JP2004340655A - Rockwell hardness testing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a Rockwell hardness testing machine capable of investigating the relation between the penetration quantity and force of a penetrator easily and accurately. <P>SOLUTION: The Rockwell hardness testing machine has a spring displacement quantity sensor 64 for detecting the force, which is produced in a load arm operating part 6 and transmitted to the penetrator 3 through a load arm 4, on the basis of the spring displacement quantity of a leaf spring 7 and an arm position sensor 8 for measuring the displacement quantity of the penetrator when the penetrator, to which the force is transmitted, is pushed in the sample placed on a sample stand 5. The spring displacement quantity and penetrator displacement quantity are synchronously sampled and the strain component of a machine body including the sample stand produced according to the force transmitted through the penetrator is connected from the measured penetrator displacement quantity, and the force calculated on the basis of the spring displacement quantity and the penetrator displacement quantity sampled and corrected in synchronous relation to the spring displacement quantity are outputted to a display device 11. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a Rockwell hardness tester.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there is known a Rockwell hardness tester that forms a dent by applying a test force to a sample surface by an indenter and evaluates the hardness of the sample from the depth of the dent (for example, Patent Document 1 and the like). ).
In the Rockwell test, first, the sample is held in a state where an initial test force F0 is applied, and then a pressing force is gradually applied to the indenter to finally press the indenter against the sample with the test force F1. Thereafter, the test force F1 is removed from the indenter to return to the initial test force F0, and the indentation depth of the indenter into the sample at this time is measured.
Specifically, based on the difference between the indentation depth h0 of the indenter with respect to the sample at the initial test force F0 and the indentation depth h1 when the test force F1 is removed and returned to the initial test force F0, the Rockwell hardness HRC (C (For scale).
[0003]
[Patent Document 1]
JP 2000-105182 A
[Problems to be solved by the invention]
In the Rockwell hardness test, there is a need to investigate the relationship between the indentation penetration amount and the force in order to evaluate not only the final Rockwell hardness but also the material properties.
However, in the case of the conventional Rockwell hardness tester, it has been difficult to obtain data on the relationship between the intrusion amount of the indenter and the force in real time. Attempting to do this would be more expensive and costly than installing a load cell in a Rockwell hardness test to capture analog force data and indentation penetration data from a linear gauge simultaneously using a sampling device. There was a problem.
[0005]
Also, when a force is applied to the indenter, the body of the Rockwell hardness tester is distorted, so the value obtained from the linear gauge is a value in which the amount of indentation and the amount of body distortion are mixed, and the amount of indentation It was difficult to find exactly.
[0006]
An object of the present invention is to provide a Rockwell hardness tester capable of easily and accurately examining a relationship between an indenter penetration amount and a force.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 uses a Rockwell hardness tester (1), for example, as shown in FIGS.
A force generating unit (for example, a load arm operating unit 6) for generating a force,
A force transmitting unit (for example, a load arm 4) for transmitting a force generated by the force generating unit to the indenter (3);
An elastic member (for example, a leaf spring 7) that is elastically deformed by a force generated by the force generating unit;
An elastic displacement amount detecting means (for example, a spring displacement amount sensor 64) for detecting an elastic displacement amount of the elastic member;
Force calculating means (for example, CPU 93) for calculating a force acting on the indenter based on a detection result of the elastic displacement amount detecting means;
Indenter displacement measuring means (for example, arm position sensor 8) for measuring the displacement of the indenter when the indenter to which the force is transmitted is pushed into the sample placed on the sample stage;
Sampling means (for example, CPU 93) for synchronously sampling the elastic displacement amount detected by the elastic displacement amount detecting means and the indenter displacement amount measured by the indenter displacement measuring means;
From the indenter displacement measured by the indenter displacement measuring means based on the force calculated by the force calculating means, a distortion component of the body including the sample stage caused by the force transmitted via the indenter is calculated. Body distortion correction means (for example, CPU 93, etc.) for correcting
The force calculated by the force calculating means based on the elastic displacement amount sampled by the sampling means, and the correction by the body distortion correcting means based on the indenter displacement amount sampled in synchronization with the elastic displacement amount. Output control means (for example, the CPU 93) for outputting the indenter displacement to the output means (for example, the display device 11).
[0008]
According to the first aspect of the present invention, the force transmitted to the indenter is calculated based on the amount of elastic deformation of the elastic member, so that the test force can be measured at low cost without using an expensive device such as a load cell. be able to.
Further, since the force based on the elastic displacement amount and the indentation penetration amount synchronously sampled by the sampling means are output to the output means, the relationship between the force and the indentation penetration amount can be easily investigated.
Further, based on the force calculated by the force calculating means, the body distortion including the sample stage caused by the force transmitted through the indenter is measured by the body distortion correcting means by the indenter displacement measuring means. Since the displacement is corrected from the displacement, the more accurate relationship between the force and the indentation penetration can be obtained.
[0009]
The invention according to claim 2 is a hardness tester according to claim 1,
The fuselage distortion correction means,
A storage unit (for example, a storage unit) that stores a force calculated by the force calculation unit and a body distortion amount measured by the indenter displacement amount measurement unit and generated according to a force transmitted to the sample via the indenter. 94)
And a correcting unit (for example, a CPU 93) that reads out the body distortion amount corresponding to the force calculated by the force calculating unit from the storage unit when the indenter displacement amount is measured, and corrects the indenter displacement amount. Features.
[0010]
According to the second aspect of the present invention, it is needless to say that the same effect as that of the first aspect is obtained. In particular, the force transmitted to the sample via the indenter measured by the indenter displacement amount measuring means. Is stored in the storage means, and the indenter displacement measured by the indenter displacement measuring means is corrected by the correcting means, so that the indenter displacement is corrected based on the previously measured body distortion. Is performed, and more accurate correction can be performed.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing a main configuration of a hardness tester according to the present embodiment.
As shown in FIG. 1, a hardness tester 1 includes a body 2, a load arm 4 which is rotatably supported by the body 2, and has a free end to which an indenter 3 is attached, as a force transmitting section, and an indenter. 3 and a sample table 5 on which the sample S is mounted, and a sample arm 5 provided below the load arm 4 for rotating the free end side of the load arm 4 to form an indentation on the sample surface. A load arm operating section 6 as a force generating section for applying a pressing force, a leaf spring 7 as an elastic member for transmitting a force generated when the load arm operating section 6 operates to the load arm 4, and an indenter 3. An arm position sensor 8 as an indenter penetration amount measuring means for measuring the depth of the formed indentation.
[0012]
The hardness tester 1 further includes a hardness calculator 9 (see FIG. 2) that calculates the hardness of the sample S based on the depth of the indentation measured by the arm position sensor 8.
[0013]
Further, the hardness tester 1 is calculated by an input device (not shown) for inputting test conditions such as a target indentation force and a load speed, a test condition input screen (not shown), and a hardness calculator 9. And a display device 11 (see FIG. 3) as an output unit for outputting hardness.
The input device (not shown) and the display device may be detachably attached to the hardness tester 1.
[0014]
The body 2 includes a load arm operating unit 6 and an electrical unit 21 serving as a drive source of the load arm operating unit 6 therein. The load arm 4 is rotatably supported on the body 2 by a cruciform spring 41 or a rolling bearing, and the indenter 3 is detachably attached to a free end. The load arm 4 is integrated with the leaf spring 7. A groove 7a is formed along the longitudinal direction between the leaf spring 7 and the load arm 4, and the tip of the groove 7a on the indenter 3 side is open.
[0015]
The sample stage 5 is provided with a square screw 51 on its lower surface, and is attached to the body 2 by the square screw 51 so as to be vertically movable. Further, an automatic brake mechanism 52 for automatically stopping the sample stage 5 when the sample S comes into contact with the indenter 3 is also provided.
The load arm operating section 6 includes a servomotor 61 as an electric operating means, a ball screw 62, and a fixing jig 63 attached to the tip of the ball screw 62 and fixed to the leaf spring 7. Therefore, when the servomotor 61 is driven to move the ball screw 62 up and down, the load arm 4 integrated with the leaf spring 7 rotates. The fixing jig 63 connects the load arm 4 and the load arm operating section 6, and causes misalignment between the axis of the leaf spring 7 and the axis of the load arm operating section 6 due to the rotation of the load arm 4 and the elastic deformation of the leaf spring 7. For example, a thin plate, a wire such as a piano wire, a combination of a knife edge and a cross spring, a universal joint, or the like is used alone or in combination.
[0016]
Further, the load arm operating section 6 includes a spring displacement amount sensor 64 attached to the load arm 4 and the leaf spring 7 and serving as an elastic displacement amount measuring means for detecting an opening amount thereof, that is, a spring deformation amount of the leaf spring 7. ing.
[0017]
The spring displacement sensor 64 is composed of, for example, a displacement sensor unit (linear scale) that optically reads a glass scale. The downward movement of the ball screw 62 causes the amount of opening of the groove 7 a between the leaf spring 7 and the load arm 4 to be increased. The amount of spring displacement is detected, and the detected amount of spring displacement is output to the hardness calculator 9.
Here, the amount of spring displacement is proportional to the pressing force of the indenter 3 or the test load applied to the sample S.
[0018]
The arm position sensor 8 includes, for example, a displacement sensor unit (linear scale) that optically reads a glass scale, similarly to the spring displacement sensor 64, and measures the amount of vertical movement of the load arm 4. The measured arm displacement is output to the hardness calculator 9.
Here, the amount of movement of the load arm 4 in the vertical direction is proportional to the amount of the indenter 3 entering the sample S.
[0019]
As shown in FIG. 3, the hardness calculation unit 9 includes an amplifier 91, an A / D converter 92, a CPU (Central Processing Unit) 93, a storage unit 94, and the like.
[0020]
The amplifier 91 amplifies the spring displacement signal detected by the spring displacement sensor 64 and the arm displacement signal detected by the arm position sensor 8, and outputs the amplified signal to the A / D converter 92. The A / D converter 92 A / D converts the amplified spring displacement signal and the arm displacement signal and outputs the signal to the CPU 93.
Here, the A / D converted spring displacement signal is spring displacement data, and the arm displacement signal is indenter penetration data.
[0021]
The CPU 93 expands programs and data stored in the storage unit 94 in a RAM area 941 in the storage unit 94, executes processing according to the programs, and temporarily stores an execution result in the RAM area 941.
Specifically, the CPU 93 executes a sampling program 943 incorporated in the storage unit 94 as a sampling unit, so that the spring displacement measured by the spring displacement sensor 64 and the indenter measured by the arm position sensor 8 are measured. The displacement amount is synchronously sampled at a predetermined sampling frequency.
Further, the CPU 93, as a force calculating means, calculates a force acting on the indenter 3 by executing a force calculating program 944 incorporated in the storage unit 94 based on the input spring displacement data.
[0022]
Further, as correction means, the CPU 93 corrects the indenter penetration amount according to the machine distortion correction program 945 built in the storage unit 94 based on the calculated force data acting on the indenter 3 and the calculated indentation penetration amount data. That is, the CPU 93 reads the body distortion amount corresponding to the calculated force data from the body distortion correction data 942 stored in the storage unit 94, and corrects the indenter penetration amount.
[0023]
Further, the CPU 93 outputs, as output control means, the force calculated based on the sampled spring displacement amount and the indenter displacement amount corrected based on the indenter displacement amount sampled in synchronization with the spring displacement amount. By executing the display control program 946 stored in the storage unit 94, predetermined output data is created, and the output data is output to the display device 11.
[0024]
Further, the CPU 93 calculates the hardness of the sample according to the hardness calculation program 947 stored in the storage unit 94 based on the corrected indenter penetration amount.
Further, the CPU 93 processes the calculated hardness data into data in a predetermined output format and outputs the processed data to the display device 11.
[0025]
The storage unit 94 includes a RAM area 941 as a work area of the CPU 93, a body distortion correction data 942, a sampling program 943, a force calculation program 944, a body distortion correction program 945, a display control program 946, a hardness calculation program 947, and the like. Is provided, and functions as storage means.
The display device 11 includes, for example, a display screen configured of a CRT (Cathode Ray Tube), a liquid crystal, or the like.
[0026]
Next, a method of creating the body distortion correction data will be described.
First, a strain measurement indenter (not shown) having an obtuse tip is attached to the free end of the load arm 4.
Next, a distortion measurement sample (not shown) is placed on the sample table 5. At least the measurement part and its periphery are made of cemented carbide steel, and the strain measurement sample is designed so that no indentation is formed on the surface with a force within a test force setting range (for example, 0.098 mN to 980.7 mN). Has become.
[0027]
Next, the force when the force within the test force setting range is continuously changed by the load arm operating unit 6 is measured by the spring displacement sensor 64, and the arm is synchronized with the force measurement by the spring displacement sensor 64. The body distortion is measured by the position sensor 8.
After the measured force and body distortion are temporarily stored in a RAM area 941 of the storage unit 94, the CPU 93 creates body distortion correction data in which the force and body distortion stored in the RAM area 941 are associated. Then, the created machine distortion correction data is stored in the storage unit 94.
[0028]
It should be noted that a correction formula is calculated from some measured body distortion data by a correction formula calculation program (not shown), and body distortion correction data is created from the value obtained from the calculated correction formula and stored in the storage unit 94. May be.
[0029]
Next, the operation of correcting the indentation penetration amount and the operation of calculating the hardness by the hardness tester 1 will be described.
First, body distortion correction data is created by the above-described body distortion correction data creation method, and the created body distortion correction data is stored in the storage unit 94.
Next, the indenter 3 for measuring the amount of indentation having a sharp tip is attached to the free end 4a of the force transmission lever 4, and the test sample S is placed on the sample table 20a.
[0030]
Subsequently, a predetermined current is applied to the force coil 21 to lower the load arm 4, and a predetermined force is transmitted to the sample S via the indenter 3.
At this time, the force acting on the indenter 3 is measured by the spring displacement sensor 64, and the measurement result of the spring displacement signal is output to the CPU 93 via the amplifier 91 and the A / D converter 92 at a predetermined sampling frequency. You.
In addition, the displacement of the indenter 3 is measured by the arm position sensor 8 in synchronization with the force measurement, and the arm displacement amount signal as the measurement result is output to the CPU 93 via the amplifier 91 and the A / D converter 92.
The CPU 93 temporarily stores the sampled spring displacement data and arm displacement data in the RAM area 941 of the storage unit 94 in association with each other.
Further, the CPU 93 calculates a force based on the sampled spring displacement amount data, and temporarily stores the calculated force data in the RAM area 941 of the storage unit 94.
[0031]
Next, the CPU 93 reads the body distortion amount corresponding to the force based on the spring displacement data from the body distortion data in the storage unit 94 by executing the body distortion correction program, and inputs the input arm displacement data (apparent displacement data). The intrusion amount read from the in-body distortion data is subtracted from the indentation intrusion amount data to calculate a true indentation amount from which the amount of the in-body distortion has been removed and stored in the RAM area 941.
[0032]
Further, the CPU 93 outputs the force based on the spring displacement stored in the RAM area 941 and the indenter penetration corrected for the body distortion to the display device 11 in the form of a graph.
Specifically, for example, as shown at the bottom of FIG. 3, a graph is displayed in which the horizontal axis represents the indentation position (μm) of the indenter and the vertical axis represents the force (N). In this graph, it can be seen that the maximum penetration of the indenter is about 10 μm and the Rockwell depth is about 8 μm. Further, for example, it is also understood that the material characteristics such as the amount of penetration with respect to the force are larger in the high load region than in the low load region.
[0033]
Next, the CPU 93 calculates hardness data by executing a hardness calculation program based on the calculated true indenter penetration amount, and outputs the calculated hardness data to the display device 11.
[0034]
According to the hardness tester 1 described above, the force transmitted to the indenter 3 is calculated based on the amount of spring deformation of the leaf spring 7, so that the force can be reduced at low cost without using an expensive device such as a load cell. Can be measured.
In addition, since the force based on the amount of spring displacement and the amount of indenter penetration, which are synchronously sampled, are continuously output to the display device 11, it is possible to easily investigate the material characteristics based on the relationship between the force and the amount of indenter penetration. .
Further, based on the measured force, the amount of distortion of the body 2 including the sample stage 5 caused by the force transmitted via the indenter 3 is corrected from the displacement measured by the arm position sensor 8. Therefore, a more accurate relationship between the force and the indenter penetration amount can be obtained.
[0035]
In addition, the amount of body distortion generated according to the force transmitted to the sample S via the indenter 3 measured by the arm position sensor 8 is stored in the storage unit 94, and the indenter displacement measured by the arm position sensor 8 is corrected. Accordingly, the indenter displacement amount is corrected based on the previously measured body distortion amount, and more accurate correction can be performed.
[0036]
In the above-described embodiment, a linear scale is used as each of the spring displacement sensor 64 and the arm position sensor 8. However, the present invention is not limited to this. For example, a capacitor pick (charge capacity displacement sensor), an LVDT (operation Transformer), an electric micrometer or the like may be used.
Further, instead of the leaf spring 7, a coil spring, an assembled leaf spring, an integrated spring, rubber, or the like may be used. Further, when a relatively large load is applied to the sample S, the leaf spring 7 may be a support beam at both ends.
[0037]
【The invention's effect】
According to the first aspect of the present invention, since the force transmitted to the indenter is calculated based on the amount of elastic deformation of the elastic member, the force can be measured at low cost without using an expensive device such as a load cell. Can be.
Further, since the force based on the elastic displacement amount and the indentation penetration amount synchronously sampled by the sampling means are output to the output means, the relationship between the force and the indentation penetration amount can be easily investigated.
Furthermore, based on the force measured by the force measuring means, the body distortion including the sample stage caused by the force transmitted via the indenter is measured by the indenter displacement measuring means by the body distortion correcting means. Since the displacement is corrected from the displacement, the more accurate relationship between the force and the indentation can be obtained.
[0038]
According to the second aspect of the present invention, it is needless to say that the same effect as that of the first aspect is obtained. In particular, the force transmitted to the sample via the indenter measured by the indenter displacement amount measuring means. Is stored in the storage means, and the indenter displacement measured by the indenter displacement measuring means is corrected by the correcting means, so that the indenter displacement is corrected based on the previously measured body distortion. Is performed, and more accurate correction can be performed.
[Brief description of the drawings]
FIG. 1 is a side view showing a configuration of a main part of a hardness tester to which the present invention is applied.
FIG. 2 is a block diagram illustrating a main configuration of a hardness calculator illustrated in FIG. 1;
FIG. 3 is a diagram showing a display example on a display device.
[Explanation of symbols]
1 Hardness tester 2 Body 3 Indenter 4 Load arm (force transmission unit)
5 Sample table 6 Load arm operating section (force generating section)
7 leaf spring (elastic member)
8. Arm position sensor (indenter displacement measurement means)
9 Hardness calculator 11 Display device (output means)
91 amplifier 92 A / D converter 93 CPU (sampling means, force calculation means, body distortion correction means,
Correction means, output control means)
94 storage unit (storage means)
S sample

Claims (2)

A force generating unit for generating a force,
A force transmitting unit that transmits the force generated by the force generating unit to the indenter,
An elastic member that is elastically deformed by a force generated by the force generating unit;
Elastic displacement amount detecting means for detecting an elastic displacement amount of the elastic member,
Force calculation means for calculating a force acting on the indenter based on a detection result of the elastic displacement amount detection means,
The indenter to which the force has been transmitted, an indenter displacement amount measuring means for measuring the displacement amount of the indenter when being pushed into the sample placed on the sample stage,
Sampling means for synchronously sampling the elastic displacement amount detected by the elastic displacement amount detecting means and the indenter displacement amount measured by the indenter displacement measuring means,
Based on the force calculated by the force calculating means, the amount of distortion of the body including the sample stage caused by the force transmitted through the indenter is calculated by the indenter displacement measured by the indenter displacement measuring means. Body distortion correction means for correcting from
The force calculated by the force calculating means based on the elastic displacement amount sampled by the sampling means and the correction by the body distortion correcting means based on the indenter displacement amount sampled in synchronization with the elastic displacement amount. And an output control means for outputting the obtained indenter displacement amount to an output means. The hardness tester according to claim 1,
The fuselage distortion correction means,
A storage unit that stores the force calculated by the force calculation unit and the body distortion amount measured by the indenter displacement amount measurement unit and generated in accordance with the force transmitted to the sample via the indenter in association with each other. ,
When measuring the indenter displacement amount, a correction means for reading out the body distortion amount corresponding to the force calculated by the force calculating means from the storage means and correcting the indenter displacement amount. testing machine.

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