Member joining method

1. A member joining method comprising:

a placement process of arranging a first member and a second member inserted into the first member so that a gap surrounding the second member is provided between the first member and the second member, a diameter of an inner peripheral portion of a main body of the first member being less than a diameter of an outer peripheral portion of the second member, an inner diameter of the first member becoming progressively smaller from an inner peripheral portion of a tubular portion of the first member toward the inner peripheral portion of the main body;

a filling process of filling a molten resin into the gap and applying pressure to the resin so as to cause at least one member of the first member or the second member to undergo elastic deformation, the inner diameter of the first member remaining progressively smaller after the filling process; and

a pressure maintaining process of maintaining the pressure until the resin that has been filled into the gap has cured.

2. The member joining method of claim 1 , wherein:

in the placement process, an abutting body is arranged so as to abut the at least one member undergoing elastic deformation; and

the member joining method further comprises a separation process of separating the abutting body from the joined first member and second member after the pressure maintaining process.

3. The member joining method of claim 2 , wherein:

in the filling process, the molten resin is filled into the gap and into a cavity provided in the abutting body; and

in the separation process, the abutting body is separated from a resin component that is continuously formed along a join section between the first member and the second member and that has a shape corresponding to the cavity.

4. The member joining method of claim 2 , wherein:

in the placement process, an outer abutting body configuring the abutting body is arranged at an outer peripheral side of the tubular portion; and

in the filling process, a diameter of the tubular portion is enlarged so as to abut an inner peripheral portion of the outer abutting body.

5. The member joining method of claim 4 , wherein the tubular portion is divided into segments around a circumferential direction thereof by a plurality of notches that extend along an axial direction of the tubular portion.

6. The member joining method of claim 4 , wherein:

the first member includes one or more communication paths that place an outer peripheral portion side and an inner peripheral portion side of the tubular portion in communication with each other, and that are connected to the gap; and

in the filling process, the resin is filled such that the resin reaches the one or more communication paths.

7. The member joining method of claim 6 , further comprising:

a process of forming a groove section configured from a plurality of grooves on an outer peripheral portion of the first member at a periphery of the one or more communication paths, wherein:

in the placement process, the first member is abutted by the abutting body such that the one or more communication paths and the groove section are covered, and

in the filling process, the resin is filled so as to pass through the one or more communication paths to reach the groove section.

8. The member joining method of claim 4 , wherein:

in the placement process, the second member and the outer abutting body are arranged so as to form a space between the outer abutting body and the second member, a portion of the space that is adjacent to the gap and into which the resin is injected having a greater width than the gap; and

in the filling process, the resin passes through the space before filling into the gap.

9. The member joining method of claim 2 , wherein:

the second member includes a tube-shaped shaft portion;

in the placement process, an inner abutting body configuring the abutting body is arranged at an inner peripheral side of the shaft portion; and

in the filling process, a diameter of the shaft portion is decreased so as to abut an outer peripheral portion of the inner abutting body.

10. The member joining method of claim 4 , wherein:

the second member includes a tube-shaped shaft portion;

in the placement process, an inner abutting body configuring the abutting body is arranged at an inner peripheral side of the shaft portion; and

in the filling process, a diameter of the shaft portion is decreased so as to abut an outer peripheral portion of the inner abutting body.

11. The member joining method of claim 1 , further comprising:

a surface treatment process that is performed prior to the placement process and in which a roughened portion is formed at a part of a surface of the first member and a part of a surface of the second member,

wherein, in the placement process, the gap is arranged at a portion where the roughened portion of the first member and the roughened portion of the second member face each other.

12. The member joining method of claim 1 , wherein the first member includes a reduced diameter portion defining an insertion portion formed along an inner surface of the first member between the main body and the tubular portion of the first member.

13. The member joining method of claim 12 , wherein the insertion portion abuts against the second member when inserted into the first member to seal an end of the gap.