JP2536285B2 - Hybrid material testing machine - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hybrid material testing machine capable of loading a test piece over a wide range of loads and frequencies. More specifically, the present invention relates to a hybrid material testing machine capable of driving a crosshead during a small load and low frequency test and hydraulically driving a load jig during a large load and high frequency test to load a test piece.

[0002]

2. Description of the Related Art Conventionally, a base, a pair of screw pillars standing on the base, a crosshead having both ends screwed to the pair of screw pillars, and a crosshead installed on the crosshead. The first load jig and the second load jig installed facing the first load jig, and the pair of screw columns are rotationally driven to raise and lower the crosshead. 1 and 2
2. Description of the Related Art A so-called screw drive type material testing machine is known, which is provided with a drive mechanism for loading and unloading a test piece by separating and contacting the load jig.

A material testing machine for loading a test piece with a hydraulic actuator is also known. A material testing machine called a so-called universal material testing machine includes a base, a pair of columns standing upright on the platform, a crosshead whose both ends are supported by the pair of columns, and a crosshead. The first load jig installed on the first load jig, the second load jig installed facing the first load jig, and the base being moved up and down to the first load jig.
And a hydraulic ram device for connecting and disconnecting the second load jig. In addition, as this type of hydraulic material testing machine, there is also known a system in which a base is fixed and the first or second load jig is driven by a return hydraulic cylinder.

However, although the screw drive type material testing machine has a large stroke, the load is smaller than that of the universal material testing machine, and it is not suitable for high frequency vibration (fatigue) testing. is there. On the other hand, a hydraulically driven material testing machine such as a universal material testing machine is suitable for applying a large load or for high frequency vibration testing, but is suitable for short load short stroke testing and low frequency testing. Not not.

An object of the present invention is to provide a high performance hybrid material testing machine which has the advantages of the conventional screw driven material testing machine and hydraulic driven material testing machine.

[0005]

The present invention will be described with reference to FIG. 1 showing an embodiment. The present invention is based on a base 1 and a pair of bases 1 erected from the base 1 in the load axis direction. Screw post 2
And the nuts 4 at both ends, which are arranged between the pair of screw columns 2.
A cross head 4 in which a is respectively screwed into the pair of screw columns 2, and a first load jig 7 installed in the cross head 4.
A first load jig 11 installed on the base 1 so as to face the first load jig 7, a drive mechanism 9 for imparting a rotational motion between the screw post 2 and the nut 4a, A hydraulic actuator 10 that drives the first or second load jigs 7 and 11 by hydraulic pressure in the load axis direction to separate and contact the first and second load jigs 7 and 11, and is driven by the hydraulic actuator 10. By providing the load jig 11 with the lock means 12 and 13 for restraining the base 1 or the crosshead 4, the above-mentioned object is achieved.

[0006]

In the small load and low frequency test, the load jig 11 driven by the hydraulic actuator 10 is restrained by the lock means 12, 13 on the base 1 or the crosshead 4, and the drive mechanism 9 is driven.
Gives a rotational movement between the screw post and the nut 4a.
As a result, the crosshead 4 moves in the load axis direction, the load jigs 7 and 11 are brought into contact with each other and the test piece TP is loaded. On the other hand, in a large load and high frequency test, the restraint of the load jig 11 is released, and this is moved in the load axis direction by the hydraulic actuator 10, whereby the load jigs 7 and 11 are brought into contact with each other and the test piece TP is attached. To load. At the preparatory stage of this test, the screw head 2 and the nut 4a can be rotated by the drive mechanism 9 to accurately position the crosshead 4 at a desired position on the screw pillar 2. Then, the crosshead 4 can be restrained in the load axis direction by screwing between the screw column 2 and the nut 4a. Here, since the hydraulic actuator 10 may be provided only on the premise of a large load and high frequency test, even if a hydraulic cylinder is used for the hydraulic actuator 10, its stroke in the load axis direction is short and the hydraulic actuator 10 is installed. The space required in the load axis direction is small. Further, if the screw post 2 is rotated, the stroke of the crosshead 4 can be increased or decreased accordingly.
With the stroke of the crosshead 4, the installation space for the screw column 2, the drive mechanism 9, etc. does not increase. Therefore, according to the present invention, the material testing machine can be made compact in the load axis direction.

Incidentally, in the section of means and action for solving the above problems for explaining the constitution of the present invention, the drawings of the embodiments are used for making the present invention easy to understand. It is not limited to.

[0008]

EXAMPLE An example of the material testing machine according to the present invention will be described with reference to FIGS. The material testing machine shown in FIGS. 1 to 3 includes a base 1, a pair of screw columns 2 standing on the base 1, and a pair of columns 3 also standing on the base 1. 4 is a crosshead, and as shown in FIGS.
Both ends are screwed into a pair of screw columns 2 via and a pair of columns 3 are horizontally mounted on a pair of columns 3 so that they can be gripped by a hydraulic lock mechanism 5. The hydraulic lock mechanism 5 has a well-known structure, and the half-cracked crosshead end portion is tightened or released by the expansion and contraction force of the hydraulic cylinder 51 via the fastening rod 52. A first load jig 7 is attached to the crosshead 4 at a load axis position via a load cell 6A and a universal join 6B. In this embodiment, the first load jig 7 is a hydraulic grip. The upper ends of the pair of screw columns 2 and the pair of columns 3 are supported by the cross yoke 8.

The base 1 is provided with a drive mechanism 9 for the screw column 2. As shown in FIG. 3, the drive mechanism 9 includes a servo motor 91, a belt 92 that transmits the rotational force of the servo motor 91, a worm shaft 93 that is rotationally driven by the belt 92, and is fixed to the lower end of the screw column 2. Worm shaft 93
And a worm gear 94 that meshes with.

The base 1 is also provided with a return hydraulic cylinder 10 coaxially with the load axis, and a piston rod of the hydraulic cylinder 10 has a second load jig facing the first load jig 7. 11 is provided. In this embodiment, the second load jig 11 is a hydraulic grip. A flange 12 is fixed to the piston rod, and this flange 12 is a bolt 13
It can be fixed to the base 1. Reference numeral 14 is a servo valve provided in the hydraulic cylinder 11.

Reference numeral 20 denotes a hydraulic pressure source, which supplies pressure oil to the lock hydraulic cylinder 51, the opening / closing cylinders of the first and second load jigs 7 and 12 and the servo valve 14 via the switching valve group 21. .

FIG. 4 shows a control block for driving and controlling the servo motor 91 and the servo valve 14. Reference numeral 71 is a reference signal generator, which outputs a signal conforming to the load pattern applied to the test piece TP. For example, a sine wave signal is output during a fatigue test. Reference numeral 72 is a servo amplifier, and 73 and 74 are changeover switches that operate in conjunction with each other. The changeover switch 73 selects a feedback signal from the servo motor 91 or a feedback signal from the servo valve 14 and feeds it back to the servo amplifier 72. In addition, the changeover switch 74
Outputs the output signal of the servo amplifier 72 to the servo motor driver 7
5 or the servo valve drive unit 76.

The operation procedure of such a material testing machine will be described. (1) When testing by screw drive method (small load, low frequency test) The flange 12 is fixed to the base 1 by the bolt 13, and the hydraulic cylinder 10 is mechanically locked. On the other hand, the lock mechanism 5 of the crosshead 4 is deactivated and the crosshead 4 is locked.
Keeps the pillar 3 slidable. The height position of the crosshead 4 is determined according to the length of the test piece TP, and the opening / closing cylinders of the upper and lower grips 7, 11 are controlled by the switching valve group 21 to open the grips 7, 11. Both ends of the test piece TP are inserted between the upper and lower grips 7 and 12, and the switching valve group 21 is operated to close the grips 7 and 11 to grip the test piece TP.

A reference signal corresponding to the load pattern is set in the reference signal setting section 71 from an operation panel (not shown), and the changeover switches 73 and 74 are switched to the motor side. When the test start is instructed, the reference signal output from the reference signal generator 71 is input to the servo motor driver 75 via the servo amplifier 72 and the changeover switch 74. Servo amplifier 72
Is fed back with a feedback signal from the servo motor 91, and the servo amplifier 72 outputs a drive command signal according to the reference signal and the feedback signal indicating the drive state of the servo motor 91. As a result, the servomotor 91 drives the screw column 2, that is, the crosshead 4 so as to load the test piece TP with a predetermined load pattern. At this time, since the lower grip 11 is fixed to the base 1 by the flange 12, a load is applied to the test piece TP according to the movement of the crosshead 4. The test piece TP may be installed between the cross yoke 8 and the cross head 4 for testing.

(2) When testing by hydraulic drive system (large load, high frequency test) The bolt 12 is removed, the flange 12 is separated from the base 1, and the hydraulic cylinder 10 is made free. On the other hand, while the lock mechanism 5 of the crosshead 4 remains in the inoperative state, the test piece TP
The height position of the crosshead 4 is adjusted according to the length of the
Tighten. In this state, both ends of the test piece TP are grasped by the upper and lower grips 7 and 11 in the same manner as described above.

Similarly to the above, a reference signal corresponding to the load pattern is set in the reference signal setting section 71, and the changeover switches 73 and 74 are switched to the valve side. When the test start is commanded, the reference signal output from the reference signal generator 71 is input to the servo valve drive unit 76 via the servo amplifier 72 and the changeover switch 74. Servo amplifier 72 has servo valve 1
The servo amplifier 72 outputs a drive command signal according to the reference signal and the feedback signal indicating the drive state of the servo valve 14. As a result, the servo valve 14 drives the return hydraulic cylinder 10, that is, the lower grip 11 so as to load the test piece TP in a predetermined load pattern. At this time, since the crosshead 4 is tightened to the column 3,
A load is applied to the test piece TP according to the movement of the lower grip 11.

As described above, according to this embodiment, the test piece TP is loaded by the screw drive method during a small load (for example, 5 kg) and low frequency (for example, 10 ^-6 Hz) test, and a large load (for example, 100 ton), Since the test piece TP is loaded by a hydraulic drive system during a high frequency (for example, 100 Hz) test, it is possible to perform a test in a much wider load range and frequency range with a single material testing machine as compared with the conventional one.

Further, if the circuit configuration as shown in FIG. 4 is used, only one servo amplifier 72 is required and the configuration becomes simple. Of course, a servo amplifier may be provided in each of the servo motor and the servo valve. With this configuration, it is possible to simultaneously perform screw driving and hydraulic driving to load the test piece TP, and to perform a dynamic test and a static test. The effect that the analysis data for simultaneously performing the above can be obtained is obtained.

Further, according to the structure of this embodiment, the screw column 2 can have a diameter capable of withstanding the maximum load when the test piece is loaded by screw driving, and the column 3 can have a diameter capable of withstanding the maximum load of the hydraulic actuator 10. The diameter of the screw column 3 can be reduced, which is advantageous in terms of cost. Moreover, since a single material tester can perform a wide range of load and frequency tests that conventionally require two material testers, the unit price of one unit is the conventional material tester for low load low frequency test, Even if it is higher than the material testing machine for high load high frequency testing, it can be cheaper than two units.

The hydraulic cylinder 10 is attached to the crosshead 4
Alternatively, the piston rod of the hydraulic cylinder 10 may be fastened to the crosshead 4 and locked when the screw is driven. Further, although the hydraulic cylinder 10 is mechanically locked, it may be hydraulically locked, and the mechanical locking mechanism is not limited to the illustrated example. Further, the hydraulic cylinder 10 may be a single-acting type.

Further, the moving mechanism of the crosshead 4 is not limited to the one shown in the figure, but various structures can be adopted. For example, the screw post 2 cannot be rotated, and the nut 4a is rotated by the drive mechanism provided in the crosshead 4. Alternatively, the cross head 4 may be moved up and down.

The load jig is not limited to the gripper of the embodiment, but may be a platen for compression test, a three-point bending jig, or the like. Further, although the hydraulic lock mechanism 5 tightens the crosshead column 3 during hydraulic drive, the hydraulic lock mechanism 5 is not always necessary when the screw column 2 is used.

[0023]

As described above, according to the present invention,
When testing at low load and low frequency, the crosshead can be driven to load the test piece, and at testing at high load and high frequency, the load jig can be driven by hydraulic pressure to load the test piece. A wide range of loads and frequencies can be tested with high precision using a material testing machine on a stand. Moreover, since the configuration in which the crosshead is driven by giving a rotational motion between the screw column and the nut in the crosshead and the configuration in which the pair of load jigs are separated and brought into contact with each other by hydraulic pressure are combined, Can be compactly configured in any direction. Also, when performing a large load, high frequency test, the crosshead can be easily and accurately positioned at a desired position in the load axis direction and restrained at that position, and a small load, low frequency test can be performed. Can be restrained by a lock means so that a load jig driven by hydraulic pressure does not move up and down.

[Brief description of drawings]

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

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a sectional view taken along line III-III of FIG. 1;

FIG. 4 is a control block diagram of FIG. 1.

[Explanation of symbols]

 1 Base 2 Screw Pillar 3 Strut 4 Crosshead 5 Hydraulic Lock Mechanism 7 Upper Grip 9 Screw Drive Mechanism 10 Hydraulic Cylinder 11 Lower Grip 12 Flange 14 Servo Valve 71 Reference Signal Generator 72 Servo Amplifier 73, 74 Changeover Switch 91 Servo motor

Claims (1)

(57) [Claims] 1. A base, a pair of screw pillars erected from the base in the load axis direction, and nuts at both ends arranged between the pair of screw pillars screwed into the pair of screw pillars, respectively. Crosshead, a first load jig installed on the crosshead, a second load jig installed on the base opposite to the first load jig, the screw post, and A drive mechanism for imparting rotational motion between the nut and the nut; a hydraulic actuator for driving the first or second load jig in the load axis direction with hydraulic pressure to separate and contact the first and second load jigs; A hybrid material testing machine, comprising: a lock means for restraining a load jig driven by a hydraulic actuator to the base or the crosshead.