Patent ID: 6676132
Filing Date: 2004-01-13
Classification: F16C,F16J

Abstract:
A seal arrangement comprising:a rotary member; a chamber having a fixed member disposed about said rotary member; said chamber defining a vacuum space where the pressure is equal to or less than 10âˆ’4 Pa; said chamber being disposed in an atmosphere space at atmospheric pressure; a seal member providing a seal interface between the rotary member and the fixed member; said seal having a lip; said lip for sealing one of a clearance and a sealed portion between the rotary member and the seal; said lip including a main lip and an auxiliary lip; a cross-sectional shape of an upper half of said main lip being a generally triangular shape directed toward a rotary member side and having the axial contact width gradually reduced; an axial contact width of said main lip W0 with respect to the rotary member being within a range of 0.2 mm&lE;W0&lE;2.0 mm; the main lip being adjacent the atmosphere space; the auxiliary lip being adjacent the vacuum space; said lip being constituted to be coated on an annular core metal attached to the fixed member, and an inner peripheral portion of the lip including an elastic element sliding on and contacting with the rotary member; and a hardness of a slide-contact portion of said lip with respect to the rotary member being set at a durometer hardness of 30 to 90, wherein said main lip has the axial contact width equal to or larger than a width necessary to secure minimum sealing performance with respect to said sealed portion and equal to or smaller than a width with which sliding resistance against the rotary member becomes a permissible upper limit so that a gaseous seal is provided between the vacuum space and the atmosphere space.