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GB1563533A - Drill bit - Google Patents

Drill bit Download PDF

Info

Publication number
GB1563533A
GB1563533A GB15169/77A GB1516977A GB1563533A GB 1563533 A GB1563533 A GB 1563533A GB 15169/77 A GB15169/77 A GB 15169/77A GB 1516977 A GB1516977 A GB 1516977A GB 1563533 A GB1563533 A GB 1563533A
Authority
GB
United Kingdom
Prior art keywords
annular
duct
bearing
drill bit
elements
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
GB15169/77A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
SKF Industrial Trading and Development Co BV
Original Assignee
SKF Industrial Trading and Development Co BV
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by SKF Industrial Trading and Development Co BV filed Critical SKF Industrial Trading and Development Co BV
Publication of GB1563533A publication Critical patent/GB1563533A/en
Expired legal-status Critical Current

Links

Classifications

    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B10/00—Drill bits
    • E21B10/08—Roller bits
    • E21B10/22—Roller bits characterised by bearing, lubrication or sealing details
    • E21B10/24—Roller bits characterised by bearing, lubrication or sealing details characterised by lubricating details
    • E21B10/246—Roller bits characterised by bearing, lubrication or sealing details characterised by lubricating details with pumping means for feeding lubricant
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B10/00—Drill bits
    • E21B10/08—Roller bits
    • E21B10/20—Roller bits characterised by detachable or adjustable parts, e.g. legs or axles
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B10/00—Drill bits
    • E21B10/08—Roller bits
    • E21B10/22—Roller bits characterised by bearing, lubrication or sealing details
    • E21B10/24—Roller bits characterised by bearing, lubrication or sealing details characterised by lubricating details

Landscapes

  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Mining & Mineral Resources (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Environmental & Geological Engineering (AREA)
  • Fluid Mechanics (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Earth Drilling (AREA)
  • Rolling Contact Bearings (AREA)

Description

(54) DRILL BIT (71) We, THE SKF INDUSTRIAI. TRAD ING & DEVELOPMENT COMPANY BV, a Company organised and existing under the laws of the Kingdom of the Netherlands, of P.O. Box 50, Nieuwegien, The Netherlands, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a drill bit.
According to the invention a drill bit comprises a body and a conical cutting element attached to the body and rotatable with respect to the body, the element having a central shaft defined by an annular recess in the base of the element, an annular portion, fixed with respect to the body and extending into the recess, bearing elements arranged between the annular portion and the central shaft, an annular gap open to the outside of the bit and extending between the outer surface of the annular portion and the outer surface of the annular recess, and a passage extending through the body and opening into the annular gap, between the bearing elements and the opening of the gap, for the discharge of fluid through the annular gap.
The annular portion may be part of an element detachably secured to the body, and the passage may comprise a first duct extending from the annular gap through the detachable element to the outside of the bit, and a second duct extending from the first duc to an open chamber in the body.
The passage may open into an annular duct between the annular portion and the outer surface of the annular recess.
The annular duct may comprise a circumferential recess in the outer surface of the annular portion and a corresponding recess in the outer surface of the annular recess.
A series of rolling elements may be located in the annular duct, the rolling bearing thus formed locating the conical cutting ele ment axially on the body.
The annular gap may communicate with the bearing elements between the central shaft and the annular portion and thence with a pressure equalising chamber.
The pressure equalising chamber may comprise a duct in the detachable element opening to the outside and a resilient wall extending across the duct.
An annular seal may be located in the annular gap between the bearing elements and the opening of the passage into the annular gap.
Lubricant may be contained between the annular seal and the resilient wall of the pressure equalising chamber.
The bearing elements may comprise two rows of rolling elements rolling on raceways on the central shaft and the annular portion.
The bearing elements may comprise elements of a plain bearing.
The mean diameter of the rolling bearing may be substantially equal to the external diameter of the annular portion.
The mean diameter of the bearing between the central shaft and the annular portion may be less than the mean diameter of the rolling bearing.
An embodiment of the invention will now be described by way of example with reference to the accompanying drawing, which is an axial section of part of a drill bit.
A drill bit 1 comprises a body 2 which is screw-threaded at the top 3 for connection to a string of pipes. Attached to the body 2 are a plurality of conical cutting elements, only one of which, 16 is shown. Conical cutting element 16 is rotatable with respect to the body 2 and has a central shaft 15 defined by an annular recess in the base of the cutting element 16. An annular portion 13, fixed with respect to the body 2, extends into the annular recess, and bearing elements 14 are arranged between the annular portion 13 and the central shaft 15 Between the outer surface of the annular portion 13 and the annular recess in the cutting element 16 is an annular gap 17 which is open to the outside of the bit 1.
Annular portion 13 is fixed to and forms part of an element 6. Fork legs, only one of which 7, is shown, extend one on each side of element 6 and a pin 8 extends through the legs 7 and the element 6, detachably securing element 6 to the bit body 2.
A passage extends through the body 2 and opens into the annular gap 17, between the bearing elements 14 and the opening of the gap 17 to the outside, for the discharge of fluid through the annular gap 17. The passage comprises a first duct 9, which extends from the annular gap 17 through the annular portion 13 through the detachable element 6 to the outside of the bit 1, and a second duct 5, which extends from duct 9 through the detachable 6 to an open chamber 4 in the body 2.
Duct 19 opens into an annular duct 12, which duct 12 is between the annular portion 13 and the annular recess in the base of the cutting element 16. Balls 10 or other rolling elements are located in the annular duct 12, which duct comprises a circumferential recess in the annular portion 13 and a corresponding recess in the annular recess in the cutting element 16. The rolling bearing thus formed locates the conical cutting element 16 axially on the body 2.
The balls 10 are placed in the duct 12 by being inserted through duct 9, and then a pin 11, recessed at its inner end to conform to the inner ball race or circumferential recess, is placed in the duct 9.
Annular gap 17 communicates via a gap 19 with the bearing elements 14 and thence with a pressure equalising chamber 24.
Chamber 24 comprises a duct 26 in the detachable element 6 opening to the outside from a cylindrical recess 23 at the head of shaft 15, and a resilient wall or diaphragm 25 extending across the duct 26.
In the annular gap 17 between duct 12 and bearing elements 14 is an annular seal 18.
The bearing elements 14 comprise two rows of rolling elements: a series of tapered roller elements 21 axially spaced at 20 from a series of cylindrical roller elements 22, rolling on raceways on the central shaft 15 and the annular portion 13. Other types of elements can be used as well as elements of a plain or sliding bearing.
The mean diameter of the rolling bearing 10, 12 is substantially equal to the external diameter of the annular portion 13, and the mean diameter of the bearing 13, 14. 15 is less than the mean diameter of the rolling bearing 10, 12. Thus the rolling bearing 10, 12 is located as radially outwardly of bearing 13, 14, 15 as possible: the further out the rolling bearing 10, 12 is, the more rolling elements 10 can be used and a more stable bearing obtained.
In operation, the drill bit 1 is connected to a string of pipes down which a fluid, sometimes known as drilling mud, is pumped. This fluid usually consists of water to which certain substances, held in suspension, have been added to increase the specific gravity. The fluid enters chamber 4 and leaves by a duct 27, cooling the drill bit 1 and washing away and carrying the debris of drilling to the surface by passing up the annular gap between the hole drilled and the string of pipes.
Some of the fluid (drilling mud) passes along duct 5, along duct 9, around duct 12 and is discharged through annular gap 17.
Thus a fluid seal is effected between the conical cutting element 16 and the body 2 and the intrusion of fine debris prevented.
The volume between the annular seal 18 and resilient wall 25 is packed with lubricant for the bearing elements 14, and pressure differences between the outside and the chamber 24 are equalised by flexing of the wall 25.
WHAT WE CLAIM IS: 1. A drill bit comprising a body and a conical cutting element attached to the body and rotatable with respect to the body, the element having a central shaft defined by an annular recess in the base of the element, an annular portion, fixed with respect to the body and extending into the recess, bearing elements arranged between the annular portion and the central shaft, an annular gap open to the outside of the bit and extending between the outer surface of the annular portion and the outer surface of the annular recess, and a passage extending thorugh the body and opening into the annular gap, between the bearing elements and the opening of the gap, for the discharge of fluid through the annular gap.
2. A drill bit as claimed in claim 1 wherein the annular portion is part of an element detachably secured to the body, and the passage comprises a first duct extending from the annular gap through the detachable element to the outside of the bit, and a second duct extending from the first duct to an open chamber in the body.
3. A drill bit as claimed in claim 1 or 2 wherein the passage opens into an annular duct between the annular portion and the outer surface of the annular recess.
4. A drill bit as claimed in claim 3 wherein the annular duct comprises a circumferential recess in the outer surface of the annular portion and a corresponding recess in the outer surface of the annular recess.
5. A drill bit as claimed in claim 3 or 4 wherein a series of rolling elements are located in the annular duct, the rolling bearing thus formed locating the coaxial cutting element axially on the body.
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (1)

  1. **WARNING** start of CLMS field may overlap end of DESC **.
    part of an element 6. Fork legs, only one of which 7, is shown, extend one on each side of element 6 and a pin 8 extends through the legs 7 and the element 6, detachably securing element 6 to the bit body 2.
    A passage extends through the body 2 and opens into the annular gap 17, between the bearing elements 14 and the opening of the gap 17 to the outside, for the discharge of fluid through the annular gap 17. The passage comprises a first duct 9, which extends from the annular gap 17 through the annular portion 13 through the detachable element 6 to the outside of the bit 1, and a second duct 5, which extends from duct 9 through the detachable 6 to an open chamber 4 in the body 2.
    Duct 19 opens into an annular duct 12, which duct 12 is between the annular portion 13 and the annular recess in the base of the cutting element 16. Balls 10 or other rolling elements are located in the annular duct 12, which duct comprises a circumferential recess in the annular portion 13 and a corresponding recess in the annular recess in the cutting element 16. The rolling bearing thus formed locates the conical cutting element 16 axially on the body 2.
    The balls 10 are placed in the duct 12 by being inserted through duct 9, and then a pin 11, recessed at its inner end to conform to the inner ball race or circumferential recess, is placed in the duct 9.
    Annular gap 17 communicates via a gap 19 with the bearing elements 14 and thence with a pressure equalising chamber 24.
    Chamber 24 comprises a duct 26 in the detachable element 6 opening to the outside from a cylindrical recess 23 at the head of shaft 15, and a resilient wall or diaphragm 25 extending across the duct 26.
    In the annular gap 17 between duct 12 and bearing elements 14 is an annular seal 18.
    The bearing elements 14 comprise two rows of rolling elements: a series of tapered roller elements 21 axially spaced at 20 from a series of cylindrical roller elements 22, rolling on raceways on the central shaft 15 and the annular portion 13. Other types of elements can be used as well as elements of a plain or sliding bearing.
    The mean diameter of the rolling bearing 10, 12 is substantially equal to the external diameter of the annular portion 13, and the mean diameter of the bearing 13,
    14. 15 is less than the mean diameter of the rolling bearing 10, 12. Thus the rolling bearing 10, 12 is located as radially outwardly of bearing 13, 14, 15 as possible: the further out the rolling bearing 10, 12 is, the more rolling elements 10 can be used and a more stable bearing obtained.
    In operation, the drill bit 1 is connected to a string of pipes down which a fluid, sometimes known as drilling mud, is pumped. This fluid usually consists of water to which certain substances, held in suspension, have been added to increase the specific gravity. The fluid enters chamber 4 and leaves by a duct 27, cooling the drill bit 1 and washing away and carrying the debris of drilling to the surface by passing up the annular gap between the hole drilled and the string of pipes.
    Some of the fluid (drilling mud) passes along duct 5, along duct 9, around duct 12 and is discharged through annular gap 17.
    Thus a fluid seal is effected between the conical cutting element 16 and the body 2 and the intrusion of fine debris prevented.
    The volume between the annular seal 18 and resilient wall 25 is packed with lubricant for the bearing elements 14, and pressure differences between the outside and the chamber 24 are equalised by flexing of the wall 25.
    WHAT WE CLAIM IS:
    1. A drill bit comprising a body and a conical cutting element attached to the body and rotatable with respect to the body, the element having a central shaft defined by an annular recess in the base of the element, an annular portion, fixed with respect to the body and extending into the recess, bearing elements arranged between the annular portion and the central shaft, an annular gap open to the outside of the bit and extending between the outer surface of the annular portion and the outer surface of the annular recess, and a passage extending thorugh the body and opening into the annular gap, between the bearing elements and the opening of the gap, for the discharge of fluid through the annular gap.
    2. A drill bit as claimed in claim 1 wherein the annular portion is part of an element detachably secured to the body, and the passage comprises a first duct extending from the annular gap through the detachable element to the outside of the bit, and a second duct extending from the first duct to an open chamber in the body.
    3. A drill bit as claimed in claim 1 or 2 wherein the passage opens into an annular duct between the annular portion and the outer surface of the annular recess.
    4. A drill bit as claimed in claim 3 wherein the annular duct comprises a circumferential recess in the outer surface of the annular portion and a corresponding recess in the outer surface of the annular recess.
    5. A drill bit as claimed in claim 3 or 4 wherein a series of rolling elements are located in the annular duct, the rolling bearing thus formed locating the coaxial cutting element axially on the body.
    6. A drill bit as claimed in any one of
    claims 1 to 5 wherein the annular gap communicates with the bearing elements between the central shaft and the annular portion and thence with a pressure equalising chamber.
    7. A drill bit as claimed in claims 2 and 6 wherein the pressure equalising chamber comprises a duct in the detachable element opening to the outside and a resilient wall extending across the duct.
    8. A drill bit as claimed in any one of claims 1 to 7 wherein an annular seal is located in the annular gap between the bearing elements and the opening of the passage into the annular gap.
    9. A drill bit as claimed in claim 8 when dependent upon claim 7 wherein lubricant is contained between the annular seal and the resilient wall of the pressure equalising chamber.
    10. A drill bit as claimed in any one of claims 1 to 9 wherein the bearing elements comprise two rows of rolling elements rolling on raceways on the central shaft and the annular portion.
    11. A drill bit as claimed in any one of claims 1 to 9 wherein the bearing elements comprise elements of a plain bearing.
    12. A drill bit as claimed in claim 5 wherein the mean diameter of the rolling bearing is substantially equal to the external diameter of the annular portion.
    13. A drill bit as claimed in claim 5 or 12 wherein the mean diameter of the bearing between the central shaft and the annular portion is less than the mean diameter of the rolling bearing.
    14. A drill bit substantially as hereinbefore described with reference to and as shown in the accompanying drawing.
GB15169/77A 1976-04-12 1977-04-12 Drill bit Expired GB1563533A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NLAANVRAGE7603835,A NL179409C (en) 1976-04-12 1976-04-12 DRILL CHISEL FOR ROCK.

Publications (1)

Publication Number Publication Date
GB1563533A true GB1563533A (en) 1980-03-26

Family

ID=19826003

Family Applications (1)

Application Number Title Priority Date Filing Date
GB15169/77A Expired GB1563533A (en) 1976-04-12 1977-04-12 Drill bit

Country Status (12)

Country Link
JP (1) JPS5936076B2 (en)
AU (1) AU514631B2 (en)
BR (1) BR7702233A (en)
CA (1) CA1064014A (en)
DE (1) DE2715788C2 (en)
FR (1) FR2348358A1 (en)
GB (1) GB1563533A (en)
IT (1) IT1076714B (en)
NL (1) NL179409C (en)
NO (1) NO771246L (en)
SE (1) SE433958B (en)
ZA (1) ZA772203B (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2755591C2 (en) * 1977-12-14 1985-11-07 SKF GmbH, 8720 Schweinfurt Roller chisel with conical cutting rollers
DE2824202A1 (en) * 1978-06-02 1979-12-06 Sandvik Gmbh Conical cutter roller chisel for mine working - has conical roller bearing force lines converging towards cutting roller tips

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1010406A (en) * 1909-07-15 1911-11-28 Howard Robard Hughes Roller-drill.
US1973975A (en) * 1933-07-25 1934-09-18 Anthony E Carlson Rotary rock bit construction
US2292036A (en) * 1940-06-28 1942-08-04 Chicago Pneumatic Tool Co Bearing for drill bits
US2339161A (en) * 1942-07-21 1944-01-11 Reed Roller Bit Co Cone bit construction
FR1053319A (en) * 1952-04-02 1954-02-02 Materiel De Forage Soc De Fab Mounting device for knurled tools
US2831660A (en) * 1956-04-16 1958-04-22 Nat Oil Tool Co Inc Lubricated well drill
US3307645A (en) * 1964-10-20 1967-03-07 Exxon Production Research Co Reverse bearing bit
NL179154C (en) 1975-02-17 1986-07-16 Skf Ind Trading & Dev ROTARY DRILL CHUCK.
US3921735A (en) * 1975-02-27 1975-11-25 Dresser Ind Rotary rock bit with cone mouth air screen

Also Published As

Publication number Publication date
NO771246L (en) 1977-10-13
AU2359777A (en) 1978-09-28
DE2715788C2 (en) 1986-06-26
BR7702233A (en) 1977-12-13
JPS52145302A (en) 1977-12-03
FR2348358B3 (en) 1980-01-18
NL7603835A (en) 1977-10-14
DE2715788A1 (en) 1977-10-20
ZA772203B (en) 1978-03-29
SE433958B (en) 1984-06-25
SE7703246L (en) 1977-10-13
NL179409C (en) 1986-09-01
AU514631B2 (en) 1981-02-19
JPS5936076B2 (en) 1984-09-01
FR2348358A1 (en) 1977-11-10
CA1064014A (en) 1979-10-09
IT1076714B (en) 1985-04-27
NL179409B (en) 1986-04-01

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Legal Events

Date Code Title Description
PS Patent sealed [section 19, patents act 1949]
PCNP Patent ceased through non-payment of renewal fee