JPH0886728A - Tester for evaluating strength reliability - Google Patents

Abstract

PURPOSE: To enable evaluating the strength reliability of a material or small parts using a simple and small device by subjecting a test piece to high-speed, repeated deformation at a fixed amplitude. CONSTITUTION: A miniature test piece in the form of a thin plate about 0.3 to 3.0-mm thick or a round bar about 0.3 to 3.0 ϕ in diameter is mounted between a deforming jig 2 directly coupled to a stepping motor shaft 4 and a test piece clamp 3, and is tested for bending fatigue as it is repeatedly bent by the turning of a stepping motor 1 which provides small output torque, is small, easy to control and has high positioning accuracy. When the sum of the distance I1 from the center of the shaft 4 to the inner end face of the jig 2 and the distance I2 from the center of the shaft 4 to the inner end face of the clamp 3 is about 15 to 30mm, for example, the distribution of bending moments can be controlled to an accuracy of several % errors through fine adjustment of the position (distance I2 ) of the clamp 3 to an accuracy of 0.2 to 0.3mm using a pushing bolt 10 and a microhead 11 having an accuracy of 1/100mm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a test technique for evaluating the strength reliability of a material or a small component by applying a cyclic deformation of a relatively small miniature test piece at a high speed and a constant amplitude, and to various metals. The present invention relates to a strength reliability evaluation test device used for basic research on strength characteristics of non-metallic materials, quality inspection at the time of purchase of product materials, manufacturing process of small parts and completion.

[0002]

2. Description of the Related Art Conventionally, since the size of a mechanical element that requires guarantee of strength reliability is relatively large, a fatigue testing machine or other testing apparatus for strength reliability evaluation has a plate thickness of 3 to 3.
The target was a 30 mm plate-shaped test piece and a round bar test piece having a diameter of about 3 to 30 mm. Therefore, a large driving force was required to give these test pieces cyclic deformation at high speed. For this reason, in the conventional test equipment, as a method of repeatedly applying a load to the test piece, a method of utilizing reciprocating motion of the piston by hydraulic pressure or a one-way rotational motion of the motor by a mechanical method (cam, link mechanism, etc.) is used. The method of converting into a reciprocating motion is adopted by the above, and the test piece as described above has been tested with sufficient accuracy (PW type or PWO manufactured by Tokyo Hoki Co., Ltd.).
Shape plane bending-torsion fatigue tester). However, with the development of the semiconductor and electronics fields, the number of small precision equipment has also increased, and the necessity of strength reliability assurance tests for the small parts that compose these and life tests of small materials corresponding thereto has increased. However, in a testing device in which a conventional type testing machine is simply downsized, the inertial force of the reciprocating portion is larger than the load applied to the test piece, and the mechanism is complicated, which makes practical application difficult. In addition, a small-sized test device that can be practically used is not commercially available.

[0003]

DISCLOSURE OF THE INVENTION The present invention, which is a departure from the above-mentioned prior art, has a simple mechanism, a relatively small inertial force due to reciprocating motion, and a plate shape with a plate thickness of 0.3 to 3.0 mm. We propose a tester that can perform strength reliability evaluation by applying repeated deformation at high speed to a test piece and a miniature size test piece such as a round bar test piece with a diameter of 0.3 to 3.0 mm. To aim.

[0004]

In order to achieve the above object, the present invention proposes the following strength reliability test apparatus.

A thin plate or a plate having a plate pressure of about 0.3 to 3.0 mm, which has a test apparatus main body, a test piece fixing tool supported by the main body, and a deformation adding jig for deforming the test piece. In a strength reliability evaluation test device that evaluates the strength reliability of a material by repeatedly applying deformation to a small diameter rod or coil of about 0.3 to 3.0φ, in order to apply repeated deformation to a test piece at a constant amplitude. A strength reliability evaluation test device comprising: a motor as a drive source; and a deformation adding jig that is directly connected to the shaft of the motor and directly transmits the repeated constant amplitude deformation to a test piece.

In this strength reliability evaluation test apparatus, the motor is any one of a step motor, an ultrasonic motor, a DC servo motor, and an AC servo motor.

A thin plate or a plate having a thickness of about 0.3 to 3.0 mm, which has a test apparatus main body, a test piece fixing tool supported by the main body, and a deformation adding jig for deforming the test piece. In a strength reliability evaluation tester for evaluating strength reliability of a material by repeatedly applying deformation to a small diameter rod or coil having a diameter of about 0.3 to 3.0, the material is supported by the main body and positioned by a micro head. The test piece fixture, the step motor as a drive source for applying repeated deformation to the test piece at a constant amplitude, and the deformation adding jig directly connected to the shaft of the motor, are deformed from the center of the motor shaft. When the distance l ₁ to the inner end face of the additional jig and the distance l ₂ from the center of the motor shaft to the inner end face of the test piece fixture are set, l ₁ and l ₂ are variable. Strength trust Evaluation test equipment.

A test apparatus main body, a test piece fixture supported by the main body, and a deformation adding jig for deforming the test piece, and a thin plate having a plate thickness of about 0.3 to 3.0 mm or a diameter. In a strength reliability evaluation test device that evaluates the strength reliability of a material by repeatedly applying deformation to a small diameter rod or coil of about 0.3 to 3.0φ, in order to apply repeated deformation to a test piece at a constant amplitude. A step motor as a drive source, the deformation adding jig directly connected to the shaft of the motor, and a non-contact displacement meter for measuring the displacement of a test piece are provided, and a set value is set with reference to the output of the displacement meter. The control function that increases the displacement amplitude up to, and repeatedly applies deformation while keeping this amplitude constant (as described above,
A strength reliability evaluation test device, which is characterized by having a "feedback control function".

In this strength reliability evaluation test device, the sampling / feedback control function has the following structure: (1) Target displacement setting input value (± input pulse number) )
Drive the step motor for one cycle to several cycles of repeated displacement, measure the target displacement amplitude with a non-contact displacement meter, and store the result. (2) Set the step motor from the displacement setting input value. Driven with a low input value, increase the number of input pulses while comparing the previously stored target displacement amplitude and measured displacement amplitude with each cycle, and set the difference between the stored target displacement amplitude and measured displacement amplitude to a predetermined value ( For example, 1 / displacement equivalent to one pulse input
Continue driving until 2), (3) Obtain the number of input pulses that satisfy the condition of (2), and drive the step motor for a certain time or a certain number of cycles with the number of pulses, (4) For a predetermined time or for a predetermined period Perform sampling feedback control again after the number of cycles has elapsed.

A non-contact displacement gauge for measuring the displacement of the test piece is provided, and the step motor is installed horizontally and its rotation axis is in the front-back direction with respect to the experimenter side.
Further, the test piece fixture is attached to the base plate of the test apparatus main body through a slide mechanism so that the test piece can be finely adjusted in the longitudinal direction, and is further sandwiched by a push bolt and a micro head of 1/100 mm accuracy. It may be fixed and installed. Further, the test piece fixture may be arranged in the longitudinal direction of the axis of the step motor and aligned with the axis, and may be installed on the base plate of the test apparatus main body via a roller.

A microscope or a magnifying observation sensor may be provided above the test piece, and this may be installed on a table that can be finely moved in the X, Y, and Z triaxial directions.

In particular, the invention proposes to use a stepper motor as a drive source for applying repetitive deformations at constant amplitude to the test piece at high speed.

Repetitive deformation of the test piece at high speed will be described.

In the fatigue test, the total number of repetitions was 10 ₆ to 1
In the case of 0 ₇ times, it is important from the viewpoint of shortening the time to test at a repetition rate as high as possible within the range where there is no problem in the nature of the test. In addition, there are limits due to the restrictions of the testing machine. Testing at frequencies above 10 HZ can usually be considered high speed. On the other hand, it exceeds the 10HZ from dynamic characteristics of Fig. 8 _△
“High speed” because θ _d / _△ θ _s has begun to exceed 1.0.
It seems reasonable to define the definition of 10HZ or more.
However, as can be seen from Figure 8, shows a resonance at 2～3HZ, since _{△ θ d} / _{△ θ s} is set to about 1.1, may fall fast ranging with a more 1HZ . In short, "high speed" is a relative speed, and refers to a speed range in which resonance phenomenon occurs or overshoot due to inertial force increases. In the case of the embodiment of the present invention, "high speed" is assumed to be 2HZ or more from FIG.

The step motor will be briefly described below. In "Electrical Engineering Handbook" (pages 576 to 578), the step motor is also called a stepping motor or stepper, and is characterized by being driven by an electronic circuit. Therefore, it has been shown that the basic operating system consists of a pulse distributor and a drive circuit. It has been widely used for positioning control, and it has been shown that when the pulse frequency is increased, the step motor rotates smoothly, so it is also used for constant speed operation.

The step motor includes VR type, PM type,
There are hybrid type, claw pole type, disk rotor type, and the like, and it is shown that there are unipolar drive, bipolar drive, bifilar winding drive, and other drive methods as the drive method.

In consideration of the overshoot of the step motor, a non-contact displacement gauge is provided to measure and control the displacement so as not to cause an excessive deformation than the set value. To prevent excessive deformation,
Start from an input that is sufficiently lower than the target set input value, read the displacement meter's output, and gradually increase the input until the displacement amplitude reaches the set value without giving excessive deformation to the test piece. The strength reliability evaluation test apparatus may be characterized by having a control function of increasing the amplitude and keeping the amplitude constant and performing a repeated deformation strength test, that is, a sampling / feedback control function.

In the case of repetitive deformation at a low speed without overshoot development, this sampling / feedback control is unnecessary, and the displacement during the test is measured and recorded by the non-contact displacement meter even at a high speed. If this is used to process the data, this sampling / feedback control is unnecessary.

As described above, the same result as that of the step motor can be obtained even with a motor having a high positioning accuracy such as an ultrasonic motor, a DC servo motor, an AC servo motor.

Regarding the ultrasonic motor, the above-mentioned "Electrical Engineering Handbook" converts a force of strong ultrasonic vibration into a unidirectional motion of straight or rotation, and is shown to be a new type of motor. (Page 582). It has been shown that the ultrasonic motor has a simple structure, is small and lightweight, and has good responsiveness and excellent controllability.

Regarding the principle of the servo drive device, the servo drive device is a part of a servo mechanism used for feedback control of a mechanical device, and is composed of a control unit (drive amplifier), a controlled object (motor) and a detection unit. ing. The controlled variable has been shown to be the speed and position of the servomotor or the machine coupled to it (pages 1686-1690).

Unlike ordinary motors, DC servo motors and AC servo motors have counters and circuits for measuring deviations from target values (target values) such as the number of revolutions and position, and provide accurate speed control and position control. This motor system can be used to drive the pen or chart of the measurement recording device, the robot arm, etc. by taking advantage of its characteristics. Further, the ultrasonic motor converts the high frequency vibration of the vibrator using the elastic deformation energy of the piezoelectric element into a motion according to the number of high frequency pulses via frictional force. This is also excellent in position control characteristics.

Therefore, by utilizing the position control function of these motors, the (± input value) of the motors can be switched and input at high speed by the personal computer to perform control.

In the strength reliability evaluation tester, the thin plate test piece is supported by two thin plates so as to release the axial force component during repeated bending deformation, and to release the bending deformation of the rod during repeated torsional deformation of the small diameter rod. The test piece fixture is characterized by having a loop type load measuring part on one or both of the above two thin plates, and by attaching a strain sensor such as an electric resistance strain gauge to it Measures the change in bending moment or torsion moment applied to the test piece over time,
It is possible to use test strip fixtures that allow recording.

Further, particularly in the repeated bending test of the thin plate, the bending moment distribution of the test piece is made uniform in the longitudinal direction of the test piece, or the bending moment on the side of the test piece fixture is increased to increase the deformation addition jig side. Relative position between the test piece and the center of the step motor shaft in order to freely select whether to reduce the bending moment on the fixture side to increase the deformation addition jig side. 1
A test piece equipped with a slide device for finely moving the jig for fixing the test piece in the longitudinal direction of the test piece and a micro head for setting this with an accuracy of 1/100 mm so that adjustment / setting can be easily performed on the order of / 100 mm. Fixtures can be used.

The method of fixing the test piece to the test piece fixture and the jig for adding deformation is usually using bolts, but since the test piece of this tester is a thin plate, a strong magnet holding plate is used. It is possible to fix the test piece.

In the strength reliability evaluation test apparatus, in order to prevent excessive deformation due to the overshoot phenomenon of the step motor from being applied to the target displacement setting input value at the initial stage of startup, (1) Displacement setting input value (± number of input pulses)
On the other hand, at the same time as the start-up, the displacement is repeated for one cycle to several cycles, and the step motor is driven by (± input pulse number) at a slow pulse rate that does not cause overshoot, and the target displacement amplitude is measured by the non-contact displacement meter. Measure and record by.

(2) Next, the reciprocating drive is started at the designated pulse rate, but at the beginning, the input value is sufficiently lower than the set (± input pulse number), and stored before.
While comparing the target displacement amplitude and the measured displacement amplitude every cycle, (± input pulse number) is increased by one pulse, and the difference between the stored target displacement amplitude and the measured displacement amplitude is a predetermined value (for example, one pulse input equivalent). Until it becomes 1/2) of the displacement of. Although the number of input pulses on the plus side and the number on the minus side have been described as the same value in the above, it is of course possible to change the number of pulses on the plus side and the minus side. further,
Even after the above conditions are satisfied on both the positive side and the negative side, such feedback sampling control operation can be continued until the end of the test. Especially when the rigidity of the test piece changes with time, such an operation is necessary to maintain a constant amplitude. However, when the rigidity of the test piece does not change so much, the following control (3) is advantageous. One of the features is that you can make such choices freely.

(3) When the condition (± input pulse number) satisfying the condition (2) above is obtained, the sampling / feedback control is interrupted at that time and fixed at (± input pulse number) at that time. Drive for a time (or a fixed number of cycles). After a lapse of a predetermined time, the sampling / feedback control is performed again, and if the deviation from the condition (2) above is corrected, the corrected (± input pulse number) is driven again for a fixed time (or a fixed number of cycles). To do.

(4) The intermittent sampling / feedback control as described above is executed until the test piece is broken or the total number of repetitions reaches a predetermined value.

(5) The control described above can be controlled by an ordinary personal computer. In addition, since there is a margin in the function of the personal computer during the period of operation when sampling / feedback control is interrupted, the displacement amplitude for each cycle is measured, and the displacement waveform for a specific one cycle is measured and stored. Causes the printer to perform processing such as output.

We propose a strength reliability evaluation test device characterized by the following equipment arrangements.

(1) The step motor, which is the drive source, is installed horizontally and the rotation axis is in the front-back direction with respect to the experimenter, and the deformation addition jig is on the front side of the motor (close to the experimenter). Side) rotor tip.

(2) In the case of repeated bending, the test piece should be mounted horizontally between the motor and the experimenter and at a position such that the longitudinal direction of the test piece should be aligned with the right and left direction of the experimenter ( Install the specimen fixture (in the middle between the motor and the experimenter).

The test piece fixture is attached to the base plate through a slide mechanism that allows fine adjustment of the installation location in the longitudinal direction of the test piece.
The mm-precision micro head is installed so that it can be pinched and fixed in position. Further, a non-contact displacement gauge for measuring the bending displacement of the test piece is installed vertically below the deformation adding jig so that the swing width of the deformation adding jig can be measured as the vertical displacement. . In addition, this non-contact displacement gauge is attached to a fixture via a micro head with a precision of 1/100 mm so that it can be verified and the vertical position can be set without removing the displacement gauge. It is attached to the base plate via a slide mechanism that can adjust the position in the left-right direction (longitudinal direction of the test piece) according to the size of the tool.

(3) A microscope or a magnifying observation sensor is fixed on the motor and the test piece so that the damage on the surface of the test piece during the test can be observed and monitored.
A table that can be finely moved in the X-, Y-, and Z-axis directions is installed.

This table is at the rear (the side far from the experimenter)
Is supported by 2 pins and the front part is supported by 2 legs,
The surface of the test piece can be observed at any time during the test, but when the test piece is attached or detached, the test piece can be attached or detached without moving and removing the table by rotating the pin at the rear part upward and lifting and supporting it.

(4) Various characteristic tests having other characteristics can be performed by partially changing the arrangement of the equipment described above. An example is shown below.

I) A chuck similar to the round bar twisting chuck of a normal fatigue tester is attached to the tip of the motor shaft instead of the deformation adding jig described above, and the test piece fixture is the case of the above (2). It is possible to perform a torsional fatigue test of a round bar by rotating the position by 90 ° and setting the position on the axis extension line before the motor shaft. Furthermore, this test piece fixture is not completely fixed to the base plate, but is installed on the base plate via a roller so as to be unconstrained in the test piece longitudinal direction (coincident with the motor axis direction), and the test piece fixture It is possible to perform ratcheting test by constant load axial force and repeated torsion on the test piece by pulling the coil spring with a coil spring.

II) In the thin plate bending test apparatus described in (1) and (2) above, the initial position of the deformation adding jig is not set on the same horizontal plane as the test piece fixture, but 45 ° from the horizontal plane.
By installing it at any position such as °, 90 °, 140 °, and swinging with this position as a reference, it is possible to carry out a repeated bending test of a bent plate having a bent portion.

[0041]

As an example, a step motor having a small output torque but simple control and high position control accuracy is used as a drive source. Since the target test piece is a miniature size, the torque required for driving is quite small, and it can be driven sufficiently with the output torque of the step motor.

Therefore, positive and negative pulse inputs are alternately input to the step motor to vibrate the pulse motor shaft at positive and negative speeds at high speed, and the test piece is repeatedly bent or deformed through a deformation addition jig directly connected to the shaft end. Repeated torsional deformation can be generated. Unlike the conventional method, the motor
The feature is that the mechanism is extremely simple because it directly vibrates positively and negatively at high speed. That is, one end of a thin plate test piece or a round bar test piece is fixed to a test piece fixing base, the other end is fixed to a deformation adding jig, and the deformation adding jig is vibrated at high speed by a step motor. The test piece can be repeatedly deformed.

However, when the step motor is driven at a high speed, a so-called overshoot phenomenon occurs due to the inertial force of the rotor at the time of stopping or reversing, and the shake of the rotor and the deformation addition jig is predicted from (± input pulse number). It is larger than the theoretical swing. That is, when the step motor is driven at a slow pulse rate that does not cause an overshoot phenomenon, the theoretical swing width predicted from (± input pulse number) is equal to the actual swing width, but the pulse rate is increased (excitation As the frequency of use increases), the actual swing width increases due to overshoot. Moreover,
The amount of this overshoot increases as the pulse rate increases, and the swing width increases in a complicated manner while showing peak values at a plurality of resonance points. However, even if it is driven for a long time at an arbitrary pulse rate, its overshoot amount is stable at a constant value, so during the test, the runout width was measured and recorded by a non-contact displacement meter, and this was used to record the data. Can be processed.

In consideration of convenience in use (± input pulse number), it is desirable to always drive with a theoretical fluctuation width predicted from the pulse number regardless of the pulse rate. On the other hand, in the strength reliability evaluation test, driving is performed at a constant amplitude for a long time, but suddenly a predetermined (± pulse number) is input at a predetermined pulse rate to drive the target theoretical amplitude due to overshoot at startup. Than the above, the method of lowering (the number of input pulses) gradually becomes the theoretical amplitude while driving this,
The effect of repeated excessive deformation at startup remains. Therefore, by performing sampling / feedback control at the time of starting, it is possible to prevent excessive displacement from being applied at the time of starting and to perform a strength reliability test with a predetermined theoretical amplitude.

[0045]

The details of the present invention will be described in the following examples.

FIG. 1 is a plan view showing an embodiment of a step motor 1, a deformation adding jig 2, and a test piece fixture 3 according to claim 1, and FIG. 2 is a side view of the same. The deformation adding jig 2 is directly connected to the shaft 4 of the step motor.
As can be seen, a thin plate test piece is mounted between the test piece fixture 3 installed on the left side of the test piece and the step motor is oscillated to repeatedly bend and deform the test piece to perform a bending fatigue test of the test piece. . 1 and 2 show a step motor 1, a test piece fixture 3, a deformation adding jig 2
It is also the figure which showed the Example of arrangement | positioning. FIG. 3 is a front view of FIG. 1, and is an explanatory view of an embodiment of the test piece fixture. The test piece fixture 3 is a thin plate 6 for supporting two test piece fixtures.
It is considered that the axial force component generated in the test piece due to the bending deformation of this thin plate is released and a pure bending stress is generated in the test piece. The test piece is fixed by the test piece pressing plate 5. The test piece pressing plate 5 is designed to hold the test piece with bolts in this embodiment. However, when many test pieces are to be automatically tested, the pressing plate 5 is made of a strong magnet to attract the magnet. It is also possible to have a structure in which the test piece is pressed by force. Further, the test piece fixture supporting thin plate 6 is provided with a loop type load measuring section as shown in FIG. That is, a sensor such as a strain gauge is attached to the surface of the loop portion and the elastic strain of the loop portion is measured to obtain the axial load applied to the thin plate 6 for supporting the test piece fixture, and the axial load is applied to the test piece from this value. The value of the bending moment and its change over time can be measured and recorded. Further, depending on the magnitude of the axial load applied to the supporting thin plate 6, this loop portion is
It may be provided over the entire width of the thin plate 6 as shown in (b), or the measurement sensitivity can be improved by providing a loop in a part of the width and hollowing out the other as shown in FIG. 4 (C). The shape of the loop depends on the size of the load,
The shape as shown in FIG. 4A or the shape as shown in FIG.

Next, an embodiment will be described with reference to FIGS. 1, 2 and 3. In order to control the distribution shape of the bending moment applied to the test piece, the dimensional relationship between the dimensions l ₁ and l ₂ shown in FIG. 1 is important. Here, l ₁ is the distance from the center of the motor shaft to the inner end surface of the deformation adding jig 2, and l ₂ is the distance from the center of the motor shaft to the inner end surface of the test piece fixture 3. As a result of the analysis, the following was found. That is, l ₁ =
In the case of l ₂ , a uniform bending moment is generated in the test piece in the longitudinal direction, but in the case of l ₁ > l ₂ , the bending moment of the test piece fixture side is large and the bending of the deformation addition jig side is large. The moment is small, and the distribution is linear between them. Also l
On the contrary, when ₁ <l ₂ , the bending moment on the test piece fixture side is small and the bending moment on the deformation addition jig side is large. Further, in order to control the distribution of the bending moment to an accuracy of a few percent, when the length of (l ₁ + l ₂ ) is about 15 to 30 mm, the length l ₂ is 0.2 to 0.
It turns out that it is necessary to adjust with an accuracy of 3 mm. Therefore, in this embodiment, the test piece fixture mounting base 9 is fitted into the slide rail 8 and further the push bolts 10 and 1 /
The micro head 11 is pinched and fixed between the micro head 11 and the micro head 11 having an accuracy of 100 mm, and the position of the micro head 11 can be finely adjusted.

In FIGS. 5 and 6, the thick line in the drawings illustrates an example of the mounting state of the non-contact displacement gauge. Non-contact displacement gauge 12
As can be seen from FIG. 5, the sensor part of 1 is installed directly below the deformation adding jig 2. The non-contact displacement gauge 12 is fixed to a non-contact displacement gauge mounting base 15 via a non-contact displacement gauge supporting plate 13 and a micro head 14, and the non-contact displacement gauge mounting base 15 is further provided with an elliptical hole to test apparatus main body 100.
It is bolted to the base plate 16 of. Therefore, the non-contact displacement meter 12 simultaneously performs on-site sensitivity verification and vertical position adjustment by the micro head 14, and is compatible with a plurality of deformation addition jigs having different l ₁ sizes according to the length of the test piece. As possible, the position can be adjusted by the elliptical hole of the non-contact displacement gauge mounting base 15. FIG. 6A is a plan view of the displacement gauge mounting state, and FIG. 6B is a side view of the displacement gauge mounting base 15.

FIG. 7 is a diagram for explaining the overshoot phenomenon of the step motor. When a step input is applied to the step motor at high speed (at a large pulse rate), the behavior becomes as shown in Fig. 7 (a), and due to the inertial force of the rotor and the like, the overshoot is largely over the angle corresponding to the input pulse number After that, it slightly oscillates and hangs at an angle corresponding to the input pulse. However, if the rotor is slowly raised with a small pulse rate, the inertial force of the rotor will decrease and
No overshoot occurs as in (b). Therefore, when (± input pulse number) is alternately input to the step motor to oscillate, and when the pulse rate is made small (rise slowly), the waveform becomes as shown in FIG. Since it does not occur, the rotation angle of the rotor oscillates at an angle corresponding to the number of input pulses. But,
When the pulse rate is increased (raised at a high speed), the actual amplitude becomes larger than the amplitude corresponding to the number of input pulses because overshoot occurs at the upper end and the lower end as shown in FIG. 7D. The actual amplitude theta _d, and the amplitude of the theta _s corresponding to the number of input pulses, indicating an example of the relationship between θ _d / θ _s and the pulse rate is shown in Figure 8. In FIG. 8, the horizontal axis is converted into the vibration frequency and is entered. From the figure, θ _d is considerably larger than θ _s and is inconvenient to use, so sampling feedback control was performed. An example thereof will be described with reference to FIG. FIG. 9A is an explanatory diagram for setting a target waveform required to swing the step motor,
Pulse rate (PP) that regulates motor drive speed
S), the number of pulses defining the swing amplitude on the + side (here A), the number of pulses defining the swing amplitude on the-side (here B), and the waiting time T ₀ at the upper and lower ends. The waveform is unique. When starting up the step motor, if these numerical values are input and started, this control program controls the movement of the step motor according to the following procedure.

(1) The step motor is set to (+) with a slow (without overshoot) pulse rate.
Driving from (A) pulse to (-B) pulse several times, as shown in FIG.
As shown in (b), the values of the non-contact displacement meter at the time of A, (A-1), and (A + 1) pulses are read, and from these numerical values, the non-corresponding position corresponding to the (A ± 1/2) pulse is determined. The value of the contact displacement meter is calculated and calculated as an average value of several times (about once to about three times). This is stored as (DA +) and (DA-).

The same processing is performed on the (-B) pulse side. Due to the nature of the strength reliability test, if you do not want to add more than the set value to the test piece, read only the values of the (А-1) pulse and the A pulse, and do not drive until the (A + 1) pulse. , (A-1) to (DA +), (DA-)
It may be a method of calculating.

Next, the driving is started at the pulse rate input previously, but the number of input pulses starts from ± 1 pulse, and n cycles of the actual measured value of the (+) side maximum value including overshoot are included. Average value (DA ') and (DA +)
And (DA-), and (DA ') <(DA-)
If so, increase by 1 pulse and make ± 2 pulses in the same way,
This process is repeated until (DA ') falls between (DA-) and (DA +). Note that the number of n cycles for obtaining the average value can be set in advance. If in the middle (DA ')> (DA
If it becomes +), reduce 1 pulse on the contrary, and (DA ')
If is between (DA-) and (DA +), the number of input pulses is left unchanged. The same process is performed on the (-B) pulse side. The above-described processing will be referred to as sampling feedback processing below. (DA ') is (DA
Between (-) and (DA +), (DB ') becomes (DB
Sampling feedback processing is performed until it falls between −) and (DB +), but if the above conditions are satisfied, sampling feedback processing is interrupted, and the number of input pulses at that time is fixed, and a preset number of repetitions (or Drive for a certain period of time. After driving for a predetermined number of repetitions (or for a predetermined time), sampling feedback processing is performed again to correct the deviation from the initial setting value, and then the corrected input pulse number is fixed and the predetermined number of repetitions (or predetermined Time) to drive.

The drive including the intermittent sampling feedback process as described above is driven until the test piece is broken or the total number of repetitions reaches a predetermined value.

During the period in which the sampling feedback process is interrupted and the fixed number of input pulses is in operation, the function of the personal computer used for the control process has a margin, so the following data process should be performed. Can be done.

(A) The maximum and minimum displacements of each cycle during operation are measured and stored in a memory.

(B) The data in the memory is output to the printer as a chart.

(C) The displacement during one cycle is measured and stored in detail at a constant number of repetitions, or at a constant time, or by a signal from an experimenter, and this is output as a displacement waveform.

10 and 11 show examples of a microscope mounting table for online monitoring of the condition of the surface of the test piece during the test, and a side view is shown in FIG. 10 and a plan view is shown in FIG. . The optical microscope 19 is in the Z-axis direction (vertical direction)
It is installed on the base plate 16 with four legs via a minute movement mechanism 18 and an X and Y direction minute movement mechanism 17.

The rear two legs (the side farther from the microscope) are supported by the rear leg support pins 20, and the front two legs 2 are supported.
1 is directly installed on the base plate 16. During the experiment, it is possible to observe and monitor the situation at any place on the surface of the test piece by means of the minute moving mechanisms 17 and 18. In addition, when the test piece is attached or detached, the space around the test piece can be secured by rotating the microscope upward together with the table around the pin of the rear leg and lifting it and supporting it with a stopper.

Further, another embodiment of the present invention will be shown. FIG.
2 is an explanatory view of a repeated bending test of a bent thin plate having various angles such as U-shape and L-shape, not a thin plate on a flat plate. As shown in the figure, the position where the deformation adding jig 2 is tilted from the horizontal position by an arbitrary angle θ is set as a reference position, and the swinging can be performed easily about this position because of the characteristics of the step motor.

Next, FIG. 13 shows an example of a repetitive twisting test of a round bar and a ratcheting test by simultaneous loading of repetitive twisting and shaft pulling load. As shown in the plan view of FIG. 13A, the test piece 26 and the test piece fixture 3 are installed in a straight line in the longitudinal direction of the step motor shaft.
As shown in the side view of (b), the test piece fixture 3 is installed on the base plate 16 via the roller 24. A coil spring 25 for pulling the test piece fixture 3 in the axial direction of the test piece is installed. The coil spring 25 can be removed to repeatedly perform the torsion test, and the ratcheting test can be performed by repeatedly applying the torsional deformation to the test piece while applying the axial tensile load to the test piece.

[0062]

As described above, according to the present invention, it is possible to provide a small-sized material strength reliability evaluation test device having an extremely simple structure and high accuracy, and its control can be carried out by an ordinary personal computer having a relatively small capacity. It becomes possible to control. Also, it becomes possible to observe and monitor the condition of the surface of the test piece online during the reliability evaluation test.

[Brief description of drawings]

FIG. 1 is a plan view showing the structure and arrangement of a step motor, a test piece fixture, and a deformation adding jig of a test apparatus.

FIG. 2 Side view of the above

FIG. 3 is a front view of the above.

FIG. 4 is a diagram showing a loop-type load measuring unit of a thin plate 6 for supporting a test piece fixture.

FIG. 5 is a front view showing how the non-contact displacement gauge is attached.

FIG. 6 is a partial plan view of the same plane and side view.

FIG. 7 is an explanatory diagram of overshoot when driving a step motor.

FIG. 8 is an explanatory diagram of step motor dynamic characteristics when sampling / feedback processing is not performed.

FIG. 9 is an explanatory diagram of sampling feedback processing.

FIG. 10 is a side view of the microscope mounting table.

FIG. 11 is a plan view of the above.

FIG. 12 is a diagram showing a fatigue test of a thin plate having a bend.

FIG. 13 is a block diagram of a repeated twisting and ratcheting test.

[Explanation of symbols]

1 Step motor 2 Deformation addition jig 3 Specimen fixture 4 Step motor shaft 5 Specimen retainer plate 6 Specimen fixture support thin plate 7 Loop type load measuring unit 8 Sliding rail 9 Specimen fixture mount 10 Push Bolt 11 Micro head 12 Non-contact displacement gauge 13 Non-contact displacement gauge support plate 14 Micro head 15 Non-contact displacement mount 16 Base plate 17 Micro movement mechanism in X and Y directions of microscope setting table 18 Z direction micro movement mechanism same as above 19 Optical microscope 20 Pin for supporting rear leg of microscope setting table 21 Front leg of table for same as above 22 Fine movement knob for X direction 23 Fine movement knob for Y direction 24 Roller 25 Coil spring 26 Test piece 100 Tester body

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Shizuo Suzuki Inventor 5-5-1 Chuodai Iino, Iwaki City, Fukushima Prefecture Iwaki Meisei University (72) Norio Kanno, No. 1 Tsukinogawa, Sakura Subscript, Fukushima City, Fukushima Prefecture No. 3 inside Fukushima High-Tech Plaza Fukushima Technical Support Center

Claims (12)

[Claims] 1. A thin plate having a test apparatus main body, a test piece fixture supported by the main body, and a deformation adding jig for deforming the test piece and having a plate thickness of about 0.3 to 3.0 mm. Alternatively, in a strength reliability evaluation test device for evaluating strength reliability of a material by repeatedly applying deformation to a small diameter rod or coil having a diameter of about 0.3 to 3.0φ, a test piece is repeatedly deformed with a constant amplitude. A strength reliability evaluation test device, comprising: a motor as a drive source for driving the motor; and a deformation adding jig that is directly connected to the shaft of the motor and directly transmits the repeated constant amplitude deformation to a test piece. 2. The strength reliability evaluation test apparatus according to claim 1, wherein the motor is a step motor, an ultrasonic motor, or a D motor.
A strength reliability evaluation test device characterized by being either a C servo motor or an AC servo motor. 3. The strength reliability evaluation test apparatus according to claim 1, wherein the test piece fixture is supported via two thin plates. 4. A thin plate having a test apparatus main body, a test piece fixing tool supported by the main body, a deformation adding jig for deforming the test piece, and having a plate thickness of about 0.3 to 3.0 mm. Alternatively, in a strength reliability evaluation test device for evaluating strength reliability of a material by repeatedly deforming a small diameter rod or a coil having a diameter of about 0.3 to 3.0φ, the test piece fixed by a micro head is fixed. Tool, a step motor as a drive source for repeatedly applying deformation to the test piece at a constant amplitude, and the deformation adding jig directly connected to the shaft of the motor, and the deformation adding jig is provided from the center of the motor shaft. from the distance l ₁ and the motor shaft center to the inner end surface when the distance l ₂ to the inner end surface of the test piece fixture, l ₁ and l ₂
The strength reliability evaluation test device is characterized by setting the variable. 5. A thin plate having a test apparatus main body, a test piece fixing tool supported by the main body, a deformation adding jig for deforming the test piece, and having a plate thickness of about 0.3 to 3.0 mm. Alternatively, in a strength reliability evaluation test device for evaluating strength reliability of a material by repeatedly applying deformation to a small diameter rod or coil having a diameter of about 0.3 to 3.0φ, a test piece is repeatedly deformed with a constant amplitude. A stepping motor as a drive source for controlling the deformation, the deformation adding jig directly connected to the shaft of the motor, and a non-contact displacement meter for measuring the displacement of the test piece, and refer to the output of the displacement meter. Strength reliability evaluation test equipment characterized by having a control function (hereinafter referred to as "sampling / feedback control function") that increases the displacement amplitude up to a set value and repeatedly deforms while keeping this amplitude constant. . 6. The strength reliability evaluation test apparatus according to claim 5, wherein the sampling / feedback control function has the following configuration: (1) Target displacement setting input value (± number of input pulses)
Drive the step motor for one cycle to several cycles of repeated displacement, measure the target displacement amplitude with a non-contact displacement meter, and store the result. (2) Set the step motor from the displacement setting input value. Driven with a low input value, increase the number of input pulses while comparing the previously stored target displacement amplitude and measured displacement amplitude with each cycle, and set the difference between the stored target displacement amplitude and measured displacement amplitude to a predetermined value ( For example, 1 / displacement equivalent to one pulse input
Continue driving until 2), (3) Obtain the number of input pulses that satisfy the condition of (2), and drive the step motor for a certain time or a certain number of cycles with the number of pulses, (4) For a predetermined time or for a predetermined period Perform sampling feedback control again after the number of cycles has elapsed. 7. A thin plate having a test apparatus main body, a test piece fixture supported by the main body, and a deformation adding jig for deforming the test piece and having a plate thickness of about 0.3 to 3.0 mm. Alternatively, in a strength reliability evaluation test apparatus for evaluating strength reliability of a material by repeatedly applying deformation to a small diameter rod or coil having a diameter of about 0.3 to 3 mmφ, in order to repeatedly apply deformation to a test piece at a constant amplitude. A step motor as a drive source, the deformation adding jig directly connected to the shaft of the motor, and a straight line arranged in the longitudinal direction of the axis of the step motor, and installed on the base plate of the test apparatus main body via rollers. The above-mentioned test piece fixture is provided, and a strength reliability evaluation test device is provided. 8. A thin plate having a test apparatus main body, a test piece fixing tool supported by the main body, a deformation adding jig for deforming the test piece, and having a plate thickness of about 0.3 to 3.0 mm. Alternatively, in a strength reliability evaluation test apparatus for evaluating strength reliability of a material by repeatedly applying deformation to a small diameter rod or coil having a diameter of about 0.3 to 3 mmφ, in order to repeatedly apply deformation to a test piece at a constant amplitude. The step motor as a drive source, the deformation adding jig directly connected to the shaft of the motor, and a non-contact deformation meter for measuring the displacement of the test piece are provided. The shaft is installed in the front-back direction with respect to the experimenter side, and the test piece fixture is attached to the base plate of the test apparatus main body through a slide mechanism so that the test piece can be finely adjusted in the longitudinal direction. ,further And bolts and 1/100 mm accuracy strength reliability evaluation test apparatus characterized by being interleaved with the micro heads are placed are fixed Me positioning of. 9. The strength reliability evaluation test apparatus according to claim 8, wherein a non-contact displacement gauge for measuring the bending displacement of the test piece is installed vertically below the deformation adding jig. Evaluation test equipment. 10. The strength reliability evaluation test apparatus according to claim 8, wherein a microscope or a magnifying observation sensor is provided above the test piece, and the sensor is set on a table that can be finely moved in the X, Y, and Z triaxial directions. A strength reliability evaluation test device characterized by the above. 11. The strength reliability evaluation test apparatus according to claim 10, wherein the table has a rear portion (the side far from the experimenter) supported by a pin and front and rear portions supported by a foot so that the table is directed upward with the rear pin as a center. A strength reliability evaluation test device characterized in that it can be rotated and lifted. 12. The strength reliability testing apparatus according to claim 8, wherein the deformation applying jig is 45 °, 90 ° from a horizontal plane.
A strength reliability evaluation test device, which is installed at an arbitrary angle of 140 °, 140 °, etc. and is rocked from this position.