Patent ID: 8757631

Claim:
A mechanical seal device comprising: a rotational ring installed on a rotary shaft to integrally rotate with the rotary shaft and formed with a sealing surface on at least one of its surfaces in an axial direction; a stationary ring formed with a sealing surface to sealingly contact and slide with said sealing surface of said rotational ring; a rotational ring fixing portion for fixing said rotational ring to said rotary shaft; and a cover portion for containing said rotational ring and said stationary ring and for supporting said stationary ring so as to press the stationary ring axially in a direction of said rotational ring, wherein: said rotational ring fixing portion comprises a sleeve fixed on a surrounding surface of said rotary shaft, the sleeve having a rotational ring latching surface for latching together said rotational ring axially from outside or inside, and a through-bore in a radial direction for inserting a knock pin; and a rotational ring fixing collar fitted into said sleeve and arranged on axially inside or outside of the sleeve, the rotational ring fixing collar having a rotational ring latching surface for latching together said rotational ring from an opposing direction of said rotational ring latching surface of said sleeve, and a through-bore for inserting a knock pin in a radial direction communicating to said through-bore of said sleeve when the collar is fitted into said sleeve; and said rotational ring is axially sandwiched by said rotational ring latching surface of said sleeve and said rotational ring latching surface of said rotational ring fixing collar, and is fixed to said sleeve and said rotational ring fixing collar in a circumferential direction by engaging a knock pin inserted through said through-bores communicated with each other from an inner circumference side to a concave portion formed on the rotational ring.