GB2143785A

GB2143785A - Railway vehicle suspension arrangement

Info

Publication number: GB2143785A
Application number: GB08416737A
Authority: GB
Inventors: Herbert Scheffel; Harry Marshall Tournay
Original assignee: South African Inventions Development Corp
Current assignee: South African Inventions Development Corp
Priority date: 1983-07-08
Filing date: 1984-07-02
Publication date: 1985-02-20
Also published as: BR8403388A; DE3424531A1; FR2548618A1; JPS6076465A; AU3034084A; GB8416737D0

Abstract

The arrangement has a frame 23 resting on an axlebox 10 through pads 27 formed of alternate layers of rubber and metal. Integral with the axlebox 10 is a stirrup 20 which pivots on a body 21 about a pin 34. In some embodiments the pin 34 is not required and the stirrup 20 and the body 21 are one with a pivot point at the centre of rotation of the pads 27. The stirrups 20 on the same side are connected by Watt's linkage with links 25 and a cross arm 36 pivoted to the frame 23. Other types of Watt's linkages are also disclosed. Diagonally opposed stirrups 20 are connected by coupling members 24. <IMAGE>

Description

SPECIFICATION Railway vehicle suspension Background to the invention This invention relates to railway vehicles and in particular to suspension structures for suspending them to axleboxes of wheelsets. The invention is applicable to railway vehicles in which a body or superstructure is pivotally supported on two bodies and to railway vehicles in which the vehicle body is directly supported on wheelsets, e.g. four-wheeled vehicles known in the art as "four-wheelers". Each wheelset has a pair of wheels fast with an axle.

In this specification and in the appended claims the term "railway truck" is defined to mean a railway unit including a frame supported on two wheelsets.

Thus a railway truck may be a bogie or a fourwheeler with the frame being the body in the event of a four-wheeler and being the frame in the event of a bogie.

Self-steering or radial railway trucks are known see e.g US patents Nos. 4067 261 and 4067 262 and many of them are in use on the South African railway system and elsewhere in the world. Such trucks rely on wheeltreads with a high effective conicity and a spring suspension which is soft in yaw thus allowing the wheeltreads to effect self-steering.

For stability purposes and to transmit longitudinal forces between the wheelsets interconnections of the kind shown in Figure 2 of US patent No. 4067 262 are used. It will be seen that this Figure illustrates a threepiece bogie.

When one attempts to apply the teachings of Figure 2 of this US patent to solid frame trucks, the absence of primary springing creates wheel unloading problems.

It is an object of the invention to provide a railway truck with a suspension which allows for selfsteering and also provides a primary suspension.

Summary of the invention The present invention provides a railway truck including: twp wheelsets, each having a pair of profiled wheels solidly mounted on an axle; a pair of axleboxes of each wheelset; a frame for distributing the truck load to the axleboxes; for each axlebox a stirrup which contains the axlebox and extends above and below the axis of the axle, means for generating a fulcrumpoint at the stirrup to allow the stirrup to swing longitudinally about the fulcrumpoint in relation to the frame; a first connecting point on the stirrup; means joining a pair of first connecting points and to transmit longitudinal forces between the wheelsets; and spring means between the frame and each axlebox allowing vertical relative movement between the frame and that axlebox.

Reference to "longitudinal" means in the direction of travel of the railway truck.

Afulcrumpoint may be generated in one of three ways: (a) by pivoting the stirrup about a transverse pivot on the frame: or (b) by pivoting the stirrup about a transverse pivot on a body sprung tq the frame by the spring means; or (c) by having the stirrup formed as an integral part of the axlebox and providing the spring means between the frame and the stirrup, thus allowing the stirrup to swing longitudinally and to move vertically relatively to the frame.

In the case of (a) and (b) the fulcrumpoint is at the axis of the pivot while in the case of (c) the fulcrumpoint is at the centre of rotation of the spring means.

The fulcrumpoint may be above or below the axis of the axle. If it is above, a negative, positive or zero springing effect may be achieved in the longitudinal direction.

Description ofthe drawings Figure 1 is a side view showing one stirrup configuration according to the invention; Figure 2 is a side view of a truck with a different stirrup configuration; Figures 3 to 7 are views similar to Figure 1 of other stirrup configurations; Figure 8 is a diagrammatic plan or underplan view of a truck in which axle boxes on the same wheelset are connected; Figure 9 is a diagrammatic side view of a truck showing a connection between wheelsets; Figure 10 is a plan view of Figure 9; Figure ii is a plan view of an alternative form of equaliser beam; Figure 12 is a diagrammatic plan view or underplan view showing another connection between wheelsets; and Figure 13 is a plan view of a bogie showing couplings between wheelsets.

Description of embodiments In Figure 1 an axlebox 10 on an axle 11 is mounted in an aperture surrounded by a stirrup 20 having two bowed sides 22 between which and the axlebox 11 there are spring pads 27 composed of layers of rubber interlined with metal plates to achieve the chevron shape illustrated.

The stirrup 20 is pivoted to a side frame 23 of a bogie about a fulcrum pin 28. The result is that the stirrup 20 can swing about the pin 28 and the axiebox 10 can yaw. Also the pads 27 allow relative vertical movement between the axlebox 10 and the frame 23.

The stirrup 20 carries two connecting pins 18 and 19 connected to elements 24 and 25 to be discussed later on.

In the embodiment of Figure 2 a stirrup 20 is shown integral with an axlebox 10 and pivoted about a pivot pin 34 on a body 21. Pads 27 spring the body 21 to the side of a frame 23. Once more the stirrup 20 carries pins 18 and 19 connected to elements 24 and 25.

The stirrup 20 can swing about the pin 34 and the pads 27 allow relative vertical movement between the frame 23 and the axlebox 10.

In the embodiment of Figure 3 a stirrup 20 similar to the one in Figure 2 is used, but it is firmly attached to a body 21 which is sprung to the frame 23 by means of the pads 27. The pads 27 are so chosen and arranged that their centre of rotation is at a point 35.

In the result the stirrup 20 can swing longitudinally about the point 35 as fulcrumpoint. The effect in Figure 3 is almost identical to that in Figure 2.

In Figure 4 the stirrup 4 is inverted as shown and has wings 29 on which the pads 27 rest. The frame 23 is formed with an extension 31 corresponding to the body 21 of the previous Figures. The centre of rotation of the pads 27 is at the point 35 about which the stirrup 20 can swing longitudinally against a spring effect which can be arranged to be negative, positive or zero.

In Figure 5 the extension 31 is replaced by a separate body 32 which is pinned to the frame 23 by means of a pin 33 at the centre or rotation 35 of the pads 27. The joint between the body 32 and the frame 23 is torsionally stiff. This may be achieved by bonding the pin 33 to the frame 23 by means of a rubber sleeve 34. The latter is bonded both to the pin 33 and the frame 23 while the pin 33 is fixed against rotation to the body 32 as by splines or the like.

In the above embodiments the pads 27 give soft vertical or primary springing and allow limited swinging of the stirrups 20 by compression of rubber along one edge of the pad and extension of the rubber on an opposed edge. The pad elements abutting the frame 23 and the opposed surface, e.g.

on a body 21, do not remain parallel to one another.

As the degree of non-parallelism increases, the degree of resistance from the rubber increases, so that there is a limit to the radius at which selfsteering is allowed to take place.

Figure 6 shows a solution to the just mentioned problem. In this case the outer metal layer 70 of each pad 27 is bolted to the frame 23. The inner metal layer 71 is formed with a clevis 72 fitting over an eye 73 on the body 21. A pin 74 pins the clevis 72 and the eye 73 together so that they can pivot about the pin 74.

If the stirrup 20 in the embodiment of Figure 6 swings about its fulcrum point 34 and pads 27 tend to lozenge. In other words the plates 70 and 71 remain parallel while the rubber in the pads is put into shear. This permits a greater degree of swinging and it is thus possible to use this embodiment on railway systems with very tight curves and still get self-steering of the wheelsets in those curves.

Figure 7 illustrates an embodiment similar to Figure 2, but in which the pads 27 are replaced by coiled springs 39 which are provided between the frame 23 and a spring support 30. The latter is anchored to the member 23 by means of a longitudinal anchor 41 secured to the frame 23 through resilient rubber washers 42 and having its axis in line with the centre of the pivot 34. A pin 19 has not been shown but it could be provided in the same way as in Figure 2.

All the embodiments of Figures 1 to 7 when fitted to a truck at its four profiled wheels of high effective conicity will allow selfsteering as a result of the gravitational forces generated by the wheel profiles.

In addition at each wheel there is an independent springing action, i.e. at each wheel the frame and axlebox can move vertically relatively to one another.

Due to the relatively low longitudinal stiffness of each suspension there can be longitudinal movement of the wheelsets relatively to one another and to the frame, such as during braking. The just mentioned problem has been solved in a satisfactory manner as disclosed in South Africa patent No.

82/6357 (corresponding to USSN 413409, filed August 1982) without affecting the steering property of the wheelsets of a self-steering bogie.

The solution proposed is to interpose a Watt's linkage between pairs of axle boxes. Figure 8 illustrates the case of a truck, most likely a fourwheeler, in which it would be impractical to have longitudinal connections between wheelsets. Followers 40 shaped as shown are pivoted on pin joints at centres 41 to the frame. Links 44 are pivoted on the pins 18 and to the ends of the followers 40 and 45. The joints at the ends of the links 44 are spherical.

The linkages shown limit the longitudinal movement of the wheelsets, e.g. during braking, relatively to one another and relatively to the frame.

Figure 2 illustrates another form of Watt's linkage in which links 25 are pivoted on the pins 19. A pair of links 25 are fitted to the pins 19 and to pivots on an arm 36 pivoted on the frame 23.

Figures 9 to 11 diagramatically illustrate other types of Watt's linkages which may be used.

In Figures 9 and 10 the stirrups 20 are connected by links 55 pivoted on the stirrups 20 and on pivoted arms 56. The arms 56 are pivoted to a balancing beam 59 pivoted to the centre of the truck frame about a pivot 60. Note that the links 55 on the two sides of the truck act on the arms 56 in opposite senses as shown. The device does not work if they act in the same sense.

A pivot 60 fixed on the frame may be too rigid especially for tight curves. In such a case a balancing beam 59 as shown in Figure 11 may be used. Here the centre of the beam 59 is rigidly connected to an arm 61 to another Watt's linkage, the links 62 of which are pivoted to the frame. In this case the beam 59 rests on brackets 63 carried by the frame. The interface between the beam 59 and the brackets 63 may be lined with a friction reducing material such as PTFE.

In Figure 12 links 57 are pivoted to cross-arms 58 pivoted on a balancing beam 59 which in turn may be pivoted to the truck frame or be supported in the manner shown in Figure 10.

As discussed in US patents Nos. 4067 261 and 4 067 262 self-steering trucks need devices to stabilise the wheelsets. Figure 13 shows an arrangement by means of which this is done. Cross-links are provided between the pins 18 of the stirrups 20. With a solid frame truck the links 24 are not required to give stability by generating creep forces. This may be provided by yaw dampers acting between axle boxes and the truck frame. However, the links 24 are often still necessary to keep the wheelbase intact under the action of single-acting brakes and to resist the slip forces which tend to yaw the wheelsets in the direction of increasing angles of attack when on-flange curving occurs such as in sharp curves or at turnouts at points and crossings. In the embodiment of Figure 2 the links 24 are retained. Yaw dampers may be mounted between the frame 23 and the axleboxes 10 as required.

Where space on a given vehicie design is limited and sharp curves are encountered, the preferred embodiment would have stirrups as illustrated in Figure 6, yaw dampers acting to damp yaw in both directions, the Watt's linkage of Figure 11 and cross-links 24 as illustrated in Figure 13.

Claims

1. A railway truck including: two wheelsets, each having a pair of profiled wheels solidly mounted on an axle; a pair of axleboxes on each wheelset; a frame for distributing the truck load to the axleboxes; for each axlebox a stirrup which contains the axlebox and extends above and below the axis of the axle; means for generating a fulcrumpoint at the stirrup to allow the stirrup to swing longitudinally about the fulcrumpoint in relation to the frame; a first connecting point on the stirrup; means joining a pair of first connecting points and to transmit longitudinal forces between the wheelsets; and spring means between the frame and each axlebox allowing vertical relative movement between the frame and that axlebox.

2. The truck claimed in claim 1 in which each stirrup is pivoted about a transverse pivot on the frame.

3. The truck claimed in claim 1 in which each stirrup is pivoted about a transverse pivot on a body between which and the frame the spring means is interposed.

4. The truck claimed in claim 1 in which one end of each stirrup is formed as an integral part of the axlebox and the spring means is provided between the frame and the stirrup, thus allowing the stirrup to swing longitudinally and to move vertically relatively to the frame.

5. The truck claimed in any one of the above claims in which the spring means includes a pair of pads with alternate layers of rubber and metal sandwiched between outer layers of metal.

6. The truck claimed in claim 5 in which on each pad one of the outer layers of metal is fixed to the member which it abuts and the other outer layer is pivotally connected to the member which it abuts about a pivot axis parallel to the wheel axis.

7. The truck claimed in any one of the above claims including a second connecting point on each stirrup on the same side of the axle as the first connecting point and means interconnecting the second connecting points on the wheelsets to couple yawing movements of the wheelsets in opposite senses.

8. The truck claimed in any one of the above claims in which the means for transmitting longitudinal forces between the wheelsets comprises a Watt's linkage connecting first connecting points on stirrups on the same side of the truck with its centre lever pivoted to the frame.

9. The truck claimed in claim 8 in which the Watt's linkage is vertical.

10. The truck claimed in claim 8 in which the Watt's linkage is horizontal.

11. The truck claimed in either of claims 9 or 10 in which the Watt's linkages are doubled with parallel links acting on crossed centre levers.

12. The truck claimed in claim 8 in which the centre iever is pivoted on a transverse balancing beam rotating about the bogie centre.

13. The truck claimed in claim 12 in which the Watt's linkage is horizontal.

14. The truck claimed in any one of claims 1 to 4 in which the means for transmitting longitudinal forces between the wheelsets comprises a follower above each axle pivoted to the centre line the truck, and links at the side of the truck pivotally connecting the first connecting points to the ends of the followers, so that the follower and the links form a Z in plan view.

15. The truck claimed in any one of the above claims including a yaw damper connected between each axlebox and the frame and acting to damp yaw in both directions.

16. A truck substantially as herein described with reference to any one of Figures 1 to 5, or any one of Figures 1 to 6 in combination with any one of Figure 7, Figures 8 and 9, Figures 8 and 10, Figure 11 or Figure 12.