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' 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.
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.
In the drawings,
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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 23A and 23B. 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.
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