WORKPIECE BORE SIZE MEASURING METHOD AND ITS INSTRUMENT

PROBLEM TO BE SOLVED: To provide a workpiece bore size measuring method and its instrument for rapidly, simply, and accurately measuring the bore size of a workpiece by a simple structure. SOLUTION: According to this workpiece bore size measuring method, the bore size of the workpiece is measured by supplying compressed air from an air supply means to an inner circumferential part of the cylindrical workpiece to detect its back pressure. First and second workpieces are severally connected to the supply means. The supply of compressed air to the first workpiece is shut off while compressed air is supplied to the second workpiece. With the supply of compressed air to the first workpiece is shut off, the supply of compressed air to the second workpiece is shut off. A prescribed time period after the supply of compressed air to the second work is shut off with the supply of compressed air to the second workpiece cut off, the supply of compressed air to the first workpiece is started. A prescribed time period after the supply of compressed air to the first workpiece is started, the back pressure of the compressed air is detected. The bore size of the first workpiece is acquired from the detection result. COPYRIGHT: (C)2005,JPO&NCIPI