JPH1062327A - Material testing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To load a test piece by a stroke larger than an electromagnetic actuator in a material testing machine for repeatedly loading the test piece. SOLUTION: In addition to an electromagnetic actuator 9 for repeatedly loading a test piece T, this device has a servo motor 10 for rotating a screw beam 6 to which a movable yoke 8 is screwed to vertically move the movable yoke 8. When the test piece T is loaded by a relatively short stroke, the electromagnetic actuator 9 is driven, and when the test piece T is loaded by a relatively large stroke, the servo motor 10 is driven to rotate the screw beam 6, and the movable yoke 8 is vertically moved to load the test piece T.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a material testing machine for statically or repeatedly loading a specimen to evaluate the strength characteristics of the specimen.

[0002]

2. Description of the Related Art There is known a material testing machine for applying a load or displacement having an arbitrary test waveform to a test piece to perform a fatigue test of a test piece. Such a material testing machine has a configuration in which a yoke is horizontally mounted on upper ends of a plurality of columns erected on a base and a movable yoke that can move up and down is attached. The base is provided with, for example, an electromagnetic actuator.A jig for gripping the specimen is attached to the actuator and the movable yoke to grip the specimen, and the actuator is controlled to vibrate according to an arbitrary test waveform. Then, the fatigue characteristics of the specimen are measured by repeatedly applying a displacement or a load to the specimen at a frequency of about 0.1 to 100 Hz.

[0003]

However, in the material testing machine provided with the above-mentioned electromagnetic actuator, the driving range of the actuator is as small as 10 mm or less, and for example, the elongation of rubber, strands and the like is relatively large. When the specimen is tested, the material properties of the specimen cannot be measured because the elongation range of the specimen is larger than the driving range of the actuator. In addition, a material testing machine that statically tests a specimen by driving a movable yoke by rotating a screw rod and a movable yoke by screwing the screw rod and a movable yoke upright on a base, and rotating the screw rod. Although it is also known, it is difficult to perform a dynamic test of a minute displacement and a minute load as described above.

On the other hand, when testing specimens having different lengths using a material testing machine having the above-described electromagnetic actuator, it is necessary to change the distance between the upper and lower grips. For this reason,
Conventionally, the movable yoke is manually moved up and down to adjust the position of the upper grip. However, it is difficult to move the movable yoke up and down manually, and it is difficult to accurately perform the positioning, which is very troublesome.

Further, when the load rod of the electromagnetic actuator is supported by the linear bearing, there is a problem that a measurement error due to the support resistance is large.

An object of the present invention is to provide a material testing machine capable of performing both a dynamic or static test by a minute load and a minute displacement and a static test by a displacement larger than that. Another object of the present invention is to provide a material testing machine capable of accurately applying a specimen in a test using a minute load and a minute displacement.

[0007]

FIG. 1 shows an embodiment of the present invention.
Referring to FIG. 4, the invention of claim 1 is based on the bases 2 and 4 and the plurality of columns 5 </ b> A to 5 erected on the bases 2 and 4.
C, a screw rod 6 erected on the bases 2 and 4, a movable yoke 8 screwed to the screw rod 6, and movably suspended vertically on each of the columns 5 </ b> A to 5 </ b> C. An electromagnetic loading means 9 for loading the specimen T with the first stroke, and the movable yoke 8 being moved up and down by rotating the screw rod 6 to load the specimen T with a second stroke larger than the first stroke. The above object is achieved by providing a screw-type load means 10 to be loaded and a control means 30 for controlling the driving of the electromagnetic load means 9 and the screw-type load means 10 according to the load conditions on the specimen T.

According to a second aspect of the present invention, the control means 30 detects the displacement of the electromagnetic load means 9 by the first displacement detecting section 21.
A first load detector 19 for detecting a load on the specimen T by the electromagnetic load means 9, and an electromagnetic load based on detection results by the first displacement detector 21 and the first load detector 19. First control units 37 and 41 for controlling the load of the means 9
A second displacement detector 11 for detecting a displacement of the screw-type load means 10, a second load detector 19 for detecting a load on the specimen T by the screw-type load means 10, and a second displacement detection It comprises second control units 36 and 40 for controlling the load of the screw-type load means 10 based on the detection result by the unit 11 and the second load detection unit 19.

According to a third aspect of the present invention, there are provided bases 2 and 4, a plurality of columns 5A to 5C erected on the bases 2 and 4,
A movable yoke 8 laid on the A to 5C so as to be movable up and down, a movable part 12 for loading the specimen T, which can move up and down linearly;
The above object is achieved by further applying a support member having a leaf spring 14 for supporting the upper and lower ends of the movable parts 12 and 13 which is applied to a material testing machine having the electromagnetic load means 9 having the electromagnetic load means 13. I do.

According to the first aspect of the present invention, the control means 30 controls the electromagnetic load means 9 to load the specimen T with a relatively small stroke, and performs a fatigue test on the specimen T. On the other hand, the screw type load means 1 is controlled by the control means 30.
A test is performed in which the specimen T is loaded by moving the movable yoke 8 up and down while controlling 0.

According to the second aspect of the present invention, the displacement of the electromagnetic load means 9 is changed by the first displacement detecting section 21, and the load on the specimen T by the electromagnetic load means 9 is changed by the first load detecting section 19. Is detected, and based on the detection result, the first control unit 3
7, 41 control the load on the electromagnetic load means 9. Further, the displacement of the screw type load means 10 is changed by the second displacement detection section 11 and the screw type load means 1 is changed by the second load detection section 19.
A load on the test piece T of 0 is detected, and the second control units 36 and 40 control the load on the screw-type load means 10 based on the detection result.

According to the third aspect of the present invention, when a load is applied to the specimen T, the ends of the movable parts 12, 13 are supported by the leaf springs 14, so that the plate is moved in accordance with the movement of the movable parts 12, 13. The spring 14 moves while flexing.

In the section of the means for solving the above-mentioned problems, which explains the configuration of the present invention, the drawings of the embodiments of the present invention are used to make the present invention easy to understand. However, the present invention is not limited to this.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing a configuration of a material testing machine according to an embodiment of the present invention, and FIG. 2 is a side sectional view thereof. As shown in FIGS. 1 and 2, the tester main body 1 includes a base 2 and four columns 3A to 3
A load table 4 placed on the 3D, three columns 5A to 5C erected on the load table 4, a screw rod 6 erected on the base 2 so as to be rotatable, and three columns 5A to 5D and screw rod 6
Yoke 7 laid on the upper end of the vehicle and three columns 5A to 5C
A movable yoke 8 movably mounted on the base 2 and screwed to the screw rod 6, an electromagnetic actuator 9 mounted on the base 2, and a servomotor 1 for rotating and driving the screw rod 6.
0, an encoder 11 attached to the upper end of the screw rod 6 to detect the number of revolutions of the screw rod 6, and a displacement meter 21 attached to the electromagnetic actuator 9 to detect its displacement. The movable yoke 8 has chucks 20A to 20C.
(The chuck 20C is not shown), and the movable yoke 8 and the support columns 5A to 5C are provided by the chucks 20A to 20C.
Fixation and release from 5C are performed. That is, the movable yokes 8 are tightened by tightening the chucks 20A to 20C.
Are fixed to the supports 5A to 5C, and the chucks 20A to 20C
By loosening the movable yoke 8, the movable yoke 8 can be moved vertically with respect to the columns 5A to 5C.

As shown in FIG. 2, the electromagnetic actuator 9 is provided with a coil 9A and a magnet 9B. When an alternating current is passed through the coil 9A, the output shaft 13 is driven to operate the electromagnetic actuator 9. Can be driven.
A load shaft 12 is attached to the output shaft 13 of the electromagnetic actuator 9 via a joint 13A. The upper end of the load shaft 12 passes through a leaf spring 14 (see FIG. It protrudes above the table 4. The lower end of the output shaft 13 passes through a leaf spring (not shown) provided on the base 1.

As shown in FIG. 3, the leaf spring 14 is
The ring-shaped holding fourth housed in the recess 4A formed in
It is mounted on B by screws 4C. Leaf spring 14
A support hole 14A through which the load shaft 12 penetrates is formed in the center of the support hole 14, and a holder 15 is provided around the support hole 14A. The holder 15 and the load shaft 12 are fixed by screws 16. A plurality of groove portions 14B are formed concentrically around the support hole 14A. Leaf spring 14
Is formed in this manner, while holding the load shaft 12, swings by a predetermined biasing force in the long axis direction of the load shaft 12, and is displaced to some extent in a direction orthogonal to the long axis of the load shaft 12. It is possible to The support hole 14A and the slot 14B are formed by etching or wire cutting. Note that the lower end of the output shaft 13 is also supported by a leaf spring similarly to the upper end of the load shaft 12. Thus, the load shaft 1
2 and the output shaft 13 are supported by the leaf spring 14, so that the sliding resistance can be reduced as compared with the case where the load shaft 12 and the output shaft 13 are supported by linear bearings. Thus, a minute load can be accurately applied.

A lower jig 17 for holding the specimen T is attached to the upper end of the load shaft 12, and an upper jig 18 is attached to the movable yoke 8 via a load cell 19. And
The specimen T is gripped by the lower jig 17 and the upper jig 18.

FIG. 4 is a diagram showing a configuration of a control circuit for controlling the driving of the material testing machine according to the embodiment of the present invention. As shown in FIG. 4, the control circuit 30 includes a servo amplifier 31 for controlling the rotation of the servo motor 10, a yoke movement amount amplifier 32 connected to the encoder 11, and a load cell 19.
, A displacement amplifier 34 connected to the displacement meter 21 for detecting the displacement of the output shaft 13, a power amplifier 35 connected to the electromagnetic actuator 9,
A signal output unit 36 for outputting a control signal for driving the servomotor 10; a signal output unit 37 for outputting a control signal for driving the electromagnetic actuator 9; , A switch 39 for switching the drive of the electromagnetic actuator 9 to control by load or control by displacement, a control signal output from the signal output unit 36 and the movement amount amplifier 32 or A differentiator 40 for calculating a difference between the detection signal output from the load amplifier 33 and a difference between the control signal output from the signal output unit 37 and the detection signal output from the displacement amplifier 34 or the load amplifier 33. And a differentiator 41. Further, the movable yoke 8 is provided in the servo amplifier 31 as described later.
Switch 31A for moving up and down is connected.

Next, the operation of the present embodiment will be described. In the present embodiment, a tensile pulsating test in which a load is repeatedly applied with the amplitude Fa only in the positive direction with the load average value Fm of the specimen T as a positive value is performed while controlling the load applied to the specimen T. Shall be. First, the changeover switch 31A is turned on, the movable yoke 8 is moved up and down according to the length of the test piece T, and after the movable yoke 8 reaches a desired position, the changeover switch 31A is turned off. Is attached to the lower jig 17 and the upper jig 18. Thereafter, the changeover switch 38 is switched to the b side, and the signal output unit 3
From 6, a signal is output so as to apply a predetermined tensile load Fm to the specimen T. As a result, the servomotor 10 is driven to rotate the screw rod 6 and move the movable yoke 8 upward. At this time, if the output shaft 13 and the load shaft 12 move upward, a desired load cannot be applied to the specimen T, so that the power amplifier 35 sets the signal detected by the displacement meter 21 to zero. Electromagnetic actuator 9
And the displacement of the output shaft 13 and the load shaft 12 is set to zero. Therefore, the test piece T is pulled upward, whereby a tensile load acts on the test piece T. Then, the tensile load acting on the specimen T is detected by the load cell 19, and the detection signal is input to the differentiator 40 via the load amplifier 33. In the differentiator 40, a difference value between the signal output from the signal output unit 36 and the signal output from the load amplifier 33 is calculated. Then, when the difference value becomes 0, the signal output unit 36 stops outputting the signal. As a result, the specimen T is loaded with the load average value Fm.

Next, the changeover switch 39 is switched to the "a" side, and the signal output section 37 outputs a sine wave signal as shown in FIG. As a result, the power amplifier 35 drives the electromagnetic actuator 9 to repeatedly move the output shaft 13 and the load shaft 12 in the vertical direction, and apply a repetitive load suitable for the specimen T to the sine wave signal shown in FIG. Then, the repetitive load acting on the specimen T is detected by the load cell 19, and the detection signal is transmitted through the load amplifier 33 to the differentiator 4.
1 is input. In the differentiator 41, the signal output unit 3
The difference value between the signal output from 7 and the signal output from the load amplifier 33 is calculated. The differentiator 41 performs control such that the sine wave signal output from the signal output unit 36 is corrected so that the difference value becomes 0, and the sine wave signal is input to the power amplifier 35. As a result, a repetitive load suitable for the sine wave signal output from the signal output unit 36 is applied to the specimen T, and the fatigue test is performed.

Since the load shaft 12 and the output shaft 13 driven by the electromagnetic actuator 9 are supported by the above-described leaf spring 14, the output shaft 13 and the load shaft 12 are supported by linear bearings. Since the frictional resistance at the time of movement is suppressed as compared with the above, it is possible to accurately apply a repeated load to the specimen T.

When a load is applied to the specimen T by driving the movable yoke 8, a tensile force or a compressive force acts on the specimen T, so that the load shaft 12 and the output shaft 13 move vertically. Resulting in. Therefore, in order to prevent the load shaft 12 and the output shaft 13 from moving, the changeover switch 39 is switched to the b side, and a signal for keeping the displacement of the output shaft 13 and the load shaft 12 constant from the signal output unit 37 is output. I do. And during the test,
The displacement of the load shaft 12 and the output shaft 13 is detected by the displacement meter 21, and the detection signal is input to the displacement amplifier 34. The displacement amplifier 34 outputs the input signal to the differentiator 41. The differentiator 41 calculates a difference value between the signal output from the displacement amplifier 34 and the signal output from the signal output unit 37 and representing a displacement as shown in FIG. 6, and inputs the difference value to the signal output unit 37. The signal output unit 37 outputs a signal for driving the electromagnetic actuator 9 to the power amplifier 35 so that the inputted difference value becomes 0, whereby the electromagnetic actuator 9 causes the displacement of the output shaft 13 and the load shaft 12 to be zero.
The output shaft 13 and the load shaft 12 are driven so that
As a result, even when the servomotor 10 is driven to apply a load to the specimen T, the output shaft 13 and the load shaft 12 do not move in response to the reciprocating movement of the movable yoke 8, so that the A load can be accurately applied to the specimen T.

In the above embodiment, the test is performed while controlling the load acting on the specimen T. However, the test may be performed while controlling the displacement of the specimen T. That is, the changeover switch 39 is switched to the b side, the displacement of the load shaft 12 under test is detected by the displacement meter 21, and the detection signal is input to the displacement amplifier 34. The displacement amplifier 34 outputs the input signal to the differentiator 41.
In the differentiator 41, a difference value between the signal output from the displacement amplifier 34 and the sine wave signal representing the displacement as shown in FIG. 7 output from the signal output unit 37 is calculated and input to the power amplifier 35. . The power amplifier 35 outputs a signal for driving the electromagnetic actuator 9 so that the input difference value becomes 0, and the electromagnetic actuator 9
The output shaft 13 and the load shaft 12 are driven so that the displacement of the load shaft 12 conforms to the sine wave signal shown in FIG. Thereby, the fatigue test of the specimen T can be performed while controlling the displacement of the specimen T.

On the other hand, when the test is performed by driving the servo motor 10, the changeover switch 39 is switched to the “a” side, the displacement of the movable yoke 8 is detected by the encoder 11, and the detection signal is input to the movement amount amplifier 32. I do. The movement amount amplifier 32 inputs the input signal to the differentiator 40. The difference unit 40 calculates a difference value between the signal output from the movement amount amplifier 32 and the signal output from the signal output unit 36 and representing a displacement as shown in FIG. 7, and inputs the difference value to the servo amplifier 31. The servo amplifier 31 outputs a signal for driving the servo motor 10 so that the inputted difference value becomes 0, and the servo motor 10 rotates the screw rod 6 so that the displacement of the movable yoke 8 matches the signal. The yoke 8 is driven. Thereby, the specimen T is controlled while controlling the displacement of the specimen T.
Can perform static tests.

As described above, the operation of appropriately switching the changeover switches 38 and 39 by the operator can be automatically performed by a command from the CPU or the like. In this case, when the CPU determines that the load average value or the displacement average value is out of the range of use of the electromagnetic actuator 9, it may be programmed to automatically execute the above-described procedure.

Further, in the above embodiment, the upper end of the load shaft 12 and the lower end of the output shaft 13 are supported by the leaf spring 14, but the specimen T is moved with a stroke exceeding the elastic range of the leaf spring 14. When moved, the leaf spring 1
4 is deformed, and a repeated load cannot be applied accurately. In this case, for example, as shown in FIG.
B and holders 46A, 46B for holding the metal bushes 45A, 45B.
The load shaft 12 and the output shaft 13 may be supported by fitting B with the load shaft 12 and the output shaft 13.
Here, since a certain amount of sliding resistance exists between the metal bushes 45A and 45B and the load shaft 12 and the output shaft 13, the load shaft 12 and the output shaft 13 slide depending on the stroke of the leaf spring 14 within the elastic range. It does not move but reciprocates only by the deflection of the leaf spring 14. On the other hand, when the specimen T is moved by a stroke exceeding the elastic range of the leaf spring 14, the load shaft 12 and the output shaft 13 reciprocate while sliding in the metal bushes 45A and 45B. Accordingly, even if the specimen T is loaded with a stroke exceeding the elastic range of the leaf spring 14, the leaf spring 14 is not deformed, and a repeated load can be accurately applied to the specimen T.

In the correspondence between the above-described embodiment and the claims, the electromagnetic actuator 9 is an electromagnetic load means, the servomotor 10 is a screw type load means, the control circuit 30 is a control means, and the displacement meter 21 is a first load means. 1, the load cell 19 serves as the first and second load detectors, and the signal output unit 37 serves as the load detector.
And a differentiator 41 as a first controller, an encoder 11 as a second displacement detector, a signal output unit 36 and a differentiator 40.
Constitute the second control unit.

[0028]

As described above in detail, according to the first aspect of the present invention, not only the electromagnetic load means but also the screw type load means are provided, so that the movable yoke can be driven by the screw type load means. Thus, the specimen can be loaded with a larger stroke than the electromagnetic loading means. Also,
Even when testing specimens having different lengths, the distance between the upper and lower grips can be easily changed. Furthermore, even when a load is previously applied to the specimen by means other than the electromagnetic loading means, the screw value loading means can be driven by the control means to set the load value. It is not necessary to perform the setting, and the load can be easily set.

According to the third aspect of the present invention, since the movable portion of the electromagnetic load means is supported by the leaf spring, the sliding resistance of the movable portion is reduced as compared with the case where the movable portion is supported by the linear bearing. Thus, the specimen can be accurately loaded.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a configuration of a material testing machine according to an embodiment of the present invention.

FIG. 2 is a side sectional view showing a configuration of a material testing machine according to an embodiment of the present invention.

FIG. 3 is a plan view showing a configuration of a leaf spring.

FIG. 4 is a block diagram illustrating a configuration of a control circuit.

FIG. 5 is a graph showing a load signal.

FIG. 6 is a graph showing a displacement signal of an electromagnetic actuator.

FIG. 7 is a graph showing a displacement signal of a movable yoke.

FIG. 8 is a diagram showing another configuration of a member supporting the load shaft and the output shaft.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Test machine main body 2 Base 5A-5C Prop 6 Screw rod 8 Movable yoke 9 Electromagnetic actuator 10 Servo motor 11 Encoder 12 Load shaft 13 Output shaft 14 Leaf spring 17 Lower jig 18 Upper jig 19 Load cell 21 Displacement meter 30 Control Circuits 36, 37 Signal output unit 40, 41 Difference device

Claims (3)

[Claims] A pedestal; a plurality of columns erected on the pedestal; a screw rod erected on the pedestal; screwed to the screw rod; A movable yoke horizontally laid, an electromagnetic loading means for loading a specimen with a relatively small first stroke, and rotating the screw rod to move the movable yoke up and down. A screw-type load unit that loads the specimen with a second stroke greater than a stroke; and a control unit that controls driving of the electromagnetic load unit and the screw-type load unit in accordance with a load condition on the specimen. A material testing machine comprising: 2. A first displacement detection unit for detecting a displacement of the electromagnetic load unit, a first load detection unit for detecting a load on the specimen by the electromagnetic load unit, A first control unit that controls a load of the electromagnetic load unit based on detection results by the first displacement detection unit and the first load detection unit; and a second control unit that detects displacement of the screw type load unit. 2, a second load detection unit that detects a load on the specimen by the screw-type load unit, and a detection result by the second displacement detection unit and the second load detection unit. And a second controller for controlling the load of said screw type load means.
Material testing machine as described. 3. A base, a plurality of columns erected on the base, a movable yoke suspended on each of the columns so as to be vertically movable, and capable of vertically moving vertically to load a specimen. What is claimed is: 1. A material testing machine comprising: an electromagnetic load unit having a movable part; and a supporting member having a leaf spring for supporting an upper end and a lower end of the movable part.