Pipe joint

1. A pipe joint coupled to a metal flexible pipe comprising:

a hollow joint main body;

a nut screwed into the joint main body by a threaded connection;

a seal member mounted inside of the joint main body; and

a retainer placed between the joint main body and the nut, wherein the retainer comprises:

a pawl portion engaged with a trough of the metal flexible pipe in a coupled state that the metal flexible pipe is coupled with the pipe joint by further screwing the nut into the joint main body; and

a retainer locking portion 1) caught and locked inside of the joint main body in the coupled state, and 2) not caught and locked inside of the joint main body when not in the coupled state, and

wherein a status of the retainer locking portion changes from a status that the retainer locking portion is not caught inside of the joint main body to a status that the retainer locking portion is caught inside of the joint main body by movement of the retainer locking portion along a screwing direction in which the nut is screwed into the joint main body by screwing the nut into the joint main body,

the retainer locking portion is caught and locked by a locking groove formed in an inner surface of the joint main body in the coupled state,

the retainer has a central axis line common with the joint main body and provides an annular appearance shape that forms at least part of an entire circumference in a circumferential direction about the central axis line,

the retainer comprises a leading end portion located on a leading end side along a screwing direction in which the nut is screwed into the joint main body and that includes the pawl portion and the retainer locking portion, and a rear end portion located on a rear end side along the screwing direction,

the retainer locking portion includes a tapered portion and a step portion, the tapered portion being tapered along the screwing direction toward the leading end, and the step portion is continuous from a rear end of the tapered portion and perpendicular to the radial direction,

the tapered portion and the step portion are formed on an outer circumference surface of the retainer, and

an outer diameter of the tapered portion gradually decreases along the screwing direction.

2. The pipe joint according to claim 1 , wherein

the locking groove is formed in an inner circumferential surface of the joint main body, and

the retainer locking portion is configured as a convex portion that is caught and locked in the locking groove in the coupled state.

3. The pipe joint according claim 2 , wherein the retainer and the nut are assembled to and integrated with each other before the nut is further screwed into the joint main body.

4. The pipe joint according claim 2 , wherein

the joint main body includes a body locking portion,

the nut includes a nut locking portion, and

the body locking portion and the nut locking portion are caught and locked by each other in the coupled state.

5. The pipe joint according to claim 2 , wherein a convex portion of the retainer is in contact with the locking groove on the joint main body in an opposite direction to the screwing direction in which the nut is screwed into the joint main body in the coupled state.

6. The pipe joint according to claim 1 , wherein the retainer and the nut are assembled to and integrated with each other before the nut is further screwed into the joint main body.

7. The pipe joint according to claim 1 , wherein

the joint main body includes a body locking portion,

the nut includes a nut locking portion, and

the body locking portion and the nut locking portion are caught and locked by each other in the coupled state.

8. A pipe joint coupled to a metal flexible pipe comprising:

a hollow joint main body;

a nut screwed into the joint main body by a threaded connection;

a seal member mounted inside of the joint main body; and

a retainer placed between the joint main body and the nut, wherein the retainer comprises:

a pawl portion engaged with a trough of the metal flexible pipe in a coupled state that the metal flexible pipe is coupled with the pipe joint by further screwing the nut into the joint main body; and

a retainer locking portion 1) caught and locked inside of the joint main body in the coupled state, and 2) not caught and locked inside of the joint main body when not in the coupled state, and

wherein a status of the retainer locking portion changes from a status that the retainer locking portion is not caught inside of the joint main body to a status that the retainer locking portion is caught inside of the joint main body by movement of the retainer locking portion along a screwing direction in which the nut is screwed into the joint main body by screwing the nut into the joint main body, wherein

the retainer locking portion is caught and locked by a locking groove formed in an inner surface of the joint main body in the coupled state,

the retainer has a central axis line common with the joint main body and provides an annular appearance shape that forms at least part of an entire circumference in a circumferential direction about the central axis line, and

the retainer comprises: a leading end portion located on a leading end side along a screwing direction in which the nut is screwed into the joint main body and that includes the pawl portion and the retainer locking portion; a rear end portion located on a rear end side along the screwing direction;

a distance from the central axis line to an outer diameter end of the leading end portion is longer than a distance from the central axis line to an outer diameter end of the rear end portion,

the retainer locking portion includes a tapered portion and a step portion, the tapered portion being tapered along the screwing direction toward the leading end, and the step portion is continuous from a rear end of the tapered portion and perpendicular to the radial direction,

the tapered portion and the step portion are formed on an outer circumference surface of the retainer, and

an outer diameter of the tapered portion gradually decreases along the screwing direction.