WO2014080372A1

WO2014080372A1 - Rolling cone earth boring bits and its manufacturing method

Info

Publication number: WO2014080372A1
Application number: PCT/IB2013/060361
Authority: WO
Inventors: Huimin Li
Original assignee: Huimin Li
Priority date: 2012-11-24
Filing date: 2013-11-24
Publication date: 2014-05-30

Abstract

An earth boring bit is disclosed. The earth boring bit includes a bearing system and a locking mechanical system. The bit includes a bit body having one or more bit legs(l), a bearing pin(2) having a conical bearing surface, a locking part (4,10) with a thrust face being a locking screw(4) mounted to the end of the bearing pin, a cone (3) mounted to the bearing pin (2) with conical rollers (7), the thrust face on the locking part withstanding the thrust surface on the conical rollers or bushes in one end, the thrust face on another end of the conical rollers(7) withstanding the inner thrust face of the cone and locking the cone on the bearing pin (2).

Description

ROLLING CONE EARTH BORING BITS AND ITS MANUFACTURING METHOD

Technical Field

[1] The present invention relates in general to the bearing system and the locking mechanical system of the rolling cone earth boring bits, in particular to an earth boring bit having a conical bearing including sliding bearing and roller bearing and its cone locking method and its manufacturing method.

Background Art

[2] One type of rolling cone earth boring bits for drilling oil and gas wells and other boreholes has a bit body with at least one rolling cone, typically three. Each cone is mounted on a cylindrical bearing pin that depends downward and inward from a bit leg of the bit body. Annular thrust faces are formed on the bearing pin and in the cone cavity. While the bit is drilling, the cylindrical bearing and annular thrust faces support the drill load in two vertical directions together. On the one hand, the cylindrical bearing pin and rolling cone are in different shapes, and it limits the volume of the bearing pin in the cavity of the rolling cone. On the other hand, because of the tolerances between the cylindrical portions of the cone and the bearing pin, the cone will flatten during working thus cause the bad working condition for the bearing and the seal. There are a lot of inventions did the improvements in this aspect, for example, the Chinese patent ZL91105563.0 and US patents

US004136748,US4802539,US4600064 and US20100071959Alwhich take use of screw or locking ring for locking. And this invention is the further improvement for my previous two patents 201210519957.8 and 201310250172.1.

Disclosure of Invention

Technical Problem

[3] The existing bearing system design of the rolling cone boring bit has a special

locking mechanism with which a great space of bearings is occupied while bearing little load, and the cylindrical bearing pin and rolling cone are in different shapes, which limits the volume of the bearing pin in the cavity of the rolling cone. On the other hand, because of tolerances between the cylindrical portions of the cone and the bearing pin, the cone will flatten during working thus cause the bad working condition for the bearing and the seal with the situation of flattening and wearing prematurely.

Technical Solution

[4] Conical roller bearings are designed to overcome the weaknesses of conventional cylinder shaped roller bearings and Friction bearings. Conical rollers better match the internal shape of the cone and the way a roller cone bit is used. Using Conical shaped rollers; each cone can house more rollers while each of these is about twice the length of conventional column shaped roller bearings. This yields a lower bearing load and much higher cone/shank stability. In sealed bearing designs, this inherent stability keeps the seal from flattening and wearing prematurely.

[5] It is difficult to process general bit bearing pin by boring machine, one of the

important reasons is that the locking slot on the edge of the bearing pin can not be processed by boring machine. But in this invention, there is not any locking slot on the bearing pin, so it can be processed by boring machine fast.

Advantageous Effects

[6] Conical rollers better match the internal shape of the cone and the way a roller cone bit is used. Using Conical shaped rollers; each cone can house more rollers while each of these is about twice the length of conventional column shaped roller bearings. This yields a lower bearing load and much higher cone/shank stability. In sealed bearing designs, this inherent stability keeps the seal from flattening and wearing prematurely.

[7] That the boring processing replaces the lathe processing makes the manufacturing of the bit frame more economical than it is in the way of lathe machining. Because the bit frame can be processed as a whole body but not like the conventional way to process the three pieces separately and combine them together by welding process as a final tricone bit.

Description of Drawings

[8] FIG. 1 is a vertical sectional view illustrating a portion of an earth boring bit having a conical bearing pin and conical rollers and a locking screw mounted to the end of the conical bearing pin constructed in accordance with this invention.

[9] FIG. 2 is a vertical sectional view illustrating a portion of an earth boring bit having a conical bearing pin and conical rollers and a locking nut mounted to the end of the conical bearing pin constructed in accordance with this invention.

[10] FIG. 3 is a vertical sectional view illustrating a portion of an earth boring bit having a conical bearing pin and conical rollers and a locking nut and its stud mounted to the end of the conical bearing pin constructed in accordance with this invention.

[11] FIG. 4 is a vertical sectional view illustrating a portion of an earth boring bit having a conical bearing pin and conical sliding bushes and a locking nut and its bolt mounted to the end of the conical bearing pin constructed in accordance with this invention.

[12] FIG. 5 is a front view illustrating the locking nut in accordance with this invention.

[13] FIG. 6 is a front view illustrating the detent pin in accordance with this invention.

[14] FIG. 7 is an isometric view illustrating the conical sliding bushes in accordance with this invention.

[15] FIG. 8 is a vertical sectional view illustrating a portion of an earth boring bit having a cylindrical bearing pin and a locking ring and a locking screw mounted to the end of the cylindrical bearing pin constructed in accordance with this invention.

[16] FIG. 9 is a vertical sectional view illustrating a portion of an earth boring bit having a conical bearing pin and a sliding bearing and a locking nut and its locking ring mounted to the end of the conical bearing pin constructed in accordance with this invention.

[17] FIG. 10 is a vertical sectional view illustrating a portion of boring machining for conical bearing pin of an earth boring bit on boring machine.

[18] FIG. 11 is a vertical sectional view illustrating a portion of a frame of the earth boring bit having a body and a threaded pin constructed in accordance with this invention.

Best Mode

[19] In this invention, a rolling cone boring bit has a conical bearing pin and conical rollers or sliding bushes, and a locking screw or a locking nut mounted to the end of the conical bearing pin. The locking theory of the rolling cone is as follows: the thrust face of the locking screw or locking nut withstands the small end of the conical rollers or sliding bushes, and the other big end of the conical rollers or sliding bushes withstands the inner thrust face in the rolling cone. A hexagon screwdriver can be used to fasten the locking nut or locking screw through the hole in the center of the conical bearing pin.

[20] Referring to FIG. 3, it is the design to be regarded as a combination of locking nut

10 and double end screw 13 replacing locking screw 4 shown in FIG.l. There is a recess drive 14 at the end of double end screw 13, and others are the same as shown in FIG.2. This design has a characteristic that cone 3 will mainly shift in the axial direction of the bit body but shift little in the axial direction of conical bearing pin 2 if double end screw 13 is assembled after cone 3 has been assembled, and it provides a possibility to use an integrated bit frame with three legs to be assembled with cone 3 in the end so as to avoid the high temperature of welding the bit frame from harming the seal of bit and so on.

Mode for Invention

[21] Referring to FIG. 1, locking screw 4 is mounted to conical bearing pin 2 with screw fastening, and there is a thrust face 5 on the mushroom head of locking screw 4.

Conical rollers 7 are installed between cone 3 and conical bearing pin 2. There is an inner thrust face 6 in cone 3 restricting conical rollers 7 in the axial direction together with thrust face 5. The four parts: conical bearing pin 2, cone 3, locking screw 4 and conical rollers 7 constitute the locking mechanical system while the conical rollers 7 bear the entire load. There is a recess drive 8 at the end of locking screw 4 being used for driving it into conical bearing pin 2 with tools such as hex wrench and so on. Recess drive 8 can be designed in many shapes such as six-lobe recess drive and slot drive etc. Plug 9 is used for closure of the central hole of the conical bearing pin 2 on exterior surface of bit leg 1, and it also can be welded as conventionally. Thrust face 5 and thrust face 6 may be in sphere or roughly conical and so on.

[22] Referring to FIG. 2, locking nut 10 is mounted to conical bearing pin 2 with screw fastening, and there is a thrust face 5 on the mushroom head of locking nut 10. There are two or more slots in the end of conical bearing pin 2 holding detent pin 12 which clamps locking nut 10 by the slots in hole drive 11 of locking nut 10. FIG.5 shows the structure of locking nut 10, and it has six slots at the edge of hole drive 11 for holding detent pin 12. As described in FIG.2, hole drive 11 can be designed in many shapes. That locking nut 10 replaces locking screw 4 makes conical bearing pin 2 much stronger in small size bits.

[23] Referring to FIG. 4, the design can be regarded as the combination of locking nut

10 and locking bolt 13 replacing the combination of locking nut 10 and double end screw 13 shown in FIG.3. Recess drive 14 can be cancelled when locking bolt 13 is clamped not to turn. The bearing system shown in FIG.4 is a sliding bearing. Bush 16 has replaced conical rollers 7 as one of the locking parts and bearing parts aforementioned. The structure of bush 16 is shown in FIG.7. It is in the shape of conical segmenta and has a small thrust face 17 and big thrust face 18. Bush 16 is designed as a segmenta but not as a whole conical body so that it can be inserted in cone 3.

[24] The inventions shown in FIG.l to FIG.4 have a common feature that the locking part such as locking screw 4 or locking nut 10 must be assembled first in the assembly sequence in cone 3, followed by conical rollers 7 or bush 16 and so on, because the mushroom head of the locking part is the innermost part in the cavity of cone 3.

Sometimes the dome face of the mushroom head can be used as another thrust face to withstand the inner dome of cone 3 and share some load, in which case one side could be considered as a thrust face of the locking part mounted to the bearing pin and the other side a thrust face of the cone. And the friction torque from cone 3 to locking part will fasten the locking part screw with the right screw direction.

[25] The main idea of this invention is using locking part such as locking screw 4 or locking nut 10 to lock conical rollers 7 or bush 16 in cone 3 and lock cone 3 by means of inner thrust face 6, while conical rollers 7 or bush 16 withstand full of the load. This invention saves more space in cone 3 and has the most great and strong bearing system. The existing bearing system design of the rolling cone boring bit has a special locking mechanism which occupies a great space of bearings while bearing little load.

[26] Referring to FIG. 8, as an extention of this invention design theory, it is similar with FIG 4, the difference is that it is transformed into a piece of locking ring 19 when shorten the length of bush 16 shown in FIG 4 in axial direction. And locking ring 19 is formed from an elastic opening whole ring or two or more pieces cut from a rigid whole ring. And the sliding bearing can be replaced by conical roller bearing and so on.

[27] Referring to FIG. 9, it is similar with FIG.8 but the sliding bearing is in the shape of column, and the sliding bearing can be replaced by roller bearing and so on.

[28] The locking parts such as locking screw 4, locking nut 10 or its bolt or stud shown in FIG.l to FIG.4 can be used in the designs of locking ring shown in FIG.8 and FIG.9.

[29] There is a possibility of boring machining conical bearing pin 2 that will be faster than with lathe machining, because it is difficult to lathe machining a piece of one bit leg or 1/3 bit frame fast, before combined as a bit frame by welding

[30] Referring to FIG.10#it is a way to bore conical bearing pin 2 on boring machine.

[31] On the boring machine there is a spindle sleeve 21 in the spindle 20 and links the shank 23 with the connecting rod 22, and the shank 23 is assembled on the slide way 25, and there is a blade 24 fixed on shank 23.

[32] When the boring machine is working as: spindle 20 and the spindle sleeve 21 are turning and spindle sleeve 21 moving downward while turning, blade 24 will cut conical bearing pin 2 into the conical shape. Of course, this mechanical system can be also designed as gear rack system (not shown). It also transmits the vertical moving of spindle sleeve 21 to tilted moving of shank 23 on the slide way 25.

[33] It is difficult to process general bit bearing pin by boring machine, for the locking slot on the edge of the bearing pin can not be processed by boring machine. But in this invention shown in FIG.1-FIG4, FIG8 and FIG.9, there is not any locking slot on the bearing pin, so it can be processed by boring machine fast.

[34] That the boring processing replaces the lathe processing makes the manufacturing of bit frame more economical than it is in the way of lathe machining. Because the bit frame can be processed as whole body not like the conventional way to process the three pieces separately and combine them together by welding process as a final tricone bit. Referring to FIG.l l#the whole bit frame is divided into two parts of forgings further: the forging of bit body 26 with three bit legs 1 and the forging of threaded pin 27. After machining the forgings, the two parts will be combined by welding process to be the whole bit frame. The two forgings in this way is much easier to forge than to have only one piece forging as a whole bit frame.

Industrial Applicability

[35] The present invention relates in general to the bearing system and the locking mechanical system of the rolling cone earth boring bits for drilling oil and gas wells and other boreholes has a bit body with at least one rolling cone, typically three, and in particular to an earth boring bit having a conical bearing including sliding bearing and roller bearing and its cone locking method. These advantages make the said rolling cone earth boring bit more economical with better performance.

Sequence List Text

[36] Description 5 pages

[37] Claims lpage

[38] Abstract 1 page

[39] Drawings 3 pages

Claims

1. An earth boring bit, comprising: a bit body having one or more bit legs; a bearing pin having a conical bearing surface; a locking part with a thrust face being a locking screw or locking nut mounted to the end of the bearing pin; a cone mounted to the bearing pin with conical rollers or bushes; the thrust face on the locking part withstanding the thrust surface on the conical rollers or bushes in one end, the thrust surface on another end of the conical rollers or bushes withstanding the inner thrust face of the cone and locking the cone on the bearing pin.

2. The bit according to claim 1, wherein the conical surface of the conical bearing pin is processed by boring machining.

3. The bit according to claim 1, wherein a recess drive is at the end of the locking screw or a hole drive is in the locking nut.

4. The bit according to claim 1, wherein the bit frame is assembled with the bit body and the threaded pin by welding processing.

5. An earth boring bit, comprising: a bit body having one or more bit legs; a cone having a locking slot and one or more pieces of locking rings in this locking slot and the cone being mounted to the bearing pin with rollers or sliding bearing; a locking part with thrust face being a locking screw or locking nut mounted to the end of the bearing pin; the thrust face on the locking part withstanding the pieces of the locking rings and locking the cone on the bearing pin.

6. The bit according to claim 5, wherein the surface of the bearing pin is processed by boring machining.

7. The bit according to claim 5, wherein the recess drive is at the end of the locking screw or the hole drive is in the locking nut.

8. The bit according to claim 5, wherein the bit frame is assembled with the bit body and the threaded pin by welding processing.

9. The bit according to claim 2, wherein the boring machine has a spindle sleeve in the spindle linking the shank with the connecting rod, and the shank is assembled on the slide way.

10. The bit according to claim 5, wherein the boring machine has a spindle sleeve in the spindle linking the shank with the connecting rod, and the shank is assembled on the slide way.