Side beams of bogie frames for railway vehicles

Abstract

To provide a side beam of a bogie frame for a railway vehicle, which can reduce its weight. [Solution] The side beams (20) are formed of separate structural members including an elongated center plate (21) extending longitudinally between first and second ends thereof, with the center plate's thickness direction parallel to the lateral direction, and first and second suspension mounting portions (22) configured to mount wheelset suspension elements thereto. The first and second suspension mounting portions are cantilevered from the first and second ends of the center plate, respectively, and each suspension mounting portion extends upwardly and longitudinally away from its respective junction with the center plate's end to define a space below the suspension mounting portion for joining a suspension element to a respective wheelset. At each junction, each suspension mounting portion has a lateral width greater than the thickness of the center plate such that the suspension mounting portion protrudes laterally outward from the center plate.

Description

Technical Field

[0001] The present invention relates to side beams of a bogie frame for a railway vehicle.

Background Art

[0002] Due to the increasing social and political demands for decarbonization, lightweight structures have always been a concern in transport structures. Although railway vehicles already offer significant environmental advantages compared to other vehicle transport means, reducing the structural weight remains an important issue. To reduce the weight of railway vehicles, bogie frames made of lightweight welded aluminum alloys have been proposed. However, from the viewpoints of strength, reliability, and maintainability, there is still room for improvement in the welded joints of such frames.

[0003] The bogie frame has structural components for transmitting various loads between the car body of the railway vehicle supported by the frame and the axles held by the frame. In addition to such structural components, the bogie frame usually also provides mounting positions for equipment used in train running, such as motors, suspension items, bearings, brake units, etc. Such equipment occupies space, and there is also room for improvement in how such space is provided around the bogie frame.

[0004] The present invention has been devised in light of the above considerations.

Summary of the Invention

Means for Solving the Problems

[0005] According to a first aspect of the present invention, side beams of a bogie frame of a railway vehicle are provided, two such side beams define respective lateral sides of the bogie frame with respect to the longitudinal direction of the railway vehicle, cross beams extend in the lateral direction of the railway vehicle to join the side beams, and the bogie frame is configured to hold front and rear axles in use. The side beams are individual structural members, An elongated central plate extending between its first and second ends in the longitudinal direction between the positions occupied by the wheelset during use, wherein the thickness direction of the central plate is parallel to the transverse direction, A first and second suspension mounting section configured for attaching axle suspension elements, wherein the first and second suspension mounting sections are cantilevered from the first and second ends of the central plate, respectively, and each suspension mounting section extends upward and longitudinally away from its respective joint with the end of the central plate so as to define the space below the suspension mounting section for joining suspension elements to the respective axles, and at each joint, each suspension mounting section has a width laterally greater than the thickness of the central plate so as to protrude laterally outward from the central plate, It is formed from individual structural members, Individual structural members are joined together by their respective bolt connections.

[0006] Using bolted connections for side beams offers several advantages compared to welded joints, for example. For instance, bolted joints avoid exposing the side beam to residual stresses that can occur with welded joints, and also avoid the potential for a heat-affected zone adjacent to welds in aluminum alloys. Furthermore, bolted connections can be easily installed, repaired, or replaced, especially when they are located in an accessible position on the outside of the bogie frame. Therefore, the reliability and repairability of the side beams can be improved.

[0007] In addition, by extending the suspension mounting portion laterally relative to the central plate at the joint, the side beam of the present invention can provide an additional space outside the central plate and longitudinally bounded by the suspension mounting portion at the end of the plate. This space can be used to accommodate additional components and modules, such as devices related to the operation of railway vehicles. For example, the space can accommodate yaw dampers and / or anti-rolling systems. Conventionally, these devices are mounted outside the bogie frame, increasing the lateral width of the bogie. However, by housing the devices in the additional space, the bogie frame using the side beam of the present invention can be made narrower.

[0008] Each bolted connection can transmit substantially all loads between the individual structural members of the side beam. In this way, these bolted connections can reduce or completely eliminate the need for other connection methods between individual structural members, such as welded connections.

[0009] Structural members can be formed from aluminum alloys. Such alloys enable lightweight structures with good mechanical properties.

[0010] Preferably, the central plate of the side beam is formed from a wrought aluminum alloy. For example, the central plate may be formed by forging, extrusion, or other methods. The central plate may then be subjected to further processing, such as machining, to achieve the final shape. Advantageously, wrought aluminum alloys generally have superior strength and toughness compared to cast alloys, which allows for a reduction in the thickness of the central plate while maintaining its mechanical properties.

[0011] In contrast, the suspension mounting portion is preferably formed from a cast aluminum alloy. For example, the suspension mounting portion may be sand-cast, die-cast, continuous-cast, pressure-cast, or one-shot-cast. The suspension mounting portion may be machined after casting to achieve a finished state. Advantageously, casting of aluminum alloy allows for the formation of complex three-dimensional shapes.

[0012] Individual structural members of the side beams may further include one or more reinforcing members at each joint to support the large width of each suspension attachment point relative to the thickness of the central plate. In particular, the reinforcing members can increase the resistance of the side beams to bending stress and / or torsional stress. The reinforcing members may be formed from wrought aluminum alloy. For example, the reinforcing members may be formed by forging, extrusion, or other methods. They may then be machined into their final shape.

[0013] Each suspension mounting section of the side beam may have a base that forms a joint with each end of the central plate, the inside of which the base is joined to the upper surface of each end by one or more bolt connections passing through the base and the end, and one or more reinforcing components of each joint may include an auxiliary plate extending parallel to the central plate, the outside of which the base is joined to the upper surface of the auxiliary plate by one or more bolt connections passing through the base and the auxiliary plate. In other words, each suspension mounting section can be supported both internally (by the central plate) and externally (by the auxiliary plate). This configuration allows the joint to extend laterally, thereby helping the joint resist bending and torsional forces. The auxiliary plate may be spaced laterally from the central plate to further help resist these forces.

[0014] One or more reinforcing components of each joint may further include a rectangular brace having first and second wall portions for reinforcing an auxiliary plate to a central plate, wherein the first wall portion is joined to the outer surface of the central plate by one or more bolt connections passing through the first wall portion and the central plate, or can be joined in use, and the second wall portion is joined to the side of the auxiliary plate by one or more bolt connections passing through the second wall portion and the auxiliary plate. The rectangular brace can thus connect the auxiliary plate to the central plate and help the side beam to resist bending and torsional forces more effectively. Preferably, the rectangular brace includes one or more reinforcing webs extending between the first and second wall portions.

[0015] One or more steel reinforcing plates may extend across each joint between each end of the central plate and each suspension mounting point. This can be particularly advantageous when the structural members of the side beams are made of aluminum alloy. Steel is denser than aluminum alloy, but also stronger and more rigid. Therefore, the use of steel reinforcement across each joint can significantly strengthen the joint against bending and torsional forces and increase rigidity, while resulting in a relatively small increase in overall weight. In addition, steel reinforcing plates can help prevent separation of structural members at the joints under load from the vehicle body. Inner and outer steel reinforcing plates may extend across the inside and outside of each given joint.

[0016] At each joint, the lateral width of the suspension device mounting portion can be at least twice, preferably at least three times, the lateral thickness of the central plate.

[0017] The central plate may be tapered at its ends such that its vertical height is greater in the center than at its ends. This may also help increase the space below the suspension mounting section for joining the suspension elements to each wheelset.

[0018] Each bolted connection joining individual structural members of a side beam may be formed by a bolt that passes through at least one through-hole in one of the structural members and is received in a threaded receiving hole in another structural member or, when in use, in a crossbeam. By providing a threaded receiving hole, the bolted connection can be completed without using a nut. A helical insert, for example made of steel, may reinforce the threads of the receiving hole. This may be particularly advantageous in holes formed in aluminum alloy structural members.

[0019] Bolt connections joining individual structural members of a side beam may further include sensors for measuring axial strain in the bolts of the bolt connection. The sensors may be embedded in the bolts of the bolt connection. The sensors may be strain gauges, such as piezoelectric strain sensors.

[0020] According to a second aspect of the present invention, a bogie frame for a railway vehicle, comprising two side beams according to the first aspect of the present invention, defining respective lateral faces of the bogie frame with respect to the longitudinal direction of the railway vehicle, a cross beam extending across the railway vehicle for joining the side beams, and the cross beam being joined to a central plate of each side beam by respective bolt connections. A bogie frame for a railway vehicle is provided. Using bolt connections to join the cross beam to each side beam provides advantages, for example, compared to welded joints, as described in the first aspect above.

[0021] The bolt connections joining the cross beam to the central plate can transmit substantially all of the load between the cross beam and the central plate. In this way, these bolt connections can reduce or completely eliminate the need for other connection methods between the cross beam and the central plate.

[0022] The cross beam can be formed of an aluminum alloy. Again, this enables a lightweight structure with good mechanical properties.

[0023] The cross beam can be formed of a cast aluminum alloy. For example, the cross beam may be formed from a plurality of cast sub-components. The cross beam or its sub-components may be sand casting, die casting, continuous casting, pressure die casting, or one-shot casting. The cross beam or its sub-components may be machined to achieve the finished shape.

[0024] Each bolt connection joining the cross beam to one of the central plates can be formed by a bolt passing through a through hole in the central plate and received in a threaded receiving hole in the cross beam. By providing the threaded receiving hole, the bolt connection can be completed without using a nut. A helical, for example steel, insert can reinforce the threads of the receiving hole.

[0025] The bolt connection for joining the cross beam to the central plate may further comprise a sensor for measuring the axial strain in the bolts of the bolt connection. The sensor may be embedded in the bolts of the bolt connection. The sensor may be a strain gauge such as a piezoelectric strain sensor.

[0026] The bolt connection for joining the cross beam and the central plate may further comprise a shim disposed at the interface between the cross beam and the central plate. The shim can thereby fill any gap between the cross beam and the central plate and control the lateral spacing of the central plate. The shim may be surface treated, for example, ground and / or coated (e.g., painted), to increase the frictional interaction with the cross beam and the central plate, thereby transmitting the shear load between the cross beam and the central plate. In this way, the shim can help reduce the bending load on the bolt connection, which might otherwise lead to premature failure of the bolts.

[0027] According to a third aspect of the present invention, there is provided a bogie for a railway vehicle comprising a bogie frame according to the second aspect of the present invention and front and rear axles held by the bogie frame.

[0028] According to a fourth aspect of the present invention, there is provided a railway vehicle comprising one or more bogies according to the third aspect of the present invention.

[0029] The present invention includes combinations of the described aspects and preferred features, except where such combinations are clearly not permitted or are explicitly avoided.

[0030] Embodiments and experiments for explaining the principles of the present invention will be described below with reference to the accompanying drawings.

Brief Description of the Drawings

[0031] [Figure 1] A schematic side view of an end of a railway vehicle including a bogie is shown. [Figure 2] The bogie frame is shown in a perspective view. [Figure 3] The side beam of the bogie frame shown in FIG. 2 is shown in a perspective view. [Figure 4] The side beam shown in Figure 3 is shown in a top view. [Figure 5] Figure 3 shows an exploded view of the side beam. [Figure 6] Figure 3 shows an enlarged view of the central plate of the side beam. [Figure 7] Figure 3 shows an enlarged view of the auxiliary plate of the side beam. [Figure 8] Figure 3 shows an enlarged view of the rectangular brace of the side beam. [Figure 9] Figure 2 shows an exploded view of the trolley frame. [Figure 10] A part of the deformed bogie frame is shown in an exploded view. [Figure 11] The deformed side beam is shown in a perspective view. [Figure 12] Figure 11 shows a perspective view of the bogie frame, including the side beams. [Modes for carrying out the invention]

[0032] Further background, aspects, and embodiments of the present invention will be described below with reference to the accompanying drawings. Further aspects and embodiments will be obvious to those skilled in the art.

[0033] Figure 1 shows a schematic side view of the end of a railway vehicle 1 including a bogie 5. The bogie 5 is positioned beneath the railway vehicle 1 on the track 4. The bogie 5 comprises a bogie frame 10 that supports the floor of the railway vehicle 1 and holds two wheelsets 3. A further similar bogie (not shown) is provided at the other end of the vehicle. The bogie 5 provides stability, absorbs vibrations, and reduces the effects of centrifugal force in curved sections of the track 4.

[0034] Figure 2 shows a perspective view of the bogie frame 10. The bogie frame 10 comprises two side beams 20 and a cross beam 11. The two side beams define the respective lateral surfaces of the bogie frame with respect to the longitudinal direction L of the railway vehicle 1, and the cross beam extends across the lateral direction T of the railway vehicle to join the side beams.

[0035] The side beams 20 are formed from individual structural members made of aluminum alloy, as will be described in more detail below. The crossbeams may also be made of aluminum alloy. The crossbeams may be a single cast component or may be formed from cast subcomponents. For example, in Figure 2, the crossbeam 11 comprises four cast subcomponents 11a to 11d.

[0036] Figures 3 and 4 show examples of side beams 20 in perspective and top views, respectively. Figure 5 shows an exploded view of the side beam. Figures 6 to 8 show enlarged views of different individual structural members of the side beam. Figure 9 shows an exploded view of the bogie frame 10.

[0037] Each structural member of the side beam 20 includes an elongated central plate 21 extending in the longitudinal direction L, with the plate thickness direction being the transverse direction T, suspension device mounting sections 22 at both ends of the central plate, and additional reinforcing components 23, 24 at the joint between the central plate and the suspension device mounting sections. Most of the structural members of each side beam are joined to each other by smaller bolt connections 30, while each side beam is joined to each end of the transverse beam 11 at its central plate by larger bolt connections 14. However, as will be described below, some of these larger bolt connections 14 also have the additional function of joining the structural members of the side beam to each other.

[0038] Each suspension mounting section 22 includes a base 22a that forms a joint with each end 21a of the central plate, and a curved body section 22b to which a wheel axle suspension element (not shown) is attached. The suspension mounting sections 22 are made of cast aluminum alloy, the casting process being suitable for forming the relatively complex shapes of the mounting sections, and the aluminum alloy allowing for a combination of lightweight properties and good mechanical properties.

[0039] The suspension mounting section 22 is cantilevered from the central plate 21. In particular, the curved main body portion 22b rises upward and longitudinally away from the end 21a of the central plate 21, providing space below the suspension mounting section for the axle suspension elements to be positioned.

[0040] The base 22a of the suspension mounting section 22 has a wider lateral width than the thickness of the central plate 21. As a result, the suspension mounting section protrudes laterally outward at the joint with the central plate, with only the inner strip of each base 22a in direct physical contact with the upper surface of the central plate. Outside of this strip, each suspension mounting section is supported by additional reinforcing components in the form of auxiliary plates 23 and rectangular braces 24. At each joint, the lateral width of the suspension mounting section can be at least twice, preferably at least three times, the lateral thickness of the central plate. As best shown in Figure 4, the relative overall dimensions of the suspension mounting section and the central plate cause the side beam 20 to constrict in the middle of the central plate, leaving a protected space 25 outside the center of the plate for mounting equipment to the bogie frame 10. This space is particularly useful for mounting devices that are required or preferred to be mounted outside the bogie frame (e.g., yaw dampers and / or anti-rolling systems). In addition, the relatively thin thickness of the central plate 21 helps to reduce the structural weight of the side beams 20.

[0041] Each bolted connection 14, 30 comprises a respective fastening bolt 14a, 30a, which is typically inserted into a through hole in one component and screwed into a threaded hole in the other component (thus avoiding the need for a separate tightening nut to complete the bolted connection). Generally, multiple bolted connections are used to connect each pair of components to be joined, providing redundancy and reducing the load on individual connections. The threaded holes in the aluminum alloy components may be reinforced with helical steel inserts, such as Helicoil®.

[0042] The central plate 21 of the side beam 20 is formed of a wrought and machined aluminum alloy to increase strength and toughness. Referring to an enlarged view of Figure 6, the plate has through holes 21e and threaded receiving holes 21b for its bolt connections 30, and larger diameter through holes 21d for receiving larger diameter fastening bolts 14a. The central plate may have one or more gaps 21f to reduce the weight of the plate. Additional through holes 21c may be incorporated into the central plate for attaching additional articles to the side beam 20, as described below with respect to Figures 11 and 12. The central plate tapers at its ends 21a such that the vertical height of the central plate is greater in its central portion than at its ends. This increases the space below the suspension mounting portion 22 for joining the suspension elements to each wheelset.

[0043] The auxiliary plates 23 and rectangular braces 24 are also formed from wrought and machined aluminum alloy to enhance strength and toughness. Each auxiliary plate 23 is positioned parallel to the respective ends 21a of the central plate 21, but spaced apart laterally, and is joined to the base of the suspension mounting portion 22 by bolt connections 30 such that the outer strip of the base is in direct physical contact with the upper surface of the auxiliary plate. Each rectangular brace 24 has a first wall portion 24a joined to the central plate by bolt connections 14, and a 90° second wall portion 24b joined to the side of the auxiliary plate by bolt connections 30.

[0044] Referring to the enlarged view of Figure 7, each auxiliary plate 23 has through holes 23b and threaded receiving holes 23a, 23c for its bolt connections 30. Similar to the central plate 21, the auxiliary plates may also have one or more weight-reducing gaps 23e. Additional holes 23d may be incorporated into the auxiliary plates for attaching additional articles to the side beams 20, as described below with respect to Figures 11 and 12.

[0045] Referring to the enlarged view of Figure 8, the first wall section 24a and the second wall section 24b of each square brace 24 are reinforced and stiffened by one or more reinforcing webs 24c extending between the two wall sections. The brace has through holes 24f for its bolted connection 30 to the auxiliary plate 23 and through holes 24d for its bolted connection 14 to the central plate 21. The fastening bolts 14a of these bolted connections 14 are screwed through the through holes 24d and the aligned through holes 21d in the central plate, and then into threaded holes 11e in the crossbeam 11. They thus serve a dual function: joining the square brace to the central plate and joining the entire side beam to the crossbeam. Additional holes 24e may be incorporated into the square brace for attaching additional articles to the side beam 20, as described below with respect to Figures 11 and 12.

[0046] The spacing of the auxiliary plate 23 from the central plate 21, and its reinforcement by the square brace 24, increases the resistance of the side beam to bending and torsional forces.

[0047] The use of bolt connections 14 and 30 can simplify the assembly of the bogie frame 10, especially when the heads of the fastening bolts 14a and 30a are positioned to be easily accessible to the outside of the frame, allowing them to be tightened with conventional tools such as torque wrenches. The structural members of the side beams can also be easily replaced if they are damaged. This applies particularly to the auxiliary plates 23, which are most susceptible to damage from ballast collisions. In addition, the bolt connections can be easily accessed for safety inspections.

[0048] The bolted connection 14 may further include shims at the interface between the crossbeam 11 and the side beams 20. For example, as shown in Figure 9, the shim 14b is positioned on the inner surface of the central plate 21. The shims are used to fill the gap between the crossbeam and the side beams, thereby adjusting the lateral spacing between the central plates 21. Conveniently, each shim may be a washer into which the respective fastening bolt 14a is inserted. This ensures that the shim remains in place unless the bolt is removed. Advantageously, the shims may be surface-treated to increase frictional interaction with the crossbeam and central plate, thereby facilitating the transfer of shear load between the crossbeam and central plate, and thereby reducing the bending load on the bolts 14a.

[0049] Figure 10 shows an exploded view of a modified example of the bogie frame 10. In this modified example, the bolt connection 14 further includes a sensor 14c for measuring the axial strain of the fastening bolt 14a. In this way, the state of the bolt connection can be monitored. For example, the fastening bolt 14a may have a hollow section that houses a strain gauge (such as a piezoelectric strain sensor) having a connecting wire for supplying power to a gauge extending therefrom and for reading signals from the gauge.

[0050] Figure 11 shows a perspective view of a modified side beam, and Figure 12 shows a perspective view of the bogie frame including the side beam of Figure 11. In this modified version, the side beam 20 further includes steel reinforcing plates 25 to further strengthen the side beam against bending and torsional forces and to help prevent separation of the side beam structural members due to loads from the vehicle body. In particular, the steel reinforcing plates 25 can be attached to the inside and outside of the side beam so as to extend across the joint between the end 21a of the central plate 21 and the suspension device mounting portion 22.

[0051] Furthermore, bolt connections 25a may be used to join the reinforcing plate 25 to the side beam 20. In particular, the bolt connections may have fastening bolts that are inserted through holes in the reinforcing plate. On one side of each joint, these bolts are screwed into threaded holes 22c (see Figure 5) formed in the suspension mounting portion 22. On the other side of the joint, if the plate is on the outside of the side beam, the bolts are screwed into threaded holes 23d (see Figure 7) formed in the auxiliary plate 23, or if the plate is on the inside of the side beam, they are screwed into threaded holes 24e (see Figure 8) formed in the square brace 24 (in this case, the bolts also pass through through holes 21c formed in the central plate 21 - see Figure 6).

[0052] The features disclosed in the foregoing description, or in the following claims, or in the accompanying drawings, are expressed in terms of means for performing those particular forms or functions, or in terms of methods or processes for obtaining the disclosed results, and may be used, as appropriate, separately, or in any combination of such features, to realize various forms of the present invention.

[0053] While the present invention has been described in relation to the exemplary embodiments described above, many equivalent modifications and variations will be apparent to those skilled in the art if this disclosure is given. Therefore, the exemplary embodiments of the present invention described above are illustrative and not limiting. Various modifications to the embodiments described can be made without departing from the spirit and scope of the invention.

[0054] To avoid any doubt, all theoretical explanations provided herein are provided for the purpose of enhancing the reader's understanding. The inventors do not intend to be bound by any of these theoretical explanations.

[0055] The headings of any section used herein are for organizational purposes only and should not be construed as limiting the subject matter described herein.

[0056] Throughout this Specified Specification, including the claims set forth below, unless otherwise required by context, the words “comprise” and “include,” and their variations such as “comprises,” “comprising,” and “including,” will be understood to mean the inclusion of the given integer or step, or group of integers or steps, but not the exclusion of other integers or steps, or groups of integers or steps.

[0057] It should be noted that, as used in the specification and the appended claims, unless the context explicitly indicates otherwise, the singular forms “a,” “an,” and “the” refer to multiple objects. Ranges may be expressed herein as “about” a certain value to and / or “about” another specific value. Where such ranges are expressed, another embodiment includes a certain value to and / or another specific value. Similarly, where a value is expressed as an approximation by the use of the antecedent “about,” it will be understood that the particular value forms another embodiment. The term “about” is arbitrary with respect to a number and means, for example, + / - 10%. [Explanation of Symbols]

[0058] 1. Railway vehicles 3 wheelset 5 carts 10 bogie frames 11 Crossbeam 11e Threaded receiving hole 14-volt connection 14a bolt 14b Sim 14c sensor 20 Side beam 21 Center plate 21a End 21d through hole 22 Suspension device mounting section 22a base 23 Auxiliary plate 24-sided brace 24a First wall section 24b Second wall section 30-volt connection 30a bolt L Longitudinal direction T horizontal direction

Claims

1. A side beam of a bogie frame of a railway vehicle, wherein two such side beams define the respective lateral surfaces of the bogie frame with respect to the longitudinal direction of the railway vehicle, and a transverse beam extends laterally of the railway vehicle to join the side beams, and the bogie frame is configured to hold the front and rear axles when in use. The aforementioned side beam is an individual structural member, An elongated central plate extending between the first and second ends in the longitudinal direction between the positions occupied by the wheelset during use, wherein the thickness direction of the central plate is parallel to the transverse direction, A first and second suspension mounting section configured for attaching axle suspension elements, wherein the first and second suspension mounting sections are cantilevered from the first and second ends of the central plate, and each suspension mounting section extends upward and longitudinally away from its respective joint with the end of the central plate so as to define the space below the suspension mounting section for joining the suspension elements to the respective axles, and at each joint, each suspension mounting section has a width in the lateral direction greater than the thickness of the central plate so as to protrude outward in the lateral direction from the central plate, In order to support the large width of each suspension mounting portion relative to the thickness of the central plate, one or more reinforcing components are provided at each of the joints, It is formed from individual structural members, The individual structural members are joined to each other by their respective bolt connections. Each of the aforementioned bolt connections transmits substantially all of the load between the individual structural members. The central plate is made of wrought aluminum alloy, and the suspension mounting portion is made of cast aluminum alloy. Side beam.

2. The side beam according to claim 1, wherein each suspension device mounting portion has a base that forms the joint with the respective ends of the central plate, the inside of the base is joined to the upper surface of the respective ends by one or more bolt connections that penetrate the base and the ends, and the one or more reinforcing components of each joint include an auxiliary plate that extends parallel to the central plate, and the outside of the base is joined to the upper surface of the auxiliary plate by one or more bolt connections that penetrate the base and the auxiliary plate.

3. The side beam according to claim 2, wherein the one or more reinforcing components of each joint further include a rectangular brace having first and second wall portions for reinforcing the auxiliary plate to the central plate, the first wall portion being joined to the outer surface of the central plate by one or more bolt connections passing through the first wall portion and the central plate, or being joinable during use, and the second wall portion being joined to the side surface of the auxiliary plate by one or more bolt connections passing through the second wall portion and the auxiliary plate.

4. The side beam according to claim 3, wherein at each joint, the lateral width of the suspension device mounting portion is at least twice as large as the lateral thickness of the central plate.

5. The side beam according to claim 4, wherein the central plate tapers at its ends such that the height dimension of the central plate is greater at its central portion than at its ends.

6. The side beam according to claim 5, wherein each bolt connection is formed by a bolt that passes through at least one through hole in the structural member and is received in another structural member or in a threaded receiving hole in the crossbeam when in use.

7. A bogie frame for railway vehicles, Two side beams define each of the lateral surfaces of the bogie frame in the longitudinal direction of the aforementioned railway vehicle, A transverse beam extending laterally from the railway vehicle is used to join the two side beams. Equipped with, Each of the two side beams is a side beam according to any one of claims 1 to 6, The crossbeams are joined to the central plates of each side beam by their respective bolt connections. Bogie frame.

8. The trolley frame according to claim 7, wherein the bolt connection joining the crossbeam to the central plate transmits substantially all of the load between the crossbeam and the central plate.

9. The trolley frame according to claim 8, wherein each bolt connection joining the crossbeam to one of the central plates is formed by a bolt that passes through a through hole in the central plate and is received in a threaded receiving hole in the crossbeam.

10. The trolley frame according to claim 9, wherein the bolt connection that joins the crossbeam to the central plate further comprises a sensor for measuring the axial strain in the bolt of the bolt connection.

11. The bogie frame according to claim 10, wherein the bolt connection that joins the crossbeam and the central plate further comprises a shim disposed between the crossbeam and the central plate.

12. A railway vehicle comprising one or more bogies, wherein each bogie or bogie comprises a bogie frame as described in claim 11 and front and rear wheelsets held by the bogie frame.

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