SU992174A1 - Apparatus for measuring durability of grain-to-metal contact in grinding process - Google Patents

Description

one

The invention relates to machine tools, primarily to the tool industry, and can be used in experimental studies of abrasive machining.

A device for determining the length of single slices, consisting of a magnet for separating the chips from the slit and a microscope for determining their length 1, is known.

The disadvantages of this device are more labor intensive and low measurement accuracy.

A device for determining the length and number of single slices, consisting of a circle with a conductive grain, a sample to be cut, two current collectors, a direct current source and a recording device 2, is also known.

The disadvantages of the device include: the inability to measure the actual duration of the contact, taking into account its discontinuity due to the presence of roughness; the impossibility of measuring the actual duration of any predetermined contact; the inability to register the total contact duration for a certain number of revolutions; inability to register duration

contact with a single bump of roughness.

In addition, difficulties arise in automating the registration and processing of received information.

5 The purpose of the invention is to increase the number of registered parameters, improve measurement accuracy and reduce the complexity of their processing.

This goal is achieved by the fact that a speed sensor, a pulse transformer, an electronic key-inverter, a chronometer frequency meter, an AND circuit, a signal generator, two counters are inserted into the device containing an abrasive wheel with a conductive grain, current collectors, a power source, a registering device. pulses, electromagnetic relay.

FIG. 1 shows a diagram of the device; in fig. 2 - diagram of signals in the scheme.

The device consists of an abrasive wheel 1 with a conductor 20 grain 2 built into it, connected via a current collector 3 to a power source 4 to which the storage oscilloscope 5 is connected, the primary winding of the pulse transformer. A 6, the load resistance R, the sensor of the footers consisting of a disk with slot 7, installed coaxially with circle 1, and fixed illuminators with photodiode 8. The secondary winding of the pulse transformer 6 is connected via the electronic key-inverter 9 to the input "Resetting the frequency meter 10, and through the contacts ate BI (Bj when the switch is in the "ON position) or P ,, relay contacts Pj is connected to the input of" Start Frequency-chronometer. The frequency meter has an output “Code for outputting a signal to a digital printer or to a computer. The output of the circuit “synchronization” is connected (depending on the operation mode) either to the output of the electronic key-inverter 9, or to the load resistance E. Load resistance R is connected to the first input of the AI circuit, the second input of which is connected to the secondary winding of the pulse transformer through the driver 12 6. The output of the circuit And 11 is connected to the input of the counter 13, and through the contacts of the relay of its program part - to the input of the counter 14. The output of the counter 13 through the normally closed contacts of the counter 14 is connected to the electromechanical relay 15. Devices It works as follows. During the grinding process, the conductive grain 2 contacts the rough surface of the metal sample. As a result, the electrical circuit closes: sample — conductive grain 2 — current collector 3 — power supply 4 — primary winding of pulse transformer 6, and a series of pulses (Fig. 2, signal U) appear on the primary winding of transformer 6, each corresponding to a contact 2 grains with a single protrusion of the roughness of the sample. These pulses are captured by a storage oscilloscope 5 for visual control of the signal. The pulse transformer differentiates the signal Ui, while the secondary winding of transformer 6 shows a series of pulses Uz (Fig. 2), which are fed through the BIJ contact of the switch to the input "Start of the chronometer frequency meter 10, and through the electronic key-inverter 9 to the input "Reset frequency counter-chronometer 10. The frequency counter-chronometer, for example, model F5041 works as follows. Each of the pulses U2, arriving at the Start input, with its leading edge, starts the frequency meter and starts the time reference. The negative pulse formed by the trailing edge of the Hi signal does not affect the operation of the chronometer frequency counter. This signal is inverted by the electronic key-inverter 9, with the leading edge of each of the pulses U coinciding with the falling edge of the signal U ,. The signal Uj, received at the input "Resetting the frequency of the frequency meter, causes the end of the time countdown and the output of the duration of the pulse corresponding to the duration of the contact, the display and the output" Code connected to the digital printing device or computer. The values of the duration of the subsequent pulses are summed with the previous one. At the same time, the counter 13, for example, model F5007, performs counting of revolutions of the circle at which grain 2 was in contact with the sample. This happens as follows. The sensor 8 turns, consisting of a stationary photodiode with an illuminator and a disk with a slot 7 located between them and fixed on the axis of the circle 1, when turning on the rotation of the circle 1 begins to pass voltage pulses with a frequency equal to the frequency of rotation of the circle 11. At the output of the circuit, And the signal is absent until the conductive grain 2 contacts the metal. Upon contact of grain 2 with the metal of the sample, the signal U2 from the secondary winding of the pulse transformer 6 is fed to the signal conditioner 12, the parameters of which are chosen so that the pulse time at its output is equal to half the time of a circle turn. Thus, at the output of the circuit AND, a signal appears (one per revolution of the circle) only under the condition of simultaneous rotation of circle 1 and the presence of contact of grain 2 with the metal. This eliminates the false positives of the counter 13, which is connected to the output of the circuit 11 and registers the number of revolutions of the circle at which grain 2 was in contact with the metal. In case it is necessary to measure the duration of contact for j revolutions, starting with i-ro turn, contact B is open (1 switch B |. In this case, the signals from the secondary winding of the pulse transformer 6 are not initially input to the start of the chronometer frequency meter and the circuit operates as follows: Counter 13 registers the number of revolutions of the circle at which grain 2 was in contact with the metal. When the number of revolutions equal to j specified on the program panel of counter 13 is reached, its programmable relay contacts close Amma part and output voltage appears, which is fed through the normally closed contacts of the counter 14 to the winding of the electromagnetic relay 15. It triggers. After that, the pulses from the secondary winding of the pulse transformer 6 through the contacts of the relay 1, enter the "Start of the frequency meter 10 , which registers the duration of the contact of the grain with the metal.At the same time, the frequency meter-chronometer 10 works in the same way as with the closed contacts BIJ.

At the same time, through the contacts of the relay of the counter 13, the signal from the output of the circuit AND to the input of the counter 14. When the number of revolutions equal to i, accumulated on the software panel of the counter 14 is reached, the contacts of its relay part open, de-energizing the relay 15, which causes the contacts P to open. After that, the pulses from the secondary winding of the pulse transformer 6 are not received at the start of the frequency meter, the contact duration is stopped, its value is displayed on the frequency meter 10, and the code for the contact duration is output at the code for printing or further processing on the computer.

The frequency of receiving information from the output "The code is determined by the position of the switch Bj, which sets the frequency of the clock pulses at the output of the" Sync. If the switch Bjj is in the "O" position, then the sync pulses come from the rotation sensor with the frequency of rotation of the circle. The total contact duration on each turn of the circle is recorded. If switch B is in the “b” position, then the sync pulses come from the output of inverter 9, i.e. after each contact of the grain with separate protrusions of roughness, which allows tracing the dynamics of contact.

When using the proposed device, the accuracy and reliability of the results is increased, the time for data processing and their registration is reduced, the reliability of operation and the number of recorded parameters are improved.

Claims (2)

Invention Formula A device for measuring the duration of contact of the grain with the metal during grinding, containing an abrasive wheel with a current-conducting grain, a power source connected through a current collector to the specified grain and through a recording device with the workpiece, characterized in that parameters, improving measurement accuracy and reducing the complexity of their processing; a frequency meter with the Start and Reset and Output inputs are entered into it. A pulse transformer, the primary winding of which is connected to a recording device, an electronic inverter key, whose input is connected to the secondary winding transformer, and the output with the input "Reset the frequency meter, a switch designed to connect the secondary winding of the transformer with the input" Start the frequency meter, the sensor speed of the grinding wheel, made in the form of a disk with a slot fixed on the wheel and an illuminator with a photodiode connected in parallel with the load resistance to the power source, the AND circuit, the first input of which is connected to the load resistance, a signal conditioner whose input is connected to the secondary winding of the transformer, and the output to the second input of the circuit And, two software, pulse counters, one of which is connected to the output of the circuit AND directly, and the other through a serially connected switch and normally open contacts of the relay of the program part of the first 5 counter, electromagnetic relay connected via normally closed contacts of the second counter to the output of the first pulse counter, and with the help of normally open contacts of the indicated electromagnetic relay the secondary winding of the transformer is connected to the Start of frequency meter input, in addition, the device is equipped with the Synchronization output for setting periodically issuing information on the pulse duration from the output “The code is often a tomer, while the output“ Synchronization through the switch is connected to the load resistance or with the key-inverter output. Sources of information taken into account during the examination 1. E. Maslov. Theory of grinding materials. M., “Mechanical Engineering, 1974, p. 21. 2. USSR author's certificate No. 638456, cl. B 24 B 51/00, 1978. About 11 Well g e) ig.2