| 摘要 |
<p>The motor (1) drives a fan (3) circulating hot air in a chamber (2), for example a process heating oven. The fan (3) is carried on a shaft extension passing through the chamber wall (7). The motor shaft is of enlarged diameter and is hollow (4). At the driving end, and outboard of the bearing, are several outlet holes (9). An auxiliary fan mounted on the shaft between motor (2) and wall (7) draws air through the hollow shaft from an inlet at the non-drive end. The air passing through the shaft removes heat leaking from the hot air chamber along the shaft, cooling the drive end bearing (5). The shaft extension is of the smallest diameter practical, to limit the heat leakage. For the same reason it is also hollow.</p> |
