US 3,938,112 AGranted

Tubular wheel speed sensor

AssigneeEaton Corporation

InventorThomas A. Gee

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Abstract

A rotation indication system having an improved sensing device for determining the velocity of a rotating body is disclosed. The improved sensing device is tubular in configuration and includes a source of magnetic flux and two pole pieces that define a split magnetic field. The sensing device is mounted in close proximity to a rotor which is connected to the rotating body. The rotor has apertures which interrupt the split magnetic field producing an output signal with a frequency proportional to the velocity of the rotating body. The sensing device is oriented relative to the rotor apertures so that each pole piece is alternatively in register with an aperture to produce the desired output signal. Since the sensing device is tubular in shape, it can be rotated about its axis to obtain the desired orientation with the rotor apertures, thus permitting the use of the sensing device with a wide range of rotor diameters having various aperture spacings.

Claims10

Dependent claims

A rotation indication system for generating signals in response to the rotation of a body, said indication system comprising:

a rotor affixed to and rotatable with said body, said rotor having at least one array of apertures on the outer periphery thereof;
sensing means mounted proximate to said rotor and cooperating with said rotor to establish an air gap, said sensing means being retained in a tubular housing permitting proper orientation of said sensing means for use with various sizes of said rotor or various spacings of said apertures in said rotor;
means for mounting said sensing means, said mounting means permitting said tubular housing and said sensing means retained thereby to move axially relative to said rotor while preventing angular movement of said tubular housing, said tubular housing being parallel to the axis of said body and spaced a predetermined distance from said axis;
gauging means adjacent said sensing means, said gauging means projecting from said sensing means and being in contact with said rotor for limiting axial movement of said sensing means;
said sensing means comprising a source of magnetic flux, means for producing a split magnetic flux path, and coil means, said split magnetic flux path being interrupted by said apertures when said rotor is rotated producing a flux change, said flux change inducing an output signal in said coil means, said coil means being minimally responsive to any flux change caused by relative axial movement between said sensing means and said rotor.

2 more elements

A signal generator providing a signal representative of the angular velocity of a rotating body, said signal generator comprising a rotor connected to and rotatable with said body, said rotor being of ferromagnetic material and having at least one array of apertures on the outer periphery thereof, sensing means mounted proximate to said rotor establishing an air gap therebetween, said sensing means including a magnetic flux source, means for producing a split magnetic flux path, and coil means, said split magnetic flux path producing means including first and second pole pieces positioned relative to said magnetic flux source so as to be parallel to and equidistant from said magnetic flux source, said sensing means being retained by retaining means in a tubular housing permitting axial and angular movement of said tubular housing and said sensing means retained thereby when proper orientation of said sensing means is being established for different rotor sizes and/or aperture spacings, said tubular housing being parallel to the axis of said body and spaced a predetermined distance from said axis, said proper orientation of said sensing means occurring when said first and said second pole pieces are alternatively in register with said apertures in said rotor resulting in the interruption of said split magnetic flux path by said apertures when said rotor is rotated causing a flux change, said proper orientation of said sensing means being retained by means for mounting said sensing means permitting axial movement of said tubular housing and said sensing means retained thereby while preventing angular movement of said tubular housing after said proper orientation of said sensing means is established, said axial movement being limited by gauging means adjacent said rotor, said coil means being responsive to said flux change to produce an output signal, said coil means being minimally responsive to any flux change resulting from relative axial movement between said sensing means and said rotor.

Dependencies are inferred from the claim text.