To accurately join a body part and a cap part contracted in rupture-division by managing fastening force of a pair of bolts for joining the body part and the cap part.
This connecting rod manufacturing method respectively rotates the pair of bolts at a high speed (S1), and switches to a low speed when a fastening quantity of the pair of bolts exceeds 4,400 degrees by a turning angle method (S2). In this case, when fastening torque of the bolts fastened by rotating at a low speed reaches 2 Nm being temporary fastening torque determined from experiment data when a worker respectively fastens the pair of bolts by fingers in manual work, rotation of the respective bolts is stopped and put in a standby state (S3), and the pair of bolts are respectively synchronized with a state of becoming 2 Nm as a starting point, and are fastened until the torque reaches 30 Nm (S4).
OKUMURA HIDEKI
Toshiyuki Miyadera
Tatsuhiko Sato