EP0765791B1 - Single axle running gear box for a railway vehicle - Google Patents

Abstract

The chassis has the individual wheel set supported by a chassis frame (50) acted on by a spring elastic device (6), providing a restoring force opposing the movement of the chassis frame when travelling around a curved track section. The chassis frame is attached to a yoke (58) via linkages (61,61') allowing its movement relative to the yoke in both vertical and transverse directions, with impact buffers (68,68') limiting the transverse movement.

Description

The invention relates to a single-axle running gear for a rail vehicle according to the preamble of claim 1.

Such a single-axle chassis is already known from EP-A-282738 and can be compared to bogie drives, where at least two wheel sets are provided per bogie, lead to a saving of axles or a reduction in costs.

The object of the invention is an improved single-axle chassis to provide.

According to the invention, this is achieved with a single-axle chassis of the type mentioned at the beginning by the features specified in the characterizing part of claim 1.

In one of the preferred exemplary embodiments of the invention, force-controlled actuators are used Generation of a counterforce acting against the restoring force and a force magnitude provided on the force-controlled actuator adjusting control, wherein the force set on the actuator depends on the radius of the track curve.

It is known that a wheel set of a rail vehicle that has a corresponding profile the wheel tread has an independent when cornering on a curved track Can perform steering movement around a vertical axis. For example tapered profile of the tread results in a curved track Roll radius difference between the inner and outer running circle, resulting in a radial adjustment movement of the wheelset is caused.

For a favorable wear behavior, the lowest possible contact angle between the wheel and rail desirable. For this purpose, the wheelset should move freely be restricted as little as possible around the vertical axis. At one in This type of wheel set, which is softly coupled to the vehicle, occurs when running in a straight line Sine or wave running, which is inherently harmless. From a certain speed However, the sinus run suddenly hits the dangerous and weary zigzag run around. This speed limit is called the critical speed, she largely determines the maximum permissible speed of the vehicle.

In order to counteract the zigzag run and to reach a high limit speed, is therefore known to be a device for generating a restoring force against a radial rotation of the wheelset is used. For example, the Restoring force by at least one elastically resilient element acting on the wheelset exercised.

When designing trolleys that are suitable for both high speeds, and also have good sheet running properties (low wear) Now the following contradictory situation: For good sheet running properties with The wheelset should be coupled to the vehicle with little wear, i.e. the The restoring force is low, whereas high speeds require a large one Restoring force.

A known approach provides that the steering deflection of the wheelset by Priority control is set, i.e. through a mechanical coupling of the steering deflection of the wheel set with another depending on the radius of the curve mechanical size. This size is e.g. the deflection angle between one Storage of two wheelsets serving bogies and the body. The The turning angle of the wheelset is not determined by the between the wheel and the rail occurring forces, but mechanically due to purely geometric conditions generated.

This solution has two major disadvantages:
On the one hand, very high setting accuracies are required for the mechanical coupling, which can only be achieved with great effort during operation, on the other hand, bogie bends in a straight line can cause unwanted wheel set deflections and unstable running (zigzag running) due to track position problems.

By using a force-controlled actuator, the restoring force of the Resilient device can be set high, providing the desired stability the vehicle run is reached with a high limit speed. At a Cornering is done via the force-controlled actuator depending on the radius of the Track arch exerted a counterforce acting against the restoring force. Achieved by this one has a pre-tax effect of the wheelset. However, this does not mean forced control, because the angular position of the wheel set, which is precisely adapted to the track curve, continues to be correct the forces occurring between wheel and rail are adjusted independently. The The result is a very small run-up angle between the wheel and rail and therefore a excellent wear behavior.

As a force-controlled actuator, for example, at least one proportional one Pressure control valve, a proportional pressure relief valve or a pressure controlled pump be used. To avoid instabilities with small deflections in straight running avoid, the counterforce acting against the restoring force is preferably only from a certain threshold of the detected radius of the arc.

It is also conceivable to adjust the speed of the force increase by a suitable one Limit the switching so that rapid changes in the manipulated variable (e.g. Turning angle of the bogie) not to the same extent on the steering movements of the Wheelset act, but the wheelset steering movements take place more slowly.

Abb. 1 eine schematische Darstellung einer möglichen Steuerung des kraftgeregelten Stellgliedes bei zwei an einem Drehgestell gelagerten Radsätzen mit Hilfe einer Einrichtung zur Erzeugung einer Gegenkraft und einer elektrohydraulischen Regeleinrichtung; Abb. 2 ein zweites Ausführungsbeispiel der elektrohydraulischen Regeleinrichtung; Abb. 3 ein Diagramm der Kennlinie der auf den Radsatz wirkenden Rückstellkraft ohne (a) und in Kombination mit der Gegenkraft (b); Abb. 4 zu einer baulichen Einheit zusammengefaßte Einrichtungen zur Erzeugung der Rückstellkraft, sowie zur Erzeugung der Gegenkraft; Abb. 5 eine schematische Darstellung eines einzeln aufgehängten Radsatzes; Abb. 6 eine Draufsicht auf ein erfindungsgemäßes Einzelachslaufwerk; Abb 7 die Ansicht des Fahrwerkes aus Abb. 6 von vorne; Abb. 8 dessen Seitenansicht; Abb. 9 eine schematische Abbildung eines Zentrierfederelementes und Abb. 10 dessen Kraft-Weg-Kennlinie.

Further details of the device according to the invention are then discussed with reference to the drawings. In these is:

Fig. 1 is a schematic representation of a possible control of the force-controlled actuator in two wheel sets mounted on a bogie with the help of a device for generating a counterforce and an electro-hydraulic control device; Fig. 2 shows a second embodiment of the electro-hydraulic control device; Fig. 3 is a diagram of the characteristic curve of the restoring force acting on the wheelset without (a) and in combination with the counterforce (b); Fig. 4 devices combined to form a structural unit for generating the restoring force and for generating the counterforce; Fig. 5 is a schematic representation of an individually suspended wheelset; Fig. 6 is a plan view of a single-axis drive according to the invention; Fig. 7 the view of the chassis from Fig. 6 from the front; Fig. 8 its side view; Fig. 9 is a schematic illustration of a centering spring element and Fig. 10 the force-displacement characteristic.

In Fig. 1 two wheel sets 1, 1 'rotatable about a vertical axis are shown which are connected to the both ends of a bogie 8 also rotatable about a vertical axis are. The wheel sets 1, 1 'consist of the axles 2, the axle bearings 3 and the wheels 4, whose treads 5 are provided with a conical profile, which during an arc ride leads to the self-tax effect described. The wheel sets 1, 1 'are one Angle β deflected or their axle bearings 3 shifted by a distance S.

Resilient elements, for example springs 6, act on the axle bearings 3 Exercise restoring force, which acts against a deflection β of the wheel sets. By means of the force-controlled actuators 7 can a counterforce acting against the restoring force be exercised.

The electro-hydraulic control device 20 consists of a hydraulic fluid reservoir 21, a pump 22, a pressure return 23, a throttle 24 and two electronically controlled proportional pressure regulating valves 12, 13, the outlet side of which Pressure is set in each case by a voltage that the control device 11 outputs.

When traveling on a curved track, the bogie 2 rotates relative to that Car body (not shown) at an angle  that is proportional to the curvature of the Track arc is. With the help of a transducer 10, which in this embodiment in essentially contains a potentiometer, the deflection angle  of the bogie is in a control voltage U implemented. The amount of this tension is proportional to Deflection angle  (and thus to the curvature of the track arch) and its sign depends on the direction of rotation.

Threshold elements 30, 31 subsequently check the magnitude and the sign of the voltage U. If U is above a certain threshold value U _o , the voltage U is switched through to the output of the threshold element 30. It is then amplified by the amplifier 32 and used to control the pressure control valve 12. As a result, the pistons of the cylinders 7 are acted upon by a pressure proportional to U via the hydraulic line 40.

In the opposite case, when U is below a threshold value -U _o , the pressure control valve 13 is controlled via the amplifier 33, whereby the pistons of the cylinders 7 are acted upon by a pressure proportional to U via the hydraulic line 41.

The pressure on the pistons of the cylinder 7 is always exerted in such a way that a Force acts against the restoring force of the springs. In the case of the one shown in Fig. 1 Deflection of the bogie in a clockwise direction will change the upper wheelset adjust certain angle β clockwise. The springs 6 exercise against them Deflection a restoring force. To apply a force against the restoring force, the left piston of the upper wheel set must be on its axis away, the right one on its a corresponding pressure is applied to the side near the axis.

If U is in the range between -U _o and U _o , both outputs of the threshold members 30, 31 are de-energized and the outputs of the pressure control valves are depressurized, so that no force is exerted on the pistons of the cylinders 7. This ensures stable straight running, even if there are small deflections of the bogie. If the outputs of the two threshold elements 30, 31 are de-energized, this also applies to the output of the OR gate 34. A switching element 35 then switches off the pump motor 22a after a predetermined time delay via a switch 36. The pump 22 thus only works when cornering.

An alternative embodiment of the electro-hydraulic control device 20 is shown in Fig. 2. The control voltage U controls two electronically controlled proportional pressure relief valves 112, 113 from the Mannesmann Rexroth company, type DBETE St / 200 624. In this case, only one inverter 111 is required to control the valves, which reverses the sign of the control voltage for the valve 113. The valves 112, 113 only respond to positive values of U, whereby the hydraulic line 140 or 141 to be pressurized is selected in connection with the inverter 111. The valves 112, 113 also have a setting for specifying a threshold value U _o for the voltage U, below which no pressure is exerted on the pistons. There is also the option of specifying a limit for the maximum rate of increase in pressure. This embodiment has the advantage over the control device from FIG. 1 that, with a control voltage U <U _o, no pressure is built up in the pump circuit, so that the pump can operate in an energetically favorable manner in idle mode.

The operation of the force-controlled actuators can be explained most easily with the help of Fig. 3. In Fig. 3a the dependence of the restoring force on the axle bearing displacement s (see Fig. 1) is a straight line F x = cS marked with c the spring constant. The adhesion limit F _G between rail and wheels indicates the maximum size of the radial adjustment force due to the self-steering effect. The intersection of F _x and F _G determines the maximum axle bearing displacement S _m in a conventional axle control, which can be achieved during an arc travel against the restoring force. The ideal axle bearing displacement, in which the steering deflection of the wheel set is optimally adapted to the radius of the track curve, can, however, be at a larger value S _i . Especially with hard springs with a large spring constant c, which allow high limit speeds, the track radius S _{m is} far below S _i with a small radius, so that a large run-up angle between wheel and rail results in unfavorable wear behavior.

Fig. 3b shows the situation with additionally used force-controlled actuators. The counterforce against the restoring force can be represented as a downward shift of the straight line F _x by a value F _y . F _y corresponds to the force applied to the cylinders 7 (see Fig. 1). The size of F _y is chosen so that the shifted straight line F _x 'intersects the x-axis approximately at S _i . However, F _y does not have to be set very precisely, but can lie in a relatively large range, which is given by the fact that the intersection of F _x 'with the x-axis lies within the free adjustment range FE between S _i -S _m and S _i + S _m lies within which the wheelset can adjust itself automatically to the optimal steering deflection S _i .

Since S _{i is} proportional to the curvature of the track curve, F _y must also be approximately proportional to the curvature of the track curve, so that the x-axis intersection of F _x lies between S _i -S _m and S _i + S _m for each curve of the track curve. To determine the proportionality constant of F _y , the spring constant c of the return spring is taken into account.

Another possible embodiment of the force-controlled actuators is shown in Fig. 4 shown. In this are the devices for generating the restoring force and for generating the opposing force combined into a structural unit. To do this, a hydraulic or pneumatic piston 70 against the cylinder 71 in which it is guided, elastically clamped, for example in the manner shown with a spring 72 Hydraulic lines 73, 74, the cylinder with a deflection of the spring with a pressure against the force of the spring.

Two wheel sets are not required to use force-controlled actuators be stored together on a bogie. As shown in Fig. 5, is also at individually, for example in a bogie, mounted wheel sets 1 the attachment of force-controlled actuators 7 possible, which have a counterforce against the restoring force of exercise resilient elements 6. The device for recording the radius of the track curve in this case, of course, cannot take advantage of the deflection angle of a bogie, but has to work in a different way. For example, the angle between Use two car bodies to record the radius of the track curve. Furthermore are too auxiliary wheels or optical devices conceivable and possible for this purpose. This alternative devices for the detection of the curve radius can of course also with wheelsets mounted on a bogie can be used. It is also conceivable and possible, even for individually stored wheels facilities for exercising Restoring force and a counterforce against the restoring force in an analogous manner as in To attach wheel sets.

All conceivable resilient devices can be used to exert the restoring force are used, such as rubber bellows or pneumatic springs. To exercise All force-generating elements, essentially one, come into consideration for the counterforce Generate location-independent force, for example hydraulic cylinders, pneumatic cylinders or Air bellows.

A single-axis drive according to the invention with one individually in a chassis frame 50 guided wheel set 51 is shown in Figs. 6-8. The wheelset 51 can thereby a motor 52 can be driven via a gear 53 and a clutch 54. The wheels 59, 59 'of the wheelset 51 are rigidly connected to one another via a wheelset shaft 65. The The wheelset 51 is supported in the axle bearings 55 (see Fig. 8), which have a Primary suspension 56 are connected to the chassis frame 50. The chassis frame 50 is with a secondary suspension, which is formed by air springs 57 Car body 60 connected. Furthermore, the chassis frame 50 is articulated with a Guide cross member or a yoke 58 connected. This connection is now made according to the invention by two Handlebar pairs 61 and 61 'made, which are rotatable about vertical axes and which are articulated on the one hand on the chassis frame 50 and on the other hand on the yoke 58. The elongated longitudinal axes 91, 91 'of the links 61, 61' intersect seen in plan view in the area of the longitudinal axis 92 of the wheel set 51, specifically in the area of the center line 93. The yoke 58 in turn is articulated via trailing arms 62, 62 'with guide brackets fixed to the carriage 63, 63 'connected. If the joints of the trailing arms 62, 62 'thereby Ball joints are formed, displacements of the guide cross member 58 are opposite The body is not only possible in the horizontal, but also in the vertical direction.

Because of the articulated connection of the chassis frame 50 with the guide cross member 58 and due to the elasticity of the air springs 57 are steering movements of the Chassis frame 50 possible about a vertical axis. The primary suspension between Wheelset 51 and chassis frame 50, however, has such a hard in the longitudinal direction Spring constant on that almost no steering movements of the gear set 51 compared the chassis frame 50 are possible. Against those when driving over a railway arch due to the difference in the wheel radius of the wheels 59, 59 'caused the steering movement of the Chassis frame 50 acts the restoring force of the spring-elastic element 6, which engages on the one hand on the chassis frame 50 and on the other hand on the yoke 58 and transversely to Direction of travel is arranged. To apply an anti-resetting force A force-controlled actuator 7 is provided against the counterforce. With this, in turn, how Force feedforward has already been carried out with reference to FIG. 3 become, d. H. the characteristic curve of the spring-elastic element 6 is shifted during an arc travel, whereby an optimized driving behavior of the chassis is achieved.

When accelerating and braking, longitudinal forces are exerted on the chassis by the trailing arms 62, 62 'can be added. There is also a pitch support 69 provided that a rotation of the chassis frame 50 about a transverse axis prevented. An anti-roll support, not shown, can also be provided in an analogous manner be, which prevents rotation of the chassis frame 50 about a longitudinal axis. Cross movements of the undercarriage frame 50 are fixed to the carriage Guide brackets 63, 63 'attached transverse stop buffers 68, 68' limited or cushioned.

The resilient element 6 is advantageously formed by a centering spring element, shown in Fig. 9. This has a housing 80 with stops 80a fixed to the housing, against which stop rings 83 rest in the idle state. Between the stop rings 83 a spring 81 is placed under prestress. The rod 84 passing through the housing 80 has two flanges 85 within the housing 80 at a distance from the stops 80a of the housing 80, between which the stop rings 83 lie. The behavior of the centering spring element in the event of a force exerted on the rod 84 is described by the characteristic curve shown in FIG. 10. With a force that is below a certain threshold value F _s , there is no displacement of the rod 84, since the spring 81 is under a prestress. Only when the force is above the threshold value F _s is there a displacement of the rod 84, the rod 84 again returning to the centered starting position after the force has been exerted. By using such a centering spring element, the chassis frame can be centered with only a single spring element 6 and the characteristic curve of the centering spring element shown in FIG. 10 leads to an improvement in the stability of the drive according to the invention when driving straight ahead.

In practice, it happens especially in narrow track bends that the rails are so are worn out that the roller radius difference and thus that acting on the wheelset radial setting force are significantly changed compared to unworn rails. Furthermore There may be a change in the frictional resistance of the force-controlled over time Control element 7 come. To reliably be an ideal despite these effects Reaching the radial position of the wheelset could therefore, as shown in Fig. 6, be a Sensor 67, for example an inductive displacement sensor, can be provided which detects the actual value of Steering deflection recorded. In a control loop, this actual value could subsequently be compared to that in Dependent on the radius of the track curve, the desired value of the radial setting of the Wheelset 51 are compared and in the event of a deviation that of the power-controlled Actuating counterforce exerted until the setpoint is reached. Around This control mechanism has no rocking movements of the undercarriage a conveniently large compared to the sinusoidal frequency of the wheelset Time constant. A sensor 67 could also detect a malfunction, can be used for example in the hydraulic system.

The single-axle drive shown in Fig. 6 - 8 is extremely comfortable to drive, because it perfectly fulfills the diverse requirements for a drive. Even if the Hydraulics is guaranteed safety due to the self-centering of the wheelset 51 by means of the spring element 6. An advantage over conventional Bogie bogies is the possible saving on axles, resulting in a Cost reduction leads.

Claims (7)

1. A single-axle bogie for a rail vehicle in which a single wheel assembly (51) whose wheels (59, 59') are rigidly connected by way of a wheel assembly shaft is guided in a bogie frame (50), wherein there is provided a resilient device (6) for producing a return force against the steering deflection of the bogie frame (50) which occurs when negotiating a curve in the track, having a yoke (58) which on the one hand is hingedly connected to the railway car body and is displaceable with respect to the railway car body in a vertical direction and in a transverse direction and to which on the other hand the bogie frame (50) is vertically steerably connected, characterised in that there are provided links (61, 61') which are mounted to the yoke (58) and to the bogie frame (50) rotatably about vertical axes and whose notional extended longitudinal axes (91, 91'), as viewed in plan, intersect in the region of the longitudinal axis (92) of the wheel assembly (50) in the region of its centre line (93) (Figure 6).
2. A single-axle bogie according to claim 1 characterised in that the yoke (58) is hingedly connected to the railway car body (60) by way of longitudinal links (62, 62') for carrying the longitudinal forces which occur.
3. A single-axle bogie according to claim 2 characterised in that the longitudinal links (62, 62') are mounted in the yoke (58) and in the railway car body (60) by means of ball joints.
4. A single-axle bogie according to one of claims 1 to 3 characterised in that the movement of the bogie frame (50) in the transverse direction is limited by transverse stop buffers (68, 68') which are arranged on guide brackets (63, 63') which are fixed with respect to the railway car.
5. A single-axle bogie according to one of claims 1 to 4 characterised in that there are provided a power-regulated actuator (7) for producing a counteracting force which acts against the return force and a control or regulating device for setting the magnitude of the power at the power-regulated actuator (7), wherein the magnitude of the power set at the actuator (7) is dependent on the radius of the curve in the track.
6. A single-axle bogie according to claim 5 characterised in that the resilient device (6) for producing the return force and the power-regulated actuator (7) for producing the counteracting force engage on the one hand the bogie frame (50) and on the other hand the yoke (58).
7. A single-axle bogie according to one of claims 1 to 6 characterised in that there are provided a sensor (67) for detecting the actual value of steering deflection and a regulating circuit for re-adjusting the magnitude of the power at the power-regulated actuator (7) in the event of a deviation of the reference value of steering deflection from the actual value.

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