Abstract: A sealing device has a seal ring in a groove having a step, a first backup ring at the step in the groove, and a second backup ring, in the groove, between both rings offset from the step. The first backup ring includes a bottom-surface-side peripheral surface facing the step's bottom surface, an end surface facing the step's non-sealed-fluid-side side surface, a peripheral surface adjacent to the other member and facing the other member, and a slope facing the second backup ring. The length of the bottom-surface-side peripheral surface is equal to or smaller than the length of the bottom surface of the step. The second backup ring includes a peripheral surface facing the bottom surface of the groove, an end surface facing the non-sealed-fluid-side side surface of the groove, a slope facing the slope of the first backup ring, and a sealed-fluid-side end surface facing the seal ring.

Abstract: A sealing device in which diameter expansion of an inserted first back-up ring is suppressed. The sealing device includes a seal ring mounted in a rectangular mounting groove, the first back-up ring, and a second back-up ring. The first back-up ring has an end surface contacting an opposing-sealing-fluid-side side surface of the mounting groove. The second back-up ring has an end surface contacting the seal ring. A contact surface in an inner peripheral end of second back-up ring is perpendicular to the axis to contact an opposing-sealing-fluid-side side surface of the mounting groove. The inner diameter of the first back-up ring is set to be larger than the outer diameter of the contact surface portion of the second back-up ring, and the outer diameter of the first back-up ring is set to be smaller than the inner diameter of a housing.

Abstract: A sealing device has a seal ring in a groove having a step, a first backup ring at the step in the groove, and a second backup ring, in the groove, between both rings offset from the step. The first backup ring includes a bottom-surface-side peripheral surface facing the step's bottom surface, an end surface facing the step's non-sealed-fluid-side side surface, a peripheral surface adjacent to the other member and facing the other member, and a slope facing the second backup ring. The length of the bottom-surface-side peripheral surface is equal to or smaller than the length of the bottom surface of the step. The second backup ring includes a peripheral surface facing the bottom surface of the groove, an end surface facing the non-sealed-fluid-side side surface of the groove, a slope facing the slope of the first backup ring, and a sealed-fluid-side end surface facing the seal ring.

Abstract: A sealing device has a seal ring, a first backup ring and a second backup ring. The first backup ring is formed into a triangular cross section while having an axially vertical end surface portion, a cylindrical peripheral surface portion, and an inclined surface portion intersecting the end surface portion and the peripheral surface portion. The second backup ring is formed into a triangular cross section while having an axially vertical end surface portion, a cylindrical peripheral surface portion, and an inclined surface portion in correspondence to the inclined surface portion of the first backup ring. A cut portion is provided in a corner portion where the end surface portion and the inclined surface portion in the first backup ring intersect, and a corner portion where the peripheral surface portion and the inclined surface portion in the second backup ring intersect.

Abstract: A sealing device in which diameter expansion of an inserted first back-up ring is suppressed. The sealing device includes a seal ring mounted in a rectangular mounting groove, the first back-up ring, and a second back-up ring. The first back-up ring has an end surface contacting an opposing-sealing-fluid-side side surface of the mounting groove. The second back-up ring has an end surface contacting the seal ring. A contact surface in an inner peripheral end of second back-up ring is perpendicular to the axis to contact an opposing-sealing-fluid-side side surface of the mounting groove. The inner diameter of the first back-up ring is set to be larger than the outer diameter of the contact surface portion of the second back-up ring, and the outer diameter of the first back-up ring is set to be smaller than the inner diameter of a housing.

Abstract: A sealing structure suppresses possible damage to a seal ring because of a backup ring. The sealing structure is characterized in that a cut portion 150 that is cut in a planar shape is formed in a backup ring 100 at one position in a circumferential direction, the cut portion 150 is configured such that a cut surface 153 is oblique to a central axis of the backup ring 100, an acute angle of angles between a surface on the high pressure side of the backup ring 100 and the cut surface 153 is set to not less than 15° and not more than 30°, and the backup ring 100 is formed of a resin material having Rockwell hardness of 100 or less, durometer hardness of 70 or less, and elastic modulus of 1.0 GPa or less.

Abstract: A sealing structure suppresses possible damage to a seal ring because of a backup ring. The sealing structure is characterized in that a cut portion 150 that is cut in a planar shape is formed in a backup ring 100 at one position in a circumferential direction, the cut portion 150 is configured such that a cut surface 153 is oblique to a central axis of the backup ring 100, an acute angle of angles between a surface on the high pressure side of the backup ring 100 and the cut surface 153 is set to not less than 15° and not more than 30°, and the backup ring 100 is formed of a resin material having Rockwell hardness of 100 or less, durometer hardness of 70 or less, and elastic modulus of 1.0 GPa or less.

Abstract: A sealing device has a seal ring, a first backup ring and a second backup ring. The first backup ring is formed into a triangular cross section while having an axially vertical end surface portion, a cylindrical peripheral surface portion, and an inclined surface portion intersecting the end surface portion and the peripheral surface portion. The second backup ring is formed into a triangular cross section while having an axially vertical end surface portion, a cylindrical peripheral surface portion, and an inclined surface portion in correspondence to the inclined surface portion of the first backup ring. A cut portion is provided in a corner portion where the end surface portion and the inclined surface portion in the first backup ring intersect, and a corner portion where the peripheral surface portion and the inclined surface portion in the second backup ring intersect.

Abstract: In a water-proof structure for an opening of a device case, which includes a packing installed in a peripheral groove around a cover and compressed between the inner periphery of the opening and the groove when the cover is inserted into the opening, the packing is configured to have a flat contact surface in contact with the bottom of the groove and have a cross section having a width larger than the height, and the cross section of the packing also has a flat bottom or an inner side to fit the groove bottom that is also flat in a cross section while the outer side has a convex shape so that the whole cross section has a D-shaped form, in order to prevent degraded sealing capability or improper installation due to twist of the packing in the groove.