| 摘要 |
A cutter mounted on a boring head includes a shaft and a roller body rotatably mounted thereon The greasing of bearings disposed between the roller body and shaft is achieved through an axial bore formed in the shaft and into which a filling plug is inserted. Grease is pumped through the filling plug and into channels in which the bearings are disposed. The filling plug is then removed, leaving the bore essentially grease-free. To prevent the escape of grease from the passage during a cutting operation, while accommodating thermal expansion of the grease, a grease retainer plug is secured in the passage. The retainer plug forms a space which communicates with the bearings for receiving thermally expanding grease. If the volume of expanded grease exceeds the volume of that space, the grease passes through a pressure relief valve and displaces a cover of the valve to create another space of gradually expanding volume for receiving the grease. |
