AU2005248978B2

AU2005248978B2 - A railway bogie

Info

Publication number: AU2005248978B2
Application number: AU2005248978A
Authority: AU
Inventors: Douglas Gordon Cummings
Original assignee: Bradken Resources Pty Ltd
Current assignee: Bradken Resources Pty Ltd
Priority date: 2001-02-01
Filing date: 2005-12-30
Publication date: 2009-03-26
Anticipated expiration: 2022-02-01
Also published as: AU2005248978A1

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Applicant(s): BRADKEN RESOURCES PTY LIMITED A.C.N. 098 300 988 Invention Title: A RAILWAY BOGIE The following statement is a full description of this invention, including the best method of performing it known to me/us: 2 A RAILWAY BOGIE

INO

s FIELD OF THE INVENTION The present invention relates generally to a railway bogie 00 and relates particularly to a side frame of a railway bogie.

00 BACKGROUND TO THE INVENTION S 10 A conventional three piece railway freight bogie includes a pair of side frames spaced apart by a bolster on which Cl railway decking or the like is mounted. Each of the side frames includes an upper elongate compression member having pedestal legs at each of its ends. Opposing pedestal legs of adjacent side frames provide support for an axle/wheel set.

The railway bogies are designed to certain axle loadings, rail gauge and track clearances for example 15 to 40 tonne per axle. Heavier axle loaded bogies in particular experience cracking or other failure associated with fatigue. This fatigue results from stress concentration in general but other areas can and are affected specifically the inner pedestal legs of the side frames. Traditionally, the pedestal legs have been engineered to include additional material in the regions of stress concentration.

Irrespective many designs are still susceptible to failure.

SUMMARY OF THE INVENTION According to the present invention there is provided a side frame of a railway bogie, the side frame comprising: a pair of pedestal legs, each located at a respective opposite end of the member.

Typically the side frame is of a type having a pair of lower diagonal elongate tension members each at one end being connected adjacent a respective end of the upper compression member; lower elongate member at opposing ends being 3 Q)connected to an opposite end of respective of the pair of ;4lower diagonal tension members; It has been found that, somewhat contrary to conventional teachings, by reducing the amount of material at the upper wall of the pedestal leg (eg by forming an opening) the 00 centroid of the pedestal cross-section can be lowered, which h can also reduce stress in a lower wall of the leg.

00 S 10 In one embodiment, the opening is shaped ellipsoidal. In another embodiment, the opening is "running-track" shaped eg oval with parallel sides and curved ends.

Preferably the opening is generally positioned above said elongate and longitudinally extending internal stiffening rib disposed within the upper compression member at each of the pedestal legs.

The effect of lowering the centroid and reducing stress in the lower wall of the leg by including an opening can be further enhanced by the inclusion of the stiffening rib.

Sis disposed between said upper and lower walls.

Preferably the stiffening rib is one of a pair of laterally separated stiffening ribs. More preferably the pair of stiffening ribs diverge laterally from the lower to the upper wall of the pedestal leg. It is understood 00 that the pair of divergent ribs serve to distribute and reduce stress in the pedestal leg.

00 (1 10 Preferably the pair of stiffening ribs each include an Saperture formed by core links being adapted to support a central core used in casting of the pedestal leg. More preferably the apertures of the ribs are aligned to "tie" the central core whilst casting the pedestal leg.

Typically each of the pedestal legs defines a pedestal jaw being adapted to seat a bearing. More typically the bearing is dedicated to an axle of the railway bogie.

BRIEF DESCRIPTION OF THE DRAWINGS In order to achieve a better understanding of the nature of the present invention a preferred embodiment of a side frame of a railway bogie will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a side elevational view of a pedestal leg of a side frame of a railway bogie; Figure 2 is a sectional view taken through 2-2 of Figure 1; Figure 3 is a plan view together with an enlarged detail view of the pedestal leg of Figure 1; Figure 4 is a sectional view of part of an alternative pedestal leg of a side frame of a railway bogie; Figure 5 is a sectional view of another embodiment of a pedestal leg; and Figure 6 is a sectional view of a further embodiment of a pedestal leg.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS I The following embodiments of the invention are designed to be incorporated in a conventional railway bogie (not shown). The bogie includes a pair of trapezium-shaped side frames spaced apart and interconnected by a bolster.

The bolster is elongate and at opposing ends is sprung 00 seated within the respective side frames. The side frames each include an upper elongate compression member, a pair 00 of lower diagonal elongate tension members, and lower C 10 elongate member. The upper compression member at opposing Sends includes a pair of respective pedestal legs which each define downwardly facing pedestal jaws. Opposing jaws of opposing side frames provide mounting for respective bearings in which an axle/wheel set is rotationally mounted. The various members of the side frames are cast hollow and include upper and lower walls together with opposing side walls cast integrally with one another.

Figures 1 and 2 best illustrate one embodiment of the invention incorporated in a side frame of a railway bogie such as that described in the preceding paragraph. These figures depict enlarged elevational and sectional views of a pedestal leg 10 and pedestal jaw 12 of the side frames.

The pedestal jaw 12 is adapted to receive a bearing to which one of the axle/wheel sets is rotationally mounted.

The pedestal leg 10 is cast hollow using conventional foundry techniques and as shown in Figure 2 includes an upper and a lower wall 14 and 16 together with an opposing pair of side walls 18 and The pedestal leg 10 is susceptible to cracking or other failure at an innermost corner or high stress zone designated generally as 22 of the inner pedestal jaw 12.

This is in particular a problem with high (typically tonne and above) axle load bogies under conditions of fatigue and vibration. Importantly, this embodiment of the invention incorporates a pair of stiffening ribs 24 and 26 cast internally of the pedestal leg 10 at the high CI stress zone 22. The pair of internal stiffening ribs 24 and 26 are laterally spaced apart and extend longitudinally through part or all of the pedestal leg The ribs 24 and 26 are cast integral with the lower wall 16 and diverge laterally or splay to connect with the 00 upper wall 14. This orientation of the stiffening ribs 24 and 26 distributes and reduces the stress at the high 00 stress zone 22. The ribs 24 and 26 lower the centroid of C 10 the pedestal leg 10 and effectively reduce the stress in Sthe lower wall 16 of the leg In some embodiments the upper wall of the pedestal leg includes an opening designated as 28 and best shown in Figure 3. The opening 28 is shaped ellipsoidal and by reducing material at the upper wall 14 of the pedestal leg lowers the centroid of the pedestal leg 10. This together with the stiffening ribs 24 and 26 reduces the stress concentration in the pedestal leg 10 and in particular in the high stress zone 22.

In a conventional railway bogie without either the stiffening ribs or the opening in the upper wall, loadings of up to 260 MPa have been experienced in the inner corner of the pedestal leg at the critical stress zone 22. These stresses for the conventional bogie were present at axle loadings of 36 tonne. The applicant has conducted Finite Element Analysis (FEA) and determined that a maximum stress of about 240 MPa is experienced at the high stress zone 22 of the pedestal leg 10 incorporating the splayed stiffening ribs 24 and 26 under axle loads of 40 tonne.

This indicates a significant drop in stress even with greater axle loading.

The stiffening ribs 24 and 26 are cast within the pedestal leg 10 with increased radii between the ribs 24 and 26 and the upper and lower walls 14 and 16. This is designed to minimise stress concentration at these regions of the Scasting. Additionally, the lower wall 16 and/or side C walls 18 and 20 may be thickened in the region adjacent Sthe high stress zone 22 so as to reduce stress Sconcentration but without raising the centroid.

The splayed stiffening ribs 24 and 26 include a pair of 00 aligned and respective apertures 30 and 32. The apertures and 32 are incorporated for the purpose of tying a 00 central core (not shown) either side of which the C 10 stiffening ribs 24 and 26 are cast. The core links (not Sdepicted) connect to the main core used to cast the hollow pedestal leg Figures 4 to 6 illustrate other embodiments of the pedestal leg shown generally as 100 of a side frame of a railway bogie. For ease of reference and in order to avoid repetition, like components of the pedestal legs and 100 have been designated with an additional "zero", for example the stiffening ribs 240 and 260. Otherwise the sectional views are taken at line 2-2 of Figure 1.

Figure 4 shows a pair of stiffening ribs 240 and 260 laterally spaced and arranged generally parallel to one another. In this example the upper wall 140 of the pedestal leg 100 does not include an opening such as 28.

The alternative embodiments of Figures 5 and 6 incorporate a single stiffening rib 240. The stiffening rib 240 of Figure 5 is located centrally between the opposing side walls 180 and 200 and extends vertically between the upper and lower walls 140 and 160. The pedestal leg 100 does not include the opening such as 28 in the upper wall 140.

The stiffening rib 240 of Figure 6 is also located midway between the side walls 180 and 200 but in this case terminates approximately midway between the upper and lower walls 140 and 160. The stiffening rib 240 is cast continuous with the lower wall 160 and includes additional material built up from the lower wall 160. The upper wall 140 of the pedestal leg 100 of Figure 6 includes an opening 280 in its upper wall 140 similar in shape and I location to that of the embodiment of Figures 1 to 3. The opening 280 is designed to reduce material from the upper wall 140 of the pedestal leg 100 and thus lowers the centroid of the pedestal leg 100.

00 Now that several preferred embodiments of the present invention have been described in some detail it will be OO apparent to those skilled in the art that the side frame CI 10 of the railway bogie has at least the following Sadvantages: 1. the side frame incorporating the stiffening rib and/or opening in the upper wall reduces stress concentration in the high stress zones of the pedestal jaw; 2. the stiffening rib(s) and/or opening in the upper wall of the pedestal leg can be cast in the side frame using existing foundry techniques; and 3. the modified side frame increases the service life of railway bogies particularly under conditions of fatigue and vibration at relatively high axle loadings.

Those skilled in the art will appreciate that the invention described herein is susceptible to variations and modifications other than those specifically described.

For example, it is possible that a reduction in stress concentration may be achieved with an opening in the upper wall alone without the incorporation of stiffening ribs.

The stiffening ribs and/or opening in the upper wall may vary in configuration from that described provided the centroid of the pedestal leg is lowered and thus stresses reduced in the pedestal leg.

All such variations and modifications are to be considered within the scope of the present invention the nature of which is to be determined from the foregoing description.

Claims

1. A side frame of a railway bogie, the side frame N comprising: an upper elongate compression member including two pedestal legs forming a jaw for mounting a wheel axle in a 00 bearing with a jaw located at a respective opposite ends of 1 the member; 00 an elongate and longitudinally extending internal S 10 stiffening rib disposed within the upper compression member adjacent each pedestal jaw, CI wherein said pedestal jaws each have an upper wall including an opening for lowering a centroid of the pedestal leg, and located generally above and adjacent the internal stiffening rib.

2. A side frame as defined in claim 1 wherein the opening is shaped ellipsoidal.

3. A side frame as defined in claim 1 wherein the opening is oval with parallel sides and curved ends.

4. A side frame as defined in any one of the preceding claims wherein each pedestal leg is cast hollow to define the upper wall and a lower wall and wherein the internal stiffening rib is disposed between said upper and lower walls.

A side frame as defined in any one of the preceding claims wherein the stiffening rib is shaped and dimensional to lower a centroid of the pedestal leg and arranged to reduce stress in the lower wall of the leg.

6. A side frame as defined in any one of the preceding claims wherein the stiffening rib is in the form 10 Q)of two laterally separated stiffening elements each of rib- ;like form.

7. A side frame as defined in claim 6 wherein the \O stiffening rib elements diverge laterally from one another in a direction from the lower to the upper wall of the 00 pedestal leg. 00

8. A side frame as defined in either of claims 6 or 7 S 10 wherein the stiffening rib elements each include an aperture Sformed by core links being adapted to support a central core l used in casting of the pedestal leg.

9. A side frame as defined in claim 8 wherein the apertures in the rib elements are aligned to "tie" the central core whilst casting the pedestal leg.

A side frame as defined in any one of the preceding claims wherein each pair of the pedestal legs defines a pedestal jaw being adapted to seat a bearing.

11. A side frame as defined in claim 10 wherein the pedestal jaw is adapted also to mount an axle of a railway bogie in the bearing.

12. A side frame as defined in any one of the preceding claims wherein the side frame further comprises: a pair of lower elongate tension members each at one end being connected adjacent a respective end of the upper compression member; and another lower elongate member at opposing ends being connected to an opposite end of respective of the pair of lower tension members;

13. A side frame of a railway bogie substantially as herein described with reference to Figs. 1-3 or as modified 0 substantially as shown in any one of Figures 4, 5 or 6 of the accompanying drawings.

14. A railway bogie having side frames as claimed in any one of the preceding claims. 00 00 ^l- oq