JP2009264792A - Measuring method of horizontal pressure - Google Patents

Abstract

An object of the present invention is to erroneously judge the risk of derailment even if the lateral pressure is determined based on the sum of both the lateral displacement of the wheel caused by the lateral pressure and the displacement due to the processing accuracy of the wheel measurement surface. To prevent that.
A lateral pressure generated at a wheel of a running railway vehicle is measured. The displacement amount of the wheel measured during traveling is stored for a predetermined time. Of the stored displacement amounts, the lateral pressure is obtained from the average value of the latest data per one wheel rotation.
[Effect] Since the fluctuation caused by the displacement due to the processing accuracy of the wheel measurement surface is suppressed, even when the displacement due to the processing accuracy of the wheel measurement surface overlaps when the lateral displacement of the wheel due to lateral pressure is maximum Exceeding the threshold value can be effectively prevented, and errors in determining the risk of derailment are reduced.
[Selection] Figure 1

Description

  The present invention relates to a method for measuring a lateral pressure acting between a wheel and a rail of a railway vehicle.

  When manufacturing new vehicles or constructing new railroads, it is necessary to check their safety. Also, the state of the force acting between the wheel and the rail changes over time from the time of manufacturing a new vehicle or the opening of a new line due to changes in the coefficient of friction and the state of the track. For this reason, it is necessary to confirm the safety of the business line.

  Railroad vehicle travel safety is defined by the horizontal force (lateral pressure) acting between the wheels and the rails as Q, and the vertical force acting between the wheels and the rails (wheel load) as P. In this case, it is expressed by Q / P (derailment coefficient). Therefore, the derailment coefficient can be obtained by measuring the lateral pressure Q and the wheel load P.

Therefore, in order to evaluate the above-mentioned safety, wheel load and lateral pressure are measured from the vehicle, but a special wheel shaft (PQ wheel shaft) is necessary for measuring these wheel load and lateral pressure. It cannot be measured easily.
Supervised by the Railway Bureau of the Ministry of Transport, edited by the Railway Technical Research Institute “Conventional Railway Driving Speed Improvement Test Manual / Commentary” The Railway Technical Research Institute, May 10, 1993, p67-76 “Tsushin” Sumitomo Metal Technology Co., Ltd., April 1, 2002, Spring 2002 No. 35

  That is, the measurement using a PQ wheel shaft measures the wheel load and lateral pressure which act on a wheel by sticking a strain gauge to a wheel and measuring the deformation distortion of the wheel. For this reason, a C-type integrated rolling wheel having a straight plate portion is manufactured, a strain gauge is attached in a hole opened in the plate portion of the wheel, and the hole is elliptically deformed by contacting the wheel with the rail. The vertical force acting on the wheel is measured by capturing the amount of deformation at the time. Further, the lateral pressure acting on the wheel is measured by capturing the deformation amount of the plate portion of the wheel that is bent and deformed by the lateral pressure by a strain gauge attached to the plate portion of the wheel.

  However, in the method using the PQ wheel shaft, since it is necessary to extract a signal from the rotating wheel shaft to the non-rotating system, a hole is made in the axle and the measurement wiring is penetrated. Fatigue strength cannot be secured except for boring axles for which strength calculation is also performed.

  In addition, a slip ring is used to extract a signal from the rotating wheel shaft to the non-rotating system. However, when the slip ring is worn, measurement is impossible. It is also necessary to calibrate the strain gauge periodically. In addition, the braking force cannot be applied to the PQ axis, which affects the deceleration.

  In addition to this, there is an FM telemeter system, but in this method, it is necessary to attach a telemeter transmitter for wirelessly transmitting a signal from the sensor to the axle, and a power supply source for transmission is required.

  For the above reasons, with the method using the PQ wheel axle, it has not been possible to diagnose safety related to changes in track conditions from the vehicle over a long period of time on the business line. For this reason, it is desired to easily measure these forces on the business line, in particular to observe the state of the track, and diagnose its safety from the vehicle.

Therefore, the applicant arranges a non-contact displacement meter on a member that rotatably supports the wheel shaft, and the displacement amount of the wheel rim portion or plate portion measured during traveling and the wheel rim portion or plate determined in advance. A method for obtaining the lateral pressure from the converted value of the displacement amount of the portion and the lateral pressure has been proposed (Patent Document 1).
JP 2006-88967 A

According to the method proposed by the applicant, it is possible to measure the lateral pressure acting on the wheel during traveling over a long period of time on the business line.

  However, the value measured by the displacement meter includes both the lateral displacement of the wheel caused by the lateral pressure and the displacement due to the processing accuracy of the wheel measurement surface.

  The wheel has high rigidity, and the lateral displacement of the wheel caused by the lateral pressure is very small. On the other hand, the amount of displacement due to the processing accuracy of the wheel measurement surface is approximately the same as the amount of lateral displacement of the wheel within one rotation, and this value is added to the displacement due to the lateral pressure every rotation of the wheel.

  Since the left and right displacements of the wheel caused by these lateral pressures and the number of digits of displacement due to the processing accuracy of the wheel measurement surface are similar to the above, just looking at the measured values, It is difficult to know only the displacement amount.

  Accordingly, when the displacement amount due to the processing accuracy of the wheel measurement surface is overlapped when the lateral displacement amount of the wheel due to the lateral pressure is the maximum, the determination threshold may be exceeded due to the overlap. In such a case, even if there is actually no risk of derailment, it may be erroneously determined that there is a risk of derailment.

  Incidentally, FIG. 3 (a) shows the lateral pressure at the time of curve traveling in the low speed traveling section obtained by the method of Patent Document 1, and FIG. 3 (b) shows the lateral pressure at the time of curved traveling in the high speed traveling section. It can be seen that the fluctuation width undulated for each rotation of the is a large value.

  The problem to be solved by the present invention is a value obtained by adding both the lateral displacement of the wheel caused by the lateral pressure and the displacement due to the processing accuracy of the wheel measurement surface to the lateral pressure obtained by the method of Patent Document 1. In other words, the risk of derailment may be misjudged.

The method for measuring lateral pressure according to the present invention includes:
Danger of derailment by obtaining a more accurate value even if the lateral pressure is determined based on the sum of both the lateral displacement of the wheel caused by the lateral pressure and the displacement due to the processing accuracy of the wheel measurement surface. To prevent misjudgment of sex,
A method for measuring the lateral pressure generated on the wheels of a running railway vehicle,
It is most important to store the displacement amount of the wheel measured during traveling for a certain period of time and to obtain the lateral pressure from the average value of the latest data per one rotation of the wheel among the stored displacement amount. Features.

  In the present invention, the lateral pressure is not obtained by using the displacement amount of the wheel measured during traveling as it is, but the lateral pressure is obtained from the average value of the latest data per one rotation of the wheel. There is an advantage that fluctuation due to the displacement is suppressed.

  Therefore, when the lateral displacement of the wheel due to the lateral pressure is maximum, even if the displacement due to the processing accuracy of the wheel measurement surface overlaps, it can be effectively prevented that the judgment threshold is exceeded, and the risk of derailment can be judged. The error is reduced.

  The best mode for carrying out the present invention will be described below with reference to FIGS. 1 and 2 together with the process from the idea of the present invention to the solution of the problem.

  The value measured by the displacement meter includes not only the lateral displacement of the wheel caused by lateral pressure, but also the displacement due to the processing accuracy of the wheel measurement surface. To improve the processing accuracy of this wheel measurement surface, There is a limit and it is impossible to make it zero. Further, in order to improve the processing accuracy, the cost required for processing becomes high.

  Therefore, the inventors examined smoothing a value with a large vibration width that was measured for each rotation of the wheel, measured by a displacement meter.

  As a method of smoothing the vibration waveform, there is a moving average process in which measured values are stored, a certain number of data is extracted from the latest data, averaged, and the result is obtained.

  Since this moving average processing is calculated with data of a constant sampling number with a constant sampling period, for example, if the sampling period is 5 milliseconds, the sampling number is 500, and the wheel diameter is 860 mm, the high speed is 50 km / h. When running, the average of 5.1 rotations of the wheel, and when driving at a low speed of 5 km / h, the average of about half a wheel rotation.

  3 (a) and 3 (b) are obtained by performing a moving average process on the lateral pressure with a sampling number of 200 milliseconds in the low-speed traveling section and with a sampling number of 2 seconds in the high-speed traveling section. ) (B).

  In a low-speed traveling section in which moving average processing is performed with a sampling number suitable for high-speed traveling, a small amount of data is averaged. Therefore, although the diagram in FIG. It is almost the same as the diagram (a), and the meaning of averaging is lost.

  On the other hand, since a lot of data is averaged in the high-speed traveling section in which the moving average processing is performed with the sampling number suitable for low-speed traveling, the steady-state value can be seen in the diagram of FIG. Minor changes (for example, between 10 and 11 seconds on the horizontal axis) have disappeared. In addition, the timing of fluctuation at the entrance / exit of the curve is also delayed.

  In this way, in the case of moving average processing that calculates with a fixed sampling number of data with a fixed sampling period, either smoothing during low-speed driving or high-speed driving cannot be performed, and it responds to changes in the speed of railway vehicles. Can not do it.

  Although various filter processes are performed, there is a method of changing the filter process cutoff frequency in a timely manner according to the speed. However, the value may change abruptly when the frequency is changed. In addition, the number of filter setting constants becomes enormous, which reduces the memory capacity and increases the load required for calculation.

  Therefore, the inventors considered changing the number of data to be extracted depending on the traveling speed. That is, in the conventional moving average processing, what was handled and averaged as time-based data was considered to be handled and averaged as distance-based data.

  At this time, if the number of data is too large, the moving average process is performed on a high-speed traveling section with a cycle suitable for low-speed traveling, and the fluctuation is hidden due to excessive smoothing, and the load required for the calculation also increases. .

  On the other hand, the displacement due to the processing accuracy of the wheel measurement surface is the same for each rotation of the wheel, and the number of data for one wheel rotation of the railway vehicle is 70 ms per hour when the sampling cycle is 5 milliseconds and the wheel diameter is 860 mm. The number of data is about 28 and about 980 at 2 km / h, so the number of data is neither too much nor too little.

  For this reason, the inventors store the measured displacement value in the memory for a certain period of time from the latest data, take out the latest data per rotation of the wheel from this, and average these values as the result. The method of the present invention was established.

That is, the method for measuring lateral pressure according to the present invention includes:
A method for measuring the lateral pressure generated on the wheels of a running railway vehicle,
The displacement amount of the wheel measured during traveling is stored for a predetermined time, and the lateral pressure is obtained from the average value of the latest data per one rotation of the wheel among the stored displacement amount.

  Results obtained by averaging the lateral pressure shown in FIGS. 3 (a) and 3 (b) by the method of the present invention are shown in FIGS. 1 (a) and 1 (b).

  When the lateral pressure is obtained from the average value of the latest data per one rotation of the wheel by the method of the present invention, in the low-speed traveling section, as shown in FIG. It can be seen that even at low speeds, fluctuations in values that seem to be displacement due to wheel machining accuracy disappear.

  Further, in the method of the present invention, the fluctuation of the lateral pressure value can be seen even in the high-speed traveling section shown in FIG. It can be seen that the fluctuation of the lateral pressure value is reduced in a large fluctuation portion (for example, after 16 seconds on the horizontal axis).

  By the way, according to the lateral pressure measuring method of the present invention, the number of necessary data approaches extremely infinite when traveling at extremely low speed. Therefore, the calculation may not be performed when the number of stored data is limited or when the traveling speed becomes a constant speed, for example, 2 km / h or less.

  By doing so, it is possible to calculate the displacement of the wheel measurement surface while suppressing the memory capacity and load required for the calculation without requiring high-precision machining accuracy.

  The embodiments of the present invention have been described above, but the present invention is not limited to these exemplifications, and it goes without saying that the embodiments can be appropriately changed within the scope of the technical idea shown in the claims.

  For example, the measurement value employed in the method of the present invention is not limited to that measured by the method disclosed in Patent Document 1, and may be a value measured by any method.

  The present invention described above can be applied not only to the measurement of the lateral pressure acting on the wheels of the railway vehicle but also to the measurement of the lateral pressure of other vehicles.

(A) is the figure which showed the lateral pressure at the time of curve driving | running | working in the low-speed driving | running | working area calculated | required by the method of this invention, (b) is the figure which showed the lateral pressure at the time of curve driving | running in the high-speed driving | running area. (A) (b) is the figure which showed the result of having performed the moving average process to the figure of Fig.3 (a) (b). (A) (b) is the figure which showed the original data of FIG. 1, FIG. 2 calculated | required by the method of patent document 1. FIG.

Claims (1)

A method for measuring the lateral pressure generated on the wheels of a running railway vehicle,
The displacement amount of the wheel measured during traveling is stored for a predetermined time, and the lateral pressure is obtained from the average value of the latest data per one rotation of the wheel among the stored displacement amount. Measuring method of lateral pressure.

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