Reamer with adjustable expansion/contraction, and bore finishing machine comprising the same

摘要

A reamer with adjustable expansion/contraction and a bore finishing machine comprising the reamer. The reamer has a rotation shaft that is externally operable and a grinding section. The grinding section is cylindrically shaped, and has a plurality of axially-extending slits in its peripheral wall and a tapered inner surface. The rotation shaft is connected via threaded sections to a sliding shaft, which is in turn connected to a diameter expansion member consisting of a tapered cone fitted into the tapered inner surface of the grinding section. When the rotation shaft is operated to rotate, the rotational motion is converted into linear motion of the slide shaft due to a guide pin and a guide hole. The linear motion moves the diameter expansion member back and forth inside the grinding section, thereby contracting/expanding the outer diameter of the grinding section mechanically and precisely. The bore finishing machine has a hollow main rotation spindle, and a rotation spindle inside the same. The main rotation spindle holds and rotates the reamer for grinding. The rotation spindle rotates the rotation shaft of the reamer to adjust the outer diameter of the grinding section mechanically and precisely. The bore finishing machine is also provided with a vibration applicator for application of axial vibration to the main rotation spindle, so that the reamer is axially stroked in grinding, resulting in further improved grinding accuracy.