High resolution proximity detector employing magnetoresistive sensor disposed within a pressure resistant enclosure

Claim 2

A proximity sensor adapted for detecting the presence of a target within a sensing region, said sensor comprising: housing means including a generally tubular elongate probe portion defining a closed cavity therein; an annular permanent magnet coaxially disposed within said cavity at an end of said probe portion proximate said sensing region; means including at least one ferrous member disposed concentrically within said magnet and coacting therewith to establish a focused magnetic field within said region; magnetoresistive sensor means disposed within said magnet to detect distortion of said magnetic field effected by said target; and means in circuit with said sensor means operative to generate an output signal as a function of said sensed magnetic field distortion, said field focusing means comprising an elongated pin formed of ferrous material disposed coaxially within said magnet and selectively axially positionable with respect to said magnet and sensor means.

Claim 3

The proximity sensor of claim 1 wherein said field focusing means further comprises a tubular band formed of ferrous material disposed coaxially externally of said magnet.

Claim 4

The proximity sensor of wherein said permanent magnet is radially polarized.

Claim 5

The proximity sensor of wherein said permanent magnet is radially polarized.

Claim 6

The proximity sensor of claim 1, wherein said sensor means comprises first and second magnetoresistive elements having orthogonally disposed characteristic principle field sensing planes.

Claim 7

The proximity sensor of claim 4, wherein said principle field sensing planes are substantially parallel with the sensor axis of concentricity.

Claim 8

The proximity sensor of claim 5, wherein said first and second elements are disposed in a T configuration.

Claim 9

The proximity sensor of claim 5, wherein said first and second elements are disposed in an L configuration.

Claim 10

The proximity sensor of claim 1, wherein said sensor means comprises a magnetoresistive element having a characteristic principle field sensing plane disposed obliquely to the sensor axis of concentricity.

Claim 11

The proximity sensor of claim 1, further comprising structure disposed concentrically within said magnet defining at least one recess for insulatively receiving said sensor means, and a bore for receiving said field focusing means.

Claim 12

The proximity sensor of claim 1, wherein said means in circuit with said sensor means is insulatively carried within said probe portion.

Claim 13

A proximity sensor adapted for detecting target portions of a rotating machine element disposed within a pressurized fluid environment confined by a relatively fixed machine housing, said sensor comprising: housing means including a body portion extending externally of said machine housing for interface with a host machine circuit, and an elongate probe portion extending inwardly of said machine housing to a terminal radially outwardly adjacent the path of travel of said target portions, said probe portion defining a sealed cavity therein; an annular permanent magnet coaxially disposed within said cavity adjacent said terminus; means including at least one ferrous member disposed concentrically within said magnet and coacting therewith to establish a focused magnetic field within a sensing region external of said probe portion encompassing a limited segment of said target portion path of travel; magnetoresistive sensor means disposed within said magnet to detect distortion of said magnetic field effected by said target portions; and means in circuit with said sensor means operative to generate an output signal as a function of said sensed magnetic field distortion, said means including at least one ferrous member comprising an elongated pin disposed coaxially within said magnet and selectively axially positionable with respect to said magnet and sensor means.

Claim 14

A proximity sensor adapted for detecting target portions of a rotating machine element disposed within a pressurized fluid environment confined by a relatively fixed machine housing, said sensor comprising: housing means including a body portion extending externally of said machine housing for interface with a host machine circuit, and an elongate probe portion extending inwardly of said machine housing to a terminal radially outwardly adjacent the path of travel of said target portions, said probe portion defining a sealed cavity therein; an annular permanent magnet coaxially disposed within said cavity adjacent said terminus; means including at least one ferrous member disposed concentrically within said magnet and coacting therewith to establish a focused magnetic field within a sensing region external of said probe portion encompassing a limited segment of said target portion path of travel; magnetoresistive sensor means disposed within said magnet to detect distortion of said magnetic field effected by said target portions; and means in circuit with said sensor means operative to generate an output signal as a function of said sensed magnetic field distortion, said means including at least one ferrous member comprising an elongated pin disposed coaxially within said magnet and selectively axially positionable with respect to said magnet and sensor means.

Claim 15

The proximity sensor of claim 11, wherein said probe portion threadably engages said machine housing for selective axial positioning of said sensor with respect to said rotating target portions.

Claim 16

The proximity sensor of claim 12, wherein said housing body portion has a radial step formed therein coacting with the external surface of said housing to embrace an application specific tubular spacer having a predetermined axial dimension for establishing a sensor inward limit of travel.

Claim 17

The proximity sensor of claim 13, further comprising first seal means disposed intermediate said housing means and spacer and second seal means disposed intermediate said spacer and machine housing.

Claim 18

The proximity sensor of claim 13, further comprising seal means disposed intermediate said housing means and said machine housing.

Claim 19

The proximity sensor of claim 11, wherein said body portion and probe portion are integrally formed.

Claim 20

The proximity sensor of claim 11, wherein said probe portion is formed of non-ferrous material.

Claim 21

A proximity sensor adapted for detecting the presence of a target within a sensing region, said sensor comprising: housing means including a generally tubular elongate probe portion defining a closed cavity therein; an annular permanent magnet coaxially disposed within said cavity at an end of said probe portion proximate said sensing region; means including at least one ferrous member disposed concentrically within said magnet and coacting therewith to establish a focused magnetic field within said region; magnetoresistive sensor means disposed within said magnet to detect distortion of said magnetic field effected by said target; and means in circuit with said sensor means operative to generate an output signal as a function of said sensed magnetic field distortion, said field focusing means comprising an elongated pin formed of ferrous material disposed coaxially within said magnet and a tubular band formed of ferrous material disposed coaxially externally of said magnet.

Claim 22

A proximity sensor adapted for detecting the presence of a target within a sensing region, said sensor comprising: housing means including a generally tubular elongate probe portion defining a closed cavity therein; an annular permanent magnet coaxially disposed within said cavity at an end of said probe portion proximate said sensing region; means including at least one ferrous member disposed concentrically within said magnet and coacting therewith to establish a focused magnetic field within said region; magnetoresistive sensor means disposed within said magnet to detect distortion of said magnetic field effected by said target; and means in circuit with said sensor means operative to generate an output signal as a function of said sensed magnetic field distortion, said field focusing means comprising an elongated pin formed of ferrous material disposed coaxially within said magnet and a tubular band formed of ferrous material disposed coaxially externally of said magnet.

Claim 23

The proximity sensor of claim 18, wherein said permanent magnet is radially polarized.

Claim 24

The proximity sensor of claim 18, wherein said sensor means comprises first and second magnetoresistive elements having orthogonally disposed characteristic principle field sensing planes.

Claim 25

The proximity sensor of claim 20, wherein said principle field sensing planes are substantially parallel with the sensor axis of concentricity.

Claim 26

The proximity sensor of claim 21, wherein said first and second elements are disposed in a T configuration.

Claim 27

The proximity sensor of claim 21, wherein said first and second elements are disposed in an L configuration.

Claim 28

The proximity sensor of claim 18, wherein said sensor means comprises a magnetoresistive element having a characteristic principle field sensing plane disposed obliquely to the sensor axis of concentricity.

Claim 29

The proximity sensor of claim 18, further comprising structure disposed concentrically within said magnet defining at least one recess for insulatively receiving said sensor means, and a bore for receiving said field focusing means.

Claim 30

The proximity sensor of claim 18, wherein said means in circuit with said sensor means is insulatively carried within said probe portion.

Claim 31

A proximity sensor adapted for detecting target portions of a rotating machine element disposed within a pressurized fluid environment confined by a relatively fixed machine housing, said sensor comprising: housing means including a body portion extending externally of said machine housing for interface with a host machine circuit, and an elongate probe portion extending inwardly of said machine housing to a terminus radially outwardly adjacent the path of travel of said target portions, said probe portion defining a sealed cavity therein; an annular permanent magnet coaxially disposed within said cavity adjacent said terminus; means including at least one ferrous member disposed concentrically within said magnet and coacting therewith to establish a focused magnetic field within a sensing region external of said probe portion encompassing a limited segment of said target portion path of travel; magnetoresistive sensor means disposed within said magnet to detect distortion of said magnetic field effected by said target portions; and means in circuit with said sensor means operative to generate an output signal as a function of said sensed magnetic field distortion, said field focussing means comprising an elongated pin formed of ferrous material disposed coaxially within said magnet and a tubular band formed of ferrous material disposed coaxially externally of said magnet.

Claim 32

A proximity sensor adapted for detecting target portions of a rotating machine element disposed within a pressurized fluid environment confined by a relatively fixed machine housing, said sensor comprising: housing means including a body portion extending externally of said machine housing for interface with a host machine circuit, and an elongate probe portion extending inwardly of said machine housing to a terminus radially outwardly adjacent the path of travel of said target portions, said probe portion defining a sealed cavity therein; an annular permanent magnet coaxially disposed within said cavity adjacent said terminus; means including at least one ferrous member disposed concentrically within said magnet and coacting therewith to establish a focused magnetic field within a sensing region external of said probe portion encompassing a limited segment of said target portion path of travel; magnetoresistive sensor means disposed within said magnet to detect distortion of said magnetic field effected by said target portions; and means in circuit with said sensor means operative to generate an output signal as a function of said sensed magnetic field distortion, said field focussing means comprising an elongated pin formed of ferrous material disposed coaxially within said magnet and a tubular band formed of ferrous material disposed coaxially externally of said magnet.

Claim 33

The proximity sensor of claim 27, wherein said probe portion threadably engages said machine housing for selective axial positioning of said sensor with respect to said rotating target portions.

Claim 34

The proximity sensor of claim 28, wherein said housing body portion has a radial step formed therein coacting with the external surface of said housing to embrace an application specific tubular spacer having a predetermined axial dimension for establishing a sensor inward limit of travel.

Claim 35

The proximity sensor of claim 29, further comprising first seal means disposed intermediate said housing means and spacer and second seal means disposed intermediate said spacer and machine housing.

Claim 36

The proximity sensor of claim 29, further comprising seal means disposed intermediate said housing means and said machine housing.

Claim 37

The proximity sensor of claim 27, wherein said body portion and probe portion are integrally formed.

Claim 38

The proximity sensor of claim 27, wherein said probe portion is formed of non-ferrous material.