SU1732146A1 - Device for testing piston rings for shape correctness - Google Patents

Abstract

The invention relates to a measurement technique and can be used to control the quality of piston rings (PC). The purpose of the invention is to improve the measurement accuracy by eliminating the error associated with fluctuations in beam size. The laser beam is divided into two, forming two channels - the measuring and reference. The light beam in the measuring channel illuminates the gap between the templates and the PC installed in it. The beam of light in the reference channel is modulated and passes through a fixture with a calibrated diaphragm. Both beams fall on the sensitive area of a single photodetector. The signal is then amplified and processed, thereby generating a feedback signal of the gain of the processing unit, depending on the size of the light beam. 1 il. her

Description

The invention relates to a measurement technique and can be used to control the quality of piston rings (PC).

There are various devices for controlling the correctness of a PC PC, containing a light source, a template with a PC installed in it, and a photodetector that registers the luminous flux that passes between the template and the PC.

They give a large measurement error due to fluctuations in the power of the radiation of the light source.

Closest to the present invention is a device in which the indicated disadvantage is eliminated by automatically adjusting the gain (AGC) of the photodetector using a signal from an additional optical channel. The device contains a single-mode laser, a divider of the light beam to the measuring and additional channels, an optical device for directing, additional light beam to the photodetector, a template with a PC placed in it, installed in the additional channel, a photodetector, an amplifier, high and low frequency filters at the output of the amplifier, an AGC system connected to the low pass filter, and a recorder connected to the high pass filter, and a recording device.

The disadvantage of such a device is a large inaccuracy, due to the presence of the heating component.

one

e &

related to the size of a pumka.

The aim of the invention is to improve the measurement accuracy by eliminating the error associated with beam size fluctuations.

The drawing shows a block diagram of the device.

The device contains a light source such as a single-mode laser 1, a beam splitter 2 that divides the flow into measuring and additional channels, a pattern 3 for installing a piston ring 4 installed in the measuring channel, a modulator 5, and a fixture 6 with a calibrated diaphragm channel, and the distance from the light source to the template and to the device with a calibrated diaphragm is equal to each other, the photodetector 7 amplifier 8 electric signals, filters 9 and 10 low and high frequencies etstvenno whose inputs are electrically connected to the output amplifier 8, the AGC system 11 connected to the output of the low pass filter, and a recording device 12 connected to the output of the filter 10, high frequency.

The device works as follows.

The light beam from laser 1 is divided by a beam splitter 2 into two beams, one of which is directed to an additional channel, including modulator 5 and device 6 with a calibrated diaphragm, and the other falls on pattern 3 with a PC 4 installed in it. the gap in the pattern 3, the luminous flux of the measuring channel is converted into an electrical signal by a photodetector 7 The same photodetector converts the light flux incident on it from an additional channel after passing through the modulator 5 and the fixture 6. O The electrical signals from the output of the photodetector 7 are amplified by the amplifier 8. The amplified electric signals of the measuring and auxiliary channels are separated by filters 9 and 10 of the lower and higher frequencies, respectively, into two components. The constant component of the high-pass filter 10 is fed to the recording device 12, and

low j which

variable through the frequency filter 9 enters the AGC 11 controls the gain of the amplifier 8.

The magnitude of the alternating electrical signal is determined from the equation

0

Vp i

,

where I is the photodetector conversion coefficient $ g is the reflection coefficient of the beam splitter j, the laser radiation power; 30ti - the value of the calibrated

aperture

b is the width of the light beam. Gain amplifier c1

P ARU

TO,

 TO

(about)

jc Rlscaz / s

The magnitude of the constant electrical signal, fixed by the recorder 12, is

U

fast

 5 V30

(1-g) (o)

dUl J6ft / d Ml

WITH

five

0

where is, 5th - the gap between the ring and

pattern.

Thus, the magnitude of the recorded electrical signal, ipost const d WQert, is proportional only to the size of the gap between the PC and the template and does not depend on the fluctuations of either the radiation power or the beam size. This provides improved measurement accuracy. Placing the fixture 6 at a distance from the radiation source 1 equal to the distance from it to the pattern 3 is necessary to achieve equal beam sizes on the fixture and the pattern. The fixture with the exemplary gap is aligned along the axis of the additional beam in order not to affect the measurement fluctuations of the axis of the beam pattern.

Claims (1)

SS Invention Formula A device for checking the correctness of the shape of a piston ring, containing successively installed a laser and a beam divider forming the measuring and reference channels, a template intended for installing a controlled ring in it and located in the measuring channel, a light emitting modulator installed in the reference channel, a photodetector optically connected to the outputs of both channels, and a processing unit, electrically associated with a photodetector, different In order to increase the control accuracy by eliminating errors associated with fluctuations in the size of the light beam, it is equipped with a calibrated slit diaphragm installed along the beam axis in the reference channel at a distance along the beam axis from the laser, equal to the distance from the laser to the template. T