# US 4,395,076 A · Bearing design for drill bit

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- Number: US 4,395,076 A
- Document ID: US4395076A
- Status: Granted
- Kind: A
- Application number: 06/320,185
- Filed: 1981-11-12
- Granted: 1983-07-26
- Earliest claimed: 1981-11-12
- Inventors: Daniel R. Sabre
- Web page: https://patentgrep.com/patent/US4395076A

## CPC

- E21B 10/22: characterised by bearing, lubrication or sealing details
- F16C 17/26: Systems consisting of a plurality of sliding-contact bearings
- F16C 2352/00: Apparatus for drilling
- E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- F16C: SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS

## Abstract

A bearing construction for a rotary earth boring drill bit is constructed of a bearing journal and a cutter rotatively mounted on the bearing journal, the bearing journal having a generally cone-shaped bearing wall formed by a plurality of steps comprised of a pair of adjacent walls joined at an apex having an acute included angle, and the cutter having a bearing wall formed with a plurality of steps mating in bearing contact with the steps of the bearing journal.

## Claims

### Claim 1

A rotary earth boring drill bit comprising
a bit body having at least one apron,
a bearing journal extending from said apron, and
a rotary cone cutter rotatively mounted on said bearing journal,
said bearing journal having a generally cone-shaped bearing wall formed by a plurality of steps extending along said bearing wall,
each of said steps comprising a pair of adjacent walls joined at an apex having an acute included angle,
said cutter having a bearing wall cooperating with said bearing wall of said bearing journal and formed with a plurality of steps mating in bearing contact with said steps of said bearing journal.

### Claim 2 (depends on 1)

A drill bit according to claim 1 wherein said apex included angle of said steps is of a size such that wear will be evenly distributed throughout the bearing surfaces.

### Claim 3 (depends on 2)

A drill bit according to claim 2 wherein said apex included angle is approximately forty-five degrees.

### Claim 4 (depends on 1)

A drill bit according to claim 1 wherein each of said steps of said journal bearing wall is comprised of a cylindrical wall and a conical wall concentric with the central longitudinal axis of said bearing journal.

### Claim 5 (depends on 4)

A drill bit according to claim 4 wherein each of said steps of said cutter is comprised of a cylindrical wall and a conical wall concentric with the central longitudinal axis of said bearing journal.

### Claim 6 (depends on 5)

A drill bit according to claim 5 wherein said apex included angle of each of said steps is approximately forty-five degrees.

### Claim 7 (depends on 5)

A drill bit according to claim 5 wherein said cylindrical and conical walls have about the same width.

### Claim 8 (depends on 1)

A drill bit according to claim 1 including means for minimizing the abrasive effect of debris formed at the bearing wall region including a plurality of grooves spaced circumferentially around each of said walls forming said steps for capturing the debris promptly after it is formed to render it harmless.

### Claim 9 (depends on 7)

A drill bit according to claim 7 wherein the spacing of said grooves is such that at any mating pair of walls no more than one pair of grooves will be aligned at any one time as said cutter rotates about said journal.