Torque sensor

Claim 2

A torque sensor comprising: a first rotor capable of being suitably driven for rotation; first sensing means provided on said first rotor, for detecting the rotation thereof; a second rotor provided in the neighborhood of said first rotor and rotatable with respect thereto; a torsion bar mechanically coupling said first and second rotors; second sensing means provided on said second rotor and disposed orthogonally to said first sensing means to couple with said first sensing means electromagnetically and to generate an electric signal according to the degree of the electromagnetic coupling between said two rotors variable with relative rotation of said rotors caused via said torsion bar; and an electric processing circuit for receiving the signal from said second sensing means and generating a signal corresponding to the magnitude of the twist of said torsion bar according to the received signal.

Claim 3

A torque sensor comprising: a first rotor having a first coil; a second rotor having a second coil disposed orthogonal to said first coil at a predetermined distance therefrom, said second rotor being electrically coupled to said first rotor by inductance coupling and mechanically coupled to said first rotor by a torsion spring; and an electric processing circuit for generating a signal corresponding to the magnitude of the twist of said torsion spring in response to a voltage signal generated across said second coil according to the magnitude of magnetic flux produced by said first coil and crossed by said second coil with relative rotation of both said rotors via said torsion spring.

Claim 4

A torque sensor comprising: a first rotor having a first coil; a second rotor having a second coil disposed orthogonal to said first coil at a predetermined distance therefrom, said second rotor being electrically coupled to said first rotor by inductance coupling and mechanically coupled to said first rotor by a torsion spring; and an electric processing circuit for generating a signal corresponding to the magnitude of the twist of said torsion spring in response to a voltage signal generated across said second coil according to the magnitude of magnetic flux produced by said first coil and crossed by said second coil with relative rotation of both said rotors via said torsion spring.

Claim 5

The torque sensor according to claim 2, which further comprises means for mounting said first and second coils such that the direction of the magnetic flux set up by said second coil is inversed to invert the phase of a voltage signal generated across said second coil with a leftward or rightward displacement of said second coil from a position corresponding to the center of said first coil.

Claim 6

The torque sensor according to claim 3, wherein said electric processing circuit includes; an oscillating circuit oscillating at a constant frequency to impress a pulse voltage signal upon said first coil; an amplifying circuit for amplifying a signal generated in said second coil; a left/right discriminating circuit for discriminating the direction if twist of said torsion spring by phase comparing signals from said amplifying circuit and from said oscillating circuit; and a peak hold circuit for detecting the peak of the output voltage of said amplifying circuit and generating a direct current voltage corresponding to the magnitude of twist of said torsion spring.

Claim 7

The torque sensor according to claim 4, wherein said electric processing circuit includes; a triangular wave generating circuit for generating a triangular wave at a constant frequency from the signal from said oscillating circuit; a pulse duration detecting circuit for generating a signal having a pulse duration proportional to a direct current voltage corresponding to the magnitude of twist of said torsion spring from signals from said triangular wave generator and from said peak hold circuit; and a current converting circuit for generating a current signal, said current signal having one of three current levels corresponding to signals from said left/right discriminating circuit respectively representing leftward twist, no twist and rightward twist of said torsion spring, said current signal having a duration corresponding to a signal from said pulse duration detecting circuit representing the magnitude of twist of said torsion spring; the output signal of said torque sensor being superimposed upon a power source line.

Claim 8

The torque sensor according to claim 5, which further comprises; means for connecting a power source and ground through brushes to slip rings; and means for permitting free rotation of said first and second rotors with respect to said housing.

Claim 9

In a power assisted steering apparatus having torque assisting motor means coupled to a steering main shaft, the torque sensor according to claim 2, which further comprises; means for causing the rotation of one of said first and second rotors according to torque generated in said main shaft; and means for driving said motor according to the output signal of said electric processing circuit.