High-speed seal
AssigneeSmith International, Inc.
InventorErwin S. Oelke
Life of this patent
Estimating the term…
Abstract
The high-speed seal is a two-part metal-to-metal type seal that, in its initial application, acts as a conventional resilient O-ring. As the seal begins to operate, a separate O-ring, retained within a seal gland channel formed in the body of a primary metal seal, provides an initial seal. As the seal continues to function over a length of time, the separate O-ring retained within the seal gland in the ring wears away and metal-to-metal contact begins to be made. Thus, the seal gradually converts from a standard O-ring type of seal to a lapped-in metal-to-metal seal during operation of the bit.
Claims12
A seal apparatus for a rotary cone rock bit, said seal being positioned in a cavity formed between a journal extending from a leg of said rock bit and a rotatable cone mounted on said journal, said seal comprising:
- a metal ring, said ring having a diameter that will fit within said cavity, a peripheral surface formed by said ring subsequently serving as part of a metal-to-metal seal, an annular seal gland channel formed by said metal ring, said channel being positioned adjacent said peripheral surface,
- a resilient material partially encapsulating said metal ring, said resilient material forming an O-ring type of seal in said cavity formed between said leg of said rock bit and said rotatable cone,
- a separate seal packing ring contained within said seal gland channel in said metal ring, during initial rotation of said cone on said journal, a portion of said separate seal packing ring adjacent said metal peripheral surface eventually wears away exposing said peripheral metal surface to an adjacent cavity wall, said metal surface and said cavity wall subsequently forming a lapped sealing surface, said separate seal packing ring prevents loss of a lubricant stored within said rock bit during the time said peripheral surface of said metal ring is forming a lapped seal against said adjacent wall of said cavity.
A method wherein a metal-to-metal seal is self-lapping, said seal being so configured to fit within a seal cavity formed by a bearing assembly, said seal retains lubricant surrounding bearing surfaces within said bearing assembly during the self-lapping process comprising the steps of:
- encapsulating partially an annular metal ring within a resilient material, a peripheral surface formed by said ring subsequently serving as part of said self-lapping metal-to-metal seal,
- inserting a separate seal packing ring into a seal gland channel formed in said metal ring adjacent and peripheral surface,
- inserting said self-lapping seal within said seal cavity, a cross section of said seal including said separate packing ring contained within said channel being larger than a cross section of said seal cavity formed by said bearing assembly, said seal being under compression when inserted within said seal cavity, said separate seal packing ring adjacent to said peripheral surface of said metal ring is positioned concentric with and outside of said peripheral surface, said separate seal packing ring prevents egress of lubricant from said bearing surfaces while said peripheral surface of said ring laps itself against an adjacent wall of said seal cavity, and
- abrading away gradually of said separate seal packing ring adjacent said metal peripheral surface as the metal-to-metal surfaces lap themselves into sealing engagement, one with the other, thereby providing a resilient seal prior to a lapped metal-to-metal seal during operation of said bearing assembly.
Dependencies are inferred from the claim text.