US 8,944,785 B2Granted

Piston and cylinder combination driven by linear motor with cylinder position recognition system and linear motor compressor, and an inductive sensor

AssigneeWhirlpool Corporation

InventorsDietmar Erich Bernhard Lilie, Paulo Sergio Dainez, Nerian Fernando Ferreira, Marcelo Knies

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Abstract

A piston and cylinder combination driven by linear motor with cylinder position recognition system, including a support structure forming an air gap; a motor winding generating a variable magnetic flow along part of the air gap; a cylinder having a head at one end; a piston connected to a magnet, the magnet driven by the magnetic flow of the motor winding to move inside a displacement path including at least partially the air gap; the displacement of the magnet making the piston reciprocatingly move inside the cylinder; and an inductive sensor disposed at a point of the displacement path of the magnet, such that when the piston reaches a position of closest approach to the cylinder head, the inductive sensor detects a variation in the magnetic field resulting from the corresponding position of the magnet, and generates a voltage signal arising from this magnetic field variation.

Claims18

Dependent claims

A piston and cylinder combination driven by a linear motor with cylinder position recognition system for providing a maximum operation capacity of the piston and cylinder combination, avoiding a collision of the piston with a cylinder head, said piston and cylinder combination comprising:

a support structure forming an air gap;
a motor winding generating a variable magnetic flow at least along part of the air gap;
a cylinder having a head at one of its ends;
a piston connected to a magnet, the magnet being driven by the magnetic flow of the motor winding to move along a displacement path including at least partially the air gap;
the displacement of the magnet making the piston reciprocatingly move inside the cylinder;
an inductive sensor comprising a sensor coil coupled directly to the motor winding adjacent to the displacement path of the magnet, the sensor coil comprising an oblong shape including an elongated dimension and a narrow dimension, wherein said elongated dimension is elongated relative to said narrow dimension, and wherein the elongated dimension extends transversely relative to the displacement path of the magnet and the narrow dimension extends axially along the displacement path of the magnet such that the sensor coil faces toward the air gap through which the magnet moves, and the magnet moves on the displacement path across the narrow dimension of the sensor coil, and such that when the piston reaches a pre-selected position in the displacement path, an edge of the magnet coincides with the position of the sensor, thereby inducing a variation in the magnetic field detected by the inductive sensor resulting from the corresponding position of the magnet, and the inductive sensor generates a voltage signal arising from this magnetic field variation.

3 more elements

A linear motor compressor having a piston and cylinder combination and a cylinder position recognition system for providing a maximum operation capacity of the piston and cylinder combination, avoiding a collision of the piston with a cylinder head and a valve board,

the linear motor compressor comprising:
a support structure forming an air gap;
a motor winding generating a variable magnetic flow at least along part of the air gap;
a cylinder having a head and a valve board at its upper end, which admits low pressure air into the cylinder, from a low pressure air chamber, and discharges high pressure air out of the cylinder;
a piston connected to a magnet, the magnet being driven by the magnetic flow of the motor winding to move inside along a displacement path including at least partially the air gap;
the displacement of the magnet making the piston reciprocatingly move inside the cylinder;
an inductive sensor comprising a sensor coil coupled directly to the motor winding adjacent to the displacement path of the magnet, the sensor coil comprising an oblong shape including an elongated dimension and a narrow dimension, wherein the elongated dimension is longer than the narrow dimension, and wherein the elongated dimension extends transversely relative to the displacement path of the magnet and the narrow dimension extends axially along the displacement path of the magnet such that the sensor coil faces toward the air gap, in which the magnet moves, and the magnet moves on the displacement path across the narrow dimension of the sensor coil, and such that when the piston reaches at least a pre-selected position, an edge of the magnet coincides with the position of the sensor, the inductive sensor detects a magnetic field variation resulting from the corresponding position of the magnet, and generates a voltage signal arising from this magnetic field variation.

4 more elements

Dependencies are inferred from the claim text.