GB2624683A

GB2624683A - Wheel assembly

Info

Publication number: GB2624683A
Application number: GB2217722.4A
Authority: GB
Inventors: John Kaye Michael; Campbell Archer Victor; Benjamin Smith George
Original assignee: Design Prototype Manufacture and Supply Ltd
Current assignee: Design Prototype Manufacture and Supply Ltd
Priority date: 2022-11-25
Filing date: 2022-11-25
Publication date: 2024-05-29
Also published as: GB202217722D0

Abstract

A wheel assembly (10) for a rail vehicle (20). The wheel assembly (10) comprises an outer shell unit (100) which defines an outer circumferentially extending surface (102) of the wheel assembly (10) and defines a support chamber (104) with an inner circumferentially extending surface (106). The outer shell unit (100) extends between a rail inner side end (108) and a rail outer side end (110). A shell support assembly (112) is located in the support chamber (104). The shell support assembly (112) comprises support ribs (200), each support rib (200) defining a support face (202), each support face (202) engaged with the inner circumferentially extending surface (106) at a different engagement position (114) on the inner circumferentially extending surface (106) of the outer shell unit (100). The engagement positions (114) are spaced around the circumferentially extending surface (102) of the outer shell unit (100).

Description

WHEEL ASSEMBLY

The present disclosure relates to a wheel assembly.

In particular the disclosure is concerned with a wheel assembly for a vehicle, where the wheel assembly is configured for travelling on railway track.

Background

Rail vehicles comprise wheels configured for running on metal rails. An essential requirement is that they should be hard enough to resist deformation, and so tend to be made from steel.

In some applications, for example rail handling equipment in the form of a transportation unit (that is, a vehicle in the form of a rail trolley) for moving and positioning of equipment on a railway track, it is important to keep the weight of the vehicle as low as possible. Indeed, to meet manual handling requirements, they typically need to weigh less than 50kg so they can be lifted by two men into position. Any heavier than this and alternative arrangements for handling the rail vehicle must be made, for example using a crane.

A significant source of weight of the vehicle is the wheels. For this reason, the wheels are not made of solid steel (as they normally would be) but of solid cast aluminium, which reduces the weight significantly since such vehicles tend to have at least four wheels, and hence any weight saving in one wheel is increased by a factor equal to the number of wheels.

However, a problem with using aluminium is that it is a relatively soft material, and when the rail vehicle is placed on the rail, the sudden point loading of the rail on the wheel surface causes it to deform at the point of contact. This reduces the ease with which the rail vehicle will roll along the track, and ultimately can result in failure or the wheel needing to be machined to bring it back to the desired geometry.

Conventional rail wheels may also comprise a brake unit. Since this is fitted to the vehicle at the same time as the brake unit, the brake unit must be torque tested when fitted to the rail vehicle also. This requires additional labour time on behalf of the fitter on the rail side, which can be inconvenient, especially if the test indicates any issues that must be fixed with the brake.

Hence a wheel for a rail vehicle which is significantly lighter than those of the related art and which do not suffer deformation as readily as examples of the related art is highly desirable. Additionally, -2 -a wheel which provides a means to ensure examples comprising brake units meet braking requirements before they are fitted to the rail vehicle, is also highly desirable.

Summary

According to the present disclosure there is provided a wheel assembly, a vehicle and a method of assembly as set forth in the appended claims. Other features of the invention will be apparent from the dependent claims, and the description which follows.

Accordingly there may be provided a wheel assembly (10) for a rail vehicle (20). The wheel assembly (10) may be centred on a central axis (30). The wheel assembly (10) may comprise an outer shell unit (100) which defines an outer circumferentially extending surface (102) of the wheel assembly (10) and defines a support chamber (104) with an inner circumferentially extending surface (106). The outer shell unit (100) may extend along the central axis (30) between a rail inner side end (108) and a rail outer side end (110). The wheel assembly (10) may also comprise a shell support assembly (112) located in the support chamber (104). The shell support assembly (112) may comprise support ribs (200), each support rib (200) defining a support face (202), each support face (202) engaged with the inner circumferentially extending surface (106) at a different engagement position (114) on the inner circumferentially extending surface (106) of the outer shell unit (100). The engagement positions (114) may be spaced around the inner circumferentially extending surface (106) of the outer shell unit (100).

The outer shell unit (100) may have a first radius R1 at the rail inner side end (108), and in a direction along the central axis (30) towards the rail outer side end (110), increases to a second radius R2 and then reduces to a third radius R3 towards the rail outer side end (110).

The outer shell unit (100) may comprise a support section (116) and may define a first opening (118) at a first end (120) and a second opening (128) at a second end (130). A first portion (122) of the support chamber (104) may extend between the first opening (118) and the second opening (128). The outer shell unit (100) may comprise a cap section (140) for engagement with the first opening (118) at the first end (120) of the support section (116), and which defines a second portion (132) of the support chamber (104). The cap section (140) may define the rail inner side end (108) of the outer shell unit (100). The second end (130) of the support section (116) may define the rail outer side end (110). -3 -

The outer shell unit (100) may define a torque tool engagement feature (160) for coupling with a torque test tool (800).

The support section (116) and cap section (140) may be joined together to define the outer circumferentially extending surface (102) of the wheel assembly (10).

The support section (116) may have a substantially constant wall thickness W along its length between the first opening (118) and the second opening (128).

The outer shell unit (100) may substantially comprise a first metal or a first metallic alloy.

The first metal or the first metallic alloy may comprise steel or high strength aluminium.

The shell support assembly (112) may substantially comprise a second metal or a second metal alloy.

The second metal or the second metal alloy may comprise aluminium.

The shell support assembly (112) may comprise nylon, ceramic or a fibre reinforced composite.

The first metal or first metallic alloy may be harder than the second metal or the second metal alloy. The first metal or first metallic alloy may have a higher density than the second metal or second metal alloy.

The rail inner side end (108) of the outer shell unit (100) may define rib engagement slots (142).

The rail outer side end (110) of the outer shell unit (100) may define rib engagement slots (142).

The support ribs (200) may be spaced equally around the inner circumferentially extending surface (106).

There may be provided at least ten but no more than twenty support ribs (200). -4 -

The wheel assembly (10) may further comprise a hub (300) located in the support chamber (104). The support ribs (200) may extend radially outwards from the hub (300) towards their respective engagement position (114) on the shell unit (100) inner circumferentially extending surface (106).

The hub (300) may define support rib engagement slots (302). Each of the support ribs (200) may extend from a different one of the support rib engagement slots (302).

The hub (300) may extend from the rail inner side end (108) to the rail outer side end (110) of the outer shell unit (100). The hub (300) may define a hub passage (306) which extends from the rail inner side end (108) to the rail outer side end (110) of the outer shell unit (100) for receiving an axle (700).

The inner circumferentially extending surface (106) at the rail outer side end (110) of the outer shell unit (100) may define a radially inward shoulder (150). The hub (300) and/or support ribs (200) may be located against the radially inward shoulder (150) of the outer shell unit (100) to thereby locate the shell support assembly (112) relative to the outer shell unit (100).

Each support rib (200) may extend along the central axis (30), from the rail inner side end (108) of the outer shell unit (100) to the rail outer side end (110) of the outer shell unit (100).

The wheel assembly (10) may further comprise a stiffening ring (400) which extends circumferentially around the central axis (30). The stiffening ring (400) may be fixed relative to each of the support ribs (200) to thereby hold the support ribs (200) a fixed distance relative to one another.

At least some of the support ribs (200) may define a stiffening ring slot (204) for receiving the stiffening ring (400). The stiffening ring slot (204) may extend from the radially outer side of respective support rib (200). The stiffening ring (400) may define a support rib slot (402) for receiving a support rib (200). The support rib slot (402) may extend from a radially inner circumference of the stiffening ring (400).

The stiffening ring (400) may be provided in at least two segments (404, 406) which, when assembled, form the stiffening ring (400). -5 -

The wheel assembly (10) may further comprise a load ring (500). At least some of the support ribs (200) may define a load ring receiving recess (206) for receiving the load ring (500). The stiffening ring slot (204) may extend from the load ring receiving recess (206) such that the load ring (500) is located between the stiffening ring (400) and the inner circumferentially extending surface (106) of the outer shell unit (100), and the load ring (500) is flush with the support face (202) of the or each support rib (200).

The support ribs (200) may comprise two flat parallel surfaces (208, 210). The support face (202) may extend between the two flat parallel surfaces (208, 210) The wheel assembly (10) may further comprise a brake unit (600). The brake unit (600) may comprise a brake unit rotatable section (602) and a brake unit non-rotatable section (604). The brake unit rotatable section (602) may be coupled to the hub (300) and the brake unit non-rotatable section (604) may be configured to be coupled to an axle (700) for rotatably supporting the wheel assembly (10).

There may also be provided a vehicle (20) comprising a wheel assembly (10) according to the present disclosure.

The vehicle (20) may be a rail transportation unit (20).

There may also be provided a method of assembly of a wheel assembly (10) for a rail vehicle (20). The wheel assembly (10) may comprise an outer shell unit (100) comprising a support section (116) and a cap section (140). The wheel assembly (10) may comprise a shell support assembly (112) comprising support ribs (200), a stiffening ring (400) and a load ring (500). Each support rib (200) may define a support face (202) for engagement with an inner circumferentially extending surface (106) of the outer shell unit (100). The wheel assembly (10) may comprise a hub (300). The method may comprise the steps of assembling the hub (300), support ribs (200), stiffening ring (400) and load ring (500); providing a bead of epoxy to support faces (202) of the support ribs (200); inserting the assembly into the support section (116) of the outer shell unit (100) to bring the support face (202) of each support rib (200) into engagement with the inner circumferentially extending surface (106) of the outer shell unit (100); locating support rib engagement slots (142) provided in the outer shell unit (100) with the support ribs (200); locating the cap section (140) on the support section (116); and joining the cap section (140) and support section (116). -6 -

Hence there is provided a wheel assembly for a rail vehicle which is significantly lighter than, and which does not suffer deformation as readily as, examples of the related art. Additionally, there is provided a wheel assembly which provides a means to ensure examples comprising brake units meet braking requirements before they are fitted to the rail vehicle.

Brief Description of the Drawings

Examples of the present disclosure will now be described with reference to the accompanying drawings, in which: Figure 1 is a side view of an example of a rail vehicle comprising a wheel assembly according to the present disclosure; Figure 2 is a perspective view of a wheel assembly according a first example of the

present disclosure;

Figure 3 is a side view of a wheel assembly as shown in figure 1; Figure 4 is a rail inner side end view of the wheel assembly shown in figure 1; Figure 5 is a rail outer side end view of the wheel assembly shown in figure 1; Figure 6 is an exploded side view of the wheel assembly shown in figure 1; Figure 7 is a side cross-section view of the wheel assembly shown in figure 1; Figure 8 is an exploded perspective view of the wheel assembly shown in figure 1; Figures 9, 10 are perspective views of a hub which forms part of the wheel assembly of both examples of the present disclosure; Figure 11 is a perspective view of a wheel assembly according a second example of the

present disclosure;

Figure 12 is a side view of a wheel assembly shown in figure 11; Figure 13 is a rail inner side end view the wheel assembly shown in figure 11; Figure 14 is a rail outer side end view the wheel assembly shown in figure 11; Figure 15 is an exploded side view of the wheel assembly shown in figure 11; Figure 16 is a side cross-section view of the wheel assembly shown in figure 11; Figures 17, 18 are exploded perspective views of the wheel assembly shown in figure 11; -7 -Figure 1915 a perspective view of the wheel assembly as shown in figure 11; Figures 20, 21 show the wheel assembly mounted in a torque tool; Figures 22 to 24 show different perspective views of a part of the torque tool shown in figures 20, 21; Figure 25 shows a mount part of the torque tool; Figure 26 shows an axle for use with the wheel assembly of the present disclosure.

Detailed Description

The present disclosure relates to a wheel assembly 10 for a rail vehicle 20. A wheel assembly 10 of the present disclosure may be first assembled and then fitted to a vehicle 20. In particular it may be fitted to a rail vehicle 20 or other equipment for travelling on a rail 14 (e.g. a rail transportation unit 20) for moving and positioning of equipment on a railway track 14. For example, as shown in figure 1, a wheel assembly 10 of the present disclosure may be included on a trolley type vehicle. The trolley may comprise a support frame 22 (e.g. supports for carrying the wheel assemblies 10) and a platform 24 fitted to the top of the support frame 22.

Alternatively the wheel assembly 10 may be fitted to any other kind of land (e.g. rail or otherwise) vehicle and/or other wheeled device, which may include, by way of non-limiting example, tool carts, trolleys, material handling tools, and scaffolding.

All of the wheels of the vehicle may be wheel assemblies according to the present disclosure. Alternatively at least one of the wheels of the vehicle may be a wheel assembly according to the present disclosure. In one example two of the wheels of the vehicle may be a wheel assembly according to the present disclosure. In alternative examples some, but not all, of the wheels of the vehicle may be wheel assemblies according to the present disclosure.

Figures 2 to 8 illustrate a first example of the wheel assembly 10 of the present disclosure. Figures 11 to 19 illustrate a second example of the wheel assembly 10 of the present disclosure. The examples have all the same features, although (as will be described) the arrangement of the component parts differs. The primary difference between the examples is that in the first example of Figures 2 to 8 the wheel assembly 10 is provided with a brake unit 600 on its rail outer side end 110, and in the second example of figures 11 to 10 the wheel assembly 10 is provided with a brake unit 600 on its rail inner side end 108. -8 -

The term "rail inner side end 108" refers to the side of the wheel assembly 10 which faces inwards (e.g. to between the tracks 14) and "rail outer side end 110" refers to the side of the wheel assembly 10 which faces outwards (e.g. away from the tracks 14). In other examples no brake unit 600 is provided. Hence the first example and second example may not have a brake unit fitted, and are otherwise as herein described.

As shown in the figures, the wheel assembly 10 is centred on a central axis 30. In use the wheel assembly 10 may be rotatable about the central axis 30.

As best shown in figures 6 to 8 and figures 15 to 18, the wheel assembly 10 comprises an outer shell unit 100 which defines an outer circumferentially extending surface 102 of the wheel assembly 10. That is, the outer circumferentially extending surface 102 is configured for engagement with the rail 14 (for example as shown in figures 3, 7, 12). The outer shell unit 100 defines a support chamber 104 with an inner circumferentially extending surface 106. The outer shell unit 100 extends along the central axis 30 between a rail inner side end 108 and a rail outer side end 110. Hence, as illustrated in figure 7, the support chamber 104 extends along the central axis 30 between the rail inner side end 108 and the rail outer side end 110.

As illustrated in figure 7, the outer shell unit 100 may have a first radius R1 at the rail inner side end 108, and in a direction along the central axis 30 towards the rail outer side end 110, increasing to a second radius R2 and then reducing to a third radius R3 towards the rail outer side end 110. R1 may have a value in the range of 25mm to 250mm. R2 may have a value in the range of 40mm to 350mm. R3 may have a value in the range of 25mm to 250mm.

As shown in figures 3, 7, and as conventionally is the case, the outer circumferentially extending surface 102 of the wheel is configured to interface with the rail 14 in a region between the second radius R2 and third radius R3.

As shown in figures 6, 7, 8 and figures 15, 16, 17, 18, a shell support assembly 112 is located in the support chamber 104. The shell support assembly 112 comprises support ribs 200, each support rib 200 defining a support face 202. For example, each support rib 200 may terminate at a support face 202. The support face 202 may be the edge of the rib 200. The support ribs 200 may comprise two flat parallel surfaces 208, 210. The support face 202 may extend between the two flat parallel surfaces 208, 210. The support ribs 200 may be formed (e.g. cut) from sheet metal. -9 -

Each support face 202 is engaged with the inner circumferentially extending surface 106 at a different engagement position 114 on the inner circumferentially extending surface 106 of the outer shell unit 100. There may be an interference fit between the support face 202 of the support rib 200 and the inner circumferentially extending surface 106 at the engagement position 114 of the outer shell unit 100, thereby contributing to resisting relative motion between the support ribs 200 and outer shell unit 100. Additionally a bond may be made between the support face 202 of the support rib 200 and the inner circumferentially extending surface 106 of the outer shell unit 100, for example with a bonding agent (e.g. an epoxy resin).

The engagement positions 114 are spaced around the circumferentially extending surface 102 of the outer shell unit 100. The engagement positions 114 may be equally spaced around the inner circumferentially extending surface 106 of the outer shell unit 100. In some examples the support rib 200 support face 202 may be in contact with inner circumferentially extending surface 106 along the full length of support rib 200. In other examples the support rib 200 support face 202 is in contact along a part of the inner circumferentially extending surface 106, for example in the regions which correspond to where the outer circumferentially extending surface 102 will interface with the rail 14.

Hence the wheel assembly is configured so that load on the outer shell unit 100 is transferred to the support ribs 200, putting them into compression.

The outer shell unit 100 may comprise a support section 116 which in use engages with the rail 14 and defines a first opening 118 at a first end 120 and a second opening 128 at a second end 130.

As illustrated in figure 7, a first portion 122 of the support chamber 104 may extend between the first opening 118 and the second opening 128 of the support section 116.

A cap section 140 may be provided for engagement with the first opening 118 at the first end 120 of the support section 116. As illustrated in figure 7, the cap section 140 may define a second portion 132 of the support chamber 104. The cap section 140 may define the rail inner side end 108 of the outer shell unit 100 and the second end 130 of the support section 116 may define the rail outer side end 110.

The support section 116 and cap section 140 may be joined together to define the outer circumferentially extending surface 102 of the wheel assembly 10.

-10 -As shown in figure 7, the support section 116 may have a substantially constant wall thickness W along its length between the first opening 118 and the second opening 128. The wall thickness W may have a value of at least 1mm and no greater than 6mm. The wall thickness W may have a value of at least 2mm and no greater than 4mm. The wall thickness W may have a value of at least 2mm and no greater than 3rnm.

The outer shell unit 100 may substantially comprise a first metal or a first metallic alloy. The first metal or first metallic alloy may comprise steel or high-strength aluminium.

The shell support assembly 112 may substantially comprise a second metal or a second metal alloy. The second metal or the second metal alloy may comprise aluminium.

The shell support assembly 112 may substantially comprise nylon, ceramic or a fibre reinforced composite.

Hence the wheel assembly may be a composite design. For example it may comprise a steel spun outer shell unit 100, supported by aluminium support ribs 200.

The first metal or first metallic alloy may be harder than the second metal or the second metallic alloy. For example the first metal or first metallic alloy (e.g. steel) may have a Brinell hardness in the range of 100 to 620, and the second metal or second metallic alloy (e.g. aluminium) may have a Brinell hardness in the range of 75 to 95.

The first metal or first metallic alloy may have a higher density than the second metal or second metallic alloy. For example the first metal or first metallic alloy (e.g. steel) may have a density in the range of 7000 to 9000 kg/m3, and the second metal or second metallic alloy (e.g. aluminium) may have a density in the range of 1000 to 5000 kg/m3.

The first metal or first metallic alloy may have a higher yield strength than the second metal or second metallic alloy. For example the first metal or first metallic alloy (e.g. steel) may have a yield strength in the range of 186 to 450 MPa and the second metal or second metallic alloy (e.g. aluminium) may have a yield strength in the range of 50 to 300 MPa.

The first metal or first metallic alloy may have a higher ultimate tensile strength than the second metal or second metallic alloy. For example the first metal or first metallic alloy (e.g. steel) may have a tensile strength in the range of 300 to 700 MPa and the second metal or second metallic alloy (e.g. aluminium) may have a tensile strength in the range of 80 to 400 MPa.

As shown in the example of figures 4, 8, the rail inner side end 108 of the outer shell unit 100 may define rib engagement slots 142. Alternatively or additionally, as shown in the example of figures 14, 17 the rail outer side end 110 of the outer shell unit 100 may define rib engagement slots 142.

The support ribs 200 may be spaced equally around the inner circumferentially extending surface 106. The slots 142 receive the support ribs 200 so as to prevent the ribs 200 from moving relative to the outer shell unit 100. That is to say, the slots 142 receive a part of (e.g ends of) the support ribs 200 so as to fix the support ribs 200 relative to the outer shell unit 100 to thereby prevent the ribs 200 from moving relative to the outer shell unit 100.

The wheel assembly 10 may further comprise a hub 300 which retains and locates the support ribs 200. An example of the hub 300 is shown in figure 9, 10. The hub 300 is located in the support chamber 104, the support ribs 200 extending radially outwards from the hub 300 towards their respective engagement positions 114 on the shell unit 100 inner circumferentially extending surface 106.

The hub 300 may define support rib engagement slots 302, each of the support ribs 200 extending from a different one of the support rib engagement slots 302.

The hub 300 may comprise a support base 308. The support rib engagement slots 302 may be defined in the support base 308. In the examples shown, the support base 308 is provided as a series of radially extending fingers which are spaced around the central axis 30. The hub base 308 may be provided in any suitable form. The hub 300 may also define a brake unit location cavity 310 for receiving the brake unit 600.

As shown in the examples of figures 2 to 8, the hub base 308 may be provided at the rail outer side 110. Hence in the examples of figures 2 to 8, the support rib engagement slots 302 are provided at the rail outer side 110.

-12 -As shown in the examples of figures 11 to 19, the hub base 308 may be provided at the rail inner side 108. Hence in the examples of figures 11 to 19, the support rib engagement slots 302 are provided at the rail inner side 108.

There are provided a plurality of support ribs 200. In the examples shown there are provided twelve support ribs 200. There may be provided at least ten but no more than twelve support ribs 200. There may be provided at least ten support ribs 200. There may be provided at least ten but no more than twenty support ribs 200.

The hub 300 may extend from the rail inner side end 108 to the rail outer side end 110 of the outer shell unit 100, and defines a hub passage 306 which extends from the rail inner side end 108 to the rail outer side end 110 of the outer shell unit 100 for receiving an axle 700. An example of an axle 700 is shown in figure 26. In one example the axle 700 is fitted (i.e. fixed relative to) the support frame 22 of the vehicle 20. Bearings (e.g. rotatable bearings) may be provided to rotatably support the wheel assembly 10 on the axle 700.

As shown in figures 7, 16, the inner circumferentially extending surface 106 at the rail outer side end 110 of the outer shell unit 100 defines a radially inward shoulder 150. The hub 300 and/or support ribs 200 may be located against the radially inward shoulder 150 of the outer shell unit 100 to thereby locate the shell support assembly 112 relative to the outer shell unit 100.

In the example of figure 7, the hub 300 is located against the radially inward shoulder 150 of the outer shell unit 100 to thereby locate the shell support assembly 112 relative to the outer shell unit 100. In the example of figure 16, the support ribs 200 are located against the radially inward shoulder 150 of the outer shell unit 100 to thereby locate the shell support assembly 112 relative to the outer shell unit 100.

Each support rib 200 may extend along the central axis 30, from the rail inner side end 108 of the outer shell unit 100 to the rail outer side end 110 of the outer shell unit 100.

As shown in figures 6 to 8 and figures 15 to 18, the wheel assembly 10 may further comprise a stiffening ring 400 which extends circumferentially around the central axis 30 and is fixed relative to each of the support ribs 200 to thereby hold the support ribs 200 a fixed distance relative to one another. That is to say, the stiffening ring 400 is fixed relative to each of the support ribs 200 to thereby hold the support ribs 200 a fixed distance relative to one another at their region of engagement with the stiffening ring 400.

At least some of the support ribs 200 define a stiffening ring slot 204 for receiving the stiffening ring 400, the stiffening ring slot 204 extending from the radially outer side of respective support rib 200. The stiffening ring 400 may define a support rib slot 402 for receiving a support rib 200. The support rib slot 402 may extend from a radially inner circumference of the stiffening ring 400.

As shown in figures 6, 8, 15, the stiffening ring 400 may be provided in at least two segments 404, 406 (for example as semi circles) which, when assembled, form the stiffening ring 400.

As shown in figures 6 to 8 and 15 to 17, the wheel assembly 10 may further comprise a load ring 500. At least some of the support ribs 200 define a load ring receiving recess 206 for receiving a load ring 500. The stiffening ring slot 204 may extend from the load ring receiving recess 206.

Hence, when assembled (as shown in figures 7, 16) the load ring 500 is located between the stiffening ring 400 and the inner circumferentially extending surface 106 of the outer shell unit 100. The load ring 500 may be flush with the support face 202 of the or each support rib 200. In use, the provision load ring 500 between the stiffening ring 400 and the outer shell unit 100 prevents the stiffening ring 400 causing a point load on the outer shell unit 100, thereby preventing a zone of high stress which may lead to failure of the outer shell unit 100.

As set out above, the wheel assembly 10 for rail vehicle 20 may further comprise a brake unit 600. The brake unit 600 may comprise a brake unit rotatable section 602 and a brake unit non-rotatable section 604. The brake unit rotatable section 602 (e.g. a brake drum) may be coupled to the hub 300. The brake unit non-rotatable section 604, which may comprise brake shoes for acting on the brake drum) may be configured to be coupled to an axle 700 for rotatably supporting the wheel assembly 10.

As shown in figures 4, 8, 11, 13, 17, 18 the outer shell unit 100 may define a torque tool engagement feature 160 for coupling with a torque test tool 800. The torque tool engagement feature 160 may be provided as an aperture, or series of apertures in the cap section 140 or support section 116. The torque test tool 800 may comprise teeth 164 or other extensions which extend through and engage with the engagement feature 160 of the outer shell unit 100.

In use, as shown in figures 20, 21, the wheel assembly 10, with brake unit 600 and axle 700 is rotatably mounted in a torque tool mount 802. The torque tool teeth 164 are engaged with the torque tool engagement feature 160 to fix the torque tool 800 relative to the outer shell unit 100. A torque wrench 804 is fitted to the torque tool 800. The brake of the brake unit 600 is applied to brake the outer shell unit 100 relative to the mount 802. A force may then be applied to the torque wrench 804 to seek to overcome the braking force of the brake unit 600. The torque is noted at which the outer shell unit 100 rotates relative to the mount 802. In this way the brake unit and wheel assembly may be tested "off site" (e.g. before delivery to where the wheel assembly is fixed to the trolley 20.

There may also be provided a method of assembly of a wheel assembly 10 for a rail vehicle 20. The method may comprise the steps of assembling the hub 300, support ribs 200, stiffening ring 400 and load ring 500, and then providing a bead of epoxy to support faces 202 of the support ribs 200. The assembly may then be inserted into the support section 116 of the outer shell unit 100 to bring the support face 202 of each support rib 200 into engagement with the inner circumferentially extending surface 106 of the outer shell unit 100.

The support ribs 200 may then be located in the support rib engagement slots 142 provided in the outer shell unit 100. The cap section 140 is then located on the support section 116. The cap section 140 and support section 116 are then joined. The cap section 140 and support section 116 may be joined by welding, in which case the weld may need to be machined to ensure the outer circumferentially extending surface 102 has the desired profile. A brake unit 600 may then be fitted, as required.

Since the wheel assembly of the present disclosure comprises an assembly of an outer shell unit and a shell support assembly 112 comprising support ribs 200, rather than being made of a solid casting, the wheel assembly of the present disclosure is significantly lighter than those of the related art.

For example, if an aluminium cast wheel of a particular design weight 4.5 Kg, a wheel assembly having the same external dimensions as the cast aluminium wheel but made according to the detail of the present disclosure, may weigh 2.0kg. Hence a four wheel rail vehicle would weigh 10kg less using wheel assemblies of the present disclosure compared to one using conventional cast aluminium wheels. This is a significant weight reduction when it is essential that the whole rail vehicle should weigh less than 50Kg to meet handling requirements.

-15 -Additionally a wheel assembly according to the present disclosure comprises less raw material than an example which is a solid casting, with consequential environmental benefits.

The material of the outer shell unit 100 is also chosen to resist deformation (that is, has a tensile strength / hardness which resists deformation when placed in contact with the rail) and hence may remain in service for longer than a conventional cast wheel before needing to be replaced.

Hence the composite wheel assembly of the present disclosure is much stronger and more hard-wearing than examples of the related art.

Additionally, there is provided a wheel assembly which provides a means to ensure examples comprising brake units meet a desired braking capability requirement before they are fitted to the rail vehicle since the efficacy of the wheel assembly brake unit may be tested in full before the wheel assembly is fitted to a rail vehicle.

Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

15 20 25 30

Claims

-16 -CLAIMS1 A wheel assembly (10) for a rail vehicle (20), the wheel assembly (10) being centred on a central axis (30), and the wheel assembly (10) comprising: an outer shell unit (100) which defines an outer circumferentially extending surface (102) of the wheel assembly (10) and defines a support chamber (104) with an inner circumferentially extending surface (106); the outer shell unit (100) extending along the central axis (30) between a rail inner side end (108) and a rail outer side end (110); a shell support assembly (112) located in the support chamber (104); the shell support assembly (112) comprising support ribs (200), each support rib (200) defining a support face (202), each support face (202) engaged with the inner circumferentially extending surface (106) at a different engagement position (114) on the inner circumferentially extending surface (106) of the outer shell unit (100), the engagement positions (114) being spaced around the inner circumferentially extending surface (106) of the outer shell unit (100).
2 A wheel assembly (10) as claimed in claim 1 wherein the outer shell unit (100) has a first radius R1 at the rail inner side end (108), and in a direction along the central axis (30) towards the rail outer side end (110), increases to a second radius R2 and then reduces to a third radius R3 towards the rail outer side end (110).
3 A wheel assembly (10) as claimed in claim 1 and claim 2 wherein the outer shell unit (100) comprises: a support section (116) and defines a first opening (118) at a first end (120) and a second opening (128) at a second end (130), a first portion (122) of the support chamber (104) extending between the first opening (118) and the second opening (128); a cap section (140) for engagement with the first opening (118) at the first end (120) of the support section (116), and which defines a second portion (132) of the support chamber (104); wherein the cap section (140) defines the rail inner side end (108) of the outer shell unit (100) and the second end (130) of the support section (116) defines the rail outer side end (110).
4. A metal wheel assembly (10) as claimed in claim 3 wherein the outer shell unit (100) defines a torque tool engagement feature (160) for coupling with a torque test tool (800).
-17 -A wheel assembly (10) as claimed in claim 3 or claim 4 wherein the support section (116) and cap section (140) are joined together to define the outer circumferentially extending surface (102) of the wheel assembly (10).
6 A wheel assembly (10) as claimed in claim 3, 4, 5 wherein the support section (116) has a substantially constant wall thickness W along its length between the first opening (118) and the second opening (128).
7 A wheel assembly (10) as claimed any one of the preceding claims wherein the outer shell unit (100) substantially comprises a first metal or a first metallic alloy and the shell support assembly (112) substantially comprises a second metal or a second metal alloy wherein: the first metal or first metallic alloy is harder than the second metal or the second metal alloy; and/or the first metal or first metallic alloy has a higher density than the second metal or second metal alloy.
8. A wheel assembly (10) as claimed in any of the preceding claims wherein the rail inner side end (108) of the outer shell unit (100) defines rib engagement slots (142).
9. A wheel assembly (10) as claimed in any of the preceding claims wherein the rail outer side end (110) of the outer shell unit (100) defines rib engagement slots (142).
10. A wheel assembly (10) as claimed in any of the preceding claims wherein the support ribs (200) are spaced equally around the inner circumferentially extending surface (106).
11. A wheel assembly (10) as claimed in any of the preceding claims wherein there are provided at least ten but no more than twenty support ribs (200).
12. A wheel assembly (10) as claimed in any of the preceding claims further comprising a hub (300) located in the support chamber (104), the support ribs (200) extending radially outwards from the hub (300) towards their respective engagement position (114) on the shell unit (100) inner circumferentially extending surface (106).
13. A wheel assembly (10) as claimed in claim 12 wherein the hub (300) defines support rib engagement slots (302), each of the support ribs (200) extending from a different one of the support rib engagement slots (302).
14. A wheel assembly (10) as claimed in claim 12 or claim 13 wherein the hub (300) extends from the rail inner side end (108) to the rail outer side end (110) of the outer shell unit (100), and defines a hub passage (306) which extends from the rail inner side end (108) to the rail outer side end (110) of the outer shell unit (100) for receiving an axle (700).
15. A wheel assembly (10) as claimed in any one of claims 1 to 14 wherein the inner circumferentially extending surface (106) at the rail outer side end (110) of the outer shell unit (100) defines a radially inward shoulder (150); and the hub (300) and/or support ribs (200) are located against the radially inward shoulder (150) of the outer shell unit (100) to thereby locate the shell support assembly (112) relative to the outer shell unit (100).
16. A wheel assembly (10) as claimed in any of the preceding claims wherein each support rib (200) extends along the central axis (30), from the rail inner side end (108) of the outer shell unit (100) to the rail outer side end (110) of the outer shell unit (100).
17. A wheel assembly (10) as claimed in any of the preceding claims further comprising a stiffening ring (400) which extends circumferentially around the central axis (30) and is fixed relative to each of the support ribs (200) to thereby hold the support ribs (200) a fixed distance relative to one another.
18. A wheel assembly (10) as claimed in claim 17 wherein at least some of the support ribs (200) define a stiffening ring slot (204) for receiving the stiffening ring (400), the stiffening ring slot (204) extending from the radially outer side of respective support rib (200); and the stiffening ring (400) defines a support rib slot (402) for receiving a support rib (200), the support rib slot (402) extending from a radially inner circumference of the stiffening ring (400).
19. A wheel assembly (10) as claimed in claim 17 wherein the stiffening ring (400) is provided in at least two segments (404, 406) which, when assembled, form the stiffening ring (400).
20. A wheel assembly (10) as claimed in claim 18, 19, further comprising a load ring (500); wherein at least some of the support ribs (200) define a load ring receiving recess (206) for receiving the load ring (500); the stiffening ring slot (204) extending from the load ring receiving recess (206) such that the load ring (500) is located between the stiffening ring (400) and the inner circumferentially extending surface (106) of the outer shell unit (100), and the load ring (500) is flush with the support face (202) of the or each support rib (200).
21. A wheel assembly (10) as claimed in any of the preceding claims wherein the support ribs (200) comprise two flat parallel surfaces (208,210), the support face (202) extending between the two flat parallel surfaces (208, 210)
22 A wheel assembly (10) as claimed in any one of the preceding claims further comprising a brake unit (600), the brake unit (600) comprising a brake unit rotatable section (602) and a brake unit non-rotatable section (604), the brake unit rotatable section (602) coupled to the hub (300) and the brake unit non-rotatable section (604) to be configured to be coupled to an axle (700) for rotatably supporting the wheel assembly (10).
23. A vehicle (20) comprising a wheel assembly (10) as claimed in any one of the preceding claims.
24. A vehicle (20) as claimed in claim 23 wherein the vehicle (20) is a rail transportation unit (20).
25. A method of assembly of a wheel assembly (10) for a rail vehicle (20), the wheel assembly (10) comprising: an outer shell unit (100) comprising a support section (116) and a cap section (140); a shell support assembly (112) comprising support ribs (200), a stiffening ring (400) and a load ring (500); each support rib (200) defining a support face (202) for engagement with an inner circumferentially extending surface (106) of the outer shell unit (100); and a hub (300), the method comprising the steps of: assembling the hub (300), support ribs (200), stiffening ring (400) and load ring (500); providing a bead of epoxy to support faces (202) of the support ribs (200); -20 -inserting the assembly into the support section (116) of the outer shell unit (100) to bring the support face (202) of each support rib (200) into engagement with the inner circumferentially extending surface (106) of the outer shell unit (100); locating support rib engagement slots (142) provided in the outer shell unit (100) with the support ribs (200); locating the cap section (140) on the support section (116); joining the cap section (140) and support section (116).