KR20010074286A - Fatigue testing machine by using a tubular linear servo motor - Google Patents

Abstract

PURPOSE: A fatigue testing machine using a tubular linear servo motor is provided to test various test piece at super-high speed and super-high accuracy and maintain high accuracy by preventing backlash. CONSTITUTION: A fatigue testing machine using a tubular linear servo motor includes a table(4) fixed at the upper part of a main body, lower end parts of vertical columns(6,8) axially installed at both sides of the table, a cross head(10) coupled with the middle parts of the columns, an upper head(12) installed at the upper end part of the columns for supporting the columns to be rotated, a load cell(14) fixed at the center of the bottom surface of the cross head, an upper jig(18) detachably installed at the lower part of the load cell for fixing the upper part of a test piece(16), the tubular linear servo motor(22) fixed at the center of the bottom surface of the table under the control of a controller(20) having a rod(24) protruded to the upper part passing through a through hole of the table, and a lower jig(26) detachably installed at the end part of the rod for fixing the lower part of the test piece.

Description

Fatigue testing machine by using a tubular linear servo motor}

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a fatigue testing machine for testing the fatigue of specimens made of metal, rubber, plastic, ceramics, fibers, and the like. Specifically, a load cell and a displacement transducer are mounted. Compact, lightweight, and without backlash, ultra-fast and ultra-precise operation is possible, and a pump and oil / pneumatic facility are not required, and a tubular linear servo motor that can realize full operation by power supply alone is used. The fatigue rate of various specimens can be tested at high speed and ultra precision.

In general, fatigue tests used to measure the fatigue limit of various materials include repeated bending, repeated tensile compression, repeated twisting, and repeated impact test.

Conventional fatigue tester has been designed and used fatigue tester such as hydraulic servo method, rack and pinion gear type servo motor, pneumatic servo method, and look at the characteristics there are many differences according to each method as shown in Table 1 below Able to know.

Rack and Pinion Gear Hydraulic Servo Type Pneumatic Servo Test speed 254 mm / sec 254 mm / sec 500 mm / sec Precision wheat dildo 0.025 mm 0.25 mm 2.5 mm efficiency 40% 25% 25% noise 80 ㏈ 120㏈ 120㏈ Remarks Low speed, noisy Low speed, noise, high price High Noise, Medium Speed, Precise

Looking at the test speed, the rack and pinion gear method and the hydraulic servo method (different depending on the hydraulic source) are relatively low at 254 mm / sec, and the pneumatic servo method has a rack and pinion gear method with a test speed of 500 mm / sec. It is faster than hydraulic and hydraulic servos, but it is still slower in today's world.

In the case of the hydraulic servo method, it is possible to improve the test speed by increasing the hydraulic pressure, but the volume and weight increase, and most of all, it is unrealistic because the cost increases.

In addition, the test accuracy (testing accuracy), the hydraulic servo method is 0.25mm normal precision, and the pneumatic servo method is greatly reduced precision to 2.5mm, both of which generates a loud noise of 120㏈ which greatly exceeds the environmental standard value. A multi-stage silencer can be used to reduce the noise, but it takes a lot of cost. The rack and pinion gear method is 0.025 mm, which is excellent in precision but relatively high in noise, and has a disadvantage in that the test speed is significantly lowered as described above.

In addition, the rack and pinion gear method is 40%, the hydraulic servo method is 25%, and the pneumatic servo method is 25% in terms of efficiency according to the fatigue test, and other peripheral devices for driving the actuator, such as an oil tank Oil Tank, Oil Gauge, Oil Supply Port, Pump Motor, Filter, Valve, Gear Pump, Servo Valve Pipes, hoses, safety valves, pressure regulating valves, load pumps, load control valves, etc. for forming air flow paths, etc., and the like, which is complicated in structure and expensive.

Therefore, the present invention is compact and lightweight, ultra-fast, ultra-precision operation is possible, there is no backlash (backlash caused by looseness between parts), high precision is maintained, and the pump and oil and pneumatic facilities are not necessary, so that the whole power supply only It is an object of the present invention to provide a fatigue tester capable of performing ultra-fast and ultra-precise testing of fatigue of various specimens by using a tubular linear servo motor capable of realizing operation.

Since the tubular linear servo motor is low noise, it is environmentally friendly, and there is no driving part because there is no contact part, so the failure rate is low, and the control at high frequency enables the high speed and high precision fatigue test to be greatly improved.

In addition, the present invention is a fatigue tester of the digital servo control method that can use the tubular linear servo motor (tubular linear servo motor) as the actuator of the fatigue tester to perform fatigue test, tensile test, compression test and bending test of various materials, etc. It consists of a load frame, a load cell, a tubular linear servomotor with position and speed sensors, a controller, A / D and D / A transducers, and a variety of fixtures for operating programs and specimens.

In addition, the present invention by attaching the encoder to a non-contact tubular linear servomotor to control the position (displacement) and speed, it is possible to precisely control the load at a high speed using a load cell.

The controller can be controlled manually as an open rod, and can control PID when it is closed, and digitally control the load, position and speed through an A / D converter, and the A / D converter is It will be possible to control the tester and acquire data.

Operation program refers to all programs that can operate a fatigue tester as a computer.The various fixtures (eg jigs or clamps) for fixing specimens consist of grips for tensile tests, compression plates for compression tests, and bending plates for bending tests. do.

In the present invention, the clamping means for fixing the specimen may use a metalwood method that may be firmly fixed by using a bolt nut or by using a temperature difference to harden the end and the jig of the specimen.

1: Front view of the present invention.

2 is a longitudinal cross-sectional view of the present invention.

3 is a cross-sectional view of the power transmission portion of the present invention.

4 is a test state diagram presented as an embodiment in the present invention.

5 is a cross-sectional view of an embodiment of a tubular linear servomotor of the present invention.

6 is a control circuit block diagram of a tubular linear servomotor of the present invention.

<Explanation of symbols for the main parts of the drawings>

(2)-fatigue tester (4)-body

(6) (8)-Column (10)-Crosshead

(12)-Upper Head (14)-Load Cell (Load Counter)

(16)-Psalm (18) (26)-Jigsaw Fixture

(20)-controller (22)-tubular linear servomotor

(24)-Rod (25) (38)-Chain

(28) (30) (32) (36)-Chain Gears (34)-Servo Motor

(40)-Stopper (41)-Control Panel

(42)-caster (44)-clamping switch

(46)-Unclamp switch (48)-Crosshead lift button

(50)-Crosshead Lower Button (52)-Emergency Stop Button

(54)-Test Speed Variable Switch (56)-Test Count Setting Switch

(58)-Power Switch (60)-Bolt

(62)-Nut (82) (84)-Input (88) (96)-Amp

(90)-A / D Converter (92) (94)-PID Control Unit

(98)-Encoder

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

As described above, the present invention is compact and lightweight, and allows for high speed and high precision fatigue test, and there is no backlash (backlash caused by looseness between parts), so that high precision is maintained and pump and oil and pneumatic facilities are unnecessary. By using a tubular linear servo motor as an actuator that can realize full operation by power supply, it is possible to test the fatigue of various specimens at high speed and ultra precision.

The present invention relates to a tubular linear servomotor as a fatigue test actuator, a load frame, a load cell, a position and speed sensor for controlling position and speed, a controller for controlling the fatigue tester, and a / Consists of D, D / A converter, operation program and various fixtures for specimen fixing. The tubular linear servomotor is low noise, environmentally friendly, non-contact type, so there is no driving part. And the performance is greatly improved, which enables ultra-high speed and high precision fatigue test, and fatigue test, tensile test, compression test and bending test of various materials.

1, 2, and 3 are cross-sectional configuration diagrams of the fatigue tester 2 of the present invention.

The table 4 is fixed to the upper part of the main body 4, the lower end of the vertical column 6, 8 comprised by a pair on both sides of the said table 4 is axially installed, and the said column 6, 8 The crosshead 10 is screwed into the middle portion of the top, and the upper head 12 is installed at the upper end of the column (6) (8) to support the column (6) (8) to rotate.

A high precision load cell (loadmeter: 14) is fixed to the center of the bottom surface of the crosshead 10, and an upper jig 18 for fixing the upper part of the specimen 16 is fixed to the lower part of the load cell 14 in a detachable structure. Is installed.

The tubular linear servomotor 22 under the control of the controller 20 is fixed to the center of the bottom surface of the table 4, and the sunken rod 24 of the tubular linear servomotor 22 is formed on the table 4. The lower jig 26 is fixed to the upper portion of the table 4 through the through hole, and the lower jig 26 for fixing the lower portion of the specimen 16 is installed at the end of the rod 24.

The tubular linear servomotor 22 used as the fatigue test actuator in the present invention is ultra-fast, ultra-precise, compact and lightweight, and has no backlash (backlash: backlash caused by looseness between parts) to maintain high precision, and the pump and oil ㆍ Pneumatic facility is unnecessary, so the whole operation can be realized only by supplying power.

In addition, since the tubular linear servomotor 22 is low noise, it is environmentally friendly, and there is no driving part because there is no contact part, so the failure rate is low, and it is controlled by using a high frequency (several to several hundreds of kW), so that the test speed and performance (precision) ) Is greatly improved, and ultra-high speed and high precision fatigue test is possible.

Meanwhile, chain gears 28 and 30 connected to the chain 25 are respectively fixed to the lower shafts of the columns 6 and 8, and another chain gear 32 is fixed to the lower end of one column 6. The chain gear 36 is fixed to the rotary shaft rod of the servomotor 34 fixed to the main body 4, and the chain gears 32 and 36 are connected to the chain 38 to form a column 6, 8. ) Is configured to rotate in the same direction.

Therefore, when the servo motor 34 is controlled by the controller 20, the rotational force of the servomotor 34 is transmitted to cause the columns 6 and 8 to interlock and rotate in accordance with the rotation of the columns 6 and 8. Since the head 10 is raised or lowered, the height of the cross head 10 is appropriately adjusted according to the height of the specimen 16.

The lower part of the main body 4 is provided with a plurality of casters 42 having a stopper 40, it is easy to move the position of the fatigue tester (2).

In the present invention, the control panel (41) connected to the controller 20 in the jig 18, 26 clamping switch 44, jig (18) (26) unclamp switch 46, crosshead lift button ( 48), crosshead lowering button 50, emergency stop button 52, test speed variable switch 54, test frequency setting switch 56, power switch 58, stroke setting switch and the like. It is composed.

On the other hand, Figure 5 is a cross-sectional configuration of the tubular linear servomotor 22 of the present invention, the state coil 76 is located in the interior of the body 74, the heat dissipation fin 72 is wrapped around the rod (amateur) 24 is installed to be able to move in the longitudinal direction, the portion of the body 74 and the armature rod 24 is in contact with the Steve bearing 78 is installed, respectively, the operating power and control signal to one side of the body 74 The supplied electrical connector 80 is installed, and an encoder 98 for sensing the position and speed of the rod 24 is also installed.

The speed, stroke S, pressure and load of the tubular linear servomotor 22 are determined according to the control signal of the controller and the peripheral control circuit as shown in FIG. FIG. 6 is a block diagram of a control circuit of the tubular linear servomotor 22 in one embodiment.

The controller (or computer) 20 to which the control panel 41 is connected is inputted with the position signal and the speed signal through the interface and the input 1 82, and the pressure signal and the load signal through the input 2 84.

The operational load of the tubular linear servomotor 22 is detected by a load cell (loadmeter: 14), then amplified by an amplifier 88, converted into a digital signal by the A / D converter 90, and then PID by the PID controller 92. The fatigue of the specimen 16 is tested with the set load to be controlled.

In addition, the position signal and the speed signal applied from the controller 20 are amplified by the PID controller 94 and then applied to the tubular linear servomotor 22 to determine the test speed and the operating stroke of the amateur rod 24. The movement speed (test speed) and the stroke of the amateur rod 24 are precisely controlled by the encoder 98 which detects the position and the speed of the amateur rod 24.

That is, the encoder 98 precisely detects the position and the speed of the armature rod 24 with a pulse and feeds it back to the input 2 82 so as to control the PID, so that the movement speed (test speed) and the stroke of the armature rod 24 are precise. Controlled.

As described above, the armature rod 24 of the tubular linear servomotor 22 is subjected to a test that gives fatigue to the specimen 16 while piercing at a set position (stroke), speed, pressure, and load.

In addition, the controller 920 is capable of manual control as an open rod and PID control in a closed state, and digitally controls the load, position, and speed via the A / D converter 80.

In the present invention, the jig 14, 26 to which both ends of the specimen 16 are fixed is fixed to the specimen 16 using the bolts 60 and the nut 62 as shown in FIG. 4 or Wood's Alloy using a temperature difference. It is possible to fix the specimen 16 by the grip method using).

When pressurized to about 100 ° C. using the wood metal heating device, the liquid state is changed into liquid state. The specimen 16 is immersed in the liquid wood metal, and then cooled by a cooling device to lower the temperature to room temperature. As it hardens, the specimen 16 is firmly fixed.

In the present invention, the servo mechanism (servo mechanism) refers to a mechanism that automatically follows the output (position, direction, angle, etc.) to reach a predetermined target value when the input of the device to be controlled changes arbitrarily.

On the other hand, the speed and performance of the present invention is shown in Table 2 below.

The stroke and speed of the armature rod 24 vary depending on the frequency of the control power supply applied to the tubular linear servomotor 22.

For example, when 4.4 ㎐ control power is applied, the stroke of the armature rod 24 is about ± 100 mm, and the test speed is ± 1,616 mm /, which is a multiple of 4 times the product of the stroke (± 100 mm) and the frequency (4.4 ㎐). sec.

When the control power is applied at 76 kHz, the stroke is approximately ± 3 mm and the test speed is ± 912 mm / sec, which is a multiple of four times the product of the stroke (± 3 mm) and the frequency (76 kHz).

Therefore, the speed and the stroke of the tubular linear servomotor 22 can be determined by controlling the operating frequency.

Stroke Frequency (Hz) ± 100 mm 4.4 ± 25 mm 18 ± 3 mm 76

In the present invention, reference numeral 64 is a metal bearing, 66 is a bolt, 68 is an eye bolt 70 is a support plate.

Table 3 below compares the speed, accuracy, efficiency, noise, and the like of the fatigue tester of the present invention and the fatigue tester of the present invention, respectively.

Rack and Pinion Gear Hydraulic servo system Pneumatic Servo Tubular linear servomotor method Test speed 254 mm / sec 254 mm / sec 500 mm / sec 2540 mm / sec Degree 0.025 mm 0.25 mm 2.5 mm 0.025 mm efficiency 40% 25% 25% 50% noise 80 ㏈ 120㏈ 120㏈ 40㏈ Remarks Low speed, noisy Low speed, noise, high price Non-precision High speed (high frequency) high accuracy, low noise

In other words, the rack and pinion gear method and the hydraulic servo method (slightly different depending on the hydraulic source) at the test speed are 254 mm / sec and the pneumatic servo method is 500 mm / sec. In this case, the test time is 5 to 10 times faster than the conventional methods at 2,540 mm / sec, which shortens the test time.

Since the tubular linear servomotor of the present invention is controlled at a high frequency, speed of the test speed can be achieved.

In addition, even in the test accuracy (test accuracy), it can be seen that the precision of the tubular linear servomotor method having a precision of 0.25 mm for the hydraulic servo method and 2.5 mm for the pneumatic servo method and 0.025 mm is significantly lower than the present invention.

In addition, in terms of efficiency, the rack and pinion gear method is 40%, the hydraulic servo method is 25%, the pneumatic servo method is 25%, the present invention of the tubular linear servo motor method is improved in terms of efficiency to 50%.

In addition, in terms of noise generation, the hydraulic servo and pneumatic servo methods are 120 kV, which is significantly higher than the environmental standard. The rack and pinion gear system is 80 kV and the present invention of the tubular linear servomotor method is very low, 40 kV. It can be seen.

In addition, the hydraulic servo method has the disadvantage of low speed, high noise, and high cost. The pneumatic servo method greatly reduces the precision and generates noise of 120㏈, significantly exceeding the environmental standard, and the rack and pinion gear method of 80㏈. A relatively loud noise is generated, and the present invention of the tubular linear servomotor method is very low as 40 kHz.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications, and changes may be possible without departing from the technical spirit of the present invention, which is a technology to which the present invention pertains. It is obvious to those of ordinary skill in the field.

As described above, the present invention can test the fatigue of various specimens at a very high speed and high precision by using a tubular linear servomotor capable of precise high speed control with a small size, light weight, power supply, and is tested only by supplying power since the driving source of the tubular linear servomotor is power. As a result, hydraulic and pneumatic facilities and devices are unnecessary, so that the size and weight can be reduced.

In addition, backlash caused by looseness between components is prevented, and high accuracy is maintained.

In addition, the tubular linear servo motor of the present invention is low noise, environmentally friendly, non-contact type, there is no failure rate, there is no failure rate, and the use of high frequency, the speed and performance is greatly improved, ultra-fast, ultra-precision fatigue of the specimen It is possible to test.

The tubular linear servomotor equipped with a load cell, position sensor and speed sensor has the effect of controlling the position (displacement) and speed by attaching an encoder to a non-contact tubular linear servomotor, and precisely controlling the load at high speed by attaching a load cell. have.

Further, the controller of the present invention is a useful invention in which manual control is possible as an open rod and PID control can be performed in a closed state.

Claims (3)

Fatigue tester which controls the height of the cross head by the forward and reverse rotation of the column and fatigue test the specimen fixed to the jig with the actuator.It is fixed to the tubular linear servomotor table which can control the ultra-high speed and ultra-precision motion by frequency control method. A fatigue tester using a tubular linear servomotor which is used as a fatigue test actuator and is provided with a jig attached to and detached from the armature rod end of the tubular linear servomotor. The tubular linear servomotor of claim 1, wherein a state coil is positioned inside the body in which the heat dissipation fins are enclosed, and an amateur rod is installed in the longitudinal direction, and the bearing is connected to the body and the amateur rod. And an encoder that detects the position and the speed of the armature rod, and a connector for supplying the operating power and control signal to one side of the body, and a fatigue tester using a tubular linear servomotor. A load cell for detecting an operating load of a tubular linear servomotor, an amplifier and an A / D converter for amplifying the load of the load cell and converting the detected load into a digital signal, and converting the digital conversion signal into a PID. PID controller for controlling, position signal, speed signal of controller and other PID controller for PID control of the PID control signal, amplifier for amplifying PID control signal to control tubular linear servomotor, and amateur rod of tubular linear servomotor Fatigue tester using a tubular linear servomotor consisting of an encoder that senses the position and speed of the sensor and feeds back and controls it.