Vane adjustment mechanism for variable capacity turbine, and assembling method for the same

A vane adjustment mechanism used in a variable-capacity turbine to control the quantity of exhaust gas, the vane adjustment mechanism comprising:

• a base unit having the shape of a short pipe, said base unit having a first flange on an outer surface and a second flange on an inner side with respect to the direction of exhaust gas flow,
• wherein said base unit comprises an inner base unit having said first and second flanges, and an outer base unit into which said inner base unit is inserted;
• a plurality of vanes, positioned along the circumference of said base unit, for adjusting the quantity of exhaust gas;
• a link plate having an inner circular edge that engages with an outer edge of said base unit in such a way that said link plate is free to rotate;
• a plurality of vane lever units connecting said plurality of vanes and said link plate, wherein said vane lever units run through vane shaft holes in said base unit;
• and
• a plurality of U-shaped indentations spaced at regular angular intervals on the inside surface of said inner base unit or said outer base unit from said first flange to said second flange, so that said U-shaped indentations form said vane shaft holes to accommodate said vane lever units when said inner base unit is inserted into said outer base unit to block said U-shaped indentations in such a way that said vane lever units are free to rotate,
• wherein the mid-portion of a vane shaft of each of said vane lever units has a narrow portion which has a smaller diameter than the ends of said vane shaft, which reduces the contacting surface area with said U-shaped indentation so as to prevent said vane shaft from seizing in said U-shaped indentation.