JPS582373B2 - Tire flat cover - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for detecting tire flats on wheels for railway vehicles.

When the braking force acting on the wheels of a railway vehicle becomes excessive compared to the adhesion limit force (product of adhesion coefficient and axle load) between the wheels and the rail, a so-called sliding phenomenon occurs in which the wheels continue to move while their rotation has stopped. This may cause the contact area of the wheel with the rail to be scraped flat.

This flattened portion is called a tire flat.

As is well known, wheels roll smoothly on rails in the absence of tire flats.

However, when a flat tire exists, the rail is impacted by the impact at that part, causing shocking vertical vibrations to the wheel axle, which not only induces vehicle body vibration via the axle spring and impairs riding comfort, but also causes damage to the rail. and impact loads may be applied to the wheels, causing damage.

In addition, the flat parts hit the rails with an impact, which caused a lot of noise.

For this reason, when inspecting or repairing a railway vehicle, tire flats on wheels are visually detected, and if the tire exceeds a set standard, the flat part is removed.

However, there is a problem in that it is difficult to visually detect a tire flat and requires a large number of personnel and time.

For this reason, there has recently been a demand for the development of a detection device that can quickly and accurately detect tire flats on wheels.

The present invention has been made to meet such demands, and its purpose is to provide a detection method that can easily detect wheel tire flats without making any changes to the existing rail tracks, sleepers, etc. It is on offer.

The present invention focuses on the fact that when the flatness of the wheel is large, the impact force applied to the rail increases proportionally, and as a result, the bending moment applied to the rail by the wheel increases. This system detects the bending moment and detects whether the tire is flat on the wheel.

Examples will be explained below.

FIG. 1 is a diagram showing an embodiment of the present invention, in which a rail 1 is supported by sleepers S1 to S3 provided on a trackbed 2. In FIG.

The detection devices G1 to G4 are provided at the lower end of the rail 1,
The bending moment caused by the wheels 8 is detected, and an example of this type of detection device is a resistance wire strain gauge.

The detection outputs of each of the detection devices G1 to G4 are added by an adder 3.

The output of this adder 3 is amplified by an amplifier 4, and unnecessary frequency components generated even by a normal wheel 8 are removed by a P wave amplifier 5.

Therefore, the output of the filter 5 is only the signal of the frequency component caused by the impact of the tire flat.

If the output of the p-wave device 5 is recorded using, for example, an XY recorder, it is possible to detect a flat tire of a wheel.

In the figure, the output of the tear wave device 5 is further input to a comparator 6, and the comparator 6 compares it with a predetermined reference value.

When the output of the filter 5 is larger than the reference value, the comparator 6 generates an output, and this output is sent to a display device or a recording device as described above to determine whether the tire of the wheel 8 is flat.

Although it is practically acceptable to arrange each of the detection devices G1 to G4 between the sleepers, on the sleepers, and on the lower surface of the rail between the sleepers, according to the inventor's experiments, the detection devices G1 to G4 can be arranged between the sleepers, on the sleepers, and on the lower surface of the rail between the sleepers. In the case of measuring the measurement section, it is better to arrange the detection devices G1 and G4 and the detection devices G2 and 03 symmetrically with respect to the sleeper S2, so that the output of the adder 3 when the wheels move through the measurement section is almost the same. It turned out to be the most suitable.

Although only the wheels 8 are shown in FIG. 1, the feature of this device is that it allows the vehicle to run on the existing rails on which this device is installed in the normal use condition without removing the wheel axle from the vehicle. Can detect tire flats on wheels.

Next, the operation of this device will be explained.

If the wheel 8 with a flat tire rolls in the direction of the arrow as shown in FIG. 2, the output of the adder 3 will be as shown in FIG. 2a.

This waveform shows the actual measurement value on a normal gravel roadbed, and the output generated when a normal wheel passes (excluding the high frequency component due to tire flat from Figure 2) is slightly different between A and B. Although there are some unevenness, it can be considered to be almost uniform.

This can be explained as follows.

That is, the wheel load (weight on wheels) is P1, the distance between sleeper S1 and point A is l1, and the distance between sleeper S1 and detection device G2 is 1!2.
shall be.

When the wheel is at point A in the center between the sleepers, the left and right sleepers mainly support the wheel load P, so the force applied to the sleepers is P/2, and the output of adder 3 is mostly the output of G1, The output is a value c・P/2l proportional to the moment P/2l1 at point A.
1 (where C is a proportionality coefficient).

When wheel 8 is on sleeper S2, sleeper S2' is used as the king.
supports the wheel load P, but since the trackbed is elastic, the sleeper s2
sinks, and a load is also applied to sleepers S1 and S3.

Assuming that value is a times P, the output of the adder 3 is as follows.

The components due to G1 and G4 are equally bending moment aPl1
The value CaPl1 is proportional to the bending moment aPl2, and the components due to G2 and G3 are also equal to the value CaPA proportional to the bending moment aPl2.
2, and the components due to G1, G2, G3, and G4 are their sum 2Ca(l1+l2)P, and as shown in the measured value shown in Figure 2a, when the wheel is at point A and when it is on sleeper S2, This is because the outputs of the adder 3 are almost equal.

That is, the neighbor when the wheel is on sleeper S2.

The force applied to the sleeper is aP1/4·l1/(l1+l2).

Since the value of a is a reasonable value, it is understandable that the output of the adder 3 is approximately equal when the wheel is at point A and when it is on sleeper S2.

If we think in the same way when there are wheels between point A and sleeper S2, we can understand that the output is almost the same as when the wheels are at point A.

The same applies to the point between sleepers S2B.

When the diamond flat hits the rail, the wheel load P fluctuates at the natural frequency of the vibration system consisting of the wheel rail, producing a high frequency component as shown in Figure 2, and the output of the wave generator 5 is as shown in Figure 2b.
Only the high frequency components are included, as shown in FIG.

It has been experimentally confirmed that the output sensitivity of this high frequency component is almost uniform between A and B, similar to the low frequency component, and if we consider that the above P varies, the same as the explanation for P above, can be explained.

The period between A and B will be referred to as a measurement section hereinafter.

In addition, in the above-mentioned example, the interval between measurement sections AB must be such that tire flatness can be detected over the entire circumference of the wheel.

Therefore, if it is not possible to measure the entire circumference of the wheel in the measurement section A-B as shown in Fig. 1, install a detection device between other sleepers (left side of S1 in the figure, between S2 and S4). , the outputs of all these detection devices may be summed by the adder 3.

However, if one measurement section is made too long, there is a problem that the sensitivity of the detection device decreases.

An embodiment of a tire flat detection device that solves this problem is shown in FIG.

In FIG. 3, G1' to G4' are newly added detection devices, and each detection device is arranged symmetrically to sleeper s3.

3' is an adder, 4' is an amplifier, and 5' is a wave generator, each having the same structure as 3, 4, and 5 shown in FIG.

9 and 9' are diodes for detecting the high value of the output of the door wavers 5 and 5'.

Measurement section consisting of G1, G2, G3, G4 and G1', G
The measurement section consisting of 2', G3', and G4' is G1' and G4.
There is no dead zone between the two measurement sections because there is overlap between them.

If the measurement section is divided into a plurality of sections in this way, the detection sensitivity of the detection device will not decrease.

Output sensitivity of amplifier 4 to wheel load P in measurement section consisting of G1, G2, G3, G4 and G1', G2', G3', G
If the output sensitivity of the amplifier 4' with respect to the wheel load P in the measurement section 4' is sufficiently matched, the configuration shown in FIG. 4 can be adopted.

That is, the high positions of the outputs of the amplifiers 4 and 4' are first extracted, and the high positions are fed into the wave wave device to extract the high frequency components caused by the tire flat.

This not only simplifies the device, but also has the advantage of being less susceptible to the effects of adjacent wheels.

In other words, if the test wheel is in the measurement section consisting of G1' to G4' and the adjacent wheel is to the left of sleeper S1, even if the adjacent wheel has a tire flat, the amplifier 4' Since the output is higher than the output of 4, the output of 4 is not taken out.

Therefore, points (G1' to G
Since the distance to the measurement section consisting of 4' is far,
The influence of adjacent wheels is reduced.

In a similar case, in FIG. 3, the measurement section G1 to G4 outputs an output due to the influence of the adjacent wheels, and since the output is close to the adjacent wheels, it is slightly larger than in the case of FIG. 4.

In the case of the method of extending the measurement section as shown in FIG. 3, there is a problem that when two wheels enter the measurement section, it is impossible to distinguish which wheel has a flat tire.

In order to accurately determine which wheel has a tire flat, the procedure shown in FIG. 5 can be performed.

In other words, if the length of one measurement section is approximately 1/2 the wheel circumference, and two measurement sections are provided at a distance equal to the wheel circumference, it is possible to detect tire flats around the entire wheel circumference, and it is possible to You can tell if there is a tire flat on the wheel.

In addition, when the measurement section shown in FIG. 5 is set to about 1/3 of the wheel circumference, three measurement sections may be provided at distances equal to the wheel circumference.

In short, when the measurement section is set to approximately 1/n of the wheel circumference, the measurement section may be provided at n locations at distances equal to the wheel circumference.

Practically speaking, it is preferable to set the measurement section to about 1/2 or 1/3 of the wheel circumference.

Although high frequency components caused by tire flats are extracted in Figures 1, 3, and 5, they are not necessarily limited to this, and the maximum value in temporal changes, etc. Tire flats can also be detected.

Furthermore, since the output value due to tire flatness depends on the vehicle speed and wheel load, the vehicle speed and wheel load may be detected by a device not shown, and the reference value may be corrected based on the detected values.

By the way, in addition to the present invention, at least two strain gauges are mounted on the rail at different distances from the sleepers, and the difference in shearing force generated on the rail when a wheel passes is detected, and the high frequency of the output is detected. Attempts have already been made to detect tire flats by detecting abnormal values of components.

However, when comparing the two, the present invention has the advantage that the change with respect to the rise time of the output that occurs when a normal wheel is rolling is slower, and as a result, the output change can be easily removed. be.

Therefore, the present invention can easily detect a tire flat even if the wheels roll at a higher speed than the above-mentioned attempts.

As explained above, the present invention detects the bending moment applied to the rail by the wheels and detects the tire flat of the wheels. Therefore, the present invention can be applied to existing ones without changing the rail track, sleepers, etc. Flat detection can be performed quickly and accurately, reducing vehicle inspection waiting time and improving vehicle operational efficiency.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a wheel tire flat detection device according to an embodiment of the present invention, FIG. 2 is a diagram for explaining its operation, and FIG. 3 is a diagram showing another embodiment of the present invention. FIG. 4 is a diagram showing a modification thereof, and FIG. 5 is a diagram showing still another embodiment of the present invention. Explanation of symbols, 1...Rule, 2...Dodoko, S...Sleeper,
G... Bending moment detection device, 3... Adder, 4...
Amplifier, 5... Filter, 6... Comparator, 7... Comparator output, 8... Wheel, P... Wheel weight, 9... Diode.

Claims (1)

[Scope of Claims] 1. When rolling a railway vehicle wheel on a rail and detecting tire flat of the wheel, detecting a bending moment applied to the rail by the wheel between sleepers supporting the rail. A plurality of means are provided on either the rail or the sleeper, and a measurement section between both ends of the plurality of adjacent detection means is set as a unit measurement section, and the tire flat of the wheel is determined by the sum of the outputs of the detection means within this measurement section. A method for detecting a tire flat on a wheel for a railway vehicle. 2. A railway vehicle wheel rolling on a rail to detect tire flat of the wheel,
A plurality of means for detecting the bending moment applied to the rail by the wheels between the sleepers supporting the rail are provided on either the rail or the sleeper, and a unit measurement section is defined between both ends of the plurality of close detection means. In addition, the length of the measurement section obtained by arranging a plurality of unit measurement sections in parallel is set to be approximately equal to the entire circumference of the wheel, and the sum of the outputs of the detection means within the measurement section is A method for detecting a tire flat of a wheel for a railway vehicle, characterized in that a tire flat of the wheel is detected. 3. In a railway vehicle wheel rolling on a rail to detect tire flat of the wheel,
The rail is provided with a plurality of means for detecting the bending moment applied to the rail by the wheels between the sleepers supporting the rail, and the plurality of detection means are arranged symmetrically with respect to the sleepers and are arranged close to each other. A tire flat for a wheel for a railway vehicle, characterized in that a measurement section between both ends of the detection means is taken as a unit, and a tire flat of the wheel is detected from the sum of the outputs of the detection means within the measurement section. Detection method. 4. A railway vehicle wheel that is rolled on a rail to detect tire flat of the wheel,
A plurality of means for detecting the bending moment applied to the rail by the wheels between the sleepers supporting the rail are provided on either the rail or the sleeper, and a unit measurement section is defined between both ends of the plurality of close detection means. At the same time, the length of the measurement section obtained by arranging a plurality of measurement sections of the unit in parallel is set to be approximately equal to 1/n wheel circumference of the wheel, and this measurement section is set to be equal to the entire circumference of the wheel. A method for detecting a tire flat on a wheel for a railway vehicle, characterized in that the tire flat of the wheel is detected from the sum of the outputs of the detecting means within the measuring section.