GB2401845A

GB2401845A - Rail vehicle truck arrangement

Info

Publication number: GB2401845A
Application number: GB0411004A
Authority: GB
Inventors: Paul Hewitt
Original assignee: Powell Duffryn Rail Ltd
Current assignee: Powell Duffryn Rail Ltd
Priority date: 2003-05-23
Filing date: 2004-05-18
Publication date: 2004-11-24
Also published as: GB0411004D0; EP1479585A1; GB0311867D0

Abstract

The truck arrangement comprises a wheelset 38 carrying a saddle member 35, a resiliently deformable rocker member 42,44 being interposed between the saddle member 35 and the wheelset 38, the rocker member 42, 44 being resiliently deformable to damp lateral accelerations of the wheelset 38 relative to the saddle member 35. The rocker member 42, 44 comprises a rubber or rubber-like material layer 48 with a plate 46 secured to a roof 76 of the saddle member 35, and a rocker adaptor member 42 secured to the material layer 48 via a plate 50 bonded to the material.

Description

Railcar Truck The present invention is directed to a railcar truck, for

example a railcar truck having a side frame pedestal including a wear plate adapted to be engaged by a friction wedge and a saddle having a rocker member. However the invention may be used with other types of truck.

One design of a railway truck includes a pair of spaced apart generally parallel side frames connected by a transverse bolster. Each side frame includes a pedestal at each end thereof that is adapted to be connected by a saddle to a wheel set. A plurality of springs extend between the saddle and the side frame such that the side frame is resiliently supported on the saddle. Friction wedges are disposed between the saddle and the side frame to dampen vertical, lateral and longitudinal movement of the side frame with respect to the saddle. Arrangements of this type are sometimes known as axle motion or unitruck arrangements.

The saddle is typically designed to define a cavity within which a rocker member is mounted, the rocker member being designed to co-operate with the bearing of the axle of the wheel set so as to allow a degree of articulation between the axle and the saddle. The rocker member typically comprises a metallic, for example steel, component which is rigidly bolted or otherwise secured to the saddle to allow for replacement of the rocker member in the event that it becomes damaged or worn.

According to the invention there is provided a truck arrangement comprising a wheelset carrying a saddle member, a resiliently deformable rocker member being interposed between the saddle member and the wheelset, the rocker member being resiliently deformable to damp lateral accelerations of the wheelset relative to the saddle member.

The resiliently deformable rocker member conveniently comprises a rubber like material component secured to an adapter member which, in turn, cooperates with the wheelset or a bearing associated therewith to allow the adaptor member to move relative to the saddle. The rocker member is conveniently releasably secured to the saddle member, for example using bolts, to allow replacement thereof.

The invention will further be described, by way of example, with reference to the accompanying drawing, Figure 1, which is a view, partly in section, illustrating part of a truck in accordance with an embodiment of the invention.

The railcar truck 20 shown in Figure 1 includes a pair of spaced apart and generally parallel side frames 22 (only part of one of which is shown) . The side frames 22 are connected to one another by a transverse bolster (not shown). Each side frame 22 includes a pedestal 24 at each end. The pedestal 24 includes a first pedestal jaw 26 and a second pedestal jaw (not shown). A pedestal cavity 30 is l formed between me first and second pedestal jaws 26. The first pedestal jaw 26 includes an inclined face 32 and the second pedestal includes a corresponding inclined face.

A saddle 35 is adapted to be located within the pedestal cavity 30. A plurality of resilient coil springs 36 extend between the saddle 35 and the pedestal 24 such that the pedestal 24 is resiliently supported by the springs 36. A bearing and an axle 38 of a wheel set is coupled to the saddle 35 such that the axle 38 is rotatable with respect to the saddle 35. A plurality of friction wedges 39 having wear surfaces formed of, for example, composite material and steel or acicular iron, are resiliently biassed by one or more of the springs 36 into engagement with the pedestal 24 and the saddle 35 to dampen vertical and lateral movement of the pedestal 24 with respect to the saddle 35.

A wear member 40 is removably attached to the inside surface the inclined face 32 of the first pedestal jaw 26 and another wear member is also attached to the 1 S inside surface ofthe inclined face ofthe second pedestal jaw. The wear member 40 is preferably formed from, for example, cast iron which has a kinetic coefficient of friction with steel or acicular iron of approximately 0.15.

Forming the wear plate from cast iron which has a kinetic coefficient of friction with the steel or acicular iron of the friction wedge 39 of approximately 0. 15, as opposed to forming the wear plate from steel which has a kinetic coefficient of friction with the steel or acicular iron of the friction wedge 39 of approximately 0.30, promotes generation of lower axle centering force. Axle centering forces act horizontally toward the centre ofthe axle at ewes in the railroad back end originate from wheel/rail frictional forces which result in surface forces between the friction wedge 39 and the wear member 40. When the axle centering force can be decreased, the forces generated at the wheel/rail interface that are needed to move the axle are also lower and self-steering of the wheel is promoted. Lower self steering forces are particularly required at laden. High resistance to self-steering can be caused by use of steel wear plates. In addition, a cast iron wear plate has a better damping capacity than a steel wear plate, making the suspension less prone to generating noise.

The saddle 35 ofthe railcartruckincludes a centre post 74 having a generally horizontal roof 76, a first side wall 78 that extends downwardly from the roof 76, and a second side wall 82 that extends downwardly from the roof 76. The second side wall 82 is spaced apart from the first side wall 78 and a cavity 86 is formed therebetween. A horizontal first shelf 88 extends outwardly from the bottom end of the first side wall 78 to one end of the saddle 35, a second shelf extends outwardly from the bottom end of the second side wall to a second end of the saddle 35. Each shelf 88 is adapted to engage and support the bottom end of the springs 36.

The saddle 35 is supported on the bearing and axle 38 by a rocker adaptor member 42 which is secured to a resiliently deformable component 44. As illustrated, the component 44 comprises a mounting plate 46 to which a layer 48 of S a rubber or rubber-like resiliently deformable material is bonded. A second mounting plate 50 is bonded to the layer 48. The component 44 is secured to the roof 76 of the saddle 35 and to the rocker adaptor member 42 by means of bolts 52 (only those securing the component 44 to the saddle 35 being shown), but other securing means could be used if desired. The use of bolts 52 allows replacement of the component 44 and/or adaptor member 42, for example in the event of damage or wear thereto. Further, shims can be introduced to allow height adjustment, for example to compensate for wear of the wheelset.

The inherent flexibility of the component 44 allows the rocker adaptor member to tilt relative to the saddle in the plane perpendicular and at right angles to the axial plane of the wheelset, thereby allowing resilient damping of lateral accelerations of the wheelset, as well as permitting limited vertical or lateral damping movement ofthe adaptor member. The permitted angle oftilt between the rocker adaptor member and the saddle relative to the axial plane ofthe wheelset can be as much as approximately 10 . Conveniently, lateral stops (not shown) are provided in or on the pedestal and/or the saddle to limit such tilting movement.

It will be appreciated that a number of modifications to the arrangement describing hereinbefore may be made within the scope of the invention. l

Claims

1. A truck arrangement comprising a wheelset carrying a saddle member, a resiliently deformable rocker member being interposed between the saddle member and the wheelset, the rocker member being resiliently deformable to damp lateral accelerations of the wheelset relative to the saddle member.

2. An arrangement according to Claim 1, wherein the resiliently deformable rocker member comprises a rubber or rubber-like material component secured to an adaptor member which, in turn, co-operates with the wheelset or a bearing associated therewith to allow the adaptor member to move relative to the saddle 1 0 member.

3. An arrangement according to Claim 2, wherein the rocker member allows the adaptor member to tilt relative to the saddle member.

4. An arrangement according to Claim 3, wherein the rocker member allows the adapter member to tilt through an angle of approximately 10 relative to the saddle 1 5 member.

5. An arrangement according to Claim 3 or Claim 4, further comprising stops adapted to limit such tilting movement.

6. An arrangement according to any of Claims 2 to 5, wherein rocker member permits limited damping of vertical movement ofthe adapter member relative to the saddle member.

7. An arrangement according to any one of Claims 2 to 6, wherein the rubber like material component is bonded to mounting plates.

8. An arrangement according to any one of Claims 2 to 7, wherein the rocker member is releasably securable to the saddle member.

9. An arrangement substantially as hereinbefore described with reference to the accompanying drawings.