Slip controller for a continuously variable transmission

A method for controlling a continuously variable transmission having a drive end and a driven end and having operative means for providing a mechanical operative connection between said drive and driven ends and said operative means defining an actual slip (S.sub.act) between said ends, said ends having respective rotational axes and at least one of said ends including a rotating element displaceable along the rotational axis corresponding thereto, the method comprising the steps of:

• equipping said transmission with adjusting means for mechanically acting on said operative means to adjust said actual slip (S.sub.act) of said operative means relative to said drive and driven ends;
• providing detecting means for detecting the axial displacement of said element;
• configuring said detecting means as a single sensor adapted to also detect the rotation of said element and to output an output signal indicative of said rotation and said axial displacement;
• providing control means which includes means for providing a pregiven desired slip (S.sub.des);
• and,
• evaluating said output signal and controlling said actual slip (S.sub.act) to said pregiven desired slip (S.sub.des) in dependence upon said axial displacement and said rotation detected by said single sensor by acting on said adjusting means.

A method for controlling a continuously variable transmission having a drive end and a driven end and having a continuous band for providing a mechanical operative connection between said drive and driven ends and said continuous band defining an actual slip (S.sub.act) between said ends, the method comprising the steps of:

• configuring said ends to be respective pulleys and each one of said pulleys being defined by a pair of conical pulley discs;
• configuring one of said conical pulley discs of each pair to be axially displaceable relative to the other conical pulley disc of the same pair;
• providing said continuous band as a belt or chain connected between and mounted on said pulleys;
• equipping said transmission with adjusting means for acting on the axially displaceable pulley disc to adjust said actual slip (S.sub.act) between said continuous band and said pulleys;
• providing control means including first means for providing a pregiven desired slip (S.sub.des);
• adapting said control means to include second means for determining said actual slip (S.sub.act);
• adapting said control means to include a comparator for comparing said desired slip (S.sub.des) to said actual slip (S.sub.act) to obtain a comparator output;
• and,
• controlling said actual slip (S.sub.act) to said pregiven desired slip (S.sub.des) in dependence upon said comparator output.

An arrangement for controlling a continuously variable transmission having a drive end and a driven end, the arrangement comprising:

• operative means for providing a mechanical operative connection between said drive and driven ends and said operative means defining an actual slip (S.sub.act) between said ends;
• said ends having respective rotational axes and at least one of said ends including a rotating element displaceable along the rotational axis corresponding thereto;
• adjusting means for mechanically acting on said operative means to adjust said actual slip (S.sub.act) of said operative means relative to said drive and driven ends;
• detecting means for detecting the axial displacement of said element;
• said detecting means being configured as a single sensor adapted to also detect the rotation of said element and to output an output signal indicative of said rotation and said axial displacement;
• control means including means for providing a pregiven desired slip (S.sub.des);
• and,
• said control means further including means for evaluating said output signal and controlling said actual slip (S.sub.act) to said pregiven desired slip (S.sub.des) in dependence upon said axial displacement and said rotation detected by said single sensor by acting on said adjusting means.

An arrangement for controlling a continuously variable transmission having a drive end and a driven end, the arrangement comprising:

• operative means for providing a mechanical operative connection between said drive and driven ends and said operative means defining an actual slip (S.sub.act) between said ends;
• said ends having respective rotational axes and at least one of said ends including a rotating element displaceable along the rotational axis corresponding thereto;
• adjusting means for mechanically acting on said operative means to adjust said actual slip (S.sub.act) of said operative means relative to said drive and driven ends;
• said ends being respective pulleys and each one of said pulleys being defined by a pair of conical pulley discs;
• one of said conical pulley discs of each pair being axially displaceable relative to the other conical pulley disc of the same pair;
• said operative means being a band, belt or chain connected between and mounted on said pulleys;
• said adjusting means being adapted to act on the displaceable pulley discs to adjust said actual slip (S.sub.act) between said operative means and said pulleys;
• a first rpm detector for detecting the rpm of one of the pulley discs of a first one of said pulleys;
• a second rpm detector for detecting the rpm of one of the pulley discs of the second one of said pulleys;
• velocity detector for detecting the velocity (V.sub.B) of said operative means;
• and,
• control means for operating on said adjusting means to control said actual slip (S.sub.act) to a desired slip (S.sub.des) in dependence upon the detected rpms of said one pulley discs, respectively, and in dependence upon said velocity (V.sub.B) of said operative means.