Lateral pressure measuring device and lateral pressure measuring method

Abstract

This invention provides a lateral pressure measuring device and method that can accurately calculate continuous lateral pressure with a small number of channels. [Solution] The lateral pressure measuring device 10 comprises at least two asymmetric bridge circuits equipped with strain gauges 60 mounted at asymmetric positions on either side of the rotation center of the wheel 40, a symmetric bridge circuit equipped with strain gauges 60 mounted at symmetric positions on either side of the rotation center, and a calculation unit 120. The calculation unit 120 calculates the lateral pressure based on the inverse of the lateral pressure sensitivity vector, which is orthogonal to the proportionality constant vector of the wheel load cross sensitivity and / or the front and rear tangential force, in the output sensitivity characteristics of the asymmetric bridge circuit which change according to the wheel load and the front and rear tangential force. Furthermore, for outputs from the asymmetric bridge circuit relating to singularities where the directions of the lateral pressure sensitivity vector and the wheel load cross sensitivity vector coincide, the calculation unit 120 cancels out the singularity based on the output from the symmetric bridge circuit, which has a different cross sensitivity ratio than the asymmetric bridge circuit.

Description

Technical Field

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[0001] The present invention relates to a lateral pressure measuring device and a lateral pressure measuring method.

Background Art

[0002] In order to evaluate the running safety of railway vehicles, a method of measuring the contact force between wheels and rails using a dedicated axle with a large number of strain gauges attached to wheels called PQ axles is known. On the other hand, if it is possible to measure the contact position in addition to the contact force, it may contribute to elucidating the phenomena related to the contact between wheels and rails and constructing a more in-depth evaluation of running safety.

[0003] In addition, in conventional PQ axles, an error occurs in the lateral pressure measurement result according to the magnitude of the wheel load and the shift amount of the contact position in the left-right direction. However, if the contact position can be measured, this error can be corrected.

[0004] Based on the above background, a method of measuring the contact position has been proposed by attaching a strain gauge for measuring the contact position to a PQ axle (Non-Patent Documents 1, 2, 3). In addition, a method of extracting contact position information based on the change in its frequency characteristics by using a plurality of lateral pressure measurement bridge circuits in combination has also been proposed (Non-Patent Document 4). Furthermore, as a related technique, a method of correcting a part of the error generated in the lateral pressure measurement result while having hardware equivalent to a conventional PQ axle has also been proposed (Non-Patent Document 5).

[0005] In the methods of Non-Patent Documents 1, 2, and 3, a strain gauge for measuring force and a strain gauge for measuring the contact position must be attached independently, and there is a problem that the labor required for manufacturing a PQ axle is large.

[0006] In addition, in the method of Non-Patent Document 4, there is a problem that the sensitivity to the contact position is small, and the obtained contact position information is the average value per wheel rotation, and dynamic information is lost.

[0007] Furthermore, the method described in Non-Patent Document 5 focuses only on the effect of "correcting measurement errors of lateral pressure" among the effects of contact position measurement described in the background technology, and does not allow for the acquisition of the contact position itself.

[0008] Based on these background technologies, prior art has proposed a method for measuring lateral pressure on PQ axles in a bridge circuit, where strain gauges on the opposite side of the axle from a given strain gauge, which are normally combined into a single bridge circuit, are separated from the bridge circuit of that strain gauge, thereby constructing four separate lateral pressure measuring bridge circuits with phases differing by 90 degrees each (hereinafter referred to as an asymmetric axle bridge circuit) (Non-Patent Literature 6). Non-Patent Literature 6 shows that asymmetric axle bridge circuits reduce the influence of wheel load crossover sensitivity in lateral pressure measuring bridge circuits. On the other hand, as a method for evaluating driving safety, a method is also common in which changes in strain sensitivity to force in the circumferential direction of the wheel are corrected using a wheel rotation angle sensor, and periodic strain signals are converted into continuous contact force information (Non-Patent Literature 7). [Prior art documents] [Non-patent literature]

[0009] [Non-Patent Document 1] Kanehara, Ohno. "Development of a continuous wheel-rail contact position measurement device for elucidating the derailment mechanism," JR EAST Technical Review No. 3. [Non-Patent Document 2] Ozawa, et al. "A method for determining the contact position between the wheel and rail using strain analysis of the wheel plate," J-RAIL2018, No.3211, 2018. [Non-Patent Document 3] Noguchi. "Examination of a Measurement Method for Wheel / Rail Contact Position," J-RAIL2019, No. S6-1-4, 2019. [Non-Patent Document 4] Honjo, et al. "A contact position information extraction method based on frequency analysis of PQ wheelset utilizing bending and shear strain," Transactions of the Japan Society of Mechanical Engineers, DOI: 10.1299 / transjsme.22-00128, 2022. [Non-Patent Document 5] Honjo, et al. "Correction Method for Lateral Pressure Measurement Data Between Wheels and Rails Based on Estimation of the Lower Limit of the Load Center Position," Dynamics & Design Conference 2022, Paper No. 515, 2022. [Non-Patent Document 6] Hondō, "Effect of reducing the cross-sectional sensitivity ratio by axle asymmetry of the bridge circuit in a PQ wheelset utilizing shear strain (verification by numerical analysis)," Dynamics & Design Conference 2022, Paper No. 520, 2023. [Non-Patent Document 7] Hiroaki Ishida, Masaki Matsuo, Kazuhiko Tezuka, and Kenji Ueki, "A New Continuous Measurement Method for Wheel Load, Lateral Pressure, and Derailment Coefficient of Railway Vehicles (Development of a Measurement Device)," Transactions of the Japan Society of Mechanical Engineers, Series C, Vol. 63, No. 614 (1997), pp. 3417-3423. [Overview of the project] [Problems that the invention aims to solve]

[0010] By the way, the configuration in Non-Patent Document 6 has the problem that it has many systems of asymmetrical bridge circuits, which increases the number of channels accordingly.

[0011] This invention has been made in view of the above circumstances, and aims to provide a lateral pressure measuring device and a lateral pressure measuring method that can accurately calculate continuous lateral pressure with a small number of channels. [Means for solving the problem]

[0012] [1] In order to solve the above problems, according to a first aspect of the present invention, a lateral pressure measuring device for measuring the lateral pressure between a wheel of a railway vehicle and a rail, wherein the wheel has a rim portion provided on the outer edge and having a tread surface formed thereon, a hub portion provided in the center and to which an axle is attached, and a plate portion provided between the rim portion and the hub portion, and the lateral pressure measuring device comprises at least two asymmetric bridge circuits equipped with strain gauges mounted at asymmetric positions on either side of the rotation center of the wheel, a symmetric bridge circuit equipped with strain gauges mounted at symmetric positions on either side of the rotation center, at least two asymmetric bridge circuits, and a symmetric bridge circuit A lateral pressure measuring device is provided, comprising: a calculation unit that performs calculations based on the output of; the calculation unit calculates the lateral pressure based on the inverse of the lateral pressure sensitivity vector orthogonal to the proportionality constant vector of the wheel load cross sensitivity and / or the front and rear tangential force in the output sensitivity characteristics of an asymmetric bridge circuit that changes according to the wheel load between the wheel and the rail and the front and rear tangential force of the wheel; and for outputs from the asymmetric bridge circuit relating to singularities where the direction of the lateral pressure sensitivity vector and the wheel load cross sensitivity vector coincides, the calculation unit performs calculations to cancel out the singularities based on the output from a symmetric bridge circuit whose cross sensitivity ratio is different from that of the asymmetric bridge circuit.

[0013] [2] In addition, in order to solve the above problems, according to a second aspect of the present invention, a lateral pressure measuring method for measuring the lateral pressure between the wheel and rail of a railway vehicle, wherein the wheel has a rim portion provided on the outer edge and having a tread formed thereon, a hub portion provided in the center and to which an axle is attached, and a plate portion provided between the rim portion and the hub portion, and the lateral pressure measuring device for carrying out the lateral pressure measuring method comprises at least two asymmetric bridge circuits equipped with strain gauges mounted at asymmetric positions on either side of the rotation center of the wheel, and a symmetric bridge circuit equipped with strain gauges mounted at symmetric positions on either side of the rotation center, and at least two asymmetric bridge circuits A method for measuring lateral pressure is provided, characterized in that calculation processing is performed based on the output of the road and a symmetric bridge circuit, and in the calculation processing, the lateral pressure is calculated based on the inverse of the lateral pressure sensitivity vector orthogonal to the proportionality constant vector of the wheel load cross sensitivity and / or the front and rear tangential force in the output sensitivity characteristics of the asymmetric bridge circuit which changes according to the wheel load between the wheel and the rail and the front and rear tangential force of the wheel, and for outputs from the asymmetric bridge circuit related to singularities where the direction of the lateral pressure sensitivity vector and the wheel load cross sensitivity vector coincide, calculations are performed to cancel out the singularities based on the output from a symmetric bridge circuit whose cross sensitivity ratio is different from that of the asymmetric bridge circuit. [Effects of the Invention]

[0014] According to the present invention, it is possible to provide a lateral pressure measuring device and a lateral pressure measuring method that can accurately calculate continuous lateral pressure with a small number of channels. [Brief explanation of the drawing]

[0015] [Figure 1] This figure shows a schematic configuration of a lateral pressure measuring device according to one embodiment of the present invention. [Figure 2] Figure 1 shows the PQ wheels used in the lateral pressure measuring device, and also illustrates the relationship between wheel load P, lateral pressure Q, and longitudinal tangential force T. [Figure 3]It shows the configuration of the wheel used in the lateral pressure measuring device shown in FIG. 1, and is a diagram showing the arrangement of strain gauges constituting the bridge circuit for lateral pressure measurement according to the first configuration example. (a) is a view of the wheel seen from the outside in the axle direction and the outside in the wheel width direction, and (b) and (b) are cross-sectional views taken along the arrow in the 1-1 part and the 2-2 part of (a), respectively. [Figure 4] It is a diagram showing the configuration of the first asymmetric bridge circuit among the bridge circuits for lateral pressure measurement according to the first configuration example. [Figure 5] It is a diagram showing the configuration of the second asymmetric bridge circuit among the bridge circuits for lateral pressure measurement according to the first configuration example. [Figure 6] It is a diagram showing the configuration of the symmetric bridge circuit among the bridge circuits for lateral pressure measurement according to the first configuration example. [Figure 7] (a) is a schematic diagram showing the lateral pressure sensitivity characteristic (lateral pressure sensitivity vector) and the wheel load cross-sensitivity characteristic (wheel load cross-sensitivity vector) when the bridge output space is formed by the outputs of two systems of bridge circuits. (b) is a diagram showing the state where the bridge output vector composed of the two systems of bridge circuits in the schematic diagram of (a) is projected in the lateral pressure sensitivity direction. (c) is a diagram for explaining the error due to the projected component of the wheel load cross-sensitivity in the new continuous method of (b). [Figure 8] (a) is a diagram showing the orthogonal complement space orthogonal to the wheel load cross-sensitivity vector and the cross-sensitivity orthogonal weighting function in which the influence of the wheel load is removed by projection onto the orthogonal complement space in the bridge output space shown in FIG. 7(a). (b) is a diagram showing a state where the cross-sensitivity orthogonal weighting function of (a) cannot be applied. [Figure 9] It is a diagram showing the relationship between the circumferential direction load position and the lateral pressure sensitivity when analyzed by the finite element method using three systems of bridge circuits constituting the bridge circuit for lateral pressure measurement according to the first configuration example. [Figure 10]When analyzing by the finite element method using three bridge circuits that constitute the bridge circuit for lateral pressure measurement according to the first configuration example, it is a diagram showing the relationship between the circumferential loading position and the cross sensitivity of wheel load in the left - right direction (wobble direction) loading position y, where (a) shows the case where the loading position y is at +20 mm (flange side), (b) shows the case where the loading position y is at 0 mm (tread center), and (c) shows the case where the loading position y is at -20 mm (anti - flange side). [Figure 11] When analyzing by the finite element method using three bridge circuits that constitute the bridge circuit for lateral pressure measurement according to the first configuration example, it is a diagram showing the relationship between the circumferential loading position and the cross sensitivity of tangential force in the front - rear direction in the left - right direction (wobble direction) loading position y, where (a) shows the case where the loading position y is at +20 mm (flange side), (b) shows the case where the loading position y is at 0 mm (tread center), and (c) shows the case where the loading position y is at -20 mm (anti - flange side). [Figure 12] When analyzing by the finite element method using the first asymmetric bridge circuit and the second asymmetric bridge circuit that constitute the bridge circuit for lateral pressure measurement according to the first configuration example, it is a diagram showing the relationship between the circumferential loading position and the weight, where (a) shows the weighting function F11 and (b) shows the weighting function F12. [Figure 13] When analyzing by the finite element method using the first asymmetric bridge circuit and the second asymmetric bridge circuit that constitute the bridge circuit for lateral pressure measurement according to the first configuration example, it is a diagram showing the relationship between the circumferential loading position and the weight, where (a) shows the weighting function F13 and (b) shows the weighting function F14. [Figure 14] It shows the configuration of the wheel used in the lateral pressure measuring device shown in Fig. 1 and shows the arrangement of strain gauges that constitute the bridge circuit for lateral pressure measurement according to the second configuration example. (a) is a view of the wheel seen from the outside in the axle direction and the vehicle width direction, and (b) and (b) are cross - sectional views taken along the arrow of part 1 - 1 and part 2 - 2 of (a), respectively. [Figure 15] It is a diagram showing the configuration of the first asymmetric bridge circuit among the bridge circuits for lateral pressure measurement according to the second configuration example. [Figure 16] This figure shows the configuration of the second asymmetric bridge circuit, which is one of the bridge circuits for measuring lateral pressure according to the second configuration example. [Figure 17] This figure shows the configuration of a symmetrical bridge circuit, which is one of the bridge circuits for measuring lateral pressure according to the second configuration example. [Figure 18] This figure shows the relationship between the circumferential loading position and the lateral pressure sensitivity when analyzed using the finite element method with three bridge circuits that constitute the bridge circuit for lateral pressure measurement according to the second configuration example. [Figure 19] The figure shows the relationship between the circumferential loading position and the wheel load crossover sensitivity at the respective left-right (sleeper direction) loading positions y, when the finite element method was used to analyze the bridge circuit for lateral pressure measurement according to the second configuration example. (a) shows the case where the loading position y is at +20 mm (flange side), (b) shows the case where the loading position y is at 0 mm (center of the tread), and (c) shows the case where the loading position y is at -20 mm (opposite flange side). [Figure 20] The figure shows the relationship between the circumferential loading position and the front-to-back tangential force crossing sensitivity at the respective left-to-right (sleeper direction) loading positions y, when the finite element method was used to analyze the bridge circuit for lateral pressure measurement according to the second configuration example. (a) shows the case where the loading position y is at +20 mm (flange side), (b) shows the case where the loading position y is at 0 mm (center of the tread), and (c) shows the case where the loading position y is at -20 mm (opposite flange side). [Figure 21] The first and second asymmetric bridge circuits, which constitute the bridge circuit for measuring lateral pressure according to the second configuration example, were analyzed using the finite element method. The figures show the relationship between the circumferential loading position and the weights, with (a) showing the weighting function F21 and (b) showing the weighting function F22. [Figure 22]The first and second asymmetric bridge circuits, which constitute the bridge circuit for measuring lateral pressure according to the second configuration example, were analyzed using the finite element method. The figures show the relationship between the circumferential loading position and the weights, with (a) showing the weighting function F23 and (b) showing the weighting function F24. [Modes for carrying out the invention]

[0016] Hereinafter, a lateral pressure measuring device 10 and a lateral pressure measuring method according to one embodiment of the present invention will be described with reference to the drawings.

[0017] [1. Configuration of the lateral pressure measuring device 10] Figure 1 shows a schematic configuration of the lateral pressure measuring device 10 according to this embodiment. The lateral pressure measuring device 10 of this embodiment includes a PQ wheelset 20, a slip ring device 100, a strain signal processing unit 110, and a calculation unit 120.

[0018] [1-1. Regarding PQ Wheelset 20] Figure 2 is a perspective view showing the PQ wheelset 20, which is used for measuring the derailment coefficient, as part of the lateral pressure measuring device 10 shown in Figure 1, along with the wheel load P and lateral pressure Q.

[0019] Here, the PQ wheelset 20 is a wheelset used to measure the wheel load P, lateral pressure Q, and longitudinal tangential force T acting between the wheel 40 and the rail R using strain gauges 60 attached to the wheel 40, and the wheelset itself can be considered as a load cell. This PQ wheelset 20 comprises a wheelset 30 and strain gauges 60.

[0020] As shown in Figure 2, wheel load P is the radial force on the wheel 40 from the rail R, lateral force Q is the axial force on the axle 50 from the rail R on the wheel 40, and longitudinal tangential force T is the force on the wheel 40 from the rail R in the direction of the rail R's extension. When the wheel 40 is not tilted in the vertical direction, wheel load P is the vertical force, and lateral force Q is the lateral force connecting the pair of rails R.

[0021] As shown in Figure 1, the wheelset 30 is constructed by press-fitting the axle 50 near both ends into a pair of left and right wheels 40 and then fixing it in place. As shown in Figure 2, the wheel 40 is a wheel in which the hub portion 41, rim portion 42, tread surface 43, flange 44, and plate portion 45 are integrally formed. Of these, the hub portion 41 is the part located in the radial center of the wheel 40 and is the part into which the axle 50 is fixed after press-fitting. The hub portion 41 is formed to have a greater thickness in the direction of the rotation axis (the axial direction of the axle 50) than the plate portion 45, and a hub hole 41a is formed in its center for press-fitting the axle 50.

[0022] Furthermore, the rim portion 42 is a ring-shaped part provided on the outer edge of the wheel 40, and is the part that comes into contact with the rail R and rolls, forming the so-called tire portion. For this reason, the rim portion 42 is provided with a larger axial dimension than the plate portion 45.

[0023] The tread surface 43 is the portion located on the outer circumferential surface of the rim portion 42 that contacts the upper surface of the rail R. This tread surface 43 is formed to have a predetermined tread gradient that decreases in diameter towards the axial center of the axle 50, in order to allow the left and right wheels to pass through curves smoothly by creating a difference in turning radius when passing through curves.

[0024] Furthermore, the flange 44 is a portion that protrudes outward from near the inner end of the tread surface 43. This flange 44 is a portion that restricts the axial movement of the wheel 40 relative to the rail R in order to prevent the wheel 40 from coming off the rail R.

[0025] The plate portion 45 is a substantially flat plate-shaped part that connects the outer circumferential surface of the hub portion 41 and the inner circumferential surface of the rim portion 42.

[0026] In addition, the plate portion 45 is provided with multiple bolt holes (not shown) as well as multiple (eight in Figure 3) measuring holes 47. The multiple measuring holes 47 are holes for positioning strain gauges 60 to measure the wheel load P. These measuring holes 47 are located in the radial direction of the wheel 40, midway between the inner peripheral edge of the rim portion 42 and the outer peripheral edge of the hub portion 41.

[0027] In the following explanation, the multiple measurement holes 47 are numbered sequentially in a clockwise direction, and the strain gauges 60 described later are also numbered accordingly. Specifically, the measurement hole 47 located at 12 o'clock (0 degrees) relative to the clock face is designated as measurement hole 47-1. The measurement hole 47 located between 1 o'clock (30 degrees) and 2 o'clock (60 degrees) (45 degrees) is designated as measurement hole 47-2. Similarly, the measurement holes 47 located at 3 o'clock (90 degrees), between 4 o'clock (120 degrees) and 5 o'clock (150 degrees) (135 degrees), at 6 o'clock (180 degrees), between 7 o'clock (210 degrees) and 8 o'clock (240 degrees) (225 degrees), at 9 o'clock (270 degrees), and between 10 o'clock (300 degrees) and 11 o'clock (330 degrees) (315 degrees) are designated as measurement holes 47-3, 47-4, 47-5, 47-6, 47-7, and 47-8, respectively.

[0028] [1-2. About Strain Gauge 60] Next, the strain gauge 60 will be described. Figure 3 shows the configuration of the wheel used in the lateral pressure measuring device 10, and the arrangement of the strain gauge 60 that constitute the bridge circuit Q1 for lateral pressure measurement according to the first configuration example. (a) is a view of the wheel 40 from the outside in the axle axis direction and the width direction, and (b) and (b) are cross-sectional views taken along the arrow 1-1 and 2-2 of (a), respectively. The strain gauge 60 is attached to the inner circumferential surface of the measuring hole 47. A triaxial strain gauge and a uniaxial strain gauge can be used as the strain gauge 60.

[0029] In Figure 3, the dashed lines indicate the strain gauges 60 corresponding to bridge circuit Q11, second asymmetric bridge circuit Q12, and symmetric bridge circuit Q13, respectively, within the bridge circuit Q1 for lateral pressure measurement in the first configuration example.

[0030] Incidentally, among the strain gauges 60, the triaxial strain gauge measures strain in three different directions. Of these three-axis strain gauges, the two orthogonal strain gauges are used to measure shear strain and calculate the lateral pressure Q. The central, non-orthogonal strain gauge of the three-axis strain gauge is used to measure the wheel load P and is not used for the conversion of the lateral pressure Q. Therefore, if it is not necessary to measure the wheel load P, a two-axis strain gauge can be used instead of the triaxial strain gauge 60.

[0031] In this embodiment, the three-axis strain gauges are strain gauges 61A, 61B, 63A, 63B, 65A, 65B, 67A, and 67B from the strain gauge 60. Also, as shown in Figure 3, the strain gauge whose head (in the axial direction toward the outer diameter of the wheel) is tilted toward the flange 44 is designated as sub-number 3, the strain gauge for measuring the central wheel load is designated as sub-number 2, and the strain gauge whose head is tilted in the opposite direction from the flange 44 (anti-flange direction) is designated as sub-number 1.

[0032] Furthermore, since single-axis strain gauges measure strain in the direction of the wheel load P, strain gauges are only provided for one direction of the wheel load P. In other words, single-axis strain gauges correspond to strain gauge sub-number 2 of the three-axis strain gauges. In the first configuration example, the single-axis strain gauges correspond to strain gauges 62A, 62B, 64A, 64B, 66A, 66B, 68A, and 68B of the strain gauge 60.

[0033] Each strain gauge related to sub-number 2 constitutes a wheel load bridge circuit in a known continuous wheel load measuring device. For example, strain gauges 61A-2, 62A, 66B, 65B-2, 62B, 61B-2, 65A-2, and 66A are connected sequentially in a ring shape (not shown).

[0034] [1-3. Regarding the bridge circuit Q1 for lateral pressure measurement in the first configuration example] Next, we will describe the bridge circuit Q1 for measuring lateral pressure, which is one of the bridge circuits for measuring lateral pressure and relates to the first configuration example.

[0035] As shown in Figures 4 to 6, the bridge circuit Q1 for measuring lateral pressure according to the first configuration example includes a first asymmetric bridge circuit Q11, a second asymmetric bridge circuit Q12, and a symmetric bridge circuit Q13.

[0036] The first asymmetric bridge circuit Q11 and the second asymmetric bridge circuit Q12 are two sets of axially asymmetric bridge circuits whose sensitivity characteristics have a phase difference of 180 degrees from each other. The symmetric bridge circuit Q13 is an axially symmetric bridge circuit whose phase is 90 degrees different from both the first asymmetric bridge circuit Q11 and the second asymmetric bridge circuit Q12. The lateral pressure measuring device 10 of this embodiment uses these three sets of bridge circuits Q11 to Q13, which are configured for measuring lateral pressure and contact position.

[0037] Figure 4 shows the configuration of the first asymmetric bridge circuit Q11, which is part of the bridge circuit Q1 for measuring lateral pressure according to the first configuration example. As shown in Figure 4, the first asymmetric bridge circuit Q11 is constructed by sequentially connecting strain gauges 61A-1, 61A-3, 61B-1, and 61B-3 in a ring. The output of this first asymmetric bridge circuit Q11 is the voltage between strain gauges 61A-1 and 61A-3 and between strain gauges 61B-1 and 61B-3.

[0038] Figure 5 shows the configuration of the second asymmetric bridge circuit Q12, which is part of the bridge circuit Q1 for measuring lateral pressure according to the first configuration example. As shown in Figure 5, the second asymmetric bridge circuit Q12 is constructed by sequentially connecting strain gauges 65A-1, 65A-3, 65B-1, and 65B-3 in a ring. The output of this first asymmetric bridge circuit Q11 is the voltage between strain gauges 65A-1 and 65A-3, and between strain gauges 65B-1 and 65B-3.

[0039] Figure 6 shows the configuration of the symmetric bridge circuit Q13, which is part of the bridge circuit Q1 for measuring lateral pressure according to the first configuration example. In the first configuration example, the symmetric bridge circuit Q13 uses a triaxial strain gauge instead of a uniaxial strain gauge. However, the symmetric bridge circuit Q13 may also use a uniaxial strain gauge instead of a triaxial strain gauge.

[0040] As shown in Figure 6, the symmetric bridge circuit Q13 is constructed by sequentially connecting strain gauges 63A-3, 63B-3, 67A-3, 67B-3, 67B-1, 67A-1, 63B-1, and 63A-1 in a ring. The output of this symmetric bridge circuit Q13 is the voltage between strain gauges 63B-3 and 67A-3, and between strain gauges 67A-1 and 63B-1.

[0041] [1-4. Regarding the slip ring device 100, strain signal processing unit 110, and calculation unit 120]

[0042] The outputs of the bridge circuits Q11 to Q13 are input to the slip ring device 100. The slip ring device 100 outputs a signal to the strain signal processing unit 110.

[0043] The distortion signal processing unit 110 receives the outputs of the bridge circuits Q11 to Q13 as input. The distortion signal processing unit 110 amplifies the input signals and performs signal processing such as AD conversion, and then transmits a predetermined signal to the calculation unit 120.

[0044] Furthermore, various calculations, including the weighting function described later, are performed in the calculation unit 120.

[0045] [2. Significance of using the first asymmetric bridge circuit Q11, the second asymmetric bridge circuit Q12, and the symmetric bridge circuit Q13] Next, we will explain the significance of using the first asymmetric bridge circuit Q11, the second asymmetric bridge circuit Q12, and the symmetric bridge circuit Q13. In explaining this significance, we will first describe the graphical interpretation of the cross-sensitivity orthogonal weighting function for the first asymmetric bridge circuit Q11 and the second asymmetric bridge circuit Q12. In this graphical interpretation, the space consisting of the outputs of multiple bridge circuits is called the "bridge output space." For example, if there are two lateral pressure measurement bridge circuits, the bridge output space is a two-dimensional vector space; if there are four circuits, it is a four-dimensional vector space. Here, we will consider the case where the bridge output space is two-dimensional.

[0046] Figure 7(a) is a schematic diagram showing the lateral pressure sensitivity characteristics (lateral pressure sensitivity vector) and wheel load crossing sensitivity characteristics (wheel load crossing sensitivity vector) when a bridge output space is formed by the outputs of two bridge circuits; (b) is a diagram showing the state in the schematic diagram of (a) where the bridge output vector composed of the two bridge circuits described above is projected into the lateral pressure sensitivity direction; and (c) is a diagram for explaining the error due to the projection component of the wheel load crossing sensitivity in the new continuous method of (b).

[0047] The sensitivity and crossover sensitivity characteristics of the PQ wheelset are determined by optimizing the bridge circuit configuration, thereby establishing a baseline in the bridge output space as shown in Figure 7(a). In this case, for example, the bridge output obtained moment by moment during a running test can be represented as a number vector in the bridge output space by a linear combination of the lateral pressure sensitivity and wheel load crossover sensitivity vectors, as shown in Figure 7(b) (bridge output vector).

[0048] The current approach to the weighting function (pseudo-inverse matrix) in the new continuous method can be rephrased as projecting the bridge output vector in the direction of the lateral pressure sensitivity vector and dividing the magnitude of its components by the magnitude of the lateral pressure sensitivity, as shown in Figure 7(b). However, with this method, as shown in Figure 7(c), the effect of the projected component of the wheel load crossing sensitivity appears in the direction of the lateral pressure sensitivity, so the error due to the effect of wheel load is superimposed on the lateral pressure.

[0049] Figure 8(a) shows the orthogonal complementary space orthogonal to the wheel load cross-sensitivity vector in the bridge output space shown in Figure 7(a), and the cross-sensitivity orthogonal weighting function projected onto this orthogonal complementary space to remove the effect of wheel load. Figure 8(b) shows the state in which the cross-sensitivity orthogonal weighting function in (a) cannot be applied.

[0050] As shown in Figure 7(c), errors due to the effect of wheel load are superimposed on the lateral pressure. In contrast, the cross-sensitivity orthogonal weighting function, as shown in Figure 8(a), does not project the bridge output vector in the direction of the lateral pressure sensitivity, but rather projects it onto the orthogonal complement of the subspace spanned by the wheel load cross-sensitivity (more generally, cross-sensitivity) vector. In other words, by projecting the bridge output vector and the lateral pressure sensitivity vector in a direction where the projected component of the wheel load cross-sensitivity is zero, it becomes possible to calculate the lateral pressure without being affected by the wheel load.

[0051] Furthermore, except for the region where the effects of nonlinearity appear at the flange contact area, the "direction" of the wheel load crossing sensitivity vector can be defined to be constant regardless of the left and right contact positions. This has the advantage that lateral pressure can be calculated from the PQ wheelset characteristics and bridge output vector obtained in the verification test, without explicitly knowing the wheel load or left and right contact positions.

[0052] Furthermore, this concept can be easily extended to multiple dimensions. In the case of three dimensions or more, one can consider the projection of the subspace spanned by the wheel load crossing sensitivity and the front-to-rear tangential force crossing sensitivity onto the orthogonal complement space. Note that when the contact position in the circumferential direction changes, the direction of the lateral pressure sensitivity and wheel load crossing sensitivity vectors also generally changes, so measurement of the rotation angle using a rotary encoder or the like becomes necessary.

[0053] Here, Figure 8(b) shows a case where the cross-sensitivity orthogonal weighting function cannot be applied. When the directions of the lateral pressure sensitivity vector and the wheel load cross-sensitivity vector coincide (i.e., these vectors do not form a basis in the bridge output space), the projection component of the bridge output vector onto the orthogonal complement of the wheel load cross-sensitivity becomes zero, and the lateral pressure cannot be calculated. A typical example is the axisymmetric bridge circuit of the current wheel bending method, which has characteristics similar to Figure 8(b), and the cross-sensitivity orthogonal weighting function cannot be applied.

[0054] Furthermore, depending on the combination of bridge circuits, a situation like that shown in Figure 8(b) may occur at certain circumferential contact points, and in the following, such circumferential contact points will be referred to as "singular points."

[0055] The above explains the concept of the cross-sensitivity orthogonal weighting function for the first asymmetric bridge circuit Q11 and the second asymmetric bridge circuit Q12. To cancel out the above singularity, we can use a symmetric bridge circuit Q13, which has a different cross-sensitivity ratio at the singularity than the two systems mentioned above (i.e., the first asymmetric bridge circuit Q11 and the second asymmetric bridge circuit Q12), to find the weighting function (details will be described later).

[0056] [3. Calculation example of sensitivity, crossover sensitivity characteristics, and weighting function of the bridge circuit Q1 for lateral pressure measurement in the first configuration example] Next, Figures 9 to 11 show the sensitivity and cross-sensitivity characteristics of the bridge circuit Q1 for lateral pressure measurement in the first configuration example, as analyzed by the finite element method. Figure 9 shows the relationship between the circumferential loading position and the lateral pressure sensitivity when analyzed by the finite element method using bridge circuits Q11 to Q13. Figure 10 shows the relationship between the circumferential loading position and the wheel load cross-sensitivity at the loading position y in the left and right directions (sleeper direction) when analyzed by the finite element method using bridge circuits Q11 to Q13, where (a) shows the case where the loading position y is at +20 mm (flange side), (b) shows the case where the loading position y is at 0 mm (center of the tread), and (c) shows the case where the loading position y is at -20 mm (opposite flange side). Figure 11 shows the relationship between the circumferential loading position and the front-to-back tangential force crossing sensitivity at the respective left-to-right (sleeper direction) loading positions y when analyzed using the finite element method with bridge circuits Q11 to Q13. (a) shows the case where the loading position y is at +20 mm (flange side), (b) shows the case where the loading position y is at 0 mm (center of the tread), and (c) shows the case where the loading position y is at -20 mm (opposite flange side).

[0057] Furthermore, the weighting functions F11 to F14 of the bridge circuit Q1 for lateral pressure measurement according to the first configuration example are shown in Figures 12 and 13, respectively. Figure 12 is a diagram showing the relationship between the circumferential loading position and the weight when analyzed by the finite element method using the first asymmetric bridge circuit Q11 and the second asymmetric bridge circuit Q12, where (a) shows the weighting function F11 and (b) shows the weighting function F12. Figure 13 is a diagram showing the relationship between the circumferential loading position and the weight when analyzed by the finite element method using the first asymmetric bridge circuit Q11 and the second asymmetric bridge circuit Q12, where (a) shows the weighting function F13 and (b) shows the weighting function F14.

[0058] The weighting functions F11 to F14 mentioned above are as follows: (1) Weighting function F11: A weighting function generated using the same approach as the new continuity method (pseudoinverse matrix of the transverse pressure sensitivity vector) for only two systems of axis-asymmetric bridge circuits, the first asymmetric bridge circuit Q11 and the second asymmetric bridge circuit Q12 (see Figure 12(a)). (2) Weighting function F12: A weighting function generated using an inverse element orthogonal to the ring load crossing sensitivity for only the two systems of the axis-asymmetric bridge circuit described above (see Figure 12(b)). (3) Weighting function F13: A weighting function generated for all three bridge circuits Q11 to Q13 using inverse elements orthogonal to the ring weight crossing sensitivity (see Figure 13(a)). (4) Weighting function F14: A weighting function generated for all three bridge circuits Q11 to Q13 using inverse elements orthogonal to the wheel load crossing sensitivity and the front-to-rear tangential force crossing sensitivity (see Figure 13(b)).

[0059] The weighting function F11 shown in Figure 12(a) above uses the same approach as the current new continuous method, so it is possible to construct a weighting function with sufficient sensitivity over the entire wheel rotation using only two systems. On the other hand, it is not possible to eliminate the effect of apparent lateral pressure.

[0060] To eliminate this, the weighting function F12 shown in Figure 12(b) is obtained by applying an inverse element orthogonal to the wheel load cross sensitivity to the two axial asymmetric bridge circuits. Although the weighting function eliminates the effect of wheel load at most positions in the wheel circumference direction, two singularities occur per wheel rotation, making the value of the weighting function indeterminate. This is because, with only two bridge circuits (the first asymmetric bridge circuit Q11 and the second asymmetric bridge circuit Q12 in this embodiment), there are two positions where the directions of the vectors obtained by aligning the wheel load cross sensitivity and lateral pressure sensitivity of each circuit coincide (i.e., the cross sensitivity ratio of the two bridge circuits is the same).

[0061] To eliminate this singularity, it is sufficient to add at least one bridge circuit with two different crossover sensitivity ratios at the singularity. In the first configuration example, the weighting function F13 shown in Figure 13(a) is the weighting function when an axisymmetric symmetric bridge circuit Q13 is added as a bridge circuit to eliminate the singularity, utilizing the measurement holes 47 (measurement holes 47-3, 47-7) at 90 degrees and 270 degrees.

[0062] As described above, by adding one axisymmetric symmetric bridge circuit Q13, the singularities that occurred around π / 2 ≈ 1.57 rad and 3π / 2 ≈ 4.71 rad disappear. Furthermore, if there are three bridge circuits, such as bridge circuits Q11 to Q13, it is possible to construct a weighting function F14 that is orthogonal to both the wheel load crossing sensitivity and the front-to-rear tangential force crossing sensitivity, as shown in Figure 13(b).

[0063] [4. Regarding the bridge circuit Q2 for lateral pressure measurement in the second configuration example] Next, we will describe a second example of a bridge circuit for measuring lateral pressure, Q2, which is different from the bridge circuit Q1 described above.

[0064] Figure 14 shows the configuration of the wheel used in the lateral pressure measuring device 10, and the arrangement of the strain gauges 60 that constitute the bridge circuit Q2 for lateral pressure measurement according to the second configuration example. (a) is a view of the wheel 40 from the outside in the axle axis direction and the width direction, and (b) and (b) are cross-sectional views taken along the arrow 1-1 and 2-2 of (a), respectively. In Figure 14, the dashed lines indicate the strain gauges 60 corresponding to the bridge circuit Q21, the second asymmetric bridge circuit Q22, and the symmetric bridge circuit Q23 of the bridge circuit Q2 for lateral pressure measurement according to the second configuration example.

[0065] In the first configuration example, the uniaxial strain gauges are strain gauges 62A, 62B, 64A, 64B, 66A, 66B, 68A, and 68B from the strain gauge 60. However, in the second configuration example, the uniaxial strain gauges are 62A, 62B, 66A, and 66B. In other words, in the first configuration example, the uniaxial strain gauges strain gauges 64A, 64B, 68A, and 68B are replaced in the second configuration example by the triaxial strain gauges strain gauges 64A-1, 2, 3, 64B-1, 2, 3, 68A-1, 2, 3, and 68B-1, 2, 3.

[0066] In the second configuration example, the strain gauges 60 other than those mentioned above are triaxial strain gauges, as in the first configuration example.

[0067] As shown in Figure 14, the bridge circuit Q21 is composed of strain gauges 61A and 61B located in measurement hole 47-1 and strain gauges 63A and 63B located in measurement hole 47-3, which is 90 degrees clockwise from measurement hole 47-1. The configuration of the bridge circuit Q21 is as shown in Figure 15.

[0068] Figure 15 shows the configuration of the first asymmetric bridge circuit Q21, which is part of the bridge circuit Q2 for measuring lateral pressure according to the second configuration example. As shown in Figure 15, the first asymmetric bridge circuit Q21 is constructed by sequentially connecting strain gauges 61A-1, 63A-1, 61A-3, 63A-3, 63B-1, 61B-1, 63B-3, and 61B-3 in a ring. The output of this first asymmetric bridge circuit Q21 is the voltage between strain gauges 63A-1 and 61A-3 and between strain gauges 61B-1 and 63B-3.

[0069] Figure 16 shows the configuration of the second asymmetric bridge circuit Q22, which is part of the bridge circuit Q2 for measuring lateral pressure according to the second configuration example. As shown in Figure 16, the second asymmetric bridge circuit Q22 is constructed by sequentially connecting strain gauges 65A-1, 67A-1, 65A-3, 67A-3, 67B-1, 65B-1, 67B-3, and 65B-3 in a ring. The output of this second asymmetric bridge circuit Q22 is the voltage between strain gauges 67A-1 and 65A-3 and between strain gauges 65B-1 and 65B-3.

[0070] Figure 17 shows the configuration of the symmetric bridge circuit Q23, which is part of the bridge circuit Q2 for measuring lateral pressure according to the second configuration example. In the second configuration example, as in the first configuration example, the symmetric bridge circuit Q23 uses a triaxial strain gauge instead of a uniaxial strain gauge. However, the symmetric bridge circuit Q23 may also use a uniaxial strain gauge instead of a triaxial strain gauge.

[0071] As shown in Figure 17, the symmetric bridge circuit Q23 is constructed by sequentially connecting strain gauges 64A-1, 64B-1, 68A-1, 68B-1, 68B-3, 68A-3, 64B-3, and 64A-3 in a ring. The output of this symmetric bridge circuit Q23 is the voltage between strain gauges 6B-1 and 68A-1, and between strain gauges 68A-3 and 64A-3.

[0072] Furthermore, the strain gauges 60 located in measurement holes 47-2 and 47-6 are single-axis strain gauges, enabling the measurement of wheel load P.

[0073] [5. Significance of using the first asymmetric bridge circuit Q21, the second asymmetric bridge circuit Q22, and the symmetric bridge circuit Q23]

[0074] As already explained, the bridge circuit Q1 for measuring lateral pressure in the first configuration example is originally intended to use four axially asymmetric bridge circuits. Therefore, at a point 90 degrees circumferentially from the position where the lateral pressure sensitivity of the first asymmetric bridge circuit Q11 is maximum, the lateral pressure sensitivity becomes low (see Figure 9). At the same time, this position becomes a singularity of the orthogonal weighting function (see Figure 12(b)).

[0075] At this position, the lateral pressure sensitivity of the symmetric bridge circuit Q13 is at its maximum (see Figure 9). However, in Figures 13(a) and 13(b), which take into account the orthogonality with the crossover sensitivity, the weight of the symmetric bridge circuit Q13 at the singularity of π / 2 rad becomes almost zero, and the lateral pressure is effectively determined only by the signals of the first asymmetric bridge circuit Q11 and the second asymmetric bridge circuit Q12.

[0076] Therefore, the bridge circuit Q2 for lateral pressure measurement, shown in Figures 14 to 17, is a configuration aimed at improving the sensitivity characteristics at this singularity. In this bridge circuit Q2 for lateral pressure measurement, the combination of strain gauges 60 placed in measurement holes 47-1 and 47-3, and measurement holes 47-5 and 47-7, respectively, constitutes the first asymmetric bridge circuit Q21 and the second asymmetric bridge circuit Q22, aiming to expand the so-called "measurement range."

[0077] Simultaneously, a symmetric bridge circuit Q23, which is axially symmetric, is constructed using strain gauges 60 positioned at measurement holes 47-4 and 47-8 to eliminate singularities.

[0078] [6. Calculation example of sensitivity, crossover sensitivity characteristics, and weighting function of the bridge circuit Q2 for lateral pressure measurement in the second configuration example] Next, Figures 18 to 20 show the sensitivity and cross-sensitivity characteristics of the bridge circuit Q2 for lateral pressure measurement in the second configuration example, as analyzed by the finite element method. Figure 18 shows the relationship between the circumferential loading position and the lateral pressure sensitivity when analyzed by the finite element method using bridge circuits Q21 to Q23. Figure 19 shows the relationship between the circumferential loading position and the wheel load cross-sensitivity at the loading position y in the left and right directions (sleeper direction) when analyzed by the finite element method using bridge circuits Q21 to Q23, where (a) shows the case where the loading position y is at +20 mm (flange side), (b) shows the case where the loading position y is at 0 mm (center of the tread), and (c) shows the case where the loading position y is at -20 mm (opposite flange side). Figure 20 shows the relationship between the circumferential loading position and the front-to-back tangential force crossing sensitivity at the respective left-to-right (sleeper direction) loading positions y, when analyzed using the finite element method with bridge circuits Q21 to Q23. (a) shows the case where the loading position y is at +20 mm (flange side), (b) shows the case where the loading position y is at 0 mm (center of the tread), and (c) shows the case where the loading position y is at -20 mm (opposite flange side).

[0079] Furthermore, the weighting functions F21 to F24 of the bridge circuit Q2 for lateral pressure measurement in the second configuration example are shown in Figures 21 and 22, respectively. Figure 21 is a diagram showing the relationship between the circumferential loading position and the weight when analyzed by the finite element method using the first asymmetric bridge circuit Q21 and the second asymmetric bridge circuit Q22, where (a) shows the weighting function F21 and (b) shows the weighting function F22. Figure 22 is a diagram showing the relationship between the circumferential loading position and the weight when analyzed by the finite element method using the first asymmetric bridge circuit Q21 and the second asymmetric bridge circuit Q22, where (a) shows the weighting function F23 and (b) shows the weighting function F24.

[0080] The weighting functions F12 to F24 mentioned above are as follows: (1) Weighting function F21: A weighting function generated using the same approach as the new continuous method (pseudoinverse matrix of the transverse pressure sensitivity vector) for only two systems of axis-asymmetric bridge circuits, the first asymmetric bridge circuit Q21 and the second asymmetric bridge circuit Q22 (see Figure 21(a)). (2) Weighting function F22: A weighting function generated using an inverse element orthogonal to the ring load crossing sensitivity for only the two systems of the above axis-asymmetric bridge circuit (see Figure 21(b)). (3) Weighting function F23: A weighting function generated for all three bridge circuits Q21 to Q23 using inverse elements orthogonal to the ring weight crossing sensitivity (see Figure 22(a)). (4) Weighting function F24: A weighting function generated for all three bridge circuits Q21 to Q23 using inverse elements orthogonal to the wheel load crossing sensitivity and the front-to-rear tangential force crossing sensitivity (see Figure 22(b)).

[0081] The basic properties of the weighting functions F21 to F24 shown in Figures 21 and 22 above are the same as those of the weighting functions F11 to F14 in the first configuration example. However, they have the advantage that the weight of the symmetric bridge circuit Q23 is not zero at the singularity location, and the difference between the maximum and minimum values ​​of the weighting functions F21 to F24 is small. From the viewpoint of measurement sensitivity, these properties are more favorable than those of the first configuration example.

[0082] On the other hand, the number of triaxial strain gauges used increases compared to the first configuration example, resulting in the disadvantage of slightly more complicated wiring. As mentioned above, the bridge circuit Q2 for lateral pressure measurement in this second configuration example was initially analyzed with the intention of expanding the measurement range of the asymmetrical bridge circuit, but this effect was not significantly observed in practice.

[0083] [7. Quantitative evaluation of the performance of the bridge circuit Q1 for lateral pressure measurement in the first configuration example and the bridge circuit Q2 for lateral pressure measurement in the second configuration example] Next, we will describe the quantitative evaluation of the performance of the bridge circuit Q1 for lateral pressure measurement in the first configuration example and the bridge circuit Q2 for lateral pressure measurement in the second configuration example. Here, in order to quantitatively evaluate the performance of the bridge circuit Q1 for lateral pressure measurement in the first configuration example and the bridge circuit Q2 for lateral pressure measurement in the second configuration example, we evaluated the maximum value error, minimum value error, and average value error of the continuous lateral pressure over one wheel rotation. The evaluation results are shown in Tables 1 to 4. Note that in the evaluation results shown below, the weighting function F12, which produces singularities, has been excluded from the evaluation.

[0084] First, Table 1 shows the evaluation results for the maximum error, minimum error, and average error under the conditions of wheel load P=40kN, lateral pressure Q=30kN, longitudinal tangential force T=0kN, loading position y=30mm, and Δφ=0rad. Note that Δφ is the wheel rotation angle measurement error.

[0085] [Table 1]

[0086] Next, Table 2 shows the evaluation results for the maximum error, minimum error, and average error under the conditions of wheel load P=40kN, lateral pressure Q=30kN, longitudinal tangential force T=10kN, loading position y=30mm, and Δφ=0rad.

[0087] [Table 2]

[0088] Next, Table 3 shows the evaluation results for the maximum error, minimum error, and average error under the conditions of wheel load P=40kN, lateral pressure Q=30kN, longitudinal tangential force T=0kN, loading position y=30mm, and Δφ=0.05rad.

[0089] [Table 3]

[0090] Next, Table 4 shows the evaluation results for the maximum error, minimum error, and average error under the conditions of wheel load P=40kN, lateral pressure Q=30kN, longitudinal tangential force T=10kN, loading position y=30mm, and Δφ=0.05rad.

[0091] [Table 4]

[0092] As shown in Tables 1 to 4 above, the maximum error, minimum error, and average error evaluation results obtained using weighting functions F13, F23 and F14, F24 show errors of roughly the same order of magnitude under all conditions. However, the absolute values ​​of the maximum and minimum errors under conditions where tangent forces T act (Tables 2 and 4) tend to be smaller when processed using weighting functions F14 and F24.

[0093] Therefore, when comparing the processing results using the weighting function F14 of the bridge circuit Q1 for lateral pressure measurement in the first configuration example and the weighting function F24 of the bridge circuit Q2 for lateral pressure measurement in the second configuration example, the average error is roughly the same, although it varies slightly depending on the conditions, or the bridge circuit Q2 for lateral pressure measurement in the second configuration example tends to have a slightly larger error.

[0094] On the other hand, the maximum and minimum error tend to be smaller in the bridge circuit Q2 for lateral pressure measurement according to the second configuration example, and in particular, under Table 4, which is assumed to be the dry conditions when passing through a curve, the bridge circuit Q2 for lateral pressure measurement according to the second configuration example is advantageous.

[0095] Even under the conditions shown in Table 1, which have the fewest error factors, some error still occurs. This is because the offset component of the crossover sensitivity is not taken into account. In the case of three systems, only two vectors can be considered as crossover sensitivity, so it is not possible to incorporate a function to compensate for this error into the weighting function.

[0096] [8. Addendum] The contents described in the above-mentioned embodiment can be understood as follows, for example, and can produce the following effects. [1] That is, A lateral pressure measuring device 10 for measuring the lateral pressure between the wheel 40 of a railway vehicle and the rail R, Wheel 40 is A rim portion 42 is provided on the outer edge and has a tread surface 43 formed thereon, A hub portion 41 is provided in the center and to which the axle is attached, It has a plate portion 45 provided between the rim portion 42 and the hub portion 41, The lateral pressure measuring device 10 is At least two asymmetrical bridge circuits (first asymmetrical bridge circuits Q11, Q21, second asymmetrical bridge circuits Q12, Q22) are provided with strain gauges 60 mounted in asymmetrical positions on either side of the rotation center of the wheel 40, Symmetrical bridge circuits Q13, Q23 equipped with strain gauges 60 mounted in symmetrical positions with respect to the center of rotation, The system includes at least two asymmetric bridge circuits (first asymmetric bridge circuits Q11, Q21, second asymmetric bridge circuits Q12, Q22) and a calculation unit 120 that performs calculations based on the outputs of symmetric bridge circuits Q13, 23. Equipped with, The calculation unit 120 is, The lateral pressure is calculated based on the inverse of the lateral pressure sensitivity vector orthogonal to the proportionality constant vector of the wheel load crossing sensitivity and / or the longitudinal tangential force in the output sensitivity characteristics of the asymmetric bridge circuits (first asymmetric bridge circuits Q11, Q21, second asymmetric bridge circuits Q12, Q22), which change according to the wheel load P between the wheel 40 and the rail R and the longitudinal tangential force T of the wheel 40, and For outputs from the asymmetric bridge circuits (first asymmetric bridge circuits Q11, Q21, second asymmetric bridge circuits Q12, Q22) that relate to singularities where the directions of the lateral pressure sensitivity vector and the wheel load cross sensitivity vector coincide, calculations are performed to cancel out the singularities based on the outputs from symmetric bridge circuits Q13, Q23, which have a different cross sensitivity ratio than the asymmetric bridge circuits (first asymmetric bridge circuits Q11, Q21, second asymmetric bridge circuits Q12, Q22).

[0097] By adopting this configuration, the influence of wheel load crossing sensitivity in the bridge circuits Q1 and Q2 used for lateral pressure measurement can be reduced by using at least two asymmetric bridge circuits (first asymmetric bridge circuits Q11, Q21, second asymmetric bridge circuits Q12, Q22), enabling accurate calculation of continuous lateral pressure. Furthermore, by using symmetric bridge circuits Q13 and Q23, the influence of singularities in the outputs from the asymmetric bridge circuits (first asymmetric bridge circuits Q11, Q21, second asymmetric bridge circuits Q12, Q22) where the directions of the lateral pressure sensitivity vector and the wheel load crossing sensitivity vector coincide can be canceled out.

[0098] In addition, by using a symmetrical bridge circuit instead of two of the four asymmetrical bridge circuits, as described in Non-Patent Document 6, it is possible to reduce the number of channels.

[0099] [2] In addition, in the above embodiment, in item [1] above, At least two asymmetric bridge circuits (first asymmetric bridge circuit Q11, Q21, second asymmetric bridge circuit Q12, Q22) are two sets of asymmetric bridge circuits whose sensitivity characteristics have a phase difference of 180 degrees from each other. It is preferable that the symmetric bridge circuits Q13 and Q23 are positioned such that their sensitivity characteristics are 90 degrees apart in phase from both of the two sets of asymmetric bridge circuits (first asymmetric bridge circuits Q11 and Q21, and second asymmetric bridge circuits Q12 and Q22).

[0100] In this configuration, the outputs from the two sets of asymmetric bridge circuits (first asymmetric bridge circuit Q11, Q21, second asymmetric bridge circuit Q12, Q22) provide good lateral pressure sensitivity, enabling accurate measurement of lateral pressure.

[0101] [3] In addition, the above embodiments include, in addition to the contents described in either [1] or [2] above, or a combination thereof, Each of the at least two asymmetric bridge circuits (first asymmetric bridge circuits Q11, Q21, second asymmetric bridge circuits Q12, Q22) is configured such that strain gauges 60 attached to measurement holes 47 of plate sections 45, which are at different angular positions of 90 degrees, are coupled to each other. It is preferable that the symmetrical bridge circuits 13 and 23 are positioned in a phase difference from each of the asymmetrical bridge circuits (first asymmetrical bridge circuits Q11 and Q21, and second asymmetrical bridge circuits Q12 and Q22).

[0102] This configuration makes it possible to reduce the impact of errors in measuring the rotation angle of the wheel 40.

[0103] [4] In addition, in this embodiment, the descriptions in any of [1] to [3] above, or a combination thereof, Strain gauges 60 (strain gauges 61A-1,2,3, 61B-1,2,3, 63A-1,2,3, 63B-1,2,3, 65A-1,2,3, 65B-1,2,3, 67A-1,2,3, 67B-1,2,3, and strain gauges 64A-1,2,3, 64B-1,2,3 in Figure 14) are triaxial strain gauges, It is preferable that single-axis strain gauges for measuring wheel load (strain gauges 62A, 62B, 64A, 64B, 66A, 66B, 68A, 68B in Figure 3 and strain gauges 62A, 62B, 66A, 66B in Figure 14) are mounted at an angular position different from that of the aforementioned strain gauge 60.

[0104] This configuration allows for accurate measurement of lateral pressure using a three-axis strain gauge, while also enabling accurate measurement of wheel load using a single-axis strain gauge.

[0105] [5] In addition, in the lateral pressure measurement method for measuring the lateral pressure between the wheel 40 of the railway vehicle and the rail R of this embodiment, Wheel 40 is A rim portion 42 is provided on the outer edge and has a tread surface 43 formed thereon, A hub portion 41 is provided in the center and to which the axle is attached, It has a plate portion 45 provided between the rim portion 42 and the hub portion 41, The lateral pressure measuring device 10 that performs the lateral pressure measurement method is At least two asymmetrical bridge circuits (first asymmetrical bridge circuits Q11, Q21, second asymmetrical bridge circuits Q12, Q22) are provided with strain gauges 60 mounted in asymmetrical positions on either side of the rotation center of the wheel 40, Symmetrical bridge circuits Q13, Q23 equipped with strain gauges 60 mounted in symmetrical positions with respect to the center of rotation, Equipped with, The calculation process is performed based on the outputs of at least two asymmetric bridge circuits (first asymmetric bridge circuits Q11, Q21, second asymmetric bridge circuits Q12, Q22) and symmetric bridge circuits Q13, 23. In this calculation process, The lateral pressure is calculated based on the inverse of the lateral pressure sensitivity vector orthogonal to the proportionality constant vector of the wheel load crossing sensitivity and / or the longitudinal tangential force in the output sensitivity characteristics of the asymmetric bridge circuits (first asymmetric bridge circuits Q11, Q21, second asymmetric bridge circuits Q12, Q22), which change according to the wheel load P between the wheel 40 and the rail R and the longitudinal tangential force T of the wheel 40, and For outputs from the asymmetric bridge circuits (first asymmetric bridge circuits Q11, Q21, second asymmetric bridge circuits Q12, Q22) that relate to singularities where the directions of the lateral pressure sensitivity vector and the wheel load cross sensitivity vector coincide, calculations are performed to cancel out the singularities based on the outputs from symmetric bridge circuits Q13, Q23, which have a different cross sensitivity ratio than the asymmetric bridge circuits (first asymmetric bridge circuits Q11, Q21, second asymmetric bridge circuits Q12, Q22).

[0106] By using this lateral pressure measurement method, and employing at least two asymmetric bridge circuits (first asymmetric bridge circuits Q11, Q21, second asymmetric bridge circuits Q12, Q22), the influence of wheel load crossing sensitivity in the lateral pressure measurement bridge circuits Q1 and Q2 can be reduced, enabling accurate calculation of continuous lateral pressure. Furthermore, by using symmetric bridge circuits Q13 and Q23, the influence of singularities in the outputs from the asymmetric bridge circuits (first asymmetric bridge circuits Q11, Q21, second asymmetric bridge circuits Q12, Q22) where the directions of the lateral pressure sensitivity vector and the wheel load crossing sensitivity vector coincide can be canceled out.

[0107] In addition, by using a symmetrical bridge circuit instead of two of the four asymmetrical bridge circuits, as described in Non-Patent Document 6, it is possible to reduce the number of channels.

[0108] <Variation> The embodiments of the present invention have been described above, but the present invention can be modified in various ways beyond these. These modifications will be described below.

[0109] In the above embodiment, there are eight measuring holes 47, and each of these measuring holes 47 is fitted with either a triaxial or monoaxial strain gauge 60. However, the number of measuring holes 47 may be an even number, such as four or more, and triaxial or monoaxial strain gauges 60 may be fitted into them as appropriate. [Explanation of Symbols]

[0110] 10... Lateral pressure measuring device, 20... PQ wheelset, 30... Wheelset, 40... Wheel, 41... Hub section, 41a... Hub hole, 42... Rim section, 43... Tread, 44... Flange, 45... Plate section, 47, 47-1~47-8... Measuring holes, 50... Axle, 60, 61A-1, 2, 3, 61B-1, 2, 3, 62A, 62B, 63A-1, 2, 3, 63B--1,2,3,64A,64B,64A-1,2,3,64B-1,2,3,65A-1,2,3,65B-1,2,3,66A,66B,67A-1,2,3,67B-1,2,3,68A,68B…strain gauges, 100…slip ring device, 110…strain signal processing unit, 120…calculation unit

Claims

1. A lateral pressure measuring device for measuring the lateral pressure between the wheels and rails of a railway vehicle, The aforementioned wheel is A rim portion is provided on the outer edge and has a tread surface formed therein, A hub section located in the center to which the axle is attached, It has a plate portion provided between the rim portion and the hub portion, The aforementioned lateral pressure measuring device is At least two asymmetrical bridge circuits equipped with strain gauges mounted at asymmetrical positions on either side of the wheel's center of rotation, A symmetrical bridge circuit comprising the strain gauges mounted at positions symmetrical to each other with respect to the rotation center, The system comprises at least two asymmetric bridge circuits and a calculation unit that performs calculations based on the outputs of the symmetric bridge circuit. Equipped with, The aforementioned arithmetic unit, The lateral pressure is calculated based on the inverse of the lateral pressure sensitivity vector orthogonal to the proportionality constant vector of the wheel load crossing sensitivity and / or the lateral tangential force in the output sensitivity characteristics of the asymmetric bridge circuit, which changes according to the wheel load between the wheel and the rail and the tangential force of the wheel, For the output from the asymmetric bridge circuit relating to a singularity where the directions of the lateral pressure sensitivity vector and the wheel load cross sensitivity vector coincide, a calculation is performed to cancel out the singularity based on the output from the symmetric bridge circuit, which has a different cross sensitivity ratio than the asymmetric bridge circuit. A lateral pressure measuring device characterized by the following features.

2. A lateral pressure measuring device according to claim 1, At least two of the aforementioned asymmetric bridge circuits are two sets of the aforementioned asymmetric bridge circuits whose sensitivity characteristics have a phase difference of 180 degrees from each other. The symmetric bridge circuit is positioned such that its sensitivity characteristics are 90 degrees out of phase with respect to both of the two sets of asymmetric bridge circuits. A lateral pressure measuring device characterized by the following features.

3. A lateral pressure measuring device according to claim 1, Each of the at least two asymmetric bridge circuits is configured such that the strain gauges attached to the measuring holes in the plate portion, which are at different angular positions of 90 degrees, are coupled to each other. The symmetrical bridge circuit is positioned in a location where its phase is different from that of any of the asymmetrical bridge circuits. A lateral pressure measuring device characterized by the following features.

4. A lateral pressure measuring device according to claim 1, The strain gauge is a three-axis strain gauge, A single-axis strain gauge for measuring wheel load is mounted at a different angular position than the aforementioned strain gauge. A lateral pressure measuring device characterized by the following features.

5. A method for measuring lateral pressure between the wheels and rails of a railway vehicle, The aforementioned wheel is A rim portion is provided on the outer edge and has a tread surface formed therein, A hub section located in the center to which the axle is attached, It has a plate portion provided between the rim portion and the hub portion, A lateral pressure measuring device that implements the lateral pressure measuring method described above is: At least two asymmetrical bridge circuits equipped with strain gauges mounted at asymmetrical positions on either side of the wheel's center of rotation, A symmetrical bridge circuit comprising the strain gauges mounted at positions symmetrical to each other with respect to the rotation center, Equipped with, Based on the outputs of the at least two asymmetric bridge circuits and the symmetric bridge circuit, calculation processing is performed. In the aforementioned calculation process, The lateral pressure is calculated based on the inverse of the lateral pressure sensitivity vector orthogonal to the proportionality constant vector of the wheel load crossing sensitivity and / or the lateral tangential force in the output sensitivity characteristics of the asymmetric bridge circuit, which changes according to the wheel load between the wheel and the rail and the tangential force of the wheel, For the output from the asymmetric bridge circuit relating to a singularity where the directions of the lateral pressure sensitivity vector and the wheel load cross sensitivity vector coincide, a calculation is performed to cancel out the singularity based on the output from the symmetric bridge circuit, which has a different cross sensitivity ratio than the asymmetric bridge circuit. A method for measuring lateral pressure characterized by the following features.

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