PASSIVE STEERING FOR A THREE PIECE RAILWAY TRUCK

Abstract

The traditional three piece railway freight truck prevents the wheel sets from achieving radial alignment to curves by the rigid side frames restraining the wheelsets. The side frames also constrain the wheelset from radial aligning to curves by the limited gap between the wheelset bearing and the side frame pedestal jaws. The present invention opens the side frame pedestal jaws to allow the wheel sets to yaw and align radially to curves. The side frame is supported on wheel sets by elastomeric pads and bearing adapters. The present invention utilizes the elastomeric pad stiffness to compress in pitch motion that allow the wheel set to move in an arc forward or backward in the open jaws of the side frame. The elastomeric pad stiffness also allows the wheelset to twist the pads allowing the wheelset to radially align to the curve. The pads elastic stiffness is sufficient to return when the wheelset is align to straight track.

Description

BACKGROUND OF THE INVENTION

The traditional three piece railway freight truck consists of one bolster and two side frames. The bolster which carries the car body extends centrally through the side frames. The bolster is supported by a suspension consisting of springs that support the bolster and friction shoes with springs that create damping on vertical bolster movement. The suspension is centrally located and supported by the side frame. The side frames ends have pedestal jaws that support on and capture the bearing adapters. The bearing adapters are supported on the wheelset axle bearings. The wheel set consists of a live axle with wheels and bearings at the ends.

The truck steering mechanism consists of tapered cone wheel treads. When the truck enters a curve, the rail turns out from under the center of the wheel treads. As the rail moves out from under the center of the wheel tread, the tapered cone changes each wheel's diameter and the circumference of the wheel on the outside of the curve becomes larger and the wheel to the inside of the curve circumference become smaller. The distance the wheels roll down the rail becomes uneven which yaws the wheelset and attempts to radially align the wheel sets to the curve.

The traditional three piece railway freight truck may prevent the wheel sets from achieving radial alignment to curves due to the rigid side frames acting to restrain the wheelsets from aligning with a curve in the rails. The side frames also may constrain the wheelset from radial aligning to curves by the limited gap of 0.144 inches on either side of wheelset axle bearing and the side frame pedestal jaws.

The present invention opens the side frame pedestal jaws to 0.331 inches on either side of wheelset axle bearing and the side frame pedestal jaws to allow the wheel sets to yaw and align radially to curves. The side frame is supported on wheel sets by elastomeric pads and bearing adapters. The present invention utilizes the stiffness of the elastomeric pad to allow the adapters to pitch and twist in the open jaws of the pedestal. The adapter pitch motion is what allows the wheel set to move in an arc forward or backward in the open pedestal jaws of the side frame. The elastomeric pad also allows the wheelset to twist the pads allowing the wheelset to radially align to the curve. The pads elastic stiffness is sufficient to return when the wheelset is align to straight track.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings,

FIG. 1 is a perspective view of a traditional three piece railway freight car truck assembly of a passive steering three piece railway car truck in accordance with a first embodiment of the present invention;

FIG. 2 is a detailed exploded partial view of the relationship the pad and adapter to the side frame and wheel set of the passive steering three piece railway car truck in accordance with a first embodiment of the present invention;

FIG. 3 is a top view of a railway car truck in a curve with the adapters also shown as pitched in separate side views, of the passive steering three piece railway car truck in accordance with a first embodiment of the present invention;

FIGS. 4A-4D are detailed sectional views of a yawed railway car truck wheel set with the relationship between pitch and yaw of the adapter on the elastomeric adapter pad, of the passive steering three piece railway truck in accordance with a first embodiment of the present invention.

FIGS. 5A and 5B are detailed sectional views of a Pitched and twisted adapter compressing the elastomeric adapter pad, of the passive steering three piece railway truck in accordance with a first embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to FIG. 1, is a perspective view of a traditional three piece railway freight car truck assembly 1 is seen to be comprised of two laterally spaced side frames 3 between which bolster 4 laterally extends. Bolster 4 is seen to extend through a central opening in each side frame 3. Suspension 5, usually comprised of a coil spring group, is seen to support the bolster 4. The side frames 7 are supported at the pedestals 14 by adapter pad 6 and adapter 7 setting on axle bearing 8 of the wheelsets 2. The wheelset 2 consists of two wheels 10 pressed onto a journal portion near ends of an axle 9. The wheelset 2 has axle bearings 8 mounted at both ends of axle 9. Adapter pads 6 are typically comprised of a structural elastomer such as Urethane.

Referring now to FIG. 2, is a detailed exploded partial view of the relationship the elastomeric adapter pad 6 and adapter 7 to side frame 3 at the pedestal 14. The adapter 7 is seated on bearing 8. The end of wheel set 2 is shown with wheel 10 on axle 9. The wheel 10 has a tread 16 that is outwardly tapered in a cone shape. Sideframe pedestal opening is formed by depending jaws 12 and pedestal roof 15. The inside surface of jaws 12 may include lugs 13 to help position and hold adapter 7. Elastomeric adapter pad 6 vertically captured between the adapter 7 top surface 26 and the pedestal roof 15. The Legs 27 of the elastomeric adapter pad 6 are laterally captured between the lugs 13 and the adapter 7.

Referring now to FIG. 3, is a top view, with a side views of each pedestal 14 and wheel, of a railway car truck 1 in a curve 11 with the adapters 7 pitched 22 and 23. When the railway car truck 1 enters a curve 11, the rail turns out from under the center of the wheel treads 16. As the rail moves out from under the center of the wheel tread, 16 the tapered cone essentially changes the wheel's diameter with regard to the center axle-rail distance such that the circumference 17 of the wheel on the outside of the curve becomes larger and the wheel to the inside of the curve circumference 18 becomes smaller. The distance the wheels roll down the rail becomes uneven which yaws 19 the wheelset 2 and aligns the wheel sets 2 to the curve 11. The side frame 3 at the pedestals 14 have open jaws 12 to allow the wheel sets 2 yaw 19. The elastomeric adapter pads 6 become unevenly vertically loaded as the wheel set 2 yaws 19 on adapter 7. The uneven vertical loading compresses the elastomeric adapter pad 6 at one end more than the other. This acts to pitch the adapter in 22 for the inside of the curve 11 and pitch the adapter out 23 for the outside of the curve 11.

FIGS. 4A-4D show detailed sections of a yawed wheel set 2 with the relationship between pitch 22 and 23 and twist 24 and 25 of the elastomeric adapter pad 6 on adapter 7. The wheel set 2 supports the adapter 7 and the elastomeric adapter pad 6 on the pedestal roof 15 of the side frame 3. The vertical load on the elastomeric adapter pad 6 is evenly distributed when the wheel set 2 is rolling on straight track. When the wheel set 2 is yawed in curves the vertical load on the elastomeric adapter pad 6 becomes uneven and the adapter pitches 22 and 23. As the adapter pitch as shown at 22 and 23 the adapters also twist on the elastomeric adapter pad 6. The twisted 23 and 24 adapter 7 is constrained by lugs 13 in the top of the open jaws 12. Each adapter 7 and adapter pad 6 is received in one of the sideframe pedestal ends formed by jaws 12. Each adapter pad 6 has a resistance to pitch and twist such that a longitudinal steering force created between the wheels to rails of a wheelset of from 5,000 to 7,000 pounds is sufficient to radially align the wheelset with a curve of up to 10 degrees in a railway track. Further, jaws 12 are open enough to allow such deformation of the adapter pads 6 to allow the wheel set to yaw to align with the curve in the railway track. The pedestal jaws 12 are opened 0.331 inches on either side of the bearing to allow space for the adapter 7 to pitch and twist against adapter pad 6. The open jaws 12 is sufficient for wheelset 2 to radial align to a 10 degrees in the railway track curve.

FIGS. 5A and 5B show detailed sectional views of a Pitched 23 and twisted 25 adapter 7 compressing the elastomeric adapter pad 6. The yawed wheelset bearing 8 creates longitudinal force about the bearing 8. The longitudinal force creates a moment about the top surface 26 of adapter 7. The longitudinal force and displacement of bearing 8 cause the adapter 7 to compress the elastomeric adapter pad 6 unevenly in the direction of the displacement. The uneven vertical displacement of the elastomeric adapter pad 6 pitches the adapter 7 and bearing 8. Bearing 8 is also yawing as it is displaced. The adapter 7 sitting on bearing 8 is forced to accommodate the yawing motion. Adapter 7 twist 25 the elastomeric adapter pad 6 and compress the elastomeric adapter pad 6 legs 27 against lugs 13 to allow the yawing motion.

Claims

1. A railway car truck comprising

a bolster and two parallel sideframes,

the bolster having two ends each received in an opening in one of the sideframes,

a spring group supporting the bolster end in each sideframe,

each sideframe having two pedestal ends,

two axles each having two ends,

two wheels each fitted to a journal portion of each axle,

a plurality of axle bearings each fitted on one of the axle ends,

a plurality of adapters each with an adapter pad, with each adapter and adapter pad received in one of the sideframe pedestal ends,

wherein each adapter pad has a resistance to pitch and twist such that a longitudinal steering force created between the wheels to rails of a wheelset of from 5,000 to 7,000 pounds is sufficient to radially align the wheelset with a curve in a railway track.

2. The railway cart truck of claim 1 wherein

the sideframe pedestal end is comprised of longitudinally spaced jaws that allow the adapter pad to deform to allow the wheel set to yaw to align with the curve in the railway track.

3. The railway car truck of claim 2 wherein

the adapter pad will deform enough to allow the wheel set to yaw to align with a curve of up to 10 degrees in the railway track curve.

4. A railway car truck comprising

a bolster and two parallel sideframes,

the bolster having two ends each received in an opening in one of the sideframes,

a spring group supporting the bolster end in each sideframe,

each sideframe having two pedestal ends,

two axles each having two ends and two journal portions,

a wheel fitted to a journal portion of each axle,

a plurality of axle bearings each fitted on one of the axle ends,

a plurality of adapters each with an elastomeric adapter pad, with each adapter and

elastomeric adapter pad received in one of the sideframe pedestal ends,

wherein each adapter pad has a resistance to pitch and twist such that a longitudinal steering force created between the wheels to rails of a wheelset of from 5,000 to 7,000 pounds is sufficient to radially align the wheelset with a curve in a railway track.

5. The railway cart truck of claim 4 wherein

the sideframe pedestal end is comprised of longitudinally spaced jaws that allow the adapter pad to deform to allow the wheel set to yaw to align with the curve in the railway track.

6. The railway car truck of claim 5 wherein

the adapter pad will deform enough to allow the wheel set to yaw to align with a curve of up to 10 degrees in the railway track.

7. The railway cart truck of claim 4 wherein

the sideframe pedestal jaws that are opened 0.331 inches on either side of the bearing to allow the adapter pad to deform to allow the wheel set to yaw to align with the curve in the railway track.