JP7560740B2 - Wheelbase measurement system and method - Google Patents

Description

This disclosure relates to a measurement system and method for measuring the wheelbase of bogies for railway vehicles.

A bogie for a rail vehicle typically comprises front and rear wheel sets and a bogie frame. Each wheel set includes an axle and left and right wheels.

For example, when maintaining bogies for railway vehicles, the distance between the front and rear wheelsets (wheelbase) is measured. The wheelbase must be measured accurately and adjusted appropriately. If the wheelbases on the left and right sides of the bogie are different, the bogie may turn even when the railway vehicle is traveling in a straight line.

Patent Document 1 discloses a measuring device for measuring the wheelbase of a bogie for a railway vehicle. The measuring device of Patent Document 1 includes a long, elongated main body configured to be slidable in the longitudinal direction, first and second measuring units provided at both ends of the main body, and a lifting mechanism that holds the second measuring unit so that it can be raised and lowered. When measuring the wheelbase with the measuring device, the first and second measuring units are placed on the wheels of the front and rear axles while the main body is slid and the lifting mechanism is used to raise and lower the second measuring unit. In this state, the diameter of each wheel is measured by measuring devices provided on the first and second measuring units, respectively. In addition, detectors provided on the main body and the second measuring unit detect the amount of sliding of the main body and the amount of lifting of the second measuring unit. The wheelbase is calculated based on the diameter of each wheel, the amount of sliding of the main body, and the amount of lifting of the second measuring unit.

Japanese Patent Application Publication No. 8-184401

In the measuring device of Patent Document 1, when measuring the wheelbase, the first and second measuring units are placed on the wheels of the front and rear axles. Therefore, when measuring the wheelbase, the body of the railway vehicle must be removed from the bogie. The measuring device of Patent Document 1 cannot measure the wheelbase while the body of the railway vehicle is still attached to the bogie (in its current state).

The objective of this disclosure is to provide a measurement system that can measure the wheelbase of a railway vehicle bogie even when the bogie is in its current position.

The measurement system according to the present disclosure is a measurement system for measuring the wheelbase of a bogie for a railway vehicle. The measurement system includes a rail, a first strain gauge, a second strain gauge, and a processing device. The rail includes a top surface. The front and rear wheels of the bogie contact the top surface. The first strain gauge is positioned offset in the width direction of the rail from the contact position of the wheels on the top surface. The first strain gauge is affixed to the top surface. The second strain gauge is positioned offset in the width direction of the rail from the contact position of the wheels on the top surface, and is spaced apart from the first strain gauge in the longitudinal direction of the rail by the design value of the wheelbase of the bogie. The second strain gauge is affixed to the top surface. The processing device acquires output data output by the first strain gauge and the second strain gauge in response to the load applied from the bogie to the top surface. The processing device determines the deviation of the wheelbase of the bogie from the design value based on the output data of the first strain gauge and the second strain gauge at the same time, or based on the time when the peaks of the output data of the first strain gauge and the second strain gauge occur.

The measurement system disclosed herein makes it possible to measure the wheelbase of a railway vehicle bogie even when it is in its current position.

FIG. 1 is a side view of a bogie for a railway vehicle. FIG. 2 is a plan view of the wheelbase measurement system according to the first and second embodiments. FIG. 3 is a flowchart showing the wheelbase measuring method according to the first and second embodiments. FIG. 4 is a schematic diagram for explaining the wheelbase measuring method according to the first and second embodiments. FIG. 5 is another schematic diagram for explaining the wheelbase measuring method according to the first and second embodiments. FIG. 6 is a diagram illustrating the calibration data used in the first embodiment. FIG. 7 is a schematic diagram for explaining an example of a method for acquiring the calibration data shown in FIG. FIG. 8 is a cross-sectional view of a rail in the third embodiment. FIG. 9 is a cross-sectional view of a rail in the fourth embodiment. FIG. 10 is a plan view of a wheelbase measurement system according to the fourth embodiment. FIG. 11 is a plan view of a wheelbase measurement system according to a modified example of each of the above embodiments.

The measurement system according to the embodiment is a measurement system for measuring the wheelbase of a bogie for a railway vehicle. The measurement system includes a rail, a first strain gauge, a second strain gauge, and a processing device. The rail includes a top surface. The front and rear wheels of the bogie contact the top surface. The first strain gauge is positioned offset in the width direction of the rail from the contact position of the wheels on the top surface. The first strain gauge is affixed to the top surface. The second strain gauge is positioned offset in the width direction of the rail from the contact position of the wheels on the top surface, and is spaced apart from the first strain gauge in the longitudinal direction of the rail by the design value of the wheelbase of the bogie. The second strain gauge is affixed to the top surface. The processing device acquires output data output by the first strain gauge and the second strain gauge in response to the load applied from the bogie to the top surface. The processing device determines the deviation of the wheelbase of the bogie from the design value based on the output data of the first strain gauge and the second strain gauge at the same time, or based on the time when the peaks of the output data of the first strain gauge and the second strain gauge occur (first configuration).

According to the measurement system of the first configuration, the first strain gauge and the second strain gauge attached to the top surface of the rail can obtain output data indicating the strain generated in the rail in response to the load applied from the bogie to the top surface. In addition, the processing device automatically determines the deviation of the wheelbase of the bogie from the design value based on the output data of the first strain gauge and the second strain gauge at the same time, or the time when the peaks of the output data of the first strain gauge and the second strain gauge occur. Therefore, the actual wheelbase can be measured. Such wheelbase measurement can be performed simply by moving the bogie on the top surface of the rail. Therefore, the wheelbase can be measured regardless of whether the car body of the rail vehicle is attached to the bogie or not, and there is no particular need to remove the car body from the bogie when measuring the wheelbase. Therefore, according to the measurement system of the first configuration, the wheelbase of a rail vehicle bogie can be easily and quickly measured even when it is in its current state.

In the first configuration, the first strain gauge and the second strain gauge are each positioned offset in the width direction of the rail from the wheel contact position on the top surface. This makes it possible to avoid interference between each strain gauge and the wheel.

In the above measurement system, the processing device may determine the deviation of the wheelbase of the bogie from the design value based on the output data of the first strain gauge and the second strain gauge at the same time and the calibration data acquired in advance. The calibration data may include information indicating the relationship between the longitudinal distance from each of the first strain gauge and the second strain gauge to the contact position of the wheel with the top surface and the output data of each of the first strain gauge and the second strain gauge (second configuration).

In the second configuration, when determining the deviation of the wheelbase of the bogie from the design value, in addition to the output data of the first strain gauge and the second strain gauge at the same time, previously acquired calibration data is used. In this case, even if the first strain gauge and/or the second strain gauge is not attached precisely to the specified position, there is almost no effect on the measurement of the wheelbase, so the wheelbase can be measured more accurately. In addition, if the measurement of the wheelbase is affected by changes over time in the measurement system, such as deterioration of each strain gauge, the effects of changes over time can be eliminated by periodically reacquiring and updating the calibration data. This makes it possible to measure the wheelbase accurately over the long term.

In the above measurement system, the top surface of the rail may include at least one recess. The at least one recess may be positioned, for example, offset in the width direction of the rail from the wheel contact position on the top surface. At least one of a first strain gauge and a second strain gauge may be positioned within the recess (third configuration).

In the third configuration, at least one of the first and second strain gauges is disposed in a recess provided in the top surface of the rail. This makes it possible to more reliably avoid interference between each strain gauge and the wheels.

In the above measurement system, at least one of the portions of the top surface of the rail where the first strain gauge is attached and the portions where the second strain gauge is attached may have a convex shape when viewed in cross section of the rail (fourth configuration).

The contact position of the wheel on the top surface may vary in the width direction of the rail due to wear of the wheel, etc. However, in the fourth configuration, at least one of the parts of the top surface of the rail where the first strain gauge is attached and the parts where the second strain gauge is attached has a convex shape when viewed in the cross section of the rail, and the wheel can be stably contacted at the highest point of the top surface near the first strain gauge and/or the second strain gauge. That is, the contact position of the wheel can be controlled so that the contact position of the wheel does not vary in the width direction of the rail, at least in the vicinity of the strain gauge. Therefore, it is possible to avoid the wheel interfering with the strain gauge due to the variation in the contact position of the wheel. In addition, it is possible to suppress the occurrence of errors in the output data of the strain gauge and the measurement of the wheelbase using this due to the variation in the contact position of the wheel in the width direction of the rail. Furthermore, since the contact position of the wheel on the top surface of the rail is stable, the strain gauge can be brought closer to the contact position, and the detection sensitivity and detection accuracy of the strain gauge when measuring the wheelbase can be improved.

In the above measurement system, a rail, a first strain gauge, and a second strain gauge may be provided corresponding to the front and rear wheels arranged on the left side of the bogie, and a rail, a first strain gauge, and a second strain gauge may be provided corresponding to the front and rear wheels arranged on the right side of the bogie (fifth configuration).

A measurement method according to an embodiment is a method for measuring a wheelbase of a bogie for a railway vehicle, the measurement method including the following steps (sixth configuration).
a) preparing a rail including a top surface, a first strain gauge attached to the top surface, and a second strain gauge attached to the top surface at a distance from the first strain gauge in the longitudinal direction of the rail by a design value of the wheelbase of a bogie;
b) moving the bogie on the top surface so as not to interfere with the first strain gauge and the second strain gauge, and acquiring output data outputted by the first strain gauge and the second strain gauge; and c) determining the deviation of the wheelbase of the bogie from the design value based on the output data of the first strain gauge and the second strain gauge at the same time, or based on the occurrence times of peaks in the output data of the first strain gauge and the second strain gauge.

The measurement system and the measurement method according to the embodiment of the present disclosure will be described below with reference to the drawings. In each drawing, the same or equivalent components are given the same reference numerals, and the same description will not be repeated.

First Embodiment
[Trolley]
First, the configuration of a bogie whose front-rear axle distance (wheelbase) is measured by the measurement system and measurement method according to each embodiment will be described. Fig. 1 is a side view of a bogie 10 for a railway vehicle, and shows a simplified schematic of the configuration of the bogie 10. In this embodiment, for convenience of explanation, the left-right direction on the plane of Fig. 1 is defined as the front-rear direction of the bogie 10, and the up-down direction on the plane of Fig. 1 is defined as the up-down direction of the bogie 10. The front-rear direction is the direction in which the bogie 10 runs or moves. In addition, the depth direction in Fig. 1 is defined as the left-right direction of the bogie 10.

As shown in FIG. 1, the bogie 10 includes wheel sets 11F, 11R and a bogie frame 12. The wheel set 11F is disposed at the front of the bogie 10. The wheel set 11R is disposed at the rear of the bogie 10. Each of the wheel sets 11F, 11R includes an axle 111 and wheels 112. The axle 111 extends in the left-right direction of the bogie 10. Wheels 112 are attached to the left and right ends of the axle 111, respectively. The bogie frame 12 supports the wheel sets 11F, 11R.

In this embodiment, the bogie 10 is typically a steering bogie. A steering bogie is a bogie that steers the wheelsets 11F, 11R so that the wheelbase between the wheelsets 11F, 11R is longer on the outer rail side and shorter on the inner rail side when the railway vehicle passes through a curve, and runs with the direction of the wheelsets 11F, 11R aligned with the direction of the curve. However, the bogie 10 may also be a normal bogie in which the wheelsets 11F, 11R remain parallel and the wheelbase between the wheelsets 11F, 11R does not change.

[Measurement system]
Next, a schematic configuration of a measurement system 20 for measuring the wheelbase of the bogie 10 will be described with reference to Fig. 2. Fig. 2 is a plan view of the measurement system 20.

As shown in FIG. 2, the measurement system 20 includes a rail 21, strain gauges 22F and 22R, a measurement device 23, and a processing device 24.

The rail 21 includes a top surface 211. The top surface 211 is the surface with which the wheels 112 come into contact. The front and rear wheels 112, 112 (FIG. 1) of the trolley 10 come into contact with the top surface 211. As shown by the two-dot chain line in FIG. 2, the range of the top surface 211 with which the wheels 112, 112 can come into contact in the width direction (left-right direction) of the rail 21 is called the glare surface 211a. When the trolley 10 moves or runs on the rail 21, the wheels 112, 112 come into contact with the top surface 211 within the glare surface 211a, although there is some variation due to wear of the tread, etc.

The strain gauges 22F and 22R are attached to the top surface 211 of the rail 21. The strain gauges 22F and 22R are attached to the top surface 211, for example, by adhesive. The strain gauges 22F and 22R are arranged at positions shifted in the width direction of the rail 21 from the contact positions of the wheels 112 and 112 (FIG. 1) on the top surface 211. In other words, the strain gauges 22F and 22R are arranged on the top surface 211 offset in the width direction of the rail 21 from the illuminated surface 211a so as not to substantially overlap with the illuminated surface 211a. The strain gauges 22F and 22R are preferably arranged outside the illuminated surface 211a in the left-right direction of the cart 10 (FIG. 1), but may be arranged inside the illuminated surface 211a.

The strain gauges 22F, 22R should not be positioned too far from the illuminated surface 211a. For example, the strain gauges 22F, 22R are positioned in a range that is affected by the Hertzian stress distribution when the wheels 112, 112 come into contact with the illuminated surface 211a next to the strain gauges 22F, 22R.

Strain gauges 22F, 22R are positioned apart from each other in the longitudinal direction (front-to-rear direction) of rail 21 by the reference wheelbase L. Reference wheelbase L is the design value of the wheelbase of the bogie 10 (Figure 1) to be measured, and is a value that is determined in advance at the design stage. In this embodiment, strain gauge 22F is positioned at the front and strain gauge 22R is positioned at the rear in the front-to-rear direction of bogie 10.

Strain gauges 22F, 22R may be a commonly used single-axis gauge or a multi-axis gauge such as a rosette gauge. As strain gauges 22F, 22R, publicly known or commercially available strain gauges can be appropriately selected and used. Typically, strain gauges 22F, 22R are the same type of strain gauge.

The measuring device 23 is a device that is generally used when measuring stress or strain using a strain gauge. The measuring device 23 includes, for example, a bridge box, a strain amplifier, and a data logger. In the measuring device 23, the components such as the bridge box, the strain amplifier, and the data logger may be configured as a single device or may be configured as multiple devices. In other words, the measuring device 23 may be a single device, or may be a collection of multiple devices. The strain occurring in the rail 21 is measured by the strain gauges 22F, 22R and the measuring device 23.

The processing device 24 is connected to the measuring device 23. The processing device 24 may be constantly connected to the measuring device 23 on the network, or may be connected to the measuring device 23 only when necessary. In the example shown in FIG. 2, the processing device 24 is separate from the measuring device 23, but may be configured integrally with the measuring device 23. The processing device 24 acquires output data output by the strain gauges 22F, 22R via the measuring device 23. The processing device 24 may acquire the output data output by the strain gauges 22F, 22R in real time, or may acquire the output data accumulated in the measuring device 23 periodically or irregularly. The processing device 24 performs a predetermined process on the acquired output data to determine the deviation of the wheelbase from the reference wheelbase L. The specific process of the processing device 24 will be described later.

The processing device 24 may be a commonly used computer (e.g., a personal computer). The processing device 24 includes, for example, a central processing unit (CPU), a main memory device, an auxiliary memory device, etc. The processing device 24 may further include input devices such as a mouse, a keyboard, and a touch panel, and an output device such as a display. The processing device 24 may be a dedicated device specially configured for processing the output data of the strain gauges 22F, 22R. The processing device 24 stores, for example, a program for realizing the functions of the processing device 24, and can execute the program in response to a user's operation.

[Measurement method]
Hereinafter, a method for measuring the wheelbase of the bogie 10 using the measurement system 20 will be described. The wheelbase is measured, for example, in a factory or the like when the bogie 10 is maintained. However, the wheelbase may also be measured while the railcar including the bogie 10 is in operation.

Figure 3 is a flowchart showing the measurement method according to this embodiment. As shown in Figure 3, this measurement method includes step S1 of preparing the measurement system 20, step S2 of acquiring output data from the strain gauges 22F and 22R, and step S3 of determining the deviation of the wheelbase of the bogie 10 from the reference wheelbase L.

(Step S1)
4 and 5 are schematic diagrams for explaining the measurement method according to the present embodiment. With reference to Fig. 4 and Fig. 5, in this embodiment, in step S1, two measurement systems 20 are prepared. More specifically, a rail 21 and strain gauges 22F and 22R are provided corresponding to the front and rear wheels 112, 112 arranged on the left side of the cart 10. In addition, a rail 21 and strain gauges 22F and 22R are provided corresponding to the front and rear wheels 112, 112 arranged on the right side of the cart 10.

(Step S2)
In step S2, the cart 10 is moved on the rail 21 on which the strain gauges 22F and 22R are provided. The portion of the rail 21 on which the cart 10 is moved is typically straight, but may be curved. The cart 10 moves on the top surface 211 of the rail 21 so as not to interfere with the strain gauges 22F and 22R. The cart 10 may pass through the strain gauges 22F and 22R, or may stop at or near the installation positions of the strain gauges 22F and 22R. This causes strain in each rail 21. The strain gauges 22F and 22R output this strain as an electric signal via the measuring device 23. The processing device 24 acquires the output data output from the strain gauges 22F and 22R and the measuring device 23.

(Step S3)
The processing device 24 determines the deviation of the wheelbase of the bogie 10 from the reference wheelbase L based on the output data of the strain gauges 22F, 22R at the same time. More specifically, the processing device 24 determines the deviation of the wheelbase from the reference wheelbase L by comparing the output data of the strain gauges 22F, 22R at the same time with the calibration data. The calibration data is acquired in advance before measuring the wheelbase of the bogie 10. The calibration data can be stored in the processing device 24 in advance. Alternatively, the calibration data may be stored in a storage device that is separate from the processing device 24 and accessible by the processing device 24.

Figure 6 is a diagram illustrating the calibration data 30. The calibration data 30 includes information showing the relationship between the distance in the longitudinal direction (front-to-back direction) of the rail 21 from each of the strain gauges 22F, 22R to the contact position of the wheel 112 with the top surface 211 of the rail 21, and the output data of each of the strain gauges 22F, 22R.

As shown in FIG. 6, in the calibration data 30, the value (vertical axis) corresponding to the output data of the strain gauges 22F, 22R is, for example, equivalent strain. This value has a peak when the contact position of the wheel 112 and the installation positions of the strain gauges 22F, 22R are substantially coincident, that is, when the distance in the longitudinal direction of the rail 21 from the strain gauges 22F, 22R to the contact position of the wheel 112 is substantially 0 mm. The value (absolute value) of the vertical axis of the calibration data 30 decreases as the contact position of the wheel 112 moves away from the installation positions of the strain gauges 22F, 22R in the longitudinal direction of the rail 21.

Figure 7 is a schematic diagram for explaining an example of a method for acquiring the calibration data 30. As shown in Figure 7, the calibration data 30 can be acquired using an instrument 40 having a wheel shape on the underside. When acquiring the calibration data 30, for example, a load is applied to the top surface 211 of the rail 21 by the instrument 40, and the resulting strain is measured by the strain gauge 22F. The strain measurement by the strain gauge 22F is performed for each distance in the longitudinal direction of the rail 21 from the strain gauge 22F to the contact position of the instrument 40 with the top surface 211 while moving the instrument 40 in the longitudinal direction of the rail 21, for example, in mm units. This makes it possible to create the calibration data 30 as shown in Figure 6. The calibration data 30 may be created by measuring the strain with the strain gauge 22R instead of the strain gauge 22F. Alternatively, calibration data 30 can be created using rails and strain gauges other than rail 21 and strain gauges 22F, 22R of measurement system 20, and instrument 40. It is preferable that the strain gauges used in this case are the same type as strain gauges 22F, 22R.

However, it is not necessary to use the tool 40 to obtain the calibration data 30. For example, the calibration data 30 can be obtained by a structural simulation using general-purpose structural analysis software.

Returning to Figures 4 and 5, in step S3, when comparing the output data of the strain gauges 22F, 22R with the calibration data 30, the processing device 24 corrects the output data of the strain gauges 22F, 22R so that the load conditions of the cart 10 correspond to the load conditions of the calibration data 30. The processing device 24 corrects the output data of the strain gauges 22F, 22R, for example, so that the peak value of the output data of the strain gauges 22F, 22R matches the peak value of the calibration data 30. For example, if the peak value of the calibration data 30 is 140μ, the magnification of the output data of the strain gauges 22F, 22R is adjusted so that the peak value of the output data of the strain gauges 22F, 22R is also 140μ.

Then, the processing device 24 determines the deviation of the wheelbase from the reference wheelbase L based on the output data of the strain gauges 22F, 22R at the same time. The processing device 24 references the output data (after correction) of the other of the strain gauges 22F, 22R for the time (peak time) when the output data of one of the strain gauges 22F, 22R reaches its peak. The processing device 24, for example, references the output data of the strain gauge 22R at the same time as the peak time t of the strain gauge 22F. The processing device 24 compares the output data of this strain gauge 22R with the calibration data 30 to determine the deviation of the wheelbase from the reference wheelbase L.

In Figures 4 and 5, examples of output data from each of strain gauges 22F, 22R are displayed near the corresponding strain gauges 22F, 22R. In the example shown in Figure 4, the left and right wheelbases of the bogie 10 substantially coincide with the reference wheelbase L. Therefore, on both the left and right sides of the bogie 10, the output data of strain gauge 22R peaks at the same time t as the peak time of strain gauge 22F. Therefore, the deviation of the left and right wheelbases of the bogie 10 from the reference wheelbase L is substantially 0 mm.

On the other hand, in the example shown in FIG. 5, the wheelbase on the left side of the bogie 10 is shorter than the reference wheelbase L, and the wheelbase on the right side is longer than the reference wheelbase L. On the left side of the bogie 10, the output data of the strain gauge 22R does not peak at the same time as the peak time t of the strain gauge 22F. Based on the value of the output data of the strain gauge 22R at that time and the calibration data 30 (FIG. 6), the processing device 24 can obtain the distance d1 in the longitudinal direction of the rail 21 between the contact position with the top surface 211 and the strain gauge 22R for the wheel 112 of the rear wheelset 11R. The distance d1 corresponds to the deviation of the wheelbase on the left side of the bogie 10 from the reference wheelbase L.

Similarly, on the right side of the bogie 10, the output data of the strain gauge 22R does not peak at the same time as the peak time t of the strain gauge 22F. Based on the value of the output data of the strain gauge 22R at that time and the calibration data 30 (Figure 6), the processing device 24 can obtain the distance d2 in the longitudinal direction of the rail 21 between the contact position with the top surface 211 and the strain gauge 22R for the wheel 112 of the rear wheel set 11R. The distance d2 corresponds to the deviation of the wheelbase on the right side of the bogie 10 from the reference wheelbase L.

In the example of FIG. 5, the output data of the strain gauge 22R on the left side of the bogie 10 has already peaked at the peak time t of the strain gauge 22F. In this case, it means that the wheelbase on the left side of the bogie 10 is shorter than the reference wheelbase L. Also, in the example of FIG. 5, the output data of the strain gauge 22R on the right side of the bogie 10 has not yet peaked at the peak time t of the strain gauge 22F. In this case, it means that the wheelbase on the right side of the bogie 10 is longer than the reference wheelbase L. Based on the output data of the strain gauge 22R at times other than the peak time t, the processing device 24 can determine whether the output data of the strain gauge 22R has already peaked or has not yet peaked at the peak time t. Based on this, the processing device 24 can determine whether the wheelbase is longer or shorter than the reference wheelbase L (positive or negative deviation).

The processing device 24 can calculate the left and right wheelbase of the bogie 10 based on the acquired deviation amount and the reference wheelbase L. The processing device 24 calculates the wheelbase of the bogie 10, for example, by adding or subtracting the deviation amount to or from the reference wheelbase L. The processing device 24 may output at least one of the calculated wheelbase and the deviation amount of the wheelbase from the reference wheelbase L to an output device such as a display.

[effect]
According to the measurement system 20 and the measurement method of the present embodiment, the strain gauges 22F, 22R attached to the top surface 211 of the rail 21 can obtain output data indicating strain generated in the rail 21 according to the load applied from the bogie 10 to the top surface 211. In addition, the processing device 24 automatically determines the deviation of the wheelbase of the bogie 10 from the reference wheelbase L based on the output data of the strain gauges 22F, 22R at the same time. Therefore, the actual wheelbase can be measured. Such measurement of the wheelbase can be performed by simply moving the bogie 10 on the top surface 211 of the rail 21. Therefore, the wheelbase can be measured regardless of whether the car body of the rail vehicle is attached to the bogie 10 or not, and there is no particular need to remove the car body from the bogie 10 when measuring the wheelbase. Therefore, the wheelbase can be easily and quickly measured even when the bogie 10 is in its existing state.

In this embodiment, the deviation of the wheelbase of the bogie 10 from the reference wheelbase L is determined using the output data of the strain gauges 22F, 22R at the same time, as well as the calibration data 30 acquired in advance. In this case, even if the strain gauges 22F, 22R are not attached precisely to the specified positions, there is almost no effect on the measurement of the wheelbase, so the wheelbase can be measured more accurately. In addition, if the change over time of the measurement system 20, such as deterioration of the strain gauges 22F, 22R, affects the acquisition of the wheelbase deviation, the effect of the change over time can be eliminated by periodically reacquiring and updating the calibration data 30. This makes it possible to accurately measure the wheelbase over the long term.

In this embodiment, an example is described in which the output data of the strain gauge 22R at the peak time t of the strain gauge 22F is compared with the calibration data 30 to obtain the amount of deviation of the wheelbase from the reference wheelbase L. However, the processing device 24 can obtain the output data of the strain gauges 22F and 22R at the same time other than the peak time t and compare them with the calibration data 30. By referring to the calibration data 30, the processing device 24 can obtain the distance in the longitudinal direction of the rail 21 from the strain gauge 22F to the contact position of the wheel 112 of one axle 11F and the distance in the longitudinal direction of the rail 21 from the strain gauge 22R to the contact position of the wheel 112 of the other axle 11R. The processing device 24 can obtain the amount of deviation of the wheelbase based on these distances, and can calculate the wheelbase from the amount of deviation and the reference wheelbase L.

In this embodiment, rails 21 and strain gauges 22F, 22R are provided corresponding to the front and rear wheels 112, 112 arranged on the left side of the bogie 10, and rails and strain gauges 22F, 22R are provided corresponding to the front and rear wheels 112, 112 arranged on the right side of the bogie 10. Therefore, the deviation of the wheelbase from the reference wheelbase L can be obtained on both the left and right sides of the bogie 10, and the wheelbase can be measured. However, strain gauges 22F, 22R may be provided only on either the left or right side of the bogie 10.

In this embodiment, strain gauges 22F, 22R are used to measure the wheelbase of the bogie 10. Both strain gauges 22F, 22R and the associated measuring device 23 are widely available and can be prepared at relatively low cost. Therefore, the measurement system 20 and measurement method according to this embodiment make it possible to measure the wheelbase at low cost.

The strain gauges 22F, 22R and the measuring device 23 are robust as means for measuring strain, and can be used for, for example, several years to several decades. In this embodiment, the strain gauges 22F, 22R are offset in the width direction of the rail 21 from the contact position of the wheels 112, 112 with the top surface 211, thereby avoiding interference between the strain gauges 22F, 22R and the wheels 112, 112. Therefore, the deterioration of the strain gauges 22F, 22R is due only to aging. Therefore, the measuring system 20 according to this embodiment can be used for a long period of time.

When commonly used strain gauges 22F, 22R and measuring device 23 are used, a resolution of at least about 1 mm can be obtained for the amount of wheelbase deviation. Therefore, according to the measurement system 20 and measurement method of this embodiment, the wheelbase can be measured with high accuracy. If higher resolution is required, the resolution can be improved by changing the arrangement of the strain gauges 22F, 22R, etc. For example, the strain detection sensitivity can be improved by increasing the number of strain gauges.

Second Embodiment
The second embodiment differs from the first embodiment in that the calibration data 30 is not used when measuring the wheelbase. Referring again to Figures 4 and 5, in this embodiment, the processing device 24 acquires the speed of the bogie 10 moving on the rails 21 when performing step S3 (Figure 3) of determining the deviation of the wheelbase of the bogie 10 from the reference wheelbase L. The speed of the bogie 10 may be measured by a speedometer or the like separate from the processing device 24. The speed of the bogie 10 can also be calculated backwards from the output data of the strain gauges 22F, 22R.

The processing device 24 determines the deviation of the wheelbase of the bogie 10 from the reference wheelbase L based on the time (peak time) when a peak occurs in the output data of the strain gauge 22F and the time (peak time) when a peak occurs in the output data of the strain gauge 22R.

As shown in the example of FIG. 4, when the peak time t of strain gauge 22F and the peak time of strain gauge 22R are substantially the same, the deviation of the wheelbase from the reference wheelbase L is substantially 0 mm. On the other hand, as shown in the example of FIG. 5, when the peak time t of strain gauge 22F and the peak time of strain gauge 22R are different, the wheelbase of the bogie 10 is deviated from the reference wheelbase L. If the peak time of the rear strain gauge in the direction of movement of the bogie 10 is earlier than the peak time of the front strain gauge among strain gauges 22F and 22R, it means that the wheelbase of the bogie 10 is shorter than the reference wheelbase L. If the peak time of the rear strain gauge in the direction of movement of the bogie 10 is later than the peak time of the front strain gauge among strain gauges 22F and 22R, it means that the wheelbase of the bogie 10 is longer than the reference wheelbase L. The processing device 24 can calculate the deviation of the wheelbase from the reference wheelbase L based on the difference in peak time between the strain gauges 22F and 22R and the speed of the bogie 10.

The measurement system 20 and measurement method according to this embodiment, like the measurement system 20 and measurement method according to the first embodiment, can easily and quickly measure the wheelbase of the bogie 10, regardless of whether it is in a present state or not.

Third Embodiment
In the first and second embodiments, the top surface 211 of the rail 21 is not particularly processed. On the other hand, in the third embodiment, the top surface 211 of the rail 21 is processed. FIG. 8 is a cross-sectional view (cross-section on a plane parallel to the width direction) of the rail 21 in this embodiment. As shown in FIG. 8, in the rail 21 in this embodiment, the top surface 211 includes a recess 211b. The recess 211b is disposed at a position shifted in the width direction of the rail 21 from the contact position of the wheel on the top surface 211. The strain gauge 22F is disposed in the recess 211b. This makes it possible to more reliably avoid interference between the strain gauge 22F and the wheel.

Although not shown in the figure, the recess 211b can also be provided at a position on the top surface 211 of the rail 21 that corresponds to the strain gauge 22R (Figure 2). In this case, the strain gauges 22F and 22R are each disposed within the recess 211b. This makes it possible to more reliably avoid interference between the strain gauges 22F and 22R and the wheels.

However, it is also possible to provide a recess 211b at a position on the top surface 211 of the rail 21 that corresponds to only one of the strain gauges 22F, 22R, and to place only one of the strain gauges 22F, 22R in the recess 211b.

Fourth Embodiment
In the fourth embodiment, the top surface 211 of the rail 21 is also machined. Fig. 9 is a cross-sectional view (a cross-section parallel to the width direction) of the rail 21 in this embodiment. In Fig. 9, the strain gauges 22F and 22R are not distinguished from each other and are simply referred to as the strain gauge 22.

As shown in FIG. 9, in the rail 21 of this embodiment, the top surface 211 has a convex shape when viewed in cross section of the rail 21. The convex shape of the top surface 211 does not need to be formed over the entire length of the rail 21, but only needs to be formed in at least the portion where the strain gauge 22 is affixed. The wheel comes into contact with the apex of the top surface 211 having a convex shape near the strain gauge 22.

Figure 10 is a plan view of the measurement system 20 according to this embodiment. Referring to Figure 10, in the area of the top surface 211 that has a convex shape, the length of the illuminated surface 211a in the width direction of the rail 21 is smaller than in the area that does not have a convex shape. That is, in the area of the top surface 211 that has a convex shape, the contact position of the wheel is controlled so that the contact position of the wheel with the top surface 211 does not vary in the width direction of the rail 21. Therefore, it is possible to avoid interference of the wheel with the strain gauges 22F, 22R due to variation in the contact position of the wheel.

In this embodiment, the shape of the top surface 211 is adjusted to control the wheel contact position so that variation in the wheel contact position is less likely to occur. This allows the strain gauges 22F, 22R to be closer to the wheel contact position, improving the detection sensitivity and detection accuracy of the strain gauges 22F, 22R when measuring the wheelbase. Furthermore, it is also possible to suppress errors in the output data of the strain gauges 22F, 22R and the measurement of the wheelbase due to variation in the wheel contact position.

Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments, and various modifications are possible without departing from the spirit of the present disclosure.

In each of the above embodiments, a single strain gauge 22F is provided on the top surface 211 of the rail 21 corresponding to the wheel set 11F, and a single strain gauge 22R is provided corresponding to the wheel set 11R. However, two or more strain gauges may be provided for each wheel set. For example, as shown in FIG. 11, two strain gauges 221F, 222F corresponding to the front wheel set 11F (FIG. 1) may be attached to the top surface 211, and two strain gauges 221R, 222R corresponding to the rear wheel set 11R (FIG. 1) may be attached.

In the example shown in FIG. 11, the strain gauges 221F and 222F on the axle 11F side are arranged on either side of a reference line A1 extending in the width direction of the rail 21. In a plan view of the rail 21, it is preferable that the strain gauges 221F and 222F are arranged symmetrically with respect to the reference line A1. On the other hand, the strain gauges 221R and 222R on the axle 11R side are arranged on either side of a reference line A2 extending in the width direction of the rail 21. In a plan view of the rail 21, it is preferable that the strain gauges 221R and 222R are arranged symmetrically with respect to the reference line A2. The distance between the reference lines A1 and A2 in the longitudinal direction of the rail 21 coincides with the reference wheelbase L. In addition, the distance between the strain gauges 221F and 221R and the distance between the strain gauges 222F and 222R in the longitudinal direction of the rail 21 also coincide with the reference wheelbase L.

In this way, when two or more strain gauges 221F, 222F are provided corresponding to the wheel set 11F, and two or more strain gauges 221R, 222R are provided corresponding to the wheel set 11R, the amount of information acquired by the processing device 24 increases. Therefore, the wheelbase can be measured more accurately. The measurement system 20 shown in FIG. 11 may determine the amount of deviation in the wheelbase using calibration data as in the first embodiment, or may determine the amount of deviation in the wheelbase without using calibration data as in the second embodiment.

The measurement system 20 in each of the above embodiments may be provided with strain gauges other than the strain gauges 22F, 22R, 221F, 222F, 221R, and 222R. For example, the measurement accuracy of the wheelbase can be improved by providing the measurement system 20 with a strain gauge for canceling out strain in an unnecessary direction.

10: Cart 112: Wheels 20: Measurement system 21: Rail 211: Top surface 211b: Recess 22, 22F, 22R, 221F, 222F, 221R, 222R: Strain gauge 24: Processing device 30: Calibration data

Claims (6)

A measuring system for measuring the wheelbase of a bogie for a railway vehicle, comprising:
A rail including a top surface with which the front and rear wheels of the bogie come into contact;
A first strain gauge is disposed at a position shifted in the width direction of the rail from a contact position of the wheel on the top surface and attached to the top surface;
a second strain gauge that is disposed at a position shifted in the width direction from a contact position of the wheel on the top surface and is disposed away from the first strain gauge in the longitudinal direction of the rail by a design value of the wheelbase of the bogie, and is affixed to the top surface;
a processing device that acquires output data outputted from the first strain gauge and the second strain gauge in response to a load applied from the dolly to the top surface;
Equipped with
The processing device determines a deviation of the wheelbase of the bogie from the design value based on output data of the first strain gauge and the second strain gauge at the same time, or based on the occurrence times of peaks in the output data of the first strain gauge and the second strain gauge. 2. The measurement system of claim 1,
the processing device determines a deviation of the wheelbase of the bogie from the design value based on output data of the first strain gauge and the second strain gauge at the same time and calibration data acquired in advance;
The calibration data includes:
A measurement system including information indicating a relationship between a distance in the longitudinal direction from each of the first strain gauge and the second strain gauge to a contact position of the wheel with respect to the top surface and output data of each of the first strain gauge and the second strain gauge. 3. The measurement system according to claim 1 or 2,
The top surface includes at least one recess that is disposed at a position shifted in the width direction from a contact position of the top surface with the wheel,
At least one of the first strain gauge and the second strain gauge is disposed within the recess. A measurement system according to any one of claims 1 to 3,
A measurement system, wherein at least one of a portion of the top surface to which the first strain gauge is attached and a portion of the top surface to which the second strain gauge is attached has a convex shape when viewed in a cross section of the rail. A measurement system according to any one of claims 1 to 4,
The rail, the first strain gauge, and the second strain gauge are provided in correspondence with front and rear wheels arranged on the left side of the carriage,
a measurement system, the rail, the first strain gauge, and the second strain gauge being provided corresponding to front and rear wheels arranged on a right side of the bogie. A method for measuring the wheelbase of a bogie for a railway vehicle, comprising the steps of:
A step of preparing a rail including a top surface, a first strain gauge attached to the top surface, and a second strain gauge attached to the top surface at a distance from the first strain gauge in a longitudinal direction of the rail by a design value of the wheelbase of the bogie;
moving the dolly on the top surface so as not to interfere with the first strain gauge and the second strain gauge, and acquiring output data outputted by the first strain gauge and the second strain gauge;
determining a deviation of a wheelbase of the bogie from the design value based on output data of the first strain gauge and the second strain gauge at the same time or on a time when a peak occurs in each of the output data of the first strain gauge and the second strain gauge;
A measurement method comprising:

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