JP2006153610A - Method and instrument for measuring friction evaluation quantity - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a measuring instrument which enables measurement of friction evaluation quantity in a minute slip state, with respect to the wheel tread or the like of a railroad vehicle, and to provide a measuring method using it. <P>SOLUTION: This friction evaluation quantity measuring instrument 1 is constituted so as to measure the coefficient of friction or the like, while tumbling a slip roller 60 in a desired slip factor S in a state that the slip roller 60 is pressed by desired pressing force by using a pressing force setting mechanism 71 on the wheel tread Cs of a wheel C. The slip roller 60 is moved at a moving speed Vf by a moving mechanism 91, while being rotated at a rotary peripheral velocity Vr by a rotating mechanism 61 and, by properly setting Vr and Vf(Vr≠Vf), the slip factor S=(Vr-Vf)/[(Vr+Vf)/2] can be set to an arbitrary minute state. Accordingly, in addition to a perfect slip state capable of being measured by a conventional apparatus, the coefficient of friction or the like in minute slip state (slip factor of about -10% to +10%) can be measured. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an apparatus and a method for measuring a friction evaluation amount (creep force, creep coefficient) of a tread of a railway wheel or the like.

  As a device for measuring the dynamic friction coefficient of railway wheels and rails, for example, “μ Tester” manufactured by Railway Technical Research Institute is known. This μ tester is provided with a slip roller that rotates while sliding in contact with the surface of a wheel or rail, and is a device that measures the characteristics (dynamic friction coefficient) of the friction force acting between the slip roller and the wheel or rail. . The μ tester can be used in various positions at various positions on wheels or rails in the field, and is currently widely used.

  By the way, this μ tester can measure a dynamic friction coefficient of a wheel or a rail, but cannot measure a friction evaluation amount such as a creep coefficient. On the other hand, the present applicant proposes a “creep force measuring device” capable of measuring the relationship between the slip ratio and the creep force (creep saturation characteristic) in Patent Document 1 (Japanese Patent Application No. 2003-399122). did. According to this creep force measuring apparatus, it is possible to easily measure the creep force saturation characteristic on the actual rail by rolling the measuring roller (slip roller) on the rail while pressing it.

Japanese Patent Application No. 2003-399122

  However, rolling with a slight slip (slip rate of about −10% to + 10%) occurs between the actual wheel and the rail. There is a need for an apparatus capable of measuring the friction evaluation amount in this microslip state.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an apparatus and a method capable of measuring a friction evaluation amount in a minute slip state on a tread of a railway vehicle or the like.

  The friction evaluation amount measuring device of the present invention includes a slip roller pressed against the surface of the object to be measured, a rotating unit that rotates the slip roller on the surface of the object to be measured at a desired rotational peripheral speed (Vr), A moving means for moving the slip roller along the surface of the object to be measured at a desired moving speed (Vf); a pressing force setting means for setting a pressing force in the normal direction of the slip roller against the surface of the object to be measured; A pressing force detecting means for detecting the pressing force; and a tangential force detecting means for detecting a tangential force applied to the slip roller when the slip roller moves while rotating, and a rotational peripheral speed (Vr) of the slip roller. ) And the moving speed (Vf) are different, and the friction evaluation amount on the surface of the object to be measured can be measured while slipping the slip roller on the surface of the object to be measured. And it features.

According to this apparatus, the friction coefficient and the like are measured while rolling the slip roller at a desired slip rate on the surface of the object to be measured while pressing the slip roller with the desired pressing force by the pressing force setting means. can do. At this time, the slip roller is rotated at the rotational peripheral speed Vr by the rotating means and moved at the moving speed Vf by the moving means, and by appropriately setting these Vr and Vf (Vr ≠ Vf), the slip rate S = ( Vr−Vf) / {(Vr + Vf) / 2} can be set to an arbitrary minute state. Therefore, in addition to the completely sliding slip state of Vr = 0 (S = −200%) and the completely slipping slip state of Vf = 0 (S = 200%) that can be measured even with a conventional apparatus, a micro slip (slip rate) It is possible to measure a friction evaluation amount (such as a friction coefficient) in a state of about -10% to + 10%. In addition, since the frictional force in a minute slip state can be measured, for example, the influence of dust or the like attached to the surface of the object to be measured on the frictional force can be analyzed.
At the time of measurement, in addition to rolling the slip roller with the rotational peripheral speed Vr and the moving speed Vf being constant (therefore, the slip ratio S is constant), the slip roller is rolled while changing the slip ratio S from the sliding area to the idling area. It can also be made.

  A friction evaluation amount measuring apparatus according to the present invention includes a fixed frame fixed to an object to be measured, a guide extending in a longitudinal direction of the fixed frame, and a slide mechanism having a slider slidably provided along the guide. A measurement frame swingably provided on the slider of the slide mechanism, a moving means for moving the measurement frame and the slider along the guide, a slip roller rotatably attached to the measurement frame, A rotating means for rotating the slip roller on the surface of the object to be measured; a pressing force setting mechanism for setting a pressing force in the normal direction of the slip roller to the surface of the object to be measured, provided on the measurement frame; A pressing force detecting means for detecting the pressing force of the slip roller; and three places around the slip roller. An auxiliary roller that is rotatably attached to the measurement frame and each rolls against the surface of the object to be measured; and when the measurement frame is moved by the moving means while the slip roller is rotated by the rotating means. And a tangential force detecting means for detecting a tangential force applied to the slip roller.

  When using this apparatus, first, the entire apparatus is placed on the object to be measured, and the fixed frame is fixed. At this time, the three auxiliary rollers hit the surface of the object to be measured. Next, the pressing force setting mechanism is operated to press the slip roller against the surface to be measured. The pressing force at this time is detected by the pressing force detecting means. Then, the rotating means and the moving means are driven simultaneously to control the rotational peripheral speed Vr of the slip roller and the moving speed Vf of the measurement frame that supports the slip roller, thereby rolling the slip roller in a desired slip state. The tangential force applied to the slip roller at this time is detected by the tangential force detection means. Even in this device, the slip roller can be rolled at the desired microslip rate while pressing the slip roller with the desired pressing force on the surface to be measured. In addition to the complete slip state in which the contact surface is stationary (Vr or Vf is 0), it is possible to measure the friction evaluation amount in the minute slip state.

In the friction evaluation amount measuring apparatus according to the present invention, the measurement frame is provided on the slider of the slide mechanism so as to be swingable. The outer frame rotatably supports the auxiliary rollers, and swings on the outer frame. And an inner frame that rotatably supports the slip roller.
In this case, a double swing structure is realized in which the outer frame swings with respect to the slide mechanism and the inner frame swings with respect to the outer frame, and the posture of the slip roller during measurement is maintained by three auxiliary rollers. Is done. Therefore, even if the surface of the object to be measured is curved, it can be rolled along the curved surface while keeping the slip roller in a desired posture.

In the friction evaluation amount measuring apparatus according to the present invention, the tangential force detection means may be disposed between the inner frame and the outer frame.
In this case, since the pressing force detection means and the tangential force detection means are arranged close to the slip roller, the measurement error can be reduced.
In addition, a load cell etc. can be used as each detection means.

In the friction evaluation amount measuring apparatus according to the present invention, the moving means includes a flexible rack that is detachably disposed on the surface of the object to be measured, a driving motor provided on the measurement frame, and an output of the driving motor. A pinion provided on the shaft and meshing with the flexible rack.
For example, when the object to be measured is a tread of a railway wheel, a flexible rack can be disposed on the top of the wheel flange, and a pinion can be meshed with this to drive the measurement frame. Since the flexible rack can be arranged concentrically with the rotationally symmetric curved surface to be measured, it is easy to perform measurement while keeping the measurement frame driving (pinion meshing movement) and the slip roller moving speed Vf constant.

In the friction evaluation amount measuring apparatus according to the present invention, the rotating means is bridged between a drive motor provided in the measurement frame, an output shaft of the drive motor, and a support shaft of the slip roller. And a timing belt.
If this timing belt and the flexible rack of the moving means are used and the moving direction of the slip roller is constant, adverse effects such as slippage and backlash of the drive system of the measurement frame and slip roller can be reduced. Furthermore, if the pinion meshing with the flexible rack is replaced with a no-backlash gear, the adverse effect of backlash when the direction of the slip is reversed, such as slipping from slipping to slipping or vice versa, can be reduced.

In the friction evaluation amount measuring apparatus according to the present invention, the fixing frame may be provided with fixing means for detachably fixing the fixing frame to the object to be measured.
By using this fixing mechanism, the apparatus can be easily fixed to and unlocked from the object to be measured. Therefore, it does not take time to move the apparatus to another measurement site, and many measurement sites can be measured in a short time.

  In the friction evaluation amount measuring method of the present invention, the slip roller is pressed against the surface of the object to be measured, the pressing force in the normal direction of the slip roller with respect to the surface of the object to be measured is set, and the slip roller is measured While rotating at a desired rotational peripheral speed (Vr) on the surface of the substrate, the object is moved along the surface of the object to be measured at a desired moving speed (Vf), and these rotating peripheral speed (Vr) and moving speed (Vf) are The friction evaluation amount on the surface of the object to be measured is measured while making the slip roller slip on the surface of the object to be measured.

  ADVANTAGE OF THE INVENTION According to this invention, the friction evaluation amount measuring apparatus and method which can measure friction evaluation amounts, such as a friction coefficient in a micro slip state, can be provided.

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments of the present invention will be described below with reference to the drawings. In the present embodiment, the object to be measured is a wheel of a railway vehicle.
FIG. 1 is an overall view (front view) of the friction evaluation amount measuring apparatus according to the present embodiment.
FIG. 2 is a side sectional view of the friction evaluation amount measuring apparatus.
FIG. 3 is a plan sectional view (sectional view taken along line XX in FIG. 1) of the friction evaluation amount measuring apparatus.
FIG. 4 is a top view of a measuring unit of the friction evaluation amount measuring apparatus.
FIG. 5 is an exploded perspective view of the outer frame portion of the measurement unit and the connection structure thereof in the friction evaluation amount measuring apparatus.
FIG. 6 is a perspective view of the inner frame part and the measurement head part of the measurement part of the friction evaluation amount measuring apparatus.
In the following description, “up / down / left / right / front / rear” refers to the directions of arrows in each figure unless otherwise specified.

The friction evaluation amount measuring apparatus 1 shown in FIGS. 1 to 6 includes the following parts (A) to (F).
(A) The fixed frame part 10 fixed to the wheel C which is an object to be measured. The fixed frame portion 10 includes a fixing magnet 15 (fixing mechanism), a linear guide 20 (sliding mechanism) having a guide 21 and a slider 22.
(B) The measuring unit 30 attached to the slider 22 of the linear guide 20 inside the fixed frame unit 10. The measurement unit 30 includes an outer frame portion 40 (see FIG. 5) attached to the slider 22 so as to be swingable, an inner frame portion 50 (see FIG. 6) attached to the outer frame portion 40 so as to be swingable, and an inner frame. The measuring head unit 62 (see FIG. 6) is disposed inside the unit 50.

(C) Slip roller 60 and its rotation mechanism 61 provided in the measurement head part 62 of the measurement part 30 (refer FIG. 2, FIG. 6).
(D) A pressing force setting mechanism 71 of the slip roller 60 provided in the measuring head unit 62 of the measuring unit 30. The pressing force setting mechanism 71 includes a load cell 79 (detecting means) for detecting the pressing force of the slip roller 60.
(E) The tangential force detection unit 80 assembled to the outer frame unit 50 of the measurement unit 30. The tangential force detection unit 80 includes a tangential force detection load cell 81 (detection means).
(F) A moving mechanism 91 that moves the measuring unit 30 (see FIG. 2).

Details of each part will be described below.
(A) Fixed frame portion 10
As shown in FIGS. 1 and 2, the fixed frame portion 10 includes an upper plate 11 and a vertical frame 12. The vertical frame 12 is suspended from the left end of the upper plate 11 (see FIG. 2). Positioning bars 13 extending in the left-right direction are provided at both lower corners of the vertical frame 12 (see FIG. 1). Each positioning rod 13 hits the flange portion Cf of the wheel C when the apparatus 1 is installed, and positions the entire apparatus 1. The hole 11a (see FIG. 2) opened in the upper plate 11 of the fixed frame portion 10 is for passing a tool (not shown) for operating a pressing force setting mechanism 71 described in detail later. .

  A fixing magnet (permanent magnet or electromagnet) 15 is provided at each of the front and rear lower ends of the vertical frame 12. Each fixing magnet 15 is attracted to the side surface of the flange portion Cf of the wheel C when the device 1 is installed, and fixes the entire device 1 in a fixed position. A lever 16 is attached to the fixing magnet 15, and a magnetic force is generated according to the switching of the lever 16. By using such a fixing magnet 15, it is possible to easily fix the device 1 to the wheel C and release the fixing at the time of installation in another place.

  As shown in FIGS. 1 and 2 (and FIG. 5), a linear guide 20 is provided on the lower surface of the upper plate 11 of the fixed frame portion 10. The linear guide 20 includes a guide 21 that extends in the longitudinal direction (front-rear direction) of the upper plate 11 and a slider 22 that is slidable along the guide 21. The guide 21 is fixed to the lower surface of the upper plate 11, and a slider 22 is slidably provided on the guide 21.

(B) Measuring unit 30
As described above, the measurement unit 30 includes the outer frame unit 40, the inner frame unit 50, and the measurement head unit 62.
As shown most clearly in FIG. 5, the upper portion of the outer frame portion 40 is swingably connected to the slider 22 of the linear guide 20 via a spring receiving plate 31, a support plate 32, and a connecting coil spring 35. The spring receiving plate 31 is fixed to the lower surface of the slider 22 (see FIG. 2). A support plate 32 is fixed to the lower surface of the spring receiving plate 31 with screws 39. A pair of support pins 33 project from the left and right side surfaces of the support plate 32 facing each other.

  Engagement protrusions 41 of the outer frame portion 40 are engaged with the support pins 33 of the support plate 32, respectively. Two engagement protrusions 41 are formed on the left and right ends of the upper surface of the outer frame portion 40 corresponding to the left and right support pins 33, respectively, and support pins are provided in the space between the two engagement protrusions 41. 33 is fitted (see FIG. 1). Further, the lower four corners of the spring receiving plate 31 and the upper four corners of the outer frame portion 40 are connected by a connecting coil spring 35. A reinforcing pin 37 is inserted in each coupling coil spring 35. Each reinforcing pin 37 is made of a brass material or the like, and is attached to four corners on the upper surface of the outer frame portion 40. These reinforcing pins 37 play a role in preventing buckling of the coupling coil spring 35.

  Although the displacement of the front and rear horizontal direction of the entire outer frame portion 40 is restricted by the engagement protrusions 41 coming into contact with both support pins 33, the outer frame portion 40 can swing back and forth with both support pins 33 as fulcrums, and Slightly slidable in the direction. Each connection coil spring 35 urges the entire outer frame portion 40 downward while linking and supporting the outer frame portion 40 with respect to the spring receiving plate 31. When the outer frame portion 40 swings in the front-rear direction, each coupling coil spring 35 expands and contracts and bends (see FIGS. 8 and 9 described later).

  The outer frame part 40 includes three leg parts (two left and right leg parts 43 on the left side and a V-shaped leg part 44 on the right side). An auxiliary roller 45 is rotatably attached to the lower ends of the leg portions 43 and 44, respectively. These auxiliary rollers 45 are located at three positions around the slip roller 60 attached to the measuring head unit 62, and each of them is in contact with the tread surface Cs of the wheel C and rolls when the apparatus 1 is installed on the wheel C.

  An inner frame 50 is swingably provided inside the outer frame 40. As easily shown in FIGS. 2 and 6, the inner frame portion 50 has an L shape. Support pins 53 protrude from the left and right side surfaces of the upper end of the inner frame portion 50, respectively. Each support pin 53 is fitted in a bearing 47 (see FIGS. 1 and 2) embedded in the left and right side surfaces of the outer frame portion 40, respectively. The inner frame portion 50 can swing in the front-rear direction with the support pin 53 as a fulcrum. In the present embodiment, a double swing structure is realized in which the outer frame portion 40 swings with respect to the fixed frame 10 and the linear guide 20, and the inner frame portion 50 swings with respect to the outer frame portion 40. The posture of the slip roller 60 during measurement is maintained by the three auxiliary rollers 45. Therefore, even the curved tread surface Cs can be rolled along the tread surface Cs while keeping the slip roller 60 in a desired posture.

  A measurement head unit 62 is disposed inside the inner frame unit 50. A linear guide 55 including a guide 56 and a slider 57 is interposed between the measurement head unit 62 and the inner frame unit 50. The linear guide 55 swings integrally with the inner frame portion 50. However, when the pressing screw 75 of the pressing force setting mechanism 71, which will be described later in detail, is screwed in, the linear guide 55 moves relative to the guide 56 on the inner frame portion 50 side. The slider 57 slides slightly downward together with the measuring head unit 62. The measurement head unit 62 is provided with a slip roller 60, a rotation mechanism 61, and a pressing force setting mechanism 71, which will be described later.

(C) Slip roller 60 and its rotation mechanism 61
The slip roller 60 is rotated by driving of the rotation mechanism 61 while being in contact with the tread surface Cs of the wheel C. As easily shown in FIGS. 2 and 6, the slip roller 60 is rotatably provided at the bifurcated lower end of the measurement head portion 62 via a support shaft 60 a. A stage 64 (see FIG. 2) projects outward from the right side surface of the measurement head unit 62, and a pulse motor 63 of the rotation mechanism 61 is disposed on the stage 64.

  A gear 63 g is provided on the output shaft 63 a of the pulse motor 63. On the other hand, the support shaft 60a of the slip roller 60 protrudes from the side surface of the measurement head 62, and a gear 60g is also provided here. A loop-like timing belt 65 is stretched around these gears 60g and 63g. When the pulse motor 63 of the rotation mechanism 61 is driven to rotate the output shaft 63a and the gear 63g, the gear 60g and the support shaft 60a are rotated via the timing belt 65, and the slip roller 60 is rotated.

(D) Pressing force setting mechanism 71
The pressing force setting mechanism 71 is a mechanism for manually setting the pressing load of the slip roller 60 when the tread surface Cs of the wheel C is measured. By operating the pressing force setting mechanism 71, the pressing load of the slip roller 60 necessary for calculating the creep coefficient can be adjusted. As clearly shown in FIGS. 2 and 6, the pressing force setting mechanism 71 includes a pressing spring 73 disposed inside the hole 62 a of the measurement head unit 62. The upper end of the pressing spring 73 is engaged with the piston 76 at the lower end of the pressing screw 75.

  The upper end of the pressing screw 75 extends from the lower side to the vicinity of the upper plate 11 of the fixed frame 10 through the hole 40a on the upper surface of the outer frame 40, the hole 32a of the support plate 32, and the hole 31a of the spring receiving plate 31. Yes. The pressing screw 75 can be rotated by inserting an L-shaped hexagon wrench (not shown) or the like from the hole 11 a (see FIG. 2) of the upper plate 11. The screw portion of the pressing screw 75 is engaged with the screw hole on the upper surface of the inner plate portion 50. The pressing screw 75 can be advanced and retracted in the vertical direction while being engaged with the screw hole of the inner plate portion 50. When the pressing screw 75 moves back and forth, the piston 76 moves up and down while being guided by the hole 62a in the measuring head 62.

  The lower end of the pressing spring 73 is engaged with the pressing member 78. On the lower side of the pressing member 78, a pressing force detection load cell 79 is disposed at the bottom of the hole 62a of the measuring head unit 62. The load cell 79 is located immediately above the slip roller 60. The set value of the pressing force by the pressing force setting mechanism 71 (the amount by which the pressing screw 75 is screwed) is detected by the load cell 79 via the piston 76 → the pressing spring 73 → the pressing member 78. The detection value of the load cell 79 is displayed on a monitor (not shown).

(E) Tangent force detector 80
As shown in FIGS. 1, 3, and 6, the tangential force detection unit 80 includes a tangential force detection load cell 81. The load cell 81 is disposed near the load cell 79 for detecting the pressing force described above so as to be in contact with the rear end surface of the measurement head unit 62. As described above, since the load cell 79 is located immediately above the slip roller 60 and the load cell 81 is also disposed in the vicinity of the slip roller 60, measurement errors can be reduced.

The tangential force detection load cell 81 is fixed to the front end surface of the fixed block 83. The fixed block 83 is fixed to the outer frame portion 40 of the measurement unit 30 with a fixed plate 85. As shown in FIG. 1, a coil spring 89 is provided between the outer frame portion 40 and the measurement head portion 62. With this coil spring 89, the measurement head 62 is drawn toward the outer frame 40, and the contact state between the measurement head 62 and the load cell 81 is always ensured. The detection value of the load cell 81 is sent to a control unit (not shown), and is converted into a creep force and a creep coefficient and displayed by the control unit.
The detailed measurement principle will be described later with reference to FIG.

(F) Movement mechanism 91
The moving mechanism 91 is a mechanism that moves the entire measuring unit 30 including the slip roller 60 along the linear guide 20, and is a drive system that is independent of the rotation mechanism 61 described above. As shown in FIGS. 1 to 3, the moving mechanism 91 includes a flexible rack 93. The flexible rack 93 is separate from the main body of the apparatus 1 and is detachably disposed on the top of the flange portion Cf of the wheel C during measurement. Since the flexible rack 93 can be arranged concentrically with the tread surface Cs of the wheel C, it is easy to perform measurement while keeping the driving of the measuring unit 30 and the moving speed of the slip roller 60 constant.

  As shown in FIGS. 2 and 3, a stage 49 projects from the left side surface of the outer frame portion 40 of the measurement unit 30 to the left side of the drawing. A pulse motor 92 is provided on the lower surface of the stage 49 via a coil spring 98. A pinion 94 that meshes with the flexible rack 93 is provided on the output shaft 92 a of the pulse motor 92. At the front end of the stage 49, a side wall 49a hanging downward is formed. A linear guide 95 (see FIG. 3) including a guide 96 and a slider 97 is interposed between the side wall 49 a and the pulse motor 92. In the linear guide 95, when the pinion 94 is engaged with the flexible rack 93 and rotated, the slider 97 slides slightly together with the pulse motor 92 with respect to the guide 96 on the side wall 49a side.

Here, the measurement principle of the friction evaluation amount (friction coefficient) using the friction evaluation amount measuring apparatus 1 having the above-described configuration will be described with reference to FIG.
FIG. 7 is a conceptual diagram for explaining the measurement principle of the friction evaluation amount measuring apparatus according to the present embodiment.
FIG. 7 conceptually shows the measuring unit 30, the auxiliary roller 45, the slip roller 60, and the pressing force setting mechanism 71. In this figure, R1 indicates the tread surface Cs of the wheel C, and R2 indicates a meshing line between the flexible rack 93 and the pinion 94 of the moving mechanism 91. P1 indicates the detection action point of the tangential force detection load cell 81, P2 indicates the detection action point of the pressing force detection load cell 79, and P3 indicates the swing of the support pin 53 provided in the inner frame portion 50 of the measurement unit 30. Indicates the fulcrum. Further, the vertical length from the swing fulcrum P3 to the detection action point P1 is indicated by L1, and the vertical length from the swing fulcrum P3 to the contact point with the tread surface Cs of the slip roller 60 is indicated by L2. The radius of the slip roller 60 is r. L1, L2, and r are values determined based on the specifications of the device 1.

  The slip roller 60 rotates clockwise in the figure at an angular velocity ω by driving the rotating mechanism 61, and the measuring unit 30 moves along the locus R2 from the left side to the right side in the figure at a speed V by driving the moving mechanism 91. And Further, the pressing force setting force by the pressing force setting mechanism 71 (that is, a value obtained by correcting the influence of gravity or the like on the detection value of the pressing force detection load cell 79 at the detection action point P2) is set as W, and The pressing force (that is, a value obtained by correcting the influence of the coil spring 89 on the detection value of the tangential force detection load cell 81 at the detection action point P1) is F.

On the tread surface Cs of the wheel C, the slip roller 60 is rolled at a desired slip rate S in a state where the slip roller 60 is pressed with a desired pressing force W by the pressing force setting mechanism 71. At this time, the rotational peripheral speed of the slip roller 60 (substance speed of the slip roller 60 on the contact surface) Vr is:
Vr = r · ω
The moving speed of the slip roller 60 (substance speed of the tread surface Cs of the wheel C on the contact surface) Vf is
Vf = (R1 / R2) · V
It becomes. And the slip ratio S at the time of rolling of the slip roller 60 is:
S = (Vr−Vf) / {(Vr + Vf) / 2}
Given in.

  When the slip roller 60 rolls, the rotational peripheral speed Vr and the moving speed Vf are made different (if the rotating peripheral speed Vr and the moving speed Vf are equal, the slip ratio S = 0, the rotating peripheral speed Vr (The condition of the moving speed Vf is necessary.) When the angular speed ω and the speed V are appropriately controlled, the slip roller 60 is rolled at a desired minute slip ratio (about −10% to + 10%). Can do. And the friction evaluation amount (friction coefficient) in such a micro slip state can be measured. In addition, at the time of measurement, the slip roller 60 can be rolled while changing the slip rate S in addition to rolling the slip roller 60 with the rotational peripheral speed Vr and the moving speed Vf being constant (therefore, the slip rate S being constant). .

In this manner, the pressing force F of the measuring head unit 62 is detected by the load cell 81 for detecting the tangential force while rolling the slip roller 60 at a desired slip rate S. Using this pressing force F, the creep force (tangential force) Fc of the tread surface Cs of the wheel C is Fc = (L1 / L2) · F
Is calculated by Further, the creep coefficient Rc is Rc = Fc / W
Is calculated by

Next, the overall operation of the friction evaluation amount measuring apparatus 1 will be described mainly with reference to FIGS. 1, 8, and 9.
FIG. 8 is an overall view showing a state at the start of measurement of the friction evaluation amount measuring apparatus according to the present embodiment.
FIG. 9 is an overall view showing a state at the end of measurement of the friction evaluation amount measuring apparatus according to the present embodiment.

The friction evaluation amount measuring apparatus 1 according to the present embodiment is used in the following procedures (1) to (3).
(1) First, as a preparation stage, the measuring unit 30 is moved to the front end moving origin inside the fixed frame 10 (see FIG. 8). Then, after the entire apparatus 1 is placed so that the positioning rod 13 of the fixed frame 10 hits the top of the flange portion Cf of the wheel C, the apparatus 1 is fixed to the wheel C using the fixing magnet 15. At this time, three auxiliary rollers 45 around the slip roller 60 hit the tread surface Cs of the wheel C. At substantially the same time, the flexible rack 93 of the moving mechanism 91 is attached to the top of the flange portion Cf of the wheel C, and the pinion 94 (see FIGS. 2 and 3) is engaged.

(2) The pressing force setting mechanism 71 is operated to adjust the pressing load W against the tread Cs of the slip roller 60 (see FIG. 2). The pressing force setting mechanism 71 is operated by inserting an L-shaped hexagon wrench (not shown) or the like from the hole 11a of the upper plate 11 and engaging with the upper end of the pressing screw 75 to rotate. Then, the pressing screw 75 is screwed in a state of being engaged with the screw hole of the inner plate portion 50, and this screwing amount is detected as a load W by the load cell 79 through the piston 76 → the pressing spring 73 → the pressing member 78. Is done. As described above, the detection value W of the load cell 79 can be identified by a monitor (not shown).

(3) The pulse motor 63 of the rotating mechanism 61 and the pulse motor 92 of the moving mechanism 91 are driven simultaneously. Then, the slip roller 60 moves at the moving speed Vf together with the measuring unit 30 while rotating at the rotational peripheral speed Vr while being pressed against the tread surface Cs of the wheel C (FIG. 8 → FIG. 1 → FIG. 9). The movement range of the measuring unit 30 can be regulated by controlling the pulse motor 92 or using an optical sensor (not shown) attached to the start / end points. At this time, as described above, the slip roller 60 can be rolled in a minute slip state by appropriately controlling the rotational peripheral speed Vr and the moving speed Vf.

  In the measurement unit 30, the outer frame 40 swings with respect to the fixed frame 10 and the linear guide 20 with the support pin 33 of the support plate 32 as a fulcrum, and each connection coil spring 35 expands / contracts and bends. The whole is urged toward the tread Cs. The inner frame 50 swings with respect to the outer frame 40 with the support pin 53 as a fulcrum, and is biased toward the outer frame 40 by a coil spring 89. The posture of the slip roller 60 is maintained by the three auxiliary rollers 45, and the curved surface followability of the measuring head unit 62 and the pinion 94 is compensated by the linear guides 55 and 95, respectively. As a result, the slip roller 60 rolls along the tread surface Cs while being maintained in a desired posture.

  During this rolling, the pressing force F of the measuring head unit 30 corresponding to the tangential force applied to the slip roller 60 is detected by the tangential force detection load cell 81. Since the measurement head unit 62 is attracted to the outer frame unit 40 side (load cell 81 side) by the coil spring 89, the contact state between the measurement head unit 62 and the load cell 81 is always ensured satisfactorily. The detection value F of the load cell 81 is sent to a control unit (not shown), and is converted into a creep force Fc and a creep coefficient Rc and displayed by the control unit. At the time of measurement, as described above, the load cell 79 is positioned immediately above the slip roller 60 and the load cell 81 is close to the slip roller 60, so that the measurement error is smaller.

  In the series of operations (3), the timing belt 65 is used as the rotation transmission means of the rotation mechanism 61 and the flexible rack 93 is used as the driving means of the movement mechanism 91, so that the rolling direction of the slip roller 60 is constant. In addition, adverse effects such as slippage and backlash of the drive system of the measuring unit 30 and the slip roller 60 are reduced. If a no-backlash gear that meshes with the flexible rack 93 is used in place of the pinion 94, it is possible to reduce the adverse effect of backlash even in measurement that shifts from slipping to sliding.

It is a general view (front view) of the friction evaluation amount measuring apparatus according to the present embodiment. It is side surface sectional drawing of the same friction evaluation amount measuring apparatus. It is a plane sectional view (XX sectional view of Drawing 1) of the friction evaluation amount measuring device. It is a top view of the measurement part of the friction evaluation amount measuring apparatus. It is a disassembled perspective view of the outer frame part of the measurement part of the friction evaluation amount measuring apparatus, and its connection structure. It is a perspective view of the inner frame part and measurement head part of the measurement part of the friction evaluation amount measuring apparatus. It is a conceptual diagram for demonstrating the measurement principle of the friction evaluation amount measuring apparatus which concerns on this Embodiment. It is a general view which shows the state at the time of the measurement start of the friction evaluation amount measuring apparatus which concerns on this Embodiment. It is a general view which shows the state at the time of completion | finish of a measurement of the friction evaluation amount measuring apparatus which concerns on this Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Friction evaluation amount measuring apparatus 10 Fixed frame part 11 Upper plate 12 Vertical frame 13 Positioning rod 15 Fixing magnet 16 Lever 20 Linear guide 21 Guide 22 Slider 30 Measuring part 31 Spring receiving plate 32 Support plate 33 Support pin 35 Connecting coil spring 37 Reinforcement Pin 40 Outer frame 41 Engagement protrusion 43, 44 Leg 45 Auxiliary roller 47 Bearing 50 Inner frame 53 Support pin 55 Linear guide 60 Slip roller 60a Support shaft 60g, 63g Gear 61 Rotating mechanism 62 Measuring head 62a Hole 63 Pulse motor 63a Output shaft 65 Timing belt 71 Pressing force setting mechanism 73 Pressing spring 75 Pressing screw 76 Piston 78 Pressing member 79 Pressing load detecting load cell 80 Tangent force detecting unit 81 Load for detecting tangential force Le 83 fixed block 85 fixed plate 89 coil spring 91 moving mechanism 92 pulse motor 92a output shaft 93 flexible rack 94-pinion 95 linear guide 98 coil spring

Claims (8)

A slip roller pressed against the surface of the object to be measured;
A rotating means for rotating the slip roller on the surface of the object to be measured at a desired rotational peripheral speed (Vr);
Moving means for moving the slip roller along the surface of the object to be measured at a desired moving speed (Vf);
A pressing force setting means for setting a pressing force in the normal direction of the slip roller with respect to the surface of the object to be measured;
A pressing force detecting means for detecting the pressing force;
Tangential force detection means for detecting a tangential force applied to the slip roller when the slip roller moves while rotating, and
The rotational evaluation speed (Vr) and the moving speed (Vf) of the slip roller are made different, and the friction evaluation amount on the surface of the object to be measured can be measured while the slip roller slips on the surface of the object to be measured. A friction evaluation amount measuring device. A fixed frame fixed to the object to be measured;
A slide mechanism having a guide extending in the longitudinal direction of the fixed frame, and a slider slidably provided along the guide;
A measurement frame provided on the slider of the slide mechanism so as to be swingable;
Moving means for moving the measurement frame and the slider along the guide;
A slip roller rotatably attached to the measurement frame;
Rotating means for rotating the slip roller on the surface of the object to be measured;
A pressing force setting mechanism that is provided in the measurement frame and sets a pressing force in a normal direction of the slip roller with respect to the surface of the object to be measured;
A pressing force detecting means for detecting the pressing force of the slip roller;
An auxiliary roller that is rotatably attached to the measurement frame at three locations around the slip roller, and each rolls against the surface of the object to be measured;
A tangential force detecting means for detecting a tangential force applied to the slip roller when the measuring means is moved by the moving means while rotating the slip roller by the rotating means;
A friction evaluation amount measuring apparatus comprising: The measurement frame is
An outer frame provided rotatably on the slider of the slide mechanism and rotatably supporting the auxiliary rollers;
An inner frame that is swingably provided on the outer frame, and that rotatably supports the slip roller;
The friction evaluation amount measuring apparatus according to claim 2, further comprising:   4. The friction evaluation amount measuring apparatus according to claim 3, wherein the tangential force detecting means is disposed between the inner frame and the outer frame. The moving means is
A flexible rack detachably disposed on the surface of the object to be measured;
A driving motor provided in the measurement frame;
A pinion provided on the output shaft of the drive motor and meshing with the flexible rack;
The friction evaluation amount measuring apparatus according to claim 2, wherein the friction evaluation amount measuring apparatus is provided. The rotating means is
A driving motor provided in the measurement frame;
A timing belt spanned between the output shaft of the drive motor and the support shaft of the slip roller;
The friction evaluation amount measuring apparatus according to claim 2, comprising:   The friction evaluation amount measuring apparatus according to any one of claims 2 to 6, wherein the fixing frame is provided with fixing means for detachably fixing the fixing frame to an object to be measured. Press the slip roller against the surface of the object to be measured, set the pressing force in the normal direction of the slip roller against the surface of the object to be measured,
While rotating the slip roller on the surface of the object to be measured at a desired rotational peripheral speed (Vr), the slip roller is moved at a desired moving speed (Vf) along the surface of the object to be measured.
Friction evaluation characterized by measuring the friction evaluation amount on the surface of the object to be measured while making the rotational peripheral speed (Vr) and the moving speed (Vf) different and slipping the slip roller on the surface of the object to be measured. Quantity measuring method.

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