Link mechanism, and variable turbine vane driving unit having the same

1. A link mechanism configured to rotate a second member around an axis of the second member in connection with movement of a first member, the link mechanism comprising:

a rotary shaft formed in a cylindrical shape around the axis and having a distal end fixed to the second member and a pin pushing thread hole recessed from a proximal end of the rotary shaft to the distal end in a direction parallel to the axis;

a link member having a shaft insertion hole which passes in a direction parallel to the axis and through which the proximal end of the rotary shaft can be inserted;

a detent pin configured to restrict the link member to be relatively non-rotatable around the axis with respect to the proximal end of the rotary shaft;

a pin support member to which the detent pin is fixed; and

a pushing bolt having a male thread section that can be thread-engaged with the pin pushing thread hole of the rotary shaft,

wherein a pin hole, which is formed from the proximal end of the rotary shaft to the link member, which is recessed toward the distal end in a direction parallel to the axis, and into which the detent pin can be fitted, is formed at the proximal end of the rotary shaft and the link member into which the proximal end is inserted,

a pin removing thread hole passing in a direction in which the detent pin fixed to the pin support member extends, and concentric with the pin pushing thread hole of the rotary shaft when the detent pin is fitted into the pin hole, is formed in the pin support member, and

a thread major diameter of the pin removing thread hole is larger than a thread major diameter of the male thread section of the pushing bolt, and smaller than an outer diameter of a bolt head section of the pushing bolt.

2. The link mechanism according to claim 1 , further comprising a removing bolt having a male thread section that can be thread-engaged with the pin removing thread hole.

3. The link mechanism according to claim 1 , further comprising a plurality of the detent pins,

wherein the plurality of the detent pins is fixed to the pin support member on a circumference around an axis of the pin removing thread hole in a circumferential direction at regular intervals.

4. The link mechanism according to claim 1 , wherein the axis of the pin pushing thread hole is disposed over the axis of the rotary shaft.

5. The link mechanism according to claim 1 , wherein a pin attachment hole passing in a penetration direction of the pin removing thread hole is formed in the pin support member, and

the detent pin has a male thread section formed at one end side of the detent pin, a fitting section formed at the other end of the detent pin and fitted into the pin hole, and a collar section formed at a boundary between the male thread section and the fitting section and projecting in a direction perpendicular to an axis of the detent pin.

6. A variable vane drive device of an axial-flow fluid machine including a rotor having a plurality of blades, a casing configured to rotatably cover the rotor, and a plurality of variable vanes disposed around the rotor in the casing in an annular shape, the variable vane drive device comprising:

an annular-shaped movable ring disposed at an outer circumferential side of the casing;

a plurality of ring support mechanisms disposed in a circumferential direction of the movable ring at intervals and configured to rotatably support the movable ring around the rotor;

a rotary drive mechanism configured to rotate the movable ring around the rotor; and

a link mechanism according to any one of claims 1 to 5 ,

wherein the link mechanism is configured to connect the movable ring to the variable vane such that a direction of the variable vane, which is the second member, is varied according to rotation of the movable ring, which is the first member.