| 摘要 |
PURPOSE: A boring tool of a cylinder block is provided to reduce the reject ratio of processing a material by preventing burning and shaking of a tool caused by a processing chip upon boring a hole on a journal portion of a crank shaft in the cylinder block. CONSTITUTION: A boring tool(100) processes boring holes settled as a journal portion of a crank shaft penetrates through in a cylinder block. The boring tool of the cylinder block is made up of a front end(2), a guide unit(4) integrally connected to the front end by a taper unit(3) and a rear end(6) integrally connected to the guide unit by another taper unit(5). Plural slide grooves(7) are made up lengthwise around the cylindrical circumference of the guide unit. Upon boring a hole in the cylinder block, processed chips are discharged to the rear end of a tool along with the slide grooves of the guide unit and then to the outside. Thereby, a processing reject ratio is decreased by preventing a burn-out phenomenon caused by the processed chip.
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