Stiffened blade for shear-type drill bit
View Patent ↗In one aspect of the invention, a drill bit comprises a steel body disposed intermediate a threaded end and a working face. The steel body comprises a plurality of steel blades disposed along an outer diameter of the body and extending radially away from an axis of rotation of the bit. A plurality of cutter elements is disposed on the plurality of steel blades and the blades each comprise a steel stiffness and a steel elastic modulus. At least one of the plurality of steel blades comprises a stiffening element and an overall stiffness at least 3.5 times greater than the steel stiffness.
1. A drill bit, comprising:
a steel body disposed intermediate a threaded end and a working face;
the steel body comprising a plurality of steel blades disposed along an outer diameter of the body and extending radially away from an axis of rotation of the bit;
a plurality of cutter elements disposed on the plurality of steel blades;
the cutting elements each comprising a sintered body of diamond bonded to a cemented metal carbide substrate at a non-planar interface;
the plurality of steel blades each comprising a steel stiffness and a steel elastic modulus;
at least one of the plurality of steel blades comprising a plurality of substantially cylindrical, carbide segments brazed behind and substantially coaxial with the plurality of cutter elements and being brazed to the substrate of the cutting elements; and
carbide backing plates are brazed to the back surface of the blade that forms part of the junk slot;
wherein the segments and backing plate together increase the stiffness of the blade by at least 3.5 times the steel stiffness.
2. The drill bit of claim 1 , wherein the carbide segment is disposed on a gauge portion of the at least one blade.
3. The drill bit of claim 1 , wherein the carbide segment is disposed on a flank portion of the at least one blade.
4. The drill bit of claim 1 , wherein the carbide segment is disposed on a nose portion of the at least one blade.
5. The drill bit of claim 1 , wherein the carbide segment is disposed on a cone portion of the at least one blade.
6. The drill bit of claim 1 , wherein a plurality of generally cylindrical metal carbide segments is disposed along substantially an entire length of the at least one blade.
7. The drill bit of claim 1 , wherein at least one of the cutter elements is attached to the at least one blade by the carbide segment.
8. The drill bit of claim 1 , wherein the carbide segment comprises an elastic modulus of at least 100 million pounds per square inch.
9. The drill bit of claim 1 , wherein the carbide segments increase the stiffness of the blade by at least 5 times the steel stiffness.
10. The drill bit of claim 1 , wherein the steel elastic modulus comprises at least 25 million pounds per square inch.