JP4299950B2 - Indentation formation mechanism and hardness tester - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an indentation forming mechanism used in a testing machine that evaluates material properties of a sample based on applying a load to the surface of the sample with an indenter to form an indentation, and a hardness tester equipped with the indentation forming mechanism. About.
[0002]
[Prior art]
Conventionally, a hardness test is known as a testing machine for evaluating the material characteristics of a sample based on applying a load to the surface of the sample with an indenter to form an indentation.
As a load loading mechanism in this conventional hardness tester, for example, the one shown in FIG. 8 is known.
The hardness tester 100 shown in FIG. 8 is a so-called Rockwell hardness tester, and includes a weight 101, a load arm 102, a cam 103, a load shaft 104, an indenter shaft 105, an indenter 106, and the like. An indentation forming mechanism 110 is provided.
According to this indentation forming mechanism 110, a predetermined weight 101 is suspended from the tip of the load arm 102, the load arm 102 is lowered by the rotation of the cam 103, and a predetermined load acts on the load shaft 104. The load acting on the load shaft 104 is transmitted to the indenter 106 via the indenter shaft 105, and the indenter 106 moves downward to form an indentation on the sample placed on the sample stage 107. It is like that.
[0003]
Here, there is a problem that load control by weight, represented by the hardness tester 100, cannot confirm whether the load during formation of the indentation is acting on the sample according to the set value. It was.
In addition, since a force is applied to the sample with a weight, a so-called overshoot occurs in which a force exceeding the target is generated unless the force load speed is reduced by a damper or the like. In addition, there is a problem that even if a damper is used, it is difficult to eliminate a small overshoot.
[0004]
In order to solve this problem, a method of applying load control electrically and applying weight to the sample can be considered. In the case of this electric load control, the load arm is highly rigid for the convenience of control.
[0005]
[Problems to be solved by the invention]
However, in a hardness tester having a highly rigid load arm, impact (step-like force) is likely to be applied to the sample at the moment when the sample is brought into contact with the indenter manually, and the force exceeding the initial test force can be easily applied to the sample. May be added to.
In such a case, there was a problem that the hardness test of the sample could not be performed properly.
[0006]
The present invention has been made in order to solve the above-mentioned problems, and it is easy and accurate to alleviate an impact when contacting an indenter and a sample in an indentation forming mechanism having a highly rigid load arm and a hardness tester. The initial test force is given to the sample.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, the invention according to claim 1 measures the material properties of the sample based on forming an indentation on the sample surface with an indenter (3) as shown in FIGS. An indentation forming mechanism (10) used in a testing machine,
When the sample and the indenter are brought into contact with each other, an impact mitigating means (65: load arm operation control unit, 61: servo motor) that controls movement of one of the indenter and the sample in the same direction as the other,
By reducing the impulse at the time of contact, the impact generated between the sample and the indenter is mitigated.
[0008]
According to the first aspect of the present invention, since the impact relaxation means is provided, the impulse that the indenter gives to the sample at the time of contact between the sample and the indenter can be reduced. That is, since the impact when the indenter contacts the sample is reduced, the problem of exceeding the initial test force at the time of contact can be solved.
[0009]
The invention according to claim 2
The indentation formation mechanism according to claim 1,
The impact relaxation means is
Load control means (65: load arm operation control unit) that calculates a predetermined load applied to the sample in accordance with the displacement of the indenter from a reference position when the sample is in contact with the indenter;
Moving means (61: servo motor) for moving the indenter in the same direction as the sample so as to give the sample a predetermined load calculated by the load control means;
It is characterized by having.
[0010]
According to the second aspect of the invention, since the load control means and the moving means are provided, a load corresponding to the displacement from the reference position of the indenter is given to the sample, and an operator who manually moves the sample is conventionally In the same manner as described above, a predetermined load can be applied to the sample more appropriately by simply operating the handle or the like.
[0011]
The invention described in claim 3
The indentation formation mechanism according to claim 1 or 2,
The impact relaxation means is
A distance detecting means for detecting a distance between the indenter and the sample;
When the indenter and the sample are close to each other by a predetermined distance, one of the indenter and the sample is controlled to move at a predetermined speed in the same direction as the other, and the impulse at the time of contact is reduced.
[0012]
According to the invention of claim 3, since the distance detecting means is provided, one can be moved in the same direction as the other immediately before the sample and the indenter contact each other, and the moment of contact between the sample and the indenter In addition, the impact can be further reduced.
[0013]
The invention described in claim 4 is characterized in that the indentation forming mechanism described in any one of claims 1 to 3 is provided.
[0014]
According to the invention described in claim 4, since the indentation forming mechanism according to any one of claims 1 to 3 is provided, when the sample and the indenter are contacted, the initial test force is not easily exceeded. This improves work efficiency. Moreover, since the initial test force is not exceeded at the time of contact, the reliability with respect to the result of the hardness test is improved.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of an indentation forming mechanism and a hardness tester according to the present invention will be described below in detail with reference to the drawings.
FIG. 1 is a side view showing a main part configuration of a hardness tester according to the present invention, FIG. 2 is a block diagram showing a main part configuration of a load arm movement control unit of the present invention, and FIG. It is a block diagram which shows the principal part structure of the hardness calculation mechanism part which concerns on this invention.
[0016]
A hardness tester 1 shown in FIG. 1 includes a tester main body 2, a load arm 4 rotatably supported by the tester main body 2, and an indenter 3 attached to a free end, and a lower part of the indenter 3. In order to form an indentation on the surface of the sample provided on the test machine body 2 and provided below the sample stage 5 on which the sample s is placed and the load arm 4 and the free end side of the load arm 4 is rotated. An indentation forming mechanism comprising a load arm actuating portion 6 for applying a force for applying a pressing force, and a leaf spring 7 for transmitting the force generated when the load arm actuating portion 6 is actuated to the load arm 4 The arm position sensor 8 includes a unit 10 and measures the depth of the indentation formed by the indenter 3, and the hardness calculation unit 9 calculates the hardness based on the measurement by the arm position sensor 8 (see FIG. 3). ) Etc. It has a mechanism section 20. Moreover, although not shown in figure, the load input part which inputs a setting load is also provided.
[0017]
The testing machine main body 2 includes the load arm operating unit 6 and an electrical unit 21 serving as a drive source for the load arm operating unit 6.
The load arm 4 is rotatably supported on the testing machine main body 2 by a cross spring or a rolling bearing, and an indenter 3 is detachably attached to a free end portion. The load arm 4 is integrated with the leaf spring 7. In the initial state, the load arm 4 is maintained by the servo motor 61 at a position rotated downward by a predetermined amount from the horizontal.
A groove 7a is provided along the longitudinal direction between the leaf spring 7 and the load arm 4, and its tip on the side of the indenter 3 is open.
[0018]
The sample stage 5 is provided with a square screw 51 on its lower surface, and is attached to the testing machine main body 2 by the square screw 51 so as to be movable up and down. Furthermore, an autobrake mechanism 52 that automatically stops the sample stage 5 when the sample s and the indenter 3 come into contact with each other is also provided.
The load arm actuating unit 6 includes a servo motor 61 as a moving 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. Yes. Accordingly, when the servo motor 61 is driven and the ball screw 62 moves up and down, the load arm 4 integrated with the leaf spring 7 is rotated.
The fixing jig 63 connects the load arm 4 and the load arm actuating portion 6, and the axis of the leaf spring 7 and the axis of the load arm actuating portion 6 due to the rotational movement of the load arm 4 and the deformation of the leaf spring 7. For example, a thin plate, a wire such as a piano wire, or a combination of a knife edge and a cross spring, a universal joint, or the like.
[0019]
The operation of the load arm 4 is controlled by a spring displacement sensor 64 that is attached to the load arm 4 and the leaf spring 7 and measures the amount of spring deformation, and the amount of spring deformation measured by the spring displacement sensor 64 is input. The load arm operation control unit 65 as load control means for controlling the operation of the ball screw 62 based on the amount of spring deformation is performed.
The spring displacement sensor 64 includes, for example, a displacement sensor unit (linear scale) that optically reads a glass scale, and the leaf spring 7 and the groove 7 a of the load arm 4 are opened by the downward operation of the ball screw 62. The amount of spring displacement is measured from the amount, and the spring displacement amount signal is A / D converted and then output to the load arm operation control unit 65.
As shown in FIG. 2, the load arm operation control unit 65 includes a servo gain calculation circuit 651, an automatic load calculation circuit 652, a load control circuit 653, a servo gain calculation circuit 654, a target position calculation circuit 655, and a load arm position control circuit. 656, a D / A converter 657, a servo motor drive circuit 658, and the like.
[0020]
The servo gain calculation circuit 651 receives an A / D converted spring displacement amount signal and an arm position signal when an operator brings the indenter 3 and the sample s into contact and gives an initial test force. Then, the servo gain calculation circuit 651 performs control for simulating a state in which a load is gradually applied by a spring from the time when the indenter 3 and the sample s are in contact, that is, after bringing the sample s into contact with the indenter 3, A value for controlling the rotation of the load arm 4 (hereinafter referred to as spring control) so that a load is applied from the indenter 3 to the sample s gradually according to the displacement is calculated.
[0021]
The servo gain calculation circuit 651 receives the A / D converted spring displacement signal and the arm position signal in the process of applying the test force to the sample s, and detects the load change amount and the sample deformation amount change. Calculate the spring constant to determine the initial servo gain (Gain).
Further, the servo gain calculation circuit 651 increases the servo gain when there is no change in error (Err) during a predetermined number of feedback steps, and restores it when the servo gain exceeds a predetermined value. Take control. The determined servo gain is output to the load control circuit 652.
The servo gain calculation circuit 651 is provided with a memory (not shown) for storing calculation results.
[0022]
The automatic load calculation circuit 652 receives the arm position signal and outputs the result of calculating the target load applied to the sample in the spring control or a preset target load to the load control circuit 653 as a target load signal.
[0023]
The load control circuit 653 compares the A / D converted spring displacement signal with the target load signal (servo motor command data) output from the automatic load calculation circuit 652, and calculates a servo gain calculation circuit as a load control signal corresponding to the difference. The servo gain calculated in 651 is added and output to the D / A converter 657.
[0024]
The servo gain calculation circuit 654 receives the A / D-converted spring displacement signal and the arm position signal when the worker brings the indenter 3 and the sample s into contact and gives the initial test force, and performs spring control. The value for is calculated.
The target position calculation circuit 655 receives the spring displacement amount signal and outputs the result of calculating the target position of the load arm 4 in the spring control or a preset target position to the load arm position control circuit 656 as a target position signal.
The load arm position control circuit 656 receives the arm position signal from the arm position sensor, compares the arm position signal with the target position signal, adds a servo gain to the position control signal corresponding to the difference, and performs D / A conversion. To the device 657.
The D / A converter 657 performs D / A conversion on the load control signal and the position control signal and outputs them to the servo motor drive circuit 658.
The servo motor drive circuit 658 receives the D / A converted load control signal and position control signal, amplifies them with a current amplifier 658 a taking into account differential and integral elements, and then outputs them to the servo motor 61.
[0025]
The arm position sensor 8 is composed of, for example, a displacement sensor unit (linear scale) that optically reads a glass scale, and measures the amount of movement of the load arm 4 in the vertical direction, like the spring displacement sensor 64.
As shown in FIG. 3, the hardness calculator 9 includes an amplifier 91, an A / D converter 92, an arithmetic circuit 93, an output circuit 94, and the like.
[0026]
The amplifier 91 amplifies the arm position signal measured 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 arm position signal and outputs it to the arithmetic circuit 93.
The arithmetic circuit 93 calculates the hardness by calculating the A / D converted arm position signal in accordance with a built-in arithmetic program, and outputs the hardness to the output circuit 94. The output circuit 94 processes the calculated hardness data into data of a predetermined output format, and outputs the data to the output device 11 connected to the hardness tester 1. Here, the output device 11 is, for example, a display device that displays hardness data on a screen, or a printing device that prints and outputs hardness data on paper.
[0027]
Then, the load control signal or arm position control signal amplified by the servo motor drive circuit 658 is output to the servo motor 61, and the servo motor 61 is driven based on the load control signal or arm position control signal. Then, when the servo motor 61 is driven, the ball screw 62 rotates and operates upward. At that time, the leaf spring 7 attached to the ball screw 62 and the load arm 4 integrated therewith are pivoted upward, while the indenter 3 attached to the free end of the load arm 4 is raised by the operator. Contact with the prepared sample s.
At this time, the opening amount of the groove portion 7a between the leaf spring 7 and the load arm 4 is measured by the spring displacement amount sensor 64 as a spring displacement amount signal, and this spring displacement amount signal is amplified and is sent to the servo gain calculation circuit 651. Is output.
[0028]
Next, the autobrake control operation by the hardness tester will be described with reference to the flowchart shown in FIG.
First, when the autobrake process is started, the load arm 4 is initialized in step S1. That is, the neutral position is detected, and the load arm 4 rotates downward by a predetermined amount from the neutral position.
Next, in step S <b> 2, the spring displacement amount sensor 64 and the arm position sensor 8 are reset, and initial setting is performed so as to control the load arm 4.
Next, in step S3, when the sample s raised by the worker contacts the indenter 3, spring control is started.
Next, in step S4, reading values of the spring displacement sensor 64 and the arm position sensor 8 in the current state are input.
Next, in step S5, the load arm position control circuit 656 generates an error (Err) based on the equation (1),
Err = Gain × arm position (1)
The arm position control signal based on the error is D / A converted and then output to the servo motor 61 via the servo motor drive circuit 658.
[0029]
Next, in step S6, with the displacement of the load arm 4, a target load is set to the load based on the spring control.
Next, in step S7, it is determined whether or not the position detected by the arm position sensor 8 is a position below the horizontal by a predetermined amount (hereinafter referred to as an autobrake position), and is determined to be an autobrake position. If it is, the process proceeds to step S8, the autobrake is activated (on), the force control is switched to the force control at the time when the brake is applied (step S9), and then the process proceeds to step S10. On the other hand, if it is determined in step S5 that the position detected by the spring displacement sensor 64 is not the predetermined position, the process proceeds to step S10 as it is. Here, the predetermined position of the load arm 4 is a position where the test force falls within an appropriate accuracy range when the initial test force is applied to the load arm 4 from the position.
[0030]
In step S10, it is determined whether or not the force value detected by the spring displacement sensor 64 is a force for checking accuracy. Specifically, it is determined whether or not the force value is larger than a predetermined ratio of the initial test force. If it is determined that the force value is large, the process proceeds to step S11, but if it is determined that the force value is small, The process proceeds to step S12.
When the process proceeds to step S11, it is determined here whether or not the position of the load arm 4 is within a range in which the test force accuracy can be guaranteed. That is, it is determined whether or not the deviation of the load arm from the horizontal position is within a preset test force accuracy range. If the position of the load arm is not within the test force accuracy range, the process proceeds to step S13, where the servo motor 61 is stopped and the processing is stopped.
[0031]
On the other hand, when the position of the load arm 4 is within the preset test force accuracy range, after applying the force to the initial test force in step S14, the test force is applied in step S15, and after a predetermined time has elapsed, In step S16, the force is returned to the initial test force again, and after the hardness value is calculated in step S17, the hardness value is displayed.
Further, when the process proceeds to step S12 as a result of step S10, it is determined here whether or not the automatic brake is operating. If it is determined that the automatic brake is not operating, the process proceeds to step S4, and the processes after step S4 are performed again. On the other hand, if it is determined that the autobrake is operating, the process proceeds to step S18.
In step S18, it is determined whether or not it is within the brake holding time. If it is determined that it is not within the brake holding time, the process proceeds to step S4, and the processes after step S4 are performed again. On the other hand, if it is determined that it is within the brake holding time, the brake is turned off (step S19), the target load is set to the initial load (step S20), the process proceeds to step S4, and the process proceeds to step S4. Processing is performed again.
[0032]
Here, the operation of the load arm 4 in the spring control will be described with reference to FIG.
FIG. 6 is a diagram showing the relationship between the position of the load arm 4 and the load applied to the sample s in the spring control. In FIG. 6, the solid line indicates the load applied to the sample s, and the dotted line indicates the position of the load arm 4.
[0033]
In FIG. 6, first, the load arm 4 is maintained at a predetermined position (a position below the horizontal by a predetermined amount), and the sample s is not in contact with the indenter 3 (time t0). When the sample s is raised and contacts the indenter 3 (time t1), the load arm 4 rotates upward in a state where the indenter 3 is in contact with the sample s. At this time, as the load arm 4 is displaced from the predetermined position, the load applied from the indenter 3 to the sample s increases (time t1 → t2). If it is determined in step S7 that the position of the load arm 4 has reached the auto brake position, the auto brake is activated (time t2), and the load arm 4 operates to maintain the load at this time. . Then, after step S9, step S11, and step S14, the load arm 4 is rotated again (time t3), and the initial test force is applied to the sample s in the horizontal position (time t4).
[0034]
When the above-described spring control is performed, the impact at the time of contact between the indenter 3 and the sample s is reduced compared to the conventional method in which the load arm 4 is fixed, and the initial test force is exceeded at the time of contact. This is particularly effective in the case of a hardness test in which a small test force is applied to a sample, such as a superficial type hardness tester. FIG. 7 is a diagram showing a load applied to the sample when the indenter and the sample are in contact with each other. FIG. 7A shows the case of the conventional hardness tester, and FIG. 7B shows the case of the hardness tester 1. FIG. In FIG. 7A, at the moment (time t1) when the indenter contacts the sample, the sample is impacted and reaches the vicinity of the initial test force. On the other hand, in FIG. 7B, at the moment (time t1) when the indenter 3 and the sample s contact each other, no impact is applied to the sample s, and a load is gradually applied to the sample s.
[0035]
Next, the test load control operation by the hardness tester will be described with reference to the flowchart shown in FIG.
First, when the power is turned on, each variable is initialized in step S21. Specifically, values such as servo gain (Gain), error (Err), arm position (DIFP), and load (DIFF) are initialized. A target load is input to a load input unit (not shown).
Next, in step S22, the values of the spring displacement amount (load) sensor 64 and the arm position sensor 8 in the current state are input to the servo gain calculation circuit 651, and these values are stored in a memory (not shown) built in the servo gain calculation circuit 651. (Step S23). This is for use in load control in the next routine.
[0036]
Next, in step S24, a preset preliminary test load is applied to the sample to determine the initial servo gain. When the arm position at that time is input to the servo gain calculation circuit 651, the initial servo gain is determined by the equation (2).
Gain = A x (DIFF-load value) / (DIFP-arm position) (2)
Here, A is an arbitrary constant.
Next, in step S25, an error, that is, the difference between the actual load value and the target load value is calculated by equation (3).
Err = Gain × Load value-TargetF (3)
In step S26, it is determined whether an error remains. That is, it is determined whether or not the difference between the comparison error (Err1) obtained in the previous feedback routine and the current error (Err) is “0”. If “0”, the process proceeds to step S27. If it is not “0”, the process proceeds to step S28.
Here, when determining whether or not an error remains, it is determined that an error remains when the error difference continuously becomes “0” in a predetermined number of times (for example, five times) of the feedback routine. May be. The servo gain may be increased step by step.
[0037]
In step S27, a process for increasing the servo gain by a predetermined value is performed, and then the process proceeds to step S28.
Next, in step S28, it is determined whether or not the servo gain exceeds the allowable upper limit value. If the servo gain exceeds the allowable upper limit value, the process proceeds to step S29 to perform a process of lowering the servo gain by a predetermined value. The process proceeds to step S30. On the other hand, if the allowable upper limit is not exceeded, the process proceeds to step S30 as it is.
[0038]
Next, in step S30, it is determined whether or not the test force is being held. If it is determined that the test force is being held, the process proceeds to step S31, but if it is determined that the test force is not being held. Shifts to Step S32.
When the process proceeds to step S32, it is determined whether or not the target test force is reached. When the target test force is not reached, the process returns to step S22 and the process is repeated again. In the case of power, after starting the timer in step S33, the process returns to step S22 to continue the process of step S22.
On the other hand, as a result of the determination in step S30, when the process proceeds to step S31, it is determined whether or not the timer has reached the holding time. If the holding time has not been reached, the process returns to step S22 to continue the process. When the holding time is reached, the test load loading and holding ends.
[0039]
After the end of the test load control operation, the indentation depth is measured by the arm position sensor 8 as an arm position signal. The arm position signal is amplified by an amplifier 91 and is converted into an A / D converter 92 by an A / D converter 92. It is converted and output to the arithmetic circuit 93.
Next, the A / D converted arm position signal is calculated by the calculation circuit 93 according to a built-in calculation program to calculate the hardness. The calculated hardness data is output from the predetermined output device 11 via the output circuit 94.
[0040]
According to the indentation forming mechanism 10 and the hardness tester 1 according to the present invention described above, when the indenter 3 and the sample s are brought into contact, the spring control of the load arm 4 is performed from the moment of contact. That is, after the sample s is brought into contact with the indenter 3, the rotation of the load arm 4 is controlled so that a load is gradually applied from the indenter 3 to the sample s according to the displacement from the reference position.
[0041]
Therefore, when the sample s is brought into contact with the indenter 3, a load can be gradually applied without giving an impact to the sample s, and the problem of applying a load exceeding the initial test force at the moment of contact is solved. Is done.
[0042]
Further, since the operation related to the spring control of the load arm 4 is controlled by the servo motor 61 or the like, the operation of various spring constants can be simulated, and the sample s can be compared with a case where an elastic body such as a spring is actually used. An appropriate spring constant according to various conditions such as hardness can be easily realized.
[0043]
Furthermore, since the worker can raise the sample stage 5 and perform the operation of the handle etc. when bringing the indenter 3 and the sample s into contact with each other with the same feeling as before, a more appropriate work result can be obtained. A substantial improvement in operability can be realized.
[0044]
In the above embodiment, the timing for starting the spring control is the moment when the indenter 3 and the sample s are in contact with each other. However, distance detection means (a distance sensor or the like) for detecting the distance between the indenter 3 and the sample s is provided The load arm 4 may be rotated at an appropriate speed when the indenter 3 and the sample s approach each other by a predetermined distance. In this case, the impact generated at the moment when the indenter 3 and the sample s come into contact with each other can be further reduced.
[0045]
【The invention's effect】
According to the first aspect of the present invention, since the impact relaxation means is provided, the impulse that the indenter gives to the sample at the time of contact between the sample and the indenter can be reduced. That is, since the impact when the indenter contacts the sample is reduced, the problem of exceeding the initial test force at the time of contact can be solved.
[0046]
According to the second aspect of the invention, since the load control means and the moving means are provided, a load corresponding to the displacement from the reference position of the indenter is given to the sample, and an operator who manually moves the sample is conventionally In the same manner as described above, a predetermined load can be applied to the sample more appropriately by simply operating the handle or the like.
[0047]
According to the invention of claim 3, since the distance detecting means is provided, one can be moved in the same direction as the other immediately before the sample and the indenter contact each other, and the moment of contact between the sample and the indenter In addition, the impact can be further reduced.
[0048]
According to the invention described in claim 4, since the indentation forming mechanism according to any one of claims 1 to 3 is provided, when the sample and the indenter are contacted, the initial test force is not easily exceeded. This improves work efficiency. Moreover, since the initial test force is not exceeded at the time of contact, the reliability with respect to the result of the hardness test is improved.
[Brief description of the drawings]
FIG. 1 is a side view showing a configuration of a main part of a hardness tester according to the present invention.
FIG. 2 is a block diagram showing a main configuration of a load arm movement control unit according to the present invention.
FIG. 3 is a block diagram showing a main configuration of a hardness calculation mechanism according to the present invention.
FIG. 4 is a flowchart showing an autobrake control operation.
FIG. 5 is a flowchart showing a test load control operation.
FIG. 6 is a diagram illustrating the operation of the load arm 4 in spring control.
7 is a diagram showing a load applied to a sample when the indenter and the sample are in contact with each other. FIG. 7A shows a case of a conventional hardness tester, and FIG. 7B shows a case of a hardness tester 1. FIG.
FIG. 8 is a side view showing a main configuration of a conventional hardness tester.
[Explanation of symbols]
1 Hardness tester
2 Body
3 Indenter
4 Load arm
5 Sample stage
6 Load arm working part
7 leaf spring
8 Arm position sensor
9 Hardness calculation part
10 Indentation formation mechanism
11 Hardness calculation mechanism
61 Servo motor
62 Ball screw
64 Spring displacement sensor
65 Load arm operation controller
s sample

Claims (4)

An indentation forming mechanism used in a testing machine for measuring material properties of a sample based on forming an indentation on a sample surface with an indenter,
When the sample and the indenter are brought into contact with each other, provided with an impact relaxation means for controlling movement of one of the indenter and the sample in the same direction as the other,
An indentation formation mechanism that reduces an impact generated between the sample and the indenter by reducing an impulse upon contact. The impact relaxation means is
A load control means for calculating a predetermined load applied to the sample in accordance with a displacement from a reference position of the indenter when the sample is in contact with the indenter;
Moving means for moving the indenter in the same direction as the sample so as to give the sample a predetermined load calculated by the load control means;
The indentation formation mechanism according to claim 1, comprising: The impact relaxation means is
A distance detecting means for detecting a distance between the indenter and the sample;
2. When the indenter and the sample approach each other by a predetermined distance, one of the indenter and the sample is controlled to move at a predetermined speed in the same direction as the other to reduce the impulse at the time of contact. 2. Indentation formation mechanism according to 2. A hardness tester comprising the indentation forming mechanism according to claim 1.

Images