EP0229071A1

EP0229071A1 - Railway vehicle bogie

Info

Publication number: EP0229071A1
Application number: EP85905848A
Authority: EP
Inventors: Joseph Latham
Original assignee: Marmon Holdings UK Ltd
Current assignee: Marmon Holdings UK Ltd
Priority date: 1984-10-25
Filing date: 1985-10-25
Publication date: 1987-07-22
Also published as: KR870700527A; GB8526427D0; PT81376B; BR8507265A; GB2168663B; GB8426971D0; WO1986002609A1; AU5096585A; PT81376A; GB2168663A; ZA858218B; ES8703790A1; ES548240A0

Abstract

Un bogie de véhicule de chemin de fer (1) possède un châssis de bogie (2) fabriqué en une seule pièce, par ex. par moulage ou par usinage d'une plaque pleine. Le bogie peut comprendre des paliers (15) montés à l'intérieur des roues (4), contrairement aux bogies conventionnels où les paliers sont à l'extérieur des roues. L'utilisation d'un châssis monobloc est particulièrement avantageuse pour des bogies dont les diamètres des roues sont relativement petits, par ex. entre 300 et 650 mm.A railway vehicle bogie (1) has a bogie frame (2) made in one piece, e.g. by molding or by machining a solid plate. The bogie may include bearings (15) mounted inside the wheels (4), unlike conventional bogies where the bearings are outside the wheels. The use of a one-piece chassis is particularly advantageous for bogies whose wheel diameters are relatively small, e.g. between 300 and 650 mm.

Description

RAILWAY VEHICLE BOGIE

The present invention relates to railway vehicle bogie.

Freight carrying railway wagons are frequently of the type comprising two or more bogies each of which are pivotal relative to the wagon chassis to assist in the steering of the wagon around curves. Each such bogie comprises a bogie frame, which is pivotally mounted on the wagon chassis, and a plurality of wheel and axle units rotationally supported on the bogie frame.

Railway wagons for operation on any particular railway system must obviously be designed such that in the loaded or unloaded condition they will pass under or through all bridges or tunnels on the system with a minimum margin of safety between the vehicle or its load and the bridge or tunnel. Similarly, the vehicles must be able to travel around curves without ^•overhanging¹ to a degree which would cause danger to railway vehicles on adjacent tracks.

To meet these requirements, railway vehicles must be designed in accordance with the gauge requirements of the railway system on which they are intended to travel. Thus, in the U.K., freight carrying railway vehicle must be designed in accordance with W5 gauge and the concessions associated therewith. Other countries also have their own gauge requirements.

The load carrying capability of the railway vehicle may however be limited by the size of the vehicle wheels. For example, in the U.K., railway vehicles for carrying containers generally utilise a wheel diameter of 0.73m. In order to comply with W5 gauge, the current maximum height of containers to be transported by rail is about 2.55m. However various European countries now use containers of about 2.70m in height whereas containers available in the U.S.A. may be as high as 2.85m. such containers, (which may of course be imported into the U.K.) when loaded on currently available rail vehicles, do not lie within the U.K. W5 gauge and cannot therefore be transported by rail.

In order to increase the load carrying capactities of railway vehicles, whilst still conforming to the gauge requirements, it is necessary to construct a vehicle whereof the load carrying chassis is of lower height than in conventional railway vehicles. However, a simple reduction in the size of the conventionally used wheels and bogie frames does not provide a satisfactory vehicle since there are attendent problems associated with the use of smaller diameter and smaller bogies.

In particular we have established that the use of bogie frames which are of comparatively small depth and which have been fabricated by welding (i.e. the conventional way in which bogie frames are produced) has a number of disadvantages when used with small diameter wheels. In particular, the frame is liable to buckle by 20-30mm, which would be a significant proportion of the small-wheel diameter, and this may result in difficulty aligning various components to be mounted on the frame.

It is an object of the present invention to obviate or mitigate the above entioned disadvantage.

According to the present invention there is provided a railway vehicle bogie comprising a bogie frame adapted to be pivotally mounted relative to the chassis of the vehicle and having two rotatably supported wheel and axle units, wherein the bogie frame has been manufactured in one piece. The invention also provides a railway vehicle comprising a chassis and two bogie units as defined in the preceding paragraph pivotally mounted relative to the chassis.

By the term 'manufactured in one piece' we mean that the bogie frame is produced wholly in one piece and is not constructed from several sections which have been welded, bolted or otherwise joined together. Additionally any elements which are required for locating the essential suspension elements, e.g. springs, axle guides, axle box guides, are provided in the integral one-piece construction of the frame and are not welded, bolted or otherwise joined to the rest of the frame.

The bogie frame of the invention may be produced by machining a plate of the required material into the required configuration of the bogie. Alternatively, the bogie frame may be produced by casting, with a final machining if necessary.

The bogie frame may be manufactured from steel but is more preferably of aluminium in order to minimise weight.

The use of a one-piece bogie frame has a number of advantages. In particular the frame is not prone to buckling during manufacture (as is the case for welded frames). This avoids tolerance problems between components which are required to be attached to the frame and which, for example, are required to be in aligned relationship. A further advantage is that the integral construction of the frame allows it to be used as a jig facilitating the assembly of the other components of the bogie unit (e.g. springs, axle guides, axle box guides) onto the bogie frame. Furthermore the one piece construction means that the frame is substantially homogeneous and this means that the sectional properties of the frame are more tightly controlled (than in the case of frames produced by welding) resulting in more predictable behaviour of the frame. Finally, the one-piece frame is cheaper to construct than conventionally produced frames.

Preferably the bogie of the invention is constructed such that the wheel bearings are mounted inboard of the wheels is contrast to conventional bogies in which the bearings are outboard of the wheels.

The inboard mounting of the bearings enables the use of small-diameter wheels because of the profile of BR's (British Rail's) loading gauge. This is such that bogie components can be built nearer to the track inboard of the wheels than outboard.

The bogie of the invention will generally also incorporate brake means and suspension means

(preferably mounted inboard of the wheels). problem arises, however, with bogie units incorporating small diameter wheels in accordance with the invention. This problem relates to steerability of the unit, particularly at 'diamond crossings'. The problem arises because, when traversing a diamond crossing, the small wheels of a wheel and axle assembly of the bogie unit may, if the axles in this assembly are not restrained in substantially parallel relationship, align themselves such that the wheels tend to travel along the track which is being crossed. This can obviously lead to derailment of the railway vehicle.

In accordance with a preferred aspect of the invention the maintenance of each axle of the bogie in parallel relationship is assisted by respective pairs of track rods each mounted at one of their ends on the bogie frame and at the other of their ends on the axle or the associated axle boxes.

The use of the track rods ensures the the axles remain parallel within close tolerance limits and also increase the stiffness of the axles within the bogie unit to avoid mis-steer at diamond crossing.

Additional steps which may be taken to avoid missteering of the bogie include

(a) ensuring that the yaw stiffness of the bogie is as high as is compatible with steerability; and

(b) ensuring that the wheels on the same axle are as close to the same diameter as is possible to minimise out of balance effects. More particularly the valve of (the difference in diameter between wheels on the same axle should be less than 5 x 10~²cm.

The invention will be further described .by way of example only with reference to the accompanying drawings, in which:

Fig. 1 is a perspective view of one embodiment of one embodiment of bogie unit in accordance with the invention but omitting details of brakes and suspension for the sake of clarity.

Fig. 2 is a general arrangement part-sectional plan view of the construction of bogie unit shown in Fig. 1;

Fig. 3 is a detail of the bogie unit shown in Fig. 2;

Fig. 4 is a side view of the bogie unit shown in Fig. 2;

Fig. 5 shows the mounting of the wheel and axle of the bogie unit in bearings; and

Fig. 6 is a view of one of the wheels of the bogie unit;

The bogie unit 1 illustrated in Fig. i comprises a one-piece bogie frame 2 and two spaced wheel and axle units 3 with the wheels 4 of each such unit being of comparatively small diameter (e.g. 300mm) as compared to conventional sized railway wheels. The frame 2 is of a generally rectangular construction formed as a one piece aluminium casting, although may be produced by machining a plat of suitable thickness material. Typically, frame 2 would have a length of 2040mm, a width of 1670mm, and a depth of 145mm.

Referring now to Fig. 2, it will be seen that frame 2 is formed with four downwardly opening compartments 5 formed one at each corner of the frame 2 for the purpose of housing axle box units, in the manner to be described. Each compartment has an opening 6 at the associated side of the frame 2 and is also associated with a respective recess 7 located at that end of compartment 5 which is adjacent the other compartment 5 on that side of frame 2.

Each side of frame 2 has a centrally positioned section 8 for use in supporting brake arms and side-bearer assemblies, in the manner to be described.

Further features^'" of the frame 2 are a centrally located bearing support 9 for the pivotal mouning of the frame relative to a rail vehicle chassis, compartments 10 (for housing lateral dampers - to be described) each communicating with a compartment 5, recessed end sections 11 for locating anti-roll bars (to be described), and recesses 12 formed for the purpose of weight saving.

The axles 13 of the wheel and axle units 3 are journalled in axle boxes 14 located one in each of compartments 5 (see Figs. 2, 3 and 5). More particularly, the axles 13 are rotatably supported in roller bearing assemblies 15 of the axle box 9, and it will be noted that these bearings are located on the inboard side of the associated wheel 4. The bogie incorporates a primary suspension arrangement in which the axle boxes 14 are each suspended on the bogie frame 2 by respective pairs of suspension assemblies 16 located one on each side of the axles 13 and incorporating pairs of coil springs 17 surrounding hydraulic dampers 18. The lower ends of dampers 18 have eyelets 18a are mounted by pins 19 on the axle boxes 14 whereas the upper ends are located by a fastening arrangement 20 locating through the frame 2.

Each axle box 14 is associated with a track rod 21. These track rods comprise a central shank connecting, a first boss-like end 22a located on the axle box 14 and a second boss-like circular end 22b mounted on the frame 2. More particularly each boss-end 22a, 22b incorporates on annulus 23 of torsionally resilient material. The annuli of material 23 are each bonded to inner and outer steel sleeves, the outer one of which is an interference fit with the inner surface of the respective boss-end 22a or 22b. The boss-end 22a locates between a spaced pair of flanges 24 on axle box 14 and is mounted in position by a pin 25 which is an interference fit in the inner steel sleeve of annulus 23 and which is non-rotatably located through flanges 24. Boss-ends 22b each locate in a recess 7 and is located therein by a pin 26 which is an interference fit within the inner steel sleeve of annulus 23 and which is non-rotatably supported on frame 2.

The described construction of track-rod arrangement assists in maintaining the axles of the bogie in parallel within close tolerance limits and also increases the stiffness of the axle so as to avoid the possibility of mis-steer at diamond crossings.

Each wheel and axle unit 3 is associated with a lateral damper 27 (only one shown) constructed as dashpot assemblies located in a compartment 10 of the frame 2 and extending transversly to the bogies longitudinal centre line. One end (end 27a) of each damper 27 is mounted on the bogie frame 2 whereas the other end (27b) is mounted on an axle box 14 thereby providing a connection between the frame and the axle and serving to damp any lateral movement between the axles and the frame. More particularly, the end 27a is formed as an eyelet which locates in a recess 10a adjoining compartment 10 and is mounted the frame 2 by a non-rotatable pin 28 locating through eyelet 27a. The end 27b of damper 27 locates between a pair of flanges 29 formed as integral part of the axle box 14 and is mounted on these flanges by a non-rotatable pin 30.

Bogie unit 1 also incorporates a pair of anti-roll bars 31 (see Fig. 1) provided one in each of the recessed end sections 11 of frame 2. Each such anti-roll bar 31 locates through circular bearings (not shown) supported by bolts 32 and its ends extend into the compartments 5. Provided fast with the ends of anti-roll bars 31 are arms 33 each associated with a U-shaped bracket 34. A linkage 35 locating in the bracket 34 and also in a recess 36 of the axle box 14 serves to couple the anti-roll bars 31 to the axle box. Referring now to Fig. 4, it will be seen that the bogie incorporates tread brakes, and more particularly an in-line pusher brake assembly. This assembly comprises two brake arm 37 (each associated with a brake block unit 36) provided on adjacent sides of the wheels 4 and a brake cylinder 39, the actuation of which causes application of the brakes. More particularly, it will be seen that each brake arm 37 is pivotally mounted at its upper end on section 8 of bogie frame 2, and is pivotally attached at its lower end to the brake cylinder 39, the brake block units 38 are mounted on the arms, intermediate the ends thereof.

Hydraulic fluid used for the actuation of cylinder 39 is supplied thereto, and exhausted therefrom, along lines 40.

The bogie unit additionally includes at each side a further brake arm 41 and associated block unit 42 which are part of a hand-brake system of the bogie operated by a lever arrangement 43.

The bogie unit additionally includes side-bearer assemblies 44, the construction of which will not be described in detail.

As shown in the axial section of Fig. 6, each wheel 4 is formed with a flanged tread 45, a hub 46 (which is an interference fit on axle 9) and a web portion 47 connecting the tread to the hub 46.

Web portion 47 has inner and outer faces 47a and 47b respectively. The outer face 47b extends towards the inner face 47a in a curvilinear manner to a first point 48 from which the outer face 47b returns to the outer end of the hub 46. Similarly the inner face 47a extends towards outer face 47b in a curvilinear manner to a second point 49 which is beyond the first point 48. From this second point 49, the inner face 47a returns towards the inner end of the hub 46.

The above described arrangement in which points 48 and 49 are provided 'one beyond the other' gives a web 47 which has sufficient flexibility under working loads to 'absoro' stresses generated by braking of the wheel tread 45. Consequently, the forces transmitted to hub 46 are lessened thereby reducing problems associated with the destruction of the interference fit between the hub 46 and the axle 13.

Additionally, it will be noted that hub 46 is of a length which, in comparison to the depth of the wheel tread 45, is longer than normal. This helps to reduce the problems associated with destruction of the interference fit since forces transmitted to the hub are dissipated over a large area.

It should be appreciated that inner and outer faces 47a and 47b may be contoured so that point 49 may be above point 48.

Claims

CLAIMS :

1. A railway vehicle bogie comprising a bogie frame adapted to be pivotally mounted relative to the chassis of the vehicle and having two rotatably supported wheel and axle units, wherein the bogie frame has been manufactured in one piece.

2. A bogie as claimed in claim 1 wherein the frame has been manufactured by casting.

3. A bogie as claimed in claim 1 wherein the frame has been manufactured by machining.

4. A bogie as claimed in claim 1 wherein each wheel is jσurnalled in bearings positioned inboard of the wheel.

5. A bogie as claimed in claim 1 having a primary suspension arrangement located inboard of the wheels.

6. A bogie as claimed in claim 1 wherein each axle of the bogie is associated with track rods for assisting the maintenance of the axles of the bogie in parallel arrangement.

7^'. A bogie as claimed in claim 1 wherein each axle of the bogie is associated with lateral damping means.

8. A bogie as claimed in claim 1 wherein each axle of the bogie is associated an anti-roll means.

9. A bogie as claimed in claim 1 having an in-line pusher brake assembly.

10. A railway vehicle bogie as claimed in claim 1 wherein the wheels of the bogie have a diameter of 300 to 650mm.

11. A railway vehilcle comprising a chassis and two pivotally mounted bogies of the type claimed in claim 1.