JP2022108850A - Testing device - Google Patents

Abstract

To provide a testing device that can detect a testing force with higher accuracy.SOLUTION: A testing device performs a test for detecting the amount of displacement occurring when a testing force is applied to a test piece, and the testing device comprises: an indenter that is provided on a cross head moved by a load mechanism and applies a testing force to one face of the test piece; a load detector that is provided on the cross head to detect the testing force applied to the test piece; a probe that is arranged at a position opposite to the indenter with the test piece therebetween; a displacement detector that detects, from the amount of movement of the probe, the amount of displacement of the test piece occurring when the testing force is applied; and an urging member that connects the probe and the indenter to each other, and urges the probe to be in contact with the indenter with the test piece therebetween.SELECTED DRAWING: Figure 1

Description

The present invention relates to test equipment.

2. Description of the Related Art Conventionally, there is known a material testing apparatus that performs a bending test by applying a test force to a test piece supported by a pair of fulcrums. In such a test device, a load is applied to the test piece by pushing an indenter into the test piece from above. The test force applied to the test piece is detected by a load cell provided on the indenter (see, for example, Patent Document 1).

In addition, such a test apparatus uses a contact-type displacement detector that detects the displacement that occurs in the test piece when the indenter is pushed into the test piece by bringing the tip of the probe into contact with the center of the test piece. What is known is known.
Such a probe sandwiches the test piece and contacts the test piece at a position facing the indenter. Additionally, the probe is supported by a spring member that resiliently biases it toward the specimen.

JP 2012-251901 A

However, in the conventional configuration, the test force applied by the indenter to the test piece compresses the spring member and stores repulsive energy in the spring member. For this reason, as the amount of displacement of the test piece increases, there is a possibility that the error included in the detected value of the load cell increases.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a test apparatus capable of detecting a test force with higher accuracy.

A first aspect of the present invention is a test apparatus that performs a test for detecting the amount of displacement caused by applying a test force to a test piece, wherein a crosshead that is moved by a load mechanism is provided with one surface of the test piece. an indenter that applies a test force to the crosshead; a load detector that is provided on the crosshead and detects the test force applied to the test piece; a probe, a displacement detector that detects the amount of displacement of the test piece caused by applying a test force from the amount of movement of the probe, the probe and the indenter are connected, and the test is performed on the indenter. and an urging member that urges the probe to abut against the strip.

According to the first aspect of the invention, the biasing member supports the probe on the indenter. This suppresses the force that supports the probe from being applied to the load detector.
Therefore, the test force can be detected with higher accuracy.

It is a figure which shows typically the testing apparatus which concerns on this Embodiment. FIG. 4 is a diagram schematically showing the configuration of the inside of a constant temperature bath and the displacement detection unit when starting a test; FIG. 4 is a diagram schematically showing the configuration of a displacement detector;

[1. Configuration of test equipment]
[1-1. Overall configuration of test equipment]
Hereinafter, this embodiment will be described with reference to the drawings.
FIG. 1 is a diagram schematically showing a testing apparatus 1 according to this embodiment. In addition, in FIG. 1, the constant temperature bath 3 is shown with a dashed line for convenience of explanation.
The test apparatus 1 of this embodiment applies a test force F to the test piece TP to perform a bending test for measuring mechanical properties such as bending strength, yield point, and deflection of the sample. The test force F is the pressing force.
The test apparatus 1 includes a test apparatus main body 2 for performing a bending test by applying a test force F to a test piece TP, which is a material to be tested, a thermostat 3, a control of the bending test operation by the test apparatus main body 2, and a thermostat. and a control unit 4 for performing temperature control of 3.

The testing apparatus main body 2 includes a table 26, a pair of screw rods 28, 29 vertically rotatably erected on the table 26, and movable along the screw rods 28, 29. A crosshead 10, a load mechanism 12 that moves the crosshead 10 to apply a load to the test piece TP, and a load cell 14 are provided. The load cell 14 is a sensor that measures a test force F, which is a pressing load applied to the test piece TP, and outputs a test force measurement signal SG1.

The load mechanism 12 includes worm reduction gears 16 and 17 connected to lower ends of the screw heads 28 and 29, servo motors 18 connected to the worm reduction gears 16 and 17, and a rotary encoder 20. The rotary encoder 20 is a sensor that measures the amount of rotation of the servomotor 18 and outputs a rotation measurement signal SG2 having the number of pulses corresponding to the amount of rotation to the control unit 4 .
The load mechanism 12 transmits the rotation of the servomotor 18 to a pair of screw necks 28 and 29 through the worm reduction gears 16 and 17, and the screw necks 28 and 29 rotate synchronously so that the crosshead is rotated. 10 moves up and down along the screw rods 28,29.

The constant temperature bath 3 is a housing whose sides are covered with heat insulating walls. In this embodiment, the constant temperature bath 3 is arranged between the respective screw rods 28 , 29 and between the crosshead 10 and the table 26 . Also, the constant temperature bath 3 is positioned above the table 26 so as to be separated from the upper surface of the table 26 .
The constant temperature bath 3 has a space S inside which the test piece TP is accommodated, and the temperature in the space S can be controlled. Note that the test apparatus 1 is not limited to this, and may be provided with various test chambers such as a constant humidity chamber capable of controlling humidity and a constant temperature and humidity chamber capable of controlling both temperature and humidity. Further, the constant temperature bath 3 may be provided with various temperature testing devices.

A pair of fulcrums 22 are provided on the bottom wall of the constant temperature bath 3 . These fulcrums 22 are formed in a columnar shape extending upward from the bottom wall of the constant temperature bath 3 . A pair of fulcrum 22 is provided along the longitudinal direction of the crosshead 10 so that a mutual distance (distance between fulcrums) can be changed.
The test piece TP is placed on the upper ends of the pair of fulcrums 22 in the space S. That is, the pair of fulcrums 22 support the test piece TP from the bottom surface. The test piece TP supported by the pair of fulcrums 22 is arranged with its longitudinal direction along the longitudinal direction of the crosshead 10 .

Through holes 23 and 24 are provided in both the top wall and the bottom wall of the constant temperature bath 3 . These through holes 23 and 24 are provided at positions facing each other.

As described above, the crosshead 10 is provided with the load cell 14, which is a load detector that detects the test force F applied to the test piece TP, and the indenter 21 that contacts the surface of the test piece TP.
The load cell 14 is formed in a columnar shape having a predetermined length extending downward along the vertical direction from the bottom surface of the crosshead 10 .
In the present embodiment, the load cell 14 is inserted through the through hole 23 and the lower end side is arranged in the space S of the constant temperature bath 3 . Note that the load cell 14 is not limited to this, and the entire load cell 14 may be arranged outside the constant temperature bath 3 .

The indenter 21 is provided at the lower end of the load cell 14 . The indenter 21 is a member whose lower end abuts the upper surface (one surface) of the test piece TP when the bending test is performed. In this embodiment, the indenter 21 abuts on the center of the test piece TP in the longitudinal direction when the bending test is performed. Further, the indenter 21 is inserted through the through hole 23 and at least the lower end thereof is arranged in the space S of the constant temperature bath 3 .
The indenter 21 is provided with a connecting member 25 at a position above the lower end of the indenter 21 . The connecting member 25 is a flat plate member extending along the longitudinal direction of the crosshead 10 .

A support base 27 is provided on the table 26 at a position facing the load cell 14 . A through hole 39 is provided in the upper surface of the support base 27 . Furthermore, a displacement detector 30 is provided on the upper surface of the support base 27 . This displacement detector 30 measures the deflection of the central portion of the test piece TP in a contact manner.

The control unit 4 takes in the test force data from the load cell 14 and the data from the displacement detector 30 and executes data processing. By such processing such as calculation in the control unit 4, the test force F (bending load) on the test piece TP and the deflection of the test piece TP are obtained.

The control unit 4 includes a processor such as a CPU and an MPU, and a computer having a memory device such as a ROM and a RAM.

The control unit 4 is connected to the test apparatus main body 2 and the constant temperature chamber 3 so that signals can be transmitted and received. The signals received from the test apparatus main body 2 include a test force measurement signal SG1 output by the load cell 14, a rotation measurement signal SG2 output by the rotary encoder 20, an elongation measurement signal SG3 output by the displacement sensor 15, and appropriate signals required for control and testing. signal, etc. Signals received from the constant temperature chamber 3 are appropriate signals required for controlling and testing the constant temperature chamber 3 .
The control unit 4 takes in test force data from the load cell 14 and data from the displacement detector 40 and performs data processing.

The control unit 4 accepts user operations such as setting operation of various setting parameters such as test conditions of the bending test, or user operation such as execution instruction operation, and has a function of outputting to the test apparatus main body 2 and the constant temperature chamber 3, and outputting the test force measurement value. Equipped with functions such as data analysis.

[1-2. Configuration of Displacement Detector]
Next, the configuration of the displacement detection section 30 will be described.
FIG. 2 is a diagram schematically showing the configuration of the interior of the constant temperature bath 3 and the displacement detection section 30 when the test is started. In addition, in FIG. 2, the constant temperature bath 3 is shown with a dashed line for convenience of explanation.
As described above, the displacement detection unit 30 is attached to the testing device 1 for bending tests, and measures the deflection of the central portion of the test piece TP in a contact manner. As shown in FIG. 2, the displacement detector 30 includes a probe 32 that is inserted through the through hole 24 and is movable along the axial direction of the load applied by the indenter 21, and a displacement detector 40 that is connected to the probe 32. and The displacement detector 40 is arranged outside the constant temperature bath 3, as shown in FIG.

The probe 32 includes a shaft portion 34 , a tip portion 36 and a connecting member 38 .
The shaft portion 34 is a rod-shaped member extending along the axial direction of the load applied by the indenter 21 . The shaft portion 34 is inserted through the through hole 24 . Also, the lower end of the shaft portion 34 is inserted through the through hole 39 of the support base 27 .
The tip portion 36 is provided at the upper end of the shaft portion 34 . The distal end portion 36 is a columnar member having a diameter greater than that of the shaft portion 34 .
The connecting member 38 is a plate-like member extending along the longitudinal direction of the crosshead 10 like the connecting member 25 . A through hole 39 having a larger diameter than the shaft portion 34 and a smaller diameter than the tip portion 36 is provided in the center of the flat plate portion of the connecting member 38 .
In the probe 32 , the upper end of the shaft portion 34 is inserted through the through hole 39 , and the lower end of the tip portion 36 contacts the flat plate portion of the connecting member 38 .

In the test device 1 of the present embodiment, the connecting member 25 and the connecting member 38 are connected by a plurality of spring members 50 .
These spring members 50 are an example of biasing members, and the spring members 50 are so-called tension springs. Each of these spring members 50 has one end connected to the lower surface of the flat plate portion of the connecting member 25 and the other end connected to the upper surface of the flat plate portion of the connecting member 38 .
In this embodiment, one spring member 50 is provided on each side of the indenter 21 along the longitudinal direction of the crosshead 10 and one on each side of the indenter 21 along the width direction of the crosshead 10 . A total of four are provided.
Thereby, the probe 32 is suspended from the indenter 21 via each spring member 50 . In other words, the probe 32 is supported by the indenter 21 .

Also, as described above, each spring member 50 is a tension spring, so the probe 32 is biased toward the indenter 21 . When the test piece TP is not placed on the fulcrum 22 , the tip of the tip portion 36 of the probe 32 contacts the lower end of the indenter 21 due to the biasing force of these spring members 50 .

Further, when the test piece TP is placed on the fulcrum 22, each spring member 50 is stretched to separate the tip of the tip portion 36 of the probe 32 and the lower end of the indenter 21, so that the tip portion 36 and the indenter 21 are separated from each other. be placed between Thereafter, the probe 32 is pulled up by the urging force of each spring member 50, the lower end of the indenter 21 contacts the upper surface of the test piece TP, and the upper end of the tip portion 36 contacts the lower surface (other surface) of the test piece TP. .
Thereby, the test piece TP is supported by the fulcrum 22 and sandwiched between the indenter 21 and the probe 32 .

[1-2. Configuration of Displacement Detector]
Next, the configuration of the displacement detector 40 will be described.
FIG. 3 is a diagram schematically showing the configuration of the displacement detector 40. As shown in FIG.
As shown in FIG. 3, the displacement detector 40 includes a displacement detector body 42, a spindle 44, and a moving body 47. As shown in FIG.

The displacement detector main body 42 is provided with an insertion hole 46 through which a spindle 44, which is a columnar member having a predetermined length dimension, is inserted. The insertion hole 46 extends along the direction of movement of the shaft portion 34, that is, the axial direction of the load applied by the indenter 21, and the lower end side of the insertion hole 46 is open.

The spindle 44 is inserted through the insertion hole 46 from the lower end side opening of the insertion hole 46 . The spindle 44 is vertically movable along the insertion hole 46 .
The displacement detector body 42 has a linear scale. The displacement detector main body 42 detects the amount of movement of the spindle 44 moving inside the insertion hole 46 with this linear scale.
The displacement detector body 42 outputs the detected movement amount to the control unit 4 as data.
As the displacement detection means for the spindle 44 provided in the displacement detector main body 42, for example, another system such as a differential transformer system may be adopted.
The displacement detector main body 42 is supported by the support base 27, for example.

A lower end of the spindle 44 is supported by a moving body 47 .
The moving body 47 is provided integrally with the shaft portion 34 and moves together with the shaft portion 34 .
The spindle 44 is supported by this moving body 47 from its lower end.

[2. action]
Next, the operation of this embodiment will be described.
When starting a test using the test apparatus 1 , the test piece is supported by the TP fulcrum 22 and sandwiched between the indenter 21 and the probe 32 .
In this state, zero point adjustment is performed on the load cell 14 and the displacement detector main body 42 .
Thereafter, by lowering the crosshead 10, a test force F (bending load) is applied to the test piece TP. In this case, the test force F acting on the test strip TP is detected by the load cell 14 and input to the control unit 4 .

When the crosshead 10 is lowered, the test piece TP bends, and the probe 32 descends along the axial direction of the load applied by the indenter 21 while maintaining a distance from the lower end of the indenter 21 .
As described above, the probe 32 is supported by the indenter 21 by being hung from the indenter 21 , so that the force for supporting the probe 32 is suppressed from being applied to the load cell 14 . Therefore, the test apparatus 1 can detect the test force F acting on the test piece TP with higher accuracy.

When the probe 32 descends, the moving body 47 descends together with the probe 32 concerned. That is, the moving body 47 supporting the spindle 44 descends, and the spindle 44 moves vertically downward together with the moving body.
The displacement detector body 42 detects the amount of movement of the spindle 44, and the detected amount of movement is detected as deflection of the test piece TP. The displacement detector body 42 outputs the detected deflection to the control unit 4 as data.

In this way, the spindle 44 is supported by the moving body 47, and is configured to move vertically downward together with the moving body 47 moved by the bending of the test piece TP. This suppresses the force that supports the spindle 44 from being applied to the displacement detector main body 42 . Therefore, the test apparatus 1 can detect the deflection of the test piece TP with higher accuracy.

As described above, the displacement detector 40 is arranged outside the constant temperature bath 3 . As a result, the displacement detector 40 is not affected by the temperature control of the constant temperature bath 3, and a decrease in accuracy due to temperature drift or the like is suppressed. Therefore, the displacement detector 40 can be used in the test apparatus 1 without improving heat resistance, for example.

Further, since the displacement detector 40 is arranged outside the thermostatic chamber 3 , a predetermined distance is provided between the displacement detector 40 and the test piece TP arranged inside the thermostatic chamber 3 . Therefore, in the test apparatus 1 of this embodiment, the length dimension of the shaft portion 34 of the probe 32 is increased. That is, in the test apparatus 1, the heavier probes 32 are increased.

Even in such a case, since the probe 32 is supported by the indenter 21 by being suspended from the indenter 21 , application of force for supporting the probe 32 to the load cell 14 is suppressed. As a result, the test apparatus 1 can detect the test force F acting on the test piece TP with high accuracy even when the displacement detector 40 including the long probe 32 is used. .

Furthermore, since the displacement detector 40 is of a contact type, even if it is installed with a predetermined distance from the test piece TP, the displacement detector 40 is more sensitive than, for example, a non-contact displacement detector. The test force F acting on the test piece TP can be detected with high accuracy.
As described above, the test apparatus 1 of the present embodiment can be used, for example, for the method of determining plastic bending properties specified in JIS_K7161 and the grade of the extensometer verification method used in the axial test specified in Grade 1 of JIS_B7741. It is possible to detect the test force F acting on the test piece TP with an accuracy that satisfies the first grade.

The control unit 4 takes in the test force data from the load cell 14 and the data from the displacement detector body 42 and executes data processing. By such processing such as calculation in the control unit 4, the test apparatus 1 obtains the test force F (bending load) on the test piece TP and the deflection of the test piece TP.

[3. effect]
As described above, according to the present embodiment, the test apparatus 1 performs a test for detecting the amount of displacement caused by applying the test force F to the test piece TP. The test apparatus 1 includes an indenter 21 provided on a crosshead 10 that is moved by a load mechanism 12 to apply a test force F to one surface of the test piece TP, and an indenter 21 provided on the crosshead 10 to apply the test force F to the test piece TP. and a load cell 14 for detecting F. In addition, the test apparatus 1 includes a probe 32 arranged at a position facing the indenter 21 with the test piece TP therebetween, and a displacement of the test piece TP caused by applying a test force F from the amount of movement of the probe 32. A displacement detector 40 that detects the amount, and a spring member 50 that connects the probe 32 and the indenter 21 and urges the probe 32 to contact the indenter 21 with the test piece TP therebetween. .

According to this, the probe 32 is supported by the indenter 21 by being suspended from the indenter 21 , so that the force for supporting the probe 32 is suppressed from being applied to the load cell 14 . Therefore, the test apparatus 1 can detect the test force F acting on the test piece TP with higher accuracy.

Further, according to the present embodiment, the displacement detector 40 includes a spindle 44 that moves along with the movement of the probe 32, and the displacement of the test piece TP generated by applying the test force F from the movement amount of the spindle 44. Detect displacement. The spindle 44 may then move vertically downward when the test force F is applied to the test piece TP.

According to this, the force for supporting the spindle 44 is suppressed from being applied to the displacement detector main body 42 . Therefore, the test apparatus 1 can detect the deflection of the test piece TP with higher accuracy.

Further, according to the present embodiment, the constant temperature bath 3 in which the test piece TP, the indenter 21 and the probe 32 are housed may be provided, and the displacement detector 40 may be provided outside the constant temperature bath 3 .

According to this, it is possible to suppress the temperature of the constant temperature bath 3 from acting on the displacement detector 40 . Therefore, the test apparatus 1 can detect the deflection of the test piece TP with higher accuracy.

Further, according to this embodiment, the indenter 21 and the probe 32 may be connected by the spring member 50 .

According to this, in the test apparatus 1, the indenter 21 and the probe 32 can be easily separated from each other, and the test piece TP can be clamped. In addition, the test apparatus 1 can easily sandwich various test pieces TP having different thicknesses.

[4. Other embodiments]
The above-described embodiment is an example of one aspect of the present invention, and can be arbitrarily modified and applied without departing from the scope of the present invention.

In the above-described embodiment, the indenter 21 is provided with the connecting member 25 , but the connection member 25 may be provided in the load cell 14 without being limited to this.

In addition, in the above-described embodiment, the spring member 50 is used as the biasing member. There may be.

It will be appreciated by those skilled in the art that the exemplary embodiments and variations described above are specific examples of the following aspects.

(Section 1)
A test apparatus according to one aspect is a test apparatus that performs a test for detecting a displacement amount generated by applying a test force to a test piece, provided on a crosshead that moves by a load mechanism, and on one surface of the test piece an indenter for applying a test force; a load detector provided on the crosshead for detecting the test force applied to the test piece; and a position facing the indenter across the test piece. A probe, a displacement detector that detects the amount of displacement of the test piece caused by applying a test force from the amount of movement of the probe, the probe and the indenter are connected, and the test piece is connected to the indenter. and an urging member that urges the probe so as to abut against it.

According to the test apparatus of the first aspect, the probe is supported by the indenter by being suspended from the indenter, so that the load cell is restrained from being subjected to a force for supporting the probe. Therefore, the test apparatus can detect the test force acting on the test piece with higher accuracy.

(Section 2)
2. The test apparatus according to claim 1, wherein the displacement detector includes a spindle that moves with the movement of the probe, and displacement of the test piece caused by application of a test force from the amount of movement of the spindle Detecting a volume, the spindle may move along a vertical downward direction as a test force is applied to the specimen.

According to the test apparatus of the second aspect, since the probe is supported by the indenter by being suspended from the indenter, application of force for supporting the probe to the load cell is suppressed. Therefore, the test apparatus can detect the test force acting on the test piece with higher accuracy.

(Section 3)
The test apparatus according to item 1 or 2, further comprising a constant temperature bath containing the test piece, the indenter, and the probe, wherein the displacement detector may be provided outside the constant temperature bath. good.

According to the test apparatus of the third aspect, it is possible to suppress the temperature of the constant temperature bath from acting on the displacement detector. Therefore, the test apparatus can detect the deflection of the test piece with higher accuracy.

(Section 4)
In the test apparatus according to any one of items 1 to 3, the biasing member may be a spring member.

According to the testing device described in item 4, the indenter and the probe can be easily separated from each other, and the test piece can be sandwiched between them. In addition, the test apparatus can easily clamp various test pieces having different thicknesses.

1 test apparatus 2 test apparatus body 3 constant temperature bath 10 crosshead 12 load mechanism 14 load cell (load detector)
15 Displacement sensor 21 Indenter 30 Displacement detector 32 Probe 34 Shaft 36 Tip 38 Connecting member 40 Displacement detector 42 Displacement detector body 44 Spindle 47 Moving body 50 Spring member F Test force TP Test piece

Claims (4)

In a test device that performs a test that detects the amount of displacement caused by applying a test force to a test piece,
an indenter provided on a crosshead that is moved by a load mechanism to apply a test force to one surface of the test piece; a load detector provided on the crosshead for detecting the test force applied to the test piece;
a probe disposed at a position facing the indenter with the test piece sandwiched therebetween;
a displacement detector that detects the amount of displacement of the test piece caused by applying a test force from the amount of movement of the probe; a biasing member that biases the probe into abutment;
test equipment. The displacement detector includes a spindle that moves with the movement of the probe, detects the amount of displacement of the test piece caused by applying the test force from the amount of movement of the spindle,
the spindle moves vertically downward when a test force is applied to the test piece;
The test device according to claim 1. A constant temperature bath containing the test piece, the indenter, and the probe,
The displacement detector is provided outside the constant temperature bath,
3. The testing device according to claim 1 or 2. The biasing member is a spring member,
4. The testing device according to claim 1.

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