| 摘要 |
The invention relates to a method of manufacturing a crankshaft 10 which comprises casting in place a hollow steel tube 18 into the crankshaft 10 and laser piercing bores 32 in at least the crank pins of the crankshaft to connect with the interior of the steel tube 18. Laser piercing avoids the risk of blockage of the oil duct by the burrs which would result from conventional drilling. 2214L |
