Power steering mechanism with magnetoelastic torsion bar

A steering mechanism for turning steerable wheels of a vehicle, said steering mechanism comprising:

• an input member rotatable about a first axis;
• an output member rotatable about a second axis coaxial with said first axis;
• a torsion bar connecting said input member and said output member, said torsion bar being fixedly connected to said output member and twisting upon relative rotation between said input member and said output member about said axes;
• said torsion bar being made of a magnetoelastic material and having a defined axially extending and circumferentially extending surface area which carries a magnetic field, which magnetic field varies upon twisting of said torsion bar;
• and
• at least one magnetic field detector located to sense variance in said magnetic field;
• said input member being interposed between said torsion bar and said at least one magnetic field detector and being made of a non-magnetic material;
• wherein said input member has means for limiting the amount of twisting of said torsion bar, said means including a connection with said output member which permits rotation of said input member relative to said output member for a limited amount and which thereafter connects said input member to said output member for joint rotation.