WO1995008465A1

WO1995008465A1 - Rail vehicles

Info

Publication number: WO1995008465A1
Application number: PCT/GB1994/002044
Authority: WO
Inventors: Clive Graham Walker
Original assignee: Bombardier Prorail Limited
Priority date: 1993-09-23
Filing date: 1994-09-21
Publication date: 1995-03-30
Also published as: GB9319639D0; AU7661094A

Abstract

The invention relates to rail vehicles. Rail vehicles travelling on a curved track section, even at relatively modest speeds, are subjected to a rolling action and the passengers are subjected to centrifugal force. Rolling can be controlled by suspension systems and associated anti-roll bar systems, and the effects of centrifugal force can be countered by canting the track. With, such as, high speed trains, the above is not sufficient, and has led to proposals for tilting the rail vehicle body as it progresses around a curve. The object of the invention seeks to improve on known tilting means, an objective met by a construction of rail vehicle comprising a body (5), a body support assembly (1) and an anti-roll bar system (2-4, 6-15), characterised by the connection between the body (5) and the anti-roll bar system (2-4, 6-15) being adjustable to one or both sides of the body (5) to allow the height of the body (5) above the body support assembly (1) to at least one side, to be increased or decreased to a required degree, to cause tilting of the body (5) in relation to the body support assembly (1) in a required direction.

Description

RAIL VEHICLES

This invention relates to rail vehicles, and particularly to rail vehicles for passenger transport.

Rail vehicles travelling along a curved section of track even at relatively modest speeds are subjected to a rolling action, and there is considerable prior art relating to suspension systems with attendant anti-roll bar systems to control such rolling actions to within tolerable limits. However, even with effective roll control, there is the equally important factor, the subjecting of the passengers of the vehicle to the uncomfortable effects of centrifugal force that is progressively increased with increased speed. With such as high speed trains, the effect on passengers can be unacceptable.

This has led to various proposals to allow the deliberate tilting of the rail vehicle body inwardly in relation to the curve being traversed to compensate at least in part if not in full for the centrifugal acceleration felt by the passengers. For the most part, this has involved the employment of an inclined link system, with resultant structural complications to the vehicle that adds noticeably to costs and weight.

The object of the present invention is to provide a rail vehicle with an ability for the tilting of rail vehicle body, by a mechanism of notable simplicity, and relatively low cost, low weight and low size.

According to the present invention, a rail vehicle comprises a body, a body support assembly and an anti-roll bar system, the connection between the body and the anti- roll bar system being adjustable to one or both sides of the body to allow the height of the body above the body support assembly to at least one side, to be increased or decreased to a required degree, to cause a tilting of the body in relation to the body support assembly in a required direction.

The body support assembly may be a bogie, or may be axle boxes on the wheel sets. In either instance, the anti- roll bar system may have a torsion bar attached to the bogie/axle boxes with connecting means from each end of the torsion bar arms to the rail vehicle body, or may be attached to the rail vehicle body with a connecting means to each side extending to the bogie or the axle boxes. Thus, and as a rail vehicle enters a curve, the onset of centrifugal acceleration applied to the vehicle body can be sensed by appropriate sensors to determine the direction of induced centrifugal acceleration and its degree, and to cause either the raising of the height of the vehicle body in relation to the body support assembly to the outside of the curve, or the lowering of the vehicle body in relation to the body support assembly to the inside of the curve, to achieve the desired requirement of the tilting of the vehicle body inwardly in relation to the curve whereby to reduce substantially or eliminate the effect of centrifugal acceleration on the vehicle passengers. In the circumstance where a rail vehicle enters a curve that has the track canted and the rail vehicle is travelling at less than the equilibrium speed, the rail vehicle body is caused to lean inwardly of the curve, to the discomfort of the passengers. With the present invention, such as inward movement of the body, can be sensed, with an attendant raising of the body to the inside of the track or the lowering of the body to the outside of the track to eliminate the inward leaning of the body.

With relatively conventional anti-roll bar systems it is ordinarily the case that an arm is secured to each end of the torsion bar, and vertical links pivotally attached to ends of the arms. In the circumstance where the torsion bar is located on the body support assembly, the links extend upwardly to the body, and where the torsion bar is located on the body, the links extend down to the body support assembly. Thus, and in accordance with one aspect of the invention, one at least of the conventional vertical links can be replaced by an adjustable link that can be extended or contracted as required. Such an adjustable link can, for example, be in the form of a hydraulic jack with either an external hydraulic supply, or with an electric motor driven self- contained hydraulic system. Alternatively, an electric screw jack may be employed. Equally, an electric motor driven rack and pinion may be employed.

In accordance with a second aspect of the invention, a means of providing a controlled rotation of one half of an anti-roll torsion bar in relation to the other half can be provided, to cause a relative rotation of one of the arms secured to the anti-roll torsion bar to the other, and to cause the raising or the lowering of the vehicle body to at least one side through the interconnecting pivotal link, and hence provide the required tilting of the body inwardly of a curve being traversed. Thus, a two part torsion bar can be employed with an interposed rotary drive mechanism.

To provide control over the adjustable connection means between the rail vehicle body and the torsion bar, centrifugal acceleration sensing means can be provided, able to provide an output signal commensurate with the sensed acceleration. Said output signal can provide control over the power source for the adjustable link or links in terms of both degree and direction, to cause the tilting of the rail vehicle body into the curve to the degree required. Similarly, control can be provided over the rotary drive mechanism of a two part torsion bar arrangement, again in terms of both degree and direction to raise or lower the appropriate side of the vehicle body to tilt it into the curve.

Two embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:-

Figure 1 is a schematic representation of a linear system for the tilting of a rail vehicle body in a required direction; and Figure 2 is a schematic representation of a rotary system for the tilting of a rail vehicle body in a required direction.

As is shown schematically by Figure 1, a bogie 1 has mounted thereon a torsion bar 2, there being lever arms 3 to each side of the torsion bar, at one side pivotally attached to a connector rod 4 extending and being pivotally secured to the underside of a rail vehicle body 5, and at the other side pivotally attached to a linear actuator 6, the opposite side of which is pivotally attached to the underside of the rail vehicle body 5. Strategically located on the rail vehicle, such as on the body 5, is an accelerometor 7 connected to the linear actuator 6, such as by way of a microprocessor unit 8, that may also be located on the rail vehicle body.

The linear actuator 6 is a self-contained unit formed by a cylinder 9 having a hydraulic fluid reservoir, a motor-driven pump, and a control valve, the cylinder 9, being pivotally secured to the bogie unit 1, and the piston rod 10 emerging from the cylinder extending to and being pivotally connected to the rail vehicle body.

Thus, with the rail vehicle travelling at a particular speed and around a curve in the track of a particular radius and with the track at a particular cant angle, there is an acceleration force applied and sensed by the accelerometer 7, the output signal from which is passed to the processor means 8, programmed to provide a control signal to the motor and the control valve of the linear actuator 6 and such that the side of the rail vehicle to which the linear actuator is attached is raised or lowered to tilt the body to an appropriate degree in a required direction, to compensate for the acceleration applied to the rail vehicle body, and hence passengers inside the rail vehicle body, and to limit the side force applied to the passengers to acceptable levels.

In the alternative embodiment shown in Figure 2, there is again a bogie 1, an accelerometer 7 and associated processor means 8 located on the rail vehicle body 5. In this embodaiment, a two-part torsion bar 11, 12 is provided the inner ends of which are attached to a rotary actuator 13, the torsion bars and actuator being suspended below the underside of the rail vehicle body 5. To the outer end of each torsion bar part 11, 12 is a respective lever 14 pivotally attached to connecting rods 15 that extend to and are pivotally secured to the bogie 1. Here, and in common with the embodiment discussed in relation to Figures 1 and 2, the rail vehicle traversing a curve is subjected to an acceleration force that is sensed by the accelerometer 7, the output through which is passed through the processor means 8 to cause a required signal to be sent to the rotary actuator 13. The rotary actuator may then cause an opposite rotation of each torsion bar part 11, 12 in a required direction to cause the vehicle body to tilt in a required direction and to a required degree to reduce the applied force on passengers inside the rail vehicle body to be limited to acceptable levels.

Claims

1. A rail vehicle comprising a body, a body support assembly and an anti-roll bar system, characterised by the connection between the body and the anti-roll bar system being adjustable to one or both sides of the body to allow the height of the body above the body support assembly to at least one side, to be increased or decreased to a required degree, to cause tilting of the body in relation to the body support assembly in a required direction.

2. A rail vehicle as in Claim 1, characterised in that the body support assembly is a bogie.

3. A rail vehicle as in Claim 1, characterised in that the body support assembly is axle boxes on wheel sets.

4. A rail vehicle as in any of ClaJms 1 to 3, characterised in that a torsion bar of the anti-roll system is secured to the body support assembly, and has the said adjustable connection means between at least one end of the torsion bar and the body.

5. A rail vehicle as in any of Claims 1 to 3, characterised in that a torsion bar of the anti-roll system is secured to the rail vehicle body and has the said adjustable connection means between at least one end of the torsion bar and the body support assembly.

6. A rail vehicle as in Claim 4 or Claim 5, wherein the torsion bar has a lever arm at each end, pivotally attached to links that extend to and are pivotally connected to, either the rail vehicle body or the body support assembly, at least one of said links being adjustable.

7. A rail vehicle as in Claim 6, wherein the or each adjustable link has a powered extendible, or contractable, member to increase or decrease the length of the link, to raise or to lower one side of a rail vehicle body with respect to the other side of the rail vehicle body.

8. A rail vehicle as in any of Cla-ims 1 to 3, characterised in that a torsion bar of the anti-roll system is attached either to the body support assembly or to the rail vehicle body, each end of the torsion bar having lever arms to which are pivotally attached links that extend to and are pivotally secured to a respective rail vehicle body or body support assembly, the torsion bar being in two parts with an interposed means of providing controlled rotation of one half of the torsion bar in relation to the other half of the torsion bar, to raise or lower one of the links attached to one of the lever arms with respect to the other link attached to the other of the lever arms to raise or to lower one side of a rail vehicle body with respect to the other side of the rail vehicle body.

9. A rail vehicle as in any of Claims 1 to 8, characterised in that an accelerometer is provided to sense the degree and direction of a force causing a rail vehicle body to tilt outwardly or inwardly of a curve, said accelerometer providing an output signal to activate either the or each adjustable link, or the drive means interposed between the two relatively rotatable parts of the torsion bar to cause a raising and/or a lowering of one or the other sides of the rail vehicle body in accordance with the magnitude and the direction of the force sensed by the accelerometer.

10. A rail vehicle as in Claim 9, characterised in that a processor means is provided connected to the accelerometer, programmed to provide an output signal in accordance with the signal received from the accelerometer, to activate either the powered extendable/contractable link or the drive means interposed between the relatively rotatable parts of the torsion bar, to an extent and in a direction determined by the signal from the accelerometer.