| 摘要 |
A motor (18), which drives a pair of front rollers (17) of a draft part (16), is controlled such that the rotation speed of the pair of front rollers is decreased from a reference speed (N0) to a decelerated speed (N1) and thereafter increased to the reference speed based on a designed thickness profile (DP) including a slub length (L). The yarn length (La) spun while the rotation speed of the pair of front rollers is increased from the decelerated speed to the reference speed is computed in advance. When the rotation speed of the pair of front rollers is decreased from the reference speed to the.decelerated speed, the motor is controlled such that the rotation speed of the pair of front rollers is increased at a point in time at which the yarn length spun from when the rotation speed of the pair of front rollers is started to be decreased reaches a value obtained by subtracting the yarn length computed in advance from the slub length of the designed thickness profile. Therefore, a special yarn that accurately conforms to the designed thickness profile is manufactured. |
