JP3336902B2 - Viscoelasticity measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a viscoelasticity measuring device for measuring the viscoelasticity of an object to be measured from the motion characteristics of a pendulum that freely vibrates in contact with the object.

[0002]

2. Description of the Related Art In many cases, coatings, adhesives, thermoplastic or thermosetting polymer structural materials, etc. are applied to various mating materials to form films. A viscoelasticity measuring device using a rigid pendulum is conventionally known as a device for measuring viscoelasticity in such film formation. As such a viscoelasticity measuring device and a rigid pendulum for viscoelasticity measurement, for example, FIGS.
(See Japanese Utility Model Laid-Open No. 5-40869).

As shown in FIG. 4, the viscoelasticity measuring device 8 comprises a rigid pendulum 9 for measuring viscoelasticity, a driving device 81 for exciting the rigid pendulum 9 for measuring viscoelasticity, and a vibration of the rigid pendulum 9 for measuring. It has a displacement meter 83 for measuring displacement, an output device 86 for recording the vibration displacement of the rigid pendulum 9 for measurement, and a control unit 80. In the figure, reference numeral 82 denotes an electromagnet that is excited by the driving device 81, and reference numeral 84 denotes a displacement sensor that detects the displacement of the pendulum 9.

A rigid pendulum 9 for measuring viscoelasticity (hereinafter also simply referred to as a rigid pendulum) 9 has an edge portion 91 as shown in FIG.
And a frame portion 93 and a rod-shaped mass member 9 vertically provided below the frame portion 93.
4 As shown in FIG. 6, the edge portion 91 has a tip portion 910 that comes into contact with the viscoelastic film 70 that is the object to be measured.
Oscillate (single vibration) with 10 as a fulcrum. The mass member 94 is a part for securing an inertia moment in the vibration of the edge part 91. The mass member 94 has a vibrating piece 95 near its lower end and a displacement piece 96 near its center.

FIG. 6 shows the measurement of viscoelasticity.
As shown in the figure, first, the tip 910 of the edge 91 is brought into contact with the film formation 70. Then, as shown in FIG. 4, the vibration piece 95 of the mass member 94 is connected to the control unit 80, the driving device 81,
At first, the electromagnet 82 sucks rightward by electromagnetic force, then stops the suction and vibrates freely. Thus, the rigid pendulum 9 is in contact with the film 70 to be measured,
The pendulum oscillates in the left-right direction in FIG. 5B with the tip 910 of the edge as a fulcrum.

Therefore, this vibration is measured by a displacement sensor 84 arranged near the displacement piece 96 as shown in FIG. Then, the input signal of the displacement sensor 84 is
3, via the control unit 80, is output to the output device 86 as displacement data. At this time, when the film 70 has a high viscoelasticity, the vibration decay is fast, and when the film 70 has a low viscoelasticity, the vibration decay is slow. By measuring this, the viscoelasticity of the film can be measured.

That is, the vibration of the rigid pendulum is a damped vibration obtained by combining the original simple vibration of the pendulum and the viscoelasticity of the object to be measured. Therefore, by measuring the amplitude damping rate and the vibration period in the displacement damping characteristic, The viscoelasticity of the measured object can be analyzed by calculation. Note that in FIG.
Denotes a base on which a film is formed, and 73 denotes a support thereof.

The input to the electromagnet 82 and the displacement of the rigid pendulum 9 will be described more specifically. First, as shown in FIG. 7A, the electromagnet 82 is excited for a predetermined period T, and the vibrating piece 95 is moved. It is attracted to the electromagnet 82 and the rigid pendulum 9 is displaced to the maximum as shown in FIG. Thereafter, the excitation of the electromagnet 82 is released, and the rigid pendulum 9 is freely vibrated. As a result, the rigid pendulum 9 oscillates under the influence of the viscoelasticity of the film 70 (curve 85). Then, the characteristics of the damped vibration are analyzed to determine the viscoelasticity of the film 70.

[0009]

However, the above-mentioned conventional viscoelasticity measuring apparatus has the following problems. that is,
When the vibrating piece 95 is first attracted to the electromagnet 82, creep deformation occurs in the object to be measured. As a result, the damping vibration curve 85 of the rigid pendulum 9 shown in FIG. 7 is deformed, making analysis difficult and causing errors. Is to make.

That is, as shown in FIG. 8, a damping vibration curve 85 of the rigid pendulum 9 is represented by a monotonous damping curve 852 (FIG. 8B) due to the restoration of the creep deformation of the film 70 and the rigid pendulum 9. A damped vibration curve 851 caused by free vibration is superimposed. And the above creep occurs
When the rigid pendulum 9 is stopped by being attracted to the electromagnet 82, it occurs only in a certain range of viscoelasticity. here,
Since the object to be analyzed for the viscoelasticity is the damped vibration curve 851 composed of the damping rate of the amplitude and the vibration period as described above, the monotonous damping curve 852 caused by the creep deformation is a factor of the measurement error of the viscoelasticity. Become.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and it is an object of the present invention to eliminate the influence of creep of an object to be measured and to measure a viscoelastic value with high accuracy irrespective of the magnitude of viscoelasticity. It is an object of the present invention to provide a viscoelasticity measuring device that can perform the above.

[0012]

The present invention relates to a viscoelasticity measuring apparatus for measuring the viscoelasticity of an object to be measured from the motion characteristics of a pendulum that freely vibrates in contact with the object to be measured. A sample table to be mounted, a pendulum that freely vibrates left and right around a rotation fulcrum that presses the mounting surface of the object to be measured, vibration means for driving the pendulum, and measurement means for measuring displacement of the pendulum Wherein the vibrating means vibrates by applying a driving force having a period corresponding to the free vibration period of the pendulum.

In the present invention, it should be particularly noted that
The vibrating means vibrates by applying a driving force having a period corresponding to the free vibration period of the pendulum. That is, the pendulum is excited according to its own free vibration cycle (excitation period), and thereafter, the driving by the vibration means is stopped and the pendulum shifts to damped free vibration (measurement period). As a result, the vibration period of the displacement between the excitation period and the measurement period coincides with each other, and a period during which the motion stops causing a creep deformation of the measured object (curve 850 in FIG. 7B) does not occur. .

Therefore, the monotonous damping curve 852 deviated to one side due to the creep as shown in FIG. 8 is not included in the vibration curve of the displacement, and the vibration curve of the displacement at the time of the measurement has the attenuation of the amplitude and the free vibration. A desired damped vibration curve consisting of vibration is obtained. As described above, according to the present invention, it is possible to provide a viscoelastic device capable of eliminating the influence of creep of an object to be measured and measuring a viscoelastic value with high accuracy regardless of the magnitude of viscoelasticity. it can.

The vibrating means includes, for example, an electromagnet and a variable voltage variable frequency power supply (VVV
F) and a magnetic body disposed on the pendulum facing the electromagnet.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION

1. Embodiment Example As shown in FIG. 1, the present embodiment is a viscoelasticity measuring apparatus 1 for measuring the viscoelasticity of an object to be measured from the motion characteristics of a pendulum 10 that freely vibrates in contact with the object to be measured. The viscoelasticity measuring device 1
A sample table 21 on which an object to be measured is mounted on a surface, a pendulum 10 which freely vibrates to the left and right around a rotation fulcrum 12 which presses the mounting surface 211 of the object to be measured, and a vibrator which drives the pendulum 10 It has means 30 and measuring means (displacement sensor 35, displacement meter 36) for measuring the displacement of the pendulum 10. In the figure, reference numeral 51 denotes a base installed on the floor.

Then, as shown by the curve 61 in FIG.
Vibration is given by applying a driving force having a cycle corresponding to the free vibration cycle of Further, as shown in FIG. 1, the vibration means 30 includes an electromagnet 31, a variable voltage variable frequency power supply 32 for driving the electromagnet 31, and a magnetic body 33 disposed on the pendulum 10 so as to face the electromagnet 31. . The power supply 32 is connected to the control device 4.
Controlled by 0. Then, from the data measured by the displacement meter 36, the control device 40 calculates the amplitude attenuation rate and the vibration period in the displacement attenuation characteristics, and analyzes the viscoelasticity of the measured object.

The following is a supplementary explanation for each. As shown in FIG. 3, the pendulum 10 includes a frame 13 installed on a sample table 21 and a rod-shaped mass member 14 extending therebelow.
And the edge portion 11 which forms the upper side of the frame portion 13. The edge portion 11 is provided on the horizontal mounting surface 211 of the sample stage 21.
The tip part (rotation fulcrum 1) that comes into contact with the DUT placed on
2), and the pendulum 10 swings (single oscillation) about the rotation fulcrum 12. Further, the mass member 14 is a member for securing a moment of inertia of the vibration of the pendulum 10 to a certain level or more. The mass member 14 has a vibrating piece 33 near its lower end and a displacement piece 34 near its center.

FIG. 6 shows the measurement of viscoelasticity.
As shown in (1), the tip of the edge portion 11 is first brought into contact with the object to be measured on the mounting surface 211. And pendulum 10
The free vibration period of the is measured. The free vibration period of the pendulum 10 changes as the viscoelasticity of the object to be measured changes during the measurement, and is not always constant. It is necessary to measure the oscillation period.

In order to measure the free vibration period of the pendulum 10, when the pendulum is vibrating, the above-described vibration measurement function inherent in the present apparatus is used. If the amplitude is smaller than the above-mentioned vibration measurement function can be used even when the pendulum 10 is stationary or vibrates, the electromagnet 31 is excited only once over a period shorter than the lower limit of the measurable vibration period. By doing so, a vibration state in which the vibration measurement function can be used can be obtained.

Then, as shown by a curve 61 in FIG. 2 (a), the electromagnet 31 is first excited for a certain period of time T with a period that matches the free vibration period of the pendulum 10. as a result,
As shown by a curve 621 in FIG.
The vibration of the above-mentioned vibration period is excited in the left-right direction of (b). Then, after the fixed period T, the excitation is stopped, and the pendulum 10 is opened to freely vibrate. This allows pendulum 1
Reference numeral 0 denotes a pendulum vibration in the left-right direction in FIG. 3B with the rotation fulcrum 12 at the tip of the edge portion 11 as a fulcrum while in contact with the object to be measured.

Then, this vibration is measured by a displacement sensor 35 arranged near the displacement piece 34. The input signal of the displacement sensor 35 is transmitted from the displacement meter 36 to the control device 40.
Is input as displacement data. And the control device 40
Analyzes the characteristics of the damped vibration of the pendulum 10 and calculates the viscoelasticity of the measured object.

As described above, the pendulum 10 is excited according to its own free vibration cycle (= excitation period), and thereafter, the driving by the vibration means 30 is stopped to shift to damped free vibration (= measurement period). . Therefore, the vibration period of the displacement between the excitation period and the measurement period coincides, and the motion is biased to cause creep deformation of the measured object (for example, the curve 850 in FIG. 7).
Suspension period) does not occur.

Therefore, the monotonous damping curve 852 deviated to one side due to creep as shown in FIG. 8 is not included in the vibration curve of displacement, and as shown by the curve 622 in FIG. The displacement vibration curve is a desired damped vibration curve composed of amplitude damping and free vibration. That is.
According to the present apparatus 1, it is possible to measure the viscoelasticity value with high accuracy irrespective of the magnitude of the viscoelasticity by eliminating the influence of creep of the measured object.

[0025]

As described above, according to the present invention, a viscoelastic device capable of eliminating the influence of creep of a measured object and measuring a viscoelastic value with high accuracy regardless of the magnitude of viscoelasticity. Can be obtained.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of a viscoelasticity measuring device according to an embodiment.

FIG. 2 is a diagram showing an excitation curve (a) of an electromagnet and a displacement curve (b) of a pendulum in the viscoelasticity measuring device of the embodiment.

FIG. 3 is a front view (a) and a side view (b) of a pendulum of the viscoelasticity measuring device of the embodiment.

FIG. 4 is a system configuration diagram of a conventional viscoelasticity measuring device.

FIG. 5 is a front view of a pendulum of a conventional viscoelasticity measuring device (a).
And a side view (b).

FIG. 6 is a partially enlarged view of a mounting portion of the viscoelasticity measuring apparatus of FIG.

FIG. 7 is a diagram showing an excitation curve (a) of an electromagnet and a displacement curve (b) of a pendulum in a conventional viscoelasticity measuring apparatus.

FIG. 8 is an enlarged view (c) of a free vibration portion of the displacement curve in FIG. 7;
And a monotone damping curve (DC component) (b) and a damped vibration component (a) included in the free vibration portion.

[Explanation of symbols]

 1. . . 10. Viscoelasticity measuring device, . . Pendulum, 21. . . Sample stage, 211. . . Mounting surface, 30. . . Vibrating means, 35. . . Displacement sensor, 36. . . Displacement meter,

──────────────────────────────────────────────────続 き Continued on the front page (56) References Japanese Utility Model Hei 5-40869 (JP, U) Seiji Ushini, Prototype of flexural vibration measuring device and measurement of viscoelasticity of coating film, Coloring material, Japan, Japan Coloring Material Association Vol., January 20, 1978. 51, No. 1, pp. 10-17 (58) Field surveyed (Int. Cl. ⁷ , DB name) G01N 11/00-11/16 G01N 19/00 JICST file (JOIS)

Claims (1)

(57) [Claims] 1. A viscoelasticity measuring device for measuring the viscoelasticity of an object to be measured from the motion characteristics of a pendulum that freely vibrates in contact with the object to be measured. A pendulum that freely vibrates to the left and right around a rotation fulcrum that presses the mounting surface of the object to be measured, vibrating means for driving the pendulum, and measuring means for measuring displacement of the pendulum. And a vibrating means for vibrating the vibrating device, wherein the vibrating means vibrates by applying a driving force having a period corresponding to a free vibration period of the pendulum.