| 摘要 |
PURPOSE:To form a port hole with high precision, by a method wherein a cylinder sleeve is blanked to form a port hole, and a chamfering, about equal to the thickness of a plate, is applied along a vent passage formed in a cylinder body. CONSTITUTION:A port hole P, formed with an intake air port 3a, a scavenging port 3b, and an exhaust port 3c, is formed in a cylinder sleeve 3 pressed in a cylinder body 1 of a cylinder 1, and is smoothly connected to a vent passage C formed with an intake air passage 2a, a scavenging passage 2b, and an exhaust passage 2c, being all formed in the cylinder body 2. In which case, since the port hole P is formed by blanking processing, a side P1 is extended parallel to a plane F including the axis of the cylinder, and the port hole, except the exhaust port 3c, is formed so as to have width narrower than that of the vent passage C. Since, in case this constitution is left as it is, a high projection E is present between the port hole P and the vent passage C, a tool, such as grinder, is inserted from the inner side to cut the projection E to chamfer it for smoothing. |
