SU1642269A1 - Device for measuring temperature when grinding - Google Patents

Abstract

The invention relates to thermometry and makes it possible to increase efficiency by expanding the technological possibilities of measuring temperature when grinding gears. The electrodes of the thermocouples are plate-shaped and placed in the grinding wheel in the I planes, each plane being at an angle a with the axis of rotation of the grinding wheel, determined from the ratio given in the description. The electrodes of the thermocouple are closed through the surface of the workpiece and the output signal from them is proportional to the temperature in the working area. The device provides temperature measurement during the entire processing time on the involute gear profile, eliminates random failures in the measurement, ensuring reliable closure of the thermocouple electrodes in the cutting zone. The use of a statistical data processing algorithm with data sorting according to processing zones makes it possible in the end to ensure the defect-free processing of the tooth profile, automating the flow control during grinding gears. 3 il. sl C

Description

The invention is intended to measure the temperature in the cutting zone when grinding involute gears, and can be used to determine cutting conditions and optimize grinding processes.

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The aim of the invention is to increase efficiency by making it possible to measure the surface temperature of the cut gears.

FIG. 1 schematically shows an abrasive grinding wheel in which plate electrodes of thermocouples are placed in pairs parallel; in fig. 2 shows the orientation of the thermocouple electrodes relative to the axis of rotation of the grinding wheel; in fig. 3 cyclogram EMF i thermocouple for one revolution of the grinding wheel.

A device for measuring the surface temperature during grinding contains an abrasive grinding wheel 1 and placed in it plate electrodes 2 thermocouples, which are connected to an electronic data processing unit (not shown) using wires 3 and a current collector 4 through a switch 5. Thermocouple electrodes 2 are placed in a grinding wheel 1 in the slotted grooves, the bay and secured the slot with electrodes high-temperature putty, resins. Preliminarily, electrodes 2 are coated with an electrically insulating material (ceramic), ensuring the minimum distance between the plate Os.

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these electrodes 2 when they are placed. The thickness of the electrodes is 0.05-0.2 mm, which allows reducing the time constant of the thermocouple and ensuring the required accuracy of temperature measurement, i.e. minimize the error due to temperature gradients along the working end 6 of the electrodes 2 when the working end 6 of the electrodes 2 does not simultaneously contact the cutting zone 7 when grinding the workpiece 8. With the next editing of the circle, cutting the electrodes 2 along the working end 6 leads to a decrease in this point of the radius of the grinding wheel 1, which does not affect the subsequent measurement process. Thermocouple electrodes closed in pro; The process of grinding the surface to be machined is placed in the grinding wheel in i planes, each plane located at angles a with the axis of rotation of the grinding wheel defined by the expression

a) R TImi

cos arctg

sai (arctg

Jtrr

2 R

),

where ft is the maximum allowable angular frequency of rotation of the grinding wheel {a characteristic of the machine);

R is the working radius of the grinding wheel;

Ti is the time constant i of the thermocouple;

rnj - gear tooth modules, which cutting is possible on this grinding wheel.

This expression for a follows from the following: R T is the distance that the working end of the electrode plates runs for time T, and the time interval T provides cooling of the electrode end, which is necessary for accurate temperature measurement, and t is the distance between the teeth of the hearts ka, cut on a grinding wheel.

Thus, the angle a provides the required time interval between measurements, and also determines the duration of the signal for each measurement, allowing you to select an empirically optimal scheme for picking up and processing information; cosarctg m / 2R is the correction for the angle a which is determined by the inclination of the thread of the screw cut on the grinding wheel to the axis of rotation of the grinding wheel.

The size of the thermocouple electrodes along the radius of the grinding wheel is equal to the thickness of the working (wear) zone of the latter.

The device works as follows.

Before starting work, the switch 5 closes the wires 3 from the electrodes 2 of the thermocouple corresponding to the module of the tooth of the cut gear. Put into gear

profiles of an abrasive worm grinding wheel 1 and a grinding part 8. When the grinding surface closes in the cutting zone 7 of the electrodes 2 of the thermocouple, the signal of the thermo EMF through the switch 5,

0 current collector 4 is fed to the processing unit of the electronic unit. At existing speeds of rotation of the grinding wheel sh 1500-2000 rpm and grinding gear P2 10-60 rpm occurs up to 20-200

5 measurements / s on each gear tooth that is engaged. The electronic block using the time interval Ti,. distinguishes the signals coming from n different gear teeth, groups them into

0 arrays by the number p of the teeth that are in engagement, and calculates, builds the temperature field along the sections of the ground evolvent profile of the tooth, using the dependence of the temperature in the cutting zone on gra5AT

dienta -gj dt

R

T3

Shopping center

DT

at cf; /

Ј dt dt

to

where K is the number of measurements in the controlled area on a given gear tooth for K revolutions of the grinding wheel, determines the maximum temperature in the cutting zones on the n teeth and controls the cutting conditions,

ensuring flawless processing of the ground surface.

Measurement of surface temperature during grinding using the proposed device expands technological capabilities, provides temperature measurement during the entire processing time on an involute gear profile, eliminates random measurement failures, ensuring reliable electrode closure

thermocouples in the cutting zone, and, using a static data processing algorithm with data sorting by zone; machining, it allows to ensure defect-free machining of the part and improve processing accuracy by automating the flow control when grinding gears.

Claims (2)

Claim 1, A device for measuring surface temperature during grinding, containing an abrasive grinding wheel with thermocouple electrodes placed in it connected to an electronic recording unit, characterized in that, in order to increase efficiency by making it possible to measure the surface temperature of cut gears, the thermocouple electrodes are made plate and placed in the grinding wheel parallel to each other at an angle a to the axis of rotation, determined from the ratio , a) R T t. a (arcctg jrm cos arctg), where R is the working radius of the grinding wheel: T is the thermocouple time constant; 0 five W - maximum allowable angular frequency of rotation of the grinding wheel; m is the modulus of the gear tooth, cut on the grinding wheel, and the size of the plates of the thermocouple electrodes in the radial direction is equal to the thickness of the working zone grinding Kpyia. 2. A device pop 1, characterized in that several thermocouples are placed in the grinding wheel, the plate electrodes of which make up different angles with the rotation of the grinding wheel, on which the inserted switch with the current collector is mounted, the switch inputs connected to the thermocouple electrodes, and the output is connected via a current collector to the electronic registration unit. FTs2. -f eight FIG. 2 Me AT 4tf atld j tTO . D, 4t24Ij