GB2237544A - Low bogie structure for a railway vehicle - Google Patents

Abstract

A low bogie structure for a railway vehicle comprises two partial bogies (2, 3), each equipped with two wheel pairs, and an auxiliary frame (8), the wagon body being attached to the auxiliary frame and the frame being resiliently connected to the partial bogies. In each partial bogie (2, 3), one wheel pair (5, 7) is separately mounted and the other wheel pair is coupled to form a wheel-and-axle set (4, 6). The partial bogies (2, 3) are preferably interconnected by two crosswise bars (36a, 36b). <IMAGE>

Description

1 A low bogie structure The invention relates to a bogie structure for a

railway vehicle, the structure comprising two partial bogies, each provided with two pairs of wheels, and an auxiliary frame, the wagon body being attached to the auxiliary frame and this frame being resiliently coupled to the partial bogies.

The requirements, for example, of increasing the dimensions of goods to be transported by rail and of increasing their weight have continued to grow. The requirements of increasing both the outer dimensions and the quantity of goods to be transported presuppose decreasing the size of the bogie of a railway wagon, which thereby also tends to result in decreasing the diameter of the wheels. However, the carrying capacity of wheels with a smaller diameter is lower than that of a larger wheel; this leads to an increase in the number of wheels, as does also the increasing of the loading weight. Another factor requiring the development of the'structure is ever increasing travel speeds, at which the conventional structures no longer function in a satisfactory manner. Conventionally, especially the rolling surfaces of the wheels of railway wagons have been made conical in shape for steerability at curves. In theory, a wheel-and- axle set comprising two wheels and an axle fixedly interconnecting them functions at a curve so that the wheeland-axle set, when shifted outward, rolls with a larger diameter on the side of the outer curve than on the side of the inner curve, and thus it curves automatically. However, on a straight stretch and at a high speed this design leads to problems when the wheel-and-axle set begins by itself to rock from one side to the other, a phenomenon called sine run. This problem is the greater the higher the speed. If completely faultless travel at a curve is desired, the wheel-and-axle sets should steer themselves radially, i.e. the plane of the wheel should not form an angle of incidence with the track.

A i 2 Four-axle bogies have long been known per se. Their purpose has been to distribute the weight of the load among several wheels so that the load could be greater. The principal problem has in this case been to distribute the load equally among all the wheels. one such structure is disclosed in the publication US-2,242,371. This structure s in fact made up of a partial bogie, placed in the middle and equipped with two wheeland-axle sets, and two partial bogies placed at the ends and equipped with two wheel-and-axle sets, the latter thus being resiliently coupled to the partial bogie in the middle, so that the partial bogies can to a limited extent turn in relation to each other. otherwise the turning at curves has been made possible in a conventional manner, i.e. by allowing a movement of a wheel-and-axle set in the direction of its axle. This structure is very high, thus preventing effective use of space. In addition, at high speeds such a bogie suffers from the said sine-run problem.

The problem of load equalization is also dealt with in the publication DE1,930,290, in which the load introduced via a bogie-hub bearing is distributed among two double-axle partial bogies via ball bearings. Travel at curves has been made possible by each wheel-and-axle set being capable of turning on the horizontal plane. Each wheel-and-axle set is thus intended to be steered independently. The spring system which makes this possible also cushions it, and so radial steering is only partial. In addition, the said bogie structure suffers from the said sine-run problem in rapid drive. Furthermore, the structure of this bogie is also very high.

In the structures of the publications DE-2,919,635 and DE3,827,706, efforts have been made especially to improve behaviour at curves. In both of these, the bogie structure is made up of two partial bogies, each having two wheel-and-axle sets. These partial bogies are arranged to be at least to some 1 3 extent capable of turning in relation to each other, and, for steering, both structures use support beams on the sides of the partial bogies. Both of these structures evidently function reasonably at curves, owing to the radial steering between the partial bogies, but not in the best possible manner, since in the partial bogies the wheel-and-axle sets are not steered radially. On a straight track and at a high speed these bogies may at least to some extent suffer from unstable run, as do other similar prior-art structures. Furthermore, these structures are also very high.

The object of the invention is thus to provide a multiplewheel bogie structure which as a whole is as low as possible and makes possible a maximally large useful volume and useful height. The object is in particular a bogie the frame structure of which rises only to the level of the upper surface of the bearing structure of the wheels, or at most slightly higher, but remains clearly below the upper surface of the wheels. A further object is a bogie structure the carrying capacity of which is good and which thus distributes the introduced load very evenly among all the wheels, irrespective of any irregularities of the track. Furthermore, it is an object of the invention to provide a bogie structure which is effectively steerable at curves and in which all the wheels retain as pure a rolling state as possible, also at a curve. it is also an object of the invention to provide a bogie having good running properties, i.e. one in which vibration excitation for sine run is not produced even at high speeds and which thus runs steadily at speeds which could not be used with bogie structures according to the state of the art.

By the structure according to the invention, a crucial improvement is achieved with respect to the disadvantages mentioned above, and the objects described above are achieved. In order to accomplish this, the structure according to the invention is characterized in what is stated in the characteriz- 1 1 4

Claims (12)

ing clause of Claim 1. It can be deemed to be the most important advantage of the invention that a very low and space-saving bogie is obtained, which additionally carries the load well and is steered at curves without disturbance and without disadvantages of wear and loss of power, and can be driven on straight track portions at considerably high speeds, without problems. In addition the invention has the advantage that all of these effects can be achieved with a very simple structure. The invention is described below in detail with reference to the accompanying drawings. Figure 1 depicts a top plan view of a preferred embodiment of the bogie structure according to the invention. Figure 2 depicts a side view of the bogie structure of Figure 1, partly sectioned through A-A in Figure 1. Figure 3 depicts the bogie structure according to Figures 1 and 2, as seen in the longitudinal direction. Figure 4 depicts a partial section of the bogie structure of Figures 1-3, through C-C in Figure 1. Figure 5 depicts a partial section of the bogie structure of Figures 1-3, through B-B in Figure 1. Figure 6 depicts another embodiment of a detail of the spring system of the structure according to the invention, in the same representation as Figure 5. Figure 7 depicts another embodiment of a detail of the spring system according to the invention, in the same representation as Figure 5.

1 1 Figure 8 depicts a detail of the suspension of the springs, as seen from direction D in Figure 5.

Figure 9 depicts the embodiment of Figure 6, as seen from direction E.

Figure 1 shows the principal features of the most preferred embodiment of the bogie structure according to the invention. The bogie, which is indicated generally by reference numeral 1, comprises two partial bogies 2 and 3, each of which is equipped with two wheel pairs, i.e. the partial bogie 2 with wheel pairs 4 and 5 and the partial bogie 3 with wheel pairs 6 and 7. By a wheel pair is thus meant the two wheels on the same axle line. Each partial bogie thus has four wheels, and the entire bogie structure 1 has in total eight wheels. In addition the bogie structure 1 includes an auxiliary frame 8, to which the wagon frame, not depicted, is secured by mediation of, for example, a bogie hub 9. The ends 10, 11 of the auxiliary frame 8 extend to the area of the partial bogies 2 and respectively 3 and are resiliently linked to these partial bogies at points which are at a distance from each other in the transverse direction P, as described below in greater detail.

In each partial bogie 2, 3, one wheel pair 4 and respectively 6 is coupled by means of an axle 12 and respectively 13 between them to form a wheel-and-axle set. In addition, in each partial bogie one wheel pair 5 and respectively 7 is linked to the frame 14 and respectively 15 of the partial bogie concerned by means of separate bearings 16a-d and respectively 17a-d, these wheel pairs 5 and 7 having no axle interconnecting them. In this case, in each separately mounted wheel pair 5 and 7 the space between the wheels 18a and 18b and respectively between the wheels 19a and 19b is available for use. According to the invention, the ends 10, 11 of the auxiliary 6 frame 8, extending to the area of the partial bogies 2, 3, run.low, approximately at the level of the wheel axles 30, 31, which can be clearly seen in Figure 2. This is possible specifically because of the separate mounting. Thus the entire bogie structure will be very low, in which case even the bogie hub 9 is below the upper surface of the wheels, which provides a large load volume for the wagon frame.

These two partial bogies 2, 3 are interconnected by means of the auxiliary frame 8 in such a way that the separately mounted wheels 18a, b and 19a, b in each partial bogie face towards each other, whereas the wheel-and-axle set 6 consisting of the wheels 21a, b and axle 13 and respectively the wheel-and-axle set 4 consisting of the wheels 20a, b and the axle 12 will be in the bogie 1 at the ends facing away from each other.

In this case, when the bogie structure 1 is moving, and depending on the travel direction, the wheel-and-axle set 4 of the said partial bogie 2 will lead, and the separately mounted wheels 18a, b will trail, or the wheel-and-axle set 6 of the partial bogie 3 will lead and the wheels 19a, b will trail. Respectively, always depending on the travel direction, either the wheel-and-axle set 6 or 4 will trail in the bogie structure and the respective wheels 19a, b or 18a, b will lead. It has been observed that, evidently owing to the wheel-and-axle set leading, such a bogie structure is always steered at a curve effectively and with low friction, the separately mounted wheels rolling without a steering effect and always rolling at different speeds corresponding to the different radii of curvature on the two sides of the track. In addition, it has been observed that the bogie structure disclosed, specifically owing to the separately mounted wheels, will run straight on a straight track portion even at high speeds, without tending to sine run. It can even be said that the separately mounted wheels in this case attenuate or prevent the tendency to sine run. The behaviour at curves is also excellent for the reason n 1 7 that the partial bogies 2 and 3 are steered radially in relation to each other, as will be described below.

At the ends 10 and 11 of the auxiliary frame 8 which extend to the area of the partial bogies 2, 3 there are attached in the transverse direction P structural members, which are generally indicated by reference numerals 22 and 23. In the embodiments of Figures 1-6 these transverse structural members are transverse leaf springs 24. These transverse leaf springs 24, or a corresponding leaf spring stack, are rigidly attached to the end 10, 11 concerned of the auxiliary frame by means of bolts 25 or the like, or by clamping rings, or in some other known manner. By rigid attachment is meant an attachment which transfers moments. The ends of these leaf springs 24 bear on the frames 14 and 15 of the partial bogies 2, 3, preferably at a great distance from each other and from the centre line L of the wagon. Typically the leaf springs 24 are supported at their ends 26a, b at a point close to the wheels, and in each partial bogie approximately between two successive wheels 18a and 20a, 18b and 20b. 19a and 21a. and 19b and 21b. In general it is most advantageous to locate the effective vertical line 27 of the attachment point at a point which is in each partial bogie on a straight line drawn from the bearing centre point 28 of each wheel 20a, 20b, 21a and respectively 21b of a Wheel- and7axle set 4, 6 to the intersection point 29 of the plane of the rotation roller path and axle line of the separately mounted wheel 18a, 18b, 21a and respectively 21b successive to the said wheel in each given case, and in particular at the centre of this straight line. In this case the load introduced via the bogie hub is distributed equally among all the eight wheels.

According to a preferred embodiment, the leaf spring 24 is suspended in an articulated manner from the frames 14, 15 of the partial bogies, as is seen in Figures 5 and 8. This articulation structure 45 is in general shaped symmetrically around 1 8 the effective vertical line 27 in order to introduce the load at the desired point, as described above. This articulation structure is made up of a loop 32, which extends from below around the leaf spring end 26a, b and to above the bracket 33 in the frame of the partial bogie. Between the leaf spring end 26a, b and the lower part of the loop 32 there is a spherical surface 34, which is convex as seen from below. In other words, on the lower surface of the spring 24 there is a convex piece which presses against a stop surface, concave as seen from above, on the inner surface of the loop 32. Between the loop 32 and the bracket 33 there is a spherical surface 35, also convex as seen from below, there thus being in the loop 32 a surface convex as seen from below and in the bracket 33 on its upper surface a stop surface concave as seen from above. Thus, supported by two spherical surfaces, the load introduced to the auxiliary frame 8 via the bogie hub is 'Isuspendedll in a controlled manner from the brackets 33 of the partial bogie in such a manner that the effective vertical line 27 remains in place or at least returns automatically. The spherical surfaces allow movements caused by flexion and by irregularities in the track, as well as the turning caused by the radial steering of the partial bogies. This radial steering presupposes in particular that the leaf spring ends 26a, b can shift somewhat in the longitudinal direction L when the transverse direction P and thus also the lengthwise direction of the leaf springs, the leaf springs being rigidly attached to the auxiliary frame, form a somewhat small angle in relation to the axle lines 48, 50.

It is evident that the bogie according to the invention functions also when coupled merely in this manner, both partial bogies 2, 3 being interconnected by mediation of the auxiliary frame 8 via the transverse leaf springs 24, which are suspended by means of articulations to bear on the frames 14, 15 of the partial bogies, since in it the partial bogies can turn in relation to each other, i.e. be steered radially. This steer- 1 9 ing can, however, be produced more effectively by using crosscoupling, known per se. In the bogie structure according to the invention this cross coupling is achieved most advantageously by interconnecting the partial bogies 2 and 3 by crosswise bars 36a, 36b on those sides the partial bogie frames 14 and 15 which have the separately mounted wheels. In general it is most advantageous to connect the cross-coupling bars 36a, b to the inner bearing boxes of the separately mounted wheels, or in their vicinity, for example by means of articulations 51a-d. Thus the cross-coupling bar 36b is linked at the bearing box 16c by an articulation 51a and respectively in the other partial bogie at the bearing box 17b by means of an articulation 51c and respectively the cross-coupling bar 36a at the bearing boxes 16b and respectively 17c. In this case the cross-coupling bars can be made relatively short and extra space need not be left for them between the successive separately mounted wheels, i.e. between the partial bogies. In order to obtain as small a structural height as possible, it is advantageous either to make these cross-coupling bars to pass directly along the lower surface of the auxiliary frame 8 and to protect them with a base plate 37, or they can be made to pass respectively through the auxiliary frame 8 via openings in its walls for this purpose. The base plate 37 prevents vibration of the bars and makes the structure more rigid, and also in all circumstances prevents the bars from possibly shifting too low a position. Equipped with the cross-coupling bars, the partial bogies turn at curves in a manner known per se so that neither one of the partial bogies will form an angle of incidence relative to the track and thereby cause wear and losses of power.

In order to support laterally the wagon body, not shown, it is advantageous to provide in the auxiliary frame 8 protrusions 38a, b in the lateral direction, extending between the partial bogies as far as between the successive separately mounted wheels, i.e. the wheels 18a and 19a and respectively the 1 wheels 18b and 19b. At the ends of these branches 38a, b there are provided in a conventional manner supports 39a and 39b on which the wagon body will bear.

Figures 6 and 9 depict an alternative articulation structure 40 for a bogie structure in which a transverse leaf spring 24 is used, as above. This articulation structure 40 comprises, instead of a loop 32, a vertical rod 41 which passes through holes or a groove at the ends 26a, b of the leaf springs. The upper end of this rod rests on the partial-bogie body bracket 44 on the spherical surface 42, convex as seen from below, just as in the case of Figure 5. However, in this embodiment the supporting of the lower end is implemented by means of a spherical surface 43, convex as seen from above, in which case the concave surface 43 on the lower surface of the spring thus rests on an upward convex surface attached to the rod 41. Such an articulation structure thus works in the manner described above.

Figure 7 depicts an embodiment clearly different from the previous ones. In it the ends 10, 11 of the auxiliary frame 8 have been extended by fixed transverse beam protrusions 45 so that all the four ends 46 of the two beams in the structure substantially reach the points of the vertical lines 27, as in the case of the transverse leaf springs. These transverse beams 45 are either integral with the auxiliary frame or they have been attached to the auxiliary frame rigidly, as are the transverse leaf springs. The ends 46 of these transverse beams 45 are supported by means of schematically depicted springs 47 so as to bear on the frames 14, 15 of the partial bogies at the same points as the transverse leaf springs, i.e. at points at which the effective vertical line 27 is in the centre of a straight line plotted from the intersection point 29 of the plane 49 of the wheel rotation roller path 49 and axle line 50 of a separately mounted wheel to the bearing centre point 28 of the wheel-and-axle set subsequent to it. In this case the 4 line segments 28-27 and 27-29 are thus equally long, or almost equally long. The rubber spring 47 also results in a simple and effective structure because, when correctly designed and dimensioned, it forms both a spring and an "articulation system" which allows the movements on a horizontal plane, described above, due to the radial steering of the partial bogies, as well as the movements caused by other changes of position.

The invention is not limited to an embodiment or the embodiments described above; the structure can be varied within the limits defined in the patent claims. Thus, for example, the rubber springs can be replaced by helical springs and an articulation mechanism, although this alternative will most probably result in too complicated a structure. In the embodiments described, the force introduced via the bogie hub is distributed to the partial bogies via a total of four points. It is, however, conceivable that this load is distributed via only three spring- suspended points, in which case one partial bogie with its spring system would be as in the embodiment described but in the other partial bogie the end of the auxiliary frame would be spring suspended directly at approximately the centre of the partial bogie concerned. In this alternative the load is distributed more equally among the wheels during a run along a straight track, but especially in rapid run on a curve less equally, so that in principle it has both good and weak points. It is also conceivable to distribute the force among four points in such a manner that these four effective points are located elsewhere than the most advantageous point described above, but in general it is advisable to place these effective points in each partial bogie at least approximately on a line half-way between the two axle lines 48, 50 of the bogie concerned, and parallel to the axle lines. The spring suspension can also be distributed so as to be effective in series, at a number of points. For example, the auxiliary frame could be spring suspended relative to the transverse 4 12 leaf springs or the transverse beam, provided that the joint, in spite of the spring suspension, is sufficiently rigid, and -then to allow the leaf springs or rubber springs or the like to constitute the second suspension phase, as described above. The-load can be distributed between the partial bogies also via more than two points per partial bogie, for example four, in which case there would be a total of eight support points.

The steering of the partial bogies can further be perfected by making the attachment of the wheel-and-axle sets 4, 6 resilient. The separately mounted wheels 18a, b, 19a, b must indeed always be attached rigidly to the frames 14, 15 of the partial bogies in order to maintain the distance between the wheels fixed, but the wheel-and-axle sets can be arranged to be movable either in the axle direction or to be turnable on the horizontal plane, for example in the manner disclosed in the publication DE-1,930,290, or in some other manner. In this case the bogie structure 1 thus has two partial bogies which are steered radially under each other's influence, and both of these have radially steerable wheel pairs, in which case an angle of incidence cannot be formed at a curve, the rolling speeds of the wheels at each point correspond to the radius of the curve and, furthermore, the run is stable on a straight stretch and at a high speed.

It will of course be understood that the present invention has been described above purely by way of example, and mod. ifications can be made within the scope of the invention.

--- ------ -1. --- -- - 11 v 13 Claims 1. A bogie structure for a railway vehicle, comprising two partial bogies (2, 3), equipped with two pairs of wheels, and an auxiliary frame (8), the wagon body being attached to the auxiliary frame and the auxiliary frame resiliently to the partial bogies, characterized in that in each partial bogie (2, 3) one wheel pair (5,, 7) is separately mounted and the other wheel pair is coupled by means of an axle (12, 13) be tween the wheels (20a, b and respectively 21a, b) to form a wheel-and-axle set (4, 6).

2. A bogie structure according to Claim 1, characterized in that in the bogie structure the separately mounted wheel pairs (5, 7) in the partial bogies (2, 3) are at those bogie edges which face each other, and the wheel-and-axle sets (4, 6) are at those bogie edges which face away from each other, in which case, during run, the wheel-and-axle sets (4, 6) of the four successive wheel pairs in the bogie will always lead and, respectively, trail, and the auxiliary frame (8) can extend to between the separately mounted wheel pairs (5, 7) and in each partial bogie into the area between the axle lines (48) of the Wheel-and-axle sets and the axle lines (50) of the separately mounted wheels.

3. A bogie structure according to Claim 1, characterized in that at the first auxiliary-frame end (10), extending to the area of the first partial bogie (2), andlor at the second auxiliary-frame end 11. located at a distance from the former in the longitudinal direction (L) of the wagon and extending to the area of the second partial bogie (3), there is attached a transverse structural member (22, 23), of which at least one in the partiAl bogie concerned bears on the partial bogie concerned, at points which are at a substantial distance from each other in the transverse direction (P) of the bogie structure.

14

4. A bogie structure according to Claim 3, characterized in that that end (10 or 11) of the auxiliary frame to which no transverse structural member has been attached, is at that point resiliently attached to the partial bogie (2 or 3) concerned.

5. A bogie structure according to Claim 3, characterized in that the said first structural member (22) at the first end (10) of the auxiliary frame is rigidly attached to the auxiliary frame and bears at both its ends (26a, b; 46) resiliently on the first partial bogie (2) in the area between the successive wheels (20a, 18a; 20b, 18b) of this first partial bogie, and respectively at the other end (11) of the auxiliary frame the said second structural member (23) is attached to it rigidly and bears at both its ends (26a, b; 46) on the area between the successive wheels (19a, 21a; 19b, 21b) of this second partial bogie (3).

6. A bogie structure according to Claim 3, 4 or 5, characterized in that the said transverse structural member (22, 23) is a vertically resilient transverse leaf spring (24) which is by its centre rigidly attached to the auxiliary frame (8) and the outer ends (26a, b) of which bear on the partial bogies (2, 3).

7. A bogie structure according to Claim 6, characterized in that the members by means of which the ends (26a, b) of the transverse leaf spring (24) are supported to rest on the partial bogies are shaped as articulation structures (40) which allow a change of spring position due to the resilience of the leaf spring (24) and a change of the position of each partial bogie (2, 3) due to irregularities and curves in the track, and that this articulation structure (40) is a ball articulation structure in which the end of the leaf spring rests on a convex surface (34) or on a concave surface (43) against the stop surface of the support member (32, 41), and that this A 1 11 support member rests on a convex surface (35, 42) always against the stop surface in the given case of the partial bogie concerned.

8. A bogie structure according to Claim 3, 4 or 5, characterized in that the said transverse structural member (22, 23) is made up of a_transverse beam (45), which is at its centre rigidly attached to the auxiliary frame (8) and the outer ends (46) of which are supported by springs to bear on the partial bogie (2, 3) concerned, and that these springs providing the support are rubber springs (47) or other similar spring struc tures which make possible a change of position of each of the partial bogies, caused by irregularities and curves in the track.

9. A bogie structure according to any of Claims 3-8, characterized in that the said transverse structural members (22, 23) are made to bear on the partial bogies (2, 3) at least approximately at points which are always in each partial bogie in the area of a vertical line (27) running via the centre of a straight line plotted from the bearing centre point (28) of a wheel (20a, 20b, 21a, 21b) of the Wheel-and-axle set (4, 6) to the intersection point (29) of the plane (49) of the rotation roller path and the axle line (50) of the separately mounted wheel (18a, 18b, 19a, 19b) successive to this wheel.

10. A bogie structure according to any of the above claims, characterized in that the partial bogies (2, 3) are interconnected by means of two crosswise bars (36a, 36b), which are articulated (Sla-d) to the partial bogies in the vicinity of the inner bearings (16b, 16c, 17b, 17c) of their separately mounted wheels.

11. A bogie structure according to Claim 10, characterized in that the crosswise bars (36a, b) are supported by members (37) connected to the auxiliary frame or run through the auxiliary 4 A A 16 frame (8), and that the auxiliary frame has transverse branches (38a, b) extending to the area between the separately mounted wheels (18a, 19a; 18b, 19b), the wagon body being supported in the lateral direction by these branches.

12. A bogie structure substantially as hereinbefore described, with reference to figures 1 to 5 and 8, or to figures 1 to 4, 6 and 9 or to figures 1 to 4 and 7 of the drawings.

Published 1991 at7he Patent Office. State House. 66/71 High HoIborn. LondonWCIR47P. Further copies may be obtained from Sales Brwich. Unit 6. Nine Mile Point. Cwmfelinfach. Cross Keys, Newport, NPI 7HZ. Printed by Multiplex techniques Rd. St Mary Cray. Kent.