Vertical motor pump

Claim 1

A vertical motor pump comprising: a rotor fitted to a vertical rotary shaft; a stator secured to a casing, said stator being located in predetermined spaced juxtaposed relation to said rotor; an upper bearing and a lower bearing on respective sides of said rotor for rotatably journaling said rotary shaft at an upper portion and a lower portion respectively of said rotor; an impeller secured to said rotary shaft in a position below said lower bearing, said impeller being operative to perform a pumping action as it rotates with the rotary shaft as a unit to discharge a liquid upwardly; and a load reducing system interposed between said impeller and said lower bearing, said load reducing system being operative to reduce a pump thrust generated when the motor pump is operated; wherein one of said upper bearing and said lower bearing is constituted by a ball bearing, and a slide bearing is mounted on an outer periphery of a bearing case containing said ball bearing to allow said ball bearing to follow up the rotary shaft in vertical movement, and said rotary shaft is journaled, besides being journaled by said ball bearing, by a hydrostatic lubricated bearing system for bearing a radial load during operation.