An indirect test method for the wheel-rail forces of the three-part bogie of a railway freight car

Abstract

The invention discloses an indirect test method for wheel-rail force of a three-component bogie of a railway freight car, which belongs to the field of railway testing technology. The method comprises the following steps: modifying an axle box rubber pad of an original three-component bogie of a railway freight car to obtain a modified axle box rubber pad; patching the modified axle box rubber pad and assembling a bridge to obtain an axle box rubber pad carrying a Wheatstone full bridge group; obtaining proportional coefficients between lateral, longitudinal and vertical loads and output voltage signals of the Wheatstone full bridge group; establishing a force model of the axle box rubber pad carrying the Wheatstone full bridge group; establishing a mechanical model of wheel-rail vertical force and wheel axle lateral force of the three-component bogie of a railway freight car; assembling the axle box rubber pad carrying the Wheatstone full bridge group to the left and right sides of a wheel pair of a three-component bogie of a railway freight car to test the wheel-rail force; the invention solves the problems that the traditional force measuring wheelset technology is too costly when large-scale railway freight trains are equipped to monitor the wheel-rail force and the traditional force measuring rail technology cannot realize continuous measurement.

Description

Technical Field

[0001] The invention belongs to the technical field of railway testing, and in particular relates to an indirect testing method for wheel-rail acting forces of a bogie of three major parts of a railway freight car. Background Art

[0002] Railway freight cars are heavy-loaded, have long train formations, and have many long downhill slopes in their operating ranges. The inertia of the vehicles during braking is large, the braking time is long, and the braking force of the front and rear vehicles is not uniform, which can easily cause abnormal interactions between the front and rear vehicles, directly leading to the deterioration of the wheel-rail contact relationship and easily inducing train derailment accidents. In order to ensure the safety of railway freight car operation and improve the reliability of railway freight, it is necessary to simultaneously monitor the braking force, coupler force, and wheel-rail force during railway freight car operation, study the relationship between the three, and optimize the safe operation and status inspection of railway freight cars.

[0003] There are two main existing methods for testing wheel-rail forces, namely the wheelset test method and the rail test method. The wheelset test method requires the production of a special force-measuring wheelset, which requires drilling, patching, bridge assembly and calibration on the wheelset, and replacing the completed force-measuring wheelset on the bogie to monitor the wheel-rail force in real time. Railway freight cars are composed of hundreds of cars. In order to fully reflect the dynamic characteristics of the entire train, it is necessary to monitor the wheel-rail forces of multiple axle positions of the train at the same time. However, the production process of the force-measuring wheelset is complicated and the manufacturing cost is high. It is not suitable for large-scale equipment, and the force-measuring wheelset technology cannot correctly reflect the wheel-rail force under braking conditions. Therefore, the force-measuring wheelset is not suitable for equipment on railway freight cars; and the rail test method is to stick sensors on the rails and collect signals on the ground. When the train passes, the wheel-rail force at that moment is obtained. This test method has spatial limitations and cannot reflect the wheel-rail force during the entire train operation process. Therefore, it is necessary to find a wheel-rail force test method that can be tested continuously, has low cost, high accuracy, and can be equipped on a large scale. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the present invention provides an indirect testing method for the wheel-rail force of the three major components of a railway freight car bogie, which solves the problems of high cost of traditional force measuring wheelset technology and inability of traditional force measuring rail technology to achieve continuous measurement when monitoring wheel-rail force on large-scale railway freight trains.

[0005] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is:

[0006] The present invention provides an indirect test method for the wheel-rail force of a railway freight car bogie, comprising the following steps:

[0007] S1. Reconstructing the rubber pads of the axle box of the original three major parts of the railway freight car bogie to obtain the reconstructed axle box rubber pads;

[0008] S2, patch the modified axle box rubber pad and assemble the bridge to obtain the axle box rubber pad carrying the Wheatstone full bridge group;

[0009] S3, loading the axle box rubber pad carrying the Wheatstone full-bridge group in the transverse, longitudinal and vertical directions, and obtaining the proportional coefficients between the transverse, longitudinal and vertical loads and the output voltage signal of the Wheatstone full-bridge group respectively;

[0010] S4. Based on the proportionality coefficients between the lateral, longitudinal and vertical loads and the output voltage signal of the Wheatstone full-bridge group, a force model of the axle box rubber pad carrying the Wheatstone full-bridge group is established;

[0011] S5. Based on the force model of the axle box rubber pad with the full Wheatstone bridge group, the mechanical model of the wheel-rail vertical force and the wheel-axle lateral force of the three major parts of the railway freight car bogie is established;

[0012] S6. Assemble the axle box rubber pads carrying the Wheatstone full bridge group to the left and right sides of the three-part bogie wheel set of the railway freight car, and test the wheel-rail force based on the mechanical model of the wheel-rail vertical force and the wheel-axle lateral force of the three-part bogie of the railway freight car, and complete the indirect test of the wheel-rail force of the three-part bogie of the railway.

[0013] The beneficial effects of the present invention are as follows: the indirect test method for the wheel-rail force of the three major parts of the bogie of a railway freight car provided by the present invention analyzes the transmission paths of the wheel-rail force of the three major parts of the bogie of the railway freight car from bottom to top, which are: wheel-axle-load saddle-axle box rubber pad-bogie side frame, wherein the axle box rubber pad is fully deformed after being subjected to force, and the test signal is obvious, so it is suitable for testing the wheel-rail force, so the original truck bogie axle box rubber pad is processed and modified, the method for modifying the axle box rubber pad is simple, and the decoupling of the forces in various directions can be achieved by modifying the axle box rubber pad, the test result is accurate, and compared with the mature force measuring wheelset technology, the test relative error can be guaranteed to be within 10%; compared with the traditional force measuring wheelset technology and the force measuring rail technology, the continuous long-term monitoring of the wheel-rail force of the freight car can be achieved, and the test cost is much lower than the traditional force measuring wheelset technology or the force measuring rail technology, and the present method is suitable for large-scale equipment of railway freight trains, and the wheel-rail force of multiple axle positions of the freight train is monitored in real time, so as to realize the online evaluation of the running safety of the train, optimize the operation of the train, and ensure the safe and punctual arrival of the freight train.

[0014] Furthermore, the original railway freight car bogie axle box rubber pad includes an upper steel lining, a middle rubber layer, a lower steel lining, a left upper positioning stopper of the rubber pad, and a right upper positioning stopper of the rubber pad;

[0015] The middle rubber layer is arranged above the lower steel lining plate; the upper steel lining plate is arranged above the middle rubber layer; the upper left positioning stop of the rubber pad and the upper right positioning stop of the rubber pad are relatively arranged above the left and right ends of the upper steel lining plate.

[0016] The beneficial effects of adopting the above further scheme are: under vertical force, since the edge of the lower steel lining of the rubber pad is thinner, this part is fully deformed and the test signal is obvious, which is suitable for vertical force testing. Small lateral force or longitudinal force needs to be tested by the friction between the upper steel lining of the rubber pad and the bogie side frame. The large lateral force or longitudinal force is borne jointly by the sliding friction of the upper steel lining of the rubber pad and the upper positioning stop. By dividing the modified axle box rubber pad structure, it can be effectively used to paste stress sheets and assemble a Wheatstone full bridge.

[0017] Furthermore, the step S1 comprises the following steps:

[0018] S11, symmetrically cutting strip grooves along the edges of the long sides of the lower steel liner of the axle box rubber pad to obtain a first strip groove and a second strip groove symmetrically arranged on the long sides of the lower steel liner;

[0019] S12. A rectangular groove is opened at the central position of the surface of the upper steel liner of the axle box rubber pad to obtain a modified axle box rubber pad.

[0020] The beneficial effect of adopting the above further scheme is: the surface of the lower steel liner and the upper steel liner of the axle box rubber pad is grooved to provide a basis for setting strain gauges.

[0021] Furthermore, the step S2 comprises the following steps:

[0022] S21, respectively affixing the first vertical force test strain gauge V1 and the second vertical force test strain gauge V2 to the first strip groove position of the lower steel lining plate of the modified axle box rubber pad, and respectively affixing the third vertical force test strain gauge V3 and the fourth vertical force test strain gauge V4 to the second strip groove position of the lower steel lining plate of the modified axle box rubber pad, wherein the first vertical force test strain gauge V1 and the second vertical force test strain gauge V2 are respectively arranged in one-to-one correspondence with the third vertical force test strain gauge V3 and the fourth vertical force test strain gauge V4;

[0023] S22, forming a first Wheatstone full bridge based on the first vertical force test strain gauge V1 and the second vertical force test strain gauge V2, and forming a second Wheatstone full bridge based on the third vertical force test strain gauge V3 and the fourth vertical force test strain gauge V4;

[0024] S23, a first transverse friction test strain gauge L1 and a second transverse friction test strain gauge L2 are arranged along one side perpendicular to the horizontal direction of the rectangular groove of the upper steel lining plate of the modified axle box rubber pad, and a third transverse friction test strain gauge L3 and a fourth transverse friction test strain gauge L4 are arranged along the other side perpendicular to the horizontal direction of the rectangular groove of the upper steel lining plate of the modified axle box rubber pad, wherein the first transverse friction test strain gauge L1 and the second transverse friction test strain gauge L2 are arranged in a one-to-one correspondence with the third transverse friction test strain gauge L3 and the fourth transverse friction test strain gauge L4, respectively, the first transverse friction test strain gauge L1 and the second transverse friction test strain gauge L2 are respectively at an angle of 45 degrees to one side of the horizontal direction of the rectangular groove of the upper steel lining plate of the rubber pad, and the third transverse friction test strain gauge L3 and the fourth transverse friction test strain gauge L4 are respectively at an angle of 45 degrees to the other side of the horizontal direction of the rectangular groove of the upper steel lining plate of the rubber pad;

[0025] S24, a first longitudinal friction test strain gauge X1 and a second longitudinal friction test strain gauge X2 are arranged along one side perpendicular to the longitudinal direction of the rectangular groove of the upper steel lining of the modified axle box rubber pad, and a third longitudinal friction test strain gauge X3 and a fourth longitudinal friction test strain gauge X4 are arranged along the other side perpendicular to the longitudinal direction of the rectangular groove of the upper steel lining of the modified axle box rubber pad, wherein the first longitudinal friction test strain gauge X1 and the second longitudinal friction test strain gauge X2 are arranged in one-to-one correspondence with the third longitudinal friction test strain gauge X3 and the fourth longitudinal friction test strain gauge X4, respectively, the first longitudinal friction test strain gauge X1 and the second longitudinal friction test strain gauge X2 are respectively at an angle of 45 degrees to one side of the longitudinal direction of the rectangular groove of the upper steel lining of the rubber pad, and the third longitudinal friction test strain gauge X3 and the fourth longitudinal friction test strain gauge X4 are respectively at an angle of 45 degrees to the other side of the longitudinal direction of the rectangular groove of the upper steel lining of the rubber pad;

[0026] S25, forming a third Wheatstone full bridge based on the first transverse friction test strain gauge L1, the second transverse friction test strain gauge L2, the third transverse friction test strain gauge L3 and the fourth transverse friction test strain gauge L4, and forming a fourth Wheatstone full bridge based on the first longitudinal friction test strain gauge X1, the second longitudinal friction test strain gauge X2, the third longitudinal friction test strain gauge X3 and the fourth longitudinal friction test strain gauge X4;

[0027] S26, respectively set the first positioning block vertical strain gauge D y1 and the first positioning longitudinal strain gauge D x1 , the second positioning vertical strain gauge D y2 and the second positioning block longitudinal strain gauge D x2 At both ends of the positioning block on the left upper side of the modified axle box rubber pad, a third positioning block vertical strain gauge D is set respectively y3And the third positioning block longitudinal strain gauge D x3 , the fourth positioning vertical strain gauge D y4 And the fourth positioning longitudinal strain gauge D x4 At both ends of the positioning stop on the upper right side of the modified axle box rubber pad;

[0028] S27, based on the vertical strain gauge D of the first positioning block y1 , the second positioning vertical strain gauge D y2 , the third positioning vertical strain gauge D y3 And the fourth positioning vertical strain gauge D y4 The fifth Wheatstone full bridge is constructed, and based on the first positioning block longitudinal strain gauge D x1 , the second positioning block longitudinal strain gauge D x2 , the third positioning block longitudinal strain gauge D x3 And the fourth positioning block longitudinal strain gauge D x4 The sixth Wheatstone full bridge is assembled, and the axle box rubber pad carrying the Wheatstone full bridge group is obtained.

[0029] The beneficial effects of adopting the above further scheme are: providing a specific method for obtaining a Wheatstone full bridge group after the modified axle box rubber pad patch and the bridge assembly, the output voltage corresponding to the wheel-rail vertical force through the first Wheatstone full bridge and the second Wheatstone full bridge, the output voltage corresponding to the lateral friction force between the upper steel lining and the bogie side frame through the third Wheatstone full bridge, the longitudinal friction force between the upper steel lining and the bogie side frame through the fourth Wheatstone full bridge, the lateral force of the force between the left and right positioning blocks and the bogie side frame through the fifth Wheatstone full bridge output voltage corresponding to the complete wheel-rail lateral force, and the longitudinal force between the left and right positioning blocks and the bogie side frame through the sixth Wheatstone full bridge output voltage.

[0030] Further, the Wheatstone full bridge group includes a first Wheatstone full bridge, a second Wheatstone full bridge, a third Wheatstone full bridge, a fourth Wheatstone full bridge, a fifth Wheatstone full bridge and a sixth Wheatstone full bridge.

[0031] The beneficial effect of adopting the above further scheme is: the Wheatstone full bridge group consisting of the first Wheatstone full bridge, the second Wheatstone full bridge, the third Wheatstone full bridge, the fourth Wheatstone full bridge, the fifth Wheatstone full bridge and the sixth Wheatstone full bridge is installed on the modified axle box rubber pad, and the voltage signal output by the Wheatstone full bridge group accurately reflects the stress condition of the axle box rubber itself.

[0032] Furthermore, step S3 includes the following steps:

[0033] S31, the axle box rubber pad carrying the Wheatstone full bridge group is transversely loaded, and the transverse load F is obtained respectively. y The output voltage of the third Wheatstone full bridge isyf The proportionality coefficient k yf and the lateral load F y The fifth Wheatstone full-bridge output voltage ε yd The proportionality coefficient k yd ;

[0034] S32, longitudinal load the rubber pad of the axle box carrying the full Wheatstone bridge group, and obtain the longitudinal load F x The fourth Wheatstone full-bridge output voltage ε xf The proportionality coefficient k xf and longitudinal load F x The output voltage of the sixth Wheatstone full bridge ε xd The proportionality coefficient k xd ;

[0035] S33, vertically load the axle box rubber pad carrying the Wheatstone full bridge group, and obtain the vertical load F z The output voltage of the first Wheatstone full bridge is z1 The proportionality coefficient k z1 and vertical load F z The second Wheatstone full-bridge output voltage ε z2 The proportionality coefficient k z2 .

[0036] The beneficial effect of adopting the above further scheme is: the axle box rubber pad carrying the Wheatstone full-bridge group is loaded laterally, longitudinally and vertically, and the proportional coefficients between the transverse, longitudinal and vertical loads and the output voltage signal of the Wheatstone full-bridge group are obtained.

[0037] Furthermore, the expression of the force model of the axle box rubber pad carrying the Wheatstone full bridge group in step S4 is as follows:

[0038]

[0039] The beneficial effect of adopting the above further scheme is: providing a force model of the axle box rubber pad carrying the Wheatstone full bridge group, providing a basis for calculating the mechanical model of the wheel-rail vertical force and the axle lateral force of the three major parts of the railway freight car bogie.

[0040] Furthermore, the expressions of the mechanical models of the wheel-rail vertical force and the wheel-axle lateral force of the three major components of the railway freight car in step S5 are as follows:

[0041] m w ·a z ·l c / 2+F zl ·l c / 2-F zr ·l c / 2+G·l c / 2-Q l ·l c +H·r0=0

[0042] m w ·a z ·l c / 2+F zr ·l c / 2-F zl ·l c / 2+G·l c / 2-Q r ·l c -H·r0=0

[0043] H=F yl +F yr +m w ·a y

[0044] Where H is the lateral force of the wheel axle, F yl and F yr Respectively represent the lateral force on the rubber pad on the left side of the wheelset and the lateral force on the rubber pad on the right side of the wheelset, m w Indicates the wheelset mass, a y represents the lateral acceleration of the wheelset, a z represents the vertical acceleration of the wheelset, l c Indicates the lateral span of the left and right rubber pads of the wheelset, F zl and F zr They represent the vertical force of the rubber pad on the left side of the wheelset and the vertical force of the rubber pad on the right side of the wheelset, G represents the weight of the wheelset, and Q l and Q r They represent the left wheel-rail vertical force and the right wheel-rail vertical force respectively, and r0 represents the wheel radius.

[0045] The beneficial effects of adopting the above further solution are: providing the wheel axle lateral force H and the left wheel rail vertical force Q l and the right wheel-rail vertical force Q r The calculation method is to calculate H to represent the lateral force of the wheel axle and the vertical force Q of the left wheel rail. l The vertical force Q between the right wheel and rail r , and provide a basis for completing the testing of the wheel-rail force test system of the three major railway components, the bogie. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 The present invention is a flowchart of the steps of the indirect testing method of the wheel-rail force of the bogie of the three major components of a railway freight car in an embodiment of the present invention.

[0047] Figure 2 It is a schematic structural diagram of the rubber pad of the bogie axle box of the original railway freight car's three major parts in an embodiment of the present invention.

[0048] Figure 3 Schematic diagram of the modification of the axle box rubber pad in the embodiment of the present invention.

[0049] Figure 4 Schematic diagram of the construction of the first Wheatstone full bridge and the second Wheatstone full bridge for vertical force testing in an embodiment of the present invention.

[0050] Figure 5 Schematic diagram of the construction of the third Wheatstone full bridge for lateral force testing in an embodiment of the present invention.

[0051] Figure 6 Schematic diagram of the construction of the fourth Wheatstone full bridge for longitudinal force testing in an embodiment of the present invention.

[0052] Figure 7 Schematic diagram of the construction of the fifth Wheatstone full bridge for lateral force testing in an embodiment of the present invention.

[0053] Figure 8 Schematic diagram of the sixth Wheatstone full bridge for longitudinal force testing in an embodiment of the present invention.

[0054] Fig. 9 1 is a curve diagram showing the change of the output voltage of the first Wheatstone full bridge as the vertical, lateral and longitudinal loads increase in the embodiment of the present invention.

[0055] Fig.10 1 is a curve diagram showing the change of the output voltage of the second Wheatstone full bridge with the increase of vertical, lateral and longitudinal loads in an embodiment of the present invention.

[0056] Fig.11 1 is a curve diagram showing the change of the output voltage of the third Wheatstone full bridge as the vertical, lateral and longitudinal loads increase in the embodiment of the present invention.

[0057] Fig.12 1 is a curve diagram showing the change of the output voltage of the fourth Wheatstone full-bridge as the vertical, lateral and longitudinal loads increase in the embodiment of the present invention.

[0058] Fig.13 1 is a curve diagram showing the change of the output voltage of the fifth Wheatstone full-bridge with the increase of vertical, lateral and longitudinal loads in the embodiment of the present invention.

[0059] Fig.14 1 is a curve diagram showing the change of the output voltage of the sixth Wheatstone full-bridge as the vertical, lateral and longitudinal loads increase in the embodiment of the present invention.

[0060] Fig.15 It is a comparison diagram of the wheel-rail vertical force directly measured by the traditional mature dynamometric wheelset in the embodiment of the present invention and the wheel-rail vertical force indirectly measured by the dynamometric rubber pad in this solution.

[0061] Fig.16 This is a comparison chart of the axle lateral force obtained by direct testing of a traditional mature dynamometric wheelset in an embodiment of the present invention and the axle lateral force obtained by indirect testing of the dynamometric rubber pad in this solution.

[0062] Among them: 801, upper steel lining; 802, middle rubber layer; 803, lower steel lining; 804, upper left positioning stop of rubber pad; 805, upper right positioning stop of rubber pad. DETAILED DESCRIPTION

[0063] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0064] like Figure 1 As shown, in an embodiment of the present invention, the present invention also provides an indirect test method for the wheel-rail force of the three major parts of a railway freight car bogie, comprising the following steps:

[0065] The steps include:

[0066] S1. Reconstructing the rubber pads of the axle box of the original three major parts of the railway freight car bogie to obtain the reconstructed axle box rubber pads;

[0067] like Figure 2 As shown, the original railway freight car bogie axle box rubber pad includes an upper steel lining plate 801, a middle rubber layer 802, a lower steel lining plate 803, a positioning stopper 804 on the upper left side of the rubber pad, and a positioning stopper 805 on the upper right side of the rubber pad;

[0068] The middle rubber layer 802 is arranged above the lower steel lining plate 803; the upper steel lining plate 801 is arranged above the middle rubber layer 802; the upper left side positioning stop 804 of the rubber pad and the upper right side positioning stop 805 of the rubber pad are arranged above the left and right ends of the upper steel lining plate 801;

[0069] Under vertical force, since the edge of the lower steel lining of the rubber pad is thin, this part is fully deformed and the test signal is obvious. Small lateral force or longitudinal force needs to be tested by the friction between the upper steel lining of the rubber pad and the bogie side frame. The large wheel force or longitudinal force is jointly borne by the sliding friction of the upper steel lining of the rubber pad and the upper positioning block. The modified axle box rubber pad structure can be effectively used for pasting stress sheets and assembling Wheatstone full bridges.

[0070] like Figure 3 As shown, step S1 includes the following steps:

[0071] S11, symmetrically cutting strip grooves along the edges of both long sides of the lower steel lining plate 803 of the original railway freight car bogie axle box rubber pad to obtain a first strip groove and a second strip groove symmetrically arranged on both long sides of the lower steel lining plate 803;

[0072] S12, a rectangular groove is opened at the central position of the surface of the upper steel liner 801 of the original railway freight car bogie axle box rubber pad to obtain a modified axle box rubber pad.

[0073] S2, patch the modified axle box rubber pad and assemble the bridge to obtain the axle box rubber pad carrying the Wheatstone full bridge group;

[0074] The step S2 comprises the following steps:

[0075] like Figure 4 As shown, S21, the first vertical force test strain gauge V1 and the second vertical force test strain gauge V2 are respectively pasted to the first strip groove position of the lower steel liner 803 of the modified axle box rubber pad, and the third vertical force test strain gauge V3 and the fourth vertical force test strain gauge V4 are respectively pasted to the second strip groove position of the lower steel liner 803 of the modified axle box rubber pad, wherein the first vertical force test strain gauge V1 and the second vertical force test strain gauge V2 are respectively arranged in one-to-one correspondence with the third vertical force test strain gauge V3 and the fourth vertical force test strain gauge V4;

[0076] S22, forming a first Wheatstone full bridge based on the first vertical force test strain gauge V1 and the second vertical force test strain gauge V2, and forming a second Wheatstone full bridge based on the third vertical force test strain gauge V3 and the fourth vertical force test strain gauge V4;

[0077] like Figure 5 As shown, S23, a first transverse friction test strain gauge L1 and a second transverse friction test strain gauge L2 are arranged along one side perpendicular to the horizontal direction of the rectangular groove of the upper steel liner 801 of the modified axle box rubber pad, and a third transverse friction test strain gauge L3 and a fourth transverse friction test strain gauge L4 are arranged along the other side perpendicular to the horizontal direction of the rectangular groove of the upper steel liner 801 of the modified axle box rubber pad, wherein the first transverse friction test strain gauge L1 and the second transverse friction test strain gauge L2 are arranged in one-to-one correspondence with the third transverse friction test strain gauge L3 and the fourth transverse friction test strain gauge L4, respectively, the first transverse friction test strain gauge L1 and the second transverse friction test strain gauge L2 are respectively at an angle of 45 degrees to one side of the horizontal direction of the rectangular groove of the upper steel liner 801 of the rubber pad, and the third transverse friction test strain gauge L3 and the fourth transverse friction test strain gauge L4 are respectively at an angle of 45 degrees to the other side of the horizontal direction of the rectangular groove of the upper steel liner 801 of the rubber pad;

[0078] like Figure 6 As shown, S24, a first longitudinal friction test strain gauge X1 and a second longitudinal friction test strain gauge X2 are arranged along one side perpendicular to the longitudinal direction of the rectangular groove of the upper steel liner 801 of the modified axle box rubber pad, and a third longitudinal friction test strain gauge X3 and a fourth longitudinal friction test strain gauge X4 are arranged along the other side perpendicular to the longitudinal direction of the rectangular groove of the upper steel liner 801 of the modified axle box rubber pad, wherein the first longitudinal friction test strain gauge X1 and the second longitudinal friction test strain gauge X2 are arranged in one-to-one correspondence with the third longitudinal friction test strain gauge X3 and the fourth longitudinal friction test strain gauge X4, respectively, and the first longitudinal friction test strain gauge X1 and the second longitudinal friction test strain gauge X2 are respectively at an angle of 45 degrees to one side of the longitudinal direction of the rectangular groove of the upper steel liner 801 of the rubber pad, and the third longitudinal friction test strain gauge X3 and the fourth longitudinal friction test strain gauge X4 are respectively at an angle of 45 degrees to the other side of the longitudinal direction of the rectangular groove of the upper steel liner 801 of the rubber pad;

[0079] S25, forming a third Wheatstone full bridge based on the first transverse friction test strain gauge L1, the second transverse friction test strain gauge L2, the third transverse friction test strain gauge L3 and the fourth transverse friction test strain gauge L4, and forming a fourth Wheatstone full bridge based on the first longitudinal friction test strain gauge X1, the second longitudinal friction test strain gauge X2, the third longitudinal friction test strain gauge X3 and the fourth longitudinal friction test strain gauge X4;

[0080] like Figure 7 and Figure 8 As shown, S26, respectively set the first positioning block vertical strain gauge D y1 and the first positioning longitudinal strain gauge D x1 , the second positioning vertical strain gauge D y2 and the second positioning block longitudinal strain gauge D x2 At both ends of the positioning block 804 on the left upper side of the modified axle box rubber pad, a third positioning block vertical strain gauge D is respectively provided. y3 And the third positioning block longitudinal strain gauge D x3 , the fourth positioning vertical strain gauge D y4 And the fourth positioning block longitudinal strain gauge D x4 Position the two ends of stopper 805 above the right side of the modified axle box rubber pad;

[0081] S27, based on the vertical strain gauge D of the first positioning block y1 , the second positioning vertical strain gauge D y2 , the third positioning vertical strain gauge D y3 And the fourth positioning vertical strain gauge D y4 The fifth Wheatstone full bridge is constructed, and based on the first positioning block longitudinal strain gauge Dx1 , the second positioning block longitudinal strain gauge D x2 , the third positioning block longitudinal strain gauge D x3 And the fourth positioning longitudinal strain gauge D x4 The sixth Wheatstone full bridge is assembled, and the axle box rubber pad carrying the Wheatstone full bridge group is obtained.

[0082] The Wheatstone full bridge group includes a first Wheatstone full bridge, a second Wheatstone full bridge, a third Wheatstone full bridge, a fourth Wheatstone full bridge, a fifth Wheatstone full bridge and a sixth Wheatstone full bridge;

[0083] like Fig. 9 , Fig.10 , Fig.11 , Fig.12 , Fig.13 and Fig.14 As shown, the output voltages of the first and second Wheatstone full bridges correspond to the wheel-rail vertical force, the output voltages of the third Wheatstone full bridge correspond to the lateral friction between the upper steel lining and the bogie side frame, the output voltages of the fourth Wheatstone full bridge correspond to the longitudinal friction between the upper steel lining and the bogie side frame, the output voltages of the fifth Wheatstone full bridge correspond to the lateral force acting between the left and right positioning blocks and the bogie side frame, and the output voltages of the sixth Wheatstone full bridge correspond to the lateral force acting between the left and right positioning blocks and the bogie side frame; the vertical force strain bridges correspond to the vertical, lateral and longitudinal loads respectively. The strain value variation curve of the increased strain value, the strain value variation curve of the lateral friction force strain bridge with the increase of vertical, lateral and longitudinal loads, the strain value variation curve of the longitudinal friction force strain bridge with the increase of vertical, lateral and longitudinal loads, the strain value variation curve of the upper positioning block lateral force strain bridge with the increase of vertical, lateral and longitudinal loads, and the strain value variation curve of the upper positioning block longitudinal force strain bridge with the increase of vertical, lateral and longitudinal loads can be obtained. Corresponding to different strain bridges, the force of the axle box rubber pad itself can be effectively measured when loads in different directions are applied;

[0084] S3, loading the axle box rubber pad carrying the Wheatstone full-bridge group in the transverse, longitudinal and vertical directions, and obtaining the proportional coefficients between the transverse, longitudinal and vertical loads and the output voltage signal of the Wheatstone full-bridge group respectively;

[0085] The step S3 comprises the following steps:

[0086] S31, the axle box rubber pad carrying the Wheatstone full bridge group is transversely loaded, and the transverse load F is obtained respectively. y The output voltage of the third Wheatstone full bridge is yf The proportionality coefficient k yf and the lateral load F y The fifth Wheatstone full-bridge output voltage ε yd The proportionality coefficient kyd ; It should be satisfied that the output voltage signal of the third Wheatstone full bridge and the output voltage signal of the fifth Wheatstone full bridge used for the lateral force test of the rubber pad are both linearly related to the lateral load, and the other Wheatstone full bridges are insensitive to the lateral load;

[0087] S32, longitudinal load the rubber pad of the axle box carrying the full Wheatstone bridge group, and obtain the longitudinal load F x The fourth Wheatstone full-bridge output voltage ε xf The proportionality coefficient k xf and longitudinal load F x The output voltage of the sixth Wheatstone full bridge ε xd The proportionality coefficient k xd ; It should be satisfied that the output voltage signal of the fourth Wheatstone full bridge and the output voltage signal of the sixth Wheatstone full bridge used for the longitudinal force test of the rubber pad are both linearly related to the longitudinal load, and the other Wheatstone full bridges are insensitive to the longitudinal load;

[0088] S33, vertically load the axle box rubber pad carrying the Wheatstone full bridge group, and obtain the vertical load F z The output voltage of the first Wheatstone full bridge is z1 The proportionality coefficient k z1 and vertical load F z The second Wheatstone full-bridge output voltage ε z2 The proportionality coefficient k z2 ; It should be satisfied that the output voltage signal of the first Wheatstone full bridge and the output voltage signal of the second Wheatstone full bridge used for the vertical force test of the rubber pad are both linearly related to the vertical load, and the other Wheatstone full bridges are insensitive to the vertical load;

[0089] S4. Based on the proportionality coefficients between the lateral, longitudinal and vertical loads and the output voltage signal of the Wheatstone full-bridge group, a force model of the axle box rubber pad carrying the Wheatstone full-bridge group is established;

[0090] The expression of the force model of the axle box rubber pad carrying the Wheatstone full bridge assembly in step S4 is as follows:

[0091]

[0092] S5. Based on the force model of the axle box rubber pad with the full Wheatstone bridge group, the mechanical model of the wheel-rail vertical force and the wheel-axle lateral force of the three major parts of the railway freight car bogie is established;

[0093] The expressions of the mechanical models of the wheel-rail vertical force and the wheel-axle lateral force of the three major components of the railway freight car in step S5 are as follows:

[0094] m w ·a z ·l c / 2+Fzl ·l c / 2-F zr ·l c / 2+G·l c / 2-Q l ·l c +H·r0=0

[0095] m w ·a z ·l c / 2+F zr ·l c / 2-F zl ·l c / 2+G·l c / 2-Q r ·l c -H·r0=0

[0096] H=F yl +F yr +m w ·a y

[0097] Where H is the lateral force of the wheel axle, F yl and F yr Respectively represent the lateral force on the rubber pad on the left side of the wheelset and the lateral force on the rubber pad on the right side of the wheelset, m w Indicates the wheelset mass, a y represents the lateral acceleration of the wheelset, a z represents the vertical motion acceleration of the wheelset, l c Indicates the lateral span of the left and right rubber pads of the wheelset, F zl and F zr They represent the vertical force of the rubber pad on the left side of the wheelset and the vertical force of the rubber pad on the right side of the wheelset, G represents the weight of the wheelset, and Q l and Q r They represent the left wheel-rail vertical force and the right wheel-rail vertical force respectively, and r0 represents the wheel radius;

[0098] like Fig.15 and 16 As shown, S6, the axle box rubber pads carrying the Wheatstone full bridge group are assembled to the left and right sides of the three-part bogie wheel set of the railway freight car, and the wheel-rail force test is carried out based on the mechanical model of the wheel-rail vertical force and the wheel-axle lateral force of the three-part bogie of the railway freight car, so as to complete the indirect test of the wheel-rail force of the three-part bogie of the railway;

[0099] The test results of this scheme are accurate. Compared with the mature force-measuring wheelset technology, the relative test error can be guaranteed to be within 10%. Compared with the traditional force-measuring wheelset technology and the force-measuring rail technology, the wheel-rail force of the freight car can be continuously monitored for a long time under braking conditions, and the test cost is much lower than that of the force-measuring wheelset. This method is suitable for large-scale equipment of freight trains. By real-time monitoring of the wheel-rail forces at multiple axle positions of freight trains, online evaluation of train operation safety can be achieved, and the operation of the train can be optimized to ensure the safe and punctual arrival of freight trains.

Claims

1. A method for indirect testing of wheel-rail forces of a railway freight car's three-part bogie, characterized in that: The steps include: S1. Reconstructing the rubber pads of the axle box of the original three major parts of the railway freight car bogie to obtain the reconstructed axle box rubber pads; The original railway freight car bogie axle box rubber pad includes an upper steel lining plate (801), a middle rubber layer (802), a lower steel lining plate (803), a positioning stopper (804) on the upper left side of the rubber pad, and a positioning stopper (805) on the upper right side of the rubber pad; S2. The modified axle box rubber pad patch and the bridge assembly are used to obtain the axle box rubber pad carrying the Wheatstone full bridge assembly, which is specifically: S21, affixing the first vertical force test strain gauge V1 and the second vertical force test strain gauge V2 to the first strip groove position of the lower steel lining plate (803), and affixing the third vertical force test strain gauge V3 and the fourth vertical force test strain gauge V4 to the second strip groove position of the lower steel lining plate (803); S22, forming a first Wheatstone full bridge based on V1 and V2, and forming a second Wheatstone full bridge based on V3 and V4; S23, a first transverse friction test strain gauge L1 and a second transverse friction test strain gauge L2 are arranged along one side perpendicular to the transverse direction of the rectangular groove of the upper steel lining plate (801), and a third transverse friction test strain gauge L3 and a fourth transverse friction test strain gauge L4 are arranged along the other side perpendicular to the transverse direction of the rectangular groove of the upper steel lining plate (801); S24, a first longitudinal friction test strain gauge X1 and a second longitudinal friction test strain gauge X2 are arranged along one side perpendicular to the longitudinal side of the rectangular groove of the upper steel lining plate (801), and a third longitudinal friction test strain gauge X3 and a fourth longitudinal friction test strain gauge X4 are arranged along the other side perpendicular to the longitudinal side of the rectangular groove of the upper steel lining plate (801); S25, forming a third Wheatstone full bridge based on L1, L2, L3 and L4, and forming a fourth Wheatstone full bridge based on X1, X2, X3 and X4; S26, respectively set the first positioning block vertical strain gauge D y1 and the first positioning longitudinal strain gauge D x1 , the second positioning vertical strain gauge D y2 and the second positioning block longitudinal strain gauge D x2 At both ends of the positioning block (804) on the left upper side of the rubber pad, a third positioning block vertical strain gauge D is respectively provided. y3 And the third positioning block longitudinal strain gauge D x3 , the fourth positioning vertical strain gauge D y4 And the fourth positioning block longitudinal strain gauge D x4 Position the two ends of the stopper (805) above the right side of the rubber pad; S27, based on D y1 , D y2 , D y3 and D y4 Build the fifth Wheatstone full bridge, based on D x1 , D x2 , D x3 and D x4 Assemble the sixth Wheatstone full bridge and obtain the axle box rubber pad carrying the Wheatstone full bridge assembly; S3, load the axle box rubber pad in three directions, namely, horizontally, longitudinally and vertically, to obtain the proportional coefficients between the three-direction loads and the output voltage signal of the Wheatstone full-bridge group; S4. Based on the proportional coefficient, a force model of the axle box rubber pad is established; S5. Based on the force model, establish the mechanical model of the wheel-rail vertical force and the wheel-axle lateral force of the three major parts of the railway freight car bogie; S6. Assemble the axle box rubber pads to the left and right sides of the bogie wheelsets of the three major parts of railway freight cars, and test the wheel-rail force according to the established mechanical model.

2. According to the indirect testing method for the wheel-rail force of the three-component bogie of a railway freight car according to claim 1, the step S1 comprises the following steps: S11, symmetrically cutting strip grooves along the edges of both long sides of the lower steel lining plate (803) of the original three-part bogie axle box rubber pad of a railway freight car to obtain a first strip groove and a second strip groove symmetrically arranged on both long sides of the lower steel lining plate (803); S12, a rectangular groove is made at the central position of the surface of the upper steel lining plate (801) of the original railway freight car bogie axle box rubber pad to obtain a modified axle box rubber pad, wherein: The middle rubber layer (802) is arranged above the lower steel lining plate (803); the upper steel lining plate (801) is arranged above the middle rubber layer (802); and the upper left positioning stop (804) of the rubber pad and the upper right positioning stop (805) of the rubber pad are arranged above the left and right ends of the upper steel lining plate (801) relatively.

3. The indirect test method for the wheel-rail force of the three-part bogie of a railway freight car according to claim 1 is characterized in that: The step S3 comprises the following steps: S31, the axle box rubber pad carrying the Wheatstone full bridge group is transversely loaded, and the transverse loads are obtained respectively. F y The third Wheatstone full-bridge output voltage The ratio coefficient between k yf and lateral load F y With the fifth Wheatstone full-bridge output voltage The ratio coefficient between k yd ; S32, longitudinal load the rubber pad of the axle box carrying the full Wheatstone bridge group, and obtain the longitudinal load F x With the fourth Wheatstone full-bridge output voltage The ratio coefficient between k xf and longitudinal load F x With the sixth Wheatstone full-bridge output voltage The ratio coefficient between k xd ; S33, vertical loading is performed on the axle box rubber pad carrying the full Wheatstone bridge assembly, and the vertical loads are obtained respectively. F z With the first Wheatstone full-bridge output voltage The ratio coefficient between k z1 and vertical load F z The second Wheatstone full-bridge output voltage The ratio coefficient between k z2 .

4. The indirect test method for the wheel-rail force of the three-part bogie of a railway freight car according to claim 3 is characterized in that: The expression of the force model of the axle box rubber pad carrying the Wheatstone full bridge assembly in step S4 is as follows: 。 5. The indirect test method for the wheel-rail force of the three-component bogie of a railway freight car according to claim 4 is characterized in that: The expressions of the mechanical models of the wheel-rail vertical force and the wheel-axle lateral force of the three major components of the railway freight car in step S5 are as follows: in, represents the lateral force on the wheel axle, and They represent the lateral force on the rubber pad on the left side of the wheelset and the lateral force on the rubber pad on the right side of the wheelset, Indicates the wheelset quality, represents the lateral acceleration of the wheelset, represents the vertical acceleration of the wheelset, Indicates the lateral span of the left and right rubber pads of the wheelset. and They represent the vertical force of the rubber pad on the left side of the wheelset and the vertical force of the rubber pad on the right side of the wheelset, represents the wheelset gravity, and They represent the left wheel-rail vertical force and the right wheel-rail vertical force respectively, Indicates the wheel radius.

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