| 摘要 |
PROBLEM TO BE SOLVED: To attract a magnet and a drive magnet to each other and to maintain rotation of a motor even when a magnet holder is moved to the impeller part side even when a magnet holder is moved to the impeller part side. SOLUTION: This pump comprises a partition wall 3 to partition a pump chamber 24 in which a magnet 13 is attached and an impeller part 1 to supply liquid is rotatably disposed; an annular drive magnet 4 having a given gapδbetween the partition wall 3 and the drive magnet and positioned facing the magnet 13 and rotationally driving the magnet 13 in a given direction; a magnet holder 5 formed in the shape of a cylinder with a bottom and holding the drive magnet 4 in the cylinder; and a back plate 6 formed of a magnetic material and arranged between the bottom of the magnet holder 5 and the drive magnet 4. In this case, the magnet holder 5 is formed such that a protrusion 55d to provide a gap, narrower than the gapδ, between the partition wall 3 and the protrusion is protruded from the central part of a bottom.
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