GB1574598A - Powered rail vehicles - Google Patents

Abstract

The rail power unit has a vehicle body (1) and a bogie which, for the purpose of transmitting tractive forces and braking forces in a jolt-free fashion and in order to ensure easier access to the space in the central area of the bogie and to the components located in the space above said area, is coupled to the vehicle body (1) via two components (3) which are resilient in the longitudinal direction and are arranged in front of and behind the centre of the bogie. The said components (3) are each arranged between a part (16) of the bogie frame (14) and a rigid tractive-force transmission element (2) of the vehicle body (1), which element protrudes in front of and behind the centre of the bogie. The components (3) are preferably also of laterally resilient construction and arranged symmetrically with respect to the centre of the bogie so that the bogie can rotate about a central, imaginary, vertical axis with respect to the vehicle body (1). <IMAGE>

Description

(54) POWERED RAIL VEHICLES (71) We, SULZER BROS (UK) LIMITED, a Company registered under the laws of England, of Westmead, Farnborough, Hampshire, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to powered rail vehicles having bogies, and particularly but not exclusively to vehicles having three-axle bogies with separate traction motors for each axle.

According to the present invention, a powered rail vehicle includes a body, and a bogie which bears part of the weight of the body, and has first, second and third axles, at least one of which is driven, the bogie having a frame which is connected to the body for the transmission of traction forces therebetween by two longitudinally resilient connections, one situated between the first and second axles and on the longitudinal centre line of the vehicle, as seen in plan view, and one situated between the second and third axles, and on the longitudinal centre line of the vehicle, as seen in plan view, each resilient connection comprising at least one resilient component which is positioned between part of the bogie frame situated respectively between the first and second or between the second and third axles, as seen in plan view, and a rigid traction thrust bracket forming part of the body and also situated respectively between the first and second or between the second and third axles, as seen in plan view Both of the resilient connections should normally be so arranged that lateral movement can occur between the associated traction thrust bracket and the adjacent part of the bogie frame. In a preferred arrangement, the longitudinally resilient connections are also laterally resilient. Provided that the connections are symmetrically arranged about the bogie centre, swivelling movements of the bogie relative to the body will then take place, at least when no net lateral force is being transmitted between the body and the bogie, around a virtual centre of rotation situated at the physical centre of the bogie.This normally gives satisfactory behaviour of the bogie (i.e. small angle of attack, low flange forces and low flange wear) when running through curves.

The invention can be used in cases where it is necessary to leave the central area of the bogie free from obstruction, for example for access purposes. A particularly convenient location for the connections is in the transoms ahead of and behind the second axle. With the connections so arranged, good access to traction motors is possible, particularly if the rest of the secondary suspension is arranged to leave the space above the traction motors free of obtsruction.

In a preferred arrangement, the resilient connections between the body and the bogie are situated at a low level, for example, not higher than the centre line of the axles.

This is advantageous because it reduces the tilting torque which acts on the bogie frame when traction or braking forces are exerted, and therefore the transfer of load between the leading and trailing axles of the bogie is reduced. It will be appreciated that this is not possible when using a normal bogie pivot for a bogie having a motor positioned at its centre, unless the pivot is displaced longitudinally to clear the motor.

Preferably, each resilient connection comprises at least one elastomeric spring arranged between surfaces which face generally longitudinally of the vehicle. The elastomeric springs may, for example, be rubbermetal sandwich units.

The invention may be carried into practive in various ways, but one locomotive will now be described by way of example, with reference to the drawings accompanying the provisional specificaton, of which: Figure 1 is a vertical section through a bogie of a railway locomotive, taken on the longitudinal centre line, and also showing part of the underframe of the locomotive; Figure 2 is a plan view of the bogie; and Figure 3 is a cross-section through the bogie and the locomotive underframe, taken on the line III--III of Figure 1.

The bogie has three axles 10, each of which is driven by its own axle-hung tracton motor 12, The frame of the bogie is shown at 14, and is supported on the axles 10 by axleboxes and primary suspensions (not shown). Part of the body of the locomotive is shown at 1, and is supported directly on the bogie frame 14 by a secondary suspension (not shown). The secondary suspension carries practically the whole of the vertical load applied to the bogie by the body, and provides a vertically resilient connection between the bogie and the body, but it plays practically no part in the transmission of traction and braking forces between the body and the bogie. These forces are carried by rubber spring units whose arrangement will now be described.

The bogie frame 14 has two transoms 4, one on each side of the centre axle, as seen in Figure 2. Each transom 4 is divided over the central part of its length into two sideby-side structural members 16 between which a space 18 is formed which is approximately oval in plan view. Two traction thrust brackets 2 are fixed to and project downwards from the body 1, one into each of the spaces 18. Each bracket has two flat surfaces which face backwards and forwards respectively, and a rubber-metal sandwich spring unit 3 is received between each of these surfaces and a facing flat surface on the adjacent structural member 16.The spring units 3 are arranged to be in compression when no traction or braking forces are being transmitted between the body and the bogie, this precompression is made sufficent to ensure that all the spring units remain under some compressive stress under all operating conditions. The resilience of the spring units 3 in the longtudinal direction ensures that traction or braking forces are shared evenly between the two traction thrust brackets 2, so that the two transoms 4 are equally stressed.

The spring units 3 can also deform in shear to permit vertical, transverse and/or swivelling movements of the bogie relative to the body. The shear stiffness of the spring units 3 is fairly low, so that they cause little interference with these movements.

The secondary suspension, which in a typical example might incorporate rubber-metal sandwich spring units arranged with their tavers horizontal, also has a fairly low resistance to shear, and therefore causes little interference with transverse and/or swivelling movements of the bogie relative to the body. The lateral freedom allowed by the spring units 3 and the secondary suspension will normally be sufficient for good riding of the locomotive. If more lateral control is required for any reason, one or more vibration dampers, for example hydraulic dampers, can be connected between the bogie and the body, as shown as 19. Rubber buffers 5 are provided, one on each side of the traction thrust brackets 2, to limit lateral movement of the body relative to the bogie by contacting the internal surface of the space 18.It will be noticed that, with the bogie and body in their static positions, there is a clearance between the buffers 5 and the walls of the space 18, so that the buffers do not come into action for small movements; the buffers are of a conical shape, allowing a considerable deflection, so that their effect increases progressively as the relative displacement of the bogie and body increases. The drawings also show an alternative position 51 for the buffers 5.

The buffers 51 are mounted on brackets on top of the bogie frame 14, near the middle of its length, and engage with brackets projecting downwards from the locomotive body 1. In this position, the buffers are less affected by swivelling of the bogie, and have less tendency to cause tipping of the locomotive body 1 when they come into action.

If a swivelling movement occurs without any net lateral force being applied to the bogie, the lateral elastic forces acting on the two traction thrust brackets 2 must be equal and opposite, and therefore the lateral movements of the two transoms 4 relative to the traction thrust brackets must also be equal and opposite. In other words, the bogie has a virtual centre of rotation at its geometrical centre.

As can be seen from the drawings, the transoms 4 are so shaped that their middle portions, within which the spring units 3 are mounted, are at a considerably lower level than the rest of the bogie frame 14, and therefore traction and braking forces are transmitted from the bogie to the body of the locomotive at a fairly low level. This is advantageous because it reduces the tilting torque acting on the bogie and therefore reduces the amount by which the loads on the leading and trailing axles of the bogie will change when a traction or braking force is exerted.

It will also be seen from the drawings that the components by which traction and braking forces are transmitted from the bogie to the body (spring units 3 and traction thrust brackets 2) do not occupy any of the space directdly above any of the traction motors 12. The secondary suspension (not shown) is also arranged to leave this space clear, so that the traction motors can easily be lifted out of the bogie, after lifting the locomotive body off its bogies.

It will be appreciated that the invention may be applied to other forms of bogie than three-axle, three-motor bogies; for example it might be used in a monomotor bogie.

WHAT WE CLAIM IS:- 1. A powered rail vehicle including a body, and a bogie which bears part of the weight of the body, and has first, second and third axles, at least one of which is driven, the bogie having a frame which is connected to the body for the transmission of traction forces therebewteen by two longitudinally resilient connections, one situated between the first and second axles and on the longitudinal centre line of the vehicle, as seen in plan view, and one situated between the second and third axles, and on the longitudinal centre line of the vehicle, as seen in plan view, each resilient connection comprising at least one resilent component which is positioned between part of the bogie frame situated respectively between the first and second or between the second and third axles, as seen in plan view, and a rigid traction thrust bracket forming part of the body and also situated respectively between the first and second or between the second and third axles, as seen in plan view.

2. A vehicle as claimed in Claim 1 in which the longitudinally resilient connections are also laterally resilient.

3. A vehicle as claimed in Claim 2 in which the resilient connections are arranged symmetrically about the bogie centre.

4. A vehicle as claimed in Claim 1 or Claim 2 or Claim 3 in which the said parts of the bogie frame are constituted by two transoms, situated respectively between the first and second and between the second and third axles.

5. A vehicle as claimed in any of the preceding claims in which the lines of action of the resilient connections between the body and the bogie are situated at a low level.

6. A vehicle as claimed in Claim 5 in which the lines of action of the resilient connections are not higher than the centre lines of the axles.

7. A vehicle as claimed in any of the preceding claims in which the resilient connections comprise elastomeric springs.

8. A vehicle as claimed in Claim 7 in which each resilient connection comprises at least one elastomeric spring arranged between surfaces which face generally longitudinally of the vehicle.

9. A vehicle as claimed in Claim 7 or Claim 8 in which the elastomeric springs are rubber-metal sandwich units.

10. A powered rail vehicle having a bogie or bogies substantially as herein described, with reference to the drawings accompanying the provisional specification.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (10)

**WARNING** start of CLMS field may overlap end of DESC **. three-axle, three-motor bogies; for example it might be used in a monomotor bogie. WHAT WE CLAIM IS:-

1. A powered rail vehicle including a body, and a bogie which bears part of the weight of the body, and has first, second and third axles, at least one of which is driven, the bogie having a frame which is connected to the body for the transmission of traction forces therebewteen by two longitudinally resilient connections, one situated between the first and second axles and on the longitudinal centre line of the vehicle, as seen in plan view, and one situated between the second and third axles, and on the longitudinal centre line of the vehicle, as seen in plan view, each resilient connection comprising at least one resilent component which is positioned between part of the bogie frame situated respectively between the first and second or between the second and third axles, as seen in plan view, and a rigid traction thrust bracket forming part of the body and also situated respectively between the first and second or between the second and third axles, as seen in plan view.

2. A vehicle as claimed in Claim 1 in which the longitudinally resilient connections are also laterally resilient.

3. A vehicle as claimed in Claim 2 in which the resilient connections are arranged symmetrically about the bogie centre.

4. A vehicle as claimed in Claim 1 or Claim 2 or Claim 3 in which the said parts of the bogie frame are constituted by two transoms, situated respectively between the first and second and between the second and third axles.

5. A vehicle as claimed in any of the preceding claims in which the lines of action of the resilient connections between the body and the bogie are situated at a low level.

6. A vehicle as claimed in Claim 5 in which the lines of action of the resilient connections are not higher than the centre lines of the axles.

7. A vehicle as claimed in any of the preceding claims in which the resilient connections comprise elastomeric springs.

8. A vehicle as claimed in Claim 7 in which each resilient connection comprises at least one elastomeric spring arranged between surfaces which face generally longitudinally of the vehicle.

9. A vehicle as claimed in Claim 7 or Claim 8 in which the elastomeric springs are rubber-metal sandwich units.

10. A powered rail vehicle having a bogie or bogies substantially as herein described, with reference to the drawings accompanying the provisional specification.