Variable geometry turbine device

A variable geometry turbine device, comprising:

• a turbine casing (5), wherein the turbine casing (5) is provided with an inlet duct (501), and defines an exhaust port (507) and a bypass chamber (503) therein;
• the exhaust port (507) and the bypass chamber (503) are disposed in parallel, and both are in communication with the inlet duct (501);
• a first annular chamber (2) and a second annular chamber (3) are in communication with each other and defined between the exhaust port (507) and the bypass chamber (503);
• a first radial channel (203) and a second radial channel (301) are formed just below the bypass chamber (503) and arranged along an axial direction of the bypass chamber (503), the first radial channel (203) is in communication with the first annular chamber (2), the second radial channel (301) is in communication with the second annular chamber (3), and a wall surface of the second annular chamber (3) internally communicated with the exhaust port (507) defines an air-bleed hole (302);
• a gear rotating sleeve (6), disposed inside the bypass chamber (503), wherein an end of the gear rotating sleeve (6) defines an opening in communication with the inlet duct (501), and another end of the gear rotating sleeve (6) is closed;
• a side of the gear rotating sleeve (6) defines a first notch (601) configured to be selectively connected and disconnected to the first radial channel (203), and a second notch (602) configured to be selectively connected and disconnected to the second radial channel (301);
• and opening and closing of the first radial channel (203) and the second radial channel (301) have a time difference;
• a rack actuator (4), connected to the another end being closed of the gear rotating sleeve (6) and configured to drive the gear rotating sleeve (6) to rotate circumferentially;
• and
• combined nozzle guide vanes (17), comprising:
• a fixed nozzle (7) fixedly disposed on a first nozzle wall surface (508) of the turbine casing (5), and an elastic nozzle mechanism (9), wherein the elastic nozzle mechanism (9) is configured to move reciprocally along an axial direction of the exhaust port (507) under a cooperative action of a pressure difference and an elastic force, leaf-shaped notches (204) are defined between the elastic nozzle mechanism (9) and the fixed nozzle (7), and a position of each of the leaf-shaped notches (204) along the radial direction of the exhaust port (507) is lower than a throat position (18) of the combined nozzle guide vanes (17).