Propeller-shaped impeller and railway carriage air-conditioning apparatus

Abstract

A boss fitted to a rotation shaft of a motor is placed on a bearing surface. An airflow producing unit includes blades protruding from the boss in a radial direction of the shaft and rotating with the boss. The boss includes a first end surface to contact the bearing surface when fitted to the shaft with a first end of the boss in a thickness direction facing the bearing surface, and a second end surface to contact the bearing surface when fitted to the shaft with a second end of the boss in the thickness direction facing the bearing surface. A degree of symmetry defined by A/B falls within a range of 1.0 to 1.3, where A is a height of the airflow producing unit from the first end surface, B is a height of the airflow producing unit from the second end surface, and A B.

1 . A propeller-shaped impeller, comprising:
 a boss rotatable with a rotation shaft of a motor having a bearing surface from which the rotation shaft protrudes, the boss being configured to be placed on the bearing surface as being fitted to the rotation shaft of the motor; and   an airflow producing unit including a plurality of blades protruding from the boss outwardly in a radial direction of the rotation shaft and rotatable together with the boss to produce an airflow,   wherein the boss includes a first end surface configured to come in contact with the bearing surface when the boss is fitted to the rotation shaft with one end of the boss in a thickness direction parallel to the rotation shaft facing the bearing surface, and a second end surface configured to come in contact with the bearing surface when the boss is fitted to the rotation shaft with another end of the boss in the thickness direction facing the bearing surface, and   a degree of symmetry defined by A/B falls within a range of 1.0 to 1.3 inclusive, where A is a height of the airflow producing unit from one end surface of the first end surface and the second end surface, B is a height of the airflow producing unit from another end surface of the first end surface and the second end surface, and A B.   
     
     
         2 . The propeller-shaped impeller according to  claim 1 , wherein
 a sum of the height A of the airflow producing unit from the one end surface and the height B of the airflow producing unit from the another end surface is not greater than 115 mm, and   the airflow producing unit has a forward inclination angle.   
     
     
         3 . The propeller-shaped impeller according to  claim 1 , wherein
 a sum of the height A of the airflow producing unit from the one end surface and the height B of the airflow producing unit from the another end surface is not greater than 115 mm, and   the airflow producing unit has a stagger angle of not greater than 75°.   
     
     
         4 . The propeller-shaped impeller according to  claim 1 , wherein
 a sum of the height A of the airflow producing unit from the one end surface and the height B of the airflow producing unit from the another end surface exceeds 115 mm, and   the airflow producing unit has a cutout to avoid contact with the motor.   
     
     
         5 . The propeller-shaped impeller according to  claim 1 , wherein an aspect ratio defined by C/D falls within a range of 0.10 to 0.16 inclusive, where C is a total height of the airflow producing unit and D is a diameter of the airflow producing unit. 
     
     
         6 . A railway carriage air-conditioning apparatus, comprising:
 an outdoor heat exchanger having a structure to allow refrigerant to flow inside and configured to exchange heat with air;   an outdoor blower including the propeller-shaped impeller according to  claim 1 , and the motor to which the propeller-shaped impeller is attached, and configured to take in air from outside a railway carriage, cause the air to pass through the outdoor heat exchanger, and discharge the air out of the railway carriage; and   a collaborative system to provide a refrigerating cycle together with the outdoor heat exchanger using the refrigerant.