| 摘要 |
PROBLEM TO BE SOLVED: To suppress leakage of oil through a part between an inner peripheral surface of a body and an outer peripheral surface of a plunger and on the other hand, to suitably discharge the air mixed in a high pressure chamber to the outside.SOLUTION: An outer peripheral surface of a plunger 20 is provided with: a first membrane 61 having oil repellency; and a second membrane 62 located on an upper side of the first membrane 61 and having the oil repellency by being separated from each other in an axial direction C of the plunger 20. In addition, an inner peripheral surface of a body 10 is provided with a third membrane 63 having the oil repellency. Then, the first membrane 61, the second membrane 62, and the third membrane 63 are provided so that the third membrane 63 faces the first membrane 61, an upper end of the third membrane 63 is located on a lower side of a lower end of the second membrane 62, on the other hand, when the plunger 20 sinks in the body 10, the third membrane 63 faces the second membrane 62, and a lower end of the third membrane 63 is located on an upper side of an upper end of the first membrane 61. |
