JPH0372943B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to the measurement and measurement of axial stress on installed rails, and in particular, the acquisition of data for measuring the axial stress of each installed rail and determining whether or not there is a problem with train operation. This is what we are trying to do.

<Background of the Invention> Generally, a track is provided with a clearance at the joint portion of the rail, and this clearance is used to absorb expansion and contraction deformation due to thermal expansion of the rail.

However, the joints of the rails have the disadvantage that they apply a large impact to the wheels and generate vibrations due to the impact, resulting in significant wear and fatigue of the rail pillows, track bed ballasts, etc., resulting in increased maintenance costs. It also makes the ride uncomfortable and is a weak point on the track from a safety standpoint. Against this background, long rails in which rails are continuously welded to eliminate seams are currently being put into practical use. A standard length rail of about 20 meters can expand and contract freely as the temperature changes, but if the rail is longer than this, the rail's expansion and contraction will be inhibited by the longitudinal track resistance between the track bed and sleepers, and the length of the rail will be approximately 200 meters, depending on the track structure. When the track length is longer than that, an immovable section occurs in the center of the rail, and the rail in this immovable section exhibits a phenomenon in which, in principle, it does not expand or contract at all throughout the year. Therefore, if the temperature conditions and track structure are the same, no matter how long the long rail becomes, the amount of expansion and contraction at the end of the rail can be made the same. In this way, the amount of expansion and contraction at the end of the long rail is quantified, and the amount of expansion and contraction is absorbed by the expansion joint.

However, in reality, in addition to temperature changes, braking or starting forces from trains are repeatedly applied to the rails. These external forces are not relatively gradual effects such as temperature changes, but sudden effects accompanied by vibrations or shocks. It expands and contracts due to external forces, creating internal stress.

On the other hand, in the stationary section, the thermal energy associated with temperature changes is not consumed by the expansion and contraction of the rail. In other words, all thermal energy is stored in the rail as thermal stress. At that time, the rail axial stress P (Kg) is determined by the elastic modulus of the rail steel being E (Kg/cm ² ) and the cross-sectional area of the rail being A.
(cm ² ), the coefficient of linear expansion is β (=1.14×10 ⁻⁵ ), and the temperature change since the rail was laid is Δt (° C.), the well-known following equation is obtained.

P=E・A・β・△t...(1) Therefore, buckling strength and welding strength that can withstand the axial stress P generated in the rail are required in the immovable section of the long rail.

In this way, axial stress is accumulated in the stationary section of the long rail due to thermal expansion and expansion/contraction deformation, so it would be convenient to be able to measure the axial stress of the rail and monitor whether it is within the safe limits.

<Prior art> As a conventional method for measuring axial stress, for example, a comparison rail is installed near the installed rail, with both ends free and capable of freely expanding and contracting, and the difference in the amount of expansion and contraction of both rails is used to determine the difference between the two rails. Methods of determining the axial stress of the rail, and methods of attaching a resistance wire strain gauge to the rail and measuring the amount of strain caused by expansion and contraction to determine the stress have been considered, but both methods require complicated installation and measurement methods, making it difficult to put them into practical use. It has some difficult drawbacks. For this reason, there have been no examples of this being carried out other than for some research purposes.

<Objective of the Invention> The present invention is intended to provide a method for measuring the axial stress of a laid rail that can be easily put into practical use.

<Summary of the Invention> In this invention, measurement marks are attached to two points separated in the longitudinal direction of the rail at approximately the same height from the bottom in the state before installation, and the distance between the marks is calculated. The rail temperature in that state and the rail number attached to the rail are stored, for example, in the memory of a computer, and the distance between the marks attached to the rail and the rail temperature are measured at an appropriate time after installation.
The axial stress of the installed rail can be calculated and determined by a computer based on the measured value and the measured value before installation.

In this case, the means for measuring the distance between measurement marks attached to the rail and the rail temperature may be of a portable type, for example.
The distance between the marks and the rail temperature of each rail are measured, and the measured data is encoded with the rail number and modulated with an audio frequency signal, and then transmitted to a computer via a telephone line etc. By storing the distance between marks and the rail temperature at that time in the free expansion/contraction state of the rail in advance in the computer's memory, and transmitting the data of the distance between the marks of the rail and the rail temperature measured after installation in the same way, the computer can The axial stress stored in each rail can be calculated from these data and the previously stored data in the free expansion and contraction state.

With this configuration, the status of a large number of rails can be managed, and in this respect, the practical effect is great.

<Embodiments of the invention> As the measurement mark to be attached to the rail, for example, a pin may be planted on the rail, or a marking line may be attached.
Possible options include pasting stickers. Here we will explain how to install pins on the rail.

The pin installation position is rail 1 shown in Figure 1.
Abdomen B is most suitable. In other words, when attaching marking lines, etc., it is possible to use the head A of the rail 1 as the mark attachment surface, but the drawbacks are that it wears out due to friction with the wheels that occurs when a train passes, and that it is easily contaminated by wind, rain, dust, etc. There is. In addition, when using either the marking line or the method of planting pins, it is possible to select the ventral side C as the mark mounting surface, but if the position of C overlaps with the mounting position of the rail coupling fitting 2. There are also scratches caused by crushed stone,
There may be damage etc.

Therefore, it is most suitable to set the mark mounting surface on the abdomen B of the rail 1.

An embodiment of the mark mounting structure is shown in FIGS. 2 and 3. The example shown in FIG. 2 shows a structure in which the cylindrical pin 3 is driven into the abdomen B of the rail 1. In other words, a hole is formed in multiple parts B of the rail 1, a small diameter part formed on the tip side of the pin 3 is press-fitted into this hole, and the pin 3 is implanted in the abdomen B of the rail 1 by this press-fitting. .

In the example shown in FIG. 3, a hole 4 having a relatively large diameter is formed in the abdomen B of the rail 1, and a pin 3 is housed in the hole 4. In other words, as shown in Fig. 4, the pin 3 has a flange 3a with a diameter slightly larger than the diameter of the hole 4, and a flange 3b that serves as a reference surface for measuring. 4 is selected to be approximately the distance between the flanges 3a and 3b.

With this structure, the pin 3 is connected to the hole 4.
It is possible to reduce the rate of exposure to wind and rain and to create a structure that is difficult to get dirty. Here, for example, a rubber cap 5 is fitted into the opening of the hole 4, and the structure is such that the rubber cap 5 can be removed as necessary, so that the circumferential surface of the pin 3, especially the circumferential surface of the flange 3b, gets dirty. It is possible to prevent measurement errors from occurring due to adhesion of dirt. In the structure shown in FIG. 2, the same effect can be obtained by covering the peripheral surface of the pin 3 with a rubber cap.

For example, the mark formed by pin 3 is 10 to 20.
They can be installed at intervals of about centimeters. In other words, the measurement accuracy can be increased by increasing the distance between marks. However, if the distance between the marks is made large, there arises a disadvantage that the measuring means for measuring the distance between the marks, which will be described later, becomes large. As a result, the distance between marks should be as small as possible from 10 to 20.
It is said to be about a centimeter. The coefficient of linear expansion of rail steel is 11.4 x 10 ^-6 , so if the distance between marks is set to 10 cm, the temperature will be 1°C.
The distance between marks expands and contracts by 1.14×10 ^-3 mm in response to a change in . If the measuring accuracy of the measuring method is 1/1000 mm, the temperature will be approximately ±1°C.
The accuracy is about the same as that of . If this level of measurement accuracy can be obtained, it is sufficient for practical use.

For example, 10 to 20 of the rail abdomen is shown in Figures 5 and 6.
An example of a measuring means for measuring the distance between measuring marks attached to two points separated by centimeters at substantially the same height from the bottom is shown. Figures 5 and 6
In the figure, 6 indicates a measuring means. The measuring means 6 can be composed of a reference plate 7 and a measuring device 8 mounted on the reference plate 7. The measuring device 8 includes a pair of contacts 8a and 8b and a displacement-electrical converter 8.
c. contact 8
Either one of a and 8b, for example 8a, is fixed to the reference plate 7, and the other contactor 8b is attached to the reference plate 7 so as to be movable in a direction parallel to the rail 1. For example, a knob 8E is provided on a movably mounted contact 8b on a displacement-electrical converter 8c, and the knob 8E is movable to engage with a gear on the shaft of the knob 8E and move back and forth in accordance with the rotation angle of the knob 8E. Rod 8
Connect d. The displacement-electrical converter 8c may be, for example, a differential transformer, a magnetic distance measuring device that measures the amount of movement by reading a magnetic pattern, or an optical distance measuring device that measures the amount of movement by reading Moire fringes. can be used.

The measuring means 6 is an attachment 9 whose position can be adjusted so that the contacts 8a and 8b have a predetermined positional relationship with respect to the pin 3 attached as a mark.
Supported by. Attachment 9 is base 9
a, a tightening knob 9b for tightening the base 9a to the bottom surface of the rail 1, a tightening tool 9c, and a movable base 9d supported so as to be movable in the vertical direction at one end of the base 9a. A height adjustment knob 9e for setting the height position of the movable base 9d and a height adjustment knob 9e that sets the movable base 9d so that the reference plate 7 is parallel to the abdomen B of the rail 1.
It can be configured by a fixed knob 9f that is fixed to the fixed knob 9f.

The base 9a is fixed to the bottom surface of the rail 1 using the tightening knob 9b, and the positional relationship in the height direction between the contacts 8a, 8b and the pin 3 is adjusted using the height adjusting knob 9e. At the position where the tip of the reference plate 7 contacts the abdomen B of the rail 1, the fixing knob 9f is tightened to fix the reference plate 7 to the movable table 9d.

By using the attachment 9 in this way, even if the standard of the rail 1 is different, the measuring means 6 can be attached in a predetermined relationship to the pin 3 marked as a mark.

In this installed state, by rotating the knob 8E, the movable contact 8b is moved from a reference position located at a distance of L ₁ from the contact point of the pin 3, which is set as one of the preset marks, toward the other mark pin 3.
By moving the contactor 8b by L ₂ and pressing it against the circumferential surface of the pin 3, the distance between the pins 3-3 is L ₁ +
L ₂ can be measured.

That is, in the displacement-electrical converter 8c, the movable rod 8d moves in the direction of the other pin 3 by rotation of the knob 8E. As the movable rod 8d moves, the contact 8b gradually moves toward the other pin 3, and when it comes into contact with that pin, the knob stops rotating. Displacement L ₂ of this movable rod 8d
For example, when a differential transformer is used as a distance measuring sensor, the output voltage changes because the magnetic coupling of the differential transformer changes in accordance with the displacement of the movable rod 8d. Therefore, by adding this output voltage to the reference voltage corresponding to the distance L ₁ of the reference position from one pin 3 given in advance, the voltage value corresponding to the distance between pins 3 and 3 can be obtained. Desired. This voltage value is converted into a digital signal by an analog-to-digital converter, and the digital signal is displayed on the display 15, thereby making it possible to know the value of the distance between the pins 3-3.

Temperature sensor 16 used as temperature measuring means
There are elements such as platinum resistance temperature detectors, thermistor resistance temperature detectors, and thermocouples, but those that measure with an accuracy of ±0.5°C are used. In FIG. 6, the temperature of the rail 1 can be measured by embedding a temperature sensor 16 in the tip of the reference plate 7 and bringing the temperature sensor 1 into contact with the abdomen B of the rail 1. That is, for example, when a thermistor temperature resistor is used as the temperature sensor 16, the resistance value of the thermistor temperature resistor changes due to a change in the temperature of the abdomen B of the rail 1. Therefore, if a voltage is applied to this thermistor temperature resistor, the temperature of the rail 1 is detected as a current value of the thermistor temperature resistor, and this output is given to the load resistor and can be detected as a voltage value. By converting this voltage value into a digital signal using an analog-to-digital converter and displaying the digital signal on the display 17, the temperature near the measuring mark pin 3 of the rail 1 can be known.

Here, in the present invention, this measured value is stored in the computer together with the number for the rail 1, so that the distance between marks can be registered for each rail. An example is shown in FIG. In the figure, numeral 11 indicates a portable measuring means carried on site. In this example, digital data measured by the measuring means 11 is transferred to a central monitoring station 13 via a telephone circuit 12, for example, and is transferred to a computer 14 provided at the central monitoring station 13.
This figure shows a case where the memory is configured to store digital data.

The measuring means 11 includes the above-described measuring means 6, a display 15 that displays the distance value between the mark pins 3-3 installed on the rail based on a digital electric signal output from the measuring means 6, and a temperature sensor 16. , a temperature display 17 that displays a digital electrical signal of the temperature measured by the temperature sensor 16, and these displays 15 and 1.
Transmitter/receiver 1 that transfers the digital value displayed at 7 to the central monitoring station 13 and also receives the calculation result sent from the central monitoring station 13 and displays it on the display 15.
8 and a keyboard 19 for inputting the number of the rail 1 or transmission and reception commands.

In addition to a computer 14, the central monitoring station 13 is provided with a transmitter/receiver 21, a display 22, and a printer 23 if necessary.

To transmit the data to the central monitoring station 13, input the number attached to the rail from the keyboard 19, and transmit the number and the measured value measured by the measuring means 6 and the temperature sensor 16 as digital signals to the central monitoring station 13.
to be transmitted.

The central monitoring station 13 receives the digital signal of the rail number and measured value sent from the measuring means 11, and inputs it into the computer 14. In this way, the distance between the marks is measured before the long rail is laid, that is, in the free expansion and contraction state, and the digital signal of the measured value is stored in the memory of the computer 14 as an initial value for each rail.

A long rail is laid, and the distance between the marks and the temperature of the rail 1 are measured again as digital signals at an appropriate time. The axial stress P currently stored in the rail 1 is determined from this measured value and the initial value. The calculation can be obtained as follows: P=E・S・△l/l...(2) △l=l ₁ -l ₂ ...(3). Here, l is the distance between the marks after installation, and E is the longitudinal elastic modulus of the rail (=2.1×10 ⁶
Kg/cm ² ), S is the cross-sectional area of the rail, △l is the amount of restrained expansion and contraction, and l ₁ is the amount of expansion with respect to the temperature difference in the free expansion and contraction state (this is calculated from the difference between the initial measured temperature and the current temperature). ), l ₂ is the amount of elongation due to temperature difference in the installed rail.

Equations (2) and (3) are calculated on the computer 14, and the value of the axial stress P of the rail 1 can be displayed on the display 22 and printed out on the printer 23 if necessary. Further, the calculation result can be transferred to the measuring means 11 and the value of the axial stress P can be displayed on the display 15.

<Effects of the Invention> As explained above, according to the present invention, marks are attached to the rail, the distance between the marks is measured when the rail is in a free expansion/contraction state, and the measured value converted to a digital signal is set as the initial value. is stored in the computer memory for each rail, and the axial stress P stored in the rail can be calculated by using the stored initial value and the digital measurement value after installation. Since each measurement data is input into the computer 14 according to the rail number, the status of a large number of rails can be managed, that is, whether the rails are within safety limits can be monitored. Furthermore, the measuring means 11 can be made compact by selecting a distance between marks of about 10 centimeters. As a result, it is easy to carry, so if a connection port for a telephone circuit is provided along the track, data can be sent to the central monitoring station 13 while moving sequentially.

In addition, in the above example, while measuring the measurement data, the central monitoring station 1
3, the measurement means 11 has a built-in microcomputer, the initial value of the free expansion/contraction state is registered in this microcomputer, and based on this initial value, the axis of the rail that occurs after installation is determined. It can also be configured to calculate stress.

In addition, instead of transmitting measurement data for each measurement, for example, one day's measurement data is stored in a memory device, and the data captured in the memory device is collectively transmitted to the central monitoring station 13. It is also possible to configure so that arithmetic processing is performed all at once. With this configuration, it is not necessary to provide a large number of telephone line connection ports along the track, and it is possible to obtain a more practical axial stress measurement of the installed rail.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view to explain the structure of the rail, Figures 2 and 3 are cross-sectional views to explain how the mark is attached, and Figure 4 is the structure of the pin used as the mark and the rubber cap for dust-proofing and waterproofing. 5 is a front view for explaining the structure of the measuring means, FIG. 6 is a side view thereof, and FIG. 7 is a diagram of the electrical system of the axial stress measuring device according to the present invention. FIG. 2 is a block diagram for explaining an example. 1: Rail, 3: Pin planted on the rail as a mark, 6: Measuring means, 14: Computer that memorizes the temperature of the rail and the distance between marks and calculates the axial stress.

Claims (1)

[Scope of Claims] 1. A. A rail number displayed on the rail; B. A measurement mark attached to the rail at two points separated in the longitudinal direction at approximately the same height from the bottom of the rail; C: A measuring means that measures the distance between the measuring marks and converts the measured distance into an electrical signal and outputs it; D: Measures the temperature of the rail near the measuring marks on the rail, and measures the measured temperature. E) a means for storing the distance obtained by the measuring means of the rail before installation and the temperature obtained by the temperature measuring means together with the rail number; F. the rail. After laying the rail, the distance between the measuring marks and the temperature of the rail are measured using the measuring means and the temperature measuring means, and the temperature of the rail is calculated using these measured values and the measured value before laying stored in the storing means. An axial stress measuring device for a laid rail, comprising: means for calculating axial stress; and display means for displaying the calculated value of the calculating means.