Abstract: A pump for low-viscosity fuel comprises a pump shaft 6 installed in a pump housing 2, 3, 4 and divided into a drive-side shaft 6A and a driven-side shaft 6B, a partition 12 provided between the drive-side shaft and the driven-side shaft of the pump shaft to prevent leakage of fuel from the housing, and a magnetic coupling 13 for transferring torque from the drive-side shaft to the driven-side shaft of the pump shaft through the partition, the magnetic coupling being disposed such that a first clearance C1, D1 between the magnetic coupling and the partition is larger than a second clearance C2, D2 between the magnetic coupling and the pump housing. When wobble occurs in the pump shaft owing to wear of the sliding contact portions thereof, the magnetic coupling makes contact with the pump housing before contacting the partition, thereby enabling the rotation of the pump shaft to be stopped before fuel leakage occurs.

Abstract: A radial piston pump for low-viscosity fuel according to a first aspect of the invention comprises a pump housing, which is constituted of as few as two structural bodies (from among a drive-side housing member 2A, a fixed cylinder 81 and a cover 4), and a leaf valve member 82 which is formed with intake valves 87 for opening and closing intake side passages 27 and discharge valves 88 for opening and closing discharge side passages 28 and is sandwiched between two structural bodies (fixed cylinder 81 and cover 4). The first aspect of the invention reduces the number of components constituting the pump housing, enables highly precise overall axial alignment, prevents wobbling of a pump shaft 9 of the pump, increases performance and reliability and reduces cost.