Method for the roller-straightening of crankshafts

A method for roll straightening a crankshaft during or after a deep rolling process using deep rolling tools, wherein a work roller is pressed into a recess on a side of a bearing journal of the crankshaft with a straightening force, the method comprising:

• determining an individual vector (44, 45, 46, 47) of a runout for each bearing journal (Hi, Pi) of the crankshaft (8, 8′);
• determining a resulting vector (25) from the individual vectors (34, 35, 36, 37, 38) according to a size value and a direction (26);
• and then
• applying a straightening force (46, 50) to each bearing journal (Hi, Pi) of the crankshaft (8, 8′);
• wherein a direction of the straightening force (46, 50) lies in the direction (26) of the resulting vector (25);
• wherein a size value of the straightening force (27, 30) continually changes as the crankshaft is rotated through 360 degrees around an axis of rotation;
• and
• wherein the size value of the straightening force (27, 30) varies between 0 and a multiple value of the size value of the resulting vector (25).

A method for roll straightening a crankshaft, the crankshaft comprising a plurality of bearings along a length of the crankshaft and a longitudinal axis, the method employing deep rolling tools comprising a support roller head including support rollers, a deep rolling head and work rollers, the method comprising:

• rotating the crankshaft about the longitudinal axis;
• measuring the size and direction of a runout on each of the plurality of bearings to determine a corresponding runout vector for each of the plurality of bearings;
• determining a size and direction of a resultant runout vector from a sum of each of the runout vectors for each of the plurality of bearings;
• for each of the plurality of bearings, applying at a first point located on a circumference of the bearing, a roll straightening force being directed toward the first longitudinal axis, the roll straightening force having a first size at least equal to the size of the resultant runout vector and having a direction matching the direction of the resultant runout vector;
• and
• for each of the plurality of bearings, continuously reducing the size of the roll straightening force applied to the bearing as the crankshaft rotates about the longitudinal axis such that, at a second point located on the circumference of the bearing that is 180 degrees from the first point, the roll straightening force applied to the bearing has a second size equal to one of zero and a fraction of the size of the resultant runout vector.