PURPOSE: To permit the proper adjustment of lubricating oil supplying amount by a method wherein an adjusting rod is arranged so as to oppose to and abut against a piston slidingly in contact with the inside of a cylinder fitted into a support cylinder having an introducing port and an oil injecting port while the adjusting rod is adjustably screwed into the support cylinder.

CONSTITUTION: When lubricating oil is sucked into the cylinder 14 and the cylinder is moved to the right, the piston 15 is abutted against the adjusting rod 11, a volume in the cylinder 14 is contracted and the lubricating oil is ejected to the outside of the support cylinder 8 through the non-return valve 22 of the oil injecting port 13. When the cylinder 14 contacts with a retaining ring 10, the cylinder 14 is returned and blocked by the non-return valve 22, thereafter, continues to return under compressing a spring 17. When the suction port 18 and the introducing port 12 are communicated, the lubricating oil is induced into the cylinder 14 by the spring 17 and the piston 15. The minute adjustment of piston stroke may be effected by moving the screwed position of the adjusting rod 11 with the support cylinder 8 even during the operation of the cylinder 14 and the piston 15, therefore, thereby the proper adjustment of the suction and delivery amounts of the lubricaring oil may be effected even under the operation of the pump.