| 摘要 |
PROBLEM TO BE SOLVED: To provide a plunger fitted into a cylinder of a pneumatic dispenser discharging viscous material, preventing viscous material leakage while achieving air removal in a filling stage of the viscous material into the cylinder, and preventing compressed air leakage in a discharge stage from the pneumatic dispenser.SOLUTION: A plunger 10 includes a first portion 80 positioned forward and a second portion 82 positioned rearward. The second portion has a hollow structure, and includes a circumferential wall part 84. An inner circumferential surface 86 of the circumferential wall part has a taper surface. The circumferential wall part has a thickness size reduced as it becomes distant from the first portion in an axial direction. As a result, the circumferential wall part is reduced in bending rigidity as it becomes distant from the first portion in the axial direction, and is likely to be electrically deformed in a diameter direction. The first portion has a solid structure, functions as a rigid body relatively to the second portion, and includes a partition wall surface 89 separating internal space of the second portion from the solid part of the first portion. |
