JP2010249707A - Device and method of measuring dynamic friction coefficient - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device of measuring a dynamic friction coefficient by pulling a linear object, such as a communication cable, at an actual traction speed or a pull speed or more. <P>SOLUTION: The device, which measures the dynamic friction coefficient of the linear object, includes: a linear object fixing means for fixing one end of the linear object; a movable stand which includes a placing guide for placing the linear object and moves on an installation surface; a loading means which includes a loading guide contacting the linear object facing the placing guide of the movable stand and loads the linear object via the loading guide; a traction means which pulls the movable stand by a predetermined distance by a constant traction force in the opposite direction of the linear object fixing means; and a moving time measuring means which measures the moving time since the movable stand starts traction till the movable stand moves by the predetermined distance. The contact surfaces of the placing guide and the loading guide with the linear object are flat. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an apparatus and method for measuring a dynamic friction coefficient of a linear object.

  A standard measurement method has been established as a method for testing the dynamic friction coefficient of plastic films and sheets (for example, see Non-Patent Document 1). JIS 7125: 1999 stipulates a method of measuring a friction coefficient at the time of sliding and sliding when a film-like or sheet-like material is slid on the same material or another material.

In this method, the friction coefficient of a non-sticky plastic film or sheet up to an upper limit thickness of 0.5 mm is measured. For example, a plastic film or sheet requires a square with a contact area of 40 cm ² , and the tensile speed for causing friction is normally defined as 100 mm / min ± 10 mm / min.

JIS 7125: 1999 “Plastic film and sheet-Dynamic friction coefficient test method”

  However, it is difficult to apply the above measurement method to the measurement of the dynamic friction coefficient of a linear object such as a communication cable. That is, it has been clarified that there is a large difference in the coefficient of dynamic friction because the shape is greatly different between a rectangle such as a plastic film or sheet and a linear object such as a communication cable. In addition, there is a difference of about two digits between the pulling speed determined by the standard measurement method and the pulling speed or pulling speed of the communication cable, so the measurement did not reflect the actual situation.

  In order to solve the above problems, the present invention provides an apparatus and method for measuring a dynamic friction coefficient by pulling a linear object such as a communication cable at an actual pulling speed or a pulling speed or at a speed exceeding the pulling speed. Objective.

  To achieve the above object, one end of a linear object is fixed, and a dynamic friction coefficient is calculated by pulling a movable base having a guide with a constant traction force while applying a load to the linear object through the guide. It was decided.

  Specifically, the dynamic friction coefficient measuring device of the present invention is a dynamic friction coefficient measuring device for measuring a dynamic friction coefficient of a linear object, and includes a linear object fixing means for fixing one end of the linear object, and the linear object. A movable table having a mounting guide for mounting an object, movable on the installation surface, and a load guide that contacts the linear object facing the mounting guide of the movable table, and through the load guide A load means for loading the linear object, a traction means for pulling the movable base by a predetermined distance in a direction opposite to the linear object fixing means, and the movable base after starting to pull the movable base. Moving time measuring means for measuring a moving time until the predetermined distance travels, and the contact surfaces of the mounting guide and the load guide with the linear object are flat in shape. To do.

  According to this configuration, the dynamic friction coefficient can be measured by pulling a linear object such as a communication cable having a quadrangular cross section at an actual pulling speed or a pulling speed or at a speed exceeding the pulling speed. Further, the dynamic friction coefficient can be measured from the mounting movement time until the movable table moves by a predetermined distance without measuring the frictional force.

  Furthermore, the dynamic friction coefficient measuring apparatus according to the present invention is such that the movable base starts to pull the movable base while holding the linear object between the mounting guide and the load guide measured by the moving time measuring means. The apparatus further comprises dynamic friction coefficient calculating means for calculating a dynamic friction coefficient of the linear object from a mounting movement time that is a movement time until the distance is moved.

  According to this configuration, the dynamic friction coefficient of the linear object can be automatically calculated from the mounting movement time.

  Further, the dynamic friction coefficient measuring apparatus of the present invention is a movement until the movable base is moved by the predetermined distance while holding the linear object between the mounting guide and the load guide measured by the moving time measuring means. The apparatus further comprises dynamic friction coefficient calculating means for calculating a dynamic friction coefficient of the linear object from a mounting movement time that is time and a dynamic friction coefficient between the movable table and the installation surface when the linear object is not mounted. .

  According to this configuration, even if there is a dynamic friction force between the movable table and the installation surface, the dynamic friction coefficient of the linear object can be calculated.

  Furthermore, the dynamic friction coefficient measuring apparatus of the present invention is a movement time from when the dynamic friction coefficient calculating means starts to pull the movable table without mounting the linear object until the movable table moves by a predetermined distance. A dynamic friction coefficient between the movable table and the installation surface is calculated from a no-load movement time.

  By measuring the no-load moving time, the dynamic friction coefficient between the movable table and the installation surface can be calculated.

  Furthermore, the dynamic friction coefficient measuring device of the present invention is a stop distance from when the dynamic friction coefficient calculating means pulls the movable table by a predetermined distance without mounting the linear object until the movable table stops. A dynamic friction coefficient between the movable table and the installation surface is calculated from a no-load stop distance.

  By measuring the no-load stop distance, the dynamic friction coefficient between the movable platform and the installation surface can be calculated.

  Furthermore, the dynamic friction coefficient measuring device of the present invention is a stop time from when the dynamic friction coefficient calculating means pulls the movable table by a predetermined distance without mounting the linear object until the movable table stops. A dynamic friction coefficient between the movable table and the installation surface is calculated from a no-load stop time.

  By measuring the no-load stop time, the dynamic friction coefficient between the movable table and the installation surface can be calculated.

  Furthermore, the dynamic friction coefficient measuring apparatus of the present invention is characterized in that the traction means has a weight that pulls the movable table and falls from the same height as the predetermined distance.

  According to this configuration, the actual pulling speed or pulling speed can be realized by adjusting the mass of the falling weight or the dropping height.

  Furthermore, the dynamic friction coefficient measuring device of the present invention is characterized in that the material of the contact surface of the mounting guide and the load guide with the linear object is the same as the material of the surface of the linear object.

  According to this configuration, the dynamic friction coefficient of the linear object normalized by the material of the surface of the linear object can be measured.

  Furthermore, the dynamic friction coefficient measuring method of the present invention is a dynamic friction coefficient measuring method for measuring the dynamic friction coefficient of a linear object, wherein one end of the linear object is fixed, the linear object is mounted, and the linear object and The contact surface of the movable table has a flat mounting guide and is movable on the installation surface, and accommodates the linear object facing the mounting guide of the movable table, and is in contact with the linear object. A load guide having a flat surface shape, and a load means for loading the linear object with the load guide, while holding the linear object with a constant traction force in the direction of the other end of the linear object. By pulling the movable base by a predetermined distance, and measuring the mounting movement time, which is the movement time from the time when the movable base starts to move by the predetermined distance, The dynamic friction coefficient is measured.

  According to this method, the dynamic friction coefficient can be measured by pulling a linear object such as a communication cable having a quadrangular cross section at an actual pulling speed or pulling speed or at a speed exceeding the pulling speed. Further, the dynamic friction coefficient can be measured from the mounting movement time until the movable table moves by a predetermined distance without measuring the frictional force.

  In the method for measuring a dynamic friction coefficient of the present invention, the dynamic friction coefficient of the linear object is calculated from the dynamic time of the mounting movement and the dynamic friction coefficient between the movable table and the installation surface when the linear object is not mounted. To do.

  According to this configuration, even if there is a dynamic friction force between the movable table and the installation surface, the dynamic friction coefficient of the linear object can be calculated.

  In the dynamic friction coefficient measuring method of the present invention, the dynamic friction coefficient between the movable base and the installation surface when the linear object is not mounted is the movable base for a predetermined distance with a constant traction force without mounting the linear object. It is calculated by measuring a no-load moving time that is a moving time from when the movable table starts to be moved until the movable table moves by the predetermined distance.

  By measuring the no-load moving time, the dynamic friction coefficient between the movable table and the installation surface can be calculated.

  In the dynamic friction coefficient measuring method of the present invention, the dynamic friction coefficient between the movable base and the installation surface when the linear object is not mounted is obtained by pulling the movable base by a predetermined distance without mounting the linear object. It is calculated by measuring a no-load stop distance that is a stop distance until the movable platform stops.

  By measuring the no-load stop distance, the dynamic friction coefficient between the movable platform and the installation surface can be calculated.

  In the dynamic friction coefficient measuring method of the present invention, the dynamic friction coefficient between the movable base and the installation surface when the linear object is not mounted is obtained by pulling the movable base by a predetermined distance without mounting the linear object. It is calculated by measuring a no-load stop time that is a stop time until the movable platform stops.

  By measuring the no-load stop time, the dynamic friction coefficient between the movable table and the installation surface can be calculated.

  Furthermore, the dynamic friction coefficient measuring method of the present invention is characterized in that the movable table is pulled by a predetermined distance with a constant traction force by dropping a weight for pulling the movable table from the same height as the predetermined distance. And

  According to this method, the actual pulling speed or pulling speed can be realized by adjusting the weight of the falling weight or the dropping height.

  Furthermore, the dynamic friction coefficient measuring method of the present invention is characterized in that the material of the contact surface of the mounting guide and the load guide with the linear object is the same as the material of the surface of the linear object.

  According to this configuration, the dynamic friction coefficient of the linear object normalized by the material of the surface of the linear object can be measured.

  According to the present invention, it is possible to provide an apparatus and method for measuring a dynamic friction coefficient by pulling a linear object such as a communication cable at an actual pulling speed or a pulling speed or at a speed exceeding the pulling speed.

It is a figure which shows the cut surface of the movable stand and load means of the dynamic friction coefficient measuring apparatus which concerns on embodiment of this invention. It is a figure which shows the structure of the dynamic friction coefficient measuring apparatus which concerns on embodiment of this invention. It is a figure which shows the structure of the dynamic friction coefficient measuring apparatus which concerns on embodiment of this invention. It is a figure which shows the structure of the dynamic friction coefficient measuring apparatus which concerns on embodiment of this invention. It is a figure which shows the structure of the dynamic friction coefficient measuring apparatus which concerns on embodiment of this invention.

  Embodiments of the present invention will be described with reference to the accompanying drawings. The embodiments described below are examples of the present invention, and the present invention is not limited to the following embodiments. In the present specification and drawings, the same reference numerals denote the same components.

(First embodiment)
A configuration of a dynamic friction coefficient measuring apparatus according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a cutaway view of the movable table 14 and the load means 15 on which the cable 12 is mounted. In FIG. 1, 11 is an installation surface, 12 is a cable as a linear object, 14 is a movable base movable on the installation surface 11, 15 is a load means for loading the cable 12, 14a is a mounting guide, and 15a is a load guide. , 19 is a load means fixing guide.

  The movable table 14 has a mounting guide 14 a for mounting the cable 12, and is movable on the installation surface 11. The load means 15 has a load guide 15a that faces the mounting guide 14a and contacts the cable 12, and loads the cable 12 via the load guide 15a. The load means fixing guide 19 is fixed to the side surface of the movable table 14 and serves as a guide for fixing the load means 15.

  The contact surfaces of the mounting guide 14a and the load guide 15a with the cable 12 are preferably flat. By making the contact surfaces of the mounting guide 14a and the load guide 15a into such a shape, the mounting guide 14a and the load guide 15a can cause dynamic friction to be evenly generated on the surface of the cable 12. When multiple rectangular cables such as rectangles and squares are laid in the inside of a pipe line, the dynamic friction coefficient is calculated in the same environment as when one of the cables is pulled or pulled out. Can be measured.

  The material of the contact surface of the mounting guide 14a and the load guide 15a with the cable 12 is preferably the same as the material of the surface of the cable 12. If the same material is used, the dynamic friction coefficient can be normalized by measuring the dynamic friction coefficient between the same materials. For example, a plurality of cables having a quadrilateral cross section to be measured can be arranged in the radial direction to form the mounting guide 14a or the load guide 15a.

  The configuration of the dynamic friction coefficient measuring apparatus shown in FIG. 1 is common to the following embodiments.

  The first embodiment of the present invention is a case where the movable base can move on the installation surface with a dynamic friction force sufficiently smaller than the dynamic friction force between the linear object and the mounting guide or the load guide. The configuration of the dynamic friction coefficient measuring apparatus according to the first embodiment of the present invention will be described with reference to FIG. In FIG. 2, 11 is an installation surface, 12 is a cable as a linear object, 13 is a linear object fixing means for fixing one end of the cable 12, 14 is a movable base movable on the installation surface 11, and 15 is a cable 12 A load means 16 for loading the cable 12 is a weight as a traction means for pulling the movable base 14 by a predetermined distance with a constant traction force in a direction opposite to the linear object fixing means 13, and 17 is a weight 16 from the height H. It is a buffer stand that receives when it falls.

In the present embodiment, as shown in FIG. 2, it is a movement time from when the movable table 14 is pulled to start moving the movable table 14 until the movable table 14 moves by a predetermined distance with the cable 12 mounted. to measure the mounting travel time _{t 0.} It measured mounted on the basis of the travel time t _0, measuring the dynamic friction coefficient mu ₁ of the movable table 14 or the load device 15 and the cable 12.

  The installation surface 11 desirably has a dynamic friction force smaller than the dynamic friction force between the cable 12 and the movable table 14 or the load means 15. For the movable table 14 to move, a sufficiently small dynamic friction force between the movable surface 14 and the installation surface 11 may be used, and the movable table 14 may be realized by mounting a wheel having a small dynamic friction force with the shaft. For example, the dynamic frictional force between the installation surface 11 and the movable table 14 is preferably one tenth or less of the dynamic frictional force between the cable 12 and the load means 15. The linear object fixing means 13 fixes the cable 12 so as not to move even when the movable base 14 is pulled. The linear object fixing means 13 only needs to be fixed to the installation surface 11.

  Although the weight 16 is used as the traction means, any means may be used as long as the movable base 14 is kept parallel to the cable 12 and the traction is stopped after the predetermined distance H is pulled with a constant force. For example, it may be provided with a stopper that pulls the distance H by a spring having a length sufficiently longer than the distance H and stops the spring contraction after the distance H is pulled. The movable table 14 may be pulled by a distance H with a motor, and after towing the distance H, the motor may be stopped.

可動台１４についての運動方程式は次式が得られる。

In FIG. 2, the speed of the movable base 14 when the weight 16 falls by the fall distance H is calculated. First, consider weight 16 exercise. Mass W of the weight 16, the gravitational acceleration g, mass _{m 0} of the movable base 14, mass _{m 1} of the load means 15, ₁ dynamic friction coefficient between the movable base 14 or load device 15 and the cable 12 mu, the acceleration Assuming that a is the equation of motion for the weight 16, the following equation is obtained.

The following equation is obtained as an equation of motion for the movable table 14.

これを書き直すと、次式が得られる。

From Equations 1 and 2, the acceleration a is obtained by the following equation.

Rewriting this gives the following equation:

数５より、

となる。落下距離Ｈを落下したとき、重り１６の速度Ｖ_０は、次式となる。

When the fall distance of the weight is H, the time t ₀ required to drop the fall distance H is obtained by the following equation.

From Equation 5,

It becomes. When the drop distance H is dropped, the speed V _{0 of the} weight 16 is as follows.

In this embodiment, as shown in FIG. 2, the weight W of the weight 16, the mass of the movable base 14 is m ₀ , the mass of the load means 15 is m ₁ , the drop distance H is known in advance, and the mounting guide 14a and the load guide 15a And the holding movement time t ₀ , which is the movement time from when the movable base 14 starts to be moved by a predetermined distance while the cable 12a is being clamped, that is, after the weight 16 starts to fall, The mounting movement time t ₀ until the distance H is dropped is measured, and the dynamic friction coefficient μ ₁ is calculated.

数８より、次式が得られる。

From Equations 4 and 5, the dynamic friction coefficient μ ₁ can be calculated as follows.

From Equation 8, the following equation is obtained.

As can be seen from equation 9, the mass W of the weight 16, the mass m ₀ of the movable table _14, from the mass m _1, see fall distance H in advance weight 16 of the load means 15 starts falling, dropping a drop distance H If the mounting movement time t ₀ until it can be measured, the dynamic friction coefficient μ ₁ can be calculated.

A specific example is shown. The weight W of the weight 16 is 0.3 kg, the mass m ₀ of the movable table 14 is 0.2 kg, the mass m ₁ of the load means 15 is 0.1 kg, and the fall distance H is 0.1 m. When the mounting movement time to until the measurement is 0.2259 s, the dynamic friction coefficient μ ₁ = 0.300 is obtained from Equation 9.

Further, the speed V ₀ of the weight 16 at this time is obtained by changing the ratio of the fall distance H or the weight W of the weight 16 and the mass m ₁ of the load means 15 as shown in Equation 7. be able to. As a specific example, V ₀ = 0.89 m / s is obtained under the same conditions as described above. That is, a dynamic friction coefficient is obtained when the cable is inserted or pulled out at a maximum speed of about 0.89 m / s.

  Does the movement time from the start of the fall of the weight 16 to the fall of the fall distance H start from the start of the fall of the weight 16 and the end of the run until the weight 16 drops the fall distance H? Alternatively, the time from the start of the movable table 14 to the start point and the end point from the movable table 14 moving by the distance H may be measured. The travel time may be measured with a timer. Further, a moving time measuring unit (not shown) for calculating a moving time from when the movable table 14 starts to move until the movable table 14 moves by the distance H may be further provided. For example, it is arranged so that the laser beam is crossed by the movement of the movable table 14, and the movable beam 14 crosses the laser beam arranged slightly ahead of the stop position until it crosses the laser beam arranged at the distance H. You may measure travel time in time. Alternatively, the movement time from the start of the displacement of the reflection time of the ultrasonic pulse to the movable table 14 to the maximum displacement may be measured. Alternatively, the moving time from when the weight 16 is dropped to when the weight 16 drops the drop distance H may be measured. The same applies to the following embodiments.

The dynamic friction coefficient calculation means (not shown) calculates the dynamic friction coefficient μ ₁ from the value input in advance and the measured mounting movement time t _{0 according} to Equation 9.

According to the present embodiment, the dynamic friction coefficient μ ₁ can be calculated from the mounting movement time t ₀ until the weight falls the drop distance H without measuring the dynamic friction force. Further, it is possible to measure the dynamic friction coefficient mu ₁ linear, such as communication cables pulling the actual towing speed or drawing speed or in speed above it.

(Second Embodiment)
The second embodiment of the present invention is a case where dynamic friction between the movable table and the installation surface is taken into consideration. A configuration of a dynamic friction coefficient measuring apparatus according to the second embodiment of the present invention will be described with reference to FIGS. 2 and 3, 11 is an installation surface, 12 is a cable as a linear object, 13 is a linear object fixing means for fixing one end of the cable 12, 14 is a movable base movable on the installation surface 11, and 15 is A load means 16 for loading the cable 12, a weight 16 as a traction means for pulling the movable base 14 by a predetermined distance with a constant traction force in a direction opposite to the linear object fixing means 13, 17 is a height of the weight 16. It is a buffer stand that is received when falling from H.

In the present embodiment, as shown in FIG. 3, a no-load moving time t ₁ that is a moving time from when the movable table 14 starts to be moved by a predetermined distance after the movable table 14 starts to be pulled without the cable 12 being mounted. taking measurement. On the other hand, as shown in FIG. 2, with the cable 12 mounted, a mounting movement time t ₀ that is a movement time from when the movable table 14 starts to be pulled until the movable table 14 moves by a predetermined distance is measured. Based on the measured no-load moving time t ₁ and the measured mounting moving time t ₀ , the dynamic friction coefficient μ ₁ between the movable table 14 or the load means 15 and the cable 12 is measured. The order of measurement of the no-load travel time t _{1 and} the measurement of the mounting travel time t ₀ is not important. When measuring the no-load movement time t ₁ , the movable table 14 may or may not be loaded with the load means 15. In the following, the measurement of the no-load travel time t _1, the movable platform 14 is equipped with a load means 15.

可動台１４についての運動方程式は次式が得られる。

Explaining the measurement of the no-load travel time t _1. In FIG. 3, the speed of the movable table 14 when the weight 16 falls by the fall distance H is calculated. First, consider weight 16 exercise. Mass W of the weight 16, the gravitational acceleration g, mass _{m 0} of the movable base 14, mass _{m 1} of the load means 15, ₂ dynamic friction coefficient between the movable base 14 and the installation surface 11 mu, the acceleration was a When the equation of motion for the weight 16 is obtained:

The following equation is obtained as an equation of motion for the movable table 14.

これを書き直すと、次式が得られる。

From Equations 10 and 11, the acceleration a is obtained by the following equation.

Rewriting this gives the following equation:

数１４より、

となる。落下距離Ｈを落下したとき、重り１６の速度Ｖ_０は、次式となる。

When the fall distance of the weight is H, the time t ₁ required to drop the fall distance H is obtained by the following equation.

From Equation 14,

It becomes. When the drop distance H is dropped, the speed V _{0 of the} weight 16 is as follows.

数１７より、次式が得られる。

From Equations 13 and 14, the dynamic friction coefficient μ ₂ can be calculated as follows.

From Equation 17, the following equation is obtained.

As can be seen from Equation 18, the mass W of the weight 16, the mass m ₀ of the movable table _14, from the mass m _1, see fall distance H in advance weight 16 of the load means 15 starts falling, dropping a drop distance H If the no-load movement time t ₁ until the measurement can be measured, the dynamic friction coefficient μ ₂ can be calculated.

A specific example is shown. The weight W of the weight 16 is 0.3 kg, the mass m ₀ of the movable base 14 is 0.2 kg, the mass m ₁ of the load means 15 is 0.1 kg, the drop distance H is 0.1 m, and the cable 12 is not mounted. When the no-load movement time t ₁ until the weight 16 falls by the fall distance H is 0.207 s, the dynamic friction coefficient μ ₂ = 0.048 is obtained from Equation 18.

可動台１４についての運動方程式は次式が得られる。

The measurement of on-board travel time will be described. In FIG. 2, the speed of the movable base 14 when the weight 16 falls by the fall distance H is calculated. First, consider weight 16 exercise. The mass of the weight 16 is W, the acceleration of gravity is g, the mass of the movable table 14 is m ₀ , the mass of the load means 15 is m ₁ , the coefficient of dynamic friction between the movable table 14 or the load means 15 and the cable 12 is μ ₁ , and the movable table. Assuming that the dynamic friction coefficient between 14 and the installation surface 11 is μ ₂ and the acceleration is a, the equation of motion for the weight 16 is obtained as follows.

The following equation is obtained as an equation of motion for the movable table 14.

これを書き直すと、次式が得られる。

From Equations 19 and 20, the acceleration a is obtained by the following equation.

Rewriting this gives the following equation:

数２３より、

となる。落下距離Ｈを落下したとき、重り１６の速度Ｖ_０は、次式となる。

When the fall distance of the weight is H, the time t ₀ required to drop the fall distance H is obtained by the following equation.

From Equation 23,

It becomes. When the drop distance H is dropped, the speed V _{0 of the} weight 16 is as follows.

数２６より、次式が得られる。

数２７から分かるように、重り１６の質量Ｗ、可動台１４の質量ｍ_０、荷重手段１５の質量ｍ_１、落下距離Ｈ、可動台１４と設置面１１との動摩擦係数μ_２が予め分かり重り１６が落下を開始してから、落下距離Ｈを落下するまでの搭載移動時間ｔ_０を測定できれば、動摩擦係数μ_１を算出することができる。 From Equations 22 and 23, the dynamic friction coefficient μ ₁ can be calculated as follows.

From Equation 26, the following equation is obtained.

Number 27 As can be seen from the mass W of the weight 16, the mass _{m 0} of the movable base 14, the mass _{m 1} of the load means 15, fall distance H, the dynamic friction coefficient mu ₂ in advance to understand the weight of the movable base 14 and the installation surface 11 The dynamic friction coefficient μ ₁ can be calculated if the mounting movement time t ₀ from when the 16 starts to fall until the drop distance H is dropped can be measured.

数２８から分かるように、重り１６の質量Ｗ、可動台１４の質量ｍ_０、荷重手段１５の質量ｍ_１、落下距離Ｈが予め分かり重り１６が落下を開始してから、落下距離Ｈを落下するまでの無負荷移動時間ｔ_１、搭載移動時間ｔ_０を測定できれば、動摩擦係数μ_１を算出することができる。 From Equation 27, the following equation can be calculated.

As can be seen from Equation 28, the mass W of the weight 16, the mass m ₀ of the movable table _14, from the mass m _1, see fall distance H in advance weight 16 of the load means 15 starts falling, dropping a drop distance H If the no-load movement time t ₁ and the mounting movement time t ₀ can be measured, the dynamic friction coefficient μ ₁ can be calculated.

A specific example is shown. Weight of weight 16 = 0.3 kg, mass m ₀ of movable base 14 = 0.2 kg, mass of load means 15 m ₁ = 0.1 kg, drop distance H = 0.1 m, dynamic friction coefficient μ ₂ = 0.048 When the mounting movement time to until the drop distance H is dropped is 0.226 s, the dynamic friction coefficient μ ₁ = 0.230 is obtained from Equation 27.

Further, to understand the mass of the weight 16 W = 0.3 kg, the mass _m 0 = 0.2 kg of the movable table 14, the mass _m 1 = 0.1 kg of load means 15, fall distance H = 0.1 m in advance, falling distance H When the no-load movement time t ₁ and the mounting movement time to are measured until they fall 0.2669 s and 0.2259 s, respectively, the dynamic friction coefficient μ ₁ = 0.230 is obtained from Equation 28.

Further, the speed V ₀ of the weight 16 at this time is obtained by changing the drop distance H or the ratio of the weight W of the weight 16 and the mass m ₁ of the load means 15 as shown in Equation 25. be able to. As a specific example, V ₀ = 0.89 m / s is obtained under the same conditions as described above. That is, a dynamic friction coefficient is obtained when the cable is inserted or pulled out at a maximum speed of about 0.89 m / s.

The dynamic friction coefficient calculating means (not shown) calculates the dynamic friction coefficient μ ₁ from the value inputted in advance, the measured dynamic friction coefficient μ ₂ and the mounting movement time t ₀ according to the equation (27). Alternatively, the dynamic friction coefficient μ ₁ is calculated from the value input in advance and the measured no-load travel time t ₁ and mounting travel time t _{0 according} to Equation 28.

According to this embodiment, even if there is a dynamic friction force between the movable table and the installation surface, the dynamic friction coefficient μ ₂ and the weight between the movable table and the installation surface fall without measuring the dynamic friction coefficient μ ₁ from the dynamic friction force. mounting time to fall a distance H t _0, or weight can be calculated from the no-load travel time t ₁ and mounted travel time t ₀ until the fall drop distance H. Further, it is possible to measure the dynamic friction coefficient mu ₁ linear, such as communication cables pulling the actual towing speed or drawing speed or in speed above it.

(Third embodiment)
The third embodiment of the present invention is a case where dynamic friction between the movable table and the installation surface is taken into consideration. The configuration of a dynamic friction coefficient measuring apparatus according to the third embodiment of the present invention will be described with reference to FIG. In FIG. 4, 11 is an installation surface, 12 is a cable as a linear object, 13 is a linear object fixing means for fixing one end of the cable 12, 14 is a movable base movable on the installation surface 11, and 15 is a cable 12 A load means 16 for loading the cable 12 is a weight as a traction means for pulling the movable base 14 by a predetermined distance with a constant traction force in a direction opposite to the linear object fixing means 13, and 17 is a weight 16 from the height H. It is a buffer stand that receives when it falls.

In the present embodiment, as shown in FIG. 4, a no-load stop distance that is a stop distance until the movable base 14 stops by pulling the movable base 14 without mounting the cable 12 is measured. The dynamic friction coefficient μ ₂ between the movable table 14 and the installation surface 11 is calculated from the no-load stop distance. This embodiment is different from the second embodiment in the calculation of the dynamic friction coefficient μ ₂ . Here, describing calculation of the dynamic friction coefficient mu _2. The order of the measurement of the no-load stop distance and the measurement of the mounting travel time is not limited. When measuring the unloaded stopping distance x _t, the movable platform 14 may be equipped with a load means 15, it may not be mounted. In the following, the measurement of the no-load stopping distance x _t, movable base 14 is mounted with the load means 15.

可動台１４についての運動方程式は次式が得られる。

The measurement of the no-load stop distance will be described. In FIG. 4, the speed of the movable table 14 when the weight 16 falls by the fall distance H is calculated. First, consider weight 16 exercise. Mass W of the weight 16, the gravitational acceleration g, mass _{m 0} of the movable base 14, mass _{m 1} of the load means 15, ₂ dynamic friction coefficient between the movable base 14 and the installation surface 11 mu, the acceleration was a When the equation of motion for the weight 16 is obtained:

The following equation is obtained as an equation of motion for the movable table 14.

これを書き直すと、次式が得られる。

From equations 29 and 30, the acceleration a is obtained by the following equation.

Rewriting this gives the following equation:

数３３より、

となる。落下距離Ｈを落下したとき、重り１６の速度Ｖ_０は、次式となる。

When the fall distance of the weight is H, the time t ₀ required to drop the fall distance H is obtained by the following equation.

From Equation 33

It becomes. When the drop distance H is dropped, the speed V _{0 of the} weight 16 is as follows.

Next, consider the movement of the movable table 14 on which the load means 15 is placed. The movable table 14 that has reached the speed V _{0 due} to the fall of the weight 16 is then decelerated by the dynamic frictional force between the movable table 14 and the installation surface 11 and stops. It is assumed that t = 0 when the weight 16 is dropped by the drop distance H, and x = 0 is the position of the movable base 14. Since it is a dynamic frictional force between the movable table 14 and the installation surface 11, the following equation is obtained as an equation of motion for the movable table 14 where acceleration is α.

The acceleration α at this time is given by the following equation.

重り１６が落下距離Ｈを落下してからの時間ｔでの停止位置ｘ（ｔ）は、次式となる。

The speed v (t) at time t after the weight 16 falls the fall distance H is expressed by the following equation.

The stop position x (t) at time t after the weight 16 falls the fall distance H is expressed by the following equation.

となる。 Here, the stop time t _t until the movable base 14 stops due to the dynamic frictional force of the installation surface 11 is obtained by setting v (t) = 0 in Equation 38. That is,

It becomes.

数４０を代入する。

数３５を代入する。

が得られる。 From Equation 40, the no-load stop distance x _t at the time t _t after the weight 16 falls the drop distance H is _expressed by the following equation.

The number 40 is substituted.

Expression 35 is substituted.

Is obtained.

From Equation 43, the dynamic friction coefficient μ ₂ can be calculated as follows.

As can be seen from the number 44, the mass W of the weight 16, the mass _{m 0} of the movable base 14, the mass _{m 1} of the load means 15, see fall distance H in advance, the movable platform 14 from the weight 16 may fall a drop distance H There can if measuring the unloaded stop distance x _t to stop, to calculate the dynamic friction coefficient mu _2.

A specific example is shown. The weight W of the weight 16 is 0.3 kg, the mass m ₀ of the movable base 14 is 0.2 kg, the mass m ₁ of the load means 15 is 0.1 kg, the drop distance H is 0.1 m, and the cable 12 is not mounted. when the movable base 14 from dropping weight 16 only falling distance H was 1.0m as measured no-load stopping distance _{x t} until the stop, from the number 44, the dynamic friction coefficient _mu 2 = 0.048 can get.

The dynamic friction coefficient calculating means (not shown) calculates the dynamic friction coefficient μ ₁ from the value inputted in advance, the measured dynamic friction coefficient μ ₂ and the mounting movement time t ₀ according to the equation (27).

According to this embodiment, even if there is a dynamic friction force between the movable table and the installation surface, the dynamic friction coefficient μ ₂ and the weight between the movable table and the installation surface fall without measuring the dynamic friction coefficient μ ₁ from the dynamic friction force. It can be calculated from the mounting movement time t ₀ until the distance H falls. Further, it is possible to measure the dynamic friction coefficient mu ₁ linear, such as communication cables pulling the actual towing speed or drawing speed or in speed above it.

(Fourth embodiment)
The fourth embodiment of the present invention is a case where dynamic friction between the movable table and the installation surface is taken into consideration. The configuration of a dynamic friction coefficient measuring apparatus according to the fourth embodiment of the present invention will be described with reference to FIG. In FIG. 5, 11 is an installation surface, 12 is a cable as a linear object, 13 is a linear object fixing means for fixing one end of the cable 12, 14 is a movable base movable on the installation surface 11, and 15 is a cable 12 A load means 16 for loading the cable 12 is a weight as a traction means for pulling the movable base 14 by a predetermined distance with a constant traction force in a direction opposite to the linear object fixing means 13, and 17 is a weight 16 from the height H. It is a buffer stand that receives when it falls.

In the present embodiment, as shown in FIG. 5, the no-load stop time, which is a stop time until the movable base 14 stops by pulling the movable base 14 without mounting the cable 12, is measured. The dynamic friction coefficient μ ₂ between the movable table 14 and the installation surface 11 is calculated from the no-load stop time. This embodiment is different from the second embodiment in the calculation of the dynamic friction coefficient μ ₂ . Here, describing calculation of the dynamic friction coefficient mu _2. The order of the measurement of the no-load stop time and the measurement of the mounting movement time is not limited. When measuring the no-load stop time t _t , the movable table 14 may or may not be loaded with the load means 15. Hereinafter, in the measurement of the no-load stop time t _t , the movable table 14 is loaded with the load means 15.

可動台１４についての運動方程式は次式が得られる。

The measurement of the no-load stop time will be described. In FIG. 5, the speed of the movable base 14 when the weight 16 falls by the fall distance H is calculated. First, consider weight 16 exercise. Mass W of the weight 16, the gravitational acceleration g, mass _{m 0} of the movable base 14, mass _{m 1} of the load means 15, ₂ dynamic friction coefficient between the movable base 14 and the installation surface 11 mu, the acceleration was a When the equation of motion for the weight 16 is obtained:

The following equation is obtained as an equation of motion for the movable table 14.

これを書き直すと、次式が得られる。

From equations 45 and 46, acceleration a is obtained by the following equation.

Rewriting this gives the following equation:

数４９より、

となる。落下距離Ｈを落下したとき、重り１６の速度Ｖ_０は、次式となる。

When the fall distance of the weight is H, the time t ₀ required to drop the fall distance H is obtained by the following equation.

From Equation 49

It becomes. When the drop distance H is dropped, the speed V _{0 of the} weight 16 is as follows.

Next, consider the movement of the movable table 14 on which the load means 15 is placed. The movable table 14 that has reached the speed V _{0 due} to the fall of the weight 16 is then decelerated by the dynamic frictional force between the movable table 14 and the installation surface 11 and stops. It is assumed that t = 0 when the weight 16 is dropped by the drop distance H, and x = 0 is the position of the movable base 14. Since it is a dynamic frictional force between the movable table 14 and the installation surface 11, the following equation is obtained as an equation of motion for the movable table 14 where acceleration is α.

The acceleration α at this time is given by the following equation.

The speed v (t) at time t after the weight 16 falls the fall distance H is expressed by the following equation.

となる。数５５、数５１から

Here, a no-load stop time t _t that is a stop time until the movable base 14 stops due to the dynamic frictional force of the installation surface 11 is obtained by setting v (t) = 0 in Formula 54. That is,

It becomes. From Formula 55 and Formula 51

As can be seen from the number 56, the mass W of the weight 16, the mass _{m 0} of the movable base 14, the mass _{m 1} of the load means 15, fall distance H is know in advance, the movable platform 14 from the weight 16 may fall a drop distance H If the no-load stop time t _t until the motor stops can be measured, the dynamic friction coefficient μ ₂ can be calculated.

A specific example is shown. The weight W of the weight 16 is 0.3 kg, the mass m ₀ of the movable base 14 is 0.2 kg, the mass m ₁ of the load means 15 is 0.1 kg, the drop distance H is 0.1 m, and the cable 12 is not mounted. When the no-load stop distance time t _t from when the weight 16 is dropped by the drop distance H to when the movable table 14 is stopped is 2.05 s, the dynamic friction coefficient μ ₂ = 0.048 is obtained from Equation 56. Is obtained.

The dynamic friction coefficient calculating means (not shown) calculates the dynamic friction coefficient μ ₁ from the value inputted in advance, the measured dynamic friction coefficient μ ₂ and the mounting movement time t ₀ according to the equation (27).

According to this embodiment, even if there is a dynamic friction force between the movable table and the installation surface, the dynamic friction coefficient μ ₂ and the weight between the movable table and the installation surface fall without measuring the dynamic friction coefficient μ ₁ from the dynamic friction force. It can be calculated from the mounting movement time t ₀ until the distance H falls. Further, it is possible to measure the dynamic friction coefficient mu ₁ linear, such as communication cables pulling the actual towing speed or drawing speed or in speed above it.

  The dynamic friction coefficient measuring apparatus and the dynamic friction coefficient measuring method of the present invention can be applied to the measurement of the dynamic friction coefficient of a linear object such as a cable.

11: Installation surface 12: Cable as a linear object 13: Linear object fixing means 14: Movable base 14a: Mounting guide 15: Load means 15a: Load guide 16: Weight as a traction means 17: Buffer base 19: Load means Fixed guide

Claims (15)

A dynamic friction coefficient measuring device for measuring a dynamic friction coefficient of a linear object,
A linear object fixing means for fixing one end of the linear object;
A movable base having a mounting guide for mounting the linear object, and movable on the installation surface;
A load guide that contacts the linear object facing the mounting guide of the movable table, and a load unit that loads the linear object via the load guide;
Traction means for towing the movable table by a predetermined distance with a constant traction force in a direction opposite to the linear object fixing means;
A moving time measuring means for measuring a moving time from the start of pulling the movable table until the movable table moves by the predetermined distance, and
The dynamic friction coefficient measuring device according to claim 1, wherein contact surfaces of the mounting guide and the load guide with the linear object are flat.   This is the movement time from when the movable base starts to move by the predetermined distance after starting to pull the movable base while holding the linear object between the mounting guide and the load guide measured by the moving time measuring means. The dynamic friction coefficient measuring device according to claim 1, further comprising dynamic friction coefficient calculation means for calculating a dynamic friction coefficient of the linear object from a mounting movement time.   The mounting movement time and the linear object, which are the movement time until the movable table is moved by the predetermined distance while holding the linear object between the mounting guide and the load guide measured by the moving time measuring means. The dynamic friction coefficient measuring device according to claim 1, further comprising dynamic friction coefficient calculating means for calculating a dynamic friction coefficient of the linear object from a dynamic friction coefficient between the movable table and the installation surface when the vehicle is not mounted.   The movable base and the installation from the no-load movement time, which is the movement time from when the dynamic friction coefficient calculating means starts to pull the movable base without mounting the linear object until the movable base moves by a predetermined distance The dynamic friction coefficient measuring apparatus according to claim 3, wherein a dynamic friction coefficient with a surface is calculated.   The movable friction coefficient calculating means is configured to install the movable base and the installation from a no-load stop distance that is a stop distance from when the movable base is stopped by pulling the movable base by a predetermined distance without mounting the linear object. The dynamic friction coefficient measuring apparatus according to claim 3, wherein a dynamic friction coefficient with a surface is calculated.   The dynamic friction coefficient calculating means is configured to install the movable base and the installation from a no-load stop time which is a stop time until the movable base stops after the movable base is pulled by a predetermined distance without mounting the linear object. The dynamic friction coefficient measuring apparatus according to claim 3, wherein a dynamic friction coefficient with a surface is calculated.   The dynamic friction coefficient measuring device according to any one of claims 1 to 6, wherein the pulling means has a weight that pulls the movable table and drops from the same height as the predetermined distance.   The dynamic friction coefficient according to any one of claims 1 to 7, wherein a material of a contact surface of the mounting guide and the load guide with the linear object is the same as a material of a surface of the linear object. measuring device. A dynamic friction coefficient measuring method for measuring a dynamic friction coefficient of a linear object,
Fix one end of the wire,
The linear object is mounted, a mounting guide having a flat shape of a contact surface with the linear object, a movable base movable on the installation surface, and the line facing the mounting guide of the movable base A load guide that accommodates a linear object and has a load guide with a flat shape of a contact surface with the linear object, and a load unit that loads the linear object with the load guide, while holding the linear object Tow the movable table by a predetermined distance with a constant traction force in the direction of the other end of the linear object,
The dynamic friction coefficient of the linear object is measured by measuring a mounting movement time which is a movement time from when the movable base starts to be pulled until the movable base moves by the predetermined distance. Coefficient measurement method.   The dynamic friction coefficient according to claim 9, wherein the dynamic friction coefficient of the linear object is calculated from the mounting movement time and the dynamic friction coefficient between the movable table and the installation surface when the linear object is not mounted. Measuring method.   When the linear object is not mounted, the coefficient of dynamic friction between the movable table and the installation surface pulls the movable table by a predetermined distance with a constant traction force without mounting the linear object, and pulls the movable table. The dynamic friction coefficient measuring method according to claim 10, wherein the dynamic friction coefficient measuring method is calculated by measuring a no-load moving time which is a moving time until the movable platform moves by the predetermined distance after starting to move.   The coefficient of dynamic friction between the movable base and the installation surface when the linear object is not mounted is the time from when the movable base is pulled by a predetermined distance without mounting the linear object until the movable base stops. The dynamic friction coefficient measuring method according to claim 10, wherein the calculation is performed by measuring a no-load stop distance that is a stop distance.   The coefficient of dynamic friction between the movable base and the installation surface when the linear object is not mounted is the time from when the movable base is pulled by a predetermined distance without mounting the linear object until the movable base stops. The dynamic friction coefficient measurement method according to claim 10, wherein the calculation is performed by measuring a no-load stop time that is a stop time.   14. The movable table is pulled by a predetermined distance with a constant traction force by dropping a weight for pulling the movable table from the same height as the predetermined distance. The dynamic friction coefficient measuring method as described.   The dynamic friction coefficient according to any one of claims 9 to 14, wherein a material of a contact surface of the mounting guide and the load guide with the linear object is the same as a material of the surface of the linear object. Measuring method.

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