Dual functioning seal for rock bits

A seal for use in a rotary cone rock bit comprising:

• an annular elastomeric seal body having a dynamic rotary seal surface for sealing against a rock bit dynamic surface and a static seal surface for sealing against a rock bit static surface, wherein the dynamic and static seal surfaces are each formed from an elastomeric material and are permanently secured to the elastomeric seal body to form a one-piece seal construction, the seal having an asymmetric axial cross-sectional geometry, wherein a contact length of a radial cross section of the seal is greater on the dynamic seal surface than on the static seal surface, and
• at least one of the dynamic and static seal surface being formed from an elastomeric material that is different than that used to form the seal body.

A seal for use in a rotary cone rock bit comprising:

• an annular elastomeric seal body having a dynamic rotary seal surface for sealing against a rock bit dynamic surface and a static seal surface for sealing against a rock bit static surface, the seal body, dynamic seal surface, and static seal surface each being formed from different elastomeric materials and being permanently secured to the elastomeric seal body to form a one-piece seal construction, the seal having an asymmetric axial cross-sectional geometry wherein a contact length of a radial cross section of the seal is greater on the dynamic seal surface than on the static seal surface.

A seal for use in a rotary cone rock bit comprising:

• an annular elastomeric seal body having a dynamic rotary seal surface for sealing against a rock bit dynamic surface and a static seal surface for sealing against a rock bit static surface, the seal body, dynamic seal surface, and static seal surface each being formed from different elastomeric materials and being permanently secured to the elastomeric seal body to form a one-piece seal construction, the elastomeric material selected to form the dynamic seal surface having a modulus of elasticity greater than that of a material selected to form the seal body, the material selected to form the static seal surface having a coefficient of friction greater than the materials used to form both the seal body and dynamic seal surface, the seal having an asymmetric axial cross-sectional geometry, wherein a contact length of a radial cross section of the seal is greater on the dynamic seal surface than on the static seal surface.

A seal for use in a rotary cone rock bit comprising:

• an annular elastomeric seal body having a dynamic rotary seal surface for sealing against a rock bit dynamic surface and a static seal surface for sealing against a rock bit static surface, the static and dynamic seal surfaces being formed from different elastomeric materials and being permanently secured to the elastomeric seal body to form a one-piece seal construction, and
• the seal having an asymmetric axial cross-sectional geometry with the dynamic seal surface having a radius of curvature greater than about one half an axial thickness of the seal body, and at least ten percent greater than a radius of curvature of the static seal surface.

A seal for use in a rotary cone rock bit comprising:

• an annular elastomeric seal body having a dynamic rotary seal surface for sealing against a rock bit dynamic surface and a static seal surface for sealing against a rock bit static surface, the seal body, dynamic seal surface, and static seal surface each being formed from different elastomeric materials and being permanently secured to the elastomeric seal body to form a one-piece seal construction, and
• the seal having an asymmetric axial cross-sectional geometry with the dynamic seal surface having a radius of curvature greater than about one half an axial thickness of the seal body, and at least ten percent greater than a radius of curvature of the static seal surface.

A seal for use in a rotary cone rock bit comprising:

• an annular elastomeric seal body having a dynamic rotary seal surface for sealing against a rock bit dynamic surface and a static seal surface for sealing against a rock bit static surface, the seal body, dynamic seal surface, and static seal surface each being formed from different elastomeric materials and being permanently secured to the elastomeric seal body to form a one-piece seal construction, the elastomeric material selected to form the dynamic seal surface having a modulus of elasticity greater than that of a material selected to form the seal body, the material selected to form the static seal surface having a coefficient of friction greater than the materials used to form both the seal body and dynamic seal surface, and the seal having an asymmetric axial cross-sectional geometry with the dynamic seal surface having a radius of curvature greater than about one half an axial thickness of the seal body, and at least ten percent greater than a radius of curvature of the static seal surface.

A seal for use in a rotary cone rock bit including a bit body and at least one cutter cone mounted for rotation on the bit body, the seal comprising:

• an annular elastomeric seal body forming a lubricant seal between the cone and bit body, the seal body having a dynamic rotary seal surface for sealing against a rock bit dynamic surface and a static seal surface for sealing against a rock bit static surface, the dynamic and static seal surfaces being permanently secured to the seal body to form a one-piece seal construction,
• the seal body having an asymmetric axial cross-sectional geometry with the dynamic seal surface having a radius of curvature greater than about one half of an axial thickness of the seal body, and at least ten percent greater than a radius of curvature of the static seal surface,
• the dynamic seal surface formed from an elastomeric material different than that of the static seal surface and having a durometer Shore A hardness of at least five points higher than the static seal surface.