Rotating machine

Abstract

The rotating machine includes a rotating shaft, a case surrounding the rotating shaft, the case being provided with a fluid storing chamber and formed with a housing section. The rotating machine further includes a bearing disposed in the housing section and supporting the rotating shaft, and a ring-like seal member disposed between the fluid storing chamber and the bearing for suppressing the fluid from flowing through a clearance between the rotating shaft and the case. The case is formed with a drain hole for making communication between atmosphere and a space surrounded by the seal member and the bearing within the case and discharging the fluid leaking from the fluid storing chamber and passing the seal member to enter the space, and an atmosphere introducing hole for introducing outside air into the space to keep the space at atmospheric pressure.

What is claimed is: 
     
         1 . A rotating machine comprising:
 a rotating shaft;   a case surrounding the rotating shaft, the case being provided with a fluid storing chamber for storing fluid and formed with a housing section disposed more outside in an axial direction of the rotating shaft than the fluid storing chamber;   a bearing supporting the rotating shaft, the bearing being disposed in the housing section, having an inner race, an outer race and a plurality of rolling bodies disposed between the inner and outer races, and being filled with grease; and   a ring-like seal member disposed between the fluid storing chamber and the bearing within the housing section for suppressing the fluid from flowing through a clearance between the rotating shaft and the case,   wherein   the case is formed with a drain hole disposed at a position below an axial center of the rotating shaft for making communication between atmosphere and a space surrounded by the seal member and the bearing within the case, and discharging the fluid leaking from the fluid storing chamber and passing the seal member to enter the space, and   an atmosphere introducing hole for introducing outside air into the space to keep the space at atmospheric pressure.   
     
     
         2 . The rotating machine according to  claim 1 , wherein an end surface of the outer race on the side of the seal member coincides with an edge of the drain hole on the side of the bearing or projects inside an opening of the drain hole. 
     
     
         3 . The rotating machine according to  claim 1 , wherein an outer periphery of the outer race of the bearing on the side of the seal member is chamfered to have a chamfered portion, the chamfered portion being located inside the opening of the drain hole. 
     
     
         4 . The rotating machine according to  claim 1 , wherein the bearing includes a seal plate for sealing between a space surrounded by the inner and outer races and the space surrounded by the seal member and the bearing. 
     
     
         5 . The rotating machine according to  claim 1 , wherein
 the housing section is a circular bore formed in the case having an inner diameter larger than a diameter of the rotating shaft,   the seal member and the bearing are fitted into the housing section in succession,   the inner diameter of the housing section is reduced at a diameter-reduced portion thereof portion in which the seal member is disposed, and   the case is tapered to have a tapered surface at a boundary between the diameter-reduced portion and a portion in which the bearing is disposed, the tapered surface overlapping with the drain hole.   
     
     
         6 . The rotating machine according to  claim 1 , wherein the drain hole and the atmosphere introducing holes are circular holes having the same diameter.