Wheel speed sensor for an adaptive braking system

Abstract

The tone wheel is a heavy walled steel stamping having a flanged central opening adapted for pressing on to a pilot turned on the outside surface of the wheel hub, and a cylindrical flange contiguous to the usual offset portion of the brake disc and having teeth formed on its inside surface. The spaces between the teeth are filled with adhesive nonmagnetic material so that the tooth tips and the nonmagnetic material provide a smooth unbroken cylindrical surface. A radial adjustment for establishing a predetermined clearance between a pickup and the tone wheel is provided by a generally rectangular projection on the back of the pickup which fits into an elongated slot in the pickup bracket. The output of the pickup is used to control the adaptive braking system.

We claim:  .[.1. A wheel speed sensor comprising: 
     
        pilot of said wheel hub and rotatable therewith..]. 2. A wheel speed sensor comprising: a spindle;   a wheel hub rotatably mounted on said spindle;   .[.disc.]. brake means connected to said wheel hub and being rotatable therewith;   pickup means nonrotatably mounted on said spindle; and   a tone wheel connected to said hub and rotatable therewith, said tone wheel .[.having notches on an accessible surface;.]. .Iadd.having a portion extending radially with respect to said hub and terminating in an axially extending flange, said flange having axially extending notches; .Iaddend.   said pickup means being located in close proximity with said notches .[.movable relative thereto.]..Iadd., said notches being movable relative to said pickup means .Iaddend.to generate a signal representative of the rotational velocity of said tone wheel, .Iadd.said pickup means being movable radially with respect to said hub toward and away from the notches on the flange .Iaddend.and further comprising .[.projections on.]. .Iadd.means projecting from .Iaddend.said pickup means to locate said pickup means a predetermined distance from said tone wheel and to protect   
     
     
        said pickup means from damage due to normal vibrations. 3. The wheel speed sensor, as recited in claim 2, wherein said .[.projections.]. .Iadd.projecting means .Iaddend.are located on opposite sides of said 
     
     
        pickup means to accurately set said predetermined distance. 4. The wheel sensor, as recited in claim 2, wherein said .[.projections is.]. .Iadd.projecting means are .Iaddend.an extension substantially surrounding the portion of said pickup means in close proximity with said notches, said extension slidably engaging said tone wheel to protect said pickup means and accurately set said predetermined distance.