Roller bit

Abstract

The invention relates to the technical field of drilling tools, in particular to a roller bit. The roller bit comprises a gear shaft hole, a palm shaft, steel locating balls, a sealing system and an oil storage and compensatory pressure balance system, wherein the steel locating balls are arranged between a gear and a steel ball locking groove of the palm shaft and used for locking the gear and the palm shaft, the palm shaft is composed of a large shaft and a small shaft, the upper portion of the large shaft is provided with a thrust surface, the small shaft is fixed on the thrust surface, the thrust surface and the side face of the large shaft are connected into a whole through an externally protruding arc surface, the radian of the externally protruding arc surface is identical to that of a well bottom, and the externally protruding arc surface is parallel to a well bottom angle. By means of the structure, the situation that a bearing bears force locally can be reduced, and the bit operates stably at high speed. The force bearing area of the sliding bearing is increased, so that the area of an oil film of lubricating oil is increased, the roller bit can be better adapted to directional drilling under high bit pressure and a high-temperature environment, and the requirement for the sliding bearing of the small or ultra-small roller bit can be met.

Description

technical field [0001] The invention relates to the technical field of drilling tools, in particular to a roller cone bit. Background technique [0002] The roller cone bit is a tool for breaking rocks in the earth's crust, and is widely used in oil, natural gas drilling and other mining drilling and other fields. With the further development of petroleum resources, the number of oil wells that can be exploited by conventional drilling is decreasing, and the difficulty of extraction is becoming more and more difficult. More and more oil wells are developed by unconventional drilling. The proportion of special craft wells such as horizontal wells and branch wells in oil production is increasing, so that there are more opportunities to use downhole power drilling tools for a longer time. It is more and more widely used, and its characteristic is that the drill bit speed has been greatly improved, which has exceeded 2-3 times that of the original rotary table drilling, reachin...

AI Technical Summary

Problems solved by technology

Further theoretical research and a large number of experiments show that the initial damage of the bearing during the operation of the bearing is mainly due to the rupture of the bearing lubricating grease oil film, the bearing loses grease lubrication, and the dry friction of the bearing generates high temperature, which causes the sealing system to fail. Fast-failing drill bits are scrapped

The cracking of the bearing lubricating grease oil film is mainly due to the small bearing surface of the bearing, resulting in a small lubricating grease film surface, and the unsteady operation of the drill bit, which leads to the rupture of the lubricating oil film due to point contact with the bearing stress surface.

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