JPH0525055B2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Technical Field The present invention relates to a rail axial force device, and more specifically, the present invention relates to a rail axial force device that measures the rail axial force at main points of a laid rail and predicts buckling. The present invention relates to a rail axial force measuring device that can be useful for ensuring the safe operation of trains running on rails.

(b) Conventional technology Normally, in the track sections of fixed-length rails (25 m in length), gaps are provided at the rail joints to absorb the elongation of the rails during high temperatures in the summer. In addition, in the track section of the long rail (1.5 km long) made by welding fixed length rails on site, both ends of the rail are connected with expansion joints, so the approximately 200 m of both ends are expandable and contractible. Yes, but there are sleepers in the middle part,
Because the rails are restrained by track bed resistance such as ballast, compressive axial force is generated on the rails during high temperatures in the summer, and tensile axial force is generated in the winter. Also, this axial force is not uniform throughout the intermediate portion. The axial force of compression is particularly problematic. If the temperature of the rail increases too much, the axial force will overcome the lateral bed resistance and the rail will buckle. Furthermore, even in a state where buckling does not occur, if axial force is accumulated, the impact of the wheels when a train passes becomes a trigger, causing the rail to buckle. When the rail buckles, the buckled part bends suddenly, causing the train to derail and cause a major accident.

Therefore, if it is possible to measure the axial force generated on the rail before the rail buckles, appropriate countermeasures can be taken depending on the magnitude of the axial force, which will improve the safe operation of trains. can contribute.

There are mainly three types of conventional rail axial force measuring devices as follows.

(1) Measure the magnetic anisotropy of the rail and measure the axial force from the degree of anisotropy (see Japanese Patent Application Laid-Open No. 17330/1983).

(2) Simultaneously project ultrasonic transverse waves vibrating in directions parallel to and orthogonal to the direction in which the rail axial force is applied from the top of the rail head toward the bottom;
The axial force is measured by measuring the phase difference or time difference between the two reflected waves that have returned to the top of the head.
(See Publication No. 5625).

(3) Mark marks at regular intervals on the abdomen of the rail.
Alternatively, pins are installed at regular intervals, the rail temperature is measured, and the axial force is measured from the difference in the distance between the two points in the no-axial force state and in the axial force generation state (Japanese Patent Application Laid-Open No. 196449-1982) reference).

However, methods (1) and (2) described above have a problem in that the material of the rail, the residual stress, and the way of contact between the rail surface and the sensor affect the measured value. The above-mentioned method (3) has a problem that depending on the means for measuring the distance between marks, the accuracy may be low and the measured value may not be accurate. Furthermore, in all methods (1), (2), and (3), it is necessary to enter the track in order to measure the rail axial force, making the measurement work dangerous and causing safety problems. .

(c) Purpose The present invention was made in view of the above circumstances, and
The purpose is to create a rail system that is simple in configuration and easy to install, allows for stable, accurate, and automatic measurement of rail axial force at multiple locations over a long period of time, and does not involve any danger in the measurement process. An object of the present invention is to provide an axial force measuring device.

(d) Structure In order to achieve the above-mentioned object, the present invention provides a rail that is attached along the neutral axis of the rail and whose surface is subjected to moisture-proofing treatment so that the axial force acting in the long axis direction of the installed rail can be measured. In addition, there is an axial force detection section consisting of a Wheatstone bridge made up of multiple strain gauge elements fixed to the rail using a protective protector, and an axial force detection section that is installed at multiple locations on a wide range of laid rails. Storage means for respectively storing the arrangement position numbers of the plurality of axial force detection units, the unbalanced output i _p of the bridge circuit in the non-axial force state of the rail, and the axial force sensitivity coefficient K, and the axial force generation state of the rail. The unbalanced output of the above bridge circuit at
i _f , and the axial force F generated on the rail at that time
The present invention is characterized by comprising a calculation means for calculating the following using the calculation formula: F=( _ip -if)/ _K .

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

In the rail axial force measuring device of this embodiment, as shown in FIG. It is designed to be connected to a connector 52 of a digital processor 53 via a connector 51 forming a coupling portion 50 . This connector 52 is connected to the output of the axial force detection section 100 and the digital processor 53.
A power source 59 provided in the power source 59 is connected to the power source 59 . Unbalanced output signals inputted via the connectors 51 and 52 are inputted to the amplifying section 54. The output terminal of this amplifying section 54 is connected to the input terminal of a memory 56 which is a storage means via an A/D converter 55.
When receiving the unbalanced output of the axial force detection section 100, the output end subtracts the unbalanced output in the axial force generation state from the unbalanced output of the axial force detection section 100 in the no axial force state. It is connected to a calculation display 57 having calculation means for constant division. Note that reference numeral 58 is a controller for controlling the A/D converter 55 and the memory 56. The strain gauge pair 2 and 3 constituting the axial force detection section 100 are arranged along the neutral axes N and A on both sides of the abdomen of the rail to be measured 1 and the height direction axis, as shown in FIGS. 3 and 4. A holding plate 6 is attached to the underside of the rail 1 to be measured, and its surface is subjected to moisture-proofing treatment.
and is fixed to the rail 1 to be measured by fixing members 7 and 8.

With the bridge elements 10, 20, 30, and 40 made up of the strain gauge pairs 2 and 3 as four sides, the Wheatstone is placed so that it indicates a positive indication when a tensile force is applied in the longitudinal direction, and a negative indication when a compressive force is applied. Configure the bridge.

If the strain gauge pair 2 and 3 are bonded immediately after rail installation or setting change, the rail axial force is considered to be zero, so first, the axial force detection unit 1 at this point is
Measure the value of the unbalanced output of 00 to obtain i _p . This i _p
Let be the value of the non-axial force of the rail at the relevant measurement point.

Next, when the temperature of the rail 1 to be measured is raised and axial force is expected to be generated, when the value of the unbalanced output at the measurement point is measured again, the value of the unbalanced output at the measurement point _is measured. You will get a smaller value. Let this be _if . Here, the difference between i _p and i _f is a value proportional to the rail axial force.

In normal stress measurement, the material to be measured is strained by external force, so the amount of strain is measured to measure stress.However, the axial force of the rail caused by temperature rise is not due to external force, but internal strain. The thermal strain from This thermal strain can be measured by the same means as normal stress measurement, since the rail has been stretched due to the temperature rise, but is returned to the dimensions before the temperature rise by an external force. Furthermore, the change in the value of the unbalanced output with respect to a unit axial force, that is, the axial force sensitivity coefficient K, can be determined in the same manner as normal stress sensitivity. Therefore, the axial force is
It is obtained by dividing the difference between the unbalance value i _p when the axial force is zero at any point in time and the unbalance value i _f when the axial force is generated, by the axial force sensitivity coefficient K. That is, the axial force F can be determined as F=( _ip -if)/ _K .

In the embodiment shown in the first figure, the unbalanced output of the axial force detection section as an axial force detection sensor is passed through an amplifier with a constant sensitivity and then calculated by a digital processor to obtain the axial force F, which is displayed. ing.

In addition, detecting sections 100 configured as Wheatstone bridges by bonded strain gauge pairs 2 and 3 are installed at important points over a wide range of the installed rail 1 to be measured, and each of these sections has an extension. A connector 51 is connected via a cable or the like, and the connector 51 is extended and fixed to a steel pole or the like near the track bed where passing trains do not pose a danger to the measurement work.

In this embodiment configured in this manner, first, the axial force detection section 100 is installed on the rail 1 to be measured, and the connector 51 is coupled to the connector 52 of the digital processor 53. Then, the axial force detection section 10
The unbalanced output in the non-axial force state (initial state) of 0 is amplified by the amplifier 54 and then converted into a digital value by the A/D converter 55 and stored in the memory 56. At this time, the arrangement position number data of the axial force detection section 100 on the rail to be measured 1 inputted using a keyboard (not shown) provided in the controller 58 is also stored in the memory 56 along with the output of the A/D converter 55.
is stored in Furthermore, the above-mentioned axial force sensitivity coefficient K is similarly stored in the memory 56. By performing such an operation on the axial force detecting sections 100 provided at important points over a wide range of the rail 1 to be measured, so-called initial setting can be performed.

On the other hand, when measuring the rail axial force of the rail 1 to be measured at an arbitrary point in time, the axial force detection section 100 provided on the rail 1 to be measured and the connector 51 connected via an extension cable etc. are digitally processed. Vessel 5
3, and input the axial force detection unit arrangement number of the rail 1 to be measured using the keyboard of the controller 58. Then, the current unbalance value i _f is subtracted from the unbalance value i _p when there is no axial force, and the value divided by the axial force sensitivity coefficient K is displayed as a digital value on the calculation display section 57.

FIG. 2 is an example of test results on a 50N rail obtained by implementing the present invention. The horizontal axis is the rail to be measured 1
At a temperature of , the vertical axis shows the axial force, and the rail temperature is 20℃
It was obtained from the unbalance value i _p at the non-axial force of 20 °C and the unbalance value i _f at each subsequent temperature when increasing from 72 °C to 72 °C. Here, as the axial force sensitivity coefficient K, a value of 20×10 ⁻⁶ /tonf obtained through actual measurement was applied. The value of the rail axial force shown in Figure 2 is a commonly used calculation formula, and when the axial force F is calculated from F=E・β・S・△t, the temperature rises by 1°C for a 50N rail. Approximately 1.5 tonf per unit. Therefore, for a temperature increase of 50°C, the axial force is approximately 75 tonf, which is consistent with the results shown in FIG. In the above formula, E is Young's modulus (2.1×10 ⁶ Kg/cm ² ),
β is the coefficient of linear expansion of the rail (11×10 ⁶ ), S is the cross-sectional area of the rail (64 cm ² for a 50N rail), and Δt is the temperature rise of the rail.

If a self-temperature compensation type strain gauge element is used in the axial force detection section in the above embodiment, the temperature drift of the strain gauge element can be made extremely small, making it possible to measure rail axial force with extremely high accuracy. It is.

It should be noted that the present invention is not limited to the above-described embodiments, and can be modified in various ways without departing from the spirit thereof.

Moreover, the axial force detection section 100 in the above embodiment
constructed a Wheatstone bridge circuit using strain gauge elements on all four sides, but it is also possible to use strain gauge elements on two opposing sides and a fixed resistance on the other opposing side, or to use strain gauge elements on only one side. You can just use it.

In addition, in the embodiments shown in FIGS. 3 and 4, the bonding positions of the strain gauge pair 2 and 3 are aligned with the neutral axes N and A of the rail 1 to be measured. Axial force can be measured even if it is attached to the abdomen at a different position. When bonded at a position shifted from the neutral axes N and A, it can be used to detect when the roadbed near the detection section is subsided or raised. As in the above embodiment, when strain gauges are attached to positions corresponding to the neutral axes N and A on both sides of the abdomen of the rail 1 to be measured, even if there is a temperature difference between the front and back sides of the rail 1 to be measured, the effect will be can be electrically canceled out by configuring the corresponding strain gauge element with a bridge circuit configuration, so that it is possible to extract an output based only on the axial force.

Furthermore, when the rail to be measured buckles, the rail to be measured is bent to an extreme degree, so that the unbalance value of the detecting section becomes large, and an abnormal state can be detected even at a location distant from the detecting section. If a Wheatstone bridge is configured with a strain gauge glued to one side of the rail abdomen and used as a detection unit, the accuracy of axial force measurement will decrease slightly, but the sensitivity to horizontal bending deformation of the rail will increase.

Furthermore, the strain gauge element may be attached by welding or other means in addition to adhesion.

(d) Effect As described above, according to the rail axial force measuring device according to the present invention, the axial force of the rail can be measured at a position outside the track bed. , it has the advantage of being able to measure accurately without being affected by rail material, rail current, or residual stress.

In addition, once the rail axial force is measured immediately after the rail is laid or when the rail setting is changed, when the rail axial force is considered to be zero, the person in charge can go around at any time and measure the axial force regardless of train operation. By accumulating the measured data, it becomes possible to manage the axial force in consideration of weather conditions, which has a great effect on safe train operation.

Furthermore, if the measurement points are spread over a wide area, it is impossible to follow weather changes because patrolling by the person in charge requires manpower and time. In such a case, the digital processor 53 of the present invention can By adding a face circuit and using a telephone with a modem function and a telephone line, it is possible to measure the axial force of the rail at a wide range of measurement points in a short time, and centrally manage it from one central location.

Furthermore, it is also easy to place a transmitter connected to an axial force detection section near the railroad track, and mount a receiver on a vehicle to measure while the vehicle is running.

Furthermore, the method of the present invention using a strain gauge element as a rail axial force detection sensor allows simple conversion from axial force to electricity when managing axial force, and is suitable as a sensor for an axial force measuring device.

Furthermore, since the axial force detecting section according to the present invention is attached along the neutral axis of the rail so as to be able to measure the axial force acting in the longitudinal direction of the rail, the trackbed near the axial force detecting section is If the axial force sensor sinks or rises, or if the axial force detector sinks or rises while a train is passing, the sinkage or rise may cause the rail to curve upward or downward. is not affected by it,
It is possible to output an output that truly corresponds only to the axial force.

In other words, even when a train is passing on the rail at the location where the axial force detection unit is installed, the weight of the train is not felt and only the axial force of the rail can be accurately detected, so that the impact caused by the passing of the train is reduced. Rail buckling, which may occur as a trigger, can be predicted early on, making it possible to prevent train derailments.

In addition, the axial force detection unit made of the strain gauge element according to the present invention is attached to the rail, and its surface is subjected to moisture-proofing treatment, and is fixed to the rail using a protective protector, so it is protected against rainwater. Even if it is exposed to dust or is subjected to impact from stones or other foreign objects, there is very little risk of oxidation, insulation deterioration, or damage, and it is possible to perform stable measurements over a long period of time. can.

As explained above, the rail axial force measuring device of the present invention has, firstly, a simple configuration and easy installation on the rail, and secondly, the rail axial force measuring device of the present invention measures the axial force of the rail at a safe position outside the track bed. Third, compared to methods using ultrasonic waves or electricity, rail axial force can be measured with high precision without being affected by rail material, rail current, or residual stress. Fourth, , even when the train is passing over the rail at the location where the axial force detection unit is installed, the weight of the train is not felt and only the axial force of the rail can be accurately detected. It is possible to quickly predict rail buckling, which can be triggered by impact, and prevent train derailment.Fifth, even if exposed to rainwater or dust, it can be Sixthly, there is very little risk of deterioration of the axial force detection function due to oxidation, deterioration of insulation, damage, etc. even if it is subjected to impact from some foreign object, and stable measurement can be performed over a long period of time.Sixthly,
By adding an interface circuit to this device and using a telephone with a modem function and a telephone line, it is possible to measure the axial force of the rail at a wide range of measurement points in a short time. It has many great advantages, such as being able to manage...

[Brief explanation of the drawing]

FIG. 1 is a circuit block diagram showing the configuration of the present invention, FIG. 2 is a diagram showing an example of measurement results, and FIG. 3 is a perspective view showing the bonded state of a pair of strain gauges for measuring rail axial force. FIG. 4 is a sectional view showing how the axial force detection sensor is attached to the rail. 1... Rail to be measured, 2, 3... Strain gauge pair, 4, 5... Protector, 6... Holding plate, 7,
8... Fixed member, 10, 20, 30, 40... Bridge element, 51, 52... Connector, 53...
Digital processor, 54...Amplifier, 55...
A/D converter, 56...Memory, 57...Calculation display, 58...Controller, 59...Power supply, 100
...Axial force detection section.

Claims (1)

[Scope of Claims] 1. A protector is attached along the neutral axis of the rail to measure the axial force acting in the long axis direction of the installed rail, and the surface thereof is subjected to moisture-proofing treatment. an axial force detecting section configured with a Wheatstone bridge made up of a plurality of strain gauge elements fixed to the rail using a Storage means for storing the position number, the unbalanced output i _p of the bridge circuit in the non-axial force state of the rail, and the axial force sensitivity coefficient K, respectively, and the unbalanced output i of the bridge circuit in the axial force generation state of the rail. A rail axial force measuring device characterized by comprising: calculation means for receiving _f and calculating the axial force F generated on the rail at that time using the calculation formula F = (i _p - i _f )/K. .