Frame for railway truck

A frame for use with a railway truck may have a pivot housing, a first arm member extending outward from the pivot housing and having opposing distal ends, and a second arm member substantially identical to the first arm member and extending outward from the pivot housing opposite the first arm member. Each of the first and second arm members may have a generally planar upper plate, a generally planar lower plate, and plurality of webs vertically disposed between the generally planar upper and lower plates. An upper surface of the pivot housing may be generally co-planar with the generally planar upper plates of the first and second arm members.

TECHNICAL FIELD

The present disclosure relates generally to a frame and, more particularly, to a frame for a railway truck.

BACKGROUND

Locomotives traditionally include a car body that houses one or more power units of the locomotive. The weight of the car body is supported at either end by trucks that transfer the weight to opposing rails. The trucks typically include cast steel frames that provide a mounting for traction motors, axles, and wheel sets. Locomotives can be equipped with trucks having two, three, or four axles. An example of a four-axle locomotive truck is disclosed in U.S. Pat. No. 4,485,743 that issued to Roush et al. on Dec. 4, 1984.

Each truck frame of a typical locomotive is connected to its corresponding axle by coil springs that act directly on a journal box of each wheel. The journal box transmits vertical loads through the springs to the wheels and provides a housing for axle bearings. Pedestals are attached to the truck frame and hold the truck frame in place relative to the journal box while permitting some vertical movement of the truck frame. The pedestals transfer tractive and transverse loads to the wheels via the journal box. In some applications, an equalizer extends between the journal boxes of different wheels to equalize loads from the truck frame on the wheels. Rounded surfaces at ends of the equalizer typically rest on top of a wear plate attached to the journal box.

Conventional truck frames generally extend a significant distance past the associated axles to accommodate the pedestals described above. Such truck frames are also often multi-level and have interrupted geometry that avoids interference with various components and/or provides force transfer paths between the components. These numerous transitions and interrupted geometry can result in increased structural stress and reduce a durability of the truck frame.

SUMMARY

In one aspect, the present disclosure is related to a frame for a railway truck. The frame may include a pivot housing, a first arm member extending outward from the pivot housing and having opposing distal ends, and a second arm member substantially identical to the first arm member and extending outward from the pivot housing opposite the first arm member. Each of the first and second arm members may include a generally planar upper plate, a generally planar lower plate, and plurality of webs vertically disposed between the generally planar upper and lower plates. An upper surface of the pivot housing may be generally co-planar with the generally planar upper plates of the first and second arm members.

In another aspect, the present disclosure may be related to another frame for a railway truck. The frame may include a pivot housing, a first arm member extending outward from the pivot housing and having opposing distal ends, and a second arm member substantially identical to the first arm member and extending outward from the pivot housing opposite the first arm member. The frame may also include a plurality of brackets connected to the distal ends of the first and second arm members. The plurality of brackets connected to the distal ends of the first arm member may face inward toward the plurality of brackets connected to the distal ends of the second arm member.

DETAILED DESCRIPTION

FIG. 1illustrates an exemplary embodiment of a locomotive10that includes a car body12supported at opposing ends by a plurality of trucks14(e.g., two trucks14). Each truck14may be configured to engage a track16and support a base platform18of car body12. Any number of engines may be mounted to base platform18and configured to drive a plurality of wheels24included within each truck14. In the exemplary embodiment shown inFIG. 1, locomotive10includes a first engine20and a second engine22that are lengthwise aligned on base platform18in a travel direction of locomotive10. One skilled in the art will recognize, however, that first and second engines20,22may be arranged in tandem, transversally, or in any other orientation on base platform18.

Car body12may be fixedly or removably connected to base platform18to substantially enclose first and second engines20,22, while still providing service access to first and second engines20,22. For example, car body12may be welded to base platform18and include one or more access doors23strategically located in the vicinity of first and second engines20,22. Alternatively, car body12may be attached to base platform18by way of fasteners such that portions or all of car body12may be completely removed from base platform18to provide the necessary access to first and second engines20,22. It is contemplated that car body12may alternatively be connected to base platform18in another manner, if desired.

Base platform18may be configured to pivot somewhat relative to trucks14during travel of locomotive10along a curving trajectory of tracks16. As shown inFIG. 2, base platform18may be provided with a pivot shaft25at each end (only one end shown inFIG. 2) that extends downward from a transverse center to engage a bearing26within a bolster assembly28. Bolster assembly28may include a generally flat beam (also known as a span bolster)30that is rigidly or flexibly connected to bearing26and extends in a lengthwise direction of base platform18. Additional pivot shafts32may extend downward from opposing ends of span bolster30away from car body12to engage pivot housings34within separate bogies36of each truck14, thereby pivotally linking bogies36together and to car body12. In this configuration, car body12and bogies36may all pivot independently relative to bolster assembly28, allowing locomotive10to follow a curving trajectory of tracks16. Pivot shaft25may be designed to transmit tractive forces (i.e., forces in a fore/aft direction, including propelling and braking forces) and lateral (i.e., side-to-side) forces between car body12and span bolster30, with minimal transmission of vertical forces (i.e., weight of locomotive10). Similarly, pivot shafts32may be designed to transmit these same tractive and lateral forces between span bolster30and bogies36, with minimal transmission of vertical forces.

Span bolster30may be spaced apart from base platform18by way of a plurality of resilient members (e.g., springs)38located in pairs in general fore/aft alignment with pivot shafts32at the sides of base platform18. In particular, bolster assembly28may include transverse arms40located at the ends of span bolster30and rigidly connected to pivot shafts32. Springs38may be sandwiched between distal tips42of arms40and an underside of base platform18. In the disclosed embodiment, springs38may include rubber compression pads that are removably connected to arms40of span bolster30and pinned to base platform18, although other configurations of springs38may also be utilized. Springs38may be configured to undergo a shearing motion during pivoting of base platform18relative to span bolster30. One or more limiters43may be rigidly connected to the underside of base platform18and configured to vertically retain span bolster30in location relative to base platform18and/or to limit a maximum amount of relative pivoting between base platform18and bolster assembly28(i.e., to limit a maximum shearing of springs38). Springs38may be configured to transmit vertical forces between car body12and span bolster30, with minimal transmission of tractive or lateral forces.

Span bolster30may be similarly spaced apart from bogies36by way of additional resilient members (e.g., springs)44located in pairs in general fore/aft alignment with pivot housings34at the sides of bogies36. In particular, springs44may be removably connected to a frame46of each bogie36and pinned to an underside of span bolster30(e.g., to an underside of arms40) in the same manner that springs38are connected to arms40and pinned to car body12. Similar to springs38, springs44may be rubber compression pads that are configured to undergo a shearing motion during lateral displacement (i.e., pivoting) of bogies36relative to span bolster30. In this configuration, springs44may be configured to transmit vertical forces between bogies36and span bolster30, with minimal transmission of tractive or lateral forces.

Springs44may be located immediately below springs38to reduce stresses induced within span bolster30by vertical forces. In particular, vertical forces from frame46may pass through springs44and then through springs38into base platform18, with reduced transmission of forces in transverse directions through span bolster30. This configuration may help reduce distortion of span bolster30due to vertical force transmission.

An exemplary embodiment of one bogie36of truck14is shown inFIG. 3. It should be noted, however, that all bogies36within locomotive10may be substantially identical. Each bogie36may be an assembly of components that together transfers lateral, tractive, and vertical forces between tracks16and car body12. For example, each bogie36may include, among other things, wheels24, a plurality of axles48connected between opposing wheels24, frame46, and an equalizer50located at each side of bogie36to connect wheels24with frame46and to help distribute vertical loads between axles48.

Two wheels24may be rigidly connected at the opposing ends of each axle48such that wheels24and axles48all rotate together. A traction motor51, for example an electric motor driven with power generated by first and second engines20,22(referring toFIG. 1), may be disposed at a lengthwise center of each axle48, connected to frame46via pivot housing34, and configured to drive wheels24via axles48. The opposing ends of axles48may be held within separate bearing assemblies52such that forces (i.e., lateral, tractive, and vertical forces) may be transferred from wheels24through axles48and bearing assemblies52to the remaining components of bogie36.

FIG. 4illustrates an exemplary embodiment of frame46. As can be seen in this figure, frame46may be a fabrication of multiple components, including pivot housing34and substantially identical left and right arm members54that extend from pivot housing34in the lengthwise direction of bogie36to form a general H-shape. In this embodiment, pivot housing34may be an integral cast component having a center opening that is lined with a low-wear material, for example nylon, that is configured to receive pivot shaft32of bolster assembly28(referring toFIG. 2). Each of arm members54may be joined to opposing ends of pivot housing34by way of welding or mechanical fastening, as desired.

Arm members54may each include a generally planar top plate56, a generally planar bottom plate58, and a plurality of generally planar webs60that extend vertically between top and bottom plates56,58. Top plate56, bottom plate58, and webs60may be welded together to form a hollow enclosure that provides the required strength to bogie36, while maintaining a low assembly weight. When arm members54are connected to pivot housing34, top plates56of each arm member54may be generally co-planar with each other and with an upper surface of pivot housing34. Likewise, bottom plates58of each arm member54may be generally co-planar with each other and with a lower surface of pivot housing34. This flat, layered profile of frame46may help reduce packaging difficulties, help reduce part numbers and cost, and help increase a strength of bogie36.

An end bracket61having a wear pad62(e.g., a nylon pad) oriented inward toward pivot housing34may be located at distal ends of each arm member54. As shown inFIG. 4, each of the plurality of brackets61includes a first base plate with a rear face attached transversely to each forwardly facing end face of the distal ends of the first and second end members, and a second base plate on the first base plate and extending outward from the forwardly facing end face of the first base plate along a longitudinal direction of the first and second arm members. Wear pad62may be removably connected to machined surfaces of end bracket61and configured to engage bearing assembly52to laterally constrain bogie36and vertically limit movement of bogie36relative to wheels24, as will be described in more detail below.

A notched bracket64may be formed at a lower side of each arm member54, in general fore/aft alignment with pivot housing34. Notched bracket64may be formed within a fabricated or cast component that is fixedly connected to bottom plate58, for example by way of welding. Notched bracket64, as will be described in more detail below, may be configured to transfer tractive forces between frame46and equalizer50.

It is contemplated that frame46may include additional features associated with auxiliary components, if desired. For example, frame46could include one or more brackets and/or mounting plates configured to receive braking components, to accommodate motors51(shown as integral with pivot housing34), to hang conduits or wiring, to support cooling ducts, etc. Although some of these additional features may be depicted inFIG. 4, these features will not be described in detail in this disclosure.

As shown inFIG. 5, equalizer50may be an assembly of components that together facilitate the transfer of forces between bearing assemblies52and frame46. In particular, equalizer50may include, among other things, an outer plate66and a substantially identical inner plate68that are held apart from each other by one or more spacers70and clamped together by one or more rivets72or other fasteners. Each of outer and inner plates66,68may be generally planar and fabricated as a single piece from flat stock in a general U-shape (seen inFIG. 2). The absence of welding between outer and inner plates66,68of equalizer50may permit the use of high-strength materials that typically are inconvenient to weld. Opposing ends of equalizer50may rest atop front- and rear-located bearing assemblies52at a side of bogie36, with a wear pad configuration74located between equalizer50and bearing assemblies52. In this manner, vertical forces may be transferred between equalizer50and bearing assemblies52via wear pad configurations74.

Equalizer50may be pinned to axles48by way of bearing assemblies52to transfer tractive forces between wheels24and equalizer50. In particular, a pin76may be disposed between inner and outer plates66,68at opposing ends thereof, and held in place by one of rivets72. Pin76may be received within a rubber bushing78that is mounted within bearing assemblies52, thereby constraining equalizer50relative to wheels24in the tractive direction, yet still allowing bearing assemblies52some ability to roll and yaw with respect to equalizer50. Wear pad configurations74may further allow this relative rolling motion to occur through deflection when wheels24encounter irregularities in track16.

Tractive forces may be transferred between equalizer50and frame46by way of a link80. Link80may be positioned between outer and inner plates66,68at a general lengthwise mid-portion, and pivotally held in place at a first end82by one of rivets72. Link80may be pivotally connected at an opposing second end84to frame46. In particular, a pin86may pass through second end84of link80and be clamped within notched bracket64by way of one or more vertically-oriented fasteners (not shown). When frame46and equalizer50are in equilibrium (i.e., not moving significantly relative to each other), link80may be generally horizontal. However, during relative movement between frame46and equalizer50, link80may pivot in the vertical direction somewhat. In this configuration, link80may constrain frame46relative to equalizer50in the tractive direction, yet still allow some relative movement in the vertical direction through pivoting of link80. In some embodiments, a rubber bushing (not shown) may be located within first and/or second ends82,84to receive rivet72and/or pin86, if desired. The rubber bushing may allow for some roll and/or yaw of frame46relative to equalizer50.

One or more spring supports88may also be disposed transversely between outer and inner plates66,68at a lower portion of equalizer50to facilitate vertical dampening of frame movement relative to equalizer50. Spring supports88may embody plates that are held in a generally horizontal position by rivets72, each support88being configured to receive a corresponding spring90. Springs90may be sandwiched between equalizer50and an underside of frame46(i.e., between spring supports88and bottom plate58). In this configuration, vertical forces may be transferred between frame46and equalizer50by way of springs90.

Frame46may be laterally constrained and vertically limited relative to equalizer50by way of end brackets61located at the distal ends of arm members54. In particular, end brackets61may be configured to engage an external surface of bearing assemblies52, with wear pads62positioned therebetween. With end brackets61engaging bearing assemblies52on opposing sides of bogie36, frame46may be constrained from transversely moving left or right relative to wheels24. In addition, each of end brackets61may be located vertically between the portion of bearing assembly52that supports offset rubber bushing78at a lower side, and one of rivets72at an upper side. In this manner, excessive vertical movement of frame46may cause end brackets61to engage bearing assembly52and/or the rivet72, thereby limiting further vertical movement of frame46.

As shown inFIG. 6, each bearing assembly52may include multiple components that cooperate to connect the associated equalizer50to a corresponding axle48(referring toFIG. 5). In particular, bearing assembly52may include, among other things, a housing92having a generally flat top that vertically supports ends of equalizer50via wear pad configuration74, and a bottom portion forming a partial bore94configured to receive axle48and an offset bore96configured to receive rubber bushing78. An additional wear pad97may be vertically mounted to housing92just above offset bore96and configured to mate against end brackets61of frame46(i.e., against wear pads62of frame arms54). A cap98may engage housing92opposite the flat top to close off partial bore94and retain axle48. Offset bore96may be offset inwardly relative to equalizer50, such that equalizer50may be located between partial bores94of tandem bearing assemblies52. A first bearing (not shown), for example a tapered roller bearing may be disposed within partial bore94and configured to support vertical and transverse loading of axle48. Rubber bushing78may function as a second bearing disposed within offset bore96to receive pin76and support tractive and transverse loading of equalizer50, while still allowing pivoting of pin76to accommodate roll and yaw differences between wheels24and equalizer50. Housing92and cap98may be cast or fabricated components, as desired. Cap98may be joined to housing92by way of one or more vertically-oriented fasteners (not shown).

Wear pad configuration74may be a subassembly of components that together cushion relative movements between equalizer50and axles48(i.e., via bearing assembly52). In particular, wear pad configuration74may include, among other things, a base plate100formed in a general U-shape and extending downward over the flat top of housing92to engage the front and back of housing92. Sides of base plate100may include holes102configured to receive fasteners (not shown) that retain wear pad configuration74in place relative to housing92. A compressed rubber pad104may be bonded to an upper surface of base plate100, and an upper plate106may be bonded to a side of rubber pad104opposite base plate100. In this configuration, an end of equalizer50(i.e., ends of outer and inner plates66,68) may rest on and be supported by upper plate106, and wear pad104may shear and/or compress to allow relative movement between base and upper plates100,106. In one embodiment, the spacers70located between the ends of outer and inner plates66,68of equalizer50(shown only inFIG. 5) may be welded or otherwise fixedly connected to upper plate106, if desired. A motion limiter108may be mounted at an outside end of housing92, relative to equalizer50, and configured to limit motion of equalizer50in the vertical direction during extension of wear pad104that occurs during lifting of the truck assembly.

INDUSTRIAL APPLICABILITY

The disclosed railway truck may provide a means for transferring tractive, transverse, and vertical forces between the wheels and the car body of a locomotive with reduced wear of components. This reduction of component wear may help to extend the useful life of the locomotive as well as reducing service costs. The transfer of forces between wheels24and car body12, as well as servicing requirements of locomotive10will now be described.

During operation of locomotive10, motors51may be powered by engines20,22to exert torque on wheels24via axles48, thereby driving wheels24to propel locomotive10. Reactionary forces associated with the forward or reverse motion of wheels24may be transferred from axles48to equalizers50by way of bearing assemblies52, rubber bushings78, and rivets72that hold rubber bushings78. Equalizers50, having received these tractive forces from axles48at both ends, may transfer these forces to frame46via rivets72associated with links80, pins86, and notched bracket64located with each arm member54of frame46. From arm members54, the tractive forces may move inward through pivot housing34to pivot shaft32within bolster assembly28, and from pivot shaft32through span bolster30and center bearing26to pivot shaft25. These tractive forces may then move from pivot shaft25through base platform18to car body12. Reactionary tractive forces may then travel in reverse direction through these same components back to wheels24.

As locomotive10travels along tracks16, transverse irregularities in tracks16and/or a curving trajectory of tracks16may exert transverse forces on wheels24. These transverse forces may travel from wheels24through axles48and bearing assemblies52to arm members54of frame46by way of wear pad97attached to housing92and wear pads62connected to end brackets61of arm members54. The path used to transfer transverse forces from frame46to car body12may be the same path taken by tractive forces described above. Reactionary transverse forces may then travel in reverse direction through these same components back to wheels24.

Car body12and all components between car body12and wheels24may exert vertical forces on wheels24that can change based on vertical irregularities and/or vertical trajectory changes of tracks16. Wheels24may support these vertical forces by way of axles48, bearing assemblies52, equalizers50, frame46, and springs44,38. In particular, wheels24may transfer vertical forces with bearing assemblies52via axles48. Equalizers50, resting atop bearing assemblies52, may transfer the vertical forces therewith via wear pad configurations74. The vertical forces may be transferred between equalizers50and arm members54of frame46via spring supports88and springs90. Frames46may transfer vertical forces with bolster assembly28via springs44, while bolster assembly28transfers vertical forces with base platform18and car body12via springs38.

During the transfers of forces described above, the different components of locomotive10may move relative to each other. For example, the ends of equalizers50may rock (i.e., yaw and roll) somewhat relative to the tops of bearing assembly52due to the bushing/pin connection therebetween. Similarly, frame46may move fore/aft and/or side-to-side somewhat relative to equalizers50due to the pin/link connection therebetween. Similarly, frame46of each bogie36may pivot relative to span bolster30, while span bolster30may pivot relative to base platform18and car body12.

All of the motion described above may cause wear that can be accommodated via easily replaceable components. For example, wear pad configurations74located between the ends of equalizers50and bearing assembly52may be periodically replaced at a relatively low cost to help avoid metal-to-metal contact therebetween, which would normally result in very expensive re-machining in conventional systems. Similarly, wear pads62located between end brackets61and wear pads97of housing92, may be periodically replaced to help avoid metal-to-metal contact therebetween. Springs38and44may likewise be periodically replaced to help maintain desired spacing and vertical bias between frames46and bolster assembly28and between bolster assembly28and base platform18.

It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed railway truck without departing from the scope of the disclosure. Other embodiments of the railway truck will be apparent to those skilled in the art from consideration of the specification and practice of the railway truck disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope of the disclosure being indicated by the following claims and their equivalents.