| 摘要 |
In a conventional resistance welding-use electrode, a foot portion at the end is divided into three segments. An object such as a cap is inserted into a hole at the end. The foot portion is bent inward to hold the object by a force, and the object (cap) is pressed to a stem. Under this condition, a current is fed to perform resistance welding. A gap remains between the individual segments of the foot portion. Therefore, the current density is uneven, producing unevenness in the welding. A soft object may deform. The electrode wears and deforms due to repeated use, reducing its useful life. Because of the existence of the gap, pressing marks are sometimes formed in the welded portion. In the present invention, a permanent magnet is embedded at the end portion of the electrode to hold the object by magnetic force of the permanent magnet. Even when the foot portion at the end portion is closed, the inner diameter of the hole produced by the surrounding foot portion is designed to be larger than the outer diameter of the object, so that the pressing force is not applied to the object.
|
