Rotational contact testing device and slip ratio adjustment device

Abstract

To provide a rotary contact testing device and a slip ratio adjustment device that can easily adjust a slip ratio with high accuracy in a stepless manner by a power generation unit with low output.SOLUTION: A rotary contact testing device 3 is a device that performs a test by bringing a circumference surface of a rail test piece 1 and a circumference surface of a wheel test piece 2 into rotary contact with each other by the power generated by a power generation unit 5. The rotary contact testing device 3 includes: an adjustment power generation unit 17 that generates adjustment power to adjust a slip ratio between the circumference surface of the rail test piece 1 and the circumference surface of the wheel test piece 2 on the outside of a power circulation path where the power generated by the power generation unit 5 circulates; and a rotational speed adjustment unit 20 that adjusts a rotational speed of the wheel test piece 2 in a stepless manner by receiving input of the power generated by the power generation unit 5 and the adjustment power generated by the adjustment power generation unit 17 and outputting the power to make the slip ratio a prescribed slip ratio. The rotational speed adjustment unit 20 is an inscription type planetary gear transmission device using a trochoid type tooth shape.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a rotational contact test apparatus that performs a test by rotationally contacting the circumferential surfaces of a first rotating body and a second rotating body with the power generated by a power generation unit, and a slip ratio adjustment apparatus that adjusts the slip ratio between the circumferential surfaces of the first rotating body and the second rotating body that rotate in contact with each other by the power generated by the power generation unit.

Background Art

[0002] Conventionally, there have been rolling test apparatuses involving slip, such as test apparatuses for rolling friction, wear, and rolling fatigue. Representative forms of this rolling test apparatus include a two-cylinder rolling test apparatus and a Western-style wear test apparatus. The conventional two-cylinder rolling test apparatus includes a motor that rotates the rotation axis of a wheel test wheel and a motor that rotates the rotation axis of a rail test wheel (see, for example, Patent Document 1). Power is generated for this purpose. The conventional two-cylinder rolling test apparatus rotates each rotation axis with each motor and conducts a test with the wheel test wheel and the rail test wheel in contact. The conventional Western-style wear test apparatus includes a prime mover that rotates the input shaft of a test gear transmission, a circulating gear transmission that circulates the power from the output shaft of this test gear transmission, and a load generation gear transmission that inputs the power from the circulating gear transmission to the input shaft of a supply gear transmission (see, for example, Patent Document 2). The conventional Western-style wear test apparatus uses the power from one prime mover to rotate the two gears of the test gear transmission at different speeds by the load generation gear transmission, causing slip between the two gears to conduct a wear test.

[0003] The conventional wheel testing apparatus 103 shown in Figure 14 includes a first electric motor 105 that rotates the rail wheel 101 and the test wheel 102 while they are in contact, and a torque generating device 117 that generates torque on the test wheel 102 so that slippage occurs between the rail wheel 101 and the test wheel 102 (see, for example, Patent Document 3). In the conventional wheel testing apparatus 103, the torque generating device 117 is equipped with a second electric motor 120 within a rotating frame 104 that is rotationally driven by the first electric motor 105, and at least one of the rail wheel 101 or the test wheel 102 is connected via the torque generating device 117. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 63-198848

[0005] [Patent Document 2] Japanese Patent Application Publication No. 07-260628

[0006] [Patent Document 3] International Publication No. 2021 / 225133 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] Conventional two-cylinder rolling contact testing equipment is a rolling test machine that uses two motors, so when slippage is induced, one motor generates the driving force and the other generates the braking force. For this reason, conventional two-cylinder rolling contact testing equipment requires high-output motors when testing large frictional forces. Furthermore, conventional two-cylinder rolling contact testing equipment has the drawback that the slip ratio depends on the rotational accuracy of the two motors, making it difficult to stabilize the slip ratio. In conventional two-cylinder rolling contact testing equipment, frictional force is a physical phenomenon that varies over time, so even with highly responsive control, the slip ratio will fluctuate to some extent, making it difficult to stabilize the slip ratio and control it with high precision.

[0008] Conventional Nishihara-type wear testing devices utilize a mechanism that recycles braking force into driving force. Therefore, conventional Nishihara-type wear testing devices can perform tests with large frictional forces using low-power motors. However, in conventional Nishihara-type wear testing devices, the mechanism that circulates braking force as driving force relies on gears and shafts, and the slip ratio is determined by the gear tooth ratio. Consequently, while the slip ratio can be kept constant in conventional Nishihara-type wear testing devices, it cannot be continuously varied.

[0009] In the conventional wheel testing device 103 shown in Figure 14, the first motor 105 rotates the rotating frame 104, and the second motor 120 inside the rotating frame 104 rotates the test wheel 102 while rotating together with the rotating frame 104, thereby creating slip between the test wheel 102 and the rail wheel 101. Therefore, in the conventional wheel testing device 103, the second motor 120 itself rotates together with the rotating frame 104, requiring a special motor with low inertia and high output for the second motor 120, and power must be supplied to the rotating second motor 120 by a slip ring, which results in a complex device.

[0010] The object of this invention is to provide a rotary contact testing apparatus and a slip ratio adjustment apparatus that can easily and precisely adjust the slip ratio steplessly using a low-power power generation unit. [Means for solving the problem]

[0011] This invention solves the aforementioned problem by the following means of solution. The embodiments of this invention will be described using corresponding reference numerals, but the invention is not limited to these embodiments. The invention of claim 1 is a rotary contact testing apparatus (3) that performs a test by bringing the circumferential surface of a first rotating body (1) and the circumferential surface of a second rotating body (2) into rotational contact using power generated by a power generating unit (5), as shown in Figures 2 and 4, and comprises: an adjustment power generating unit (17) that generates adjustment power to adjust the slip ratio between the circumferential surface of the first rotating body and the circumferential surface of the second rotating body, outside the power circulation path (R) through which the power generated by the power generating unit circulates; and a rotation speed adjustment unit (20) that receives the power generated by the power generating unit and the adjustment power generated by the adjustment power generating unit, and outputs power to make the slip ratio a predetermined slip ratio, thereby continuously adjusting the rotation speed of the second rotating body.

[0012] The invention of claim 2 is a rotary contact testing apparatus according to claim 1, characterized in that the rotational speed adjustment unit is a planetary gear speed change device that continuously adjusts the rotational speed of the second rotating body.

[0013] The invention of claim 3 is a rotational contact testing apparatus according to claim 1, characterized in that, as shown in Figures 6 and 7, the rotational speed adjustment unit is an internal planetary gear speed change device using a trochoidal tooth profile.

[0014] The invention of claim 4 is a rotary contact testing apparatus according to claim 1, characterized in that, as shown in Figure 13, the rotational speed adjustment unit is a harmonic drive gear that utilizes the differential generated by the meshing of a circular internal gear (20k) and an elliptical external gear (20m).

[0015] The invention of claim 5 is a rotary contact testing apparatus according to claim 1, characterized in that it includes a contact position changing unit (13) that changes the contact position (P) between the circumferential surface of the first rotating body and the circumferential surface of the second rotating body in the direction of the centerlines (O1, O2) of the first and second rotating bodies, as shown in Figures 2 and 5.

[0016] The invention of claim 6 is a rotary contact testing apparatus according to claim 1, characterized in that it comprises a supply unit (31) that supplies a feed material (M) between the circumferential surface of the first rotating body and the circumferential surface of the second rotating body, as shown in Figures 2 and 8.

[0017] The invention of claim 7 is a rotary contact testing apparatus according to claim 1, characterized in that it is equipped with a wavy wear suppression unit (32) that suppresses the occurrence of wavy wear of a specific wave number on the circumferential surface of the first and / or second rotating body, as shown in Figures 2 and 10.

[0018] The invention of claim 8 is a rotary contact testing apparatus according to claim 1, characterized in that it is equipped with a load generating unit (33) that generates a predetermined load so that a contact force acts on the contact position (P) between the circumferential surface of the first rotating body and the circumferential surface of the second rotating body, as shown in Figures 2, 8, and 9.

[0019] The invention of claim 9 is a rotary contact testing apparatus according to claim 8, characterized in that it is further equipped with a contact force fluctuation suppression unit (34) that suppresses fluctuations in the contact force acting at the contact position.

[0020] The invention of claim 10 is a rotary contact testing apparatus as described in claim 9, characterized in that the contact force fluctuation suppression unit comprises a plurality of types of elastic parts (34c) with different spring constants, and these elastic parts are detachable and replaceable.

[0021] The invention of claim 11 is a rotary contact testing apparatus according to claim 1, characterized in that it is equipped with an inclination angle changing unit (36) that changes the inclination angle such that the center line (O2) of the second rotating body (2) with respect to the center line (O1) of the first rotating body (1) is at a predetermined inclination angle (θ), as shown in Figures 8, 11, and 12.

[0022] The invention according to claim 12 is a rotational contact test apparatus according to claim 1, wherein, as shown in FIG. 1, the first rotating body is a cylindrical rail test piece (1) simulating an actual rail, and the second rotating body is a circular wheel test piece (2) that makes rotational contact with the outer peripheral portion of the rail test piece and simulates an actual wheel. The rotational contact test apparatus is characterized by this.

[0023] The invention according to claim 13 is a slip ratio adjustment device that adjusts the slip ratio between the circumferential surface of a first rotating body (1) and the circumferential surface of a second rotating body (2) that make rotational contact by the power generated by a power generation unit (5), as shown in FIGS. 2, 4, and 6. Outside the power circulation path (R) through which the power generated by the power generation unit circulates, there is an adjustment power generation unit (17) that generates adjustment power for adjusting the slip ratio, and the power generated by the power generation unit and the adjustment power generated by the adjustment power generation unit are input. The slip ratio adjustment device (16) includes a rotational speed adjustment unit (20) that outputs power for making the slip ratio a predetermined slip ratio, thereby adjusting the rotational speed of the second rotating body steplessly.

Effect of the Invention

[0024] According to this invention, the slip ratio can be easily adjusted steplessly with high precision by a low-output power generation unit.

Brief Description of the Drawings

[0025] [Figure 1] It is an external view schematically showing a wheel test piece and a rail test piece used in the rotational contact test apparatus according to the first embodiment of this invention. (A) is a front view, (B) is a cross-sectional view showing the state cut along line I-IB of (A), and (C) is a schematic view of the contact surface of the wheel test piece and the rail test piece when looking at the I-IC portion of (A) from below. [Figure 2] It is a front view schematically showing the rotational contact test apparatus according to the first embodiment of this invention. [Figure 3] It is a configuration diagram schematically showing the rotational contact test apparatus according to the first embodiment of this invention. [Figure 4]This is a schematic conceptual diagram illustrating the power circulation of a rotary contact testing apparatus according to the first embodiment of this invention. [Figure 5] This is a schematic diagram illustrating the operation of the contact position changing section of the rotary contact testing apparatus according to the first embodiment of this invention, where (A) is a schematic diagram showing the state in which the rail test piece is advanced, and (B) is a schematic diagram showing the state in which the rail test piece is retracted. [Figure 6] This is a schematic diagram of the rotational speed adjustment section of a rotary contact testing apparatus according to the first embodiment of the present invention. [Figure 7] This is a schematic diagram showing the case where the rotational speed adjustment unit of the rotary contact testing apparatus according to the first embodiment of this invention is an internal planetary gear system using a trochoidal tooth profile. [Figure 8] This is a schematic diagram showing a part of the holding portion of a rotary contact testing device according to the first embodiment of this invention, with the portion broken off. [Figure 9] Figure 8 is a cross-sectional view showing the state after cutting along the line IX-IX. [Figure 10] This is a schematic front view showing the contact force fluctuation suppression unit and the inclination angle changing unit of the rotary contact testing apparatus according to the first embodiment of the present invention. [Figure 11] This is a schematic diagram illustrating the operation of changing the inclination angle by the inclination angle changing unit of the rotary contact testing apparatus according to the first embodiment of this invention, where (A) is a schematic diagram showing the state before changing the inclination angle, and (B) is a schematic diagram showing the state after changing the inclination angle. [Figure 12] This is a plan view showing the state of a wheel test piece before and after tilting due to the tilt angle changing section of the rotary contact testing apparatus according to the first embodiment of this invention, where (A) is a plan view showing the state before the tilt angle is changed, and (B) is a plan view showing the state after the tilt angle is changed. [Figure 13] This is a schematic diagram showing the case where the rotational speed adjustment unit of the rotary contact testing apparatus according to the second embodiment of this invention is a harmonic drive gear. [Figure 14] This is a conceptual diagram illustrating the power circulation of a conventional wheel testing device. [Modes for carrying out the invention]

[0026] (First Embodiment) A first embodiment of this invention will be described in detail below with reference to the drawings. The rail test specimen 1 shown in Figure 1 is a cylindrical rotating body that simulates an actual rail. The rail test specimen 1 is an inner ring test specimen that is cut from an actual railway rail and processed into a cylindrical (disc) shape, or manufactured in a cylindrical (disc) shape from the same material as an actual railway rail. The rail test specimen 1 has an outer circumferential surface 1a that contacts the wheel test specimen 2, and the outer circumferential surface 1a is formed as a straight, flat surface in cross-section. The rail test specimen 1 rotates around the center line O1.

[0027] The wheel test piece 2 is a circular rotating body that simulates a real wheel and rotates in contact with the outer circumference of the rail test piece 1. The wheel test piece 2 is an outer ring test piece that is cut from a wheel of a real railway vehicle and processed into a circular (annular) shape, or manufactured into a circular (annular) shape from the same material as a wheel of a real railway vehicle. The wheel test piece 2 has an inner circumferential surface 2a on its inner circumference that contacts the rail test piece 1, and the cross-sectional shape of the inner circumferential surface 2a is formed as an arc-shaped curved surface so as to make line contact with the outer circumferential surface 1a on the rail test piece 1 side. The wheel test piece 2 rotates around a center line O2 that is slightly offset from the center line O1 and parallel to the center line O1.

[0028] The contact position P is the position where the circumferential surface of the rail test piece 1 and the circumferential surface of the wheel test piece 2 come into contact. The contact surface S is the region where the circumferential surface of the rail test piece 1 and the circumferential surface of the wheel test piece 2 rotate and come into contact at the contact position P. The contact surface S becomes approximately circular, approximating the shape of the contact surface at the point where a real wheel rolls on a real rail, by rotating the outer circumferential surface 1a of the cylindrical rail test piece 1 and the inner circumferential surface 2a of the ring-shaped wheel test piece 2.

[0029] The rotating contact test apparatus 3 shown in Figure 2 is a device that performs tests by rotating the circumferential surface of the rail test piece 1 and the circumferential surface of the wheel test piece 2 using power generated by the power generation unit 5. The rotating contact test apparatus 3 reproduces slippage, which is a state in which a speed difference occurs between the running speed of the vehicle and the peripheral speed of the wheel. The rotating contact test apparatus 3 is a rolling test apparatus that performs tests simulating rolling friction that occurs when a wheel rolls on a rail, wear that occurs between the rail and the wheel when a wheel rolls on a rail, and rolling fatigue such as shelling or creaking cracks that occur due to repeated stress loading when a wheel rolls on a rail. The rotating contact test apparatus 3 is capable of performing rolling tests with slippage, can control the slip ratio with high precision, and can vary the slip ratio steplessly. Here, the slip ratio is the value obtained by dividing the difference between the running speed of the vehicle and the peripheral speed of the wheel by the running speed of the vehicle.The rotary contact test apparatus 3 comprises a frame section 4 shown in Figure 2, a power generation section 5 shown in Figures 2 to 4, bearing sections 6A and 6B shown in Figure 2, a power transmission section 7, rotating shafts 8A and 8B, bearing sections 9A to 9C, a connecting section 10 shown in Figures 2 and 5, a bearing section 11 shown in Figure 2, a torque detection section 12 shown in Figures 2 and 3, a contact position changing section 13 shown in Figures 2 and 5, a rotation detection section 14 shown in Figures 2 and 3, a power transmission section 15 shown in Figure 2, a slip ratio adjustment device 16 shown in Figures 2, 4 and 6, rotating shafts 21A and 21B shown in Figure 2, bearing sections 22A and 22B, a shaft coupling section 23, a power transmission section 24, bearing sections 25A and 25B, rotating shafts 26A and 26B shown in Figures 2, 8 and 11, bearing sections 27A and 27B, and Figures 2, 4 and 5. The device includes a holding section 28 shown in Figures 8, 9, and 11, a shaft coupling section 29 shown in Figures 2, 8, and 11, a rotation detection section 30 shown in Figures 2, 3, 8, 10, and 11, a supply section 31 shown in Figures 2 and 8, a wavy wear suppression section 32 shown in Figures 2 and 10, a load generation section 33 shown in Figures 2, 3, 8, and 9, a contact force fluctuation suppression section 34 shown in Figures 2, 8, and 9, a contact force detection section 35 shown in Figures 2, 3, 8, and 9, a tilt angle changing section 36 shown in Figures 2 and 8 to 11, a test condition setting section 37 shown in Figure 3, a test condition storage section 38, an adjustment rotation speed calculation section 39, a slip ratio calculation section 40, a friction coefficient calculation section 41, a torque-slip ratio relationship storage section 42, a measurement data storage section 43, and a control section 44, among others.

[0030] Unlike conventional two-cylinder rolling contact testing devices that rotate and bring two circular rings into contact, the rotating contact testing device 3 shown in Figure 2 is an inner-outer-circle contact type two-cylinder testing device that rotates and brings into contact an outer ring test piece, the rail test piece 1, and an inner ring test piece, the wheel test piece 2, as shown in Figures 1(A) and 1(B). The rotating contact testing device 3 is a power circulation type testing device that circulates power through a power circulation path R to bring the rail test piece 1 and the wheel test piece 2 into rotational contact, as shown in Figure 4. Here, the power circulation path R is the path through which the power generated by the power generation unit 5 circulates. When the rail test piece 1 rotates due to the driving force generated by the power generation unit 5, and the wheel test piece 2 in contact with the rail test piece 1 rotates due to friction, the power circulation path R returns this frictional force to the driving force generated by the power generation unit 5.

[0031] The frame section 4 shown in Figure 2 is a means for supporting each component that makes up the rotary contact testing apparatus 3. The frame section 4 is configured as a two-tiered frame structure, and includes a linear vertical frame section 4a extending in the vertical direction, a linear upper horizontal frame section 4b extending in the left-right direction and positioned on the upper tier, and a linear lower horizontal frame section 4c extending in the left-right direction and positioned on the lower tier, among others.

[0032] The power generation unit 5 shown in Figures 2 to 4 is a means for generating power to rotate the rail test piece 1 and the wheel test piece 2. The power generation unit 5 is a main motor such as a permanent magnet synchronous motor, which does not require current to create magnetic flux by using permanent magnets in the rotor. As shown in Figure 2, the power generation unit 5 is mounted on the lower horizontal frame section 4c and has a rotating shaft (output shaft) 5a that outputs power to the outside. The power generation unit 5 rotates the rail test piece 1 and the wheel test piece 2 at a constant rotational speed from the start of the test until the end of the test. The bearing sections 6A and 6B shown in Figure 2 are means for rotatably supporting the rotating shaft 5a of the power generation unit 5. The bearing sections 6A and 6B are located on both sides of the pulley 7a of the power transmission section 7 and are mounted on the lower horizontal frame section 4c.

[0033] The power transmission unit 7 shown in Figure 2 is a means for transmitting the power generated by the power generation unit 5 to the rail test piece 1 and the wheel test piece 2. The power transmission unit 7 is a winding transmission device such as a belt drive that transmits rotation between two parallel rotating shafts 5a and 8B. The power transmission unit 7 includes pulleys (belt pulleys) 7a, 7b and a belt 7c. The pulleys 7a and 7b are members on which the belt 7c is placed. The pulley 7a is a driving force that generates the driving force to drive the belt 7c, and rotates together with the rotating shaft 5a with the output shaft (driving shaft) 5a of the power generation unit 5 as the center of rotation. The pulley 7b is a driven pulley driven by the belt 7c, and rotates together with the rotating shaft 8B with the rotating shaft (driven shaft) 8B as the center of rotation. The belt 7c is a member that is wound around the pulleys 7a and 7b. Belt 7c is, for example, a toothed belt (cogged belt) or a timing belt, which is a winding member (winding mediation link) such as a timing belt, in which teeth that mesh with the corrugated grooves formed on the outer circumference of pulleys 7a and 7b are continuously formed in a corrugated shape along the length of the inner circumference.

[0034] The rotating shafts 8A and 8B are components that rotate the rail test piece 1. The rotating shafts 8A and 8B transmit the power generated by the power generation unit 5 to the rail test piece 1. The end of the rotating shaft 8A is attached to the rail test piece 1 such that the centerline of the rotating shaft 8A coincides with the centerline O1 of the rail test piece 1, and it rotates together with the rail test piece 1. The rotating shaft 8B is positioned such that the centerline of the rotating shaft 8B coincides with the centerline of the rotating shaft 8A.

[0035] The bearing portion 9A shown in Figures 2 and 5 is a means for rotatably supporting the rotating shaft 8A. The bearing portion 9A is attached to the connecting portion 13c of the contact position changing portion 13. The bearing portions 9B and 9C shown in Figure 2 are means for rotatably supporting the rotating shaft 8B. The bearing portions 9B and 9C are located on both sides of the pulley 7b of the power transmission portion 7 and the pulley 15a of the power transmission portion 15, and are attached to the upper horizontal frame portion 4b.

[0036] The connecting portion 10 shown in Figures 2 and 5 is a means for connecting the rotating shaft 8A and the torque detection unit 12. As shown in Figure 5, the connecting portion 10 maintains the connection between the rotating shaft 8A and the torque detection unit 12 even when the distance between the rotating shaft 8A and the torque detection unit 12 changes by reciprocating the rail test piece 1 in the direction of the centerlines O1 and O2 relative to the wheel test piece 2 in the contact position changing portion 13. The connecting portion 10 includes a spline shaft 10a having teeth spaced apart in the circumferential direction, an outer cylinder (spline nut) 10b that meshes with the teeth on the spline shaft 10a side and is movable relative to the spline shaft 10a in the longitudinal direction, and steel balls 10c that roll between grooves formed in the longitudinal direction on the outer circumference of the spline shaft 10a and grooves formed in the longitudinal direction on the inner circumference of the outer cylinder 10b. The connecting section 10 is a ball spline or the like that can transmit torque between the spline shaft 10a and the outer cylinder 10b while the spline shaft 10a moves linearly relative to the outer cylinder 10b by causing the steel ball 10c to move in a circular motion. The connecting section 10 rotates together with the rotating shaft 8A and the torque detection section 12. The end of the spline shaft 10a of the connecting section 10 is joined to the end of the rotating shaft 8A via a joint, and the end of the outer cylinder 10b is joined to the end of the torque detection section 12 via a joint. The bearing section 11 shown in Figure 2 is a means for rotatably supporting the connecting section 10. The bearing section 11 is attached to the upper horizontal frame section 4b.

[0037] The torque detection unit 12 shown in Figures 2 and 3 is a means for detecting the torque acting on the rail test piece 1. As shown in Figure 2, the torque detection unit 12 is mounted between the rotating shaft 8B and the connecting part 10, and rotates together with the rotating shaft 8B and the connecting part 10. One end of the torque detection unit 12 is joined to the end of the rotating shaft 8B via a joint, and the other end is joined to the end of the connecting part 10 via a joint. The torque detection unit 12 is, for example, a torque meter that measures the twist of the rotating shaft in accordance with the torque acting on the rotating shaft, while the rotating shaft of the torque detection unit 12, which is connected to the rotating shaft 8B and the connecting part 10, is rotating, and measures this as the torque acting on the rail test piece 1. The torque detection unit 12 outputs the torque acting on the rail test piece 1 as a torque detection signal to the control unit 44.

[0038] The contact position changing section 13 shown in Figures 2 and 5 is a means for changing the contact position P between the circumferential surface of the rail test piece 1 and the circumferential surface of the wheel test piece 2 in the direction of the centerlines O1 and O2 of the rail test piece 1 and the wheel test piece 2. The contact position changing section 13 moves the rail test piece 1 back and forth in the left-right direction (in the direction of the centerlines O1 and O2) relative to the wheel test piece 2, as shown in Figure 5, in order to simulate the serpentine motion (left-right movement) of a real wheel relative to a real rail. The contact position changing section 13 moves the rail test piece 1 backward relative to the wheel test piece 2 when attaching or detaching the rail test piece 1 or the wheel test piece 2. The contact position changing section 13 forms a predetermined gap between the rail test piece 1 and the wheel test piece 2 so that tools used when attaching or detaching the rail test piece 1 or the wheel test piece 2 can be handled. The contact position changing section 13 includes a power generating section 13a, a lead screw mechanism section 13b, and a connecting section 13c, as shown in Figures 2 and 5.

[0039] The power generation unit 13a is a means for generating power to move the rail test piece 1 back and forth. The power generation unit 13a is a servo motor or the like that generates power to rotate the screw shaft 13d of the lead screw mechanism 13b shown in Figure 5 in both forward and reverse directions, and is capable of feedback control of position and speed. The end of the rotating shaft (output shaft) of the power generation unit 13a is joined to the end of the screw shaft 13d of the lead screw mechanism 13b via a joint. The lead screw mechanism 13b is a means for converting the rotational motion of the power generation unit 13a into linear motion. The lead screw mechanism 13b includes a screw shaft 13d having a groove on its outer circumference, a nut 13e having a groove on its inner circumference, and a ball 13f that rolls between the groove on the screw shaft 13d side and the groove on the nut 13e side. The lead screw mechanism 13b is attached to the upper horizontal frame 4b via bearings that rotatably support both ends of the screw shaft 13d. The connecting portion 13c is a means for connecting the bearing portion 9A and the nut 13e. One end of the connecting portion 13c is attached to the bearing portion 9A, and the other end is attached to the nut 13e. The connecting portion 13c moves back and forth together with the rotating shaft 8A, the bearing portion 9A, and the spline shaft 10a, thereby causing the rail test piece 1 to move back and forth.

[0040] The rotation detection unit 14 shown in Figures 2 and 3 is a means for detecting the rotation of the rail test piece 1. As shown in Figure 2, the rotation detection unit 14 is attached to the end of the rotating shaft 8B and detects the rotation speed, peripheral speed, or number of rotations (amount of movement) of the rail test piece 1 by detecting the rotation of the rotating shafts 8A, 8B, the connecting part 10, and the torque detection unit 12. The rotation detection unit 14 is an encoder that measures, for example, the rotation speed, peripheral speed, or number of rotations of the rail test piece 1 from the time it starts rotating until it stops rotating. The rotation detection unit 14 outputs a rotation detection signal corresponding to the rotation of the rail test piece 1 to the control unit 44.

[0041] The power transmission unit 15 shown in Figure 2 is a means for transmitting the power generated by the power generation unit 5 to the rotation speed adjustment unit 20. Similar to the power transmission unit 7, the power transmission unit 15 is equipped with pulleys 15a, 15b and a belt 15c, and transmits rotation between two parallel rotating shafts 8B and 18. The pulley 15a is a driving force that generates the driving force to drive the belt 15c, and rotates together with the rotating shaft (driving shaft) 8B with the rotating shaft 8B as its center of rotation. The pulley 15b is a driven wheel driven by the belt 15c, and rotates together with the rotating shaft (driven shaft) 18 with the rotating shaft 18 as its center of rotation.

[0042] The slip ratio adjustment device 16 shown in Figures 2, 4, and 6 is a device that adjusts the slip ratio between the circumferential surface of the rail test piece 1 and the circumferential surface of the wheel test piece 2, which are in rotational contact with the power generated by the power generation unit 5. The slip ratio adjustment device 16 adjusts the slip ratio so that the circumferential speed of the wheel test piece 2 is greater than the circumferential speed of the rail test piece 1, or so that the circumferential speed of the rail test piece 1 is greater than the circumferential speed of the wheel test piece 2, in order to reproduce the difference in the direction in which the rail experiences slippage. The slip ratio adjustment device 16 generates a stepless slip ratio with high precision by precisely controlling the slip ratio between the circumferential surface of the rail test piece 1 and the circumferential surface of the wheel test piece 2. The slip ratio adjustment device 16 includes an adjustment power generation unit 17 shown in Figures 2 to 4 and 6, rotating shafts 18 and 19 shown in Figures 2, 4, and 6, and a rotation speed adjustment unit 20, etc.

[0043] The adjustment power generation unit 17 shown in Figures 2-4 and 6 is a means for generating adjustment power to adjust the slip ratio between the circumferential surface of the rail test piece 1 and the circumferential surface of the wheel test piece 2. Unlike the conventional wheel test device 103 shown in Figure 14, in which the second electric motor 120 rotates within a rotating frame 104 in a power circulation path R to rotate the test wheel 102, the adjustment power generation unit 17 generates adjustment power outside the power circulation path R. The adjustment power generation unit 17 generates only the power necessary to cause slip between the circumferential surface of the rail test piece 1 and the circumferential surface of the wheel test piece 2. The adjustment power generation unit 17 is a slip adjustment motor such as a servo motor that generates power to rotate the input shaft 20b in the forward and reverse directions and is capable of feedback control of position and speed, as shown in Figures 6 and 7. Unlike the conventional wheel test device 103 shown in Figure 14, the adjustment power generation unit 17 shown in Figures 2 and 6 uses a general-purpose servo motor fixed outside the power circulation path R. The adjustment power generation unit 17 can reproduce differences in the direction in which the rail experiences slippage by changing the slip ratio by changing the rotation speed. The adjustment power generation unit 17 is attached to the lower horizontal frame section 4c and is equipped with a rotating shaft (output shaft) 17a that outputs power to the outside.

[0044] The rotating shaft 18 shown in Figures 2, 4, and 6 is a component that rotates using the power generated by the power generation unit 5. As shown in Figure 6, the rotating shaft 18 is a hollow shaft through which the rotating shaft 19 passes, and it rotates in conjunction with the rotating shafts 8A, 8B, the connecting unit 10, and the torque detection unit 12. As shown in Figure 6, the frame 20a of the rotational speed adjustment unit 20 is joined to one end of the rotating shaft 18 via a joint, and as shown in Figure 2, the pulley 15b of the power transmission unit 15 is attached to the other end. The rotating shaft 19 shown in Figures 2, 4, and 6 is a component that rotates using the power generated by the adjustment power generation unit 17. As shown in Figure 6, the input shaft 20b of the rotational speed adjustment unit 20 is joined to one end of the rotating shaft 19 via a joint, and the rotating shaft 17a of the adjustment power generation unit 17 is joined to the other end via a joint.

[0045] The rotational speed adjustment unit 20 shown in Figures 2, 4, and 6 is a means for continuously adjusting the rotational speed of the wheel test piece 2 by receiving power generated by the power generation unit 5 and adjustment power generated by the adjustment power generation unit 17, and outputting power to set the slip ratio to a predetermined slip ratio. When the adjustment power generation unit 17 changes the adjustment power, the rotational speed adjustment unit 20 changes the rotational speed (circumferential speed) of the wheel test piece 2 relative to the rotational speed (circumferential speed) of the rail test piece 1, causing slippage at the contact position P between the circumferential surface of the rail test piece 1 and the circumferential surface of the wheel test piece 2. As shown in Figure 4, the rotational speed adjustment unit 20 adjusts the slip ratio in the middle of the power circulation path R, creating a slight difference in rotational speed between the pulley 15b and the pulley 24a shown in Figure 2. The rotational speed adjustment unit 20 is a planetary gear device having a structure in which planetary gears rotate on their own axis and revolve around a sun gear, and this planetary gear device continuously adjusts the rotational speed of the wheel test piece 2. The rotational speed adjustment unit 20 shown in Figures 6 and 7 is an internal planetary gear transmission using a trochoidal tooth profile. The rotational speed adjustment unit 20 is a cycloidal transmission, such as a Cyclo Reducer (registered trademark), which can achieve both high efficiency and a large reduction ratio. The rotational speed adjustment unit 20 includes a frame 20a shown in Figures 6 and 7, an input shaft 20b, a curved plate (eccentric planetary gear) 20c shown in Figure 7, and an output shaft 20d shown in Figures 6 and 7.

[0046] The frame 20a shown in Figures 6 and 7 is a component that rotates using the power generated by the power generation unit 5. As shown in Figure 7, the frame 20a has a plurality of outer pins 20e spaced at equal intervals on a circumference centered on the center line O3, and the outer pins 20e are pin gears (sun gears) with arc-shaped teeth and rollers. As shown in Figure 6, the frame 20a is connected to the end of the rotating shaft 18 via a joint, and as shown in Figure 7, it rotates with the center line O3 as the center of rotation.

[0047] The input shaft 20b shown in Figures 6 and 7 is a component that rotates using the power generated by the adjustment power generation unit 17. The input shaft 20b is equipped with an eccentric cam (eccentric body (carrier element)) 20f that rotates around a centerline (eccentric axis) O4 that is offset by an eccentricity e from the centerline O3 as its center of rotation. The curved plate (planetary gear) 20c shown in Figure 7 is a component that rotates while oscillating in accordance with the eccentric motion caused by the rotation of the eccentric cam 20f. The inner circumference of the curved plate 20c is fitted to the outer circumference of the eccentric cam 20f via a bearing, and the outer circumference of the curved plate 20c is equipped with epitrochoidal parallel curve teeth 20g that mesh with the outer pin 20e of the frame 20a. The curved plate 20c is equipped with through holes 20h that penetrate the curved plate 20c at equal intervals on the circumference of a circle centered on the centerline O4.

[0048] The output shaft 20d shown in Figures 6 and 7 is a component that generates power to set the slip ratio to a predetermined slip ratio. As shown in Figure 7, the output shaft 20d has a plurality of inner pins 20i spaced equally apart on a circumference centered on the center line O3, and the inner pins 20i with rollers are fitted with a gap between them and the through holes 20h of the curved plate 20c. The output shaft 20d rotates when the oscillating motion of the curved plate 20c is transmitted to the inner pins 20i. When one or more curved plates 20c rotate by the eccentric cam 20f, the rotation speed adjustment unit 20 controls the rotational motion of the curved plate 20c by extracting the rotational motion of the curved plate 20c from the inner pins 20i fitted into the through holes 20h of the curved plate 20c and outputting it to the output shaft 20d.

[0049] The rotating shafts 21A and 21B shown in Figure 2 are components that rotate due to the power output by the rotational speed adjustment unit 20. As shown in Figure 6, the end of the rotating shaft 21A is joined to the end of the output shaft 20d of the rotational speed adjustment unit 20 via a joint, and rotates together with the output shaft 20d. The rotating shaft 21B rotates together with the rotating shaft 21A and the shaft coupling unit 23.

[0050] The bearing section 22A is a means for rotatably supporting the rotating shaft 18. The bearing section 22A is located between the pulley 15b and the adjustment power generation section 17 and is attached to the lower horizontal frame section 4c. The bearing section 22B is a means for rotatably supporting the rotating shaft 21A. The bearing section 22B is located between the rotation speed adjustment section 20 and the shaft coupling section 23 and is attached to the lower horizontal frame section 4c.

[0051] The shaft coupling section 23 is a means for connecting the rotating shaft 21A and the rotating shaft 21B. The shaft coupling section 23 has high rigidity in the torsional direction and low rigidity in the twisting, stepping, and axial directions, and rotates together with the rotating shafts 21A and 21B to transmit power from the rotating shaft 21A to the rotating shaft 21B. One end of the shaft coupling section 23 is joined to the end of the rotating shaft 21A, and the other end is joined to the other end of the rotating shaft 21B.

[0052] The power transmission unit 24 is a means for transmitting the power generated by the rotational speed adjustment unit 20 to the wheel test piece 2. Similar to the power transmission units 7 and 15, the power transmission unit 24 is equipped with pulleys 24a and 24b and a belt 24c, and transmits rotation between two parallel rotating shafts 21B and 26A. The pulley 24a is a driving force that generates the driving force to drive the belt 24c, and rotates together with the rotating shaft (driving shaft) 21B as its center of rotation. The pulley 24b is a driven wheel driven by the belt 24c, and rotates together with the rotating shaft (driven shaft) 26A as its center of rotation. The bearing units 25A and 25B are means for rotatably supporting the rotating shaft 21B. The bearing units 25A and 25B are located on both sides of the pulley 24a of the power transmission unit 24 and are attached to the lower horizontal frame unit 4c.

[0053] The rotating shafts 26A and 26B are components that rotate the wheel test piece 2. The rotating shafts 26A and 26B rotate by the power output of the rotation speed adjustment unit 20 and transmit this power to the wheel test piece 2. The rotating shafts 26A and 26B rotate in conjunction with the rotating shafts 21A and 21B and the shaft coupling unit 23. The rotating shaft 26B rotates together with the rotating shaft 28A of the holding unit 28, with the center line O2 as the center of rotation. The bearing units 27A and 27B are means for rotatably supporting the rotating shaft 26A. The bearing units 27A and 27B are located on both sides of the pulley 24b of the power transmission unit 24 and are attached to the support unit 36a of the inclination angle changing unit 36.

[0054] The holding portion 28 shown in Figures 2, 4, 5, 8, 9, and 11 is a means for rotatably holding the wheel test piece 2. The holding portion 28 holds the wheel test piece 2 so that it can rotate around the center line O2 as the center of rotation, and also holds the wheel test piece 2 so that it can be attached and detached when replacing the wheel test piece 2. The holding portion 28 includes a rotating portion 28a shown in Figure 8, a support portion 28b shown in Figures 8 and 9, a bearing portion 28c, an elastic support portion 28d, a sliding portion 28e shown in Figure 9, a guide portion 28f, and the like.

[0055] The rotating part 28a is a means that rotates together with the wheel test piece 2. The outer circumference of the wheel test piece 2 is fitted into the inner circumference of the flange portion of the rotating part 28a so that the wheel test piece 2 can be attached to and detached from the rotating part 28a, and it rotates around the center line O2 as the center of rotation. The support part 28b is a means that rotatably supports the rotating part 28a. As shown in Figures 8 and 9, the support part 28b is a small frame-shaped member that surrounds the outer circumference of the rotating part 28a, and is a lightweight structure that is unitized together with the rotating part 28a and the bearing part 28c so that the wheel test piece 2 follows the rotation of the rail test piece 1. The support part 28b is fixed to the upper end of the elastic support part 28d while supporting the rotating part 28a in a rotatable manner. The bearing part 28c is a means that rotatably supports the rotating part 28a with respect to the support part 28b. As shown in Figure 8, the bearing portion 28c is sandwiched between the inner circumference of the support portion 28b and the outer circumference of the rotating portion 28a. The inner ring of the bearing portion 28c is attached to the rotating portion 28a, and the outer ring of the bearing portion 28c is attached to the support portion 28b.

[0056] The elastic support portion 28d shown in Figures 8 and 9 is a means for elastically supporting the support portion 28b on the support portion 36a of the inclination angle changing portion 36. The elastic support portion 28d is an elastic member such as a compression spring that supports the holding portion 28 so as to be movable in the vertical direction relative to the support portion 36a of the inclination angle changing portion 36. The elastic support portion 28d is positioned between the lower surface of the support portion 28b and the upper surface of the support portion 36a of the inclination angle changing portion 36. For example, when the load generating portion 33 removes the vertical load applied to the holding portion 28 in order to attach or detach the rail test piece 1 or the wheel test piece 2, the elastic support portion 28d pushes the holding portion 28 upward, thereby creating a gap between the circumferential surface of the rail test piece 1 and the circumferential surface of the wheel test piece 2.

[0057] The sliding portion 28e shown in Figure 9 is a means that moves vertically in conjunction with the support portion 28b. The sliding portion 28e is movable along the guide portion 28f and is fixed to both sides of the support portion 28b. The guide portion 28f is a means that guides the sliding portion 29e so that it can move freely. The guide portion 28f can change its orientation at the same angle as the holding portion 28 so that it can guide the sliding portion 28e even when the tilt angle changing portion 36 rotates the holding portion 28 around the center line O5 as the rotation center and the orientation of the holding portion 28 changes. The guide portion 28f is attached to the vertical frame portion 4a.

[0058] The shaft coupling portion 29 shown in Figures 2, 8, and 11 is a means for connecting the rotating shaft 26A and the rotating shaft 26B. Similar to the shaft coupling portion 23, the shaft coupling portion 29 has high rigidity in the torsional direction and low rigidity in the twisting, stepping, and axial directions. Even if the center line O2 of the rotating shaft 26A and the center line O2 of the rotating shaft 26B are misaligned due to vertical movement of the holding portion 28 shown in Figure 8, power is transmitted between the rotating shaft 26A and the rotating shaft 26B. The shaft coupling portion 29 rotates together with the rotating shafts 26A and 26B, transmitting power from the rotating shaft 26A to the rotating shaft 26B. One end of the shaft coupling portion 29 is joined to the end of the rotating shaft 26A, and the other end is joined to the other end of the rotating shaft 26B.

[0059] The rotation detection unit 30 shown in Figures 2, 3, 8, 10, and 11 is a means for detecting the rotation of the wheel test piece 2. As shown in Figures 2, 8, 10, and 11, the rotation detection unit 30 is attached to the end of the rotating shaft 26A, and by detecting the rotation of the rotating shafts 26A, 26B, the rotating part 28a, and the shaft coupling part 29 shown in Figures 8 and 11, it detects the rotational speed, peripheral speed, or number of rotations (amount of movement) of the wheel test piece 2. The rotation detection unit 30 is an encoder similar to the rotation detection unit 14, and measures the rotational speed, peripheral speed, or number of rotations of the wheel test piece 2 from the time it starts rotating until it stops rotating. The rotation detection unit 30 outputs a rotation detection signal corresponding to the rotation of the wheel test piece 2 to the control unit 44.

[0060] The supply unit 31 shown in Figures 2 and 8 is a means for supplying a feed material M between the circumferential surface of the rail test piece 1 and the circumferential surface of the wheel test piece 2. The supply unit 31 is, for example, a dripping device for dropping liquid, or a spraying device for spraying powder or granular material. Here, the feed material M is, for example, a liquid such as water or oil, a cohesion enhancer which is a powder or granular material such as ceramic particles or silica sand that improve the adhesion coefficient between the wheel and rail, or a friction mitigating material which is a powder or granular material mainly composed of carbon-based materials that reduce the friction coefficient between the wheel and rail. As shown in Figure 8, the supply unit 31 includes a storage section 31a for containing the feed material M, a discharge section 31b for discharging the feed material M from the storage section 31a towards the gap between the circumferential surface of the rail test piece 1 and the circumferential surface of the wheel test piece 2, a flow path 31c through which the feed material M flows from the storage section 31a to the discharge section 31b, and an on / off valve 31d for opening and closing the flow path 31c.

[0061] The corrugated wear suppression section 32 shown in Figures 2 and 10 is a means of suppressing the occurrence of corrugated wear of a specific wave number on the circumferential surface of the rail test piece 1 and / or wheel test piece 2. Here, corrugated wear refers to the continuous unevenness formed on the rail surface due to wear or plastic deformation at regular intervals as a wheel repeatedly rolls on the rail. Corrugated wear often occurs in sharp curve sections, and in actual rails, corrugated wear occurs in two forms: short-wavelength corrugated wear with a relatively short wavelength of 3 to 8 cm, and long-wavelength corrugated wear with a relatively long wavelength of 8 to 30 cm. The corrugated wear suppression section 32 shown in Figures 2 and 10 suppresses the occurrence of corrugated wear of a specific wave number in the rotating contact testing device 3 while allowing the occurrence of corrugated wear of multiple different wave numbers. The corrugated wear suppression section 32 is a flywheel that is detachably attached to the end of the rotating shaft 21B. In conventional two-cylinder testing machines, the test piece also undergoes corrugated wear depending on the natural frequency of the testing machine, so a detachable flywheel was installed. The wavy wear suppression section 32 has a mounting section 32a that penetrates the wavy wear suppression section 32 at its rotational center and engages with the rotating shaft 21B, thereby mounting it to the rotating shaft 21B. For example, multiple flywheels with the same outer diameter are provided for the wavy wear suppression section 32. By changing the number of wavy wear suppression sections mounted on the rotating shaft 21B while the rotation of the rotating shaft 21B is temporarily stopped during the test, the moment of inertia (polar moment of inertia) around the center line of the rotating shaft 21B is changed, thereby changing the overall natural frequency of the rotating system of the rotating contact test device 3. By changing the natural frequencies of the rail test piece 1 and / or wheel test piece 2, the wavy wear suppression section 32 suppresses the growth of wavy wear of a specific wave number on the circumferential surface of the rail test piece 1 and / or wheel test piece 2.

[0062] The load generating unit 33 shown in Figures 2, 3, 8, and 9 is a means for generating a predetermined load so that a contact force acts at the contact position P between the circumferential surface of the rail test piece 1 and the circumferential surface of the wheel test piece 2. The load generating unit 33 presses the wheel test piece 2 against the rail test piece 1 by displacing the holding unit 28 downward and generating a force to compress the contact force fluctuation suppression unit 34, thereby applying a contact force to the contact position P between the rail test piece 1 and the wheel test piece 2. The load generating unit 33 is, for example, an actuator such as a hydraulic cylinder or a pneumatic cylinder. As shown in Figures 8 and 9, the load generating unit 33 includes a cylinder section 33a through which working fluid flows in and out, a piston section 33b that reciprocates within the cylinder section 33a by this working fluid, and a piston rod section 33c that moves vertically in conjunction with the piston section 33b. In the load generating unit 33, the cylinder section 33a is attached to the vertical frame section 4a. The load generating unit 33 is pre-set to generate a predetermined load before the start of the test, and generates a nearly constant load from the start of the test until the end of the test.

[0063] The contact force fluctuation suppression section 34 shown in Figures 2, 8, and 9 is a means for suppressing fluctuations in the contact force acting on the contact position P. The contact force fluctuation suppression section 34 is positioned between the holding section 28 and the load generating section 33, and the load generated by the load generating section 33 is applied to the contact position P via the holding section 28. The contact force fluctuation suppression section 34 has a suspension function that suppresses fluctuations in the contact force acting on the contact position P by improving the followability of the wheel test piece 2 to the rail test piece 1, for example, when irregularities are formed on the contact surface S between the rail test piece 1 and the wheel test piece 2. The contact force fluctuation suppression section 34 also has a function to suppress the occurrence of wavy wear of a specific wave number on the circumferential surface of the rail test piece 1 and / or the wheel test piece 2, similar to the wavy wear suppression section 32. As shown in Figures 8 and 9, the contact force fluctuation suppression section 34 includes a load receiving section 34a, a support section 34b, an elastic section 34c, and the like.

[0064] The load-receiving portion 34a shown in Figures 8 and 9 is a means for receiving the load generated by the load-generating portion 33. The tip of the piston rod portion 33c of the load-generating portion 33 is in contact with and separated from the upper surface of the load-receiving portion 34a, and the upper end of the elastic portion 34c is in contact with the lower surface of the load-receiving portion 34a. The support portion 34b is a means for supporting the elastic portion 34c. The support portion 34b moves vertically in conjunction with the holding portion 28 while the lower end of the elastic portion 34c is in contact with the upper surface of the support portion 34b. The elastic portion 34c is a means for suppressing fluctuations in contact force by spring action. The elastic portion 34c improves the tracking ability of the wheel test piece 2 relative to the rail test piece 1 by suppressing vertical vibrations that occur when the rail test piece 1 and the wheel test piece 2 make rotational contact. The elastic part 34c is an elastic member such as a compression spring that receives a compressive load from the load generating part 33, and generates a deflection spring force upon receiving the load (compressive load) generated by the load generating part 33. Multiple types of elastic parts 34c with different spring constants are provided in advance. The elastic part 34c is sandwiched between the load receiving part 34a and the support part 34b, and is detachably replaceable between them.

[0065] The contact force fluctuation suppression unit 34 changes the natural frequency of the wheel test piece 2 by changing to an elastic part 34c with a different spring constant while the rotation of the rotating shaft 26B is temporarily stopped during the test. By changing the natural frequencies of the rail test piece 1 and / or the wheel test piece 2, the contact force fluctuation suppression unit 34 suppresses the growth of wavy wear of a specific wave frequency on the circumferential surface of the rail test piece 1 and / or the wheel test piece 2.

[0066] The contact force detection unit 35 shown in Figures 2, 8, and 9 is a means for detecting the contact force acting on the contact position P. The contact force detection unit 35 is positioned between the load generation unit 33 and the contact force fluctuation suppression unit 34, and detects the load acting between them. The contact force detection unit 35 is a load cell that measures the load value from when the rail test piece 1 starts rotating until it stops rotating as the contact force acting on the contact position P. The contact force detection unit 35 outputs a contact force detection signal corresponding to the contact force acting on the contact position P to the control unit 44.

[0067] The inclination angle changing unit 36 ​​shown in Figures 2 and 8 to 11 is a means for changing the inclination angle θ so that the center line O2 of the wheel test piece 2 with respect to the center line O1 of the rail test piece 1 becomes a predetermined inclination angle θ. As shown in Figures 11 and 12, the inclination angle changing unit 36 ​​rotates the wheel test piece 2 with the center line (yaw axis) O5 as the center of rotation, thereby inclining the center line O2 of the wheel test piece 2 with respect to the center line O1 of the rail test piece 1 to a predetermined inclination angle (for example, about 1°) θ, and simulating the attack angle between the wheel and rail. Here, the attack angle is the relative yaw angle between the rail and the wheel, and is the rotation angle around the vertical axis of the wheel. For example, in the case of the outer rail wheel of a vehicle running on a curved section, the direction in which the center line of the rotation axis of the wheel rotates counterclockwise is considered positive for the attack angle. The tilt angle changing section 36 includes a support section 36a shown in Figures 2 and 8 to 10, a bearing section 36b shown in Figures 8 and 9, a sliding section 36c shown in Figures 8 and 10, a guide section 36d, an operating section 36e shown in Figures 2, 8, 10, and 11, and a feed screw mechanism section 36f shown in Figures 10 and 11.

[0068] The support portion 36a shown in Figures 2 and 8 to 10 is a means for supporting the bearing portions 27A, 27B and the retaining portion 28. As shown in Figures 2 and 11, the support portion 36a is a plate-shaped member that can rotate around the center line O5 as the center of rotation while supporting the bearing portions 27A, 27B and the retaining portion 28. The bearing portion 36b shown in Figures 8 and 9 is a means for rotatably supporting the support portion 36a. As shown in Figure 8, the bearing portion 36b rotates the retaining portion 28 around the center line O5 by rotatably supporting the support portion 36a around the center line O5, which is perpendicular to the center line O1 of the rail test piece 1 and the center line O2 of the wheel test piece 2. As shown in Figures 8 and 9, the bearing portion 36b is positioned between the upper horizontal frame portion 4b and the support portion 36a, and is a thrust bearing that rotates the support portion 36a relative to the upper horizontal frame portion 4b. The bearing section 36b includes a fixed section 36g that is fixed to the upper surface of the upper horizontal frame section 4b, and a rotating section 36h that is fixed to the lower surface of the support section 36a and rotatably fitted into the fixed section 36g.

[0069] The sliding portion 36c shown in Figures 8 and 10 is a means that moves in the left-right direction in conjunction with the support portion 36a. The sliding portion 36c is slidable on the guide portion 36d and is attached to the lower surface of the support portion 36a. The guide portion 36d is a means that guides the sliding portion 36c so that it can move freely. As shown in Figure 8, the guide portion 36d causes the sliding portion 36c to slide when the support portion 36a rotates around the center line O5. The guide portion 36d is attached to the upper surface of the upper horizontal frame portion 4b.

[0070] The operating section 36e shown in Figures 2, 8, 10, and 11 is a means operated when rotating the support section 36a. The operating section 36e is a manual handle that is rotated by an operator. The feed screw mechanism 36f shown in Figures 10 and 11 is a means that converts the rotational motion of the operating section 36e into linear motion. The feed screw mechanism 36f includes a screw shaft 36i having a trapezoidal screw male thread on its outer circumference, a block section 36j attached to the end of the support section 36a and having a female thread that meshes with the screw shaft 36i, and a bearing section 36k attached to the upper horizontal frame section 4b that rotatably supports the screw shaft 36i.

[0071] The test condition setting unit 37 shown in Figure 3 is a means for setting various test conditions related to the rotary contact test apparatus 3. The test condition setting unit 37 is, for example, an input device for inputting test conditions. The test condition setting unit 37 sets test conditions such as the diameters of the rail test piece 1 and the wheel test piece 2, the pitch circle diameters of the pulleys 15a and 15b, the number of teeth of the pulleys 24a and 24b, the set slip ratio when testing with a constant slip ratio, the set torque when testing with a constant torque, the rotational speed of the power generation unit 5, the reduction ratio of the rotational speed adjustment unit 20, the period for the contact position changing unit 13 to reciprocate the rail test piece 1, and the load generated by the load generation unit 33, and outputs the set test conditions as a test condition setting signal (test condition data) to the control unit 44. The test condition storage unit 38 is a means for storing the test conditions set by the test condition setting unit 37 as test condition data. The test condition storage unit 38 is a storage device for storing test condition data.

[0072] The adjustment rotation speed calculation unit 39 is a means for calculating the rotation speed of the adjustment power generation unit 17. Based on the rotation speed of the power generation unit 5 detected by the rotation detection unit 14 and the slip ratio set by the test condition setting unit 37, the adjustment rotation speed calculation unit 39 calculates the rotation speed N2 of the adjustment power generation unit 17 using the following equation 1. In addition, the adjustment rotation speed calculation unit 39 calculates the rotation speed N2 of the adjustment power generation unit 17 using the following equation 1, based on the rotation speed of the power generation unit 5 detected by the rotation detection unit 14 and the slip ratio corresponding to the set torque stored in the torque-slip ratio relationship storage unit 42.

[0073]

number

[0074] Here, as shown in Equation 1, D1 is the diameter of the rail test piece 1, D2 is the diameter of the wheel test piece 2, D3 is the pitch circle diameter of pulley 15a, D4 is the pitch circle diameter of pulley 15b, D5 is the pitch circle diameter of pulley 24a, D6 is the pitch circle diameter of pulley 24b, R is the reduction ratio of the rotation speed adjustment unit 20, s is the slip ratio, and N1 is the rotation speed of the power generation unit 5 detected by the rotation detection unit 14. The adjustment rotation speed calculation unit 39 outputs the calculated rotation speed of the adjustment power generation unit 17 as an adjustment rotation speed signal (adjustment rotation speed data) to the control unit 44.

[0075] The slip ratio calculation unit 40 is a means for calculating the slip ratio between the circumferential surface of the rail test piece 1 and the circumferential surface of the wheel test piece 2. The slip ratio calculation unit 40 calculates the slip ratio based on the detection result of the rotation detection unit 14 (circumferential speed of the rail test piece 1) and the detection result of the rotation detection unit 30 (circumferential speed of the wheel test piece 2). The slip ratio calculation unit 40 calculates the slip ratio based on the rotation detection signal output by the rotation detection unit 14 and the rotation detection signal output by the rotation detection unit 30, and outputs this calculation result as a slip ratio signal (slip ratio data) to the control unit 44.

[0076] The friction coefficient calculation unit 41 is a means for calculating the friction coefficient between the circumferential surface of the rail test piece 1 and the circumferential surface of the wheel test piece 2. The friction coefficient calculation unit 41 calculates the friction coefficient based, for example, on the detection result of the torque detection unit 12 (torque acting on the contact position P) and the detection result of the contact force detection unit 35 (contact force acting on the contact position P). The friction coefficient calculation unit 41 removes components such as the spring force due to the elastic part 34c of the contact force fluctuation suppression unit 34 included in the contact force detection signal output by the contact force detection unit 35 through data processing, and calculates the friction coefficient by averaging it over time. The friction coefficient calculation unit 41 calculates the friction coefficient based on the torque detection signal output by the torque detection unit 12 and the contact force detection signal output by the contact force detection unit 35, and outputs this calculation result as a friction coefficient signal (friction coefficient data) to the control unit 44.

[0077] The torque-slip ratio relationship storage unit 42 is a means for storing the relationship between torque and slip ratio. The torque-slip ratio relationship storage unit 42 is a memory device that stores the relationship between the slip ratio and torque between the circumferential surface of the rail test piece 1 and the circumferential surface of the wheel test piece 2, since it is predicted that there is a constant relationship between torque and slip ratio. When the test is performed with a constant set torque, the torque-slip ratio relationship storage unit 42 stores the slip ratio corresponding to this set torque, or the slip ratio corresponding to the difference between the detected torque and the set torque (target torque), etc., as torque-slip ratio relationship data by creating a table or calculation formula. The torque-slip ratio relationship storage unit 42 is used to feedforward control the rotation speed of the adjustment power generation unit 17 so that the slip ratio corresponds to the set torque, or it is used to feedback control the rotation speed of the adjustment power generation unit 17 so that the slip ratio is proportional to the difference between the detected torque and the set torque.

[0078] The measurement data storage unit 43 is a means for storing various measurement data related to the rotary contact testing apparatus 3. The measurement data storage unit 43 is a memory device that, for example, stores slip ratio data calculated by the slip ratio calculation unit 40 in chronological order, and stores friction coefficient data calculated by the friction coefficient calculation unit 41 in chronological order.

[0079] The control unit 44 is a central processing unit (CPU) that controls various operations related to the rotary contact testing device 3. The control unit 44, for example, commands the power generation unit 5 to generate power for rotating the rail test piece 1 and the wheel test piece 2, outputs the torque detection signal output by the torque detection unit 12 to the friction coefficient calculation unit 41, commands the power generation unit 13a to generate power for reciprocating the rail test piece 1, outputs the rotation detection signal output by the rotation detection unit 14 to the adjustment rotation speed calculation unit 39 and the slip ratio calculation unit 40, commands the adjustment power generation unit 17 to generate adjustment power, outputs the rotation detection signal output by the rotation detection unit 30 to the slip ratio calculation unit 40, commands the load generation unit 33 to generate a predetermined load, outputs the contact force detection signal output by the contact force detection unit 35 to the friction coefficient calculation unit 41, outputs the test condition data output by the test condition setting unit 37 to the test condition storage unit 38, commands the test condition storage unit 38 to store the test condition data, and reads the test condition data from the test condition storage unit 38. The system outputs to the adjustment rotation speed calculation unit 39, commands the adjustment rotation speed calculation unit 39 to calculate the adjustment rotation speed, commands the slip rate calculation unit 40 to calculate the slip rate, commands the friction coefficient calculation unit 41 to calculate the friction coefficient, reads torque-slip rate relationship data from the torque-slip rate relationship storage unit 42, outputs the slip rate corresponding to the set torque identified from the torque-slip rate relationship data as slip rate data to the adjustment power generation unit 17, outputs the slip rate corresponding to the difference between the detected torque and the set torque identified from the torque-slip rate relationship data as slip rate data to the adjustment power generation unit 17, controls the rotation speed of the adjustment power generation unit 17 so that the slip rate corresponds to the set torque, controls the rotation speed of the adjustment power generation unit 17 so that the slip rate is proportional to the difference between the detected torque and the set torque, and commands the measurement data storage unit 43 to store the measurement data. The control unit 44 is connected to a power generation unit 5, a torque detection unit 12, a power generation unit 13a, a rotation detection unit 14, an adjustment power generation unit 17, a rotation detection unit 30, a load generation unit 33, a contact force detection unit 35, a test condition setting unit 37, a test condition storage unit 38, an adjustment rotation speed calculation unit 39, a slip ratio calculation unit 40, a friction coefficient calculation unit 41, a torque-slip ratio relationship storage unit 42, and a measurement data storage unit 43.

[0080] Next, the operation of the rotary contact testing apparatus and the slip ratio adjustment apparatus according to the first embodiment of this invention will be described. (Rotational contact test operation) When an operator sets the test conditions by operating the test condition setting unit 37 shown in Figure 3, the rotary contact test device 3 shown in Figure 2 starts operating according to these test conditions, and when the power generation unit 5 rotates the rotary shaft 5a, the rotary shafts 8A and 8B rotate via the power transmission unit 7. As a result, the power generated by the power generation unit 5 is transmitted to the rail test piece 1, causing the rail test piece 1 to rotate, and the wheel test piece 2 that contacts the rail test piece 1 also rotates. When the rotary shafts 8A and 8B shown in Figure 2 rotate, the rotary shaft 18 rotates via the power transmission unit 15, and the power generated by the power generation unit 5 is transmitted to the rotation speed adjustment unit 20, causing the frame 20a of the rotation speed adjustment unit 20 shown in Figures 6 and 7 to rotate.

[0081] The control unit 44 reads the test conditions from the test condition storage unit 38 shown in Figure 3 and outputs these test conditions to the adjustment rotation speed calculation unit 39 shown in Figure 2. In addition, the rotation detection unit 14 shown in Figures 2 and 3 detects the rotation speed N1 of the power generation unit 5 and outputs a rotation detection signal corresponding to this rotation speed N1 to the control unit 44. The adjustment rotation speed calculation unit 39 calculates the rotation speed N2 of the adjustment power generation unit 17 using Equation 1 based on these test conditions and the rotation speed N1 of the power generation unit 5, and when the adjustment rotation speed calculation unit 39 outputs the adjustment rotation speed signal to the control unit 44, the control unit 44 drives and controls the adjustment power generation unit 17 so that it rotates at rotation speed N2. As a result, the rotating shafts 17a and 19 of the adjustment power generation unit 17 rotate at a rotational speed N2, and the adjustment power generated by the adjustment power generation unit 17 is transmitted to the rotational speed adjustment unit 20, causing the input shaft 20b of the rotational speed adjustment unit 20 shown in Figure 6 to rotate.

[0082] When power is input from the power generation unit 5 shown in Figure 2 to the rotation speed adjustment unit 20, and adjustment power is input from the adjustment power generation unit 17 to the rotation speed adjustment unit 20, the output shaft 20d of the rotation speed adjustment unit 20 shown in Figure 6 rotates, and the rotation shafts 21A and 21B shown in Figure 2 also rotate. When the rotation shafts 21A and 21B rotate, the rotation shafts 26A and 26B rotate via the power transmission unit 24, and the power generated by the rotation speed adjustment unit 20 is transmitted to the wheel test piece 2, causing the wheel test piece 2 to rotate. The rotation speed adjustment unit 20 generates power so that the slip ratio is set by the test condition setting unit 37, and the slip ratio between the circumferential surface of the rail test piece 1 and the circumferential surface of the wheel test piece 2 is adjusted to a predetermined slip ratio by the power generated by the rotation speed adjustment unit 20.

[0083] When the rotation detection unit 14 shown in Figure 2 detects the rotational speed of the rail test piece 1 and the rotation detection unit 30 detects the rotational speed of the wheel test piece 2, the rotation detection units 14 and 30 shown in Figure 3 output a rotation detection signal to the control unit 44. When the control unit 44 outputs the rotation detection signal to the slip ratio calculation unit 40, the slip ratio calculation unit 40 shown in Figure 3 calculates the slip ratio based on the rotation detection signals output by the rotation detection units 14 and 30. As a result, the slip ratio calculation unit 40 outputs a slip ratio signal to the control unit 44, and when the control unit 44 outputs the slip ratio signal to the measurement data storage unit 43, the time change of the slip ratio is stored in the measurement data storage unit 43.

[0084] When the torque detection unit 12 shown in Figure 2 detects the torque at the contact position P, and the contact force detection unit 35 detects the load acting on the contact position P, the torque detection unit 12 shown in Figure 3 outputs a torque detection signal to the control unit 44, and the contact force detection unit 35 outputs a contact force detection signal to the control unit 44. When the control unit 44 outputs the torque detection signal and the contact force detection signal to the friction coefficient calculation unit 41, the friction coefficient calculation unit 41 shown in Figure 3 calculates the friction coefficient based on the torque detection signal output by the torque detection unit 12 and the contact force detection signal output by the contact force detection unit 35. As a result, the friction coefficient calculation unit 41 outputs a friction coefficient signal to the control unit 44, and when the control unit 44 outputs the friction coefficient signal to the measurement data storage unit 43, the time change of the friction coefficient is stored in the measurement data storage unit 43.

[0085] (Test operation to keep the slip ratio constant) When measuring the coefficient of friction with a constant slip ratio, the adjustment rotation speed calculation unit 39, shown in Figure 3, calculates the rotation speed N2 of the adjustment power generation unit 17 using Equation 1, based on the set slip ratio set by the test condition setting unit 37 shown in Figure 3 and the rotation speed N1 of the power generation unit 5 detected by the rotation detection unit 14 shown in Figures 2 and 3. When the adjustment rotation speed calculation unit 39 outputs the adjustment rotation speed signal to the control unit 44, the control unit 44 drives and controls the adjustment power generation unit 17 so that it rotates at rotation speed N2 and maintains a constant set slip ratio. As a result, even if the rotation speed N1 of the power generation unit 5 fluctuates, the adjustment power generation unit 17 is controlled by the control unit 44 so that the slip ratio remains constant, and the friction coefficient calculation unit 41 calculates the coefficient of friction when the test is conducted with a constant slip ratio, and the time change of the coefficient of friction is stored in the measurement data storage unit 43.

[0086] (Test operation to maintain constant torque) When measuring the slip ratio while keeping the torque constant, the control unit 44 reads torque-slip ratio relationship data from the torque-slip ratio relationship storage unit 42 shown in Figure 3, and drives the adjustment power generation unit 17 using feedforward control and / or feedback control. In the case of feedforward control, the control unit 44 identifies the slip ratio corresponding to the set torque stored in the test condition storage unit 38 from the torque-slip ratio relationship data. In the case of feedback control, the control unit 44 identifies the slip ratio corresponding to the difference between the detected torque (actually generated torque) detected by the torque detection unit 12 and the set torque (target torque) stored in the test condition storage unit 38 from the torque-slip ratio relationship data. Based on the slip ratio identified by the control unit 44 and the rotational speed N1 of the power generation unit 5 detected by the rotation detection unit 14 shown in Figures 2 and 3, the adjustment rotational speed calculation unit 39 calculates the rotational speed N2 of the adjustment power generation unit 17 using Equation 1. When the adjustment rotation speed calculation unit 39 outputs an adjustment rotation speed signal to the control unit 44, the control unit 44 drives and controls the adjustment power generation unit 17 so that it rotates at rotation speed N2 and maintains a constant slip ratio. Generally, the higher the slip ratio, the greater the generated torque. Therefore, in the case of feedback control, when the torque is excessive, the control unit 44 controls the adjustment power generation unit 17 so that the slip ratio decreases, and when the torque is insufficient, the control unit 44 controls the adjustment power generation unit 17 so that the slip ratio increases. As a result, even if the rotation speed N1 of the power generation unit 5 fluctuates, the adjustment power generation unit 17 is controlled by the control unit 44 so that the torque remains constant. The slip ratio calculation unit 40 calculates the slip ratio when the torque is kept constant during testing, and the time change of the slip ratio is stored in the measurement data storage unit 43.

[0087] (Contact position change operation) As shown in Figure 5, when the contact position P is changed by the contact position changing unit 13, the control unit 44 reads the reciprocating motion period of the rail test piece 1 set by the test condition setting unit 37 shown in Figure 3 from the test condition storage unit 38. When the control unit 44 commands the power generation unit 13a to perform the reciprocating motion of the rail test piece 1, the power generation unit 13a repeatedly rotates the screw shaft 13d of the lead screw mechanism unit 13b shown in Figure 5 in forward and reverse directions at a predetermined period, and the bearing unit 9A moves back and forth together with the connecting unit 13c and nut 13e. As a result, the rail test piece 1 moves back and forth relative to the wheel test piece 2 while the rail test piece 1 and the wheel test piece 2 are in rotational contact, and the contact position P changes. At this time, the distance between the rotating shaft 8B and torque detection unit 12 shown in Figure 2 and the rotating shaft 8A changes, but power is transmitted between them because the connecting unit 10 shown in Figure 5 is expandable and retractable and maintains the connected state.

[0088] (Tilting angle change operation) As shown in Figure 12, when tilting the center line O2 of the wheel test piece 2 by an inclination angle θ with respect to the center line O1 of the rail test piece 1, the operator rotates the operating part 36e of the inclination angle changing part 36 shown in Figures 10 and 11. As a result, the male thread portion of the screw shaft 36i of the feed screw mechanism 36f rotates while engaging with the female thread portion of the block part 36j, causing the support part 36a to rotate around the center line O5 shown in Figures 8, 9 and 11, and the support part 36a to move horizontally in a pseudo-linear manner as shown in Figure 11. The distance from the center line O5 to the block part 36j is long, and there is a mechanical gap (backlash) between the male thread portion of the screw shaft 36i and the female thread portion of the block part 36j. For this reason, even though the block part 36j shown in Figures 10 and 11 is fixed to the support part 36a, the support part 36a can rotate by a small inclination angle θ as shown in Figure 11. As shown in Figure 11(B), when the support part 36a rotates, the pulley 24a of the power transmission part 24 also rotates, but the belt 24c twists slightly, so the belt 24c does not hinder the transmission of power from the rotating shaft 21B to the rotating shaft 26A. When the bearing parts 27A, 27B, the holding part 28 and the shaft coupling part 29 rotate together with the support part 36a around the center line O5, as shown in Figure 12, the center line O2 of the wheel test piece 2 rotates by an inclination angle θ with respect to the center line O1 of the rail test piece 1, reproducing the same situation as the attack angle between the wheel and rail.

[0089] [Table 1]

[0090] Table 1 shows an example of calculations when adjusting the slip ratio using the rotary contact testing apparatus according to the first embodiment of this invention. Table 1 shows an example of calculations when the outer diameter D1 of the rail test piece 1 is 0.06 (m), the inner diameter D2 of the wheel test piece 2 is 0.07 (m), and the gear ratio r of the rotation speed adjustment unit 20 is 119. As shown in Table 1, the slip ratio s can be adjusted to any slip ratio by adjusting the rotation speed N1 of the wheel test piece 2 with the rotation speed adjustment unit 20, and the test can be performed by reproducing the difference in the direction in which the rail experiences slippage.

[0091] The rotary contact testing apparatus according to the first embodiment of this invention has the following effects. (1) In this first embodiment, outside the power circulation path R through which the power generated by the power generation unit 5 circulates, the adjustment power generation unit 17 generates adjustment power to adjust the slip ratio between the circumferential surface of the rail test piece 1 and the circumferential surface of the wheel test piece 2. In addition, in this first embodiment, the rotation speed adjustment unit 20 continuously adjusts the rotation speed of the wheel test piece 2 by receiving the power generated by the power generation unit 5 and the adjustment power generated by the adjustment power generation unit 17 as input and outputting power to set the slip ratio to a predetermined slip ratio. Therefore, by controlling the slip ratio with high precision, the slip ratio can be varied continuously. Furthermore, the rolling contact state over a wide range of slip ratios can be reproduced with high precision, and changes such as surface roughness and plastic deformation of the rail test piece 1 and the wheel test piece 2 can be reproduced with high precision. Furthermore, material properties such as contact force (adhesion) characteristics, wear characteristics, or rolling fatigue characteristics of the rail test piece 1 and the wheel test piece 2 that are in rolling contact can be evaluated, and various properties such as lubricants used between them can be evaluated. Furthermore, unlike the conventional wheel testing device 103, in which the second motor 120 rotates within the rotating frame 104 in the power circulation path R while rotating the test wheel 102, the adjustment power generation unit 17 is fixed outside the power circulation path R and generates adjustment power. Therefore, it is not necessary to use a complex structure and a relatively high-output, expensive motor like the conventional wheel testing device 103, and a simple structure can be used, and a relatively low-output, inexpensive, general-purpose servo motor can be used. In addition, only the power necessary to create slip between the circumferential surface of the rail test piece 1 and the circumferential surface of the wheel test piece 2 can be generated from the adjustment power generation unit 17. Moreover, compared to the conventional wheel testing device 103, in which the second motor 120 within the rotating frame 104 is rotated by the first motor 105 together with the rotating frame 104, it is possible to generate a relatively large frictional force with a relatively low-output motor and perform the test.

[0092] (2) In this first embodiment, the rotation speed adjustment unit 20 is a planetary gear transmission that continuously adjusts the rotation speed of the wheel test piece 2. Therefore, the rotation speed of the wheel test piece 2 can be easily reduced or increased, and the slip ratio between the circumferential surface of the rail test piece 1 and the circumferential surface of the wheel test piece 2 can be easily adjusted.

[0093] (3) In this first embodiment, the rotational speed adjustment unit 20 is an internal planetary gear transmission using a trochoidal tooth profile. Therefore, by inserting an internal planetary gear transmission, such as a cycloidal transmission capable of finely adjusting the rotational speed, into the power circulation path R as a mechanism for circulating braking force back into driving force, the slip ratio can be adjusted with high precision in a stepless manner.

[0094] (4) In this first embodiment, the contact position P between the circumferential surface of the rail test piece 1 and the circumferential surface of the wheel test piece 2 is changed by the contact position changing section 13 in the direction of the centerlines O1 and O2 of the rail test piece 1 and the wheel test piece 2. Therefore, the same situation as when a real wheel serpentines from side to side relative to a real rail can be reproduced between the rail test piece 1 and the wheel test piece 2, and the test can be carried out.

[0095] (5) In this first embodiment, the supply unit 31 supplies the supply material M between the circumferential surface of the rail test piece 1 and the circumferential surface of the wheel test piece 2. Therefore, the effect of the supply material M, such as water, adhesion enhancer, or friction reducer, which is supplied between a real rail and a real wheel, can be confirmed by supplying it between the rail test piece 1 and the wheel test piece 2.

[0096] (6) In this first embodiment, the wavy wear suppression unit 32 suppresses the occurrence of wavy wear of a specific wave frequency on the circumferential surface of the rail test piece 1 and / or wheel test piece 2. Therefore, by changing the overall natural frequency of the rotation system of the rotational contact test device 3, the wave frequency of the wavy wear can be changed, thereby suppressing the occurrence of wavy wear of a specific wave frequency. For example, in a conventional two-cylinder rolling test device, since the two cylinders rotate while in contact for a long time, wavy wear with a wavelength of several mm tends to occur on the surface of the test piece, and it is believed that the cause of the occurrence of wavy wear is the natural frequency around the axis due to the moment of inertia. In this first embodiment, in order to suppress the growth of wavy wear of a specific wave frequency, multiple wavy wear of different wave frequencies can be generated. Therefore, since wear of various wavelengths occurs, the occurrence of wavy wear of a specific wave frequency can be suppressed as a result, the rail test piece 1 and / or wheel test piece 2 can maintain a shape close to a cylinder, and it is possible to prevent the growth of wavy wear of a specific wave frequency that would make it difficult to continue the test.

[0097] (7) In this first embodiment, the load generating unit 33 generates a predetermined load so that a contact force acts at the contact position P between the circumferential surface of the rail test piece 1 and the circumferential surface of the wheel test piece 2. Therefore, by applying a force to the contact position P between the rail test piece 1 and the wheel test piece 2, it is possible to perform a test that simulates the wheel load acting between the wheel and the rail.

[0098] (8) In this first embodiment, the contact force fluctuation suppression unit 34 suppresses fluctuations in the contact force acting on the contact position P. Therefore, even if irregularities are formed on the circumferential surfaces of the rail test piece 1 and the wheel test piece 2 that are in rotational contact, the ability to follow these circumferential surfaces can be improved, and they can be rotated smoothly. For example, the ability to follow the contact surface S can be improved by a pressing mechanism that combines a hydraulic or pneumatic load generating unit 33 and a spring mechanism contact force fluctuation suppression unit 34. As a result, a stable and continuous contact force can be applied to the contact position P, allowing the test to be continued for a long period of time with reduced fluctuations in the contact force, and enabling the acquisition of highly accurate test results with minimal influence from fluctuations in the contact force.

[0099] (9) In this first embodiment, the contact force fluctuation suppression unit 34 is equipped with multiple types of elastic parts 34c with different spring constants, and the elastic parts 34c are detachable and replaceable. Therefore, by changing the natural frequency of the wheel test piece 2, the wave number of the wavy wear can be changed, and the occurrence of wavy wear of a specific wave number can be suppressed.

[0100] (10) In this first embodiment, the inclination angle changing unit 36 ​​changes the inclination angle θ so that the center line O2 of the wheel test piece 2 with respect to the center line O1 of the rail test piece 1 becomes a predetermined inclination angle θ. As a result, the contact angle of the wheel test piece 2 with respect to the rail test piece 1 can be changed to make rotational contact, and a test simulating the attack angle between the wheel and rail can be performed.

[0101] (11) In this first embodiment, the rail test piece 1 is a cylindrical test piece that simulates an actual rail, and the wheel test piece 2 is a ring-shaped test piece that simulates an actual wheel and rotates in contact with the inner circumference of the rail test piece 1. For example, when the outer circumference of the ring-shaped rail test piece and the outer circumference of the ring-shaped wheel test piece are brought into rotational contact, as in a conventional two-cylinder rolling test device, the shape of the contact surface S of these test pieces differs from the circular shape of the contact surface between an actual rail and an actual wheel, becoming an elongated ellipse. In this first embodiment, the shape of the contact surface S between the circumferential surface of the rail test piece 1 and the circumferential surface of the wheel test piece 2 can be made to be a substantially circular shape, the same as the shape of the contact surface between an actual rail and an actual wheel, by scaling down the shape of the contact surface. As a result, it is possible to reproduce a situation close to when an actual wheel rolls on an actual rail. Furthermore, it is possible to evaluate material properties such as contact force (adhesion) characteristics, wear characteristics, or rolling fatigue characteristics between the rail test piece 1 and the wheel test piece 2 that are in rolling contact, as well as various performance aspects of lubricants used between the rail test piece 1 and the wheel test piece 2.

[0102] (Second Embodiment) In the following, parts identical to those shown in Figures 1 to 12 are denoted by the same reference numerals, and detailed explanations are omitted. The rotational speed adjustment unit 20 shown in Figure 13 is a harmonic drive gear that utilizes the differential generated by the meshing of a circular internal gear 20k and an elliptical external gear 20m, and this harmonic drive gear gear allows for stepless adjustment of the rotational speed of the wheel test piece 2. The rotational speed adjustment unit 20 is a harmonic differential gear, such as a Harmonic Drive (registered trademark), which has a large reduction ratio, low backlash, is lightweight and compact. The rotational speed adjustment unit 20 includes an internal gear 20k, an external gear 20m, a cam section 20n, and the like.

[0103] The internal gear 20k is a component that rotates using the power generated by the power generation unit 5. The internal gear 20k is connected to the end of the rotating shaft 18 shown in Figure 6 via a coupling and rotates around the center line O3 as the center of rotation. The internal gear 20k has two more teeth than the external gear 20m, with teeth 20p on its inner circumference. It is a rigid, cylindrical component and is a circular spline (C / S) equivalent to the sun gear of a planetary gear system.

[0104] The external gear 20m is a component that generates power to achieve a predetermined slip ratio. The output shaft end of the external gear 20m is joined to the end of the rotating shaft 21A shown in Figure 6 via a joint, and rotates together with the rotating shaft 21A. As shown in Figure 13, the external gear 20m has teeth 20q on its outer circumference and is a thin-walled, cup-shaped metallic elastic component, which is a flexspline (F / S) equivalent to the planetary gears of a planetary gear system. The external gear 20m rotates while elastically deforming in an elliptical shape, so that the long shaft portion 20r meshes with the teeth 20p of the internal gear 20k, and the short shaft portion 20s separates from the teeth of the internal gear 20k.

[0105] The cam portion 20n is a component that rotates due to the adjustment power generated by the adjustment power 17 and makes rotational contact with the inner circumference of the external gear 20m. The cam portion 20n is an elliptical component that elastically deforms the external gear 20m into an elliptical shape, and the outer circumference of this cam portion 20n is fitted to the inner circumference of the external gear 20m via a thin-walled, elastically deformable bearing portion. The cam portion 20n is a wave generator (W / G) corresponding to the carrier of the planetary gear system. The end of the input shaft of the cam portion 20n is joined to the end of the rotating shaft 19 shown in Figure 6 via a coupling portion, and rotates together with the rotating shaft 19.

[0106] Next, the operation of the rotary contact testing apparatus according to the second embodiment of this invention will be described. The internal gear 20k shown in Figure 13 rotates due to the power generated by the power generation unit 5 shown in Figure 2, and the cam unit 20n shown in Figure 13 rotates due to the adjustment power generated by the adjustment power generation unit 17 shown in Figure 2. When the cam unit 20n rotates and the external gear 20m bends in an elliptical shape, the long shaft portion 20r of the external gear 20m meshes with the teeth of the internal gear 20k, and the short shaft portion 20s of the external gear 20m disengages from the teeth of the internal gear 20k, causing the meshing position between the internal gear 20k and the external gear 20m to move sequentially. As a result, while the cam unit 20n rotates once, the external gear 20m rotates in the opposite direction to the cam unit 20n by a difference of two teeth, and the slip ratio between the circumferential surface of the rail test piece 1 and the circumferential surface of the wheel test piece 2 shown in Figure 2 is adjusted. The second embodiment of this invention has the same effects as the first embodiment.

[0107] (Other embodiments) This invention is not limited to the embodiments described above, and various modifications or changes are possible as described below, and these also fall within the scope of this invention. (1) In this embodiment, the case in which the rail test piece 1 is a cylindrical rotating body and the wheel test piece 2 is a ring-shaped rotating body has been described as an example. However, the present invention can also be applied to cases in which the rail test piece 1 is a ring-shaped rotating body and the wheel test piece 2 is a cylindrical rotating body, or in cases in which both the rail test piece 1 and the wheel test piece 2 are cylindrical rotating bodies. Furthermore, in this embodiment, the case in which the slip ratio adjustment device 16 is applied to the rotary contact test device 3 has been described as an example. However, the present invention can also be applied to cylindrical grinding machines that process workpieces by adjusting the slip ratio between the circumferential surface of the rotating body of a grinding wheel that is in rotational contact with the circumferential surface of the rotating body of a workpiece, or to rolling mills that roll workpieces by adjusting the slip ratio between a pair of rolling rollers that are in rotational contact. Furthermore, although this embodiment describes the power circulation path R when the wheel test piece 2 rotates due to frictional force as an example, this invention can also be applied when the rail test piece 1 rotates due to frictional force. In this case, the power circulation path is in the opposite direction to the power circulation path R, and the driving force generated by the power generation unit 5 rotates the wheel test piece 2, causing the rail test piece 1 in contact with the wheel test piece 2 to rotate due to frictional force, and this frictional force returns to the driving force generated by the power generation unit 5.

[0108] (2) In this embodiment, the case in which the rotational speed adjustment unit 20 is an internal planetary gear transmission or a harmonic drive gear using a trochoidal tooth profile has been described as an example, but the present invention can also be applied to cases in which the rotational speed adjustment unit 20 is a planetary gear gear of other structures. Furthermore, in this embodiment, the case in which the wavy wear suppression unit 32 is detachably mounted on the rotating shaft 21B has been described as an example, but the present invention can also be applied to cases in which the wavy wear suppression unit 32 is detachably mounted on the rotating shafts 26A and 26B that are closer to the wheel test piece 2, or to cases in which the wavy wear suppression unit 32 is detachably mounted on the rotating shafts 8A and 8B that are closer to the rail test piece 1.

[0109] (3) In this embodiment, the case in which the tilt angle changing unit 36 ​​changes the tilt angle θ by manual operation was used as an example, but the present invention can also be applied to the case in which the tilt angle changing unit 36 ​​changes the tilt angle θ automatically. Also, in this embodiment, the case in which the support unit 36a is rotated by the lead screw mechanism 36f of the tilt angle changing unit 36 ​​was used as an example, but the present invention can also be applied to the case in which the support unit 36a is rotated by a rack / pinion mechanism. Furthermore, in this embodiment, the case in which the block unit 36j is fixed to the support unit 36a of the tilt angle changing unit 36 ​​was used as an example, but the present invention can also be applied to the case in which the block unit 36j is rotatably attached to the support unit 36a. [Explanation of Symbols]

[0110] 1. Rail test piece (first rotating body) 2. Wheel test piece (second rotating body) 3. Rotational Contact Testing Device 4 Frame section 5 Power generation unit 6A,6B Bearing part 7 Power transmission section 7a, 7b Pulley 7c belt 8A, 8B Rotation axis 9A~9C Bearing part 10 Connection part 11 Bearing section 12 Torque detection unit 13 Contact position changing section 14. Rotation detection unit 15 Power transmission section 15a, 15b pulleys 15cm belt 16. Slip ratio adjustment device 17 Adjustment power generation unit 18,19 Rotation axis 20 Rotation speed adjustment section 21A, 21B Rotation shaft 22A,22B Bearing part 23 Shaft coupling section 24 Power transmission section 24a, 24b pulleys 24c belt 25A,25B Bearing part 26A, 26B Rotating shaft 27A,27B Bearing part 28 Holding part 29 Shaft coupling section 30 Rotation detection unit 31 Supply section 32 Wavy wear suppression section 33 Load generation section 34 Contact force fluctuation suppression unit 34c elastic part 35 Contact force detection unit 36. Section for changing the tilt angle 37 Test Condition Setting Unit 38 Test condition storage unit 39 Adjustment rotation speed calculation unit 40. Slip ratio calculation unit 41 Friction coefficient calculation unit 42 Torque-Slip Ratio Relationship Memory Unit 43 Measurement data storage unit 44 Control Unit P Contact position S contact surface R Power circulation path θ Tilt angle O1~O5 center line

Claims

1. A rotational contact testing apparatus that performs a test by rotating and bringing into contact the circumferential surface of a first rotating body and the circumferential surface of a second rotating body using power generated by a power generation unit, Outside the power circulation path through which the power generated by the power generating unit circulates, there is an adjustment power generating unit that generates adjustment power to adjust the slip ratio between the circumferential surface of the first rotating body and the circumferential surface of the second rotating body, A rotation speed adjustment unit receives the power generated by the power generation unit and the adjustment power generated by the adjustment power generation unit, and outputs power to set the slip ratio to a predetermined slip ratio, thereby continuously adjusting the rotation speed of the second rotating body. A rotary contact testing apparatus equipped with the following features.

2. In the rotary contact testing apparatus according to claim 1, The rotational speed adjustment unit is a planetary gear transmission that continuously adjusts the rotational speed of the second rotating body. A rotary contact testing device characterized by the following.

3. In the rotary contact testing apparatus according to claim 1, The rotational speed adjustment unit is an internal planetary gear transmission using a trochoidal tooth profile. A rotary contact testing device characterized by the following.

4. In the rotary contact testing apparatus according to claim 1, The aforementioned rotational speed adjustment unit is a harmonic drive gear device that utilizes the differential reaction caused by the meshing of a circular internal gear and an elliptical external gear. A rotary contact testing device characterized by the following.

5. In the rotary contact testing apparatus according to claim 1, The device includes a contact position changing unit that changes the contact position between the circumferential surface of the first rotating body and the circumferential surface of the second rotating body in the direction of the centerlines of the first and second rotating bodies. A rotary contact testing device characterized by the following.

6. In the rotary contact testing apparatus according to claim 1, The device includes a supply unit that supplies a feed material between the circumferential surface of the first rotating body and the circumferential surface of the second rotating body. A rotary contact testing device characterized by the following.

7. In the rotary contact testing apparatus according to claim 1, The first and / or second rotating body is provided with a wavy wear suppression section that suppresses the occurrence of wavy wear of a specific wave number on the circumferential surface of the first and / or second rotating body. A rotary contact testing device characterized by the following.

8. In the rotary contact testing apparatus according to claim 1, The device is equipped with a load generating unit that generates a predetermined load such that a contact force acts at the contact point between the circumferential surface of the first rotating body and the circumferential surface of the second rotating body. A rotary contact testing device characterized by the following.

9. In the rotary contact testing apparatus according to claim 8, The system includes a contact force fluctuation suppression unit that suppresses fluctuations in the contact force acting at the aforementioned contact position. A rotary contact testing device characterized by the following.

10. In the rotary contact testing apparatus according to claim 9, The contact force fluctuation suppression unit is equipped with multiple types of elastic parts with different spring constants, and these elastic parts are detachable and replaceable. A rotary contact testing device characterized by the following.

11. In the rotary contact testing apparatus according to claim 1, The device includes an inclination angle changing unit that changes the inclination angle such that the center line of the second rotating body is at a predetermined inclination angle with respect to the center line of the first rotating body. A rotary contact testing device characterized by the following.

12. In the rotary contact testing apparatus according to claim 1, The first rotating body is a cylindrical rail test piece that simulates an actual rail, The second rotating body rotates in contact with the outer circumference of the rail test piece and is a circular wheel test piece that simulates a real wheel. A rotary contact testing device characterized by the following.

13. A slip ratio adjustment device for adjusting the slip ratio between the circumferential surface of a first rotating body and the circumferential surface of a second rotating body, which are in rotational contact by the power generated by a power generation unit, Outside the power circulation path through which the power generated by the power generating unit circulates, there is an adjustment power generating unit that generates adjustment power for adjusting the slip ratio, A rotation speed adjustment unit receives the power generated by the power generation unit and the adjustment power generated by the adjustment power generation unit, and outputs power to set the slip ratio to a predetermined slip ratio, thereby continuously adjusting the rotation speed of the second rotating body. A slip ratio adjustment device equipped with the following.

Images