EP2552761B1 - Rail vehicle with variable axel geometry - Google Patents

Description

Rail vehicle with variable axle geometry.

Technical field

The invention relates to a rail vehicle with variable axle geometry.

State of the art

The forces required for tracking arise in the contact area of the wheel and rail, the wheel-rail contact. However, these forces are also responsible for negative effects on the rails and wheels. Tangential forces, which are always associated with sliding effects and thus with friction, cause profile wear due to material removal. Furthermore, the forces acting on the wheel and rail tire the material if the force level is high enough, resulting in rolling contact fatigue (RCF). This creates, for example, fine cracks in the rail and / or in the wheel. Head checks represent a typical form of damage caused on the rail surface. Cracks can occur in the wheel under the surface, grow outwards and lead to larger crumbling. However, the cracks can also appear on the surface, grow deeper and also lead to material breakouts, as happens, for example, with the well-known phenomenon of the herringbone pattern. In the case of surface-initiated cracks, there is the effect that the cracks are partly removed again by the profile wear mentioned, from which it follows that a certain amount of profile wear is sometimes desirable can. In addition to the tread damage mentioned, a number of other types of damage occur, such as flat spots, material application, tread tears, etc.

The wheel-rail contact is therefore of particular importance in terms of safety, for example also for high-speed trains. Irregularities in the wheel-rail contact, for example due to severe damage to a wheel, can lead to considerable consequential damage and even derailment. Even slight damage such as fine cracks can cause great difficulties because they require maintenance work and can therefore cause high costs and delays in train traffic.

A number of mechanical devices for tracking a rail vehicle are therefore known. Many of the known systems assume that the radial position of the wheels in the track is optimal when traveling through bends in order to reduce the forces acting on the idler gear sets or gear sets of a chassis or vehicle. It is argued that the friction and thus the profile wear in the wheel-rail contact can be reduced.

For example, the EP 0 600 172 A1 a chassis for rail vehicles, in which the wheel sets are turned against the bogie frame by means of force-controlled actuators during bends. However, no radial position of the wheel sets relative to the track is realized, only the angle between the wheel set and undercarriage frame is set according to the radial position. Although this results in favorable wear behavior in many operating conditions, this does not correspond to the optimum.

The DE 44 13 805 A1 discloses a self-steering three-axle drive for a rail vehicle, in which the outer two wheel sets are provided with a radial control and the inner wheel set is movable transversely to the direction of travel by an active actuator. This reduces the lateral forces on the outer wheel sets - with a suitable action on the active actuator, one third of the centrifugal force acts on each wheel set. This means that all three wheel sets are used for steering when cornering, and the alignment of the wheel sets to the center of the curve is improved.

Another method of this type can be found in the EP 1 609 691 A1 the applicant.

All of these methods have in common that they aim to minimize the friction in the wheel-rail contact and thus the profile wear. With these methods, the position of the wheels relative to the track is influenced in such a way that sliding effects at the contact point are avoided or minimized. However, rolling contact fatigue also results in damage to the rail and wheel. To remedy this damage, a certain amount of friction can be desirable, as cracks in the material can be removed from the surface. A minimum of frictional power therefore does not always correspond to an optimal load ratio in the wheel-rail contact.

From the not previously published application A942 / 2007 "Method for minimizing tread damage and profile wear of wheels of a rail vehicle" by the applicant at the Austrian Patent Office is a model-based method for optimizing the Wear behavior of rail vehicle wheels known. In this method, the tread wear is optimized by means of actuator-controlled displacement (transverse displacement of the idler or axles or angular displacement between the axles) on the basis of determined measured variables.
Various chassis geometries are provided, which enable the axes to be shifted angularly and transversely. The so-called transverse actuators required for this make the construction of the chassis extremely difficult.

Presentation of the invention

The invention is therefore based on the object of specifying a rail vehicle with variable axle geometry, which can set any desired positions (angular position and transverse displacement) of the axles relative to one another while the rail vehicle is traveling, and the actuator effort required for this is minimized.

The object is achieved by a rail vehicle with the features of claim 1 and a bogie with the features of claim 6. Advantageous embodiments of the invention are the subject of dependent claims.

According to the basic idea of the invention, each axis of a rail vehicle is horizontally displaceable relative to the vehicle frame and can be changed continuously and independently of the other axes in its horizontal angular position by means of an associated actuator during the operation of the rail vehicle The angular position of each axis is specified by an optimization process.

The rail vehicle according to the invention or the bogie according to the invention are particularly advantageously suitable for implementing the method for optimizing the wear behavior described in the unpublished application A942 / 2007, since the design effort is greatly simplified by the present invention. The elimination of a so-called "transverse actuator", which is extremely complex in terms of design, is particularly important. Likewise, the present invention enables the use of structurally simple actuators (for example hydraulic or pneumatic cylinders or electrical actuators). The method described in A942 / 2007 provides the angular position between two axes and the so-called transverse displacement as output variables. These two sizes can be set with a rail vehicle according to the present invention only by setting certain horizontal angles of the axes to the vehicle frame, whereby smooth running of the rail vehicle and optimized wear behavior of the wheels is achieved.

The present invention achieves the advantage that optimum values for the angular position and transverse displacement can be set, only the horizontal angle of each axis to the vehicle frame being provided as variable. In particular, the present invention makes it possible to dispense with the structurally very complex transverse actuators.
The so-called asymmetrical control according to the invention makes it possible by means of the asymmetrical distribution of the angle da between two axes on two different ones Angle α1 and α2 to make the specific adjustment of the transverse displacement without having to provide an actuator for the transverse displacement.

A preferred embodiment of the invention provides for a fixed point (vertical pivot point) of each axis to be provided at one end of the axis and to assign an actuator which acts on the other end of the axis. According to the invention, this actuator is mounted on one side at a fixed point on the vehicle frame and on a second side on the horizontally angularly displaceable mounting of the associated axle of the rail vehicle. It is thus possible to achieve any desired horizontal angular positions of each axis by modulating the length of the actuator.

A further preferred embodiment of the invention provides that the actuators assigned to them act alternately on opposite ends of the axles on successive axles, so that, for example, on an axle whose actuator is arranged on one side of the rail vehicle, an axle whose actuator is on the opposite side of the Rail vehicle is arranged follows. This provides the advantage of being able to make optimal use of the space available in the chassis of the rail vehicle.
Other embodiments, in which, for example, the actuators of all axes are provided on one side of the rail vehicle, are also conceivable.

A special embodiment of the invention provides that the axles of the rail vehicle as a so-called "idler gear set" in which the wheels are mounted on a shaft (axle) and can rotate independently of one another.

Another embodiment of the invention provides the use of so-called "wheel sets", in which the wheels are firmly connected to the axle.

The invention is well suited for use in a bogie of a rail vehicle.

Brief description of the drawings

• Fig.1 ein Schienenfahrzeug mit variabler Achsgeometrie.
• Fig.2 die Ausgangsgrößen eines modellbasierenden Verfahrens zur Minimierung von Laufflächenschäden und Profilverschleiß.
• Fig.3 Bestimmung der horizontalen Winkel jeder Achse.
• Fig.4 Bestimmung der Auslenkung von Aktuatoren.

The following are examples:

• Fig. 1 a rail vehicle with variable axle geometry.
• Fig. 2 the output variables of a model-based process for minimizing tread damage and tread wear.
• Fig. 3 Determination of the horizontal angle of each axis.
• Fig. 4 Determination of the deflection of actuators.

Implementation of the invention

Fig. 1 shows an example and schematic of the basic structure of a rail vehicle with variable axle geometry. A rail vehicle S comprising two axles A1, A1 which are horizontally rotatably supported about a pivot point at one end of each axis A1, A2. On the side of each axis A1, A2 opposite the pivot point, an actuator AKT1, AKT2 acts on the end of each axis A1, A2, which is connected at its other end to the frame of the rail vehicle S. By modulating the length of the actuators AKT1, AKT2, a specific horizontal angle α1, α2 can thus be set for each axis A1, A2. Are for successive axes different horizontal angles α1, α2 are set, this results in a transverse displacement dy and an axis angle da of α1 + α2 between these axes. It can be seen that in addition to the axle angle, the transverse displacement dy has a decisive influence on the wear or damage behavior of the vehicle.

This transverse displacement dy is geometrically defined in that the normals N1, N2 do not meet the center points of the wheel axles in the plane of symmetry S of the bogie, but have a distance in this plane of symmetry S.

According to the invention, the transverse displacement dy is achieved together with the radial position of the axes by the specific setting of the axis angles α1, α2 of the axes. This provides a simple and reliable possibility of adjusting the transverse displacement dy with little effort on actuators.

Fig. 2 shows an example and schematically the output variables of a model-based method for minimizing tread damage and tread wear.
A rail vehicle with two axes A1 and A2 is shown, which can assume any horizontal angular positions (axis angle da) with respect to one another and which have a transverse displacement dy with respect to one another. The center distance L corresponds to the distance between the centers of the axes A1 and A2. The effective center distance can approximately be equated to the center distance L, since usually only very small axis angles occur. The two sizes axis angle there and Transverse displacement dy are determined using a model-based method so that, among other things, optimal wear behavior of the wheels and rail profiles is achieved.

Fig. 3 shows, by way of example and schematically, the determination of the horizontal angles of each axis, the combination of the horizontal angle of the first axis α1 and the horizontal angle of the second axis α2 being determined from the predetermined values of the axis angle da and transverse displacement dy.

und $$\mathit{dy}=\frac{L}{2}\left(\sin \alpha 2-\sin \alpha 1\right)$$

für kleine Winkel näherungsweise $$\mathit{dy}=\frac{L}{2}\left(\alpha 2-\alpha 1\right)$$

bestimmen sich der horizontale Winkel der ersten Achse α1: $$\Rightarrow \alpha 1=\frac{\mathit{d\alpha }}{2}-\frac{\mathit{dy}}{L}$$

und der horizontale Winkel der zweiten Achse α2: $$\Rightarrow \alpha 2=\frac{\mathit{d\alpha }}{2}+\frac{\mathit{dy}}{L}$$

From relationships $$\alpha 1+\alpha \mathrm{2nd}=\mathit{d\alpha }$$

and $$\mathit{dy}=\frac{L}{\mathrm{2nd}}\left(\sin \alpha \mathrm{2nd}-\mathrm{<figure-callout\; id="1"\; label="sin\; \alpha "\; filenames="imgf0001.png"\; state="\{\{state\}\}">sin\; </figure-callout>}\alpha 1\right)$$

approximately for small angles $$\mathit{dy}=\frac{L}{\mathrm{2nd}}\left(\alpha \mathrm{2nd}-\mathrm{<figure-callout\; id="1"\; label="\alpha "\; filenames="imgf0001.png"\; state="\{\{state\}\}">\alpha </figure-callout>}1\right)$$

the horizontal angle of the first axis α1 is determined: $$\Rightarrow \alpha 1=\frac{\mathit{d\alpha }}{\mathrm{2nd}}-\frac{\mathit{dy}}{L}$$

and the horizontal angle of the second axis α2: $$\Rightarrow \alpha \mathrm{2nd}=\frac{\mathit{d\alpha }}{\mathrm{2nd}}+\frac{\mathit{dy}}{L}$$

und $$s2=A\cdot \tan \alpha 2$$

ermittelt werden. Fig. 4 shows an example and schematically the determination of the deflection of actuators in a rail vehicle according to Fig1 . This in Fig. 1 The rail vehicle shown is equipped on each of the axes A1, A2 with an actuator AKT1, AKT2, which acts on the end of each axis A1, A2. From the according Fig. 3 certain individual angles .alpha.1 and .alpha.2 can determine the required deflection of each actuator in accordance with: $$s1=A\cdot \mathrm{<figure-callout\; id="1"\; label="tan\; \alpha "\; filenames="imgf0001.png"\; state="\{\{state\}\}">tan\; </figure-callout>}\alpha 1$$

and $$s\mathrm{2nd}=A\cdot \tan \alpha \mathrm{2nd}$$

be determined.

List of names

S

Rail vehicle

A1

first axis

A2

second axis

ACT

Actuator

ACT1

First axis actuator

ACT2

Second axis actuator

α

horizontal angle

α1

horizontal angle of the first axis

α2

horizontal angle of the second axis

dα

Axis angle

dy

Transverse displacement

L

Wheelbase

A

Axis length

S1

Deflection of the actuator of the first axis

S2

Deflection of the actuator of the second axis

Claims (10)

1. Rail vehicle (S) with variable axle geometry with at least two axles (A1, A2), wherein the horizontal angular position (α) of each axle is able to be changed in relation to the vehicle frame, characterised in that the angular position (α) of each axle is continuously adjusted by actuators during the operation of the rail vehicle so that a predetermined lateral displacement (dy) and a predetermined axle angle (dα) are achieved, wherein a space between centre points of the axles (A1) and (A2) corresponds to an axle distance (L), an angle of a first axle (α1) is determined from a relationship $\alpha 1=\frac{d\mathrm{\alpha }}{2}-\frac{\mathit{dy}}{L}$

   

   and an angle of a second axle (α2) is determined from a relationship $\alpha 2=\frac{d\mathrm{\alpha }}{2}+$

   

   $\frac{\mathit{dy}}{L}$

   
2. Rail vehicle (S) with variable axle geometry according to claim 1, characterised in that the lateral displacement (dy) and the axle angle (dα) are determined by means of a model-based method.
3. Rail vehicle (S) with variable axle geometry according to claim 1 or 2, characterised in that the axles are embodied as wheel sets with independent wheels.
4. Rail vehicle (S) with variable axle geometry according to claim 1 or 2, characterised in that the axles are embodied as wheel sets.
5. Rail vehicle (S) with variable axle geometry according to claim 1 or 2, characterised in that the actuators (AKT) of two consecutive axles (A1, A2) are attached to respective opposite sides of the axles.
6. Bogie with variable axle geometry for rail vehicles (S) with at least two axles (A1, A2), wherein the horizontal angular position (α) of each axle is able to be changed in relation to the bogie frame, characterised in that the angular position of each axle is adjusted continuously by actuators during the operation of the rail vehicle so that a predetermined lateral displacement (dy) and a predetermined axle angle (dα) are obtained as in claim 1.
7. Bogie with variable axle geometry according to claim 6, characterised in that the lateral displacement (dy) and the axle angle (dα) are determined by means of a model-based method.
8. Bogie with variable axle geometry according to claim 6 or 7, characterised in that the axles are embodied as wheel sets with independent wheels.
9. Bogie with variable axle geometry according to claim 6 or 7, characterised in that the axles are embodied as wheel sets.
10. Bogie with variable axle geometry according to claim 6 or 7, characterised in that the actuators (AKT) of two consecutive axles (A1, A2) are attached to the respective opposite sides of the axles.

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