Abstract: An in-tank type fuel pump which can easily be installed and reduces the vibration caused by the fuel pump. The fuel pumped up by a pump part passes through a filter to have foreign matter contained therein removed. Then, the fuel flows from a fuel passage, through an opening part in a cap, into a recessed part and a second fuel passage. The fuel that has flowed into the second fuel passage lifts a check valve and flows into the recessed part. Then, the fuel flows through a third fuel passage to a discharge pipe, and then is guided to the outside of the fuel tank. A ball moves within a large-diameter passage according to the fuel pressure to regulate the fuel pressure required for fuel injection. When the fuel pumping is ceased, the fuel pressure falls to 0, and therefore the ball is forced to contact a valve seat by the spring force of a compression coil spring. Then, the head part of the check valve is forced to contact a valve seat to block the fuel passage.

Abstract: A joint structure has a fuel supply pump disposed within a fuel tank in a vertical posture, and a fuel outlet pipe projecting from the upper end surface of the fuel supply pump. A cylindrical retaining member is fitted around the fuel outlet pipe and an O ring is also fitted around the fuel outlet pipe in contact with the upper end surface of the cylindrical retaining member. The inner surface of the O ring is in close contact with the outer surface of the outlet pipe. A cylindrical joint member penetrates the upper wall of the fuel tank and an upper opening of the joint member is connected to one end of a fuel supply pipe leading to an engine. The fuel outlet pipe is pressed into a lower opening of the joint member. At this time, the outer peripheral surface of the O ring retained by the cylindrical retaining member in contact therewith, comes in close contact with an inner surface of the joint member.