JP5494379B2 - Material testing machine - Google Patents

Description

  The present invention relates to a material testing machine that applies a test force to a test piece by rotating a pair of screw rods synchronously by a servo motor.

  In such a material testing machine, both ends of the crosshead are engaged with a screw rod through nuts, and the crosshead is moved up and down by the rotation of the screw rod. A test piece for testing the tensile strength or the like of a test piece by applying a tensile load or the like to a test piece held at both ends of the attached chuck is used. The test force applied to the test piece is measured by a load cell, and the displacement of the test piece is measured by a displacement meter.

  By the way, when performing a relatively simple material test, such as when performing the above-described tensile test, or when performing a compression test by applying a compressive force to a test piece, the jig is determined from the actual test time itself. In many cases, the preparation process such as replacement of the test piece or test piece takes time. For this reason, Patent Document 1 discloses that a motor for driving a pump of a hydraulic unit that supplies hydraulic oil to a hydraulic actuator has a variable number of revolutions, and the number of revolutions of the motor is tested from a test preparation of a material testing machine. By automatically changing according to each state until the end, it is possible to reduce the power consumption by rotating at a low speed when the hydraulic oil flow rate is not required, such as during test preparation, and by rotating at a high speed only when necessary. A hydraulically driven material testing machine is disclosed.

JP 2004-163149 A

  By the way, as a material testing machine for conducting comparatively small and highly accurate material tests, an electric material test that applies a test force to a test piece by rotating a pair of screw rods synchronously with a servo motor. Machines are also frequently used. In such a material testing machine, after the power switch is turned on and the device starts up normally, the servo motor is driven unless an abnormality occurs such as the power switch is turned off or the emergency stop switch is pressed. Since electric power continues to be supplied to the servo amplifier, useless electric power is used. Even while the servo motor is not rotating, the servo amplifier continues to issue a servo lock command to hold the output shaft at that position by electromagnetic force to the servo motor. For this reason, a large amount of power is consumed even though the output shaft of the servo motor is not rotating.

  The present invention has been made to solve the above-described problem, and is a material capable of reducing power consumption by a servo amplifier or a servo motor during non-operation when a material test or an operation related to the material test is not performed. The purpose is to provide a testing machine.

The invention according to claim 1 includes a pair of screw rods, a servo motor that rotates the screw rods synchronously, and a nut portion that engages with the pair of screw rods, and the rotation of the screw rods A servo amplifier connected to the servomotor in a material testing machine comprising: a crosshead that moves along the screw rod; and a load cell that measures a change in test force applied to the test piece as the crosshead moves. A control unit that controls power supply to the servo amplifier and servo lock by the servo amplifier, and the control unit is in a non-operating state when a material test or an operation related to the material test is not performed. The servo lock by the servo amplifier is stopped when the test force measured by the load cell is equal to or less than a set value .

According to a second aspect of the present invention, in the first aspect of the invention, the control unit stops the supply of power to the servo amplifier after a set time has elapsed after the servo lock is stopped by the servo amplifier. .

According to a third aspect of the present invention, in the first or second aspect of the present invention, the material test mode for executing the material test, the return mode for returning the crosshead to a predetermined position, and the crosshead by manual operation. A manual operation mode that can be moved, and the control unit performs an operation related to a material test or a material test in a state that is not any of the material test mode, the return mode, and the manual operation mode. and that there is no non-operating at the time, to stop the Saboro' phrases by before Symbol servo amplifier.

According to the invention described in claim 1, nonworking time that operations related to the material testing or material testing is not performed, it is possible to reduce power consumption by servomotor.

In addition , since the servo lock by the servo amplifier is stopped when the test force is less than the set value, the servo lock is stopped only when the servo lock can be safely released. Can be secured.

According to the invention described in claim 2 , since the supply of power to the servo amplifier is stopped after the set time has elapsed after the servo lock is stopped by the servo amplifier, the power consumption is further reduced while ensuring safety. It becomes possible to do.

According to the third aspect of the present invention, none of the material test mode for executing the material test, the return mode for returning the crosshead to a predetermined position, and the manual operation mode for manually moving the crosshead. in the non-operating state of the apparatus, it is possible to reduce power consumption by servomotor.

1 is a schematic diagram of a material testing machine according to the present invention. It is a block diagram which shows the main electrical structures of the material testing machine which concerns on this invention. It is a flowchart which shows the electric power supply by the material testing machine which concerns on this invention, and the stop operation of a servo lock.

  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 the present invention.

  The material testing machine includes a base 16, a pair of left and right screw rods 17 erected on the base 16, and a nut portion screwed with the pair of left and right screw rods 17. And a cross head 23 that moves up and down. An upper grip 11 is attached to the cross head 23 via an axis adjusting device 20 and a load cell 13. A lower grip 12 is attached to the base 16. The both ends of the test piece 10 are gripped by the upper grip 11 and the lower grip 12.

  Synchronous pulleys 21 that engage with the synchronous belt 22 are disposed at the lower ends of the pair of screw rods 17, respectively. The synchronous belt 22 is also engaged with a synchronous pulley 19 that rotates by driving of the servo motor 18. For this reason, the pair of screw rods 17 rotate in synchronization with the drive of the servo motor 18. Then, as the pair of screw rods 17 rotate in synchronization, the cross head 23 moves up and down in the axial direction of the pair of screw rods 17.

  The test force applied to the test piece 10 is detected by the load cell 13. Further, the displacement amount between the upper and lower gauge points of the test piece 10 is detected by the displacement meter 14. Signals from the load cell 13 and the displacement meter 14 are input to a control unit 40 described later. The control unit 40 creates a drive control signal for the servo motor 18 based on signals from the load cell 15 and the displacement meter 14. Thereby, the rotation of the servo motor 18 is controlled, and various material tests such as tension and compression are performed.

  FIG. 2 is a block diagram showing the main electrical configuration of the material testing machine according to the present invention.

  This material testing machine includes a servo amplifier 33 that drives and controls the servo motor 18 described above. Electric power is supplied to the servo amplifier 33 from the main power supply via the electromagnetic contactor 31 that is turned on / off by the drive relay 32. The drive relay 32 turns the electromagnetic contactor 31 on and off with a signal from the microcomputer 34 controlled by the control unit 40. When the emergency stop switch 35 is pressed or when the crosshead 23 moves to the end and the limit switch 36 is pressed, the drive relay 32 turns off the electromagnetic contactor 31. Further, the microcomputer 34 transmits a servo lock on / off signal from the servo amplifier 33 to the servo amplifier 33 based on a control signal from the control unit 40.

  The control unit 40 is connected to the load cell 13 and the displacement meter 14 shown in FIG. The control unit 40 is connected to a start button 41 for starting a material test and a return button 42 for returning the crosshead 23 to a predetermined position. Further, the control unit 40 is also connected to a display unit 43 such as a monitor and an input unit 44 such as a keyboard.

  Next, power supply and servo lock stop operation by the material testing machine according to the present invention will be described. FIG. 3 is a flowchart showing a power supply and servo lock stop operation by the material testing machine according to the present invention.

  When power supply and servo lock stop operation are performed, steps S2 to S7 shown in FIG. 3 are executed. However, when the material testing machine is in any of the material test mode, return mode, and manual operation mode, which will be described later, it is determined that the apparatus is in operation (step S1), and the process always returns to step S2.

  When performing the power supply and servo lock stop operation, first, the control unit 40 confirms whether or not the apparatus is in the material test mode (step S2). Here, the material test mode is a mode in which a material test is actually executed. This material test mode starts when the start button 41 is pressed. When the material test is being performed, the power supply and the servo lock stop operation cannot be executed, so that the end of the material test mode is awaited.

  If the apparatus is not in the material test mode, the control unit 40 next checks whether or not the apparatus is in the return mode (step S3). Here, the return mode is a mode in which the crosshead 23 is returned to the origin position or the like after the material test. This return mode starts when the return button 42 is pressed. Even during the movement of the crosshead 23, the power supply and the servo lock stop operation cannot be executed, so the end of the return mode is awaited.

  If the apparatus is not in the return mode, the control unit 40 next checks whether or not the apparatus is in the manual operation mode (step S4). Here, the manual operation mode means that the operator moves the crosshead 23 by a manual operation by the operator by performing a predetermined setting using the input unit 44 or by operating an operation button or the like. This is a possible mode. Even in the manual operation mode, it is not preferable to execute the operation of stopping the power supply and servo lock, so the end of the manual operation mode is awaited.

  When the apparatus is in a non-operating state that is neither a material test mode for executing a material test, a return mode for returning the crosshead 23 to a predetermined position, or a manual operation mode for manually moving the crosshead 23 Next, it is determined whether or not the test force measured by the load cell 13 by the control unit 40 is equal to or less than a set value (step S5).

  That is, when the servo lock is stopped in a state where a predetermined test force is applied to the test piece 10, there is a risk that the crosshead 23 is moved by the test force even if the servo motor 18 is stopped. For this reason, the servo lock is stopped only when the test force is below the set value. The set value of the test force at this time is a value obtained in advance by an experiment or the like as a test force in which the crosshead 23 does not move even when the servo lock is stopped. As this set value, for example, a value of about 5% of the frame capacity that is the maximum allowable load of the load frame constituted by the screw rod 17 and the cross head 23 can be applied.

  If the test force measured by the load cell 13 at that time is equal to or less than the set value, the control unit 40 issues a command to the servo amplifier 33 via the microcomputer 34 and stops the servo lock (step S6). Thereby, it is possible to prevent waste of electric power used in the servo lock for holding the output shaft of the servo motor 18 at the position by the electromagnetic force. At this time, the display unit 43 may be turned off to further save power.

  For example, when a time of about 20 minutes elapses after the servo lock is stopped (step S7), the control unit 40 issues a command to the drive relay 32 via the microcomputer 34 to turn off the electromagnetic contactor 31. As a result, the supply of power to the servo amplifier 33 is stopped. Thereby, further power saving can be achieved.

  Even when the servo lock is stopped or the power supply to the servo amplifier 33 is stopped, the start button 41, the return button 42, etc. are operated, and the material testing machine operates the material test mode, return mode, manual described later. When one of the operation modes is entered, the process always returns to step S2.

  In the above-described embodiment, the power supply to the servo amplifier 33 is stopped after the servo lock by the servo amplifier 33 is released when not in operation. However, the present invention is limited to such a form. is not. In the above-described embodiment, both the power supply to the servo amplifier 33 and the servo lock by the servo amplifier 33 are stopped when not in operation. However, the power supply to the servo amplifier 33 or the servo by the servo amplifier 33 is stopped. Only one of the locks may be stopped.

DESCRIPTION OF SYMBOLS 10 Test piece 11 Upper grip 12 Lower grip 13 Load cell 14 Displacement meter 17 Screw rod 18 Servo motor 20 Axis center adjustment device 23 Cross head 31 Electromagnetic contactor 32 Drive relay 33 Servo amplifier 34 Microcomputer 40 Control part 41 Start button 42 Return Button 43 Display 44 Input

Claims (3)

A pair of screw rods, a servo motor that rotates the screw rods synchronously, and a nut portion that engages with the pair of screw rods, and moves along the screw rods as the screw rods rotate. In a material testing machine comprising: a crosshead; and a load cell that measures a change in test force with respect to a test piece as the crosshead moves.
A servo amplifier connected to the servo motor;
A controller that controls power supply to the servo amplifier and servo lock by the servo amplifier;
The control unit is a material testing machine that stops the servo lock by the servo amplifier when the test force measured by the load cell is equal to or less than a set value when the material test or the operation related to the material test is not performed. . The material testing machine according to claim 1 ,
The control unit is a material testing machine that stops the supply of power to the servo amplifier after a set time has elapsed after stopping the servo lock by the servo amplifier. In the material testing machine according to claim 1 or 2 ,
It has a material test mode for executing a material test, a return mode for returning the crosshead to a predetermined position, and a manual operation mode for manually moving the crosshead.
Wherein the control unit, the material testing mode, the return mode, in a state neither of the manual operation mode, non-working sometimes operations associated with material testing or material testing is not running, Saboro' by pre Symbol servo amplifier Material testing machine that stops

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