| 摘要 |
PURPOSE:To prevent the damage of a diaphragm so as to prolong its life by forming such structure as to enable the removal of solid contaminant such as abrasion powder by an oil filter before oil in an oil operating chamber reaches an oil chamber in the latter part of an oil discharge stroke. CONSTITUTION:When a plunger reaches the bottom dead center during reciprocating motion, an oil discharge port 21 is totally closed, and a diaphragm 7 is pressed to a backup plate 8 by the pressure difference between an oil operating chamber 9 and a pump chamber 10. When the plunger 6 then enters its discharge stroke and starts its going motion to the right, pressure is applied to oil in the oil operating chamber 9, so that the oil is discharged to a discharge pipe 18, pushing a discharge valve 14 open. When the plunger reaches near the top dead center, the side face ring groove of a plunger oil passage 20 and the oil discharge port 21 start coinciding with each other, and the chamber 9 and an oil chamber 24 are placed in the communicated state in the latter part of the discharge stroke, so that the oil in the chamber 9 is discharged to the oil chamber 24 through an oil filter 28. |
