WO2018229966A1

WO2018229966A1 - Material testing machine

Info

Publication number: WO2018229966A1
Application number: PCT/JP2017/022284
Authority: WO
Inventors: 麻衣子苅田
Original assignee: 株式会社島津製作所
Priority date: 2017-06-16
Filing date: 2017-06-16
Publication date: 2018-12-20

Abstract

In the present invention, a pair of distance sensors 23, 24 are used to measure the distances between a table 10 and a crosshead 13 at areas near the ends of the crosshead 13. If the difference between the distances between the table 10 and crosshead 13 at the ends of the crosshead 13 is greater than or equal to a preset value, a degree of parallelism is adjusted through the driving of a motor 21 or motor 22 so as to turn a screw rod 11 or screw rod 12 until the crosshead 13 is oriented so as to be parallel to the surface of the table 10.

Description

Material testing machine

This invention relates to a material testing machine equipped with a crosshead that moves along these screw rods by the rotation of a pair of screw rods.

Such a material testing machine has a table, a pair of left and right screw rods erected rotatably on the table, and a nut portion screwed with the pair of left and right screw rods. And a cross head that moves up and down. In a material testing machine that performs a tensile test, an upper gripping tool is attached to the crosshead. In addition, a lower grip is attached to the table. The test piece is gripped at both ends by these upper and lower grips. When performing a material test, the crosshead is raised in this state. At this time, the test force applied to the test piece is detected by a load cell connected to the upper gripping tool. Further, the displacement amount between the upper and lower gauge points of the test piece is detected by a displacement meter.

In a material testing machine that performs a compression test, a platen is provided on the crosshead, and the test is performed by lowering the crosshead and pressing the platen against a test piece placed on the table. .

Patent Document 1 discloses a distance detection means for detecting a distance to a top surface of a test machine structure, such as a cross yoke, which is disposed opposite to a cross head by a reflected wave reflected from the top surface of a jig such as a load cell. When the distance obtained from the detection signal from the distance detection means reaches the reference value, the crosshead is stopped to change the attachment position of the distance detection means or correct the collision limit value. There is disclosed a material testing machine that can prevent a jig provided on a cross head from colliding with a testing machine structure such as a cross yoke without any special operation.

Further, in Patent Document 2, the length of the test piece is measured by the full length measuring unit, and based on the length of the test piece measured by the full length measuring unit, the distance between the grips using the detection rod and the position detection sensor is described. An automatic material testing machine is disclosed in which the distance between the grips can be automatically adjusted according to the length of the test piece by adjusting the distance of the test piece.

JP-A-4-166671 Japanese Patent Laid-Open No. 5-273101

In such a material testing machine, it is necessary to move up and down in a state where the crosshead is arranged in parallel to the surface of the table. Material test data made with the crosshead and table surface not parallel are not guaranteed. On the other hand, when a material test is repeatedly performed for a long time with such a material testing machine, the accuracy of parallelism between the cross head and the surface of the table is lowered.

Therefore, by measuring the parallelism between the crosshead and the table surface using a dial gauge or the like at regular intervals, and adjusting the position of the crosshead as necessary, the crosshead and table surface Therefore, the complicated work of ensuring the parallelism is required.

The present invention has been made to solve the above-mentioned problems. The parallelism between the crosshead and the table can be easily confirmed, and the parallelism between the table and the crosshead can be easily determined as necessary. An object is to provide a material testing machine that can be adjusted.

The invention according to claim 1 has a table, a pair of screw rods, and a pair of nut portions that are respectively screwed with the pair of screw rods, and the pair of screws according to the rotation of the pair of screw rods. A material testing machine comprising a crosshead that moves along a ridge, comprising a pair of measuring devices that measure the distance between the table and the crosshead at two positions separated from each other. To do.

According to a second aspect of the present invention, in the material testing machine according to the first aspect, the two positions are regions in the vicinity of both end portions of the crosshead.

The invention according to claim 3 is the material testing machine according to claim 1 or 2, further comprising a pair of motors for individually rotating the pair of screw rods, and the measurement by the pair of measuring devices. The parallelism between the table and the crosshead is adjusted by driving one of the pair of motors based on the difference in distance between the table and the crosshead.

According to a fourth aspect of the present invention, in the material testing machine according to the first or second aspect, the motor, a drive transmission mechanism that transmits the drive of the motor to the pair of screw rods, and the drive transmission mechanism. A clutch for releasing transmission of driving between one of the pair of screw rods and the motor, and a distance between the table and the crosshead measured by the pair of measuring devices. Based on the difference, the table and the table are driven by driving the motor in a state where the transmission of the drive between one of the pair of screw rods by the drive transmission mechanism and the motor is released by the clutch based on the difference. Adjust the parallelism with the crosshead.

According to the first and second aspects of the present invention, the parallelism between the crosshead and the table is obtained by measuring the distance between the table and the crosshead at two positions separated from each other with a pair of measuring instruments. Measurement can be easily performed. For this reason, the troublesome operation | work which measures the parallelism of a crosshead and a table using a dial gauge etc. conventionally becomes unnecessary.

According to the third aspect of the present invention, by driving one of the pair of motors based on the difference in the distance between the table and the crosshead measured by the pair of measuring devices, the table and the crosshead are parallel to each other. The degree can be adjusted.

According to the fourth aspect of the present invention, one of the screw rods of the pair of screw rods by the drive transmission mechanism by the clutch based on the difference in distance between the table and the cross head measured by the pair of measuring devices and the motor The parallelism between the table and the cross head can be adjusted by driving the motor in a state where the transmission of the drive between the table and the head is released.

1 is a schematic diagram of a material testing machine according to a first embodiment of the present invention. It is a block diagram which shows the main control systems of the material testing machine which concerns on 1st Embodiment of this invention. It is a schematic diagram of the material testing machine which concerns on 2nd Embodiment of this invention. It is a schematic diagram of the material testing machine which concerns on 3rd Embodiment of this invention. It is a block diagram which shows the main control systems of the material testing machine which concerns on 3rd Embodiment of this invention. It is a front view showing the neighborhood of one end of crosshead 13 in the material testing machine concerning a 4th embodiment of this invention. It is a top view which shows one end vicinity of the crosshead 13 in the material testing machine which concerns on 4th Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram of a material testing machine according to a first embodiment of the present invention.

This material testing machine has a table 10, a pair of left and

right screw rods

11 and 12 that are rotatably provided on the table 10, and a nut portion 18 that is screwed into the pair of left and

right screw rods

11 and 12. And a cross head 13 that moves up and down with respect to the

screw rods

11 and 12. An upper grip 14 is attached to the cross head 13. Further, a lower grip 15 is attached to the table 10. Both ends of the test piece 100 are gripped by the upper grip 14 and the lower grip 15.

A worm wheel 31 is fixed to the lower end of one screw rod 11. The worm wheel 31 is screwed with a worm gear (not shown) that rotates by driving the servo motor 21. A worm wheel 32 is fixed to the lower end of the other screw rod 12. The worm wheel 32 is screwed into a worm gear (not shown) that rotates by driving of the servo motor 22. By driving the servo motor 21 and the servo motor 22 synchronously, the pair of

screw rods

11 and 12 rotate synchronously. As the pair of

screw rods

11 and 12 rotate, the cross head 13 moves in the axial direction of the pair of

screw rods

11 and 12.

When carrying out a tensile test using this material testing machine, both ends of the test piece 100 are gripped by the upper grip 14 and the lower grip 15. Then, the crosshead 13 is raised. At this time, the test force applied to the test piece 100 is detected by the load cell 16 connected to the upper gripping tool 14. Further, the displacement amount between the upper and lower gauge points of the test piece 100 is detected by the displacement meter 17. Signals from the load cell 16 and the displacement meter 17 are input to the control unit 50 described later.

A pair of

distance sensors

23 and 24 are disposed on the upper surface of the table 10. These

distance sensors

23 and 24 function as a measuring instrument that measures the distance between the table 10 and the crosshead 13 in a region near both ends of the crosshead 13. The

distance sensors

23 and 24 receive light reflected from the surface of the measurement object by a light receiving element, and receive a distance from the light received by the light receiving element to the measurement object. It is a measuring instrument to calculate. As the

distance sensors

23 and 24, for example, PSD (Optical Position Sensor / Positive Sensitive Detector) or C-MOS (Complementary Metal Oxide Semiconductor) is used as the light receiving element to change the imaging position of the light receiving element due to the distance change. A triangulation type that converts, or a time-of-flight type that measures a small amount of time from when light is irradiated until it is received and converts the time difference into distance is used.

FIG. 2 is a block diagram showing a main control system of the material testing machine according to the first embodiment of the present invention.

This material testing machine includes a CPU as a processor that executes logical operations, a ROM that stores operation programs necessary for controlling the apparatus, a RAM that temporarily stores data during control, and a hard disk that stores various types of information. The control part 50 comprised from these is provided. The control unit 50 is connected to the

distance sensors

23 and 24, the

servo motors

21 and 22, the load cell 16, and the displacement meter 17 described above. Further, the control unit 50 has a function of a CPU as a processor, a distance difference calculation unit 51 that calculates a difference in distance between the table 10 and the crosshead 13 based on signals from the pair of

distance sensors

23 and 24, The parallelism between the table 10 and the crosshead 13 is driven by driving one of the pair of

servo motors

21 and 22 based on the distance difference calculated by the distance difference calculation unit 51 by the function of the CPU as a processor. A parallelism adjustment unit 52 for adjustment.

In the material testing machine having the above-described configuration, it is necessary to move up and down in a state where the crosshead 13 is arranged in parallel to the surface of the table 10. Material test data made in a state where the crosshead 13 and the surface of the table 10 are not parallel are not guaranteed. On the other hand, when a material test is repeatedly performed for a long time with such a material testing machine, the parallelism accuracy between the crosshead 13 and the surface of the table 10 is lowered.

For this reason, in the material testing machine according to the present invention, the distance between the table 10 and the crosshead 13 is periodically measured in a region near both ends of the crosshead 13 by the pair of

distance sensors

23 and 24. The measurement result is transmitted to the control unit 50. Then, the distance difference calculation unit 51 calculates the difference between the distance between the table 10 and the crosshead 13 measured by the distance sensor 23 and the distance between the table 10 and the crosshead 13 measured by the distance sensor 24. The calculation result is displayed on a display unit (not shown). Thereby, the parallelism between the cross head 13 and the table 10 can be easily measured. For this reason, unlike the prior art, the complicated work of measuring the parallelism between the crosshead 13 and the table 10 using a dial gauge or the like is not required.

This distance difference measurement may be performed periodically. For example, the distance difference may be measured every time one material test is executed, or the distance difference may be measured at the start of a day's work.

If the distance difference calculated by the distance difference calculation unit 51 is greater than or equal to a preset value, the parallelism is continuously adjusted. At this time, based on the distance difference calculated by the distance difference calculation unit 51, the parallelism adjustment unit 52 sets the cross head 13 in parallel with the surface of the table 10 so that the screw rod 11 or It is calculated how much one of the screw rods 12 should be rotated. Then, based on the calculation result, the control unit 50 drives either the servo motor 21 or the servo motor 22, and either the screw rod 11 or the screw rod 12 is placed on the surface of the table 10. On the other hand, the parallelism is adjusted by rotating it until it is arranged in parallel. Thereafter, the material test is executed in a state after the parallelism is adjusted.

Next, another embodiment of the present invention will be described. FIG. 3 is a schematic diagram of a material testing machine according to the second embodiment of the present invention. In addition, about the member similar to 1st Embodiment mentioned above, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted.

In the material testing machine according to the second embodiment, instead of the

distance sensors

23 and 24 in the material testing machine according to the first embodiment, a pair attached so that a straight line connecting them is parallel to the lower surface of the table 10. The measuring device for measuring the distance between the table 10 and the crosshead 13 in a region near both ends of the crosshead 13 is configured using the

potentiometers

33 and 34 and the cable body 37.

材料 In this material testing machine, a potentiometer 33 is disposed at one end of the crosshead 13 and a potentiometer 34 is disposed at the other end. And it has the structure which connected each

potentiometer

33,34 and the table 10 by the cable bodies 37, such as a wire. The cable body 37 is arranged in a state perpendicular to the table 10 in a state where the

potentiometers

33 and 34 and the table 10 are connected.

The

potentiometers

33 and 34 are capable of multiple rotations, and a pulley is attached to the rotation shaft of each of the

potentiometers

33 and 34, and a cable body 37 is wound around the pulley. A rotating force is applied to the shafts of the

potentiometers

33 and 34 in the direction in which the cord body 37 is tensioned by a spring or the like. Accordingly, the rotary shafts of the

potentiometers

33 and 34 rotate in conjunction with the raising and lowering of the cross head 13, so that the position of the cross head 13 can be detected from the outputs of the

potentiometers

33 and 34. Further, instead of the

potentiometers

33 and 34, a rotary encoder may be used. The main control system of the material testing machine has a configuration in which the

distance sensors

23 and 24 in FIG. 2 are changed to

potentiometers

33 and 34.

Also in the material testing machine according to the second embodiment, the distance between the table 10 and the crosshead 13 is measured in a region near the both ends of the crosshead 13 by the pair of

potentiometers

33 and 34, so that the above-described first test is performed. It is possible to easily measure the parallelism between the crosshead 13 and the table 10 and execute the adjustment by the same operation as that of the first embodiment.

Next, still another embodiment of the present invention will be described. FIG. 4 is a schematic diagram of a material testing machine according to a third embodiment of the present invention. In addition, about the member similar to 1st Embodiment shown in FIG. 1, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted.

In the material testing machine according to the third embodiment, the worm wheel 31 is fixed to the lower end portion of one screw rod 11, and the worm wheel 32 is fixed to the lower end portion of the other screw rod 12. ing. A drive shaft 30 having worm gears (not shown) threadedly engaged with the

worm wheels

31 and 32 at both ends thereof is disposed so as to be rotatable about a horizontal axis. A synchronous pulley 36 is disposed on the rotation shaft of the servo motor 22. A synchronous pulley 35 is disposed on the drive shaft 30, and a synchronous belt 38 is wound around the synchronous pulley 36 and the synchronous pulley 35.

Between the screw rod 11 of the pair of

screw rods

11 and 12 and the servo motor 22, more specifically, between the synchronous pulley 35 and the one worm wheel 31 of the drive shaft 30, A clutch 39 for releasing transmission of drive from the motor 22 to the screw rod 11 is provided. The clutch 39 switches between a transmission state in which the driving force is transmitted from one of the two shafts to the other and a transmission release state in which the transmission of the driving force is released. For this reason, when the clutch 39 is in the transmission state, when the drive shaft 30 is rotated by the drive of the servo motor 22, the pair of

screw rods

11 and 12 are rotated in synchronization. On the other hand, when the clutch 39 is in the transmission release state, when the drive shaft 30 is rotated by the drive of the servo motor 22, only the screw rod 12 is rotated.

FIG. 5 is a block diagram showing a main control system of the material testing machine according to the third embodiment of the present invention. The same members as those in the first embodiment shown in FIG. 2 are denoted by the same reference numerals, and detailed description thereof is omitted.

The control unit 50 of the material testing machine in the third embodiment is also connected to the clutch 39 described above.

Also in the material testing machine in the third embodiment, when the distance difference calculated by the distance difference calculation unit 51 is equal to or larger than a preset value, the parallelism is continuously adjusted. At this time, based on the distance difference calculated by the distance difference calculation unit 51, the parallelism adjustment unit 52 causes the screw rod 12 to be placed in a state where the crosshead 13 is arranged in parallel to the surface of the table 10. The amount of rotation is calculated. Then, based on the calculation result, the controller 50 drives the servo motor 22 with the clutch 39 in the disengaged state, and causes the screw rod 12 to be parallel to the surface of the table 10. The parallelism is adjusted by rotating it until it is placed. After that, the material test is executed in a state after the clutch 39 is in the transmission state and the parallelism is adjusted.

Next, still another embodiment of the present invention will be described. FIG. 6 is a front view showing the vicinity of one end of the crosshead 13 in the material testing machine according to the fourth embodiment of the present invention. FIG. 7 is a plan view showing the vicinity of one end of the crosshead 13 in the material testing machine according to the fourth embodiment of the present invention.

In the above-described first, second, and third embodiments, the configuration in which the distance between the crosshead 13 and the table 10 is directly measured by the

distance sensors

23 and 24 or the

potentiometers

33 and 34 is employed. On the other hand, in this 4th Embodiment, the structure which measures the distance of the crosshead 13 and the table 10 by measuring the height position of the crosshead 13 is employ | adopted.

In the material testing machine according to the fourth embodiment, the dog 26 for the proximity sensor 25 is disposed at the end of the crosshead 13. The dogs 26 are disposed at both ends of the cross head 13 and are used to detect the height positions of the both ends. The dog 26 is fixed at a position having a predetermined height from the table 10. In this embodiment, the parallelism between the cross head 13 and the table 10 is separately measured, and the positions of the dogs 26 detected by the proximity sensor 25 are recorded in a state in which they are in parallel. Based on the 25 signals, the parallelism between the cross head 13 and the table 10 can be confirmed.

More specifically, since the distance between the proximity sensor 25 and the table 10 is known in advance, by detecting the positions of both ends of the crosshead 13 when the dog 26 is detected by the pair of proximity sensors 25, The distance between the dog 26 fixed to one end of the cross head 13 and the table 10 can be obtained. Assuming that the dog 26 and the proximity sensor 25 are correctly attached, when the crosshead 13 and the table 10 are parallel, the outputs of the two proximity sensors 25 disposed at both ends of the crosshead 13 are used. The timing of is simultaneous. Since the output timing of the proximity sensor 25 disposed at both ends of the crosshead 13 is shifted when the parallelism is shifted, the shift amount is calculated based on the moving speed of the crosshead 13, so that the output at the both ends of the crosshead 13 is calculated. The distance difference from the table 10 can be calculated. In addition, since the attachment positions of the dog 26 and the proximity sensor 25 at both ends of the crosshead 13 often include an error, even if the crosshead 13 and the table 10 are correctly parallel, the proximity sensor 25 is not necessarily at the same time. It doesn't work. In this case, this difference may be measured and stored in advance. That is, the parallelism between the crosshead 13 and the table 10 is separately measured, and the detection position of the dog 26 by the proximity sensor 25 when the parallelism accuracy is sufficiently obtained is recorded, so that it is based on the value of the proximity sensor 25. Thus, the parallelism adjustment can be confirmed.

In any of the above-described embodiments, the present invention is applied to a material testing machine that holds both ends of the test piece 100 with the upper gripping tool 14 and the lower gripping tool 15 and performs a tensile test on the test piece 100. However, the present invention may be applied to a material testing machine that places a platen on the crosshead 13 and performs a compression test on a test piece placed on a table.

10 Table 11 Screw rod 12 Screw rod 13 Crosshead 14 Upper grip 15 Lower grip 16 Load cell 17 Displacement meter 18 Nut 21 Servo motor 22 Servo motor 23 Distance sensor 24 Distance sensor 25 Proximity sensor 26 Dog 33 Potentiometer 34 Potentiometer 37 Cable Body 39 Clutch 50 Control part 51 Distance difference calculation part 52 Parallelism adjustment part 100 Test piece

Claims

A crosshead having a table, a pair of screw rods, and a pair of nut portions that are screwed together with the pair of screw rods, and moving along the pair of screw rods as the pair of screw rods rotate. In a material testing machine equipped with
A material testing machine comprising a pair of measuring devices for measuring the distance between the table and the crosshead at two positions separated from each other.
The material testing machine according to claim 1,
The material testing machine, wherein the two positions are regions near both ends of the crosshead.
In the material testing machine according to claim 1 or 2,
A pair of motors for individually rotating the pair of screw rods;
A material that adjusts the parallelism between the table and the crosshead by driving one of the pair of motors based on a difference in distance between the table and the crosshead measured by the pair of measuring devices. testing machine.
In the material testing machine according to claim 1 or 2,
A motor,
A drive transmission mechanism for transmitting the drive of the motor to the pair of screw rods;
A clutch for releasing transmission of drive between one of the pair of screw rods by the drive transmission mechanism and the motor;
Based on a difference in distance between the table and the cross head measured by the pair of measuring devices, a clutch is used to drive between one screw rod of the pair of screw rods and the motor by the drive transmission mechanism. A material testing machine that adjusts the parallelism between the table and the crosshead by driving the motor in a state where the transmission is released.