Shaft sealing structure and primary coolant circulation pump

A shaft sealing structure for a rotation shaft, comprising:

• a sealing ring having a ring shape in which a part is removed in a circumferential direction so that the sealing ring has ends formed by removal of the part, wherein the ends abutting each other are continuous in the circumferential direction when the sealing ring is reduced in diameter to a radially inner side, and the sealing ring is provided along the circumferential direction of the rotation shaft so as to be contactable with an outer peripheral surface of the rotation shaft;
• a pressing member configured to be movable between a pressing position at which the pressing member presses the sealing ring to the radially inner side and a retracted position at which the pressing member is retracted from the pressing position;
• an elastic member configured to bias the pressing member toward the pressing position by elastic force;
• a support member configured to support the pressing member at the retracted position against the elastic force of the elastic member, and to allow the pressing member to move to the pressing position at a predetermined temperature or higher;
• and
• a communicating portion configured to communicate between an outer circumferential portion of the rotation shaft and a surface of the support member so that a fluid flows from the outer circumferential portion of the rotation shaft to the surface of the support member,
• wherein the support member is disposed in a space defined by a top surface of the pressing member and an outer surface of the sealing ring,
• wherein the communicating portion terminates at the surface of the support member,
• wherein the support member has recesses and protrusions formed on a surface thereof, and
• at least one of the sealing ring and the pressing member has recesses and protrusions formed on a surface thereof and engaged with the recesses and protrusions formed on the support member.

A shaft sealing structure for a rotation shaft, comprising:

• a sealing ring having a ring shape in which a part is removed in a circumferential direction so that the sealing ring has ends formed by removal of the part, wherein the ends abutting each other are continuous in the circumferential direction when the sealing ring is reduced in diameter to a radially inner side, and the sealing ring is provided along the circumferential direction of the rotation shaft so as to be contactable with an outer peripheral surface of the rotation shaft;
• a pressing member configured to be movable between a pressing position at which the pressing member presses the sealing ring to the radially inner side and a retracted position at which the pressing member is retracted from the pressing position;
• an elastic member configured to bias the pressing member toward the pressing position by elastic force;
• a support member configured to support the pressing member at the retracted position against the elastic force of the elastic member, and to allow the pressing member to move to the pressing position at a predetermined temperature or higher;
• and
• a communicating portion configured to communicate between an outer circumferential portion of the rotation shaft and a surface of the support member so that a fluid flows from the outer circumferential portion of the rotation shaft to the surface of the support member,
• wherein the support member is disposed in a space defined by a top surface of the pressing member and an outer surface of the sealing ring,
• wherein the communicating portion terminates at the surface of the support member,
• wherein the support member includes a plate-shaped member configured to support the pressing member located at the retracted position against a movement direction and to be softened at a predetermined temperature or higher, and
• the plate-shaped member is formed by being divided in the circumferential direction by a plurality of cutting grooves extending in the movement direction of the pressing member.

A shaft sealing structure for a rotation shaft, comprising:

• a sealing ring having a ring shape in which a part is removed in a circumferential direction so that the sealing ring has ends formed by removal of the part, wherein the ends abutting each other are continuous in the circumferential direction when the sealing ring is reduced in diameter to a radially inner side, and the sealing ring is provided along the circumferential direction of the rotation shaft so as to be contactable with an outer peripheral surface of the rotation shaft;
• a pressing member configured to be movable between a pressing position at which the pressing member presses the sealing ring to the radially inner side and a retracted position at which the pressing member is retracted from the pressing position;
• an elastic member configured to bias the pressing member toward the pressing position by elastic force;
• a support member configured to support the pressing member at the retracted position against the elastic force of the elastic member, and to allow the pressing member to move to the pressing position at a predetermined temperature or higher;
• and
• a communicating portion configured to communicate between an outer circumferential portion of the rotation shaft and a surface of the support member so that a fluid flows from the outer circumferential portion of the rotation shaft to the surface of the support member,
• wherein the support member is disposed in a space defined by a top surface of the pressing member and an outer surface of the sealing ring,
• wherein the communicating portion terminates at the surface of the support member,
• and wherein the support member is configured to support the pressing member at the retracted position by tensile force against the elastic force of the elastic member in a manner that a fusible portion that fuses at a predetermined temperature or higher is interposed.

A shaft sealing structure for a rotation shaft, comprising:

• a sealing ring having a ring shape in which a part is removed in a circumferential direction so that the sealing ring has ends formed by removal of the part, wherein the ends abutting each other are continuous in the circumferential direction when the sealing ring is reduced in diameter to a radially inner side, and the sealing ring is provided along the circumferential direction of the rotation shaft so as to be contactable with an outer peripheral surface of the rotation shaft;
• a pressing member configured to be movable between a pressing position at which the pressing member presses the sealing ring to the radially inner side and a retracted position at which the pressing member is retracted from the pressing position;
• an elastic member configured to bias the pressing member toward the pressing position by elastic force;
• a support member configured to support the pressing member at the retracted position against the elastic force of the elastic member, and to allow the pressing member to move to the pressing position at a predetermined temperature or higher;
• and
• a communicating portion configured to communicate between an outer circumferential portion of the rotation shaft and a surface of the support member so that a fluid flows from the outer circumferential portion of the rotation shaft to the surface of the support member,
• wherein the support member is disposed in a space defined by a top surface of the pressing member and an outer surface of the sealing ring,
• wherein the communicating portion terminates at the surface of the support member,
• and wherein the support member includes a buckling member provided so as to allow the pressing member to move to the pressing position by relative movement of the support member and the pressing member in the circumferential direction, the buckling member being configured to restrict the relative movement of the support member and the pressing member in the circumferential direction at the retracted position of the pressing member and to buckle at a predetermined temperature or higher to allow the relative movement of the support member and the pressing member in the circumferential direction.

A shaft sealing structure for a rotation shaft, comprising:

• a sealing ring having a ring shape in which a part is removed in a circumferential direction so that the sealing ring has ends formed by removal of the part, wherein the ends abutting each other are continuous in the circumferential direction when the sealing ring is reduced in diameter to a radially inner side, and the sealing ring is provided along the circumferential direction of the rotation shaft so as to be contactable with an outer peripheral surface of the rotation shaft;
• a pressing member configured to be movable between a pressing position at which the pressing member presses the sealing ring to the radially inner side and a retracted position at which the pressing member is retracted from the pressing position;
• an elastic member configured to bias the pressing member toward the pressing position by elastic force;
• a support member configured to support the pressing member at the retracted position against the elastic force of the elastic member, and to allow the pressing member to move to the pressing position at a predetermined temperature or higher;
• and
• a communicating portion configured to communicate between an outer circumferential portion of the rotation shaft and a surface of the support member so that a fluid flows from the outer circumferential portion of the rotation shaft to the surface of the support member,
• wherein the support member is disposed in a space defined by a top surface of the pressing member and an outer surface of the sealing ring,
• wherein the communicating portion terminates at the surface of the support member,
• and wherein the support member includes:
• a claw-shaped member configured to support the pressing member located at the retracted position and to be softened at a predetermined temperature or higher;
• and
• an initial irregularity configured to cause the claw-shaped member to buckle so as to allow the pressing member to move to the pressing position.

A shaft sealing structure for a rotation shaft, comprising:

• a sealing ring having a ring shape in which a part is removed in a circumferential direction so that the sealing ring has ends formed by removal of the part, wherein the ends abutting each other are continuous in the circumferential direction when the sealing ring is reduced in diameter to a radially inner side, and the sealing ring is provided along the circumferential direction of the rotation shaft so as to be contactable with an outer peripheral surface of the rotation shaft;
• a pressing member configured to be movable between a pressing position at which the pressing member presses the sealing ring to the radially inner side and a retracted position at which the pressing member is retracted from the pressing position;
• an elastic member configured to bias the pressing member toward the pressing position by elastic force;
• a support member configured to support the pressing member at the retracted position against the elastic force of the elastic member, and to allow the pressing member to move to the pressing position at a predetermined temperature or higher;
• and
• a communicating portion configured to communicate between an outer circumferential portion of the rotation shaft and a surface of the support member so that a fluid flows from the outer circumferential portion of the rotation shaft to the surface of the support member,
• wherein the support member is disposed in a space defined by a top surface of the pressing member and an outer surface of the sealing ring,
• wherein the communicating portion terminates at the surface of the support member,
• and wherein the support member includes:
• a claw-shaped member configured to support the pressing member located at the retracted position and to be softened at a predetermined temperature or higher;
• and
• an expanding member configured to thermally expand at a predetermined temperature or higher to deform the claw-shaped member and allow the pressing member to move to the pressing position.