Centrifugal separator with weight thrust bearing

Abstract

A self-powered centrifugal separator, for separating particulate contaminants from a liquid lubricant of an automobile engine, includes a rotor container rotatable about an axle to which it is journalled by bushes. When the engine is running, a film of pressurized liquid between the bushes and axle lubricates them and provides radial stiffness, but when the engine stops and liquid supply ceases, radial stiffness is reduced and the partially emptying container may vibrate and create wind-down noise. At least one bush, which normally provides a horizontal thrust bearing to support the weight of the container at low speed, has, with the axle portion it surrounds, a region tapering in diameter to center the container with respect to the axle and provide both radial and axial support.

1. A centrifugal separator comprising a housing, axle means extending along the housing substantially vertically and defining a rotation axis, a rotor rotatable about the rotation axis about said axle means and including an upper bush and a lower bush at respective upper and lower ends of said axle means, said upper bush and said lower bush each surrounding the axle means defining a journal bearing, and each being exposed to  constructed to receive lubricant supplied to the rotor such that  allowing lubricant can  to pass between said upper bush and said lower bush and said axle means to form therein a film, at least one of said upper bush and said lower bush providing weight thrust bearing means operable to support the weight of the rotor, at least during wind-down, the weight thrust bearing means comprising at least one portion of said axle means tapering from a lower region of greater diameter to an upper region of lesser diameter and said at least one of said upper bush and said lower bush surrounding the portion conforming to the taper and defining a combined journal and thrust bearing whereby the rotor carried by the thrust bearing is centered with respect to the axle means and supported both radially and axially, wherein the rotor includes an upper wall and a lower wall, the upper wall having an upper aperture and the lower wall having a lower aperture, wherein the upper bush is disposed within the upper aperture and the lower bush is disposed within the lower aperture, wherein the upper wall and upper bush and the lower wall and lower bush define a container for receiving a pressurized fluid, wherein the lower bush has a greater inner diameter than the upper bush, and wherein, when the container is filled with a pressurized fluid, the force created by the pressurized fluid and acting on the upper wall and upper bush is greater than the force created by the pressurized fluid and acting on the lower wall and lower bush because of the difference in inner diameter between the lower and upper bushes, thereby pushing the rotor upwards. 
     
     
       2. A centrifugal separator as claimed in  claim 1  in which the end of the upper bush exposed to lubricant pressure has a lesser inner diameter than the upper end of the lower bush such that in normal operation lubricant supply pressure acts to separate the conforming tapered surfaces of the weight thrust bearing means. 
     
     
       3. A centrifugal separator as claimed in  claim 1  in which the weight thrust bearing means is defined in both upper and lower bushes. 
     
     
       4. A centrifugal separator comprising a housing, axle means extending along the housing substantially vertically and defining a rotation axis, a rotor rotatable about the rotation axis about said axle means and including an upper bush and a lower bush at respective ends of said axle means, said upper bush and said lower bush each surrounding the axle means defining a journal bearing, and each being exposed to lubricant supplied to the rotor such that lubricant can pass between said upper bush and said lower bush and said axle means to form therein a film, one of said upper bush and said lower bush at one of said respective ends of said axle means exposing a greater face area to said lubricant than the other of said upper bush and said lower bush such that, when the lubricant is under pressure, said rotor will move toward one of said respective ends of said axle means; and a weight thrust bearing at the other of said respective ends of said axle means for supporting said rotor when the lubricant pressure is reduced, said weight thrust bearing including cooperating tapered surfaces on said axle means and the other of said upper bush and said lower bush. 
     
     
       5. A rotor for use with a centrifugal separator, the centrifugal separator including a housing and an axle extending along the housing substantially vertically and defining a rotation axis, at least one portion of the axle tapering from a lower region of greater diameter to an upper region of lesser diameter, comprising:
   a container including an upper wall and a lower wall, the upper wall having an upper aperture and the lower wall having a lower aperture, the upper and lower apertures being aligned on a longitudinal axis of the container; and        an upper bush disposed within the upper aperture and a lower bush disposed within the lower aperture, at least one of the upper bush and the lower bush including a taper on a lower inner portion thereof tapering from an upper region of lesser diameter to a lower region of greater diameter, wherein the upper wall and upper bush and the lower wall and lower bush define a chamber for receiving a pressurized fluid;        wherein the lower bush has a greater inner diameter than the upper bush, and wherein, when the container is filled with a pressurized fluid, the force created by the pressurized fluid and acting on the upper wall and upper bush is greater than the force created by the pressurized fluid and acting on the lower wall and lower bush because of the difference in inner diameter between the lower and upper bushes, thereby pushing the rotor upwards;        wherein the upper bush and the lower bush are each adapted to surrounding the axle of the centrifugal separator to define a respective journal bearing when the rotor is installed in the centrifugal separator;        wherein when the rotor is installed in the centrifugal separator, the rotor is adapted to being rotatable about the rotation axis about the axle; and        wherein at least one of the upper bush and the lower bush is adapted to, when the rotor is installed in the centrifugal separator, providing a weight thrust bearing being adapted to supporting the weight of the rotor, at least during wind - down, the weight thrust bearing formed from the at least one portion of the axle tapering from a lower region of greater diameter to an upper region of lesser diameter and a respective one of the upper bush and the lower bush with a taper conforming to the tapered axle portion, the respective tapered upper or lower bush surrounding the tapered portion of the axle to define a combined journal and thrust bearing whereby the rotor carried by the thrust bearing is centered with respect to the axle and supported on the axle both radially and axially.     
     
     
       6. A rotor as claimed in  claim 5 , wherein each of the bushes is adapted to being exposed to lubricant supplied to the rotor such that lubricant can pass between the upper bush and the lower bush and the axle to form therein a film. 
     
     
       7. A rotor as claimed in  claim 5 , wherein the weight thrust bearing is defined in both upper and lower bushes. 
     
     
       8. A rotor as claimed in  claim 5 , further comprising a hollow member extending from the lower aperture to the upper aperture, wherein the hollow member is in fluid communication with the container, wherein an end of the hollow member is placed in the lower aperture and another end is placed in the upper aperture, and wherein the upper bush is disposed within the upper end of the hollow member and the lower bush is disposed within the lower end of the hollow member. 
     
     
       9. A rotor for use with a centrifugal separator, the centrifugal separator including an axle, at least a first portion of the axle tapering from a lower region of greater diameter to an upper region of lesser diameter, comprising:
   a container including an upper wall and a lower wall, the upper wall having an upper aperture and the lower wall having a lower aperture, the upper and lower apertures being aligned on a longitudinal axis of the container;        an upper bush having an inner diameter, the inner diameter including a taper on a lower portion thereof from an upper region of lesser diameter to a lower region of greater diameter, the upper bush disposed within the upper aperture; and        a lower bush having an inner diameter, the lower bush disposed within the lower aperture;        wherein the inner diameter of the lower bush is greater than the inner diameter of the upper bush, wherein the upper wall and upper bush and the lower wall and lower bush define a chamber for receiving a pressurized fluid, and wherein, when the container is filled with a pressurized fluid, the force created by the pressurized fluid and acting on the upper wall and upper bush is greater than the force created by the pressurized fluid and acting on the lower wall and lower bush because of the difference in inner diameter between the lower and upper bushes, thereby pushing the rotor upward; and        wherein when in an operable configuration with the centrifugal separator, the axle is adapted to being disposed through the first and second bushes, the taper of the first bush surrounding the taper of the first portion of the axle to form a weight thrust bearing.     
     
     
       10. The rotor of  claim 9 , wherein the inner diameter of the upper bush includes a taper on a lower portion thereof from an upper region of lesser diameter to a lower region of greater diameter and wherein the taper of the upper bush is adapted to surrounding a taper of an upper portion of the axle from a lower region of greater diameter to an upper region of lesser diameter to form an upper weight thrust bearing when the rotor is installed in the centrifugal separator. 
     
     
       11. The rotor of  claim 9 , wherein the inner diameter of the lower bush includes a taper on a lower portion thereof from an upper region of lesser diameter to a lower region of greater diameter and wherein the taper of the lower bush is adapted to surrounding a taper of a lower portion of the axle from a lower region of greater diameter to an upper region of lesser diameter to form a lower weight thrust bearing when the rotor is installed in the centrifugal separator. 
     
     
       12. A rotor of  claim 9 , further comprising a hollow member extending from the lower aperture to the upper aperture, wherein the hollow member is in fluid communication with the container, wherein an end of the hollow member is placed in the lower aperture and another end is placed in the upper aperture, and wherein the upper bush is disposed within the upper end of the hollow member and the lower bush is disposed within the lower end of the hollow member. 
     
     
       13. A rotor, comprising:
   a container including an upper wall and a lower wall, the upper wall having an upper aperture and the lower wall having a lower aperture, the upper and lower apertures being aligned on a longitudinal axis of the container;        an upper bush having an inner diameter, the inner diameter including a taper on a lower portion thereof from an upper region of lesser diameter to a lower region of greater diameter, the upper bush disposed within the upper aperture; and        a lower bush having an inner diameter, the lower bush disposed within the lower aperture;        wherein the inner diameter of the lower bush is greater than the inner diameter of the upper bush, wherein the upper wall and upper bush and the lower wall and lower bush define a chamber for receiving a pressurized fluid, and wherein, when the container is filled with a pressurized fluid, the force created by the pressurized fluid and acting on the upper wall and upper bush is greater than the force created by the pressurized fluid and acting on the lower wall and lower bush because of the difference in inner diameter between the lower and upper bushes, thereby pushing the rotor upwards.     
     
     
       14. The rotor of  claim 13 , wherein the inner diameter of the upper bush includes a taper on a lower portion thereof from an upper region of lesser diameter to a lower region of greater diameter. 
     
     
       15. The rotor of  claim 13 , wherein the inner diameter of the lower bush includes a taper on a lower portion thereof from an upper region of lesser diameter to a lower region of greater diameter. 
     
     
       16. A rotor of  claim 13 , further comprising a hollow member extending from the lower aperture to the upper aperture, wherein the hollow member is in fluid communication with the container, wherein an end of the hollow member is placed in the lower aperture and another end is placed in the upper aperture, and wherein the upper bush is disposed within the upper end of the hollow member and the lower bush is disposed within the lower end of the hollow member. 
     
     
       17. A rotor, comprising:
   a container including an upper wall and a lower wall, the upper wall having an upper aperture and the lower wall having a lower aperture, the upper and lower apertures being aligned on a longitudinal axis of the container;        a lower bush having a taper on a lower portion of an inner diameter of the lower bush, the lower bush disposed within the lower aperture; and        an upper bush having an inner diameter, the upper bush disposed within the upper aperture;        wherein the inner diameter of the lower bush is greater than the inner diameter of the upper bush, wherein the upper wall and upper bush and the lower wall and lower bush define a chamber for receiving a pressurized fluid, and wherein, when the container is filled with a pressurized fluid, the force created by the pressurized fluid and acting on the upper wall and upper bush is greater than the force created by the pressurized fluid and acting on the lower wall and lower bush because of the difference in inner diameter between the lower and upper bushes, thereby pushing the rotor upwards.     
     
     
       18. The rotor of  claim 17 , wherein the inner diameter of the upper bush includes a taper on a lower portion thereof. 
     
     
       19. A rotor of  claim 17 , further comprising a hollow member extending from the lower aperture to the upper aperture, wherein a larger end of the hollow member is placed in the lower aperture and a smaller end is placed in the upper aperture, and wherein the upper bush is disposed within the smaller upper end of the hollow member and the lower bush is disposed within the larger lower end of the hollow member.