Fixed cutting structure-composite cone drill bit

Abstract

A fixed cutting structure-composite cone drill bit includes a drill bit body, a fixed cutting structure, and at least one cone. The cone and the fixed cutting structure are disposed on the drill bit body. The cone is rotatably connected to the drill bit body by means of a bearing structure. The distance from the outermost tooth or back cone of the at least one cone to the front side surface of the fixed cutting structure La≤πR/3, and the distance from the outermost tooth or back cone of the at least one cone to the rear side surface of the fixed cutting structure Lb≤πR/3. In the composite drill bit, the distance from the cone to the front/rear side surface of the fixed cutting structure is short, the gap between the cone and the fixed cutting structure is small, transition between cutting structure is smooth.

Claims

1. A fixed cutting structure-composite cone drill bit, comprising: a bit body that has an end surface that is circular in shape; a first fixed blade extending across a center of the end surface of the bit body; a second fixed blade and a third fixed blade disposed on each side of the first fixed blade without contacting the first fixed blade, respectively, wherein each of the first fixed blade, the second fixed blade, and the third fixed blade comprises a plurality of cutters installed thereon; and a first roller cone and a second roller cone disposed on the end surface of the bit body, wherein the first roller is disposed between the first fixed blade and the second fixed blade and the second roller is disposed between the first fixed blade and the third fixed blade, and each of the first roller cone and the second roller cone is connected to the bit body through a bearing structure to form a rotary connection, wherein a distance La between an outermost tooth or a back surface of the first roller cone and a front side surface of the second fixed blade is less than or equal to πR/3 so that La≤πR/3, at least the distance Lb from the outermost tooth or a back surface of the first roller cone to a rear side surface of the first fixed blade is less than or equal to πR/3 so that Lb≤πR/3, R is the radius of the drill, and wherein an apex of each of the first roller cone and the second roller cone points inwardly to a center of the drill bit.

2. The fixed cutting structure-composite cone drill bit according to claim 1, wherein the distance La is less than or equal to πR/4.

3. The fixed cutting structure-composite cone drill bit according to claim 1, wherein the distance La is less than or equal to πR/5.

4. The fixed cutting structure-composite cone drill bit according to claim 1, wherein a cutting profile of the second fixed blade or the third fixed blade does not extend to the center of the drill bit.

5. The fixed cutting structure-composite cone drill bit according to claim 4, wherein the cutting profile of the second fixed blade or the third fixed blade resides in an area outside ⅓ of the radius of the drill bit.

6. The fixed cutting structure-composite cone drill bit according to claim 5, wherein the cutting profile of the second fixed blade or the third fixed blade resides in an area outside ½ of the radius of the drill bit.

7. The fixed cutting structure-composite cone drill bit according to claim 6, wherein the cutting profile of the second fixed blade or the third fixed blade resides in an area outside ⅔ of the radius of the drill bit.

8. The fixed cutting structure-composite cone drill bit according to claim 7, wherein the cutting profile of the second fixed blade or the third fixed blade resides in an area outside 80% of the radius of the drill bit.

9. The fixed cutting structure-composite cone drill bit according to claim 1, wherein a water hole is provided between the cone and the fixed cutting structure.

10. The fixed cutting structure-composite cone drill bit according to claim 1, wherein, during drilling, Hall an outer row of the gauge teeth of each of the first roller cone and the second roller cone are operable to maintain gauge.

Description

DESCRIPTION OF ATTACHED FIGURES

(1) FIG. 1 is a top view schematic diagram of the structure of the drill bit when implementing case 1 and case 2 of this invention. The top view is the diagram from the cutting structure of the bit to the rear end of the bit along the drill bit axis.

(2) FIG. 2 is a schematic structural diagram of a general view of the drill bit when implementing cases 1 and 2 of this invention.

REFERENCE SIGNS

(3) 1—drill bit body; 2—fixed cutting structure; 21—front side surface; 22—rear side surface; 3—the cone; 31—outermost tooth; 32—back cone; 4—nozzle.

SPECIFIC IMPLEMENTATION METHODS

(4) The following non-limiting cases serve to illustrate the invention.

(5) Case 1:

(6) Referring to FIG. 1 and FIG. 2, a fixed cutting structure-composite cone drill bit includes a bit body 1, a fixed cutting structure 2 and at least one cone 3. The cone 3 and the fixed cutting structure 2 are disposed on the bit body 1. The cone 3 forms a rotational connection with the bit body 1 through a bearing structure, and the distance La from the outermost tooth (or outermost row of the tooth) 31 or back cone 32 of at least one cone to the front side surface 21 of the fixed cutting structure 2 is less than or equal to πR/3, that is, La πR/3, there is at least one outermost tooth (or outermost row of the tooth) 31 or back cone 32 of the cone. And the distance Lb from the rear side surface 22 of the fixed cutting structure 2 is less than or equal to πR/3, that is, Lb yπR/3 (R is the radius of the drill). As a further option, the distance La between the outermost tooth 31 or back cone 32 of the cone 3 and the font side surface 21 of the fixed cutting structure 2 is less than or equal to πR/4 (La≤πR/4), and less than or equal to πR/5 (La≤πR/S), less than or equal to πR/6 (La≤πR/6).

(7) Preferably, the distance Lb between the outermost tooth 31 or back cone 32 of the cone 3 and the rear side surface 22 of the fixed cutting structure 2 is less than or equal to πR/4 (Lb≤πR/4), and less than or equal to πR/5 (Lb≤πR/), less than or equal to πR/6 (Lb≤πR/6).

(8) As an option, the fixed cutting structure 2 is provided with fixed cutting teeth, and the fixed cutting teeth may be PDC cutters, PDC teeth, impregnated diamond bit teeth (or blocks), cubic boron carbide, ceramic teeth, hard alloy teeth, one or more of the composite teeth made of polycrystalline diamond and impregnated diamond.

(9) As an option, the distance from the front side surface 21 to the outermost tooth (or outermost mw of the gauge teeth) 31 or back cone 32 of the cone is less than or equal to πR/3, πR/4, πR/5 or 7πR/6. The cutting profile of the cutting structure 2 does not extend to the center of the drill bit.

(10) As an option, the cutting profile of the fixed cutting structure whose profile does not extend to the center of the drill bit is in an area outside ⅓ of the radius of the drill bit. As a further option, the cutting contour of the fixed cutting structure whose contour does not extend to the center of the drill bit is in the area outside ½ of the drill bit radius; in the area outside ⅔ of the drill bit radius; in the area outside 80% of the drill radius.

(11) Case 2:

(12) Basically, this case is the same as Case 1. Referring to FIG. 2, the difference is that a water hole 4 is provided between the cone 3 and the fixed cutting structure 2. As an option, a water hole is provided between the cone 3 and the front side surface 21 of the fixed cutting structure 2 or (and) a water hole is provided between the cone 3 and the rear side surface 22 of the fixed cutting structure 2. A water hole 4 is arranged between the cone 3 and the fixed cutting structure 2 to facilitate the migration and cleaning of the cuttings generated on the cone 3 and the fixed cutting structure 2, as well as the cooling of the cutting structure. As an option, a nozzle 4 is provided in the water hole. As a further option, a fixed nozzle may be provided on the water hole 4. As another option, the nozzle 4 in the water hole is detachable (movable nozzle).

(13) Case 3:

(14) Basically, this case is the same as Case 1, and the difference is that the outer row of the gauge teeth 31 or (and) the back cone 32 of the cone 3 participates in the gauge protection. The outer row of the gauge teeth 31 or (and) the back cone 32 of the composite drill bit participates in the gauge protection. The drill has more gauge and gauge positioning points in the circumferential direction, and the impact and vibration during the rock-breaking transition between the bit cutting structures are smaller. The better the working stability of the drill bit, the better the orientation performance, and the longer the service life.

(15) The above descriptions are only preferred cases of the present invention and are not intended to limit this invention. Any modification, equivalent replacement, and improvement made within the spirit and principle of this invention shall be included in the scope of protection of this invention.