Patent Publication Number: US-2010108932-A1

Title: Bearing assembly and a method for controlling fluid flow within a conduit

Description:
BACKGROUND OF THE INVENTION 
     The field of the disclosure relates generally to valve assemblies, more particularly to tapered roller bearings used in butterfly valve shaft housings. 
     Butterfly valves are one of many types of valves that are used to control the flow of fluids within a conduit. More specifically, some known butterfly valves include a disc (also known as a “butterfly”) that is rotated within a fluid flow conduit for use in controlling fluid flowing therethrough in varying amounts. In such known systems, the disc includes two shafts that extend radially outward from the disk and that are coupled substantially circumferentially opposite one another. Each shaft is received within a shaft housing such that the disk may rotate on an axis that traverses the conduit between an open position and a closed position. When the disc is in the open position, the plane of the disc is substantially coincident or parallel to the direction of flow such that the fluid flow rate may be maximized therethrough. When the disc is in the closed position, the plane of the disc is substantially transverse/orthogonal to the direction of flow such that the fluid flow rate may be minimized or completely blocked. 
     Some known butterfly valve assemblies include a bearing assembly positioned within the shaft housing that receives each shaft therethrough and provides for a substantially smooth rotation of the disk between the open and closed position. In such assemblies, the bearing assembly includes a plurality of spherical bearings positioned within a bearing race that facilitates reducing friction as the shift rotates within the housing. 
     Some known discs may be alternatively mounted obliquely within the conduit such that one shaft housing is positioned upstream of the other such that the plane of the disc may be offset at an angle with respect to the direction of flow. When encountering a flow when placed in the closed position, the disk experiences a load that is translated as an axial force acting along the rearwardly located shaft. However, the disk in such systems should not experience any noticeable axial displacement as it must return to same position each time it returns to the closed position. Known systems that use round roller bearings within the bearing assemblies experience an axial displacement of the disk and therefore lack an axial position control suitable for systems that use an obliquely mounted butterfly valve disk. 
     BRIEF DESCRIPTION OF THE INVENTION 
     In one aspect, a valve system is provided. The valve system includes a conduit having a flow of fluid therethrough, and a butterfly valve assembly. The butterfly valve assembly includes a shaft extending obliquely within the conduit, a butterfly disk, and a first bearing assembly positioned on an external surface of the conduit. The butterfly disk includes a passage sized to receive the shaft therethrough, wherein the butterfly disk is operable to restrict the fluid flow through the conduit when the butterfly valve assembly is in the closed position. The first bearing assembly is configured to receive a first end of the shaft therethough, wherein the first bearing assembly includes a plurality of tapered roller bearings circumferentially-spaced within a bearing race and configured to maintain the butterfly disk at a substantially constant axial position when the butterfly valve assembly is in the closed position. 
     In another aspect, a bearing assembly is provided. The bearing assembly is configured to receive a first end of a shaft therethough, wherein the first bearing assembly includes a plurality of tapered roller bearings circumferentially-spaced within a bearing race and configured to maintain a butterfly valve assembly at a substantially constant axial position when the butterfly valve assembly is in the closed position. 
     In yet another aspect, a method for controlling a flow of fluid within a conduit is provided. The method includes positioning a butterfly valve assembly within the conduit such that a shaft extends obliquely within the conduit, wherein the butterfly valve assembly includes a butterfly disk operable between an open and closed position. The method also includes maintaining a butterfly disk at a substantially constant axial position using a plurality of tapered roller bearings circumferentially spaced within at least one bearing assembly positioned on an external surface of the conduit. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Non-limiting and non-exhaustive embodiments are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various views unless otherwise specified. 
         FIG. 1  is a schematic illustration of an exemplary anti-ice system used in an exemplary aircraft. 
         FIG. 2  is a sectional view of an exemplary valve system used with the exemplary anti-ice system shown in  FIG. 1 . 
         FIG. 3  is a perspective view of an exemplary bearing assembly used with the exemplary valve system shown in  FIG. 2 . 
         FIG. 4  a sectional view of the exemplary bearing assembly. 
         FIG. 5  is an end view of an exemplary bearing race used with bearing assembly shown in  FIG. 3 . 
         FIG. 6  is a sectional view along line  6 - 6  shown in  FIG. 5  of an exemplary bearing race used with bearing assembly shown in  FIG. 3 . 
         FIG. 7  is an end view of an exemplary tapered roller bearing used with bearing assembly shown in  FIG. 3 . 
         FIG. 8  is a sectional view along line  8 - 8  shown in  FIG. 7  of an exemplary tapered roller bearing used with bearing assembly shown in  FIG. 3 . 
         FIG. 9  is an end view of an exemplary bearing cage used with bearing assembly shown in  FIG. 3 . 
         FIG. 10  is a sectional view along line  10 - 10  shown in  FIG. 9  of an exemplary bearing cage used with bearing assembly shown in  FIG. 3 . 
         FIG. 11  is an end view of an exemplary outer bearing ring used with bearing assembly shown in  FIG. 3 . 
         FIG. 12  is a sectional view along line  12 - 12  shown in  FIG. 11  of an exemplary outer bearing ring used with bearing assembly shown in  FIG. 3 . 
         FIG. 13  is a flow diagram for method of controlling a flow of fluid within a conduit. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  is a schematic illustration of an exemplary aircraft  100  that includes in an exemplary anti-ice system  110 . In the exemplary embodiment, an aircraft  100  includes a fuselage  120  and a wing  130  extending therefrom, and includes a gas turbine engine  140  coupled to wing  130 . Anti-ice system  110  includes a conduit  150  that extends from engine  140  along a leading edge  160  of wing  130  that is sized and oriented to channel a flow of high temperature bleed air  170  from engine  140  along leading edge  160  to substantially prevent accumulation of ice on wing  130  during cold weather conditions and/or while in flight. Anti-ice system  110  includes a valve assembly  180  that regulates the flow of bleed air  170  from engine  140  along leading edge  160 . Alternatively, valve assembly  180  may be positioned within any aircraft system and along any conduit within aircraft, or any other vehicle, that requires pressure regulating and control of a fluid therethrough. 
       FIG. 2  is a sectional view of an exemplary valve system  200  used with anti-ice system  110  shown in  FIG. 1 . In the exemplary embodiment, valve system  200  is positioned within conduit  202 , as described in more detail herein. Valve system  200  includes a butterfly disk  204  positioned within conduit  202  and sized to substantially minimize a fluid flow, indicated by arrow  206 , through conduit  202  when butterfly disk  204  is in a closed position, as shown in  FIG. 2 . A shaft  208  extends through a passage  210  defined within butterfly disk  204  that is sized and oriented to rotate butterfly disk  204  between an open and the closed position. More specifically, and in the exemplary embodiment, shaft  208  extends a length L 1  through a bore  212  in conduit  202  at a first location  214 , and similarly extends a length L 2  through a bore  216  in conduit  202  and at a radially opposite second location  218 . In the exemplary embodiment, a first bearing assembly  220  is positioned within a corresponding bearing cover  222  on an external surface  224  of conduit  202  and is sized and oriented to receive a first end  226 , and length L 1 , of shaft  208  therein. Similarly, a second bearing assembly  230  is positioned in a corresponding bearing cover  232  on external surface  224  of conduit  202  and is sized and oriented to receive an opposite second end  234 , and length L 2 , of shaft  208  therein. During operation, bearing assemblies  220 ,  230  provide for a substantially frictionless rotation of butterfly disk  204  when butterfly disk  204  is rotated between the open and closed position, as described in more detail herein. 
     As illustrated in  FIG. 2 , shaft  208  extends through conduit  202  at an angle α 1  measured from a central axis  240 . In the exemplary embodiment, angle α 1  is approximately 80°. Alternatively, angle α 1  may be an angle ranging from about 75° to about 85°, or any angle that enables valve assembly  200  to function as described herein. 
       FIG. 3  is a perspective view, and  FIG. 4  is a sectional view, of an exemplary bearing assembly  300 , such as for example first bearing assembly  220  and/or second bearing assembly  230 , used with valve system  200  shown in  FIG. 2 . In the exemplary embodiment, bearing assembly  300  includes a inner bearing race  310 , a plurality of tapered roller bearings  320  positioned within bearing race  310 , a bearing cage  330  that receives and maintains each of the plurality of roller bearings  320  in a circumferential position around inner bearing race  310 , as described herein. Bearing assembly includes an outer bearing ring  340  that receives inner bearing race  310 , tapered roller bearings  320  and cage  330  therein, as described in more detail herein. 
       FIG. 5  is an end view, and  FIG. 6  is a sectional view of an exemplary bearing race  310  used with bearing assembly  300  shown in  FIG. 3 . In the exemplary embodiment, bearing race  310  is substantially cylindrical in cross-section and includes an aperture  350  that is sized and oriented to receive shaft  208  therethrough, as shown in  FIG. 2 . In the exemplary embodiment, bearing race  310  includes a diameter D 1  at a first end  352  and a diameter D 2  at a second end  354 , wherein D 2  is greater than D 1  such that an obliquely oriented surface  356  extends between first end  352  and second end  354 . Oblique surface  356  is offset from an axis of rotation  358  at an angle α 2 . In the exemplary embodiment, angle α 2  is approximately 15°. Alternatively, bearing race  310  is sized and oriented to enable bearing assembly  300  to function as described herein. 
     In the exemplary embodiment, bearing race  310  includes a channel  360  that extends a length L 3  over oblique surface  356 . Channel  360  is sized and oriented to receive tapered roller bearings  320  therein, as described in more detail herein, and as shown for example in  FIG. 3 . Bearing race  310  includes a first flange  362  positioned adjacent to bearing race first end  352  that maintains tapered roller bearing  320  within channel  360 . Similarly, bearing race  310  includes a second flange  364  positioned adjacent to bearing race second end  354  that further maintain tapered roller bearing  320  within channel  360 . Alternatively, bearing race  310  may include any lip, extension or retention element that will substantially maintain tapered roller bearings  320  within channel  360  and that will enable bearing assembly  300  to function as described herein. 
       FIG. 7  is an end view and  FIG. 8  is a sectional view of an exemplary tapered roller bearing  320  used with bearing assembly  300  shown in  FIG. 3 . In the exemplary embodiment, tapered roller bearing  320  is substantially conical in cross-section. More specifically, tapered roller bearing  320  includes a first end  370  having a diameter D 3  and a second end  372  having a diameter D 4 , wherein, in the exemplary embodiment, D 4  is greater than D 3 . Tapered roller bearing  320  includes an outer surface  374  that is substantially smooth in contour and that includes a length L 4  such that tapered roller bearing  320  fits within bearing race channel  360 , as shown in  FIG. 6 . 
     In the exemplary embodiment, tapered roller bearing  320  is fabricated from a heat treated  440 C stainless steel that is machined using a turning process. Alternatively, tapered roller bearing may be fabricated from any corrosion resistant material that may be used in temperatures of up to approximately 650° F. 
       FIG. 9  is an end view and  FIG. 10  is a sectional view of an exemplary bearing cage  330  used with bearing assembly  300  shown in  FIG. 3 . In the exemplary embodiment, bearing cage  330  is substantially conical in cross-section. More specifically, bearing cage  330  includes a first end  380  having a diameter D 5  and a second end  382  having a diameter D 6 , wherein, in the exemplary embodiment, D 6  is greater than D 5 . In the exemplary embodiment, bearing cage  330  includes an aperture  383  that is sized and oriented to receive bearing race  310  (shown in  FIG. 3 ) therethrough. In the exemplary embodiment, bearing cage  330  includes a plurality of circumferentially-spaced receptacles  384  that are sized and oriented to receive a corresponding number of tapered roller bearings  320  therein, as shown in  FIG. 3 . Moreover, bearing cage  330  is sized such that diameter D 5  is greater than bearing race diameter D 1 , and such that bearing cage  330  will receive bearing race  310  and tapered roller bearings  320  therein when tapered roller bearings  320  are positioned within channel  360 . 
     In the exemplary embodiment, bearing cage  330  is fabricated from an aluminum/bronze alloy using a machining process. Alternatively, bearing cage may be fabricated from any corrosion resistant material that may be used in temperatures of up to approximately 650° F. 
       FIG. 11  is an end view and  FIG. 12  is a sectional view of an exemplary outer bearing ring  340  used with bearing assembly  300  shown in  FIG. 3 . In the exemplary embodiment, outer bearing ring  340  is substantially circular and is sized and configured to receive bearing race  310 , tapered roller bearings  320  and bearing cage  330  therein. More specifically and in the exemplary embodiment, outer bearing ring  340  includes an inner track surface  390  that is sized and oriented to receive tapered roller bearings  320  when tapered roller bearings  320  are positioned within corresponding channel  360  and receptacles  384 , shown in  FIGS. 3 and 4 . Inner track surface  390  includes an angle α 3  that is substantially equivalent to an angle α 4  (shown in  FIG. 4 ) defined by tapered roller bearings  320  when positioned within corresponding channel  360  and receptacle  384 . 
       FIG. 13  is a flow diagram for method  400  of controlling a flow of fluid within a conduit, such as for example conduit  150  shown in  FIG. 1 . In the exemplary embodiment, method  400  includes positioning  410  a butterfly valve assembly within the conduit such that a shaft extends obliquely within the conduit, as described herein. The butterfly valve assembly includes a butterfly disk operable between an open and closed position. Positioning  410  the butterfly valve assembly within the conduit further includes orienting  420  the shaft within the conduit at an angle offset from an axis of flow at approximately 10 degrees. 
     In the exemplary embodiment, method  400  includes fabricating  430  a plurality of tapered roller bearings using a machining process, such as for example a turning process using a lathe, or alternatively, a stamping process. Method  400  includes maintaining  440  the butterfly disk at a substantially constant axial position using a plurality of tapered roller bearings circumferentially spaced within at least one bearing assembly positioned on an external surface of the conduit. Maintaining  440  the butterfly disk at a substantially constant axial position further includes orienting  450  the plurality of tapered roller bearings at a bearing angle of approximately 20 degrees. 
     Exemplary embodiments of bearing assemblies and valve systems are described in detail above. The above-described bearing assemblies facilitate maintaining an axial and radial position for components of the valve system during operation by including tapered roller bearings within a bearing race and housing. Furthermore, the tapered roller bearing described herein are fabricated from a tempered, stainless steel material that will withstand high temperatures and that will substantially prevent corrosion, and therefore may be used in a broader range of applications. 
     Although the foregoing description contains many specifics, these should not be construed as limiting the scope of the present invention, but merely as providing illustrations of some of the presently preferred embodiments. Similarly, other embodiments of the invention may be devised which do not depart from the spirit or scope of the present invention. Features from different embodiments may be employed in combination. The scope of the invention is, therefore, indicated and limited only by the appended claims and their legal equivalents, rather than by the foregoing description. All additions, deletions and modifications to the invention as disclosed herein which fall within the meaning and scope of the claims are to be embraced thereby. 
     Although the apparatus and methods described herein are described in the context of bearing assemblies for use with anti-ice systems on aircraft, it is understood that the apparatus and methods are not limited to aerospace applications. Likewise, the system components illustrated are not limited to the specific embodiments described herein, but rather, system components can be utilized independently and separately from other components described herein. 
     As used herein, an element or step recited in the singular and proceeded with the word “a” or “an” should be understood as not excluding plural elements or steps, unless such exclusion is explicitly recited. Furthermore, references to “one embodiment” of the present invention are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. 
     This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.