Diesel engine water pump with improved water seal
An improved diesel engine water pump includes three main features that aid in extending the maintenance-free life of the pump. The impeller shaft is carried by tapered roller shaft support bearings of which the impeller bearing has a floating outer race that is urged axially by a preload spring to provide a prescribed axial preload that maintains concentricity of the shaft with the axis and prolongs bearing life. An improved oil seal combines an oil slinger, a stationary deflector and a lip oil seal with a return passage to the engine to more effectively limit oil leakage from the pump. An improved water seal includes pressurized water jets fed from the pump volute that flush wear particles from the water seal surface and increase water seal life. Further details of these features are also disclosed.
1. A water pump of the centrifugal type adapted for use in diesel engine cooling systems, the water pump comprising:
a housing containing a shaft rotatable on an axis extending through the housing, the shaft mounting a drive member adjacent a drive end of the housing and a fluid impeller at an opposite impeller end of the housing;
axially spaced drive and impeller roller bearings mounted in an oil lubricated recess and supporting the shaft in the housing, each bearing having an inner race fixed on the shaft and an outer race mounted in the housing, the outer race of the drive bearing being fixed in the housing and oriented to transmit major thrust forces from the shaft to the housing and the outer race of the impeller bearing being axially slidable in the housing and oriented to transmit minor thrust forces to the housing;
a biasing element acting between the housing and the axially slidable outer race and preloading the impeller bearing with a selected preload force maintained on the impeller bearing to maximize bearing life and concentric rotation of the shaft over all operating conditions of the pump;
an oil control in the lubricated recess and including an oil slinger mounted on the rotatable shaft adjacent the impeller bearing and operative to centrifugally direct oil from the impeller bearing into a collector connected with an oil return passage, and a stationary oil seal including a deflector extending inward from the housing adjacent the oil slinger and operative to deflect bypassed oil into the return passage and a seal lip engaging the shaft and blocking the passage of bypassed oil along the shaft toward the fluid impeller;
a volute connected with the impeller end of the housing for receiving pressurized water from the impeller; and
a flushable water seal including a stationary water seal member having a seal surface surrounding the shaft, a rotatable water seal member mounted on the shaft and engaging the seal surface, a passage connecting the volute with a plenum, and nozzles from the plenum aimed to direct water jets against the seal surface to carry away worn particles from the seal surface and thereby increase the wear life of the water seal members.
2. A water pump of the centrifugal type adapted for use in diesel engine cooling systems, the water pump comprising:
a housing containing a shaft rotatable on an axis extending through the housing, the shaft mounting a drive member adjacent a drive end of the housing and a fluid impeller at an opposite impeller end of the housing;
a volute connected with the impeller end of the housing for receiving pressurized water from the impeller; and
a flushed water seal including a stationary water seal member having a seal surface surrounding the shaft, a rotatable water seal member mounted on the shaft and engaging the seal surface, a passage connecting the volute with a plenum to deliver pressurized water to the plenum, and nozzles extending from the plenum and aimed to direct water jets against the seal surface to carry away worn particles from the seal surface and thereby increase the wear life of the water seal members.
3. A water pump as in claim 2 wherein:
the stationary water seal member is mounted behind the impeller in the impeller end of the housing and includes a cylindrical wall connecting at one end with a radial wall carrying the seal surface;
the plenum is located adjacent the cylindrical wall; and
the nozzles extend through the cylindrical wall.
4. A water pump as in claim 2 including:
axially spaced drive and impeller bearings mounted in an oil lubricated recess and supporting the shaft in the housing, and
a stationary oil seal including a deflector extending inward from the housing adjacent the impeller bearing and operative to deflect oil into a collector connected with an oil return passage, and a seal lip engaging the shaft and blocking the passage of bypassed oil along the shaft toward the fluid impeller.
5. A water pump as in claim 2 including:
axially spaced drive and impeller bearings mounted in an oil lubricated recess and supporting the shaft in the housing; and
an oil control in the lubricated recess and including an oil slinger mounted on the rotatable shaft adjacent the impeller bearing and operative to centrifugally direct oil from the impeller bearing into a collector connected with an oil return passage.
6. A water pump as in claim 5 wherein the oil control further includes a stationary oil seal including a deflector extending inward from the housing adjacent the oil slinger and operative to deflect bypassed oil into the return passage and a seal lip engaging the shaft and blocking the passage of bypassed oil along the shaft toward the fluid impeller.
7. A water pump as in claim 6 wherein:
the stationary water seal member is mounted behind the impeller in the impeller end of the housing and includes a cylindrical wall connected at one end with a radial wall carrying the seal surface;
the plenum is located adjacent the cylindrical wall; and
the nozzles extend through the cylindrical wall.