GB2024124A

GB2024124A - Railway traction vehicle

Info

Publication number: GB2024124A
Application number: GB7918176A
Authority: GB
Original assignee: Brown Boveri und Cie AG Germany; BBC Brown Boveri France SA
Current assignee: BBC Brown Boveri AG Germany; BBC Brown Boveri France SA
Priority date: 1978-05-26
Filing date: 1979-05-24
Publication date: 1980-01-09
Also published as: FR2426600A1; GB2024124B

Abstract

In a high speed railway traction vehicle, a motor-gear unit assembly (6, 10) is suspended directly from the vehicle frame (13) by three swing arms (7,8,9). Two swing arms (8,9) are connected together with each other by means of a torsion bar (23) in such a manner as to allow only movement of the motor-gear unit assembly (6,10) which is transverse to the direction of travel, whereas the third swing arm (7) is mobile on all sides. At high speed travel on a straight rail (1) a rigid connection is made between the motor- gear unit assembly (6,10) and the vehicle frame (13) by way of a first transverse tie rod (12) with a lockable coupling element (21). At low speeds and on a curved rail (1), the coupling element (21) of the first tie rod (12) is released and simultaneously a second coupling element (22) in a second tie rod (14) is locked, so that a rigid connection between the motor-gear unit assembly (6,10) and the bogie frame (4) is made. Power is transmitted from the gear unit (10) to the drive wheels (2) by way of a hollow Cardan shaft (18) and universal couplings. <IMAGE>

Description

SPECIFICATION Traction vehicle This invention relates to a traction vehicle, in particular a railway traction vehicle, comprising bogie frames resiliently supported by wheel axles, a vehicle frame resiliently supported on the bogies, at least one motor having a gear unit rigidly flanged to the motor and disposed within the bogie frame in the vicinity of and parallel to the wheel axle driven by the motor, a three point suspension for the motor and gear unit, and a pivotable power transmission between the motor and the wheels.

In vehicles designed for high speeds, in particular railway traction vehicles, the so-called critical travelling speed must be set as high as possible by suitable constructional measures, in order to give calm undisturbed travel. The critical travelling speed is-the travelling speed at which the inherentfrequence of the bogie frame lies close to resonance, so that excitation results from the running of the wheel set or bogie. The higher the speed of travel, the higher the excitation frequency. For this reason it is advantageous for a traction bogie to have as low a mass as possible, so that its moment of inertia is small with respect to displacements transverse to its travel direction and with respect to rotation about its vertical axis.

In known traction vehicles, which at the present time are operating in great numbers, the motor with its gear unit is fixed in the bogie frame. Power transmission from the gear unit to the wheels or to the wheel axis then takes place advantageously through a Cardan shaft, which is preferably in the form of a hollow Cardan shaft. In this manner, the completely unsprung mass of such a traction vehicle consists only of the mass of the wheels, the wheel axle which joins them and a portion of the Cardan shaft.

Even on completely straight and flat rails, transverse and rotational movements occur in the bogie frame of a railway vehicle, these being known as sinusoidal motion. As the speed of travel increases, the forces and the excitation frequencies deriving from this sinusoidal motion become greater. To this must be added the forces generated due to the rail inaccuracies, rail joints, switching points and rail bends, leading to the occurrence of instability. This is particularly felt in the case of a traction bogie in which the motor is rigidly fixed to the bogie. In this case, the bogie mass is increase by the mass of the motor and gear unit, so increasing the unsprung or only partly sprung mass total. Such a construction is therefore unusable for vehicles which have to travel at high speeds substantially above the speeds usual at the present time.

A traction vehicle, in particular a railway traction vehicle is known, which is supposed to be suitable for high speed and in which the bogie mass is reduced by fixing the motor and reduction gear not to the bogie but to the vehicle frame, which is sprung with respect to the bogie. The motor and reduction gear are suspended on the vehicle frame at three points, one of the suspension points allowing rotation about a vertical axis, and the other two suspension points allowing translatory movement along the transverse and longitudinal axes of the vehicle frame, by which means expansion movements can be taken up which can be traced back to the heating of the motor and the power transmission. Power is transmitted from the gear unit to the driven wheels buy a Cardan shaft to a second gear unit fixed on the wheel axle.In order to take up the relative movement between the wheel axle and vehicle frame or motor which occurs when travelling round a bend, the Cardan shaft is constructed telescopically and consists of two parts which slide one in the other.

The advantages obtained from this known arrangement by fixing the motor and reduction gear to the vehicle frame, thus eliminating loadings of the bogie, are opposed by the disadvantages that the completely unsprung mass, in particular the transverse mass, of the driving wheel set is increased by a gear unit supported on the axle, that two gear units with five gear wheels are necessary, which means four tooth meshing portions with four back lash situations, and that the Cardan shaft has to be constructed in the form of a telescopic shaft. When such telescopic shafts slide in and out, friction forces occur which are dependent on the torque to be transmitted, and obstruct the movement. Furthermore, the weight of such a telescopic shaft is necessarily greater than the weight of an undivided Cardan shaft.

With a view to mitigating at least some of the above disadvantages the present invention provides a traction vehicle comprising bogie frames resiliently supported by wheel axles, a vehicle frame resiliently supported on the bogies, at least one motor having a gear unit rigidly flanged to the motor and disposed within the bogie frame in the vicinity of and parallel to the wheel axle driven by the motor, a three point suspension for the motor and gear unit, and a pivotable powertransmission between the gear unit and wheels, wherein the motor-gear unit assembly is movable suspendedby at least two swing arms and is connected by a first lockable transverse tie rod to the vehicle frame and by a second lockable transverse tie rod to the bogie frame, such that when travelling on a straight rail the first tie rod may be locked and the second tie rod is released to couple the motor to the vehicle frame, whereas when travelling on a curved rail the first tie rod may be released and the second tie rod locked to couple the motor for transverse movement with the bogie.

The invention uses the fact that extremely high travelling speeds are used only on straight rails. The amplitudes of the rotational and transverse movements of a bogie then lie within certain relatively narrow limits. In addition, high speeds are used only on specially prepared rails, so that other disturbing influences are small. When operating in this manner, the motor casing is rigidly coupled with the vehicle frame by the first transverse tie rod, and does not take part in any yawing movement of the bogie.

Relative movements between the bogie frame or drive wheel set and vehicle frame are balanced by the Cardan shaft and to a small extent by the vertical swing arms.

By contrast, when running on a bend the travelling speed is low, and larger bogie deflections take place.

When operating under these conditions, the first transverse tie rod is released and the second transverse tie rod produces a rigid coupling between the motor and bogie. The motor-gear unit assembly now swings completely with any deflection of the bogie.

By this means, that drive component which transmits the torque from the gear unit to the wheel axle, i.e. the Cardan shaft, so closely follows the relative axial movement between the driving wheel set and motor that the non-sliding maintenanceless universal couplings of the normal and well proven construction can be used.

Preferably, the motor-gear unit assembly is suspended on the vehicle frame by three swing arms.

By this means, the inherent movements of the motor-gear unit assembly are separated in a particularly effective manner from the movements of the bogie.

Preferably, a swing arm at the axle end and a swing arm at the motor end are connected together by a deflection stabilisation bar, so that they allow only movement of the motor-gear unit assembly which is transverse to the direction of travel. This ensures equal-phase deflection of the swing arms, and that the motor-gear unit assembly can swing only transversely to the direction of travel. By this means, deflections which for example are exerted by the Cardan shaft on the gear unit flange-connected to the motor, are uniformly transmitted to the total motor-gear unit assembly so that any too intensive twisting of the universal couplings is prevented.

Preferably, the transverse tie rods are pivoted to a swing arm at the axle end. In this manner, the motor-gear unit assembly completely follows the deflections of the bogie frame if rigidly coupled thereto, so that the universal couplings are not overloaded by the large deflections of the bogie when travelling round bends.

Further according to the invention, the motor-gear unit assembly is preferably suspended on the bogie frame at the axle end by two swing arms, and the third fixing point is in the form of a swivel joint and is fixed directly on the vehicle frame.

Preferably, the rotatable suspension point for the motor is fixed to the vehicle frame in the direct vicinity of the bogie swivel pin, or coincides with the bogie swivel pin. In this manner, at low speeds when the tie rod is rigidly coupled between the motor casing and bogie frame, there is practically no relative movement between the motor, gear unit and bogie frame, and the motor then seems to be rigidly fixed to the bogie at all points.

Preferably, mechanically, electromechanically, pneumatically or hydraulically lockable coupling elements are disposed in both transverse tie rods, The locking of these coupling elements can be made dependent on the amplitude of transverse movement and/or on the transverse force, which occur between the driving wheel set or bogie frame and the motor-gear unit assembly. Preferably, vibrationdamping devices are disposed between the motorgear unit assembly and the bogie frame and/or the vehicle frame. In this manner, in a preferred embodiment the lockable coupling elements themselves can additionally be formed as dampers.

The Cardan shaft is preferably a hollow shaft disposed concentrically to the wheel axle. By this means there is no need to dispose a second gear unit on the wheel axle, which would increase the unsprung mass. By suspending the motor-gear unit assembly on the vehicle frame, the play between the hollow Cardan shaft and drive axle must be greater than previously, as the axle suspension and the car body suspension are added.

Two embodiments of the invention are described in greater detail with reference to the drawing, in which: Figure 1 is a perspective partly diagrammatic, partly broken view of a portion of a traction bogie for a high speed vehicle, comprising a suspension with three swing arms directly connected on the vehicle frame.

Figure 2 is a perspective partly diagrammatic, partly broken view of a portion of a further traction bogie for a high speed traction vehicle comprising two swing arm suspensions connected to the bogie frame and a third suspension in the form of a swivel joint connected to the vehicle frame.

In Figure 1, in which the vehicle frame has not been drawn for reasons of improved visibility, rails 1 can be seen on which two drive wheels run. The drive wheels 2 are connected together by a wheel axle 20. A bogie frame 4 is supported by springs 3 on axle bearings 11. In the middle of the bogie frame 4 there can be seen a swivel pin 5, which makes the connection to the vehicle frame.

A motor 6 is disposed within the bogie frame. The motor 6 is suspended from the vehicle frame, which is indicated symbolically by mountings 13, by means of three swing arms 7, 8, 9. The swing arms 8, 9, which are connected together by a deflection stabilisation bar 23, allow the motor-gear unit assembly to move only transversely to the direction of travel, whereas the third swing arm 7 is mobile on all sides.

To this end the stabilisation bar 23 is rotatably pivoted in the mountings 13, and is rigidly connected to the swing arms 8, 9.

A reduction gear 10 is flanged to the motor 6, and consists of a motor pinion 15, an intermediate gear 16 and a greater gear 17, which are shown diagram- matically.

Power is transmitted from the greater gear 17 by way of a first universal coupling, not visible, to a hollow Cardan shaft 18 and byway of a second universal coupling 19 directly to one of the drive wheels 2. As already stated, such an arrangement of motor, Cardan shaft and driving wheel set has already proved very successful in the case of present-day traction vehicles, and thus it can also be used for a high speed vehicle.

The rigid connection between the motor-gear assembly 6, 10 and the vehicle frame 13 is attained at high running speed by way of a transverse tie rod 12 with a lockable coupling element 21. In this manner, the motor-gear unit assembly can be rigidly connected to the vehicle frame, and then takes no part in any movement of the bogie. Any relative movement between the driving wheel set and the vehicle frame is nullified by the universal couplings, the hollow Cardan shaft and the two swing arms 7,8 which are not connected to the transverse tie rods 12, 14.

When travelling on a curved rail and at low 'speeds, the coupling element 21 of the transverse tie rod 12 is released, and at the same time a coupling element 22 in a second tie rod 14 is coupled, so that a 'rigid connection is made between the motor-gear unit assembly 6, 10 and the bogie frame 4. The motor-gear unit assembly now follows the bogie deflections, and the Cardan shaft with its couplings now has to nullify only the relative movement between the driving wheel set and bogie. Vibration dampers are incorporated in order to dampen the inherent movements of the motor-drive unit assem buy6, 10 relative to the vehicle frame and bogie frame 4. For this purpose, it is for exam pie possible to use the lockable coupling elements 21,22, so that the coupling element which is not rigidly coupled acts as a damper.

Figure 2, in which the vehicle frame has again been left out for better clarity, shows the rail 1 on which the two drive wheels 2 run. The individual components of the traction bogie are indicated with the same reference numerals as in Figure 1, where these components are the same.

The motor 6 is supported on the vehicle frame (not shown) by a swivel joint 7 in the vicinity of the swivel pin 5. the axle end, the motor-gear unit assembly 6, 10 is suspended on the bogie frame 4 by two swing arms 28, 29.

The rigid connection between the motor-gear unit assembly 6, 10 and the vehicle frame 13 is made with the transverse tie rod 12 at high speed, by way of the lockable coupling element 21. In this manner, the motor-gear unit assembly becomes rigidly con nected to the vehicle frame 13, and takes no part in any bogie movement transverse to the direction of travel or about the swivel pin 5. Any relative movement between the bogie frame and vehicle frame is nullified by the vertical swing arms 28, 29.

As there is no rotational movement of the vehicle frame 4 about its transverse axis during high speed running on a straight rail, the fact that the motorgear unit assembly is suspended by about half its weight on the bogie frame leads to no disturbance.

When travelling on a curved rail and at low speeds, the coupling element 21 of the transverse tie rod 12 is released, and simultaneously the coupling element 22 in the second tie rod 14 is locked, so that a rigid connection then exists between the motorgear unit assembly 6, 10 and the vehicle frame 4. The motor-gear unit assembly now follows the bogie deflections, and the Cardan shaft 18 with its coupling 19 now has only to nullify the relative movement between the driving wheel set and bogie.

Claims

1. Atraction vehicle comprising bogie frames resiliently supported by wheel axles, a vehicle frame resiliently supported on the bogies, at least one motor having a gear unit rigidly flanged to the motor and disposed within the bogie frame in the vicinity of and parallel to the wheel axle driven by the motor, a three point suspension for the motor and gear unit, and a pivotable power transmission between the gear unit and wheels, wherein the motor-gear unit assembly is movably suspended by at least two swing arms and is connected by a first lockable transverse tie rod to the vehicle frame and by a second lockable transverse tie rod to the bogie frame, such that when travelling on a straight rail the first tie rod may be locked and the second tie rod is released, to couple the motor to the vehicle frame whereas when travelling on a curved rail the first tie rod may be released and the second tie rod locked to couple the motor for transverse movement with the bogie.

2. Atraction vehicle as claimed in Claim 1, in which the motor-gear unit assembly is suspended on the vehicle frame by three swing arms.

3. Atraction vehicle as claimed in Claim 2, in which a swing arm at the axle end and a swing arm at the motor end are connected together by a torsion bar, so that they allow only movement of the motor-gear unit assembly which is transverse to the direction of travel.

4. A traction vehicle as claimed in Claim 2 or 3, in which the transverse tie rods are pivoted to a swing arm at the axle end.

5. A traction vehicle as claimed in Claim 1, in which the motor-gear unit assembly is suspended on the bogie frame by two swing arms at the axle end, and on the vehicle frame by a swivel joint at the motor end.

6. Atraction vehicle as claimed in Claim 5, in which the swivel joint is fixed on the vehicle frame in the direct vicinity of the swivel pin of the bogie frame.

7. A traction vehicle as claimed in Claim 5 or 6, in which the swivel joint is fixed on the vehicle frame, by means of the swivel pin (5) of the bogie frame.

8. A traction vehicle a claimed in at least one of Claims 5 to 7, in which lockage coupling elements are disposed in the transverse tie rods.

9. Atraction vehicle as claimed in Claim 8, in which the coupling elements are mechanically lockable.

10. A traction vehicle as claimed in Claim 8, in which the coupling elements are electromechanically lockable.

11. A traction vehicle as claimed in Claim 8, in which the coupling elements are hydraulically or pneumatically lockable.

12. A traction vehicle as claimed in at least one of Claims 1 to 11, in which the locking of the coupling elements is effected in dependence upon the amplitude of transverse movement of the driving wheel set.

13. A traction vehicle as claimed in at least one of Claims 1 to 12, in which the locking of the coupling elements is effected in dependence upon the transverse force or on the amplitude of the relative movement between the motor-gear unit assembly and the bogie frame.

14. A traction vehicle as claimed in at least one of Claims 1 to 13, in which the Cardan shaft is a hollow shaft disposed concentrically to the wheel axle.

15. Atraction vehicle as claimed in at least one of Claims 1 to 14, in which vibration-damping devices are disposed between the motor-gear unit assembly and the bogie frame and/or the vehicle frame.

16. A traction vehicle as claimed in Claim 15, in which the lockable coupling elements additionally serve as vibration dampers.

17. Atraction vehicle substantially as herein described with reference to and as illustrated in Figure 1 or Figure 2 of the accompanying drawings.