JP4065831B2 - Creep force measuring device and method - Google Patents

Description

The present invention relates to equipment for measuring creep force acting between the railway rails and railway wheels (tangential force).

In railway technology, it is important to elucidate the effects of rail and wheel dynamic friction coefficients and the creep force ( tangential force) acting between them on derailment. Conventionally, as a device for measuring the dynamic friction coefficient of rails and wheels, for example, “Tribometer” and “μ Tester” manufactured by Railway Technical Research Institute are known. On the other hand, regarding the creep force, a method of measuring the slip ratio and the creep force using a two-cylinder rotation tester is known.

  The creep force is a force generated according to the slip rate of the rolling state of the wheel on the rail, and is assumed to be saturated to a value obtained by multiplying the normal force by the friction coefficient using the slip rate as a parameter. Furthermore, the creep force varies in saturation tendency depending on the contact state of the left and right wheels with the rail, the surface state of each wheel and rail, inclusions such as oil and water, or the rail longitudinal direction and width direction. I know that.

  The devices such as the “tribometer” and “μ tester” described above can measure the dynamic friction coefficient, but cannot measure the relationship between the slip ratio and the creep force (creep saturation characteristic). On the other hand, the two-cylinder rotary tester can measure the slip ratio and creep force, but the tester is large and limited to laboratory tests. Cannot be measured. Furthermore, although the present inventors conducted a creep force measurement test using a two-cylinder rotation tester, it was found that it was difficult to specify the influence of the friction coefficient in the factors that determine the creep force. Yes.

  For this reason, how the creep force saturation characteristic and the friction coefficient can change with changes in the surface condition of the actual rail-railway contact surface has not been fully understood at present. Accordingly, there is a need for an apparatus or method that can measure the creep force on an actual rail-railway wheel, and thus helps to clarify the influence of the creep force on derailment and the like.

  This invention is made | formed in view of such a situation, Comprising: It aims at providing the creep force measuring apparatus and method which can measure a creep force easily in an actual rail-railway wheel.

A creep force measuring device of the present invention is a creep force measuring device for measuring a creep force ( tangential force) acting between a railroad rail and a railroad wheel, the frame being fixed on the rail and extending in the longitudinal direction of the rail, A roller block driven along the longitudinal direction of the rail on the frame, guide means provided on the frame for guiding the roller block with low friction, and rotatably mounted on the roller block. A measuring roller that rolls in the longitudinal direction; a rotational angular velocity detecting means that detects a rotational angular velocity of the measuring roller; a moment applying means that applies a rotational moment to the measuring roller; and a moment detecting means that detects the rotational moment; The pressing force setting means for setting the pressing force of the measuring roller to the rail, and the pressing for detecting the pressing force It is characterized by comprising: a force detecting means; a driving speed detecting means for detecting the driving speed of the roller block; and a calculating means for calculating the creep force based on the detection value of each detecting means.

  According to the present invention, it is possible to easily measure the creep force in an actual rail-railway wheel. And, by combining the measurement result of creep force by this device with the measurement result of friction coefficient by devices such as “Trivometer” and “μ Tester” that have been provided in the past, the effect of creep force on derailment etc. is clarified You can also expect to be able to do it.

In creep force measuring device of the present invention, the calculating means, the slip rate s with respect to the rail of the measuring rollers, and can be further calculates an equivalent friction coefficient mu _e between the measuring roller and the rail.
In this case, the calculating means, the actual rail - slip ratio in the railway wheel s, since the equivalent friction coefficient mu _e can be calculated easily, the relationship between the slip ratio and the creep force (creep saturation characteristic) and the creep force saturation characteristics It can also be expected that the relationship with the friction coefficient can be clarified.

In the creep force measuring apparatus of the present invention, the roller block is driven by a driving mechanism provided in the frame, and the driving mechanism includes a motor-feeding mechanism that drives the roller block at a constant speed, and the roller block. Detecting means for detecting a movement limit point for the frame.
In this case, since the roller block can be driven at a constant speed, more accurate creep force measurement can be realized. And since this roller block detects a movement limit point by the detection means, it is possible to limit excessive movement of the roller block by automatically stopping the roller block according to this detection.

In the creep force measuring apparatus of the present invention, the moment applying means includes a pulley provided on the frame, a first wire spanned between the pulley and the measuring roller, and a spring provided on the frame. And a second wire bridged between the spring and the pulley.
Furthermore, the moment applying means can apply a moment to the measuring roller by the spring force of the spring that is pulled along with the rolling of the measuring roller.
When the measuring roller rolls on the rail, the pulley rotates through the first wire, and when the pulley rotates, the spring is pulled through the second wire. In this way, a moment due to the spring force is applied to the measuring roller via the wire pulley.

In the creep force measuring apparatus of the present invention, the frame may be provided with a fixing mechanism that detachably fixes the frame to the rail.
In this case, by using the fixing mechanism, it is possible to easily fix the apparatus to the rail and to release the fixing at the time of installation in another place.

  ADVANTAGE OF THE INVENTION According to this invention, the creep force measuring apparatus and method which can measure a creep force easily in an actual rail-railway wheel can be provided.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a conceptual diagram showing a creep force measuring apparatus according to an embodiment of the present invention.
FIG. 1 shows a conceptual configuration in a state in which the creep force measuring apparatus 1 according to this embodiment is fixed to a rail R. The creep force measuring apparatus 1 is roughly divided into the following parts.

(1) Frame 10.
(2) A creep force measuring unit including the roller block 20 assembled to the frame 10, and the measurement roller 30 attached to the roller block 20, the pressing force setting mechanism 40, and the block lifting mechanism 50.
(3) A drive mechanism 60 that drives the roller block 20 along the longitudinal direction of the rail R (the front-rear direction of the arrow in the figure).
(4) A moment application mechanism 70 that applies a rotational moment to the measurement roller 30.
(5) A fixing mechanism 90 that detachably fixes the frame 10 to the rail R.
(6) A limit switch unit 100 that detects a movement limit point of the roller block 20 with respect to the frame 10.
(7) A rotational angular velocity detection rotary encoder 81 for detecting the rotational angular velocity of the measuring roller 30, a driving speed detection rotary encoder 82 for detecting the driving speed of the roller block 20, a moment detection load cell 83 for detecting the rotational moment, and a pressing force are detected. A creep force calculation unit (calculation means) 80 that calculates a creep force based on each detection value of the pressing force detection load cell 84.

Hereinafter, the details of each part will be described with reference mainly to FIGS.
FIG. 2 is a left side view of the creep force measuring apparatus according to the present embodiment.
FIG. 3 is a right side view of the creep force measuring apparatus.
FIG. 4 is a top view of the creep force measuring apparatus.
5 is a cross-sectional view taken along the line II of FIG. 2 or FIG.
6 is a cross-sectional view taken along the line II-II in FIG. 2 or FIG.
FIG. 7 is a left side view showing details of a creep force measuring unit (roller block, measurement roller, pressing force setting mechanism, block lifting mechanism) of the creep force measuring apparatus.
FIG. 8 is a front cross-sectional view showing details of the lower part of the measurement unit in FIG. 7.

  In the following description, unless otherwise specified, the longitudinal direction of the rail (traveling direction of the vehicle) is the front-rear direction, the direction perpendicular to the rail longitudinal direction on the track surface is the left-right direction, and the direction perpendicular to the track surface is the up-down direction. Call. These directions are indicated by arrows in each figure.

(1) Frame 10
As shown in FIGS. 2 to 6, the frame 10 includes an upper plate 11. An elongated hole 11a is formed in the upper plate 11 (see FIG. 4). Standing plates 13 a to 13 d hang from the four corners of the upper plate 11. The lower ends of the left and right standing plates 13a and 13c, 13b and 13d are connected by a left side plate 15a and a right side plate 15b, respectively. Further, the lower ends of the two standing plates 13a and 13b and 13c and 13d are connected by connecting plates 17 and 18 (see FIGS. 5 and 6), respectively. In the state where the creep force measuring device 1 is installed on the rail R, the connecting plates 17 and 18 cross the rail R, and the vertical plates 13a and 13c, the left plate 15a, the vertical plates 13b and 13d, and the right plate 15b It will be in the state straddling the rail R.

(2) Creep Force Measuring Unit A creep force measuring unit having a roller block 20, a measuring roller 30, a pressing force setting mechanism 40, and a block lifting / lowering mechanism 50 is disposed inside the frame 10.
The roller block 20 of the creep force measuring unit has a rectangular parallelepiped outer shape. 6 to 8, the roller block 20 includes left and right side plates 21 and 22 and a top plate 23 that is bolted to the upper ends thereof. A measuring roller 30 is rotatably supported inside the roller block 20.

  As shown in FIG. 8, radial bearings 21 </ b> B and 22 </ b> B are incorporated in both side plates 21 and 22 of the roller block 20. A stepped shaft 25 is supported between the bearings 21B and 22B. The measuring roller 30 described above is fitted on the center of the stepped shaft 25. The stepped shaft 25 and the measurement roller 30 are fixed via a key 30a. Bushings 21C and 22C are fitted on the stepped shaft 25 between both side surfaces of the measuring roller 30 and the bearings 21B and 22B. The bushing pulleys 21D and 22D are fitted on the bushes 21C and 22C, respectively. Both winding pulleys 21 </ b> D and 22 </ b> D and the measuring roller 30 are coupled by screws 30 b. Therefore, both the winding pulleys 21D and 22D, the measuring roller 30, and the stepped shaft 25 rotate in synchronization with the rolling of the measuring roller 30 on the rail R.

  As shown in FIG. 8, an end plate 26 is screwed to the outer surface of the left side plate 21. A screw 27 with a knob is screwed into the end plate 26. The end of the knob-attached screw 27 is screwed into the left end 25R of the stepped shaft 25. The bearing 21 </ b> B and the stepped shaft 25 are prevented from coming off by the end plate 26 and the screw 27 with knob. On the other hand, a connection end 81H ′ of the housing 81H of the rotational angular velocity detection rotary encoder 81 is coupled to the outer surface of the right side plate 22. Inside the connecting end 81H ′ of the housing 81H, the right end 25L of the stepped shaft 25 and the rotating shaft 81a of the rotational angular velocity detecting rotary encoder 81 are connected via a boss 28. The rotational angular velocity detection rotary encoder 81 detects the rotational angular velocity of the measuring roller 30 and stores the data in the creep force calculation unit 80 in FIG. 1 (details will be described later).

As easily shown in FIGS. 4 to 7, the roller block 20 is provided with a pressing force setting mechanism 40 and a block lifting mechanism 50.
As best shown in FIG. 7, a slide frame 31 is fixed to the front surface of the roller block 20 via two brackets 32. The slide frame 31 is a U-shaped member extending in the vertical direction, and is disposed so as to vertically penetrate the elongated hole 11a of the upper plate 11 of the frame 10 described above (see FIG. 4). A screw guide 33A is fixed to the upper end side of the slide frame 31, and a screw 33B with a knob is screwed to the screw guide 33A. A standing plate 35 is provided below the screw guide 33A. The slide frame 31, the screw guide 33 </ b> A, the knob-attached screw 33 </ b> B, and the like constitute a block lifting mechanism 50 that moves the roller block 20 up and down with respect to the standing plate 35.

  The standing plate 35 provided on the lower side of the screw guide 33A is attached to the lower surface side of the upper plate 11 of the frame 10 as will be described later. The guide frame 31 and the roller block 20 slide up and down with respect to the standing plate 35. That is, when the knob-attached screw 33B is turned in the tightening direction, the screw guide 33A fitted to the knob 33B tends to move upward with respect to the standing plate 35. At this time, the guide frame 31 moves upward together with the screw guide 33A by a roller (not shown) accommodated in the guide frame 31. Conversely, when the knob screw 33B is turned in the loosening direction, the screw guide 33A moves downward relative to the standing plate 35, and the guide frame 31 moves downward together with the screw guide 33A. Such a block raising / lowering mechanism 50 is used when temporarily moving the entire roller block 20 upward when moving the entire creep force measuring apparatus 1 on the rail R.

  As shown in FIGS. 6 and 7, a support plate 41 is screwed to the upper part of the rear surface side of the upright plate 35. The above-described standing plate 35 is screwed to the horizontal plate 37 below the support plate 41. As shown in FIGS. 5 and 6, the horizontal plate 37 is a band-like member extending in the left-right direction, and is attached to the lower surface side of the upper plate 11 of the frame 10 via a linear guide (guide means) 39. . The linear guide 39 includes a fixed portion 39a fixed to the lower surface of the upper plate 11 of the frame 10 and a slide portion 39b that is slidably assembled to the lower side of the fixed portion 39a. Yes. The horizontal plate 37 moves in the front-rear direction with the slide portion 39 b of the linear guide 39 with respect to the frame 10. The upright plate 35 moves in the longitudinal direction in the elongated hole 11 a of the upper plate 11 of the frame 10 together with the horizontal plate 37 and the slide portion 39 b of the linear guide 39. The linear guide 39 plays a role of guiding the roller block 20 with low friction.

  As clearly shown in FIGS. 6 and 7, three connecting shafts 43 arranged at three points are bolted between the support plate 41 and the lateral plate 37. A screw shaft 45 is screwed into the support plate 41 at the center of these three points of the connecting shaft 43. As best shown in FIG. 6, a head 45a with a hexagonal hole is provided at the upper end of the screw shaft 45, and a sleeve 46 opened downward is fixed to the lower end. A contact bar 47 is accommodated in the sleeve 46. A flange portion 47 a is provided on the lower end side of the contact bar 47, and a pressing spring 49 is interposed between the flange portion 47 a and the sleeve 46 upper plate. The lower end of the contact bar 47 can be brought into contact with a pressing force detection load cell 84 fixed on the top plate 23 of the roller block 20 by receiving the biasing force of the pressing spring 49. The screw shaft 45, the sleeve 46, the contact bar 47, the pressing spring 49, and the like constitute a pressing force setting mechanism 40 that sets the pressing force of the measuring roller 30 against the rail R.

Here, the operation of the pressing force setting mechanism 40 will be described.
When a wrench or the like (not shown) is engaged with the head 45 a with a hexagonal hole of the screw shaft 45 and rotated, the screw shaft 45 advances downward while being screwed into the support plate 41. Then, the sleeve 46 that contacts the lower end of the screw shaft 45 moves downward while shrinking the pressing spring 49. In this case, the force with which the contact bar 47 presses the roller block 20 toward the rail R tread via the pressing force detection load cell 84 is set strongly. On the other hand, when the screw shaft 45 is turned to the opposite side, the screw shaft 45 advances upward, and the pressing spring 49 tends to extend between the sleeve 46 and the contact bar 47. Then, the sleeve 46 is pushed upward by this spring force, and the force with which the contact bar 47 presses the roller block 20 via the pressing force detection load cell 84 is weakened. The pressing force detection load cell 84 detects such pressing force, and stores the detected value in the creep force calculation unit 80 of FIG. 1 (details will be described later).

(3) Drive mechanism 60
As shown in FIG. 3, an L-shaped bracket 61 is fixed to the lower surface of the horizontal plate 37 on the right side of the roller block 20. A shaft holder 63 is fixed to the lower surface of the upper plate 11 of the frame 10 behind the L-shaped bracket 61. A rotating shaft 65 is held in the shaft holder 63 via two bearings 63a. A stepping motor 69 is connected to the rear end side of the rotating shaft 65 through a coupling 67. The stepping motor 69 is fixed to the lower surface of the upper plate 11 of the frame 10 via a motor holder 69A. A clean damper 69B is attached to the rear end of the stepping motor 69.

  On the other hand, a screw shaft 68 is connected to the front end side of the rotary shaft 65. A feed nut 62 is fitted on the screw shaft 68. The feed nut 62 is fixed to the L-shaped bracket 61 described above. The front end side of the screw shaft 68 is supported by a support frame 64 fixed to the lower surface of the upper plate 11 of the frame 10. A bearing (not shown) is interposed between the screw shaft 68 and the support frame 64. Further, a driving speed detection rotary encoder 82 is connected to the front end of the screw shaft 68 via a coupling 66.

  As described above, the horizontal plate 37 is attached to the lower surface of the upper plate 11 of the frame 10 via the linear guide 39 (see FIG. 5 and the like). Further, a vertical plate 35 is fixed to the horizontal plate 39, and the roller block 20 is attached to the vertical plate 35 via a slide frame 31 (see FIG. 7 and the like). Therefore, when the feed nut 62 fixed to the lower surface of the horizontal plate 37 via the L-shaped bracket 61 is screwed in the front-rear direction while being externally fitted to the screw shaft 68, the horizontal plate 37 is also moved in the front-rear direction at the same time. As the horizontal plate 37 moves, the upright plate 35, the slide frame 31, and the roller block 20 (creep force measurement unit) move in the front-rear direction while being guided by the linear guide 39.

  The drive mechanism 60 itself operates as follows. That is, as the stepping motor 69 is driven forward and backward, the rotary shaft 65 and the screw shaft 68 connected via the coupling 67 rotate forward and backward. Then, the feed nut 62 fitted on the screw shaft 68 is screwed and the roller block 20 moves in the front-rear direction as described above. The rotation of the screw shaft 68 is detected by a drive speed detection rotary encoder 82. The drive speed detection rotary encoder 82 detects the drive speed of the roller block 20 from the rotation of the screw shaft 68, and stores the detected value in the creep force calculation unit 80 of FIG. 1 (details will be described later).

(4) Moment applying mechanism 70
As shown in FIGS. 2 to 4, the moment application mechanism 70 includes a first wire 71. One end side (rear end side) of the first wire 71 is two, and is fixed to each of the winding pulleys 21D and 22D described above, and is wound up by a predetermined length. A moment detection load cell 83 is incorporated in the middle of the first wire 71. With the moment detection load cell 83 as a boundary, the other end side (front end side) of the first wire 71 is one. The other end of the first wire 71 is fixed to a large pulley 73 disposed behind the frame 10. The center of the large pulley 73 is fixed to the shaft 75 by external fitting. As clearly shown in FIG. 4, two small pulleys 74 are fixed to the shaft 75 on both sides of the large pulley 73. One end of a second wire 72 is fixed to each of these small pulleys 74.

  As clearly shown in FIG. 4, a pair of moment applying springs 76 corresponding to the small pulleys 74 and the second wires 72 are disposed on the upper surface of the upper plate 11 of the frame 10. Each moment imparting spring 76 is accommodated in a cylindrical spring holder 78 and arranged in a state of lying parallel to each other. Each moment applying spring 76 has a fixed end portion 76b fixed to the holder block 78A on the rear end side, and a free end portion 76a on the front end side. The other end side of each second wire 72 extends through the inside of each moment applying spring 76, and the end is fixed to the free end 76 a of the moment applying spring 76.

  Both ends of the shaft 75 to which the large and small pulleys 73 and 74 are fitted and fixed are supported by the horizontal support bar 77B and the vertical support bar 77C via the boss 77A. As shown in FIG. 4, the lateral support rod 77 </ b> B is connected to the standing plates 13 c and 13 d of the frame 10. As shown in FIGS. 2 and 3, the vertical support rod 77C is connected to the left and right side plates 15a and 15b. The horizontal support bar 77B and the vertical support bar 77C support the large and small pulleys 73 and 74 and the shaft 75 on the frame 10 so as to be rotatable.

  Such a moment applying mechanism 70 applies a moment to the measuring roller 30 when the roller block 20 is driven. Specifically, when the roller block 20 moves to the front side by driving the drive mechanism 60, the measuring roller 30 rolls in the direction of arrow X in FIG. Along with this, the winding pulleys 21 </ b> D and 22 </ b> D that are coaxially fixed to the measuring roller 30 rotate and gradually wind up the first wire 71. When the first wire 71 is stretched to some extent, the large pulley 73 rotates in the direction of the arrow X ′ in FIG. 2, and both small pulleys 74 also rotate in the same X ′ direction, and the second wire 72 is moved backward. The moment applying spring 76 is contracted by being pulled to the side.

  In such an operation, while the frictional force between the rail R and the measuring roller 30 is larger than the spring force of the moment applying spring 76, the measuring roller 30 continues to roll on the rail R, and the first wire 71 is wound up. While being wound around the pulleys 21 </ b> D and 22 </ b> D, the second wire 72 is pulled and the moment applying spring 76 is contracted. A moment is applied to the measuring roller 30 by the spring force of the moment applying spring 76 at this time. Thereafter, when the spring force of the contracted moment applying spring 76 becomes larger than the frictional force between the rail R and the measuring roller 30, the moment applying spring 76 extends and pulls the second wire 72 forward, and the large and small pulleys 73 and 74 are stretched. Is rotated in the direction of arrow Y 'in FIG. As the large and small pulleys 73 and 74 rotate, the first wire 71 is pulled rearward to rotate the take-up pulleys 21D and 22D, and the measurement roller 30 that is coaxially fixed with the take-up pulleys 21D and 22D also rotates. . This moment (the tensile force of the first wire 71 at the time when the measuring roller 30 is pulled and starts rotating) is detected by the moment detection load cell 83. The moment detection load cell 83 detects this moment (tensile force) and stores the data in the creep force calculation unit 80 of FIG. 1 (details will be described later).

(5) Fixing mechanism 90
As best shown in FIG. 5, the fixing mechanisms 90 are provided at the four corners at the bottom of the frame 10. The left two fixing mechanisms 90L and the right two fixing mechanisms 90R have slightly different configurations.
The left fixing mechanism 90L includes a pair of rocking plates 91L having a dogleg shape. Both swing plates 91L are supported by a shaft 92L so as to be swingable at the central bent portion. A roller 93L is held at the lower end between both swing plates 91L. A screw 95 with a knob is attached to the upper ends of both swing plates 91L. On the other hand, the right fixing mechanism 90R is similarly provided with a swing plate 91R, a shaft 92R, and a roller 93R, but a hexagon socket head bolt 96 is provided instead of the knob screw 95 in the left fixing mechanism 90L. Yes.

  When the frame 10 of the creep force measuring apparatus 1 is fixed to the rail R, the right fixing mechanism 90R is set in a fixed state, and the screw 95 with a knob of the left fixing mechanism 90L is set in a tightened state. Then, when the roller 93R of the right fixing mechanism 90R is applied to the rail R side and the frame 10 is placed on the rail R, and the screw 95 with the knob of the left fixing mechanism 90L is gradually loosened, the shaft 92L swings around the shaft 92L. The plate 91L swings and the roller 93L approaches the rail R side. When the screw 95 with the knob is further loosened, the rail R is sandwiched between the rollers 93L and 93R of the left and right fixing mechanisms 90L and 90R, and the creep force measuring device 1 is fixed to the rail R. On the contrary, when removing the creep force measuring apparatus 1 from the rail R, the knob screw 95 is loosened so that the roller 93L is separated from the rail R side.

(6) Limit switch unit 100.
2 to 4, a long detection plate 101 and a short detection plate 102 are attached to both side surfaces of the upper plate 11 of the frame 10. On the other hand, as shown in FIGS. 2, 3, 5, and 6, limit switch portions 100 are attached to both end surfaces of the horizontal plate 37. These limit switch sections 100 have substantially the same configuration. The left long detection plate 101 and limit switch unit 100 detect the long distance movement limit point of the roller block 20, and the right short detection plate 102 and limit switch unit 100 detect the short distance movement limit point of the roller block 20. By using both in combination, it is possible to determine the movement start point and the movement end point of the roller block 20. Each limit switch unit 100 is connected to the stepping motor 69 of the drive mechanism 60 described above. The stepping motor 69 is automatically stopped when the limit point of the limit switch unit 100 is detected.

(7) Creep force calculation unit 80
As conceptually shown in FIG. 1, the creep force calculation unit 80 stores each detection value of the rotational angular velocity detection rotary encoder 81, the drive speed detection rotary encoder 82, the moment detection load cell 83, and the pressing force detection load cell 84, Based on these detection values, the creep force is calculated by the following steps 1 to 4.

Step 1: From the radius r of the measuring roller 30 and the detected value of the rotational angular velocity detection rotary encoder 81 (rotational angular velocity ω when the measuring roller 30 rolls on the rail R), the peripheral speed V _{W of the} measuring roller 30 = R · ω is calculated.
Step 2: since the peripheral velocity V _W of the measuring rollers 30 calculated in step 1, the detection value of the drive speed detection rotary encoder 82 (the driving speed V _t of the roller block _20), the slip ratio with respect to the rail R of the measuring roller 30 s = (V _t −V _W ) / V _t is calculated.
Step 3: The detection value of the moment detection load cell 83 (tangential force f with respect to the rail R of the measuring roller 30 based on the moment applying mechanism 70) and the detection value of the pressing force detection load cell 84 (set by the pressing force setting mechanism 40). From the normal force N) of the measuring roller 30 to the rail R, an equivalent friction coefficient μ _e = f / N between the measuring roller 30 and the rail R is calculated.
Step 4: slip rate s calculated in step 2, and, based on the equivalent friction coefficient mu _e calculated in step 3, to calculate the creep force.

More specifically, the creep force calculation unit 80 calculates the creep force as follows.
(A) The setting parameters are as follows.
Set speed of the roller block 20 driven by the drive mechanism 60: V (unit: cm / s)
-Contact circle diameter of the measuring roller 30 with respect to the rail R: _Dw (unit: m)
Moment applied tensile diameter measuring roller 30 to be pulled by the mechanism 70: _{D s} (unit m)
-Number of pulses of the rotary angular velocity detection rotary encoder 81: _Pw
Drive pulse width of the stepping motor 69 of the drive mechanism 60: W _t (unit m / rot)
・ Sampling frequency: f _s (unit: Hz)
・ Speed calculation reference clock: S _B (unit: Hz)

(B) The measurement parameters are as follows.
-Speed count number of measuring roller 30: _nw
-Speed count of roller block 20: n _t
· Pressing load voltage in the pressing force detecting load cell 84: _{x t} (Unit V)
-Spring tension load voltage in moment detection load cell 83: x _s (unit: V)
-Position count of measuring roller 30: nd _W
-Position count of roller block 20: nd _t
・ Tensile force of measuring roller: F _S (unit: N)

(C) Monitor output prepares 3 screens, and displays the following graphs respectively.
・ The first screen shows the horizontal axis: slip rate s and the vertical axis: equivalent friction coefficient μ _e
-The second screen shows the horizontal axis: time t, the vertical axis: the speed V _{t of} the roller block 20, and the speed V _{W of the} measuring roller 30.
・ The third screen shows horizontal axis: time t, vertical axis: pressing force N _t of the measuring roller 30 and tangential force T

(D) The arithmetic expressions are as follows (a) to (g).
(A) Roller block travel distance d _t = nd _t · W _t (unit: m)
(B) Measuring roller travel distance d _W = nd _W · π · D _W / P _W (unit: m)
(C) Measuring roller speed V _W = (π · D _W · S _B ) / (n _W · P _W ) (unit: m / s)
(D) Roller block speed V _t = W _t · (S _B / n _W ) (unit: m / s)
(E) Slip rate s = (V _t −V _W ) / V _t
(F) the tangential force _{T = F S · (D s} / D W) ( unit N)
(G) Equivalent friction coefficient μ _e = T / N _t

Here, the overall operation of the creep force measuring apparatus 1 will be described.
First, the frame 10 of the creep force measuring device 1 is placed at a predetermined position on the rail R, and the frame 10 is fixed to the rail R using the fixing mechanism 90. Next, the block raising / lowering mechanism 50 attached to the roller block 20 is operated to lower the measurement roller 30 until it comes into contact with the upper surface of the rail R, and then the pressing force setting mechanism 40 is operated to normal the measurement roller 30 to the rail R. Set force N.

  Next, the drive mechanism 60 is driven to move the roller block 20 at a constant speed along the rail R longitudinal direction (front side). At this time, the measuring roller 30 rolls in the direction of arrow X in FIG. 2 while being in sliding contact with the upper surface of the rail R, and the first wire 71 is gradually wound around the winding pulleys 21D and 22D. When the first wire 71 is stretched to some extent, the large pulley 73 and the small pulley 74 rotate in the direction indicated by the arrow X ′ in FIG. 2 and the second wire 72 is pulled rearward, and the moment applying spring 76. The moment is applied to the measuring roller 30 by the spring force of the moment applying spring 76. Thereafter, when the spring force of the contracted moment applying spring 76 becomes larger than the frictional force between the rail R and the measuring roller 30, the moment applying spring 76 extends and pulls the second wire 72 forward, and the large and small pulleys 73 and 74 are stretched. 2 is rotated in the direction of arrow Y ′ in FIG. 2, and the measuring roller 30 is pulled by the first wire 71 and rotated.

  The movement of the roller block 20 is detected by the limit switch unit 100. When the limit switch unit 100 detects the movement limit point and the stepping motor 69 of the drive mechanism 60 stops, the roller block 20 also stops. Then, during the movement of the roller block 20, the creep force calculation unit 80 performs the creep force according to steps 1 to 4 based on the detection values detected in the rotary encoders 81 and 82 and the load cells 83 and 84. Is calculated.

Hereinafter, specific numerical examples will be described.
In this example, the actual railway wheel conditions assumed were taken into consideration, and the radius r of the measuring roller was set to 30 mm and the pressing load N was set to 30 kgf. In this case, the contact circle radius is 0.388 mm and the Hertz pressure is 932 MN / m ² . This condition corresponds to, for example, a case where a wheel having a radius of 430 mm contacts at a portion having a rail head radius of 80 mm, and the Hertz pressure is 1.79 GN / m ² when the wheel load is 6500 kgf. The Hertz pressure in the measurement roller having the radius r = 30 mm corresponds to the contact force of the vehicle having an actual wheel load of about 3.4 t.

With respect to the moment applying spring 76 of the moment applying mechanism 70, the friction coefficient μ _E with respect to the rail R of the measuring roller 30 is 0.3, 0.5 with respect to a certain pressing force N that can be set by the pressing force setting mechanism 40. It was assumed that each value of 0.7 was taken. Then, for each of these assumed friction coefficients μ _E = 0.3, 0.5, 0.7, each spring constant k was calculated based on the following formula:
k = μ _E · N / L.
However, L is the moving distance of the roller block 20.

Then, using the moment applying spring 76 of the spring force F having the spring constant k, the friction coefficient μ between the measuring roller 30 and the rail R was calculated based on the following formula:
μ = (D _s / D _W ) · (F / N).
However, D _s is the tensile diameter (unit m) of the measuring roller 30 pulled by the moment applying mechanism 70 in the setting parameter (A) described above, and D _W is the diameter of the contact circle of the measuring roller 30 with respect to the rail R ( Unit m). For example, the tensile diameter D _s can be set to 40 mm.

It is a conceptual diagram which shows the creep force measuring apparatus which concerns on one Example of this invention. It is a left view of the creep force measuring apparatus which concerns on a present Example. It is a right view of the creep force measuring device. It is a top view of the creep force measuring apparatus. It is the II sectional view taken on the line of FIG. 2 or FIG. It is the II-II sectional view taken on the line of FIG. It is a left view which shows the detail of the creep force measurement part (a roller block, a measurement roller, pressing force setting mechanism, a block raising / lowering mechanism) of the creep force measuring apparatus. It is front sectional drawing which shows the detail of the lower part of the measurement part of FIG.

Explanation of symbols

R rail 1 Creep force measuring device 10 Frame 20 Roller block 30 Measuring roller 39 Linear guide 40 Pressing force setting mechanism 45 Screw shaft 46 Sleeve 47 Contact bar 49 Pressing spring 50 Block lifting mechanism 60 Drive mechanism 62 Feed nut 68 Screw shaft 69 Stepping motor 70 Moment applying mechanism 71 First wire 72 Second wire 73 Large pulley 74 Small pulley 75 Shaft 76 Moment applying spring 80 Creep force calculation unit 81 Rotational angular velocity detection rotary encoder 82 Drive velocity detection rotary encoder 83 Moment detection load cell 84 Pushing force detection load cell 90R, 90L Fixing mechanism 100 Limit switch part 101 Long detection plate 102 Short detection plate

Claims (7)

A creep force measuring device for measuring a creep force ( tangential force) acting between a railway rail and a railway wheel,
A frame fixed on the rail and extending in the rail longitudinal direction;
A roller block driven along the longitudinal direction of the rail on the frame;
Guide means provided on the frame for guiding the roller block with low friction;
A measurement roller that is rotatably attached to the roller block and rolls on the rail in the rail longitudinal direction;
Rotation angular velocity detection means for detecting the rotation angular velocity of the measuring roller;
Moment applying means for applying a rotational moment to the measuring roller;
Moment detecting means for detecting the rotational moment;
A pressing force setting means for setting a pressing force to the rail of the measuring roller;
A pressing force detecting means for detecting the pressing force;
Driving speed detecting means for detecting the driving speed of the roller block;
Calculation means for calculating the creep force based on detection values of the detection means;
A creep force measuring device comprising: The calculating means, the slip rate s with respect to the rail of the measuring roller, and the creep force measuring apparatus according to claim 1, wherein the further calculates the equivalent friction coefficient mu _e between the measuring roller and the rail. The roller block is driven by a drive mechanism provided in the frame;
The drive mechanism is
A feed mechanism with a motor for driving the roller block at a constant speed;
Detecting means for detecting a movement limit point of the roller block with respect to the frame;
The creep force measuring device according to claim 1 or 2 , further comprising: The moment applying means is
A pulley provided on the frame;
A first wire spanned between the pulley and the measuring roller;
A spring provided on the frame;
A second wire spanned between the spring and the pulley;
The creep force measuring device according to any one of claims 1 to 3 , further comprising: 5. The creep force measuring apparatus according to claim 4 , wherein the moment applying means applies a moment to the measuring roller by a spring force of the spring that is pulled as the measuring roller rolls. A creep force measuring device for measuring a creep force ( tangential force) acting between a railway rail and a railway wheel,
A frame fixed on the rail and extending in the rail longitudinal direction;
A roller block driven along the longitudinal direction of the rail on the frame;
Guide means provided on the frame for guiding the roller block with low friction;
A measurement roller that is rotatably attached to the roller block and rolls on the rail in the rail longitudinal direction;
Has a spring which with tensile et al rolling of the measurement roller, and moment application means for applying a moment to the measurement roller by the spring force of the spring,
A creep force measuring device comprising: The creep force measuring device according to any one of claims 1 to 6, wherein a fixing mechanism for detachably fixing the frame to the rail is provided on the frame.

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