JP2003028789A - Surface tangent direction resistance force measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface tangent direction resistance force measuring device usable for both a snowy road surface and an icy road surface, capable of measuring the road surface state with a common measure. SOLUTION: A laterally sliding surface plate 22 is supported slidably by a linear motion bearing 20 on a body frame 12 installed on the road surface 14. A plate spring 44 having a stuck strain gage is mounted on the laterally sliding surface plate 22, and a load pedestal 48 for loading a heavy weight 50 through a linear motion bearing 46 is supported vertically slidably on the plate spring 44. When a test piece 58 is fixed on the under side of the load pedestal 48 and the laterally sliding surface plate 22 is slid, the test piece 58 to which the load is applied is pressed on the road surface 14 and slid. When the test piece 58 is slid, the plate spring 44 is deformed and the resistance of the strain gage is changed, and thereby a resistance force when test piece 58 is moved can be acquired.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface tangential resistance measuring device, and more particularly to a portable surface tangential resistance measuring device.

[0002]

2. Description of the Related Art For example, in the development of a studless tire or the like, there are cases where the condition of a snowy road surface is measured.

It is known that the tire performance on an icy road surface is greatly affected by the dryness and humidity of the surface.

Further, it is known that the tire performance on a snowy road surface is affected by the strength of the snow layer and the dryness and humidity of the surface.

Furthermore, it is known that tire performance is affected by road surface irregularities, both in ice and snow.

Therefore, it has been found that the quantification of the road surface of ice and snow is evaluated by a comprehensive evaluation method of the dryness and wetness of the surface, the strength of the road surface layer, and the unevenness of the road surface.

However, conventionally, there is no dedicated measuring instrument for measuring the condition of the ice road surface, and it is general to measure the ice surface temperature on the ice road surface.

Further, as a measuring instrument for measuring the condition of the snow road surface, for example, a compaction tester (US Smithe
res CTI Compaction Gauge), Kinoshita hardness meter (developed by Seiichi Kinoshita, utility model), Ramsonde (ram hardness meter)
Etc.

[0009] In each of these, a heavy weight having a certain weight is allowed to fall freely on a snowy road surface, and its breaking strength is expressed by its own quantitative value.

In addition, the snow bulk density, the moisture content, the electric resistance value, etc. are used in the snow condition and the component measurement.

[0011]

However, heretofore, there has been no measuring instrument which can be used for both a snowy road surface and an icy road surface and can measure the road surface condition with a common measure.

In view of the above facts, it is an object of the present invention to provide a surface tangential resistance force measuring device which can be used for both snow road surfaces and ice road surfaces and can measure road surface conditions with a common measure. .

[0013]

A surface tangential resistance force measuring device according to claim 1 comprises a main body which can be installed on a road surface, and a test piece which is provided on the main body and which is attached to a mounting portion. A moving member that can move along the road surface in a state of being brought into contact with the road surface by a load, a driving unit that moves the moving member, and the driving unit that makes the test piece contact the road surface with a predetermined load. A sensor for measuring resistance when moving by means.

Next, in the surface tangential resistance measuring device according to the first aspect, a test piece (for example, a part of a tread of a tire) is attached to the mounting portion of the moving member, and the main body is set on the road surface. .

When the moving member is moved by the driving means, the test piece slides while being pressed against the road surface with a constant load.

Since there is friction between the test piece and the road surface,
Resistance (force) is applied when moving the test piece.

The resistance when the test piece is moved by the driving means is
Measured by a sensor.

Since the resistance is related to the friction coefficient between the test piece and the road surface, the friction between the test piece and the road surface depends on the load applied to the test piece and the magnitude of the resistance measured by the sensor. You can also know the coefficient.

According to a second aspect of the present invention, in the surface tangential resistance force measuring device according to the first aspect, there is provided a display device which is connected to the sensor and displays the value of the resistance force measured by the sensor. It is characterized by having a control device provided.

Next, the operation of the surface tangential resistance force measuring device according to the second aspect will be described.

In the surface tangential resistance force measuring device according to the second aspect, the value of the resistance measured by the sensor is displayed on the display device.

According to a third aspect of the present invention, in the surface tangential resistance force measuring device according to the second aspect, the control device displays an average resistance force when the test piece support moving member is moved by a predetermined distance. It is characterized by calculating a value.

Next, the operation of the surface tangential resistance force measuring device according to the third aspect will be described.

In the surface tangential resistance force measuring device according to the third aspect, the control device calculates the average value of the resistance force when the moving member moves the fixed distance.

The average value of the resistance force is displayed on the display device.

According to a fourth aspect of the present invention, in the surface tangential resistance force measuring device according to any one of the first to third aspects, the sensor is a strain for measuring strain generated in the moving means. It is characterized by having a gauge.

Next, the operation of the surface tangential resistance force measuring device according to the fourth aspect will be described.

If resistance (force) is applied when moving the test piece, a part of the moving means is slightly deformed (bending deformation, etc.). Therefore, by attaching a strain gauge to this deformed portion, The resistance (force) acting on the moving means can be known by the change in the resistance of the strain gauge.

According to a fifth aspect of the present invention, in the surface tangential resistance force measuring device according to any one of the second to fourth aspects, the control device comprises the pressing force of the test piece and the resistance. It is characterized in that the coefficient of friction is obtained from the force and the display device displays the value of the coefficient of friction.

Next, the operation of the surface tangential resistance force measuring device according to the fifth aspect will be described.

In the surface tangential resistance force measuring device according to the fifth aspect, the control device obtains the friction coefficient from the pressing force and the resistance force of the test piece. Then, the calculated friction coefficient value is displayed on the display device.

[0032]

BEST MODE FOR CARRYING OUT THE INVENTION A surface tangential resistance force measuring device according to an embodiment of the present invention will be described in detail below with reference to the drawings.

1 to 5 show a surface tangential force measuring device 10 installed on a road surface 14.

The surface tangential resistance force measuring device 10 comprises a frame-shaped main body frame 12.

Posts 16 are fixed to the four corners of the lower surface of the main body frame 12, respectively.

A leg (so-called adjuster) 18 with a height adjusting screw is attached to the lower end of the column 16.

On the upper surface of the body frame 12, a lateral slide surface plate 22 is slidably supported by the linear motion bearing 20 along the longitudinal direction of the body frame 12.

Guide rails 20A constituting the linear motion bearing 20 are fixed in parallel to each other on both sides of the upper surface of the main body frame 12 in the width direction.

Two slide blocks 20B are slidably provided on each of the guide rails 20A, and the horizontal slide surface plate 2 is provided on the upper surface of each slide block 20B.
2 is fixed.

A body upper plate 24 is fixed to the upper portion of the body frame 12 via a spacer 26.

Trapezoidal screw supports 28 are attached to both sides of the upper plate 24 of the main body in the longitudinal direction.

A ball bearing 30 is attached to each trapezoidal screw support 28, and a ball screw 32 is rotatably supported by the ball bearing 30.

A nut bracket 36 having a nut 34 screwed into the ball screw 32 is fixed to the upper surface of the lateral slide surface plate 22.

A pulse motor 38 is attached to one end of the main body upper plate 24 in the longitudinal direction.

The ball screw 32 is coaxially connected to the rotary shaft 38A of the pulse motor 38 via a flexible coupling 40.

Therefore, the rotary shaft 38 of the pulse motor 38 is
When A is rotated, the ball screw 32 rotates and the nut 3
The lateral slide surface plate 22 to which No. 4 is attached slides along the guide rail 20A.

An L-shaped mounting plate 42 is fixed to the lower end of the horizontal slide surface plate 22.

The side surface of the plate spring 44 near the upper end is fixed to the side surface of the mounting plate 42.

The leaf spring 44 has a frame shape that is long in the vertical direction.

The linear motion bearing 4 is provided on the lower half of the side surface 44B of the leaf spring 44 opposite to the mounting plate 42.
A guide rail 46A of No. 6 is fixed in the vertical direction via a rail mounting bracket 47.

A substantially L-shaped load pedestal 48 is attached to a slide block 46B slidably provided on the guide rail 46A.

A heavy weight 50 can be placed on the horizontal portion 48A of the load pedestal 48.

A hole 52 that penetrates vertically is formed in the central portion of the horizontal portion 48A.

On the side surface of the horizontal portion 48A, the hole 5 is provided.
2 is formed with a screw hole 54.

A fixing screw 56 is screwed into the screw hole 54.

The mounting shaft 60 fixed to the test piece 58 can be inserted into the screw hole 54. The mounting shaft 60 is inserted into the hole 52 and the fixing screw 56 is tightened to load the mounting shaft 60 into the load base. It can be fixed to 48.

As shown in FIG. 5, the side surface 44 of the leaf spring 44 is
A strain gauge 62 for measuring the strain of the leaf spring 44 is attached to A and the side surface 44B.

The leaf spring 44 and the strain gauge 62 constitute a so-called load cell.

The strain gauge 62 is connected to the control device 64. The pulse motor 38 described above is also connected to the control device 64.

The control device 64 includes a driver for driving the pulse motor 38, a strain gauge amplifier, a microcomputer, and the like.

The control device 64 can measure the amount of change in the resistance value of the strain gauge 62 and convert it into a resistance force value.

The resistance value is displayed on the display device 66 connected to the control device 64.

The control device 64 includes switches 68 and 70 for designating a moving direction (CW direction or CCW direction in FIG. 1) on the horizontal slide surface plate 22, and a measurement button (pulse motor 38).
Operation switch 72, a measurement button 72 is pressed, a terminal 74 for mainly applying a trigger voltage indicating that the horizontal slide surface plate 22 has started moving, a terminal 76 for connecting a data (memory) recorder, etc., and a switch for switching the display Switch 78
And so on. (Operation) Next, the operation of the surface tangential resistance measuring device 10 of the present embodiment will be described. (1) First, a test piece 58 (a rubber block cut out from a tire tread in this embodiment) is firmly fixed to the tip of the mounting shaft 60 by adhesion or the like. (2) The mounting shaft 60 to which the test piece 58 is fixed is inserted into the hole 52 of the load pedestal 48 from below and fixed using the fixing screw 56.

The horizontal slide surface plate 22 is set in advance at the measurement start position (the end side in the arrow L direction or the end side in the arrow R direction). (3) The surface tangential force measuring device 10 is installed horizontally on the road surface 14. (4) The weight 50 is mounted on the horizontal portion 48A of the load pedestal 48, and a load is applied to the test piece 58 to bring the test piece 58 into pressure contact with the road surface 14.

The test piece 58 includes, in addition to the heavy weight 50,
The load of the test piece 58, the mounting shaft 60, the load pedestal 48, the slide block 46B, etc. will act. In this embodiment, the test piece 58 is pressed against the road surface 14 with a load of 18N.

Further, since the road surface 14 has irregularities, the upper and lower strokes of the slide block 46B are secured so that the test piece 58 moves up and down in accordance with the irregularities.

As a result, the test piece 58 can be pressed against the road surface 14 with a constant load. (5) The measurement button 72 is pressed, the pulse motor 38 is rotated, and the lateral slide surface plate 22 is slid at a constant speed to the end opposite to the start position by a predetermined distance.

As a result, the test piece 58 slides on the road surface 14 for a predetermined distance while being pressed against the road surface 14 with a constant load.

When the test piece 58 slides on the road surface 14, the leaf spring 44 is slightly deformed.

When the leaf spring 44 is deformed (bent), the resistance of the strain gauge 62 changes, but the resistance value of the strain gauge 62 is continuously measured by the controller 64.

The control device 64 calculates the resistance force (unit: N) according to the amount of change in the resistance value, and the display device 66 displays the calculated resistance force value.

By operating the changeover switch 78, the control device 64 calculates the average resistance force when the test piece 58 is moved by a certain distance, and the display device 66 displays the average resistance force. You can also

Even if the road surface 14 has irregularities (waviness), the test piece 58 moves up and down smoothly according to the irregularities, so that the load acting on the test piece 58 can be made constant when sliding for a certain distance. Highly reliable measurement is possible.

Further, the surface tangential resistance force measuring device 10 of the present embodiment has a simple structure, so that it can be miniaturized and lightened, and the actual road surface 14 can be freely measured. .

Further, the surface tangential resistance measuring device 10 of the present embodiment is capable of measuring the surface tangential resistance of a measurement object under the same conditions on any road surface such as snow road, ice road, asphalt, concrete, iron plate and the like. Can be measured.

The surface tangential resistance measuring device 10 of the present embodiment can measure the resistance in the surface tangential direction of the object to be measured, but the load (N) applied to the test piece 58 and the above It is also possible to calculate the friction coefficient from the resistance force (N) thus measured. (Test Example) The results of measuring the friction coefficient of various road surfaces using the surface tangential resistance measuring device 10 of the present invention are shown in Table 1 below.
Described in.

[0077]

[Table 1]

Further, the coefficient of friction on ice of the elastic rubber, the tire rubber 1, the tire rubber 2, and the steel thin plate was measured by changing the temperature of the ice. The measurement result was as shown in the graph of FIG.

The coefficient of friction on ice measured using the surface tangential resistance measuring device 10 of the present invention and the braking distance of the passenger car on the ice (when the tires were locked) were measured at different ice temperatures. . The measurement result was as shown in the graph of FIG. 7.

From the test results, it can be seen that the change in friction coefficient (average value) on ice and the change in braking distance are substantially the same.

Further, the coefficient of friction on ice measured using the surface tangential resistance measuring device 10 of the present invention and the braking distance of the passenger car on the ice (at the time of ABS operation) are respectively indicated by the tire type (A). -D) were changed and it measured. The measurement result is shown in FIG.
Was as shown in the graph.

[0082]

As described above, since the surface tangential resistance force measuring device of the present invention has the above-mentioned structure, the resistance in the surface tangential direction of the object to be measured with respect to various road surfaces such as a snow road surface and an ice road surface. It has an excellent effect that the force can be measured with the same measure.

[Brief description of drawings]

FIG. 1 is a front view of a surface tangential resistance force measuring device according to an embodiment of the present invention.

FIG. 2 is a plan view of the surface tangential resistance force measuring device shown in FIG.

FIG. 3 is a left side view of the surface tangential resistance force measuring device shown in FIG.

4 is a right side view of the surface tangential resistance force measuring device shown in FIG. 1. FIG.

FIG. 5 is an explanatory diagram showing connections between a strain gauge, a motor, and a control device.

FIG. 6 is a graph showing the relationship between ice temperature and friction coefficient in each test piece.

FIG. 7 is a graph showing a relationship between an ice temperature and a friction coefficient, and a relationship between each ice temperature and a braking distance when a tire is locked.

FIG. 8 is a graph showing a time-series friction coefficient of a snow road surface and a tire ABS braking distance measured simultaneously.

[Explanation of symbols]

10 Surface tangential resistance measuring instrument 12 Body frame (body) 16 props (main body) 18 Leg with height adjusting screw (main body) 20 Linear motion bearing (driving means) 22 Horizontal slide surface plate (moving member) 24 Main body upper body (main body) 26 Spacer (main body) 28 Trapezoidal screw support (drive means) 30 ball bearings (drive means) 32 ball screw (drive means) 34 Nut (driving means) 36 Nut bracket (drive means) 38 pulse motor (driving means) 40 Flexible coupling (drive means) 42 Mounting plate (moving member) 44 Leaf spring (moving member) 46 Linear motion bearing (moving member) 48 load base (moving member) 48A Horizontal part (mounting part) 58 test pieces 62 Strain gauge (sensor) 64 control device 66 display

Claims (5)

[Claims] 1. A main body to be placed on a measurement object, and a test piece provided on the main body and attached to a mounting portion, which is movable along the surface of the measurement object while being pressed against the measurement object. A test piece support moving member, a drive unit for moving the test piece support moving member, and a sensor for measuring a resistance force when the test piece support moving member is moved by the drive unit. Surface tangential resistance measuring instrument. 2. The surface tangential resistance force according to claim 1, further comprising a control device that is connected to the sensor and includes a display device that displays a value of the resistance force measured by the sensor. Measuring instrument. 3. The surface tangential resistance force measuring device according to claim 2, wherein the control device calculates an average value of the resistance force when the test piece support moving member is moved by a predetermined distance. . 4. The surface tangential resistance force measuring device according to claim 1, wherein the sensor has a strain gauge for measuring a strain generated in the moving means. . 5. The control device calculates a friction coefficient from the pressing force of the test piece and the resistance force, and the display device displays the value of the friction coefficient. 4. The surface tangential resistance force measuring device according to any one of 4 above.