JP2007333703A - Apparatus for measuring frictional coefficient - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for measuring frictional coefficient capable of measuring the friction coefficient under a condition similar to the operating state of a tire, easily measuring the relation between the coefficient of friction and grounding load, and which is compact. <P>SOLUTION: The circumferential surface of a test strip 10 is brought to ground on a road surface, and the test strip 10 is rotated by a driving device 20, and the torque applied to the test strip 10 at above timing is detected by a torque detector 40. Since the frictional coefficient can be calculated based on the torque, the grounding load and the radius of the test strip 10, only a frictional force is generated, in a direction in which the test strip 10 is rolled, and the friction coefficient can be measured under the condition similar to the operating state of the tire. Furthermore, the grounding load that brings the circumferential surface of the test strip 10 to ground on the road surface can be adjusted arbitrarily, by using a grounding load adjusting mechanism 30. Moreover, the need for unnecessarily moving the test strip 10, the driving device 20 and the torque detector 40 is eliminated for measuring the frictional coefficient. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a friction coefficient measuring device that measures a friction coefficient between, for example, a tire rubber material and a road surface.

  Generally, this type of friction coefficient measuring device is used for tires that are provided so as to be movable in the vertical direction and are rotatably provided, and a plurality of tires attached to the outer peripheral surface of the lower surface of the disk-like member. Block-shaped rubber test pieces made of rubber material, each disk test piece is rotated from the road surface while rotating the disk-shaped member at a predetermined rotational speed, and the disk-shaped member is moved slowly downward Then, each rubber test piece is brought into contact with the road surface, and by utilizing the acceleration in the deceleration direction when the disk-like member decelerates due to the frictional resistance between each rubber test piece and the road surface, A device that measures frictional resistance is known (for example, see Patent Document 1).

As another friction coefficient measuring device, there are an apparatus main body that can be installed on a road surface, a disk upper member that is disposed at a predetermined interval between the apparatus main body and the road surface when the apparatus main body is installed on the road surface, A first motor that rotates the member at an arbitrary speed, and is disposed in the vicinity of the outer peripheral surface of the disk-shaped member, and is disposed so that the rotation shaft extends in the radial direction of the disk-shaped member, and the apparatus main body is used as a road surface. When installed, a disc-shaped rubber test piece made of a rubber material for tires whose outer peripheral surface contacts the road surface, a second motor for rotating the rubber test piece at an arbitrary speed, and between the rubber test piece and the second motor Provided with a torque cell for detecting a torque applied to the rubber test piece, and the rubber test piece rolling by rotating the rubber test piece with the second motor while rotating the disk-like member with the first motor. Friction between outer peripheral surface of road and road surface Those to be measured is known (for example, see Patent Document 2.).
Japanese Patent Publication No.3-10062 Japanese Patent Laid-Open No. 11-211652

  However, in the former friction coefficient measuring device, each rubber test piece is formed in a block shape, and the friction coefficient when the block-like rubber test piece is pressed against the road surface is measured. However, the conditions are greatly different from those of a tire that generates frictional resistance with the road surface, and there is a problem that the friction coefficient cannot be measured under conditions close to the tire use condition.

  In the latter friction coefficient measuring device, the friction coefficient can be measured while rolling a disk-shaped rubber test piece. In addition to the frictional force in the rolling direction, Since a vertical frictional force is generated, there is a problem that the conditions are different from the usage state of the tire.

  In addition, since the second motor, the load cell and the rubber test piece are attached to the upper surface of the disk-shaped member, and the disk-shaped member is rotated by the first motor, the second motor, the load cell and the rubber test piece are circular. The plate member moves in the circumferential direction, and there is a problem that the apparatus is enlarged by an amount that secures a space for the second motor, the load cell, and the rubber test piece to move.

  Furthermore, each of the friction coefficient measuring devices has a problem in that the relationship between the ground load and the friction coefficient cannot be measured because the ground load between the rubber test piece and the road surface cannot be easily changed.

  The present invention has been made in view of the above-mentioned problems, and the object of the present invention is to measure the friction coefficient under conditions close to the use state of the tire and to facilitate the relationship between the ground load and the friction coefficient. It is an object of the present invention to provide a friction coefficient measuring apparatus that can measure the temperature of the apparatus and reduce the size of the apparatus.

In order to achieve the above object, the present invention provides a friction coefficient measuring apparatus for measuring a friction coefficient between a predetermined material and a road surface, wherein the apparatus main body is provided with a predetermined grounding portion on the lower end side for grounding to the road surface; A rotatable test piece whose outer peripheral surface is made of a predetermined material and is supported by the apparatus main body so as to be movable in the vertical direction so that the rotation shaft is arranged substantially horizontally, a driving device for rotating the test piece, and the apparatus main body A grounding load adjusting means for grounding the outer peripheral surface of the test piece to the road surface with an arbitrary grounding load while the grounding part of the
A torque detector capable of detecting the torque applied to the test piece when the outer peripheral surface of the test piece contacts the road surface, and the friction coefficient between the outer peripheral surface of the test piece and the road surface based on the torque, the ground load and the radius of the test piece. Calculating means for calculating.

  Thus, the outer peripheral surface of the test piece is grounded to the road surface with an arbitrary ground load by the ground load adjusting means, the test piece is rotated by the driving device, and the torque applied to the test piece at that time is detected by the torque detector, Since the friction coefficient can be calculated based on the torque, the ground load, and the radius of the test piece, only the frictional force in the rolling direction is generated on the test piece, and the friction coefficient based on the frictional force is calculated. In addition, since the ground load for grounding the outer peripheral surface of the test piece to the road surface can be arbitrarily adjusted by the ground load adjusting means, the relationship between the ground load and the friction coefficient can be easily measured. Further, since the friction coefficient is measured by rotating the test piece, it is not necessary to move the test piece, the driving device and the torque detector unnecessarily in order to measure the friction coefficient. Can be planned.

  Further, the present invention provides a friction coefficient measuring apparatus for measuring a friction coefficient between a predetermined material and a road surface, and is arranged in an arbitrary direction in a predetermined direction while arranging the apparatus main body and the apparatus main body at a predetermined height position with respect to the road surface. The main body moving means that can move at a speed, and at least the outer peripheral surface is made of a predetermined material, and can be moved up and down on the apparatus main body so that the rotation axis is arranged substantially horizontally and substantially perpendicular to the moving direction of the apparatus main body. The test piece is supported on the surface of the test piece, the driving device for rotating the test piece, and the outer peripheral surface of the test piece with an arbitrary grounding load in a state where the apparatus main body is disposed at a predetermined height position with respect to the road surface. Ground load adjusting means for grounding to the road surface, a torque detector capable of detecting the torque applied to the test piece when the outer peripheral surface of the test piece is grounded to the road surface, and the test piece based on the torque, the ground load and the radius of the test piece Outer peripheral surface and road surface And a calculating means for calculating the coefficient of friction.

  Accordingly, the outer peripheral surface of the test piece is grounded to the road surface with an arbitrary ground load by the ground load adjusting means, the test piece is rotated by the driving device, and the apparatus main body is moved in a predetermined direction by the main body moving means. The torque applied to the test piece at that time is detected by a torque detector, and the friction coefficient can be calculated based on the torque, ground load and test piece radius, so that only the frictional force in the rolling direction is applied to the test piece. And a friction coefficient based on the friction force is calculated. In addition, since the ground load for grounding the outer peripheral surface of the test piece to the road surface can be arbitrarily adjusted by the ground load adjusting means, the relationship between the ground load and the friction coefficient can be easily measured. Further, since the friction coefficient is measured by rotating the test piece, it is not necessary to move the test piece, the driving device and the torque detector unnecessarily in order to measure the friction coefficient. Can be planned.

  According to the present invention, only the frictional force in the rolling direction is generated on the test piece, and the frictional coefficient can be calculated based on the frictional force. Therefore, the frictional coefficient can be measured under conditions close to the tire usage state. In addition, since the relationship between the contact load and the friction coefficient can be easily measured, it is extremely advantageous in measuring the friction coefficient of the tire rubber material. Furthermore, since the apparatus can be reduced in size, the apparatus can be easily carried, which is extremely advantageous in measuring the relationship between the type of road surface and the friction coefficient.

  1 to 8 show a first embodiment of the present invention. FIG. 1 is a sectional view of a friction coefficient measuring device, FIG. 2 is a sectional view taken along line AA in FIG. 1, and FIG. FIG. 4 is a plan view of the friction coefficient measuring device, FIG. 5 is a sectional view of the torque detector, FIG. 6 is a plan view of the control panel, FIG. 7 is a block diagram of the friction coefficient measuring device, and FIG. It is a flowchart which shows operation | movement of a part.

  The friction coefficient measuring apparatus according to the present embodiment rotates an apparatus main body 1 formed so that a lower end surface 1a serving as a grounding portion is in contact with a road surface, a test piece 10 provided in the apparatus main body 1, and a test piece 10. A driving device 20 to be grounded, a grounding load adjusting mechanism 30 that grounds the outer peripheral surface of the test piece 10 to the road surface with an arbitrary grounding load, a torque detector 40 that can detect torque applied to the test piece 10, and rotation of the test piece 10 A tachometer 50 capable of detecting the speed and a control panel 60 provided on the upper surface of the apparatus main body 1 are provided.

  The apparatus main body 1 is formed in a box shape having an open bottom surface, and has a pair of handles 1b on the top surface.

  The test piece 10 has an inner peripheral part 11 on a disc and a ring-shaped outer peripheral part 12 fitted to the outer peripheral surface of the inner peripheral part 11. The inner peripheral portion 11 is made of a metal material, and the outer peripheral portion 12 is made of a tire rubber material. The upper half of the test piece 10 is covered with a box-shaped first support member 13 having an open bottom surface. A support shaft 11 a is inserted through the inner peripheral portion 11, and one end side of the support shaft 11 a is rotatably supported on one side surface of the first support member 13. The other end side of the support shaft 11a is inserted through the other side surface of the first support member 13 and is rotatably supported by the second support member 14. A gear 15 is fixed to the other end side of the support shaft 13. Further, the test piece 10 rotates integrally with the support shaft 11a. The first support member 13 is supported by a guide rail 13a provided on one side surface of the apparatus body 1 so as to be movable in the vertical direction, and the second support member 14 is a guide rail 14a provided on the other side surface of the apparatus body 1. Is supported so as to be movable in the vertical direction. That is, the support shaft 11a and the test piece 10 are supported by the apparatus main body 1 so as to be movable in the vertical direction via the support members 13 and 14 and the guide rails 13a and 14a. The position of the support shaft 11a in the vertical direction is visible from a window 1c provided on one side surface of the apparatus body 1, and the window 1c is provided with a scale indicating the distance from the lower end surface 1a of the apparatus body 1. . Note that the first support member 13 and the second support member 14 may be integrally formed.

  The drive device 20 is formed of a known DC servo motor, and can rotate the drive shaft 20a at an arbitrary rotation speed. A gear 21 is fixed to the drive shaft 20a, and the gear 21 meshes with the gear 15 of the support shaft 11a. An attachment member 22 is fixed to the upper surface of the drive device 20, and the attachment member 22 is attached to the other side surface of the apparatus main body 1 by a plurality of bolts 22 a. Each bolt 22a is inserted through a long hole (not shown) provided on the other side surface of the apparatus main body 1, and the vertical position of the drive device 20 can be adjusted by loosening each bolt 22a.

  The ground load adjustment mechanism 30 is provided between an adjustment screw 31 that is screwed onto the upper surface of the apparatus main body 1 so as to be movable in the vertical direction, and a lower end surface of the adjustment screw 31 and an upper end surface of the first support member 13. And a spring 32. The adjustment screw 31 has a disk-like operation part 31a at the upper end, and the outer peripheral surface of the operation part 31a is knurled. The lower end of the adjustment screw 31 is formed in a disc shape, and a lock nut 31 b is screwed to the adjustment screw 31. The upper end of the spring 32 is fixed to the lower end surface of the adjustment screw 31, and the lower end of the spring 32 is fixed to the upper end surface of the first holding member 13. The spring 32 has a predetermined spring constant proportional to the amount of deformation. That is, the deformation amount of the spring 32 changes in proportion to the tightening amount of the adjustment screw 31, and the first support member 13 is biased downward according to the deformation amount of the spring 32. Accordingly, the ground load of the test piece 10 changes in proportion to the tightening amount of the adjusting screw 31. Further, a scale (not shown) indicating the ground load of the test piece 10 is provided on the side surface of the adjustment screw 31 so that the ground load of the test piece 10 can be easily adjusted by the tightening amount of the adjustment screw 31. The scale of the adjustment screw 31 shows the ground load in consideration of the weight of the test piece 10, the support shaft 11a, the first support member 13, the second support member 14, and the gear 15.

  The torque detector 40 includes a strain gauge 41 attached to the outer peripheral surface of the support shaft 11a, and a ring-shaped antenna 42 that covers a portion of the support shaft 11a to which the strain gauge 41 is attached over the entire circumference. . The antenna 42 can supply electric power to the strain gauge 41 without contact, and the strain gauge 41 can transmit the output voltage to the antenna 42 without contact. The strain gauge 21 is attached between the other side surface of the first support member 13 and the gear 15, and the antenna 22 is fixed to the first support member 13. The torque detector 40 can detect the torque applied between the support shaft 11a and the driving device 10, and the support shaft 11a and the test piece 10 rotate together. Therefore, the torque applied to the test piece 10 by the torque detector 40. Can be detected.

  The tachometer 50 includes a known rotary encoder and is fixed to the first support member 13. The tachometer 50 can detect the rotation speed of the support shaft 11a. Since the support shaft 11a and the test piece 10 rotate together, the rotation speed meter 50 can detect the rotation speed of the test piece 10.

  The control panel 60 includes a control unit 60 a made up of a known microcomputer, a display unit 61 provided on the upper surface of the control panel 60, a plurality of input buttons 62 provided on the upper surface of the control panel 60, and the control panel 60. And a start button 63 provided on the upper surface. The drive device 20, the torque detector 40, the tachometer 50, the display unit 61, each input button 62, and the start button 63 are connected to the control unit 60a. The display unit 61 includes a shaft height display unit 61a that displays the height position of the support shaft 11a with respect to the lower end surface 1a of the apparatus body 1, a ground load display unit 61b that displays the ground load of the test piece 10, and a sliding speed. And a measurement result display unit 61c for displaying the measurement result of the friction coefficient. Numerical values are input to the shaft height display portion 61a and the ground load display portion 61b by operating the input button 62 (see FIG. 6).

  In the friction coefficient measuring device configured as described above, when measuring the friction coefficient between the outer peripheral surface of the test piece 10 and the road surface, first, the device body 1 is placed on the road surface. Thereby, the lower end surface 1a of the apparatus main body 1 is grounded to the road surface, and the outer peripheral surface of the test piece 10 is grounded to the road surface. Here, since the test piece 10 is supported by the apparatus main body 1 so as to be movable in the vertical direction, the positions of the lower end surface 1 a of the apparatus main body 1 and the lower end surface of the test piece 10 coincide with each other.

  Next, the height position of the support shaft 11a is visually confirmed from the window 1c, and the value is input to the shaft height display portion 61a by each input button 62. Here, since the vertical positions of the lower end surface 1a of the apparatus main body 1 and the lower end surface of the test piece 10 coincide with each other, the position of the support shaft 11a shown in the window 1c coincides with the radius of the test piece 10. Subsequently, by tightening the adjustment screw 31, the test piece 10 is grounded to the road surface with an arbitrary grounding load, and the grounding load is input to the grounding load display unit 61 b by each input button 62.

  Next, the measurement of the friction coefficient is started by operating the start button 62. The operation of the control unit 60a at this time will be described with reference to the flowchart of FIG.

  First, when the start button 62 is operated (S1), the test piece 10 is rotated by the driving device 20 at a predetermined acceleration so that the rotation speed gradually increases (S2). Here, the predetermined acceleration is set in advance by each input button 62. Next, while the test piece 10 is rotating so as to gradually increase the rotational speed, the torque detector 40 detects the torque and the tachometer 50 detects the rotational speed at a predetermined number of times. (S3) The predetermined number of times and the predetermined time are set in advance by the input buttons 62. When the torque and the rotation speed are detected a predetermined number of times (S4), the rotation of the test piece 10 by the driving device 20 is stopped (S5).

  Next, the sliding speed of the test piece 10 corresponding to each rotational speed detected by the rotational speed meter 50 is calculated (S6). Since the sliding speed = the radius of the test piece 10 × the rotational speed of the test piece 10, the sliding speed = the value of the shaft height display portion 61 a × the detection result of the rotational speed meter 50 is calculated.

  Further, based on each torque detected by the torque detector 40, a friction coefficient between the outer peripheral surface of the test piece 10 and the road surface is calculated according to each sliding speed (S7). Coefficient of friction = tangential force of the grounding portion of the test piece 10 / ground load of the test piece 10; therefore, friction coefficient = (detection result of the torque detector 40 / value of the shaft height display portion 61a) / ground load. It is calculated from the value of the display unit 61b.

  Subsequently, the calculated sliding speeds and friction coefficients are displayed on the measurement result display unit 61c (S8, FIG. 6).

  Step 2 (S2) corresponds to the rotational speed control means described in the claims, Step 3 (S3) corresponds to the detection control means described in the claims, and Step 6 (S6) corresponds to the patent. Step 7 (S7) corresponds to the calculation means described in the claims.

  As described above, according to the present embodiment, the outer peripheral surface of the test piece 10 is grounded to the road surface with an arbitrary ground load by the ground load adjusting mechanism 30, and the test piece 10 is rotated by the driving device 20, and the test is performed at that time. Since the torque applied to the piece 10 is detected by the torque detector 40 and the friction coefficient can be calculated based on the torque, the ground load and the radius of the test piece 10, only the frictional force in the rolling direction is applied to the test piece 10. And a friction coefficient based on the frictional force is calculated. Therefore, the friction coefficient can be measured under conditions close to the tire usage state, which is extremely advantageous in measuring the friction coefficient of the tire rubber material.

  Further, since the ground load for grounding the outer peripheral surface of the test piece 10 to the road surface can be arbitrarily adjusted by the ground load adjusting mechanism 30, the relationship between the ground load and the friction coefficient can be easily measured. This is extremely advantageous in measuring the friction coefficient of rubber materials.

  Further, since the friction coefficient is measured by rotating the test piece 10, it is not necessary to move the test piece 10, the drive device 20 and the torque detector 40 unnecessarily in order to measure the friction coefficient. Can be miniaturized. That is, the device can be easily carried and is extremely advantageous in measuring the relationship between the type of road surface and the friction coefficient.

  Further, since the driving device 20 can arbitrarily set the rotation speed of the test piece 10, it can measure the relationship between the rotation speed of the test piece 10 and the friction coefficient, that is, the relationship between the sliding speed and the friction coefficient, This is extremely advantageous in measuring the friction coefficient of rubber materials for tires.

  Further, a tachometer 50 capable of detecting the rotation speed of the test piece 10 is provided, and the test piece 10 is rotated by the driving device 20 so as to gradually increase the rotation speed at an arbitrary acceleration. While the rotation speed is gradually increased, the torque detector 40 detects the torque for a predetermined number of times and the rotation speed meter 50 detects the rotation speed of the test piece 10. The sliding speed of the test piece 10 corresponding to each detected rotational speed is calculated, and the friction coefficient corresponding to each sliding speed based on each torque detected by the torque detector 40, the ground load and the radius of the test piece 10. , Each of which is calculated so that the relationship between slip speed and friction coefficient can be measured automatically, and the friction coefficient of tire rubber material can be measured. That it is extremely advantageous.

  In addition, since the measurement result display unit 61c for displaying the calculation result of the friction coefficient is provided, the measurement result of the friction coefficient can be easily confirmed, which is extremely advantageous in smoothly performing the measurement work.

  In this embodiment, the measurement result of the friction coefficient is displayed on the measurement result display unit 61c. However, a printer is separately provided on the control panel 60, and the measurement result of the friction coefficient is recorded by the printer. Is also possible. Furthermore, it is also possible to separately provide a storage medium in the control panel 60 and store the measurement result of the friction coefficient in the storage medium.

  In the present embodiment, the first support member 13 is urged downward by the spring 32 and the ground load of the test piece 10 is adjusted by the urging force of the spring 32. It is also possible to provide a weight capable of adjusting the ground load in place of the urging force, and to adjust the urging force of the test piece 10 by the weight.

  In the present embodiment, the torque detector 40 includes the strain gauge 41 attached to the outer peripheral surface of the support shaft 11a and the antenna 42 provided so as to cover the strain gauge 41. The torque can also be detected by measuring the relative torsion angles at two positions separated in the axial direction of the support shaft 11a using a pair of sensors, and a load cell known to the support shaft 11a. It is also possible to install.

  In the present embodiment, the position of the support shaft 11a shown in the window 1c is visually confirmed, and the value is input to the shaft height display portion 61a. However, the height of the support shaft 11a is shown. It is also possible to separately provide a displacement sensor capable of detecting the position so that the shaft height is automatically input to the shaft height display unit 61a based on the detection result of the displacement sensor.

  In the present embodiment, the grounding load of the test piece 10 is set by the adjusting screw 31 and the set grounding load is input to the grounding load input unit 61b. It is also possible to provide a load cell that can be detected separately so that the ground load is automatically input to the ground load input unit 61b based on the detection result of the load cell.

  In the present embodiment, the outer peripheral portion 12 of the test piece 10 is formed of a tire rubber material. However, the outer peripheral portion 12 is formed of another material such as a resin material, and the friction between the material and the road surface is shown. It is also possible to measure the coefficients.

  9 to 11 show a second embodiment of the present invention. FIG. 9 is a side view of the friction coefficient measuring device, FIG. 10 is a block diagram of the friction coefficient measuring device, and FIG. 11 shows the operation of the control unit. It is a flowchart. In addition, the same code | symbol is attached | subjected and shown to the component equivalent to 1st Embodiment.

  The friction coefficient measuring apparatus according to the present embodiment includes an apparatus main body 1, a test piece 10, a driving device 20, a ground load adjustment mechanism 30, a torque detector 40, a tachometer 50, and a control panel 60 that are the same as those in the first embodiment. The four wheels 70 that support the apparatus main body 1 and the speedometer 80 that detects the moving speed of the apparatus main body 1 from the rotational speed of the wheels 70 are provided.

  The apparatus main body 1 is formed to have a smaller height than in the case of the first embodiment, and the lower end side of the test piece 10 protrudes downward from the lower end surface 1 a of the apparatus main body 1. The scale provided on the window 1c indicates the height dimension of the support shaft 11a with respect to the road surface in a state where each wheel 70 is grounded.

  Each wheel 70 can be rotated in the same direction as the rotation direction of the test piece 10, and is rotated by the wheel driving device 71 at an arbitrary speed. The wheel drive device 71 can rotate the two rear wheels 70 of each wheel 70 at an arbitrary rotational speed. That is, each wheel 70 and the wheel drive device 71 can dispose the device main body 1 at a predetermined height position with respect to the road surface and can move the device main body 1 in the rotation direction of the test piece 10 at an arbitrary speed.

  The speedometer 80 is formed of a known rotary encoder, and is attached to one front wheel 70 among the wheels 70.

  The control unit 60 a is connected to the drive device 20, the torque detector 40, the rotation speed meter 50, the display unit 61, each input button 62, the start button 63, the wheel drive device 71, and the speedometer 80.

  In the friction coefficient measuring device configured as described above, when measuring the friction coefficient between the outer peripheral surface of the test piece 10 and the road surface, first, each wheel 70 of the device body 1 is grounded to the road surface. Thereby, the outer peripheral surface of the test piece 10 contacts the road surface. Here, since the test piece 10 is supported by the apparatus main body 1 so as to be movable in the vertical direction, the vertical positions of the lower end surface of each wheel 70 and the lower end surface of the test piece 10 coincide.

  Next, the height position of the support shaft 11a is visually confirmed from the window 1c, and the value is input to the shaft height display portion 61a by each input button 62. Here, the position of the support shaft 11 a shown in the window 1 c coincides with the radius of the test piece 10. Subsequently, by tightening the adjustment screw 31, the test piece 10 is grounded to the road surface with an arbitrary grounding load, and the grounding load is input to the grounding load display unit 61 b by each input button 62.

  Next, the measurement of the friction coefficient is started by operating the start button 62. The operation of the control unit 60a at this time will be described with reference to the flowchart of FIG.

  First, when the start button 62 is operated (S11), the test piece 10 is rotated at a predetermined speed by the driving device 20 (S12). The predetermined speed is set in advance by each input button 62. Subsequently, the apparatus main body 1 is moved at a predetermined acceleration so as to gradually increase in speed by the wheel drive device 71 (S13). The predetermined acceleration is set in advance by each input button 62. Next, while the test piece 10 rotates at a predetermined speed and the apparatus main body 1 moves so as to gradually increase in speed, the torque detector 40 detects the torque at a predetermined time and the predetermined number of times. The speed is detected by the speedometer 80 (S14). The predetermined number of times and the predetermined time are set in advance by the input buttons 62. When the torque and the speed are detected a predetermined number of times (S15), the rotation of the test piece 10 by the driving device 20 and the movement of the device main body 1 by the wheel driving device 71 are stopped (S16).

  Next, the slip ratio of the test piece 10 is calculated according to each speed detected by the speedometer 80 (S17). Since slip ratio = (vehicle speed−circumferential speed of tire outer peripheral surface) ÷ vehicle speed, slip ratio = (detection result of speed of main body 1−speed in tangential direction of grounding portion of test piece 10) ÷ device It is calculated from the detection result of the speed of the main body 1. Further, the speed in the tangential direction of the grounding portion of the test piece 10 is calculated by the value of the detection result of the tachometer 50 × the value of the shaft height display portion 61a.

  Further, based on each torque detected by the torque detector 40, a friction coefficient between the outer peripheral surface of the test piece 10 and the road surface is calculated according to each slip ratio (S18). Coefficient of friction = tangential force of the grounding portion of the test piece 10 / ground load of the test piece 10; therefore, friction coefficient = (detection result of the torque detector 40 / value of the shaft height display portion 61a) / ground load. It is calculated from the value of the display unit 61b.

  Subsequently, the calculated slip ratio and friction coefficient are displayed on the measurement result display unit 61c (S19).

  Step 12 (S12) corresponds to the rotational speed control means described in the claims, Step 13 (S13) corresponds to the movement speed control means described in the claims, and Step 14 (S14) corresponds to It corresponds to the detection control means described in the claims, step 17 (S17) corresponds to the slip ratio calculation means described in the claims, and step 18 (S18) corresponds to the calculation means described in the claims. It corresponds to.

  As described above, according to the present embodiment, the outer peripheral surface of the test piece 10 is grounded to the road surface with an arbitrary ground load by the ground load adjusting mechanism 30, the test piece 10 is rotated by the driving device 20, and wheel driving is performed. The apparatus main body 1 is moved in the rolling direction of the test piece 10 by the apparatus 71, and the torque applied to the test piece 10 at that time is detected by the torque detector 40, and based on the torque, the ground load and the radius of the test piece 10. Therefore, only the frictional force in the rolling direction is generated on the test piece 10, and the frictional coefficient based on the frictional force is calculated. Therefore, the friction coefficient can be measured under conditions close to the tire usage state, which is extremely advantageous in measuring the friction coefficient of the tire rubber material.

  Further, since the ground load for grounding the outer peripheral surface of the test piece 10 to the road surface can be arbitrarily adjusted by the ground load adjusting mechanism 30, the relationship between the ground load and the friction coefficient can be easily measured. This is extremely advantageous in measuring the friction coefficient of rubber materials.

  Further, since the friction coefficient is measured by rotating the test piece 10, it is not necessary to move the test piece 10, the drive device 20 and the torque detector 40 unnecessarily in order to measure the friction coefficient. Can be miniaturized. That is, the device can be easily carried and is extremely advantageous in measuring the relationship between the type of road surface and the friction coefficient.

  Further, since the drive device 20 can arbitrarily set the rotation speed of the test piece 10, it is possible to measure the relationship between the rotation speed of the test piece 10 and the friction coefficient, and to measure the friction coefficient of the tire rubber material. This is extremely advantageous.

  Further, a speedometer 80 capable of detecting the moving speed of the apparatus main body 1 is provided, and the test piece 10 is rotated at a predetermined rotation speed by the driving device 20, and the apparatus main body 1 is gradually increased by an arbitrary acceleration by the wheel driving device 71. And the test piece 10 is rotated at a predetermined rotation speed and the apparatus main body 1 is moved so that the speed gradually increases. And the speed of the apparatus main body 1 is detected by the speedometer 80, and the slip rate of the test piece 10 corresponding to each speed detected by the speedometer 80 is calculated and detected by the torque detector 40. Since the friction coefficient corresponding to each slip ratio is calculated based on each torque, ground load, and radius of the test piece 10, the slip ratio and the friction are calculated. Can be automatically measure the number of relationships, it is extremely advantageous for measuring the coefficient of friction of the rubber material for tires.

  Since the apparatus main body 1 is moved using a plurality of wheels 70 that support the apparatus main body 1 and a wheel drive mechanism 71 that can rotate two wheels 70 of each wheel 70 at an arbitrary speed. The apparatus main body 1 can be moved with a simple configuration, which is advantageous in reducing the weight of the apparatus and reducing the manufacturing cost.

  In the present embodiment, the apparatus main body 1 is moved by the wheels 70 and the wheel drive mechanism 71. However, as shown in FIG. 12, a pair provided to extend along the road surface. Rail 100, a plurality of guide members 101 that support the apparatus main body 1 movably along the rails 100, a ball screw and a motor (not shown) that can move the apparatus main body 1 along the rails 100 at an arbitrary speed, and the like. It is also possible to move the apparatus main body 1 along each rail 100. The ball screw and the motor correspond to the main body driving device described in the claims.

Sectional drawing of the friction coefficient measuring apparatus which shows 1st Embodiment in this invention AA line sectional view in FIG. B direction arrow view in FIG. Plan view of friction coefficient measuring device Cross section of torque detector Plan view of control panel Block diagram of friction coefficient measuring device Flow chart showing operation of control unit The side view of the friction coefficient measuring apparatus which shows 2nd Embodiment in this invention Block diagram of friction coefficient measuring device Flow chart showing operation of control unit The side view of the friction coefficient measuring apparatus which shows the modification of 2nd Embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Apparatus main body, 1a ... Lower end surface, 1c ... Window, 10 ... Test piece, 11a ... Spindle, 13 ... 1st support member, 14 ... 2nd support member, 20 ... Drive apparatus, 30 ... Installation load adjustment mechanism, DESCRIPTION OF SYMBOLS 31 ... Adjustment screw, 32 ... Spring, 40 ... Torque detector, 41 ... Strain gauge, 42 ... Antenna, 50 ... Tachometer, 60 ... Control panel, 60a ... Control part, 61 ... Display part, 61a ... Shaft height Display unit, 61b ... Contact load display unit, 61c ... Measurement result display unit, 62 ... Input button, 63 ... Start button, 70 ... Wheel, 71 ... Wheel drive device, 80 ... Speedometer, 100 ... Rail, 101 ... Guide member .

Claims (10)

In a friction coefficient measuring device that measures a friction coefficient between a predetermined material and a road surface,
A device main body provided on the lower end side with a predetermined grounding portion for grounding to the road surface;
A rotatable test piece supported at least in a vertical direction on the apparatus main body so that at least an outer peripheral surface is made of a predetermined material and a rotation axis is arranged substantially horizontally;
A drive for rotating the specimen;
A grounding load adjusting means for grounding the outer peripheral surface of the test piece to the road surface with an arbitrary grounding load in a state where the grounding portion of the apparatus main body is in contact with the road surface;
A torque detector capable of detecting torque applied to the test piece when the outer peripheral surface of the test piece contacts the road surface;
A friction coefficient measuring apparatus comprising: a calculating means for calculating a friction coefficient between the outer peripheral surface of the test piece and the road surface based on the torque, the ground load, and the radius of the test piece. The friction coefficient measuring device according to claim 1, wherein the driving device is configured to be able to arbitrarily set the rotation speed of the test piece. A tachometer capable of detecting the rotation speed of the test piece;
Rotational speed control means for rotating the test piece so that the rotational speed gradually increases at an arbitrary acceleration by a driving device;
Detection control means for detecting the torque by the torque detector and detecting the rotation speed of the test piece by a tachometer a predetermined number of times while the test piece is rotating so as to gradually increase the rotation speed;
A slip speed calculating means for calculating the slip speed of the test piece according to each rotation speed detected by the tachometer,
The friction coefficient measuring device according to claim 2, wherein the calculating means is configured to calculate a friction coefficient corresponding to each sliding speed based on each torque detected by a torque detector. In a friction coefficient measuring device that measures a friction coefficient between a predetermined material and a road surface,
The device body;
A main body moving means capable of moving at an arbitrary speed in a predetermined direction while disposing the apparatus main body at a predetermined height position with respect to the road surface;
A rotatable test piece supported at the apparatus body so as to be movable in the vertical direction so that at least the outer peripheral surface is made of a predetermined material and the rotation axis is arranged substantially horizontally and substantially perpendicular to the movement direction of the apparatus body; ,
A drive for rotating the specimen;
A grounding load adjusting means for grounding the outer peripheral surface of the test piece to the road surface with an arbitrary grounding load in a state where the apparatus main body is disposed at a predetermined height position with respect to the road surface;
A torque detector capable of detecting torque applied to the test piece when the outer peripheral surface of the test piece contacts the road surface;
A friction coefficient measuring apparatus comprising: a calculating means for calculating a friction coefficient between the outer peripheral surface of the test piece and the road surface based on the torque, the ground load, and the radius of the test piece. The friction coefficient measuring device according to claim 4, wherein the driving device is configured to be able to arbitrarily set the rotation speed of the test piece. A speedometer capable of detecting the moving speed of the apparatus body;
Rotational speed control means for rotating the test piece at a predetermined speed by a driving device;
A moving speed control means for moving the apparatus main body so that the speed gradually increases at an arbitrary acceleration by the main body moving means;
While the test piece rotates at a predetermined rotation speed and the apparatus main body moves so as to gradually increase the speed, the torque detection by the torque detector and the speed of the apparatus main body by the speedometer are detected a predetermined number of times. Detection control means to be performed;
A slip ratio calculating means for calculating the slip ratio of the test piece according to each speed detected by the speedometer,
The friction coefficient measuring apparatus according to claim 5, wherein the calculating means is configured to calculate a friction coefficient corresponding to each slip ratio based on each torque detected by a torque detector. The said main body moving means is comprised from the several wheel which can rotate which supports an apparatus main body, and the wheel drive device which can rotate at least 1 wheel at arbitrary speeds among each wheel. 5. The friction coefficient measuring device according to 5 or 6. The main body moving means includes a rail provided so as to extend along the road surface, a guide member that supports the apparatus main body so as to be movable along the rail, and a main body capable of moving the apparatus main body at any speed along the rail. The friction coefficient measuring device according to claim 4, wherein the friction coefficient measuring device is constituted by a driving device. The friction coefficient measuring device according to claim 1, further comprising a display unit that displays a calculation result of the friction coefficient. The friction coefficient measuring device according to claim 1, further comprising: a recording device that records a calculation result of the friction coefficient.

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