflected from each face of the light flux and excluding the ingress of a mirror component at the input end

upon re-reflection from the adjacent face of the thread profile. The output ends of each are divided into at least two parts and have a circle in cross section. In FIG. 1, each of the fiber optic collectors is divided into 3 parts. An increase in the number of parts increases the sensitivity of the device and its resolution. The output ends of the fiber optic collectors 8, 9, 10, 11 are connected closely to the radiation detectors 12-23. A controlled threaded product is connected to a node 42, which provides its translational movement relative to the incident ring beams. At the output of each receiver

Radiation amplifiers 24 are installed through a low-pass filter 25 connected to the input of the sampling-storage device (CVX) 26 and to the first input of the adder 28. The output of the UVX 26 through the normalizing

an amplifier 27 is connected to the second input of the adder 28. The output of the adder 28 is connected to the input of the comparator 29 and through the high-pass filter 34 to the first input of the comparator 35, the gate input

which is connected to the first output of the block, forming the gating voltage (BPSN) 41, and the output with one of the inputs of the element И И И 36. The output of the comparator 29 is connected to the input S of the RS-trigger 30. The output of this trigger is connected to the input D of the trigger 31. Outputs C and R, respectively, of the triggers 31 and 30 are combined and connected to the second output of the BPSN of the gate voltage generating unit 41 and to the control input of the UVX 26, the third output of the BPSN is connected to the gate of the comparator 29 and through the delay element 33 to the recording enable input of the trigger 30. Trigger Out EPA 31 associated with one of the inputs of OR element 32.

The output of the normalizing amplifier 27 is connected to the first input of the adder 37. The output of the adder is connected to the first input of the comparator 38. The second input of this comparator is connected to the first output of the control device 40, and the output of the comparator is connected to one of the inputs of the OR element 39. The second output of the control device is connected with the second input of the comparator 35, and the third output with the input of the BFSN 41. The device operates as follows.

The luminous flux of the radiation source 1 is expanded by the collimator 2 to a diameter equal to the diameter of the input ends of the fiber optic optical fibers 5; intensities into two equal parts, one of which is fed to the input end of the right fiber, and the other to the input end of the left fiber. Due to the fact that the output ends of the optical fibers are made in the form of half rings, and they themselves have irregular stacking, the luminous flux is formed in the form of half rings. Cylindrical lenses b and 7 mounted on the output ends focus the light flux in the form of half rings. In this case, the focal lengths of the lenses are selected so that if the average radius of the thread corresponds to the nominal value and the axis of rotation of the part coincides with the axis of the semicircular illuminating optical fibers, the middle of the focus of the focused stream is at the level of the average radius of the thread. When moving a controlled threaded translational surface relative to the laser beam, the latter scans the entire threaded surface, moving along each face of the profile. Due to the fact that the illuminating ring sections are displaced relative to each other, the area of the threaded surface where the profile crosses does not enter the zone of their action, which can otherwise be registered as a defect. The luminous flux reflected from the surface of each face in the zone of the diffuse component is perceived by the corresponding fiber-optic receiving optical fiber 8:11 (Fig. 1a). If there is a defect on the edge of the threaded profile, the indicatrix deviates

scattering, as shown in FIG. 16. The corresponding section of each of the 4 receiving optical fibers receives an increase in the reflected light flux and at the output associated with it

0 of the radiation receiver, the waveform corresponds to that shown in FIG. 3 p. 1. The signal from the output of the photodetector, for example, 13 is amplified by an amplifier 24 and passes through a low-pass filter 25, which implements

5 filtering the noise component of the signal. The waveform at the filter output is shown in Fig. 3 p. 2. This signal has a constant component, the value of which carries information about the deviation of the average thread diameter from the nominal one. For

revealing this constant component

a retrieval-storage device is used

- UVX 26. The signal at the output of the UVX comes from

output filter 26. The GCM is controlled by 5 gating pulses generated in the gating voltage generating unit (BPSN) 41. The position of these pulses relative to the original signal is shown in FIG. 3, item 5. On the

A constant voltage corresponding to the signal level from the darkened portions of the thread is formed at the output of the I – V characteristic. The voltage from the output of the UVC through the normalizing amplifier 27 is supplied to the first input

5 of the adder 37. The second input of this adder receives a signal from the output of the normalizing amplifier channel, the photodetector of which is located diametrically opposite to the photodetector 13, for example

0 22. As a result of subtracting these two signals, which is necessary to eliminate the error due to the error in the base of the part, the voltage proportional to the deviation of the diameter is generated at the output of the adder 36

5 parts from the nominal. This voltage is supplied to the first input of the comparator 38 and compared with the reference voltage supplied to the second input of the comparator from the control device 40. In the case when

0, the voltage at the first input of the comparator 38 exceeds the threshold level, a signal is generated at the output of this comparator through an IL AND 39 element to the diameter deviation registration circuit.

5 The thread pitch of the controlled part is determined by the variable component of the signal from the output of the filter 25. The allocation of the variable component is carried out on the adder 28, to one input of which the signal from the output of the filter 25 is received, and

the other from the output of the normalizing amplifier 27. The shape of the resulting signal at the output of the adder 28 corresponding in time to the illuminated portions of the thread is shown in FIG. 3 p. 6. The voltage output from the adder 28 is compared by a comparator 29 with a zero level at the time of operation of the strobator generated by the BPSN unit (Fig. 3, item 4). As a result, if the thread pitch corresponds to the nominal one, positive pulses are generated at the output of the comparator (Fig. 3, item 7), which, with their leading edge, set the RS flip-flop 30 to the state of a logical unit.

This information is copied along the leading edge of the strobe (Fig. 3, item 5) to the D-flip-flop 31, and on the trailing edge of the strobe the RS-flip-flop is reset. If the thread pitch is exceeded, the nominal pulses are absent at the output of the comparator and at the output the inverse of the D-flip-flop is the level of a logical unit, which is summed up according to the circuit. OR 32 with signals from other channels and enters the registration circuit deviation of the thread pitch from the nominal. In case of deviation of the thread pitch to a smaller side, pulses occur at the output of the comparator (Fig. 3, item 7). However, since 6 in this case, their leading edge coincides with the leading edge of the strobe (Fig. 3, item 4) and the write enable pulse arrives at trigger 30 with a slight delay with respect to this strobe defined by element 33, then logical 1 trigger 30 in this case does not occur, and at the output of this trigger, and therefore trigger 31, there is also information about the deviation of the step from the nominal

The presence of defects on the surface of the controlled thread is determined by the presence in this case of high-frequency components in the signal spectrum. These high-frequency components are extracted from the output signal of the adder 28 by the high-pass filter 34. As a result, the signal shown in FIG. 3. p.10. This signal is compared with the reference voltage generated by the control device 40. In the case of a signal from a defect, a positive pulse is generated at the output of the comparator, which is added to the signals from other channels of the device at the output of the OR circuit 36 and fed to the defect registration circuit. The strobe voltage generating unit 41 provides the formation of these voltages with parameters that vary depending on the signals of the device

control 40. The control device 40 is a RAM or PCB with output DACs and, depending on the size of the controlled parts

certain values of the reference voltages and control codes of the unit 41.

SUMMARY OF THE INVENTION An apparatus for controlling the quality of an external thread, comprising a radiation source, optically coupled a focusing unit and a radiation receiver, a signal processing circuit, characterized in that, in order to increase the information content and reliability of the control, it is equipped with sequentially located between the radiation source and a focusing unit, a collimator and a unit for separating the radiation flux in intensity into the first and second beams, the first and second fiber optic

illuminating optical fibers placed respectively along the first and second radiation beams, the input ends of each of the optical fibers are made in the form of a circle, the output ends are in the form of half rings designed for installation along a helical line of a controlled thread so that the beams of illuminating radiation are parallel to the lines of the crests and troughs of the thread , the focusing unit is made in the form of first and second cylindrical lenses in the form of half rings mounted at the output of the corresponding first and second fiber-optic illuminating light s two pairs of manifolds, pairwise symmetrically

located respectively relative to the axes of the first and second illuminating optical fibers at an angle of 60 ° to the axes of each of them, the input ends of each of the collectors are made in the form of half rings, the output

the ends are divided into n parts, where n 2, the cross section of each of which is a circle, the radiation detector is made in the form of n photodetectors, each of which is connected to the output end of the collector;

the signal processing circuit is made in the form of n channels, each of which consists of a series-connected amplifier, a low-pass filter, a sampling-storage device, a normalizing amplifier of the first adder, the first comparator, RS-flip-flop and D-flip-flop, a strobe voltage generating block, in series connected high-pass filter and delay element, second comparator, serially connected second adder, third comparator and .element OR, control unit, block forming gate On the other hand, the output of the sampling-storage device is connected to the second input of the first adder, the output of the first adder is connected through a high-pass filter and to the first input of the second comparator, the gating input of the second comparator is connected to the first output of the gate voltage generating unit, and the output is with the first input of the first OR element, the gate voltage generating unit, the second output of which is connected to the control input of the sampling-storage device, with the reset input of the RS-trigger and the D-trigger clock input, and the third output forming block gating voltage is coupled to the gating input of the first comparator and via a delay element - to the input of flip-flop RS-resolution recording, S-input RSLEySchU

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the trigger is connected to the output of the first comparator, and the output of the RS-trigger is connected to the D-input of the D-trigger, the output of the D-trigger is connected to the first input of the second OR element, and the output of the normalizing amplifier is connected to the first input of the second adder, the output of the second adder is connected with the first input of the third comparator, and the output of the third comparator is connected to the first input, while the second input of the third comparator is connected to the first output of the control unit, the second output of the control unit is connected to the second input of the second comparator, and the third output of the unit systematic way connected to the input unit generating a gate voltage.

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