INTERNAL PUMP

PROBLEM TO BE SOLVED: To provide an internal pump capable of contributing to reliability improvement by dissolving a problem of an area where vibration characteristics become instable due to a rotation speed enhancing process of the internal pump.SOLUTION: The internal pump includes: an impeller 5 fixed to a pump shaft 4; an upper radial bearing 20 and a lower radial bearing 21 that are provided respectively on the upper part and the lower part of a wet motor 2 rotatingly driving the pump shaft 4 and support the impeller 5 in the radial direction; and thrust bearings 22 and 23 that axially support a thrust disk 10a fixed to the pump shaft 4 in the lower part of the wet motor 2. The thrust disk 10a is provided with a substantially conical part by thickening the inner peripheral side thereof and thinning the outer peripheral side to be defined as an inclined thrust disk 10a. The thrust bearings 22 an 23 are provided facing the thrust disk 10a, and the pump shaft 4 is supported in a non-contact manner by fluid pressure generated in a clearance between the thrust disk 10a and the bearings.