A seal device that includes a seal portion protruding from a resilient body member in a common direction with a seal lip member. The seal portion being shorter in length and having a thickness that is thinner than the lip seal member. A gap is defined between an action diameter surface of the seal lip member and one of either a retainer portion or a ring member, wherein the seal portion contacts the other one of the retainer portion or ring member. A pressure receiving groove is defined between the seal lip member and the seal portion, and is in communication with the gap.
1. A seal device for effecting a seal between a shaft disposing a retainer portion and a ring member being inserted over said shaft and being rotatable relative to said shaft, said seal device comprising:
(a) a second seal ring having a second seal surface and being brought into seal contact with a packing and being inserted over said shaft, said packing being mounted to one member of said retainer portion or said ring member;
(b) a first seal ring having a first seal surface, a first support portion and a first outer diameter seal contact surface, said first seal ring being inserted over said shaft, said first seal surface facing against said second seal surface, said first support portion being disposed at a side opposite to said first seal surface, said first outer diameter seal contact surface being disposed on the outer circumferential surface between said first support portion and said first seal surface;
(c) a first resilient body member having a first inner circumferential seal portion at one end and a first outer circumferential seal portion at the other end, said first resilient body member applying an urging force to said first seal ring and being formed from an elastic material, said first inner circumferential seal portion matingly engaging said first support portion of said first seal ring, said first outer circumferential seal portion matingly engaging the other member of said retainer portion or said ring member;
(d) a first seal lip member protruding from said first resilient body member and having a seal contact surface sealingly contacting said first outer diameter seal contact surface of said first seal ring at an inner circumferential surface of the first seal lip member, said first seal lip member also having an action diameter surface located on an outer circumferential surface of said first seal lip member, wherein a wall thickness of a free end portion of said first seal lip member is larger than a wall thickness of a root portion of said first seal lip member, and wherein the root portion is located toward a first resilient body member side of said first seal lip member;
(e) a first seal portion protruding from said first resilient body member in a common direction as said first seal lip member protrudes, said first seal portion having a length that is shorter than a length of said first seal lip member and a thickness that is thinner than a thickness of said first lip seal member, wherein a gap is defined between said action diameter surface of said first seal lip member and the other member of said retainer portion or said ring member, said first seal portion contacting the other member of said retainer portion or said ring member; and
(f) a first pressure receiving groove defined between said first seal lip member and said first seal portion, said first pressure receiving groove being in communication with said gap.
2. The seal device as claimed in claim 1 , wherein said second seal ring has a shape symmetric relative to said first seal ring and includes a second seal surface, a second support portion and a second outer diameter seal contact surface, said second seal surface being brought into seal contact with said first seal surface, said second support portion being disposed at the opposite side to said second seal surface, said second outer diameter seal contact surface being disposed on the outer circumference surface between said second support portion and said second seal surface, wherein said packing includes a second resilient body member, a second inner circumferential seal portion and a second outer circumferential seal portion, said second inner circumferential seal portion being located at one end of said second resilient body member and mating with said second support portion of said second seal ring, said second outer circumferential seal portion being located at the other end of said second resilient body member and mating with said retainer portion, and further comprising:
a second seal lip member protruding from said second resilient body member and having a seal contact sealingly contacting said second outer diameter seal contact surface of said second seal ring at an inner circumferential surface of the second seal lip member, said second seal lip member also having an action diameter surface located on an outer circumferential surface of the second seal lip member, wherein a wall thickness of a free end portion of said second seal lip member is larger than a wall thickness of a root portion of said second seal lip member, and wherein the root portion is located toward a second resilient body member side of said second seal lip member;
a second seal portion protruding from said second resilient body member in a common direction as said second seal lip member protrudes, said second seal portion having a length shorter than a length of said second seal lip member and a thickness that is thinner than a thickness of said second lip seal member, wherein a second gap is defined between said action diameter surface of said second seal lip member and the one member of said retainer portion or said ring member, said second seal portion contacting the other member of said retainer portion or said ring member; and
a second pressure receiving groove defined between said first seal lip member and said first seal portion, said second pressure receiving groove being in communication with said second gap.