EP3470294A1

EP3470294A1 - Bogie truck

Info

Publication number: EP3470294A1
Application number: EP17020475.4A
Authority: EP
Inventors: Alan Harding
Original assignee: Hba Rail Ltd
Current assignee: Hba Rail Ltd
Priority date: 2017-10-16
Filing date: 2017-10-16
Publication date: 2019-04-17

Abstract

A bogie for use in a railway vehicle having a vehicle body is described, the bogie comprising a pair of side frames 12 interconnected by a transverse bolster 14, the side frames 12 supporting therebetween at least one axle and wheel set 24, a mounting arrangement 32 whereby part of the vehicle body may be supported upon the bolster 14, the mounting arrangement 32 being articulated to allow tilting and other movement of the vehicle body relative to the bolster 14, in use, secondary springs 30 located between the bolster 14 and the vehicle body resisting such movement, and a variable damper 38 damping articulation of the mounting arrangement 32, wherein the variable damper 38 is adjustable such that the degree of damping can be adjusted depending upon whether or not the vehicle is laden.

Description

This invention relates to a bogie truck for a railway vehicle. In particular, it relates to a track friendly bogie truck, that is to say a bogie that, in use, results in relatively little wear to the tracks along which it runs, in use.
Over the last few decades, a number of track friendly bogie designs have entered into common use. By way of example, Powell Duffryn Rail have been supplying a bogie known as the TF25 which is a track friendly bogie. The low forces between the bogie and rails along which it is run not only results in reduced wear to the rails, but also results in less wear to elements of the bogie, such as the wheels thereof, and results in the generation of reduced noise levels, in use. The forces experienced by parts of the bogie, in use, are reduced, with the result that parts thereof may be of reduced size and weight. The bogie may thus be of relatively low weight, whilst still being able to bear high loads and can be operated at relatively high speeds, for example in the region of 120km/h when unloaded. Lower maximum operating speeds apply when laden.
In order to enhance operating efficiency, it is desirable to be able to maximise the speed with which rolling stock can be moved when unladen. The TF25 bogie is typically restricted to running at a top speed of 120km/h when unladen as mentioned above. The presence of a locomotive hauling wagons at this speed on a congested rail network is undesirable as it results in other trains, for example high speed passenger trains, being slowed. It is an object of the invention, therefore, to provide a bogie suitable for use in such applications and in which the maximum hauling speed when unladen is increased to reduce congestion and avoid unnecessarily slowing other trains using the track.
It has been found that under unladen, or tare, conditions, or when operating under a relatively low loading, a bogie is likely to suffer from increased plan view instability at high speeds. To counter this instability, yaw control dampers have been incorporated into bogies. Figure 1 illustrates, in plan view a bogie fitted with such yaw control dampers. As illustrated, the yaw control dampers 5 are connected between the ends of the bogie side frames 6 and other parts of the wagon. These dampers 5 damp the hunting or instability that occurs, but the presence of the yaw control dampers 5 adds weight to the bogie, and so reduces the maximum load carrying capacity of a wagon using the bogies, which is undesirable. Also, as the positions in which such dampers can be located is restricted through the need to avoid fouling with hopper doors or the like, they result in the effective length of the bogie being increased. The lengthening of the bogie, and restrictions in the positioned in which the dampers can be located, can result in an increase in the overall length wagon, which may in turn limit the number of wagons that may be used in a train, limiting the carrying capacity thereof. Another object of the invention, therefore, is to provide a bogie in which stability in plan view, when operating under tare conditions, is enhanced without the need to provide a yaw control damper.
According to the present invention there is provided a bogie for use in a railway vehicle having a vehicle body, the bogie comprising a pair of side frames interconnected by a transverse bolster, the side frames supporting therebetween at least one axle and wheel set, a mounting arrangement whereby part of the vehicle body may be supported upon the bolster, the mounting arrangement being articulated to allow tilting and other movement of the vehicle body relative to the bolster, in use, secondary springs located between the bolster and the vehicle body resisting such movement, and a variable damper damping articulation of the mounting arrangement, wherein the variable damper is adjustable such that the degree of damping can be adjusted depending upon whether or not the vehicle is laden.
By way of example, where the bogie includes a brake change over valve, operable to modify the applied braking loads depending upon whether or not the vehicle is laden, a connection may be provided between a brake change over valve and the variable damper.
Such an arrangement is advantageous in that, when the vehicle is operating under laden conditions and so yaw instability is not a significant problem, the variable damper need not provide a significant level of damping, and the bogie may operate in substantially the manner of a traditional bogie, for example in the manner of a known TF25 bogie or the like. When operating under low load conditions in which yaw instability is more of a problem, the damper may serve to damp the articulation between the vehicle body and the bolster to a greater degree, thereby reducing yaw instability. Switching of the damper between these operating modes may be achieved automatically upon switching of the brakes between the corresponding operating modes.
Compared to a traditional bogie, for example a traditional TF25 bogie or the like, the secondary springs are conveniently of a reduced stiffness. It should be noted that for a typical TF25 bogie, the unladen vertical stiffness is in the region of 6kN/mm (per spring) and the unladen lateral stiffness is in the region of 0.5kN/mm (per spring), and the secondary spring are preferably, in accordance with the invention, of lower lateral and/or vertical stiffness than this.
The invention will further be described, by way of example, with reference to the accompanying drawings, in which:

Figure 1 is a plan view of a bogie including a yaw control damper;
Figure 1a is a plan view, similar to Figure 1, illustrating a bogie in accordance with an embodiment of the invention;
Figure 2 is side view of the bogie of Figure 1a; and
Figure 3 is a front view of the bogie of Figure 1a.

Referring to Figures 1a to 3 of the accompanying drawings, a bogie 10 is illustrated that comprises a pair of side frames 12 interconnected by a transverse bolster 14. Each side frame 12 has a pair of axle box housings 16 pivotally connected thereto, primary suspension means in the form of springs 18 and dampers 20 being provided to allow damped vertical movement of the axle boxes 22 carried by the housings 16 relative to the bolster 14. It will be appreciated that the primary suspension means serves to accommodate disuniformities in the track.
The bogie 10 further comprises a pair of axle and wheel sets 24 that extend between the side frames 12, being supported, at their ends, by respective ones of the axle boxes 22.
Each side frame 12 has a brake arrangement associated therewith, including brake pads that may be driven or pushed against parts of the wheels to resist rotation of the wheels. As the brake loadings required vary significantly depending upon whether or not the vehicle of which the bogie forms part is laden, a brake switch over valve 26 is provided, the operation of which switches the operation of the brake arrangement between a low load setting and a high load setting, modifying the applied brake loadings to suit the load conditions under which the vehicle is being operated.
A vehicle body (not shown in detail in the drawings, but the underside of which is denoted by line 28) is supported upon the bogie 10. The underside of the vehicle body sits upon secondary springs 30 that, in turn, are supported upon the bolster 14. The secondary springs 30 conveniently take substantially the form shown in EP1093548 .
Compared to a traditional bogie of this general type, the secondary springs 30 are of a reduced stiffness, both in the vertical direction and in the lateral direction. In a traditional bogie of this general type, the unladen vertical stiffness of the secondary springs is typically in the region of 6kN/mm, and the lateral stiffness thereof is in the region of 0.5kN/mm.
The vehicle body is further supported upon the bolster 14 by an articulated mounting arrangement 32. The arrangement 32 comprises a fixing 34 attached, in use, to the underside of the vehicle body, the fixing 34 including a projection 36 that is received within a cavity formed in the bolster 14. The cavity is of a shape and size sufficient to allow limited movement of the fixing 34 relative to the bolster 14 to allow tilting of the vehicle body, and to allow limited angular movement between a longitudinal axis of the vehicle body and a longitudinal axis of the bogie 10, as may occur, for example, as the vehicle passes around a bend or curve in a track.
A damper 38 is provided to damp relative movement between the projection 36 and the bolster 14. The damper 38 may damp tilting movement, plan view yaw movement and other movements as permitted by the articulation of the mounting arrangement 32. The damper 38 is of a design such that the damping load applied thereby may be varied, and thus takes the form of a variable rate damper. In the arrangement illustrated, the damper 38 is connected, by way of a pneumatic line 40, to the brake switch over valve 26 such that when the brake setting is such that the brakes are operating in the vehicle laden operating mode, then the degree of damping applied by the damper 38 to damp movement between the projection 36 and the bolster 14 is relatively low. When the vehicle is being moved in an unladen condition, and the brake switch over valve 26 is positioned accordingly, then the damper 38 will apply a relatively large damping load. As a result, the damper 38 serves to counter the yaw instability that is typically experienced when the vehicle is moved at high speed under unladen or low load conditions.
It will be appreciated that the arrangement of the invention is advantageous in that plan view yaw instability, as often occurs with a vehicle of this general type when being moved at high speed under low load conditions, is countered without the need to add additional yaw stability dampers. Rather, the secondary springs and fixed rate lateral damper that would typically be provided are substituted for lower stiffness secondary springs and a variable damper, and control lines are added to allow control over the operation of the variable damper. The bogie in accordance with the invention may be of substantially the same weight as a traditional bogie as the only significant additional weight will arise from the provision of a length of hydraulic line providing a connection between the damper and the brake switch over valve. Yaw stability is enhanced without the need to provide a heavy yaw damper. As the weight of the bogie is not significantly increased, it will be appreciated that the benefit of the invention are achieved without the need to restrict the load carrying capacity of a wagon or the like incorporating the bogie. The invention may be retrofitted to existing bogies in a relatively straightforward manner.
It should further be noted that by avoiding the need to provide a yaw damper, the length of the bogie may be reduced. As a result, overall vehicle length may also be reduced, and this may allow trains to be formed form an increased number of vehicles, leading to an increase in capacity.
Whilst a specific embodiment of the invention is described herein, it will be appreciated that a wide range of modifications and alterations may be made to the arrangement described without departing from the scope of the invention as defined by the appended claims.

Claims

A bogie for use in a railway vehicle having a vehicle body, the bogie comprising a pair of side frames interconnected by a transverse bolster, the side frames supporting therebetween at least one axle and wheel set, a mounting arrangement whereby part of the vehicle body may be supported upon the bolster, the mounting arrangement being articulated to allow tilting and other movement of the vehicle body relative to the bolster, in use, secondary springs located between the bolster and the vehicle body resisting such movement, and a variable damper damping articulation of the mounting arrangement, wherein the variable damper is adjustable such that the degree of damping can be adjusted depending upon whether or not the vehicle is laden.
A bogie according to Claim 1, further comprising a brake change over valve operable to modify the applied braking loads depending upon whether or not the vehicle is laden.
A bogie according to Claim 2, wherein a connection is provided between the brake change over valve and the variable damper such that the damping load applied by the variable damper depends upon a brake setting.
A bogie according to any of the preceding claims, wherein the secondary springs are of a relatively low stiffness.
A bogie according to Claim 4, wherein the secondary springs are of relatively low vertical stiffness and of relatively low lateral stiffness.
A bogie according to any of the preceding claims, wherein no yaw control dampers are provided between the side frames and vehicle body.