Linear actuator for a variable-geometry member of a turbocharger, and a turbocharger incorporating same

摘要

A linear actuator for a variable-geometry member of a turbocharger includes a piston/rod assembly that can axially translate and also pivot to a limited extent. A permanent magnet is mounted in a fixed position within the actuator. A non-magnetized flux carrier is mounted in the piston/rod assembly, and its movement alters the magnetic field of the magnet. A Halls effects sensor detects the magnetic field and the signals produced by the sensor are used for determining axial position of the piston/rod assembly.

主权项

1. A vacuum-operated linear actuator for a variable-geometry member of a turbocharger, comprising:
an enclosure having a first end wall and an opposite second end wall spaced apart along an axial direction, and a flexible diaphragm within the enclosure, the enclosure and diaphragm cooperating to define an interior chamber for supporting a fluid pressure differential across the diaphragm; a piston that is metallic and has a cup-shaped configuration having a bottom wall connected to the diaphragm and a side wall extending from the bottom wall toward the first end wall of the enclosure; a spring engaged between the first end wall of the enclosure and the piston for biasing the piston and the diaphragm in a direction opposite the fluid pressure differential across the diaphragm; an actuator rod connected to the piston and the diaphragm and extending axially and penetrating through the second wall of the enclosure; a sensor assembly comprising a permanent magnet and a sensor each fixedly mounted with respect to the enclosure and proximate the first end wall of the enclosure, and a non-magnetized metallic flux modifier mounted on the piston, the flux modifier extending axially between a proximal end proximate the first end wall to a distal end proximate the piston, movement of the diaphragm and piston resulting in movement of the flux modifier, said movement of the flux modifier causing an alteration of the magnetic field of the magnet, said alteration of the magnetic field being sensed by the sensor, which produces an output signal indicative of the magnetic field; a slide-pivot bearing mounted at the first end wall of the enclosure and receiving the flux modifier, the slide-pivot bearing permitting the flux modifier to move axially and to pivot relative to the enclosure; and an articulated joint connecting the flux modifier to the bottom wall of the piston, the articulated joint permitting pivotal movement of the flux modifier relative to the piston.