Means for counteracting slipping and skidding in a motor-driven rail-vehicle

© Start of patent duration: 1976 06 15 Longest possible duration:

© Issued on: 1977 02 25 © inventor:

© dependence:

OE 335016 © Publications that have been considered as delimiting from the state of the art:

DT-OS1413701, DT-OS1513642, DT-GS1580932, GB-PS1299731

No. 335016

The invention relates to an electric anti-skid device for motor-driven rail vehicles with a torque actuator, which can be acted upon in the occurrence of spin with a Eührungsgröße, at least one Schwellenwertsehalter emits a signal when exceeding or falling below a predeterminable value for the particle acceleration of the wheel.

In the context of locomotive operation with very high adhesion utilization, it is a major problem that one or more drive axles skid, either during acceleration or engine braking. As long as not all axles spin, the spin can be detected in a known manner - for example, by comparing the speeds of the axes with each other - and fixed. However, if all axes spin at the same time, you can not use the simple investigation method mentioned above. Certainly, the driver notes the spin, z. B. by means of the speedometer, and can reduce the torque manually, ie the tensile force or the braking force; however, before the leader has been able to accomplish this, the drive wheels could be accelerated to a very high speed or stalled during deceleration. It has been found that in the correction of such Sehleuderas (hard braking) can occur very large Zugkraftsvariationen, which sometimes cause high mechanical stresses in the motor vehicle itself and sometimes cause a serious risk that a drawn by a locomotive train is released because the clutch assemblies break.

It is an object of the invention to provide an arrangement for the elimination of Schleudems, which is applicable for avoiding high mechanical stresses in the traction unit for the simultaneous spinning all drive axles.

The solution of the problem is in the aforementioned device according to the invention in that between the output of a threshold switch and the torque actuator, a function generator is connected to an integrator in whose Riiekkopplungskreis another threshold switch, wherein the function of the torque sensor torque decrease in two linearly decreasing Steps takes place.

An embodiment of the invention will be described with reference to the drawings. Fig. 1 shows an arrangement according to the invention and Fig. 2 shows the time course in some present in the arrangement control variables.

Fig. 1 shows an electric drive arrangement for a locomotive. The DC motor -M-, whose armature is shown, drives one or more drive shafts, not shown, for example via gear transmission. The armature is supplied with DC power from a controllable power converter -SR- whose AC power supply -AC- is connected to an AC power supply. A setpoint I for the

Motor current is compared in comparison device -S2- with the actual value I of the motor current obtained from the current measuring device -IM-. The difference is fed to a current regulator -IR-, which controls the output voltage of the power converter so that I strives to match I.

Coupled to the motor or the drive wheel is a tachometer generator -TG- which outputs a signal proportional to the wheel speed n. From the potentiometer -PI- you get a setpoint for the speed. The difference between n and n ^ is obtained from comparator -SI- and this is fed to the speed controller -NR-. Its output signal makes the current reference in principle. This is fed to the comparator -S2- via two limiting amplifiers -BF1 and BF2-. Each of them has its limit input, -BH or BI2-.

The output signal from a limiting amplifier is in principle coincident with the input signal, but can not exceed the value supplied to the limiting input. From the potentiometer -P2- one obtains an adjustable value I which is fed to the limiting input of the amplifier max -BF1-. As a result, I and thus the acceleration of the vehicle is limited upward to an I corresponding value. The previously described part of the drive order is already known max.

According to FIG. 1, a differentiating element -DK- is connected with its input to the tachogenerator -TG-. The output of the differentiating gate is fed to a low pass filter -F- to reduce the influence of noise, noise, etc., and is fed to two threshold switches -NV1 and NV3-, ie bistable circuits having two stable values ​​of the output signal, a positive one and a negative one. Threshold switch -NV1- is arranged to switch from a negative to a positive output signal at a certain positive value of the input signal and to switch from a positive to a negative output signal at a decreasing input signal 55 at a lower absolute level of the input signal than that at the envelope turned into a positive output.

No. 335016

The threshold switch -NV1- is arranged to switch to a positive output signal dn at a value of - which is greater than that which can be obtained during a normal acceleration without

The spin is obtained and the threshold switch -NV3- is arranged in the same way to switch to a positive output signal at a value of - whose absolute value is greater than that obtained during normal braking. This Umhehlagniveau can be fixed or adjustable, depending on

Draw weight and possibly also the set maximum traction (braking force) I. The Schwellenmax value switches are arranged so that they switch to a negative output signal at a low absolute value of 77, possibly at 77 = O, dt dt

A positive output signal from the two threshold switches -NV1 or NV3- is sent via the

Diode -D1 or D3- and the resistor -RI- to the input of an inverting integrator -IN-, while a negative output signal from the two threshold switches -NV1 and NV3- of -Dl or D3- is disabled. The input of the integrator -IN- is supplied via the diode -D2- and the resistor -R2- the output signal from a threshold switch -NV2-. Its input signal is derived from the current reference I ".

ref

The threshold switch -NV2- operates in the same way as the threshold switch -NV1-. This suggests a positive output at a value of 1 ^ to z. B. may be about 75% of the maximum adjustable motor current, and he suggests a negative output at a

Value of I "um, which is so selected, for example, about 10% of the maximum adjustable motor current, ret that the spin is experienced normally corrected. The value of the resistor -R2- is greater than that of the resistor RI-, which is why with a positive output signal of NV1 or NV3 and negative output signal of -NV2- the output signal of -NV1 or NV3- will prevail.

Furthermore, to the input of the integrator -IN-, a negative DC voltage is connected across a resistor -R3-. This voltage and the value of -R3- are chosen so that the integrator, in the absence of other input signals, is controlled relatively slowly towards its end position, suitably the maximum motor current that can be set equivalent. The output signal from the integrator is fed to the limiting input -BI2- at the limiting amplifier -BF2- whose function has been described above.

In normal operation without skidding, the two threshold switches -NV1 and NV3- set negative output signals. The input signal to the integrator via -R3- keeps the output signal of the integrator -IN- in its positive end position and the limiting amplifier -BF2- therefore has no influence on the motor current. The threshold switch -NV2-, depending on the motor current, either a positive output signal, which is disabled by -D2-, or a negative output signal, which has no influence on the integrator -IN-, which is already in its positive end position.

Fig. 2 shows the function of an arrangement during spin during acceleration. Before time ίθ 1 ^ and thus the motor current has its maximum value. The train takes a constant speed change -7-, and the speed n rises slowly. The threshold switch -NV1- has a dt negative output signal, and the input signal a to the integrator -IN- is zero. The threshold switch -NV2- has a positive output signal and the input signal b is also zero. The output signal c of the integrator -IN- has its positive limit, which corresponds to the maximum motor current.

dn

At time ίθ, the wheels driven by the engine begin to skid - Qv is currently increasing to a high value. The threshold switch -NV1- beats to a positive output signal. The output signal c of the integrator IN starts to decrease relatively quickly with a speed determined inter alia by the said output signal and by -RI-. I "is thereby ref

Limiting amplifier -BF2- limited and fall in time with the signal c. If at t ^ 45 1 ^ has dropped to about 10% of the maximum motor current, the threshold switch -VV2- to a negative output signal.

This counteracts the positive signal of -NV1-, whereby c and I decrease more slowly. At ref at time t2, the acceleration of the drive wheel has dropped to the Umsehaltpegel (zero) of the threshold switch -NV1-. The signal a becomes zero and the negative signal b increases it

Output signal of the integrator with a certain speed, among others -R2-

No. 335016

- 4 and thus I "and the motor current. At tq, I "has become so high that the threshold switch ref ° ref -NV2- turns over and the signal b becomes zero.

The negative signal obtained via -R3- is now the only input signal to the integrator -IN-, and its output signal c will therefore, just like I, increase according to an exponential function with a relatively large time constant to a value corresponding to the maximum current. This smooth transition to maximum acceleration prevents the occurrence of a new spin as much as possible.

In the same way, the threshold value switch -NV3- intervenes during skidding as a result of incipient deceleration ens.

The time constants of the spinner assembly are, in a typical case, chosen so that the whole course now described takes a time of the order of 1 second. The maximum overspeed to which the drive wheels can accelerate is limited to approximately 10 km / h in a typical case. Partly one achieves thereby, that the loss of traction (at the speed of the rapid spin removal) becomes very small and partly that the initially mentioned violent traction variations and jerks in the wagon row are practically eliminated.

In cases where two or more motors each drive one drive axle and are fed by a common power converter, the axle drive on the different axes usually has different effects during acceleration. Experience has shown that one knows which axis normally flings first, and the speed response from this axis can then be used to control a skid guard assembly attached to the stream 20 according to the invention.

If, on the other hand, it is desirable for the control arrangement to respond only when all the axes are spinning, then the velocity response from the axis is used, which according to experience has recently flung. Alternatively, a selector switch may be arranged to select the magnitude of the velocity responses from the various axes, which is then fed to the control arrangement according to the invention. The control assembly will then intervene as soon as an axle begins to skid. A disadvantage with this is that one obtains in some cases unnecessary draw force reduction.

According to another embodiment, the selector switch may therefore be arranged to select the smallest of the speed responses. The system will intervene only if all axles connected to the same power converter fling, and according to this Aus30 design gives you a greater traction and thus a faster acceleration.

Of course, instead of the speed responses, the dialing circuit may be applied to the time derivatives of the various speed responses.

Of course, a vehicle may be provided with a plurality of power converters, each of which feeds one or more motors. In this case, each power converter is expediently provided with a Schleuderbe35 lifting system of the above type, Alternatively, the speed response of all engines or axles via a Wahlschaftung a single Sehleuderbehebungssystem be supplied, the output signal is then fed to all converters to limit their current.

The developments of the invention described in connection with the acceleration can also be applied to home brakes.

The control arrangement has been described above in the context of DC electric motors powered by controllable power converters. Of course, it can also be used in other types of electric motors and in other systems for measuring and tension regulation and also in other types of drive motors, as electric motors.

In the Eig. In the embodiment of the invention shown in FIG. 1, in principle, the same function is obtained when the output signal c from the integrator -IN- is supplied to the comparator -S2- instead of the limiting amplifier -BF2- and subtracted therefrom by I.