JP2000310591A - Static friction tester and method for measuring coefficient of static friction - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a static friction tester high in measuring accuracy, capable of being made compact and enabling automatic measurement and a method for measuring the coefficient of static friction. SOLUTION: A static friction tester has a slider (inclined stand) and a sled (movable stand) between which a plurality of wires are provided under tension and is equipped with a motor and a speed reducing mechanism for gradually inclining the slider, a rotation detecting sensor for detecting the number of rotations of the motor, a position detecting sensor for detecting the position of the sled beginning to slide, a personal computer for inputting the signal from the rotation detecting sensor and the signal from the position detecting sensor to operationally process them to calculate the angle of inclination and/or tanθ of the slider when the sled begins to slide, a power control circuit for controlling the motor by the command from the personal computer and an operation panel for displaying the operational processing result of the personal computer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tester for measuring a static friction coefficient of a magnet wire or a cable (hereinafter, referred to as a wire) and a method of measuring a static friction coefficient.
More specifically, the present invention relates to a static friction tester capable of automatic measurement and a method for automatically measuring a static friction coefficient.

[0002]

2. Description of the Related Art A conventional manual static friction tester will be described with reference to FIG. 2A is a perspective view of a manual static friction tester, FIG. 2B is a schematic view showing a slider having four wires stretched, and FIG. 2C is a schematic diagram showing four wires. It is the schematic which shows the sled which stretched. A conventional manual static friction tester has a structure as shown in FIG.
A slider (21), a handle (23) and a gear (2) for manually moving the slider (21) from a horizontal state to an inclined state.
4). The slider (21), the handle (23), and the like are held by a support (26) of a base (25). At one end of the base (25), a scale plate (27) having a scale (e) whose angle is indicated by tan θ is provided. A pointer (f) is attached to the tip of the slider (21).

When performing a static friction test, first, as shown in FIG.
A wire (w) is stretched and fixed with screws (g). Further, as shown in FIG. 5C, four wires (w) are also stretched over the sled (22) and fixed with screws (g).
Next, the sled (22) on which the four wires are stretched is placed at a predetermined position so that the wire of the slider (21) and the wire of the sled (22) are orthogonal to each other, and the handle (23) is manually operated. Rotate with
Slowly tilt the slider (21) from the horizontal position to
The angle at which 2) starts to slide was read by the tan θ scale (e) indicated by the pointer (f).

[0004]

However, in the conventional static friction tester (30), the slider (21) is manually tilted by the handle (23). Changed by
There is a problem that the measured values vary. In addition, there is a problem that the measurement error is large because the tan θ scale (e) must be checked at the moment when the sled (22) starts sliding.
Also, since the tan θ scale is used, the resolution of the inclination angle is poor, and the length of the slider (21) is increased (for example, about 0.9
0m), there is a disadvantage that the measurement accuracy cannot be obtained.
Therefore, the test device could not be made compact. In addition, the measurement had to be performed manually by eye measurement, and the measurement could not be performed automatically. SUMMARY OF THE INVENTION The present invention has been made to solve the above-described various problems of the related art, and has as its object to provide a static friction tester that has high measurement accuracy, can be compact, and can perform automatic measurement.

[0005]

According to a first aspect of the present invention, there is provided a tester for measuring the coefficient of static friction of a magnet wire or a cable (hereinafter, referred to as a wire). A slider (tilt base) that can be moved to an inclined state from above, and a sled (movable base) that is stretched so that a plurality of the wires intersect with the wires on the slider, and the sled is placed on the horizontal slider. It is a static friction tester that can measure a tilt angle (hereinafter, abbreviated as an angle) when a sled starts to slide by being placed and gradually inclining the slider. A motor and a deceleration mechanism for gradually inclining, a rotation detection sensor for detecting the number of rotations of the motor, a position detection sensor for detecting the position of the sled that has begun to slide, and the rotation detection sensor. A personal computer that calculates the angle and / or tan θ (static friction coefficient) when the sled starts to slide by inputting a signal from the sensor and a signal from the position detection sensor to perform arithmetic processing, and a motor based on a command from the personal computer. The static friction tester comprises a power system control circuit for controlling the operation of the personal computer, and an operation panel on which the results of the arithmetic processing of the personal computer are displayed and various switches are provided.

In the static friction tester according to the first aspect, the slider can be automatically and gradually inclined by using a motor, a speed reduction mechanism, for example, a speed reducer, a gear, or the like. Since the resolution is low only with the gear, the resolution can be increased by using a reduction gear together. Further, the position of the sled that has begun to slide can be detected by a position detection sensor, for example, a proximity switch, and the motor and the slider can be stopped. Also, the rotation speed of the motor is detected by a rotation detection sensor, for example, a proximity switch, and a signal from the rotation detection sensor is input by a personal computer to perform arithmetic processing, and the angle and / or tan of the slider when the sled starts to slide. θ (static friction coefficient) is automatically calculated.
The power system control circuit controls the power of the motor in accordance with a command from the personal computer. The operation panel displays the results of the arithmetic processing by the personal computer and is provided with various switches. Therefore, in the static friction tester of the present invention, the measurement error of the coefficient of static friction is reduced. Conventionally,
Since the tan θ scale was used, the resolution of the inclination angle was poor, and there was a disadvantage that the measurement accuracy would not be obtained unless the length of the slider was increased.However, in the static friction tester of the present invention, the length of the slider was short. Even with accuracy. Therefore, the tester can be made compact and automatic measurement can be performed.

According to a second aspect, the present invention relates to a method for measuring the coefficient of static friction of the static friction tester according to the first aspect, wherein the slider is gradually tilted by a motor via a speed reduction mechanism. The motor and the slider are stopped by detecting the moment when the sled starts to slide out by the position detection sensor, and the rotation speed of the motor required until the stop is detected by the rotation detection sensor, and the personal computer is taken into consideration in consideration of the reduction ratio of the reduction mechanism. Is a method of measuring a static friction coefficient by calculating an inclination angle and / or tan θ (static friction coefficient) of a slider by performing arithmetic processing.

In the method of measuring a coefficient of static friction according to the second aspect, the inclination angle and / or tan θ of the slider can be automatically calculated from the number of rotations of the motor detected by the rotation detection sensor. Accordingly, the measurement error of the coefficient of static friction is reduced and the accuracy is improved, so that it can be preferably applied to the static friction tester of the first aspect.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a static friction tester and a method for measuring a coefficient of static friction according to the present invention will be described with reference to the drawings. The present invention is not limited to these embodiments. FIG. 1 is a block diagram showing the configuration of the static friction tester of the present invention. 2A and 2B are schematic views showing the structure of the static friction tester of the present invention. FIG. 2A is a front view, FIG. 2B is a side view, and FIG. 2C is a top view (only the upper part of the slider is shown). It is. 3A and 3B are schematic diagrams showing the positional relationship between the sled on the slider and the position detection sensor. FIG. 3A shows a state where the slider is horizontal, and FIG. 3B shows a state where the slider is inclined. FIG. 4 shows the coefficient of static friction (ta) of the present invention.
5 is a schematic diagram for explaining a method of measuring nθ), and shows a method of calculating an angle from the number of rotations of a motor. In these figures, 1 is a slider, 2 is a sled, 3 is a position detection sensor,
4 is a motor, 5 is a speed reducer, 6a is a slider gear, 6b
Is a motor gear, 7 is a rotation detection sensor, 8 is a base, 9 is a column, 10 is an operation panel (power system control circuit and built-in personal computer), and 20 is a static friction tester.

-Embodiment 1- One embodiment of a static friction tester of the present invention will be described with reference to FIGS. Examples of the configuration of the static friction tester (20) of the present invention include a slider (1) having a plurality of wires (W) stretched thereon and movable from a horizontal state to an inclined state, and a plurality of the wires (W). Has a sled (movable table) (2) stretched so as to intersect with the wire (W) on the slider (1),
At the start of measurement, the sled (2) is in the horizontal position
(1) Placed on top. Other configurations include a motor (4) for automatically inclining the slider (1) gradually, a speed reducer (5), a motor gear (6b) and a slider gear (6a), and the motor (4). ), A position detection sensor (3) for detecting the position of the sled (2) that has begun to slide, and the position detection sensor.
(3) and a signal from the rotation detection sensor (7) are input to perform arithmetic processing, and a personal computer (PC) that automatically calculates the angle at which the sled (2) starts to slide, and a motor (4) based on commands from the personal computer ), And an operation panel (10) that displays the results of arithmetic processing by the personal computer and is provided with various switches. In addition,
The slider (1), the motor (4) and the like are held by a base 8 and a support 9. The central axes of the slider (1) and the slider gear (6a) are directly connected.

In the static friction tester (20) of the present invention, the dimensions of the slider (1) are, for example, 90 mm on the short side and 5 mm on the long side.
00 mm. The dimensions of the sled (2) are, for example, 70 mm in length and width. The material of the slider (1) and the sled (2) is not particularly limited, but is, for example, aluminum (however, the surface on which the wire is stretched is glass-coated with a thickness of 5 mm). The weight of the sled (2) depends on the diameter of the wire, for example, 100 g for less than 0.45 mm and 20 g for 0.45 mm or more.
0 g is specified. It has been confirmed that there is no significant difference in the measurement results depending on the weight of the sled (2), but the larger the wire diameter, the stronger the wire habit. The distance between the wires stretched over the slider (1) and the sled (2) is, for example, 15 mm. Although the number of wires to be stretched is not particularly limited, a state in which the sled (2) can be stably mounted is preferable. Further, the position detection sensor
(3) and the rotation detection sensor (7) are commercially available, and for example, a proximity sensor manufactured by OMRON Corporation can be used.

Embodiment 2 The operation and operation of the static friction tester (20) of the present invention are shown in FIG.
This will be described with reference to FIGS. First, as shown in FIG. 2C, four wires (w) are stretched over the slider (1) and fixed with screws (g). Although not particularly shown in FIG. 2, four wires are also stretched over the sled (2) in the same manner as in the conventional FIG. 5 (b) and fixed by screws. Next, the slider (1) is automatically positioned in a horizontal state (using a horizontal level). Next, the position detection sensor (3) is installed at a predetermined position on the slider (1). Next, as shown in FIG. 3 (a), the sled (2) is placed at the last position on the slider (1) which is not detected by the position detecting sensor (3).

Next, the motor speed is set on the touch panel of the operation panel (10), and the start switch is pressed to operate the motor (4). Then the rotation of the motor (4) is reduced
(5) A slider directly connected to the central axis of the gear (6a) via the motor gear (6b) and the slider gear (6a).
(1) Gradually tilt. At this time, the number of rotations of the motor (4) is detected by a rotation detection sensor (7) and inputted to a personal computer for calculation. When the slider (1) is further inclined, the sled (2) starts to slide at a certain angle as shown in FIG. 3 (b). At this time, the position detection sensor (3) senses the operation of the sled (2) and stops the motor (4) and the slider (1) by a personal computer and a power system control circuit.
The rotation speed of the motor (4) at the time when the slider (1) stops is calculated by a personal computer to calculate tan θ and angle, and the tan θ and angle are calculated as a static friction coefficient on the touch panel of the operation panel (10). Is displayed. After the measurement of the coefficient of static friction is completed, the slider (1) operates in reverse by the angle of inclination by the personal computer and the power system control circuit, and automatically returns to the origin (horizontal state).

Embodiment 3 An embodiment of the method for measuring the coefficient of static friction of the present invention will be described with reference to FIG. In the static friction tester (20) of the present invention, first, when the motor (4) makes one rotation, the speed is reduced to 1/1800 rotation by the speed reducer (5). Furthermore, the motor gear (6b) and the slider gear (6) directly connected to the rotation shaft of the reduction gear (5)
Since the gear ratio of (a) is set to 1: 2, the slider gear (6a) operates only 1/3600 rotation. At this time,
Since the slider gear (6a) is directly connected to the slider (1), the slider (1) operates (inclines) by 0.1 degree with respect to the angle of one rotation of the motor, that is, 360 degrees. Therefore, the rotation speed of the motor (4) at the time when the slider (1) stops is detected by the rotation detection sensor (7) and is processed by a personal computer. However, the rotation speed (until the slider stops) × The angle is calculated at 0.1 degree, and tan θ is calculated. Then, this measurement result is displayed on the touch panel of the operation panel (10).

-Measurement of Coefficient of Static Friction- Using an apparatus for measuring static friction of the present invention and in accordance with the method for measuring a coefficient of static friction of the present invention, an enameled wire (1-SF.BR 0.
The results of measuring the static friction coefficient (15 mm) are shown in Table 1 below. The sled (2) used was 100 g and 200 g.

[0016]

[Table 1]

As is clear from Table 1 above, the measured value of the coefficient of static friction measured by the static friction tester and the measuring method of the present invention is stable without large variation. Also, it can be seen that the measurement result hardly changes even if the weight of the sled differs.

[0018]

According to the static friction tester of the present invention, the coefficient of static friction can be calculated from the number of rotations of the motor.
The measurement error of the coefficient of static friction was reduced. Conventionally, ta
The resolution of the tilt angle is poor due to the use of the nθ scale,
There was a drawback that the measurement accuracy could not be obtained unless the length of the slider was increased. However, in the static friction tester of the present invention, the accuracy was improved even if the length of the slider was short due to the difference in the measurement method. Therefore, the tester can be made compact, the accuracy can be improved, and automatic measurement can be performed. Therefore, the effect of contributing to industry is extremely large.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an example of a configuration of a static friction tester of the present invention.

FIG. 2 is a schematic view showing an example of the structure of a static friction tester of the present invention, wherein FIG. 2 (a) is a front view, FIG. 2 (b) is a side view, and FIG. Only shown).

3A and 3B are schematic diagrams showing an example of a positional relationship between a sled on a slider and a position detection sensor. FIG. 3A shows a state in which the slider is horizontal, and FIG. 3B shows a state in which the slider is inclined. Show.

FIG. 4 is a schematic diagram for explaining an example of a method of measuring a static friction coefficient according to the present invention, and shows a method of calculating tan θ and an angle from a motor rotation speed.

FIG. 5 is a schematic view showing the structure of a conventional manual-type static friction tester. FIG. 5A is a perspective view of the static friction tester, and FIG.
Is a schematic diagram showing a slider with four wires stretched, and FIG. 3C is a schematic diagram showing a sled with four wires stretched.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Slider 2 Sled 3 Position detection sensor 4 Motor 5 Reduction gear 6a Slider gear 6b Motor gear 7 Rotation detection sensor 8 Base 9 Post 10 Operation panel 20 Static friction tester

Claims (2)

[Claims] 1. A tester for measuring a static friction coefficient of a magnet wire or a cable (hereinafter, referred to as a wire). A plurality of wires have a sled (movable table) stretched so as to intersect with the wires on the slider, and the sled is placed on the horizontal slider, and the slider is gradually inclined, A static friction tester capable of measuring an inclination angle when a sled starts to slide, a motor and a deceleration mechanism for automatically inclining the slider gradually, and a rotation detecting a rotation speed of the motor. A detection sensor, a position detection sensor for detecting the position of the sled that has begun to slide, and a signal from the rotation detection sensor and a signal from the position detection sensor are input to perform arithmetic processing. It was carried out, the inclination angle and / or ta when the sled began Suberidashi
n A personal computer for calculating θ (static friction coefficient), and power (electric power) for controlling the motor based on a command from the personal computer
A static friction tester, comprising: a system control circuit; and an operation panel for displaying a result of arithmetic processing of the personal computer and provided with various switches. 2. The method for measuring a static friction coefficient of a static friction tester according to claim 1, wherein the slider is gradually inclined by a motor via a speed reduction mechanism, and the moment when the sled on the slider starts to slide is determined. While detecting with a position detection sensor to stop the motor and the slider,
The number of rotations of the motor required until the stop is detected by the rotation detection sensor, and the processing is performed by a personal computer in consideration of the speed reduction ratio of the speed reduction mechanism.
n A method for measuring a coefficient of static friction, comprising calculating a coefficient of static friction (θ).