Abstract: A motor includes a stator and a rotor having a rotor shaft. The motor includes a bearing having an inner ring and an outer ring that are configured to rotate relative to each other. The inner ring is supported by the rotor shaft. The motor also includes a holder that supports the outer ring. The holder is clearance-fitted to a retainer on a stator side. A rotation prevention apparatus configured to prevent the rotation of the holder is positioned between the holder and a stopper member on the stator side.

Abstract: A centrifugal pump includes a motor portion including a rotor rotatably disposed in a rotor chamber and includes a pump portion including an impeller rotatably disposed in a pump chamber. The impeller is coupled to the rotor. The centrifugal pump also includes a casing that separates the rotor chamber from the pump chamber, and a bearing that rotatably supports a rotor shaft of the rotor and to which grease is supplied is provided. Two communication holes extend through the casing and provide fluid communication between the rotor chamber and the pump chamber.

Abstract: A centrifugal pump includes a motor portion including a rotor rotatably disposed in a rotor chamber and includes a pump portion including an impeller rotatably disposed in a pump chamber. The impeller is coupled to the rotor. The centrifugal pump also includes a casing that separates the rotor chamber from the pump chamber, and a bearing that rotatably supports a rotor shaft of the rotor and to which grease is supplied is provided. Two communication holes extend through the casing and provide fluid communication between the rotor chamber and the pump chamber.

Abstract: A motor includes a stator and a rotor having a rotor shaft. The motor includes a bearing having an inner ring and an outer ring that are configured to rotate relative to each other. The inner ring is supported by the rotor shaft. The motor also includes a holder that supports the outer ring. The holder is clearance-fitted to a retainer on a stator side. A rotation prevention apparatus configured to prevent the rotation of the holder is positioned between the holder and a stopper member on the stator side.

Abstract: A centrifugal pump includes a pump and a motor. The pump includes an impeller configured to forcibly transfer a fluid and defines a pump chamber housing the impeller therein. The motor includes a hollow rotational shaft configured to rotate the impeller, and a casing defining a motor chamber that houses the rotational shaft therein. The rotational shaft forms a discharge passage therein and has a first end engaged with the impeller and a second end where a first end of the discharge passage opens. The first end of the discharge passage is in fluid communication with a low pressure area in the pump chamber via a second end of the discharge passage and is in fluid communication with a high pressure area in the pump chamber via an introduction passage formed in the casing.