Frictionless bearing chassis dynamometer

A frictionless bearing chassis dynamometer apparatus comprising:

• roll means for engaging at least one wheel of a vehicle during rotational movement of said wheel;
• means for sensing the speed of said roll means and generating a speed signal in accordance with the sensed speed of said roll means;
• power exchange means including an input shaft coupled to said roll means for simulating varying loads;
• first bearing means coupled to said input shaft or supporting said input shaft and said roll means and enabling rotational movement of said input shaft relative to a frame portion of said dynamometer;
• second bearing means disposed between said first bearing means and said frame portion of said dynamometer for supporting said first bearing means;
• inner/outer race means disposed in between said first and second bearing means and responsive to said speed signals for driving said first bearing means in the same direction as said input shaft and at a speed close to the speed of said input shaft to thereby cancel friction forces of said first bearing means which oppose rotational movement of said roll means.

A frictionless bearing, chassis dynamometer apparatus comprising:

• first and second roller means aligned along a common longitudinal axis for engaging a pair of wheels of a vehicle during rotational movement of said pair of wheels;
• encoder means for sensing the speed of sad first and second roll means and generating a speed signal in accordance with the speed of said first and second roll means;
• power exchange means disposed centrally in between said first and second roll means and including an input shaft coupled to and aligned with the axis of rotation of each of said first and second roll means for simulating variable loads to be driven by said pair of wheels of said vehicle;
• a pair of inner annular bearings each disposed on said input shaft at opposite ends of said input shaft;
• a pair of outer annular bearings, each one of said outer annular bearings being disposed coaxially in between an associated one of said inner annular bearings and an associated frame portion of said apparatus;
• a pair of inner/outer race members, each said inner/outer race member being disposed in between a respective one of said inner and outer annular bearings and each acting as an outer race for its respective inner annular bearing and an inner race for its respective outer annular bearing;
• and
• motor drive means responsive to said speed signal and coupled to said inner/outer race members for driving said inner/outer race members in the same direction of rotation as said first and second roll means and at variable speeds in accordance with the rotational speed of said first and second roll means, to thereby cancel frictional forces generated by said inner annular bearings which oppose rotational movement of said first and second roll means.

A frictionless bearing, chassis dynamometer apparatus comprising:

• a first roll for engaging one wheel of a vehicle during rotational movement of said wheel and adapted to rotate about a central longitudinal axis;
• a second roll spaced laterally apart from said first roll for engaging a second wheel of said vehicle during rotational movement of said second wheel and adapted to rotate about a central longitudinal axis, said central longitudinal axes of rotation of said first and second rolls further being longitudinally aligned such that said first and second rolls have a common longitudinal axis of rotation;
• a power exchange unit disposed in between said first and second rolls and having an input drive shaft having first and second ends in longitudinal alignment with the axes of rotation of said first and second rolls, said power exchange unit being operable to simulate variable loads;
• an electro-optical encoder for sensing the rotational speed of said first and second rolls and generating a variable electrical speed signal in accordance with the changing rotational speed of said first and second rolls;
• a first inner annular roller bearing circumscribing said first end of said input shaft and being in contact with said input shaft;
• a first annular outer roller bearing disposed concentrically over said first inner annular roller bearing and being supported by a first frame portion of said apparatus;
• said second end of said input shaft having a second inner annular roller bearing disposed concentrically thereover;
• a second outer annular roller bearing disposed concentrically over said second end of said input shaft in lateral alignment with said second inner annular roller bearing, said second outer annular bearing of said second end of said input shaft being supported by a second frame portion of said apparatus;
• a first inner/outer race member disposed concentrically between said first inner and first outer roller bearings at said first end of said input shaft forming an outer race for said first inner roller bearing and an inner race for said first outer roller bearing;
• a second inner/outer race member disposed concentrically between said second inner and second outer annular roller bearings at said second end of said input shaft;
• a first drive motor responsive to said variable electrical speed signal generated by said encoder means and coupled to said first inner/outer race member for driving said first inner/outer race member at a variable rotational speed alternately faster and slower than the rotational speed of said input shaft.
• a second drive motor responsive to said variable electrical speed signal generated by said encoder means and coupled to said second inner/outer race member for driving said second inner/outer race member at a variable rotational speed alternately faster and slower than the rotational speed of said input shaft.

A method for cancelling frictional forces in a chassis dynamometer which oppose rotational movement of a pair of rolls of the dynamometer as the rolls are driven by a pair of wheels of a vehicle under test, said method comprising:

• providing a power exchange device having an input shaft fixedly coupled to at least one of the rolls;
• providing an inner annular roller bearing coaxially disposed over said input shaft;
• providing an outer annular roller bearing coaxially disposed and laterally aligned with said inner annular roller bearing on said input shaft, said outer annular roller bearing being supported by a frame portion of the dynamometer;
• providing an inner/outer race member interposed between said inner and outer annular roller bearings and forming an outer race of said inner annular bearing and an inner race of said outer annular bearing;
• and
• driving said inner/outer race member at a variable rotational speed in relation to the rotational speed of said input shaft.