JPH1183471A - Method and apparatus for measuring surface roughness of road surface - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure the dynamic friction coefficient and the roughness at a single position by successively measuring the position with a dynamic friction coefficient- measuring apparatus and a roughness-measuring apparatus having a laser displacement meter, which is rotated in the same track as a rubber body for measurement. SOLUTION: The dynamic friction coefficient-measuring apparatus is connected by a driving disk having a high inertia force by a spring balance and rotates the disk having a rubber body for measurement to measure the dynamic friction coefficient from the displacement of the spring balance. A laser head 51 of a laser displacement meter of a roughness-measuring apparatus A is so set as to rotate in the same track as that of the rubber body for measurement of the dynamic friction coefficient- measuring apparatus by a D.C. motor 39 while using a reduction gear 38, an output shaft 40, gears 41, 41a, a rotary shaft 45, and a rotary plate 50. In this case, measurement is carried out by installing either one of the dynamic friction coefficient- measuring apparatus and the roughness-measuring apparatus A and then measurement is again carried out by installing the other measurement apparatus in the same measuring position, so that the dynamic friction coefficient and the roughness of the same position can be measured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for measuring roughness at the same position where a dynamic friction coefficient of a road surface is measured.

[0002]

2. Description of the Related Art Conventionally, various techniques for measuring the roughness of a road surface and the coefficient of kinetic friction (μ) are known, and those measuring devices are towed by a trailer or the like to separately measure the roughness and the coefficient of kinetic friction. . However, the value of the dynamic friction coefficient generally has a large deviation depending on the measuring device, and in order to unify the deviation, it has been demanded to obtain a relationship with the road surface roughness and thereby obtain an IFI (International Friction Index) value.

For this purpose, it is necessary to measure the roughness and the coefficient of dynamic friction at the same location on the road surface, and it is very difficult to measure two values at the same location.

[0004] Regarding the measurement of the dynamic friction coefficient, the present applicant has developed an easy-to-handle dynamic friction coefficient measuring apparatus in Japanese Patent Publication No. 3-10062. In order to better understand the present invention, an outline of a known dynamic friction coefficient measuring device will be described with reference to FIGS. In the dynamic friction coefficient measuring device indicated by reference numeral B as a whole, the friction measuring unit 1 is rotated by the driving unit 2. The drive unit 2 is supported by a holder 3 fixed on an underframe 4, and can be moved up and down together with the friction measurement unit 1 by moving a lever 5 up and down. At four corners of the bottom surface of the underframe 4, rubber seats 6 are provided for stably setting the entire apparatus on a surface to be measured, for example, a road surface. The friction measuring section 1 has a drive disk 8 having a large inertia fixed to a drive shaft 7.
A slip ring 9 is fixed to the upper surface of the. Also,
The drive shaft 7 has a disk 10 with a small inertia below the drive disk 8.
Is rotatably mounted. On the lower surface of the disk 10 are three rubber bodies 11 for measuring the coefficient of friction on a concentric circle with the drive shaft 7.
Is fixed. The drive disk 8 and the disk 10 are connected by a spring balance 12, and therefore the disk 10
Is adapted to rotate together with the driving disk 8 via a spring balance 12. A displacement gauge 13 is mounted between the driving disk 8 and the disk 10 for measuring the amount of displacement of the spring balance 12 and converting it into an electrical amount when a load is applied to the disk 10. Further, a roller 14 is attached to the lower surface of the driving disk 8 to apply a vertical load to the rubber body 11 of the disk 10. The drive unit 2 has a magnet motor 15,
The drive shaft 7 is rotated by the magnet motor 15 via the coupler 16. The magnet motor 15 is supported in the case of the drive unit 2 by a motor support 17. The drive shaft 7 is supported by a bearing bracket 18 attached to the lower surface of the case of the drive unit 2, and the drive unit 2 and the friction measurement unit 1 move up and down integrally via the drive shaft 7. . During the rotation of the friction measuring unit 1, the electric output generated by the displacement meter 13 is taken out of the slip ring 9 via the brush 19.
The brush 19 is attached to a brush holder 20,
And is fixed to the lower surface of the case of the drive unit 2 via the.

In operation, first, the apparatus is installed on a surface to be measured, for example, on a road surface, and in this state, the lever 5 is lowered, and the friction measuring unit 1 and the driving unit 2 are lifted off the road surface. When the magnet motor 15 rotates, the drive shaft 7 rotates, and the friction measuring unit 1 rotates. When the rotation speed exceeds the measurement speed, the magnet motor 15 is turned off, and at the same time, the lever 5 is released slowly. When the rubber body 11 comes into contact with the road surface, a frictional force acts to stop the disk 10, but the drive disk 8 tries to keep rotating by inertia. Therefore, a twist is generated between the driving disk 8 and the disk 10, and this force displaces the spring balance 12, and the amount of the displacement is measured by the displacement meter 13. Then, the output is recorded as the Y component of the XY recorder, and the frictional force applied to the rubber body 11 is transmitted to the drive disk 8 via the spring balance 12, so that
The driving disk 8 is gradually decelerated to a stop. During that time, the motor 15 rotates together via the drive shaft 7, so that an electromotive force is generated, and this electromotive force may be recorded as the X component of the XY recorder 29.

On the other hand, a small laser displacement type which is measured by triangulation using a light emitting element and a light receiving element which emit laser light is known.

Therefore, as a result of various studies, the present inventor has used a rubber body of the rotating dynamic friction coefficient measuring device, that is, a laser displacement meter that rotates at the same position (radius) as the measuring position (measuring radius) of the dynamic friction coefficient. It has been found that the dynamic friction coefficient and the roughness can be measured at the same position by using the roughness measuring device.

[0008]

SUMMARY OF THE INVENTION It is, therefore, a primary object of the present invention to provide a method for measuring dynamic friction coefficient and surface roughness at the same location.

Another object of the present invention is to provide a road surface roughness measuring device for implementing the above method.

Another object of the present invention is to provide an apparatus for measuring the roughness of a road surface which can be easily handled and easily measured.

[0011]

According to the method of the present invention,
Prepare a kinetic friction coefficient measuring device for measuring a kinetic friction coefficient by displacement of a spring balance by rotating a driving disk having a large inertial force and a disk having a rubber body for measurement connected by a spring balance, and a rubber body for the measurement. Prepare a roughness measuring device with a laser displacement meter that rotates on the same trajectory, install and measure one of those measuring devices, and on the other hand the same position as the measured position on the other measuring device The other measuring device is installed so as to measure the dynamic friction coefficient and the roughness at the same position.

According to the apparatus of the present invention, a frame having legs installed on a road surface is provided, and a motor with a gear reducer is provided on the frame, and is integrated with an output shaft of the gear reducer. An encoder and a rotary plate are provided on the rotating shaft that rotates, and the rotary plate is provided with a laser displacement type. The output of this laser displacement meter is sampled by a pulse signal from the encoder, and the sampled signal is obtained. Is used to determine the roughness of the circular locus.

As described above, according to the present invention, if the roughness measuring device is first installed to measure the roughness of the road surface, and then the dynamic friction coefficient measuring device is installed at the same position, both of them rotate on the same locus. Therefore, the dynamic friction coefficient at the same position can be measured. Therefore, the relationship between the roughness of the road surface and the coefficient of dynamic friction can be obtained.

The roughness measuring apparatus according to the present invention is rich in portability itself, and is easy to install and measure. Since the road surface is measured with a circular locus, for example, if the circular locus is divided into eight equal parts and the average of the roughness for each sampling length is obtained, a single measurement can be performed in each direction (traveling direction, perpendicular to the traveling direction). (A direction at an angle of 45 degrees with respect to the direction and the running direction).

If the dynamic friction coefficient is measured first when the present invention is carried out, rubber may adhere to the road surface or the road surface may be wetted. Therefore, it is preferable to measure the roughness first.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. First, an example of a roughness measuring device embodying the present invention will be described with reference to FIGS.

1 and 2, a roughness measuring apparatus embodying the present invention, which is generally designated by reference numeral A, includes a rectangular frame 32 having legs 31 for installation on a road surface G. Is made of an elastic material such as rubber. At the center of the frame 32, a support plate 34, which is supported by a column 33 and spans both sides, is fixed with screws 35. Ribs R are provided upright on both edges of the support plate 34.

A first substrate 37 is mounted on the support plate 34 via first supporting legs 36, and a DC motor 39 with a gear reducer 38 is mounted on the first substrate 37. The gear reducer 38 is, for example, a 1/200 reducer, and a first gear 41 is attached to an output shaft 40 so as to rotate integrally.

On the other hand, a second board 43 is mounted on the second support leg 42, and an encoder 44 is mounted on the board 43. A second gear 41a meshing with the first gear 41 is fixed to a rotation shaft 45 of the encoder 44. The rotating shaft 45 is rotatably supported by bearings 47 and 48 supported by a bearing bracket 46 fixed below the support plate 34, and a lower end thereof is provided with a rotating plate 50 via a bracket 49. I have.

The rotary plate 50 is provided with a laser head 51 of a laser displacement meter. This laser head 51
Is a laser beam L1 radiated from a light emitting element is diffusely reflected on a road surface G, and a part L2 of the reflected light is received by a light receiving element.
The distance to is calculated.

Therefore, when the DC motor 39 is rotated, the rotational speed is reduced by the gear reducer 38, and the rotational force is transmitted to the rotary shaft 45 via the output shaft 40, the first gear 41, and the second gear 41a. Is transmitted. The rotation of the rotating shaft 45 causes the encoder 44 and the rotating plate 50 to rotate.
As a result, the laser head 51 detects the roughness along the circular locus P in FIG.

By designing the circular locus P and the circular locus of the rubber plate 11 shown in FIG. B at the same position, the same friction coefficient and surface roughness at the same position can be known.

FIG. 3 is a block diagram for measuring the surface roughness according to the present invention. The signal of the light receiving element of the laser head 51 is input to the amplifier unit 60 and converted into a voltage proportional to the distance to the road surface. . And the A / D converter 61
Is input to On the other hand, the sampling signal from the encoder 44 is also input to the A / D converter 61, and the digital signal sampled by the sampling signal is stored in the memory of the personal computer 62. From this stored data, the M.P. P. D. (Mea
n Profile Depth) is calculated. FIG.
Shows an example of this measurement result. In FIG. 4, the horizontal axis indicates the length (the length of the arc of the locus P), and the symbol L indicates the sampling length. The vertical axis indicates the distance from the laser head 51. Symbol E indicates the light emitting position of the laser head, and symbol H indicates the level of the road surface G.

In this way, the personal computer 62 can
A regression line H1 is calculated from a value obtained by measuring a road surface unevenness state F with a laser displacement meter every 1 mm for a sampling length L of 00 mm, and the highest mountain level H2 is calculated from the H1.
Is subtracted to calculate the MPD. The position H of the leg is such that all irregularities within a measurement range M (for example, 30 mm) of the laser displacement meter of the laser head 51 are included.

As described above, according to the present invention, the roughness of the road surface can be easily obtained, and the roughness in each direction can be obtained by one operation. By combining with a rotating plate type dynamic friction coefficient measuring device, the road surface roughness and the dynamic friction coefficient at the same position and in the same direction can be obtained, which is effective in studying the slip of tires of automobiles and aircraft.

[Brief description of the drawings]

FIG. 1 is a side view of a road surface roughness measuring device embodying the present invention.

FIG. 2 is a plan view of FIG. 1;

FIG. 3 is a block diagram of a roughness measuring device embodying the present invention.

FIG. 4 is an explanatory diagram showing an example of roughness measured according to the present invention.

FIG. 5 is a plan view of a known dynamic friction coefficient measuring device.

FIG. 6 is a side view of FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Friction measuring part 2 ... Driving part 3 ... Holder 4 ... Underframe 5 ... Lever 6 ... Rubber seat 7 ... Driving shaft 8 ... Driving disk 9 ...・ Slip ring 10 ・ ・ ・ Disc 11 ・ ・ ・ Rubber body for friction coefficient measurement 12 ・ ・ ・ Spring balance 13 ・ ・ ・ Displacement gauge 14 ・ ・ ・ Roller 15 ・ ・ ・ Magnet motor 16 ・ ・ ・ Coupler 17 ・ ・・ Motor column 18 ・ ・ ・ Bearing bracket 19 ・ ・ ・ Brush 20 ・ ・ ・ Brush holder 21 ・ ・ ・ Column 31 ・ ・ ・ Leg 32 ・ ・ ・ Frame 33 ・ ・ ・ Column 34 ・ ・ ・ Support plate 35 ・ ・Screw 36 First leg 37 First substrate 38 Gear reducer 39 DC motor 40 Output shaft 41 First gear 41a Second gear 42 ... 2nd support column 43 ... 2nd board 44 ... Encoder 4 ... Rotating shaft 46 ... Brackets 47 and 48 ... Bearing 49 ... Bracket 50 ... Rotating plate 51 ... Laser head 60 ... Amplifier unit 61 ... A / D converter 62・ ・ ・ PC A ・ ・ ・ Roughness measuring device B ・ ・ ・ Dynamic friction counting measuring device

Claims (2)

[Claims] 1. A dynamic friction coefficient measuring device for measuring a dynamic friction coefficient by displacement of a spring balance by rotating a driving disk having a large inertial force and a disk connected with a spring balance and having a rubber body for measurement is prepared. Prepare a roughness measuring device with a laser displacement meter that rotates on the same trajectory as the measuring rubber body, install and measure one of those measuring devices, and on the other hand, determine the same position as the measured position Install the other measuring device to measure with the other measuring device,
A method for measuring the roughness of a road surface, comprising measuring a dynamic friction coefficient and a roughness at the same position. 2. A frame having legs mounted on a road surface, a motor provided with a gear reducer is provided on the frame, and a rotating shaft which rotates integrally with an output shaft of the gear reducer is provided on a frame. An encoder and a rotary plate are provided, and the rotary plate is provided with a laser displacement meter. The output of the laser displacement meter is sampled with a pulse signal from the encoder, and the sampled signal is used to roughly describe an arc-shaped trajectory. A road surface roughness measuring device for determining the roughness.