| 摘要 |
An annular groove is formed at an open end of a motor case, and a sliding contact projection, which is in an annular plate-shape and corresponding to the annular groove, is formed on a cover. A bottom of the annular groove and the sliding contact projection rotate relative to each other while being in sliding contact with each other to form an annular friction bonded portion therebetween. Wall portions of the annular groove are arranged at such positions as to be concentric with the friction bonded portion. Thus, a storage portion that stores burrs produced at the friction bonded portion is formed. A plurality of protrusions that protrude radially outward is formed on the sliding contact projection over all around. The storage portion is partitioned in the circumferential direction by using the protrusions as partitioning elements.
|
