UA86228C2 - Roller-cutter drill bit - Google Patents

Abstract

A roller-cutter drill bit has legs with axles on which sealed roller-cutters are mounted, with bearing supports, each of those has peripheral and end roll bearings and support slide bearing formed with the end of the axle and support toe fixed in the cavity of roller cutter at axis of rotation. To increase durability of roll bearings of the roller-cutter drill bit and to simplify design of its roller-cutter supports peripheral bearing of each support is arranged as radial spherical two-row roll bearing that is rigidly fixed on the axle near its basis, and the end bearing is arranged as radial-support hemi-spherical one-row bearing with barrel-like rollers equipped with separator.

Description

3) The factor of using a radial spherical double-row roller bearing, as the main bearing element of the ball support, reduces the technological requirements by an order of magnitude, in particular: - regarding the accuracy of manufacturing and the alignment of the working surfaces of the trunnion and the ball cavity, which are in contact with the rings of the rolling bearings of the support; - regarding the quality of hardening of the working surfaces that connect with the rings of typical rolling bearings used in the support; - regarding the technological operations of mounting and dismounting bearings and bearings during the assembly of the bit or its restoration. 4) The presence of separators in the rolling bearings of the ball support completely eliminates the possibility of physical contact and mutual friction of the rolling bodies during the operation of the bit. At the same time, the technological operations of mounting the rolling elements on the trunnion tracks are significantly simplified, in the case of using non-typical roller bearings. The presence of separators significantly reduces the heating of the bit layer supports. 5) The factor of using typical roller bearings (both standard and non-standard) in the support of the ball allows to additionally increase the load capacity of the support by more than 3095, in particular, due to the following reasons: - it is known that the load capacity of a radial spherical double-row roller bearing is 1.5-2 times greater load capacity of a radial roller bearing or a radial thrust conical roller bearing of the same size; - durability, wear resistance and elasticity of bearing rings manufactured as standard with the use of volume hardening to a hardness of НЕС 60-65, several times greater wear resistance and load capacity of the surface of the raceways of non-standard (non-typical) bearings, i.e. tracks made directly on the working surfaces of the trunnion and layers, but with the use of surface hardening, the depth of which does not exceed 3-3.5 mm. It is known that with excessive loads on the supports of the bits, local areas of the hardened surface of the trunnion tracks break off, or are pressed into the body of the trunnion, at a time when the bearing ring is only elastically deformed. That is why the end roller bearing with an inner ring, used in the support, has a greater load capacity and durability, compared to a bearing whose inner raceway is made directly on the trunnion. 6) The factor of using typical rolling bearings in the structure of the bit support makes it possible to significantly simplify, speed up and reduce the cost of technological operations for the production of a drill bit by eliminating the extremely time-consuming and expensive technological operations of manufacturing rolling tracks directly on the working surfaces of trunnions and bits. 7) The presence of radial and spiral grooves for lubrication in the design of the thrust bearing allows for the microcirculation of consistent lubricant in the contact zone of the working (thrust) ends of the trunnion and the heel, and allows the lubrication of other support bearings. As you know, in modern ball chisels, sealed containers with lubricant are placed in the jaws of the chisel.

The essence of the invention is explained by the following drawings, where:

Fig. 1 - a frontal projection of a drill bit with a section along the axis of the ball, the support of which contains a radial spherical double-row roller bearing and a single-row hemispherical roller bearing;

Fig. 2 - section along the axis of a ball, the support of which contains a radial spherical double-row roller bearing and a hemispherical single-row roller bearing with one (inner) bearing ring;

Fig. 3 and 4 - a section of the support of the sharoshka along A-A and along B-B.

The drill bit (Fig. 1) contains legs 1 with trunnions 2, on which rolling supports are mounted, each of which contains a peripheral radial double-row roller bearing 3, rigidly fixed (fixed) on the trunnion directly near the cylindrical projection 4 of the trunnion base, and the final radial- thrust hemispherical single-row roller bearing 5. Roller bearing 5 contains an inner ring 6, an outer ring 7 with a hemispherical inner raceway, barrel-shaped rollers 8 and a separator 9. The sliding thrust bearing (Fig. 2-4) contains a thrust surface 10 made on the end of the trunnion 2. The surface 10 is equipped with radial lubrication grooves 11, which are connected to the lubrication channel 12, made along the axis of the trunnion 2. In the cavity of the ball 13, along the axis of its rotation, a rigid heel 14 is fixed. The working surface 15 of the heel corresponds to the surface 10 of the trunnion and equipped with a lubrication groove 16, which is made in the form of a left-handed Archimedean spiral.

A through cover 17, equipped with a sealing device, is mounted on the cylindrical projection 4 of the base of each trunnion. The cover seals the cavity of each ball 13 and fixes the ball in the axial direction.

The version of the chisel support (Fig. 2) contains a spherical double-row roller bearing Z and an end radial thrust hemispherical single-row bearing equipped with an inner ring b, rollers 8 and a separator 9. The outer hemispherical raceway 18 of this end bearing is made directly in the cavity of the ball 13 concentrically to its axis rotation. The final radial thrust hemispherical roller bearing without an outer ring can be recommended for equipping the bearing supports of small-diameter ball bearings. Because the dimensions of the shells of such dolts do not allow roller bearings with outer rings to be mixed in the cavities of these shells. It is known that the durability and wear resistance of a roller bearing with an inner ring is several times greater than that of a bearing whose inner raceway is made directly on the surface of the trunnion, due to the following reasons: - the elasticity of the bearing ring is several times higher than the elasticity of the raceways made directly on the surface studs 2; - at the limit loads of the end bearing, the raceway of the bearing ring b elastically deforms together with the ring, reducing the load on the rollers 3, located on the lower side of the trunnion, while the raceway, which is made directly on the trunnion, is destroyed in the contact zone of the raceway with the most loaded roller.

The design of a bearing support with a peripheral radial spherical double-row roller bearing and an end single-row radial-thrust hemispherical roller bearing is the most technological and cheap, since the requirements for the accuracy of manufacturing the base surfaces on the trunnions and in the cavity of the shells for such a support are minimal, compared to the design of the bit-prototype supports.

In addition, the peripheral radial spherical double-row roller bearing is able to simultaneously perform a triple function, namely: the function of radial, thrust and lock bearings of the support.

The drill bit works as follows. The body of the bit is connected to the drilling unit of the drilling unit, the drilling unit with rotation and the specified axial load is fed to the wellbore. At the same time, drilling fluid or air is supplied to the hole under pressure through the flushing channels and nozzles of the bit. As a result of the immersion of the teeth of the hammers 13 in the surface of the hole, the balls come into mechanical contact with the rock and roll along the hole due to the rotation of the bit. At the same time, the teeth of the weapon successively hit local areas of the surface of the hole, chip and grind a certain layer of the rock. Flows of drilling fluid wash the mud from the surface of the hole and bit elements and carry this mud through the annulus to the surface of the earth.

In the process of dynamic interaction of the bit with the rock, the radial component load on the balls 13 is simultaneously perceived by two rows of rollers of the peripheral bearing Z and the final single-row hemispherical roller bearing 5, or the final bearing formed by the inner ring 6, rollers 8 with a separator 9 and a track 18 made in the cavity balls 13.

The axial component load, which acts in the direction of the periphery of the bit, is simultaneously perceived by: the inner row of bearing rollers 3, the end roller bearing 5 (or the end bearing formed by the ring 6, rollers 8 with the separator 9 and the track 18), and the sliding thrust bearing formed by the surface 10 and a thrust heel 14. The axial component of the load, which acts in the direction of the axis of rotation of the bit, is received by the peripheral row of rollers of the bearing 3.

During the operation of the bit, the consistent lubricant, which is placed in the lubrication system (not shown), connected to the lubrication channels 12, falls by gravity into the radial lubrication grooves 11 and the spiral groove 16. During the rotation of the balls 13, the left spiral groove 16 of each sliding bearing ensures the gradual movement of the lubricant in the radial grooves 11 in the direction from the channels 12 to the periphery of the support surfaces. At the same time, microcirculation of the lubricant is ensured in the contact zone of the working surfaces 10 and 15 of the sliding thrust bearing. Moreover, the radial grooves 11 provide automatic lubrication of the other support bearings and the sealing device located in each through cover 17.

Bench and full-scale tests of prototypes of drill bits, the supports of which are equipped with radial spherical double-row roller bearings, showed greater efficiency compared to serial bits, namely: - an increase in the mechanical speed of drilling wells by 1.5-2 times due to the possibility of a real increase in the axial load on chisel; - 3-5 times increase in the durability of the bearing units of the sharosh due to a significant increase in the bearing capacity of the supports and a more uniform and rational distribution of the radial load between all the roller bearings of the support; - a general increase of 3-5 times the working life of the bit due to the possibility of multiple replacement of worn-out pads and replaceable roller bearings of the pads' supports. !

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