JP2000046708A - Material testing machine - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a material testing machine that enables highly accurate load calibration when performing load calibration using a weight (weight). SOLUTION: A weight (31) is set in a material testing machine, a standard gravitational acceleration (g _m ) is input to the material testing machine,
The gravity value engraved on the weight (31) is input to the material testing machine, and the gravitational acceleration ( _gl ) at the place where the material testing machine is installed is input to the material testing machine. ) Is measured, and the standard gravitational acceleration (g _m ) input, the gravitational value carved on the input weight, the gravitational acceleration (g _l ) at the material testing machine installation location, and the load cell are input. Calibrate the load with the weight from the value measured by.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a material testing machine for applying a tensile load or a compressive load to a test piece to test the material properties of the test piece.

[0002]

2. Description of the Related Art There is known a material testing machine for applying a tensile load or a compressive load to a test piece to test the material properties of the test piece. This material testing machine was obtained by a mechanism for holding a test piece, a mechanism for pulling or applying pressure to the test piece via the held mechanism, a load cell for detecting the tensile load and the compressive load, and a load cell. A control device for processing values is provided.

In order to accurately measure a tensile load and a compressive load, load calibration is required in a material testing machine. As a method of the load calibration, a method using a loop power detector utilizing the bending force of a power detector and a method using a weight (weight) for load calibration are known. In the method using a load calibration weight, a reference load calibration weight is set on the test piece holding mechanism, the gravity due to the weight is measured with a load cell, and the measured value is the gravity value written on the weight. (For example, 100 N (Newton)). The gravity value (weight) of the weight is generally set based on the standard gravitational acceleration (9.88065 m / s ² ). The gravity is a force due to the gravitational acceleration, and is represented by a product of the mass of the object and the gravitational acceleration. Weight and weight are the magnitude of this gravity and are different from mass. Further, the load is synonymous with the applied force or the applied force.

[0004]

In the method using the weight for load calibration, the gravitational acceleration at the place where the material testing machine is installed is generally different from the standard gravitational acceleration due to a geographical difference or the like. Therefore, when the load calibration is performed by the above-described method, accurate calibration cannot be performed, and a problem that a highly accurate material test cannot be performed has occurred.

[0005] It is an object of the present invention to provide a material testing machine capable of performing high-accuracy load calibration by eliminating an error due to a difference in gravitational acceleration when carrying out load calibration using a weight (weight). It is in.

[0006]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described below with reference to FIGS. In order to achieve the above object, a material testing machine according to the present invention includes a load mechanism (11 to 18, 21, 22) for applying a load to a specimen (TP);
Specimen (T) by loading mechanism (11-18, 21, 22)
Load detecting means for detecting a load applied to P);
The present invention is applied to a material testing machine having a calibrating means (1) for calibrating a load value detected by the load detecting means (23) using a gravitational value acting on a calibration weight (31). And
First storage means (4) for storing the gravitational acceleration at the material testing machine installation point; and a reference gravitational acceleration or a calibration weight (3) at which the calibration weight (31) generates a predetermined gravity value.
Second calibration means (4) for storing the mass value of (1), wherein the calibration means (1) is based on the gravitational acceleration at the material testing machine installation point and the reference gravitational acceleration or when the material testing machine is installed. The load calibration is performed by correcting the gravity value acting on the calibration weight (31) based on the gravitational acceleration of the point and the mass value of the calibration weight.

In the section of the means for solving the above-mentioned problems, the description is made in correspondence with the drawings of the embodiments for easy understanding, but the present invention is not limited to the embodiments.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment FIG. 1 is a diagram showing a configuration of a material testing machine according to the present invention. On the fixed table 11, a pair of left and right screw rods 12,
13 is erected, and a yoke 14 is laid horizontally above the screw rods 12 and 13. Each of the screw rods 12 and 13 and a pair of nuts (not shown) provided on the left and right sides of the crosshead 15 are screwed together, so that the crosshead 15 is supported by the screw rods 12 and 13. The motor 16 disposed in the fixed table 11 is connected via a motor driver 17 to
It is connected to a control device 1 that controls the operation of the material testing machine.
The control device 1 is composed of a microcomputer and its peripheral circuits. The output shaft of the motor 16 is
Are connected to the screw rods 12 and 13 through the shaft. A pulse encoder 19 is connected to the output shaft of the motor 16, and the pulse encoder 19 is connected to the control device 1 via a counter 20.

An upper grip 21 and a lower grip 22 for holding the test piece TP are attached to the lower surface of the crosshead 15 and the upper surface of the fixed table 11 so as to face each other. And the test piece TP is held by the lower grip 22. Then, as the motor 16 rotates in a predetermined direction based on a control signal from the control device 1, the screw rod 1 is transmitted through the transmission device 18.
2 and 13 rotate in the same direction, and these screw rods 12 and 13 rotate.
The crosshead 16 screwed to the ascends. Thereby, a tensile load is applied to the test piece TP held by the upper grip 21 and the lower grip 22. At this time, the tensile load detected by the load cell 23 attached to the upper part of the crosshead 15 is transmitted to the encoder 1 via the head amplifier 24 and the A / D converter 25.
9 together with the rotation amount of the motor 16 detected by the control unit 1
Is input to

The control device 1 includes a display device 2 for displaying operation contents and load values and various analysis contents as measurement results, an input device 3 for inputting instructions and the like from an operator, and various operation results and data. A memory 4 for storing is connected. The control device 1 calculates an accurate load value by multiplying the load value input from the load cell 23 via the head amplifier 24 and the A / D converter 25 by a load calibration coefficient, stores the load value in the memory 4, and performs various analysis. Used for Further, the value is displayed on the display device 2 as necessary.

Next, a load calibration method in the material testing machine according to the first embodiment will be described. First, the principle content will be described. In the present embodiment, a weight (weight) is used for the load calibration, and the load calibration is performed using the gravity caused by the weight. The weight for load calibration is manufactured by being accurately calibrated as a weight having a predetermined gravity value (weight, weight). The predetermined gravity value is a gravity value based on a standard gravity acceleration (reference gravity acceleration). This gravitational acceleration is g
_m (m / s ² ), and the mass of the weight having a predetermined gravity value is M
(Kg), the force due to this weight, that is, gravity F
(N: Newton) is represented by the following equation. F = M · g _m . . . . . (1)

A predetermined gravity value F and a standard gravity acceleration g
_{When m} is known, the mass M of the weight is known from equation (1). The mass, gravity value, and standard gravitational acceleration of the weight are engraved on the surface of the weight or attached to a data sheet and presented. For example, the weight A has a mass of 10.197 kg, a gravitational value of 100 N, and a gravitational acceleration of 9.8.
07 m / s ² data is stamped and presented. The gravity acceleration 9.807 m / s ² is a standard gravity acceleration.

The weight of the material testing machine is calibrated using the weight. FIG. 2 is a side view of an example of a weight for load calibration. FIG. 2 shows a weight (weight) 31 and a hook 32, but in the case of a weight in the present embodiment, the hook 32 is not included, and the hook 32 is zero-adjusted as a tare. The weight 31 is held by the upper grip 21 of FIG. 1 via the hook 32 and an actual load is applied to the load cell 23. If the gravitational acceleration at the place (point) where the material testing machine is installed shows the same value as the standard gravitational acceleration, the force of the gravitational value carved on the weight is applied to the load cell. Therefore, calibration (correction) may be performed so that the measured value of the load cell becomes the same value as the gravity value carved on the weight. For example, in the case of the weight A, calibration is performed so that the measured value becomes 100N.

However, if the gravitational acceleration at the place where the material testing machine is installed is different from the standard gravitational acceleration, it will be inaccurate if calibrated to the gravitational value carved on the weight. For example, if the material testing machine has a gravitational acceleration 9.
When it is assumed that the weight A is set in the area of 700 m / s ^2, the weight A is set on the upper grip 21, and the load cell 23 has F = 10.197 × 9.700 = 98.910 (N). . . . . (2) Therefore, in fact, only 98.910 (N) is applied. In this case, if calibration is performed based on the data engraved on the weight A on the assumption that a force of 100 N is applied, an incorrect load measurement will result. Therefore, in this case, calibration is performed so that the measured value becomes 98.910 N. In order to perform this calibration, the control device 1 stores the weight A data of 10.197 kg, a gravity value of 100 N,
Along with 9.807 m / s ² of gravitational acceleration, it is necessary to input and store 9.700 m / s ² of gravitational acceleration at the installation location of the material testing machine.

A control procedure for implementing the load calibration method based on the above concept in a material testing machine will be described below. FIG. 3 is a flowchart illustrating a load calibration control procedure in the material testing machine according to the first embodiment. This processing is executed in the control device 1. This routine starts when a predetermined weight for load calibration is set on the upper grip 21 of the material testing machine, and an instruction to start load calibration is input by the input device 3.

[0016] In step S1, the operator is input to the standard acceleration of gravity, and stores the input acceleration of gravity in the memory 4 as g _m. In step S2, the operator gives the value of the weight (weight), that is, the gravity value (g) carved on the weight.
_m ), and the input value is F
In the memory 4. In step S3, the operator inputs the gravitational acceleration at the place where the material testing machine is installed, and stores the input gravitational acceleration in the memory 4 as _gl . In step S4, the process waits for an instruction from the input device 3 to start measurement, and if there is, the process proceeds to step S5.

In step S5, the output of the load cell 23 is amplified by the head amplifier 24, converted into a digital value by the A / D converter 25, and input.
To memorize. In step S6, Y is obtained from the following equation. Y = (g _l / g _m ) · F (3) The value of Y is the gravitational acceleration g _l at which the material testing machine is installed.
Is the force (actual load, actual gravity) that is actually applied to the load cell 23 by the set weight at the location (1). In step S7, a calibration (correction) coefficient a is obtained from the following equation and stored in the memory 4. a = Y / X (4) This calibration coefficient is used by the material testing machine as a calibration value until a new load calibration is performed. For example, if the value measured by the load cell 23 in a certain tensile test is Z (N), the actual tensile load is calculated as Za · (N) and used for various analyzes of the material test.

In step S8, the load cell 23 is actually
Is displayed on the display device 2. In this case, the following message may be displayed as needed. "The value of weight F (N) is Y (N)
Is measured. " When the weight used for the load calibration is constant and the load calibration is performed periodically, the step S
1 to S3 may be input only once, and the subsequent calibration may be started from step S4. Alternatively, when the calibration is performed by changing only the type of weight, steps S1 and S3 may be input only once, and then steps S2 and S4 and subsequent steps may be executed.

As described above, the standard gravitational acceleration,
By inputting the gravity value of the weight (weight) carved on the weight and the gravitational acceleration at the place where the material testing machine is installed to the material testing machine, the actual force applied to the load cell can be calculated. Load calibration can be performed.

Second Embodiment FIG. 4 is a flowchart showing a control procedure for load calibration in a material testing machine according to a second embodiment. In the second embodiment, only the content of the control procedure is different, and the configuration of the material tester is the same as that of FIG.

Hereinafter, the flowchart of FIG. 4 will be described. In step S11, the operator is caused to input the gravitational acceleration at the place where the material testing machine is installed, and the input gravitational acceleration is stored as _gl in the memory 4. In step S12, the operator inputs the value of the mass of the weight (weight), and stores the input value as M in the memory 4. Step S1
In step 3, the operator waits for an instruction to start measurement by the input device 3, and if there is an instruction, the process proceeds to step S14.

In step S14, the output of the load cell 23 is amplified by the head amplifier 24, converted into a digital value by the A / D converter 25 and input, and the value is stored in the memory 4 as X. In step S15, Y is obtained from the following equation. Y = M · g ₁ (5) The value of Y is the gravitational acceleration g ₁ at which the material testing machine is installed.
Is the force (actual load) that is actually applied to the load cell 23 by the set weight at the location. In step S16, a calibration (correction) coefficient a is obtained from the following equation and stored in the memory 4. a = Y / X (6) This calibration coefficient is used by the material testing machine as a calibration value until a new load calibration is performed in the same manner as in the first embodiment. In step S17, the actual load value Y actually applied to the load cell 23 is displayed on the display device 2. In this case, the following message may be displayed as needed. "The weight of mass M is measured as Y (N) in this region." When the weight used for the load calibration is always the same and the calibration is performed periodically, as in the first embodiment, steps S11 and S12 are input only once, and thereafter, step S13 is performed. You may be made to start from. Alternatively, when only the type of weight is changed, step S11 may be input only once, and then step S12 and subsequent steps may be executed.

As described above, by inputting the mass of the weight and the gravitational acceleration at the place where the material testing machine is installed to the material testing machine, the actual force applied to the load cell by the weight can be calculated. Accurate load calibration can be performed.

The calibration coefficients calculated in the first and second embodiments are also used as the calibration coefficients for the compressive load when the load cell exhibits similar characteristics to the tensile load and the compressive load. it can. In addition, even if the same characteristics are not shown, even if the characteristics show a certain relationship with respect to the tensile load and the compressive load, the coefficient can be used as the calibration factor for the compressive load, considering the certain relationship. it can.

In the first and second embodiments, an example of a material testing machine has been described. However, the present invention is not limited to this. For example, the present invention can be applied to a hardness meter that applies a load to a test piece via an indenter and measures the hardness of the test piece.
That is, the present invention can be applied to the case where the load is calibrated by the weight in all test devices that need to measure the tensile load, the compressive load, and the like.

[0026]

As described above, according to the present invention, since the load calibration using the weight is performed based on the gravitational acceleration at the installation point of the material testing machine, the accurate load calibration using the weight can be performed.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a material testing machine according to a first embodiment.

FIG. 2 is a side view of an example of a weight for load calibration.

FIG. 3 is a flowchart showing a control procedure for load calibration according to the first embodiment;

FIG. 4 is a flowchart illustrating a load calibration control procedure according to the second embodiment;

[Explanation of symbols]

 Reference Signs List 1 control device 2 display device 3 input device 4 memory 11 fixed table 12, 13 screw rod 14 yoke 15 crosshead 16 motor 17 motor driver 18 transmission device 19 pulse encoder 20 counter 21 upper grip 22 lower grip 23 load cell 24 head amplifier 25 A / D converter TP test piece

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Takaaki Mayumi 1 Shiinozu Goshodacho, Kitano-ku, Kyoto-shi F-term in Shimadzu Corporation Shino Plant (reference) 2G061 AA01 AA02 AB01 BA01 BA20 EA01 EA02 EB02 EB05 EC02 EC04 EC06

Claims (1)

[Claims] 1. A load mechanism for applying a load to a specimen, a load detecting means for detecting a load applied to the specimen by the load mechanism, and a gravity acting on a calibration weight by a load value detected by the load detecting means. A material testing machine having calibration means for calibrating using a value, a first storage means for storing a gravitational acceleration at a material testing machine installation point, a reference gravitational acceleration at which the calibration weight generates a predetermined gravitational value, or And a second storage means for storing a mass value of the calibration weight, wherein the calibration means is based on the gravitational acceleration at the material testing machine installation point and the reference gravitational acceleration, or based on the material testing machine installation. A material testing machine, wherein a load calibration is performed by correcting a gravity value acting on the calibration weight based on a gravitational acceleration at a point and a mass value of the calibration weight.