Apparatus and method for determining axial stability

An apparatus for determining axial stability of a wheel of a vehicle, comprising:

• detection means for measuring attitude and location of said wheel while said wheel is set in a first poistion, a second position displaced rotationally from said first position, and a third position displaced rotationally back to approximately said first position to respectively determine a first vector, a second vector, and a third vector, each said vector having a common predetermined relationship to said wheel;
• processing means for determining dynamic stability vectors, including a wheel runout vector and an axial stability vector of the wheel, based on said measured attitudes and positions of the wheel, said detection means being responsive to said processing means;
• storage means for storing predetermined dynamic stability tolerance data for the wheel;
• and
• display means for displaying graphical representations of said wheel runout vector and said axial stability vector relative to said tolerance data.

A method for determining an axial stability of a wheel of a motor vehicle, comprising the steps of:

• measuring attitude and location of a wheel with the wheel set in a first position to determine a first vector having a predetermined relation to said wheel;
• rolling said wheel a number of degrees to a second position and measuring attitude and location thereof to determine a second vector also having said predetermined relation to said wheel;
• determining at least one of first axial parameters based on the first and second vectors;
• rolling said wheel to a third position and measuring the attitude and location of said wheel to determine a third vector also having said predetermined relation to said wheel;
• determining at least one of second axial parameters based on said second and third vectors;
• and
• determining a rotational axis stability vector based on said first and second axial parameters.

An apparatus for determining axial stability of a wheel of a vehicle, comprising:

• detection means for measuring attitude and location of said wheel while said wheel is set in a first position, a second position displaced rotationally from said first position, and a third position displaced rotationally from said second position to determine, respectively, a first vector, a second vector, and a third vector, each said vector having a common predetermined relationship to said wheel;
• processing means coupled to said detection means and configured for determining an axial stability vector of the wheel;
• storage means for storing predetermined dynamic stability tolerance data for the wheel;
• and
• display means for displaying graphical representations of said axial stability vector relative to said tolerance data.

A method for determining axial stability of a wheel of a motor vehicle, comprising the steps of:

• measuring attitude and rotary position of a wheel with the wheel in a first location to obtain a first measurement;
• rolling the wheel to a second location and measuring wheel attitude and rotary position to obtain a second measurement;
• determining at least one of second axial parameters based on the first and second measurements;
• rolling the wheel to a third position and measuring wheel attitude and rotary position to obtain a third measurement;
• determining at least one of first axial parameters based on the second and third measurements;
• and
• determining rotational axis stability based on said first and second axial parameters.

An apparatus for determining axial stability of a wheel of a motor vehicle, comprising:

• a sensor for measuring attitudes and rotary positions of a wheel in first, second, and third locations, respectively, to obtain first, second and third measurements;
• a processor configured for determining an axial stability parameter based on said first, second, and third measurements and for providing axial stability display data;
• and
• a display for receiving said display data and providing a visual indication of said axial stability parameter.