Patent Publication Number: US-8991318-B2

Title: Stabilized railway freight car truck

Description:
BACKGROUND OF THE INVENTION 
     The traditional three piece railway freight truck consists of one bolster and two side frames that are configured to utilize friction shoes between the bolster and side frames as a means to provide damping of the suspension. The friction shoes additionally provide a limited means to keep the relationship of the side frames aligned squarely to the bolster and wheelsets. Lateral track displacement irregularities are transmitted to the wheelsets and into the side frames creating uneven lateral displacement of the side frames. The uneven displacement of the side frames exceeds the friction shoes&#39; squaring capability, allowing the side frames to pivot or hinge about the friction shoes and bolster. The pivoting or hinging of the side frames yaws the wheelsets, creating misalignment to the railway track, which limits the stability of the traditional three piece freight truck. 
     The present invention relates to a stabilized railway freight car truck with a rigid transom, pivotally affixed between the side frames. The side frames are also pivotally affixed to the wheelsets. The pivotal relationship of the wheelsets to the side frames and the side frames to the transom allows lateral movement, which prevents the lateral track displacement irregularities from being transmitted to the bolster and into the vehicle. The pivotal but rigid connection between the side frames and transom eliminates yawing of the wheelsets thusly making the railway freight truck stable. 
     The stabilized railway freight car truck also has friction damping that initiates at low friction and changes to damping at higher friction once engaged. The damping is derived from friction shoes with a pivotal friction face in the form of friction shoe inserts that allow the friction force to react radially and pivotally. 
     The stabilized railway freight car truck bolster is supported on springs. The springs are supported on the transom which is pivotally supported on the side frames. The friction shoes, located between the bolster and side frames, further decouple lateral track displacement irregularity inputs transmitted to the wheelsets through the side frames by low friction inserts between the friction shoes and bolster. There is a space on either side of the friction shoes and bolster that allows lateral movement. The lateral movement of friction shoes along the space prevents transmission of lateral railway track displacement irregularities from reacting at the bolster and into the vehicle. 
     The stabilized railway freight car truck side frames are longitudinally rigid due to the limited longitudinal space between the transom and the side frames. The longitudinally rigid side frames are connected to the wheelsets by rotating lugs, adapters and elastomeric steering pads. The elastomeric stiffness of the steering pads provides movement to align the wheelsets to the railway track. 
     It is an object of the present invention to provide a railway freight car truck having improved stability and resistance to misalignment with the track. 
     SUMMARY OF THE INVENTION 
     A stabilized railway freight car truck of the three piece design is comprised of two laterally spaced side frames and a laterally extending bolster. A transom extends into an opening in each side frame. The ends of the transom are pivotally supported on transom hearings, which are supported on the lower portion of the center openings of the side frames. The spring suspension is supported on the transom, which in turn supports the holster. 
     For stable performance of the railway freight car truck, it is desirable to utilize friction damping in the form of friction shoes between the bolster and the side frame. There is a bolster low friction insert between friction shoes and bolster, as well as a space on either side of the friction shoes to accommodate lateral movement of the friction shoes without transmitting the lateral movement to the bolster. 
     The damping is derived from friction shoes with a pivotal friction face in the torr of a friction shoe insert that allows the friction force to react radially or pivotal. The damping contact surfaces are the side frame column wear plates and the friction shoe inserts. Preferably both the column wear plate and friction shoe insert are made of hardened material to limit wear. The friction shoe insert is positioned on a low friction insert recessed in the friction shoe face. The friction shoe insert has a radial space around it in the recess of the friction shoe face. The friction shoe insert can move pivotal and radially in the recess until it contacts the friction shoe recess wall. The friction shoe insert once in contact with the recess wall moves at the higher friction between the column wear plates and the friction shoe inserts, resulting in low friction force at initiation and higher friction force once engaged by movement of the suspension. The friction shoe insert also rotates against the column wear plate at low friction. 
     It is also desirable to have translation and warp constraint between the two side frames. The rotating connections of the transom to the side flumes and the side frames to the wheelsets mitigate track input from destabilizing truck performance. The translation or warping of the two side frames is eliminated by utilizing plain bearings between the transom bearing and rigid transom, and plain bearings are used between the side frame to the rotating lugs to eliminate gaps. The rotating lugs retain the elastomeric steering pads and bearing adapters. The rotating lugs keep the steering pads and bearing adapters aligned to the bearings and wheelsets due to the pivotal connection to the side frames. 
     It is also desirable to provide steering by translation at the elastomeric steering pad to control the wheelsets alignment to the railway track. The steering pad elastomer stiffness is sufficient to align the wheelset to the railway track in curves and straight track. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings, 
         FIG. 1  is a perspective view of the truck assembly of a first embodiment of a stabilized railway car truck with components shown in a separated fashion in accordance with the present invention; 
         FIG. 2  is a partial detailed cut away view of the truck assembly of a first embodiment of a stabilized railway car truck in accordance with the present invention; 
         FIG. 3A  is a partial view of a bolster and friction shoe of a first embodiment of a stabilized railway car truck in accordance with the present invention; 
         FIG. 3B  is a section view and a perspective view of the friction shoe of a first embodiment of a stabilized railway car truck in accordance with the present invention; 
         FIG. 4  is a perspective view of the transom relationship to the side frame of a first embodiment of a stabilized railway car truck in accordance with the present invention; 
         FIG. 5  is a perspective partial view of the side frame relationship to the adapter of a first embodiment of a stabilized railway car truck in accordance with the present invention; 
         FIG. 6  is a section view of the pivotal relationship of the transom and side frame of the first embodiment of a stabilized railway car truck in accordance with the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to  FIG. 1 , a stabilized railway truck  1  is seen to be comprised of two laterally spaced side frames  2  and  27 , between which bolster  3  extends. Bolster  3  is seen to include bolster ends  22  and  23 , each of which extends through a side frame opening  24 . One end of bolster  3  and one end of transom  4  will be described. As the identical opposite end is not completely shown in  FIG. 1 . Transom  4  extends laterally under bolster  3 . Transom end  25  supports a spring group  15 . Spring group  15 , is seen to support bolster end  23 . Transom end  25  is supported on transom bearing  10 , which transom bearing  10  is supported on a sideframe support surface  28 A. The radial clearance between transom end  25  and transom bearing  10  is filled by elongated transom support bearing  11 . The transom hearing ends  29  and  30  are supported adjacent side frame lower support  28 . Each of side frames  2  and  27  and bolster  3  are usually a cast steel unitary structure. Transom  4  can be cast of ductile iron or steel. It is possible for transom  4  to be fabricated of steel, but a cast ductile iron transom is preferred due to the weight savings. 
     Bolster  3  is seen to include on its upper surface a bolster center plate  31 , and a pair of laterally spaced side bearings  19 . Each bolster end includes a pair of sloped surfaces  23 A and  23 B. Each bolster end slope surface forms a friction shoe pocket with sideframe. 
     Axles  32  and  33  extend laterally between side frames  2  and  27 . Railway wheels  5  are press fit on the ends of axles  32  and  33 . The ends of axles  32  and  33  are received in roller  245  bearings  34 . Roller bearing  34  supports bearing adapter  6 . 
     Bearing adapter  6  supports elastomeric steering pad  7 . Steering pad  7  supports rotating lug  8 . Rotating lug  8  is pivotally supported at the pedestal jaw end of side frames  27  and  2 . Elongated support bearing  9  is placed between the pedestal jaw end of side frames  2  and  27  and the rotating lug  8 . 
     Referring now to  FIG. 2 , a partial detailed cut away view of the truck assembly  1  is shown along with detailed partial views of bolster  3  and side frame  2  in general cross section. Transom  4  extends laterally between side frames  2  and  27 . Transom end  25  is supported on transom bearing  10 . Transom bearing end  30  is supported and longitudinally constrained by side frame lower support  28 . Friction shoe  14  engages bolster  2  via a low friction insert retainer  16  and a low friction insert  17  fitted on sloped face  14 B of friction shoe  14 . Friction shoe  14  can move laterally across low friction insert  17 . Friction shoe  14  vertical face  14 A also has a low friction insert  13  and friction shoe insert  12  that engages column wear plate  18  attached to vertical column  18 A of side frame  2 . 
     Referring now to  FIG. 3A , presenting a partial view of bolster  3  and friction shoe  14 . Bolster  3  is typically a cast steel unitary device, with internal ribs and supports to provide the strength necessary for a structural component of a stabilized railway freight car truck  1  while providing a generally lower weight structure. Bolster  3  has space  20  on both sides of friction shoe  14 . The space  20  allows lateral movement of friction shoe  14  without transmitting the movement to the bolster  3 . Lateral movement is accomplished due to the low friction insert  17  on friction shoe  14  decoupling the friction shoe force in direction of travel. 
     Referring now to  FIG. 1  and  FIG. 3B , presenting a section view and a perspective view of friction shoe  14 . Friction shoe vertical face  14 A has a recess  35  for the friction shoe low friction insert  13  and the friction shoe high friction insert  12 . The high friction insert  12  extends outwardly beyond the surface of friction shoe front face  14 A. Friction shoe insert  12  has radial space  21  in recess  35  to move or rotate on and in contact with the low friction insert  13 . Once movement of the friction shoe insert  12  exceeds the radial space  21 , meeting the friction shoe vertical face  14 A recess  35  wall, the low friction created by the friction shoe low friction insert  13  changes to the high friction between the high friction insert  12  and side frame column wear plate  18 . Friction shoe sloped face  14 B received bolster low friction insert retainer  16  which iN turn receives bolster low friction insert  17 . Bolster low friction insert  17  is located between bolster sloped face  23 A and sloped face  14 B of friction shoe  14 . 
     Referring now to  FIG. 4 , presenting a perspective view of the relationship of transom  4  to side frame  2 . Side frame  2  pivotally supports transom  4  on transom bearing  10 . Transom bearing ends  29  and  30  have tapered walls  36  that engage in the side frame lower support  28  walls. The radial space between the transom  4  and transom bearing  10  is filled with transom support bearing  11 . This makes the connection between the side frame  2  and transom  4  vertically supported, but able to pivotally rotate. 
     Referring now to  FIG. 5 , a perspective partial view of the relationship of side frame  2  to the bearing adapter assembly  6 A. Side frame  2  pedestals  2 A have conical roofs  2 B to receive support bearings  9  and rotating lugs  8 . Rotating lug  8  allows pivotal movement between side frame  2  and bearing adapter  6 . Rotation of the rotating lug ends  37  is restricted in the lug recess  38  of side frame  2 . Rotating lugs  8  also support elastomeric steering pad  7 . Rotating lug  8  is constrained from longitudinal movement by translation stop  39  contact against the end of conical roof  2 B of the side frame pedestal  2 A. Steering is accomplished by the wheelset longitudinal force on bearing adapter  6  compressing the elastomeric steering pad  7  against the rotating lug ends  37 . 
     Referring now to  FIG. 6 , presenting a sectional view of the pivotal relationship of transom  4  and side frame  2 . The wheelsets  5  support bearing adapter  6 , steering pad  7 , rotating lug  8 , and support hearing  9  that supports side frame  2 . Side frame  2  in turn supports transom bearing  10 , support bearing  11 , and transom  4 . The normal vertical load aligns transom bearing  10  directly below the rotating lug  8  pivot. When a lateral movement is imparted at the bearing adapter  6 , the movement reacts through side frame  2  to transom  4 . The lateral movement mitigates the railway track lateral displacement irregularities from transom  4 .