| 摘要 |
PURPOSE:To improve mass-productivity and working precision by opening a scavenging port by means of machining cast cylinder for a two cycle engine wothout using complicated cores. CONSTITUTION:A scavenging port 4 is in closed state when it is cast. Accordingly, the core is of simple straight line shape, easy to manufacture and of good mold releasing property. A T type cutter 5 smaller than the inner diameter of a cylinder is inserted into the inner portion of the cast material cylinder, equipped at the position of the scavenging part to bore a part of an inner wall 2 and open a scavenging port 4 in the cylinder. The upper and lower edges of the scavenging port 4 can be formed by the simple T type cutter 5 in the cylinder wall portion in parallel and with high precision. |
