Abstract:
A gear has a central ring positioned about an axis, opposing tabs that extend from a first axial side of the central ring, and a shouldered ring that extends from a second axial side of the central ring, the shouldered ring having a lip that extends radially inward toward the axis.

Description:
FIELD OF THE INVENTION 
     The subject matter disclosed herein relates to aircraft power systems, and in particular to a deaerator shaft and gear for use within an IDG. 
     BACKGROUND 
     in a conventional integrated drive generator (IDG) system, an input shaft connectable to a gearbox driven by an aircraft engine is connected to a mechanical differential, the differential having an output connected to drive a generator. A variable speed transmission, such as a hydromechanical transmission, is associated with the mechanical differential and controlled to modify the output of the differential, as required, whereby the input speed to the generator remains constant even though the speed of the input shaft may vary. 
     Such systems require oil and, accordingly, IDG&#39;s may include a deaerator system to separate oil from an air/oil mixture. Deaerator systems may include a centrifuge device mounted to a rotating shaft that separates the oil from the air/oil mixture. The centrifuge mounted to a shaft will make up the deaerator. In addition, the deaerator could be used to mount other rotating components such as a gear or Permanent Magnet Generator (PMG). 
     BRIEF DESCRIPTION OF THE INVENTION 
     In one aspect, a gear comprises a central ring positioned along an axis, opposing tabs that extend from a first axial side of the central ring; a shouldered ring that extends from a second axial side of the central ring, the shouldered ring having a lip that extends radially inward toward the axis. 
     In another aspect, a method of replacing gears comprises removing a first gear from a shaft; placing a second gear on the shaft, the second gear comprising a central ring positioned about an axis; opposing tabs that extend from a first axial side of the central ring; a shouldered ring that extends from a second axial side of the central ring, the shouldered ring having a lip that extends radially inward toward the axis. 
     In another aspect, a method of replacing gears comprises removing a first gear from a protruding ring on a shaft; placing a second gear on the protruding ring of the shaft, the second gear comprises a central ring positioned about an axis; opposing tabs that extend from a first axial side of the central ring; a shouldered ring that extends from a second axial side of the central ring, the shouldered ring having a lip that extends radially inward toward the axis. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The subject matter which is regarded as the invention is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which: 
         FIG. 1  is an illustration of an deaerator assembly and a pump assembly within a housing of an IDG in accordance with one embodiment of the invention. 
         FIG. 2  is an illustration of an deaerator shaft in accordance with one embodiment of the invention. 
         FIG. 3  is an illustration of an intake end of the deaerator shaft in accordance with one embodiment of the invention. 
         FIG. 4  is an illustration of a discharge end of the deaerator shaft in accordance with one embodiment of the invention. 
         FIG. 5  illustrates a cross-sectional view of a central segment of the deaerator shaft in accordance with one embodiment of the invention. 
         FIG. 6  illustrates a cross-sectional view of a tubular discharge segment. 
         FIG. 7  is an isometric view of a gear with opposing tabs in accordance with a second embodiment of the invention. 
         FIG. 8  illustrates a cross-sectional view of the gear in accordance with the second embodiment of the invention. 
         FIG. 9  illustrates an axial view of the gear in accordance with the second embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  illustrates a view of a deaerator shaft  102  and pump assembly  104  within an integrated drive generator (IDG) housing  106  in accordance with one embodiment of the invention. The IDG may include the deaerator shaft  102 , a deaerator drive gear  108 , the pump assembly  104 , and pump drive gear  109 . In operation, the pump assembly  104  is driven the pump drive gear  109 . The pump drive gear  109  may be mated with a deaerator drive gear  108  surrounding the deaerator shaft  102 . As the pump drive gear  109  turns, the deaerator shaft  102  may rotate. Fluid flowing into the deaerator shaft  102  may be centrifuged, causing a supply of oil to be transferred and siphoned by the pump assembly  104 . In operation, a sufficient amount of oil is processed and flows through the deaerator shaft  102  so that the pump assembly  104  (in particular a charge pump component of the pump assembly) may be provided with a full supply of oil. A sufficient amount of oil may be supplied to components of the IDG for cooling and lubrication purposes by the charge pump component. 
       FIG. 2  illustrates the deaerator shaft  102  in more detail. The deaerator shaft  102  comprises a plurality of tubular segments that may extend axially along an axis  202 . The axis  202  may extend the length of the deaerator shaft  102 . 
     A tubular intake segment  204  is disposed along the axis  202 , forming an intake end  206  of the deaerator shaft  102 . The tubular intake segment  204  is configured to receive fluid and has a diameter of approximately 1.175 in. (2.9845 cm). The tubular intake segment  204  has a length of approximately 0.684 in. (1.737 cm) extending along the axis  202 . The end of the tubular intake segment  206  that forms the intake end  206  is chamfered in one embodiment. The chamfered edge can form a 45 degree angle with respect to an outer wall of the tubular intake segment  204 . 
     The deaerator shaft  102  further comprises a tubular sleeve attachment segment  208  that is adjacent to the tubular intake segment  204 . The tubular sleeve attachment segment  208  extends along the axis  202  and has a diameter that is greater than the diameter of the tubular intake segment. In one embodiment, the diameter of the tubular sleeve attachment segment  208  is approximately 1.195 in. (3.0353 cm). The tubular sleeve attachment segment  208  has a length of approximately 0.684 in. (1.737 cm) extending along the axis  202 . 
     The deaerator shaft  102  further comprises a central segment  210  extending along the axis  202 . The central segment  210  may be adjacent to the tubular sleeve attachment segment  208 , and located on an opposite side of the tubular sleeve attachment segment  208  from the tubular intake segment  204 . A protruding ring  212  extends radially from the central segment  210  about a circumference of the central segment  210 . The protruding ring  212  divides the central segment  210 , forming a shortened central segment portion  214  and a lengthened central segment portion  215 . The protruding ring  212  may have opposing flat surfaces  216  on an outer radial surface of the protruding ring  212 . 
     In one embodiment, the shortened central segment portion  214  and lengthened central segment portion  215  measure 0.347 in. (0.881 cm) and 0.69 in. (1.75 cm) along the axis  202 , respectively. The diameters of the shortened central segment portion  214  and the diameter of the lengthened central segment portion  215  may be 1.3215 in. (3.355 cm). The protruding ring  212  may measure 0.584 in. (1.483 cm) along the axis  202  in one embodiment. 
     The deaerator shaft  102  may further comprise a tubular discharge segment  218  extending along the axis  202 , forming a discharge end  219  of the deaerator shaft  102 . The tubular discharge segment  218  may be adjacent to the shortened central segment portion  214 . The tubular discharge segment  218  has a diameter of approximately 1.175 in. (2.984 cm), which is approximately equal to the diameter of the tubular intake segment  204 . 
     The tubular discharge segment  218  may comprise a plurality of openings  220 . The plurality of openings  220  is disposed about a circumference of the tubular discharge segment  218 . The plurality of openings  220  may be spaced equally around a circumference of the tubular discharge segment  218 . Each opening extends in an axial direction for approximately 0.88 in. (2.2352 cm) along the axis  202 . As described in more detail below, the plurality of openings  220  can act as a primary discharge point for fluid flowing through the deaerator shaft  102 . The discharge end  219  may act as a secondary discharge point for fluid, and the tubular discharge segment  218  may be chamfered at the discharge end  218 . 
       FIGS. 3 and 4  illustrate a rotated view of the deaerator shaft  102 . A plurality of vanes  302  may extend from a radial center of the deaerator shaft  102  to an interior wall  303  of the deaerator shaft  102 . The plurality of vanes  302  may extend axially along a length of the deaerator shaft  102 , forming channels within the interior of the deaerator shaft  102 . The channels may assist with accelerating the fluid from longitudinal flow to rotating flow as the deaerator shaft  102  rotates, and as the fluid travels from the intake end  206  to the discharge end  219 . Each channel may terminate at a respective opening of the plurality of openings  220 . In one embodiment, three vanes extend from a radial center of the deaerator shaft  102 , forming three channels of equal capacity. Each vane terminates at the inner wall at a point  120  degrees apart from an adjacent vane. 
     The plurality of vanes  302  may be axially recessed within the tubular intake segment  206  and the tubular discharge segment  219 . Accordingly, the plurality of vanes  302  may not extend the entire length of the deaerator shaft  102 . As shown in  FIG. 3 , the intake edges  304  of the plurality of vanes  302  are recessed with respect to the intake end  206  of the deaerator shaft  102 . The distance from the intake edges  304  of the plurality of vanes  302  to the intake end  206  may be 0.125 in. (0.318 cm), in one embodiment. 
     In  FIG. 4 , the plurality of vanes  302  are axially recessed relative to the discharge end  219  of the deaerator shaft  102 . In particular, discharge edges  402  of the plurality of vanes  302  are recessed with respect to the discharge end  219  of the deaerator shaft  102 . The length of the recess between the discharge end  219  and the discharge edges  402  can vary, but in one embodiment the length of the recess is 0.376 in. (0.955 cm). Furthermore, the discharge edges  402  may be cupped, with a central part of the plurality of vanes  302  further recessed with respect to the discharge edges  402 . 
       FIG. 5  illustrates a cross-sectional view of the central segment  212 . Each vane of the plurality of vanes  302  may form a rounded surface  502  with the inner radial wall of the central segment  212 . The rounded surface  502  may promote ease of manufacture of the vanes. The diameter of the protruding ring  212  as measured between outer radial walls of the protruding ring  212  may be 1.562 in. (3.967 cm) in one embodiment. The distance between opposing flat surfaces  504 ,  506  of the protruding ring  212  may be approximately 1.374 in. (3.48 cm). The opposing flat surfaces  504 ,  506  may run parallel to one another. 
       FIG. 6  illustrates a cross-sectional view of the tubular discharge segment  218 . The configuration of the plurality of vanes  302  extending through the tubular discharge segment  218  is illustrated in more detail. In particular, the plurality of vanes  302  is cupped, forming a central discharge opening  602  between fins  604  of the plurality of vanes  302 . The central discharge opening  602  may extend 1.183 in. (3.005 cm) from the discharge end  219 , and radially 0.4 in. (1.016 cm). The plurality of vanes  302  may be recessed 0.376 in. (0.955 cm) from the discharge end. Accordingly, each fin  604  of the plurality of vanes  302  may extend 0.807 in. (2.05 cm) along the axis  202 . Although an edge  606  of the fin  604  is squared in  FIG. 6 , the edge  606  of each fin  604  may have a rounded edge. 
     Referring to  FIG. 7  with continuing reference to  FIGS. 2 and 5 , an isometric view of a gear  700  is shown in accordance with the subject invention. The gear  700  is ring-shaped with opposing tabs  702 ,  704  that extend axially from an inner side  706  of the gear  700 . As described in more detail below, the opposing tabs  702 ,  704  are configured to lock with the opposing flat surfaces (not shown) of the protruding ring (not shown). The opposing tabs  702 ,  704  are used to provide a positive transfer of torque from the gear  700  to the deaerator shaft. The gear  700  is axially mounted on protruding ring  212 . The opposing tabs  702 ,  704  drive on opposing flat surfaces  504 ,  506  of the deaerator shaft, transmitting torque to the deaerator shaft. 
       FIG. 8  illustrates a cross-sectional view of the gear  700 . The gear  700  is disposed along an axis  802 . The gear  700  has a central ring  804  with a diameter of approximately 1.3254 in. (3.366 cm) between inner radial walls of the central ring  804 . The gear  700  has a plurality of teeth  806  circumferentially disposed about an outer radial surface of the central ring  804 . The plurality of teeth  806  extend along the axial length of the central ring  804 . The plurality of teeth  806  provide a thrust surface by which a mating gear (not shown) may transmit torque to gear  700 . In one embodiment, the central ring  804  and the plurality of teeth  806  have an axial length of 0.35 in. (0.889 cm). 
     The gear  700  has a shouldered ring  808  with a diameter between inner radial surface  810  of the shouldered ring  808  of 1.195 in. (3.035 cm), and a diameter between outer radial surface  814  of the shouldered ring  808  of 1.513 in. (3.843 cm). The shouldered ring  808  may extend axially from the central ring  804  for a distance of 0.84 in. (2.133 cm). The shouldered ring  808  also provides a thrust surface when mounted to the deaerator shaft and helps to axially locate the deaerator shaft within the IDG. 
     The opposing tabs  702 ,  704  of gear  700  extend in a direction opposite to the shouldered ring  808 . The opposing tabs  702 ,  704  may extend 0.2 in. (0.508 cm) in an axial direction. 
       FIG. 9  illustrates an axial view of the gear  700 . The opposing tabs  702 ,  704  have a length of 0.35 in. (0.889 cm) extending along the cross-sectional axis  802 . Radially-inward facing surfaces  806 ,  807  of the opposing tabs  702 ,  704  are flat. However, the radially-outward facing surfaces  808 ,  810  of the opposing tabs  702 ,  704  may be arced, similar to the circumference of the central ring  804 . 
     While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.