Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
  • F16C19/00—Bearings with rolling contact, for exclusively rotary movement
  • F16C19/54—Systems consisting of a plurality of bearings with rolling friction
  • F16C19/546—Systems with spaced apart rolling bearings including at least one angular contact bearing
  • F16C19/547—Systems with spaced apart rolling bearings including at least one angular contact bearing with two angular contact rolling bearings
  • F16C19/548—Systems with spaced apart rolling bearings including at least one angular contact bearing with two angular contact rolling bearings in O-arrangement
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
  • F16C19/00—Bearings with rolling contact, for exclusively rotary movement
  • F16C19/22—Bearings with rolling contact, for exclusively rotary movement with bearing rollers essentially of the same size in one or more circular rows, e.g. needle bearings
  • F16C19/34—Bearings with rolling contact, for exclusively rotary movement with bearing rollers essentially of the same size in one or more circular rows, e.g. needle bearings for both radial and axial load
  • F16C19/36—Bearings with rolling contact, for exclusively rotary movement with bearing rollers essentially of the same size in one or more circular rows, e.g. needle bearings for both radial and axial load with a single row of rollers
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
  • F16C23/00—Bearings for exclusively rotary movement adjustable for aligning or positioning
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
  • F16C25/00—Bearings for exclusively rotary movement adjustable for wear or play
  • F16C25/06—Ball or roller bearings
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
  • F16C25/00—Bearings for exclusively rotary movement adjustable for wear or play
  • F16C25/06—Ball or roller bearings
  • F16C25/08—Ball or roller bearings self-adjusting
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
  • F16C19/00—Bearings with rolling contact, for exclusively rotary movement
  • F16C19/22—Bearings with rolling contact, for exclusively rotary movement with bearing rollers essentially of the same size in one or more circular rows, e.g. needle bearings
  • F16C19/30—Bearings with rolling contact, for exclusively rotary movement with bearing rollers essentially of the same size in one or more circular rows, e.g. needle bearings for axial load mainly

Definitions

• This invention relates generally to bearing units for rotatable shafts which are subject to high loadings. More particularly, the present invention is directed to devices for pre-loading a pair of axially spaced radial bearings for a rotatable shaft.
• the bearing unit in order to achieve a substantially play-free shaft/bearing configuration, the bearing unit must be adapted to take into account both axial loading as well as radial loading.
• the axial loading on the shaft is often proportional to the radial loading.
• One conventional proposal to account for the axial/radial loading conditions is to incorporate tandem radial bearing units which are oriented in opposed relationship to the shaft.
• the outer rings of the bearing units are pre-loaded against each other by a spring assembly. While such units have proved to be advantageous, such units are substantially play- free in the axial direction.
• a limited axial displacement may be desirable for a number of reasons, including the accommodation of thermal expansion, which may be not insignificant when the shaft is subjected to intense loading conditions.
• Some constructions have addressed the axial displacement problem by mounting the bearings within a bearing housing. Under certain conditions, the bearing housing is axially displaceable within a second primary housing. Another approach to allowing for limited axial displacement is to mount the radial bearings in a separate bearing seat. A pre-loading device is disposed between the bearing seats to allow limited axial displacement in the bearing housing. The bearing seats are thus axially displaceable within the stationary bearing housing assembly.
• the pre-loading force is implemented by spring units
• the pre-loading force can vary during operation, especially as a result of varying operating temperatures. Consequently, if the bearings are not in close proximity, the spring pre ⁇ loaded bearing units may represent an impractical design approach. It is also established that in most applications, the applied radial loads can vary throughout the operation. The variability in the axial loads also may result in an associated axial pre-loading which increases or decreases proportionally.
• bearings for the shaft are pre-loaded by hydraulic systems.
• U.S. Patent 3,574,424 discloses an axial loaded bearing wherein a pair of axially spaced bearings are axially loaded by a circulating oil pressure system.
• the invention in a preferred form is a controllable pre-loadabie bearing unit for a rotatable shaft assembly which is housed for rotation.
• a first bearing unit radially bears against the shaft assembly.
• the bearing unit is mounted in a seat which is received in the housing.
• a chamber associated with the first seat defines a pressure chamber for exerting an axial pre-loading pressure against the seat in a first axial direction.
• a second bearing unit is axially spaced from the first bearing unit for providing a second radial bearing interface for the shaft assembly.
• a second seat for the second bearing is disposed in the housing, and the second chamber is associated with the second seat to define a second pressure chamber for exerting an axial pre-loading pressure against the second seat in a second axial direction which is opposite the first direction.
• a communication line provides pressure communication between the two chambers.
• a pressure accumulator communicates with the line to pressurize the two chambers.
• Each of the pressure chambers is defined by a portion of the seat, the housing and the associated seal rings. These seats are substantially identical but oppositely axially oriented with respect to the housing and shaft assembly.
• a regulator communicates with the pressure accumulator to regulate the pre-loading pressure in the chambers. Axial displacement of the shaft and/or a radial bearing unit is possible without affecting the pre-loading force exerted against the bearing unit.
• An object of the invention is to provide a new and improved device for a radial bearing unit which may be axially pre-loaded in an efficient and controlled manner.
• Another object of the invention is to provide a new and improved device for a radial bearing unit for a rotor shaft assembly which implements an axial pre-loading while permitting limited axial displaceability of the shaft assembly.
• a further object of the invention is to provide a device for a radial bearing unit for a rotor shaft assembly which accommodates axial loading-induced displacement of the shaft while maintaining a substantially constant axial pre-load force on the radial bearing units.
• Figure 1 is a central sectional view, partly in schematic, of an apparatus incorporating a pre-loading device for a radial bearing unit in accordance with the present invention
• Figure 2 is an enlarged fragmentary sectional view, partly in schematic and partly in phantom, of the apparatus of Figure 1 further illustrating the axial loading characteristics of the invention.
• an apparatus which incorporates a shaft and a controllable pre-loading device for a radial bearing unit for an axle or rotor shaft is generally designated by the numeral 10.
• the shaft 12 may be exemplary of any of a number of rotatable drive shafts which may mount a working head or member that is subject to intense loading during operation.
• the shaft 12 is rotatably mounted within the housing 20 for rotation about axis A.
• the invention is particularly suited for use in a disc refiner for ligno-cell ⁇ losic material.
• Two axially spaced radial bearing units designated generally by the numerals 30 and 50 are mounted to the shaft 12 to provide a radial bearing interface for the shaft.
• Each of the bearing units 30, 50 has an outer ring 32, 52 which mounts a circular array of roller bearings 34, 54.
• the roller bearings engage an inner race ring 14, 16 which is axially and rotatably fixed to the shaft or integral with the shaft.
• Each of the outer rings 32, 52 of the bearing units is received in respective seats 40, 60 which are received within the housing.
• the seats 40, 60 are substantially identical.
• the seats are axially displaceable relative to the housing but are rotationally keyed or fixed to the housing.
• the outer rings 32, 52 are axially fixed in relation to the respective seats 40, 60.
• the housing 20 includes a central inner annular platform 22 which is defined by a pair of opposite annular radial shoulders 24, 26.
• Each of the seats 40, 60 has a stepped outer cylindrical surface of enlarged and reduced diameter and an annular radially extending shoulder 42, 62. Shoulders 24, 26 and 42, 62 are substantially equal in dimensions to provide a close-fitting relationship between the seats and the housing.
• Seal rings 27, 28 mounted in circumferential grooves of the seats seal each of the outer seat surfaces with the inner wall of the bearing housing and the platform, respectively, so as to provide a fluid tight chamber 44, 64 between the opposed annular seat shoulders 42, 62 and the platform shoulders 24, 26 as well as portions of the inner cylindrical wall of the housing and the outer wall of the reduced cylindrical surface.
• a hydraulic pressure line 48 connects the passages and also communicates with a hydraulic accumulator 70.
• a pressure regulator 72 such as a relief valve, relief line or other type pressure regulator, connects with the accumulator for regulating the hydraulic pressure in the accumulator and hence controlling the hydraulic pressure which is supplied to each of the hydraulic chambers 44, 64.
• the axial pre-loading of each of the bearing units 30, 50 is controllably determined by the hydraulic pressure in the respective chambers 44, 64.
• the chambers are configured so that the pressure exerts an effective equivalent pre-loading pressure on the seat shoulders 42, 62 in opposing axial directions.
• the pressure in the accumulator, and thus the axial pre-loading, is preset by the pressure regulator 72.
• the seat shoulder areas in the pressure chambers which are subject to the axial loading pressure are substantially equal in size. Since each of the chambers is connected to a common pressure line 48 which is pressurized by the accumulator 70, the axial pre-loading pressure is constant and equal for each of the bearing units 30, 50. With reference to Figure 2, the pre-loading device is illustrated for a circumstance wherein an intense axial load in the direction of the heavy arrow is applied to the rotor shaft 12. The bearing seats 30, 50 and thus the bearing units are free to move in limited fashion axially in opposition to the pre-loading forces (as illustrated by the phantom lines).

Landscapes

• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Magnetic Bearings And Hydrostatic Bearings (AREA)
• Support Of The Bearing (AREA)

Applications Claiming Priority (3)

Publications (2)

Family

ID=20397769

Family Applications (1)

Country Status (5)

Cited By (1)

Families Citing this family (1)

Citations (1)

Family Cites Families (4)

• 1995
  • 1995-03-31 SE SE9501170A patent/SE506134C2/sv not_active IP Right Cessation
• 1996
  • 1996-03-13 EP EP96910438A patent/EP0861382A1/en not_active Withdrawn
  • 1996-03-13 WO PCT/US1996/003396 patent/WO1996030661A1/en not_active Application Discontinuation
  • 1996-03-13 CA CA002216706A patent/CA2216706C/en not_active Expired - Fee Related
• 1997
  • 1997-09-24 NO NO974410A patent/NO974410D0/no unknown

Patent Citations (1)

Non-Patent Citations (1)

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