GB2034651A - Railway truck - Google Patents

Abstract

Steering of the wheel axles is through yokes 11, 12 connected to the wheel axles 17 and pivotable in yaw. This truck assembly is characterized by a split pivotal connection in combination with a base plate 22 arranged to provide a space to centrally and conveniently mount a drive motor 39 while still providing the desired steering of the yokes and wheel axles and articulations between the yokes 11, 12, base plate 22, and side frames 20. <IMAGE>

Description

SPECIFICATION Railway truck assembly This invention relates to a railway truck assembly more particularly of the type adapted for steering of the wheel axles radially to the curves along a railway track.

The ability for a railway truck to negotiate relatively sharp curves with a minimum of wear and noise has been provided by steering the wheel axles always radially to the curve. A railway truck assem bly of the above type is described in U.S. Patent No.

3,789,770 in the name of Harold List and in the copending U.S. patent application No. 890,318 by G.

Sobolewski, now U.S. Patent No.

In the latter there is defined a railway truck with wheelsets or wheel axles steered radially of the railway track by a pair of yokes connected to the wheel axles and pivoted to the truck framing and to each other to produce a yaw movement symmetrical about the transverse center line of the truck. In the aforementioned copending patent application, there is provided a central pivot connection which is not providing the required space to centrally mount a rotary motor to drive the truck.

It is a general object of the present invention to provide a railway truck asembly of the above type with a mechanical connection between the yokes adapted to provide space to centrally mount a single drive motor for both axles of the truck while providing the aforementioned steering action of the wheel axles and symmetrical yaw movement of the yokes about the transverse center line of the truck.

It is another object of the present invention to provide good accessibility for servicing and removal of the motor and other components of the drive train in a railway truck assembly of the above type.

In accordance with the present invention there is provided a railway truck assembly comprising a pair of side frames carried at opposite ends of a pair of wheel axles and extending between the axles longitudinally of a railway car body, the axles being steeringly pivotable relative to the frames; a pair of steering yokes rotatively holding the wheel axles, each yoke including a pair of longitudinal projections spaced apart transversely of the railway car body; a base unit pivoted on each of said steering yokes over the respective wheel axles to permit steering of the axles relative to the base, a linkage mechanism pivotally connected to the base unit and operatively connected between the railway car body and one of said steering yokes for steering the latter and the wheel axles relative to the railway car body; and a pair of pivotal couplings yieldably connecting the corresponding longitudinal projections of there spective steering yokes to one another intermediate the wheel axles, the couplings permitting relative roll and pitch displacement between the corresponding projections and relative yaw or steering displacement between the yokes.

By way of example only a preferred embodiment of the invention will now be described with reference to the accompanying drawings; in which; Figure 1 is a side elevation view of a railway car provided with a pair of railway trucks according to the present invention; Figure 2 is a side elevation view of a railway truck assembly according to the present invention; Figure 3 is a top plan view of the railway truck assembly as seen along lines 3 - 3 in Figure 2; Figures 4 and 5 are longitudinal and transverse cross-sectional views as seen along lines 4-4 and 5-5 respectively in Figure 3; and Figure 6 is an enlarged detail view of a resilient coupling joining the adjoining ends of the longitudinal projections of the yoke on each side of the truck.

The railway truck 1 according to the present invention, as shown in Figure 1, is used to carry an end of a car body 2 of any desired construction. The railway truck 1 forms part of a railway truck assembly also comprising a bolster 3 and the associated elements to supportthe car body.

The bolster 3 includes a central portion 4 of tubular construction having a cross section, approximately as shown in Figures 4 and 5. Each end of the bolster 3 includes a base plate portion 5. Each base plate portion 5 is provided with a pair of side plates 6 upwardly extending edgewise along the opposite sides thereof. Each pair of adjacent side plates 6 cooperatively form with the corresponding base plate portion 5 a recess for an air spring unit 7. The latter may be of any appropriate and known construction currently used in the art. The two air springs 7 of each bolster 3 are fixed to the railway car body 2, such as by bolts 8 and carry the load of the corresponding end of the car body. The two side plates 6 on the inboard side of the bolster 3 are connected to the car body 2 by means of a pair of bolster drag links or rods 9.More specifically, each bolster drag link or rod 9 has one end pivoted to the corresponding side plate 6 of the bolster and the other end pivotally connected to a bracket 10 fixedly secured to and downwardly projecting from the bottom of the railway car body. The opposite ends of each bolster drag link 9 are angularly displaceable to accommodate the vertical springing movement between the car body and the bolster and to accommodate the small transverse displacement of the car body relative to the bolster.

The railway truck assembly further includes outboard and inboard yokes 11 and 12 respectively. The outboard yoke 11 includes a main frame 13 while the inboard yoke 12 includes a main frame 14. Each main frame 13 and 14 includes a pair of laterally spaced apart longitudinal projections 15, 15 or 16,16.

Each yoke 11 and 12 is provided with a pair of journal housing to rotatably retain a wheel axle 17 having a flanged wheel 18 on each of the two opposite outer ends thereof. Thus, the flanged wheels 18 are adapted to carry the yokes and the remainder of the railway truck assembly rollably on rails 19.

A pair of side frames 20,20 are positioned on the opposite sides respectively of the railway truck and longitudinally extend parallel one to the other. Each side frame has its inboard end pivoted on the corresponding journal housing 45 of the inboard axle by means of a resilient pad, not shown. Each side frame has its outboard end supported by a sliding pad, not shown, mounted to the journal housing 45 of the outboard axle. Each end of the bolster 3 rests on a sliding pad 21 at the center of the corresponding side frame. Thus, the load of the railway car 2 is transmitted directly through the springs 7, and the bolster 3 onto the sliding pads 21 at the center of the side frames 20,20. The aforementioned sliding pads allow relative longitudinal displacement between the bolster 3 and the side frame 20 when there is truck swivel in a curve.Such displacement occurs in a curve upon angular displacement of the car body 2 and bolster 3. As will be explained later, the angular displacement of the truck relative to the car body assists with steering the yokes 11, 12 to align the wheel axles 17 radially to the curve. Such steering displacement of the yokes also results in relative sliding between the yokes and the side frames 20, 20 on the sliding pads above the outboard axle.

A base plate 22 is positioned under the bolster 3 and overlies the steering yokes 11 and 12. The latter have their outer ends rigidly secured to the corresponding pair ofjournal housings 45 and carried through the latter by the axles 17. The base plate 22 in plan view has the general configuration of the numeral 8 and opposite ends pivoted on the yokes respectively, each by a vertical pivot connection including the pivot 24. The base plate defines a central transverse portion 25.

A lateral stabilizing link or rod 26 extends laterally of the truck between the bolster 3 and the central transverse portion 25 and is pivotally connected to the center of the latter and to the bolster by vertical pivot connections 27 and 28 respectively.

A drag link 29 extends longitudinally of the truck, is pivoted at the inward end to a bracket 30 rigidly secured to and depending from the car body 2, and is pivoted near its other end by the vertical pivot 27 to the base plate 22. A steering link 31 extends transversely of the truck and is pivoted at one end on the outward end of the drag link 29 and at the other end to one end projection 15 of the yoke 11. The yokes 11 and 12 are stabilized and supported in the pitch direction by a vertical link 32 which is pivotally connected at the upper end to a lug 33 projecting from the base plate, and at the lower end to a corresponding longitudinal projection 15 or 16 of the corresponding yoke 11 or 12.The base plate 22 is stabilized against roll motion by a vertical link 34 which is pivotally connected to a lateral lug 35 of the base plate and a bracket 36 secured to the adjacent side frame 20.

As best shown in Figure 6, on each side of the truck the adjoining ends of the longitudinal projections 15 and 16 are yieldably interconnected by a resilient coupling to allow pivoting of the yokes 11 and 12forsteering ofthewheel axles 17, 17. Each such resilient coupling includes a pair of resilient pads 37,37 secured against the opposite sides of the projection 16 at the end thereof and inside forked end 38 of the corresponding projection 15. The pads 37,37 are made of elastomeric material, such as rubber, to provide resilience and produce a higher stiffness rate in lateral direction to aid steering and a lower stiffness rate in the vertical and longitudinal direction to allow roll and yaw motions of the axles.

These resilient couplings in combination with the connections to the plate 23 produce a pivotal connection between the yokes 11 and 12 so that the wheel axles 17, 17 can move radially of a curve along a railway track.

A rotary electric motor 39 is secured by brackets or lugs 40 against the bottom side of the base plate 22 in the space provided between the laterally spaced apart longitudinal projections 15,15 and 16,16 of the yokes. The shafts 41 of the motor 39 extend longitudinally of the truck and are connected at the outer ends to gearboxes 23 arranged to drive the axles 17, 17 of the truck. The gearboxes are held against rotation about the axle by a torque reaction link 42 connected between each gearbox 23 and the corres pondingyoke 11 or 12.

A disk brake 43 is mounted on each wheel axle 17 such that the brake reaction torque on the brake calipers 44 will be transmitted directly to the yokes through links 32 and to the base plate 22.

The operation of the railway truck assembly will now be explained. When the railway car is in a curve, the body 2 thereof will be at an angle relative to the longitudinal axis of the railway truck 1. Since the bolster 3 is restrained relative to the car body, it also makes the same angle relative to the truck 1.

Assuming the dimensions are as shown in the reference patents, the drag link 29 laterally displaces the steering crossbar or link 31 sufficiently with respect to the truck center line to pivot both yokes 11 and 12 in opposite directions such that both wheel axles 17 will take a radial alignment relative to the curve. This pivotal movement is transmitted from yoke 11 to yoke 12 through the resilient pads 37 of the resilient couplings. It must be noted that during such pivoting, the base plate 22 remains aligned with the longitudinal axis of the truck and therefore so does the rotary motor 39. Since in practice the yaw angular displacements of the yokes are very small, the vertical links 32 and 34 effectively remain vertical.

Claims (9)

1. A railway truck assembly comprising a pair of side frames carried at opposite ends of a pair of wheel axles and extending between the axles longitudinally of a railway car body, the axles being steeringly pivotable relative to the frames; a pair of steering yokes rotatively holding the wheel axles, each yoke including a pair of longitudinal projections spaced apart transversely of the railway car body; a base unit pivoted on each of said steering yokes over the respective wheel axles to permit steering of the axles relative to the base; a linkage mechanism pivotally connected to the base unit and operatively connected between the railway car body and one of said steering yokes for steering the latter and the wheel axles relative to the railway car body; and a pair of pivotal couplings yieldably connecting the corresponding longitudinal projections of the respective steering yokes to one another intermediate the wheel axles, the couplings permitting relative roll and pitch displacement between the correspond ing projections and relative yaw or steering displacement between the yokes.

2. A railway truck assembly as defined in Claim 1, wherein a motor is mountable on the base unit in a central space formed between the longitudinal projections of the steering yokes.

3. A railway truck assembly as defined in Claim 1 or Claim 2 wherein said pivotal couplings cooperatively form a split pivotal connection for said steering yokes.

4. A railway truck assembly as defined in Claim 3, wherein each of said pivotal couplings has a higher stiffness rate in the steering yaw direction and a lower stiffness rate in the roll and pitch directions.

5. A railway truck assembly as defined in Claim 1, wherein a pair of vertical pivot connections connect the opposite ends of said base unit centrally of the respective wheel axles and one vertical support is connected to the base unit and to one of the said side frames laterally of the longitudinal axis of the railway car body extending through the said vertical pivot connections, the vertical support operatively supporting the base unit transversely of the longitudinal axis.

6. A railway truck assembly as defined in Claim 5, wherein a vertical support is connected to at least one ofthe steering yokes and to the base unit, and a brake isconnected to the or each steering yoke in longitudinal alignment with the or each vertical support thereby transmitting the brake torque directly to the base unit through the respective steering yoke and its vertical support.

7. A railway truck assembly as defined in any one of the preceding claims, wherein said linkage mechanism includes: a drag link pivotally connected to the railway car body at one end and pivotally connected to the base unit centrally of the wheel axles; and a steering link extending transversely of the railway car body and having opposite ends pivotally connected respectively to the drag link and to one of the steering yokes.

8. A railway truck assembly as defined in Claim 7 as dependent on Claim 2 wherein the pivotal couplings each include a pair of resilient pads secured against the opposite sides of one longitudinal projection of one yoke and inside the forked end formed by a corresponding longitudinal projection of the other yoke, said resilient pads having a higher stiffnes rate in the steering yaw direction and a lower stiffness rate in the roll and pitch directions, and wherein a bolster longitudinally extends transverse iy of the railway car body, a pair of bolster drag links operatively connect the opposite ends of the bolster to the railway car body to prevent a relative yawing motion, a pair of spring suspensions are positioned on the opposite ends of the bolster and the opposite ends of the bolster operatively rest on said side frame respectively intermediate the opposite ends thereof thereby transmitting the load of the car through said bolster and side frames to the wheel axles, and a lateral link longitudinally extends tranversely of the car body and is pivotally connected at one end to said bolster and at the other end to said base unit.

9. A railway truck assembly according to Claim 1 and substantially as herein described with reference to the accompanying drawings.