| 摘要 |
FIELD: mining. ^ SUBSTANCE: invention is related to mining industry and may be used in drilling of wells with various purpose both with and without extraction of kernel in rocks of up to XI category by their drillability. Substance of invention consists in the fact that part of tool body adjacent to friction elements and serving as support element, is made with annular groove along external and internal diametre with the possibility to install hydraulic and heat insulation elements in these grooves. At the same time material of support part is material with high yield strength, for instance martensite-ageing steel, and polar torque of support part cross section twist resistance is defined from the following ratio: W=W1ä1/ä, where W1, m3 is polar torque of tool body main part cross section twist resistance; ä1 MPa is yield strength for twisting of tool body main part material, St.20; ä, MPa is yield strength for twisting of hydraulic and heat insulation support element material in tool body. ^ EFFECT: reduced drain of heat from friction heating of rocks from bottomhole zone. ^ 4 cl, 1 dwg |
