JP2007017315A - Viscoelasticity measuring method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a viscoelasticity measuring method which achieves an enhancement of measuring precision. <P>SOLUTION: The torque at the time of application of reciprocating rotatory power to a die 12 by a rotary mechanism part 16 is detected using a viscoelasticity measuring instrument, which is equipped with upper and lower dies 10 and 12 in which a testpiece A is inserted, the heater 14 arranged on the outer periphery of the dies, the rotary mechanism part 16 for applying rotary power to the die 12 and a torque detecting part 18 for detecting the torque transmitted to the upper die 10 while heating the testpiece A to measure a change in the hardness of the testpiece A with the elapse of time from the detected value. At this time, a torsion spring like correction block body capable of neglecting loss torque is inserted in the dies 10 and 12 in place of the testpiece to set mechanical zero position timing becoming zero in the torque detection value. Thereafter, the correction block body is replaced with the testpiece to perform measurement. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a viscoelasticity measuring method, and more particularly to a technique for improving the accuracy of measured values.

  Conventionally, for example, devices disclosed in Patent Documents 1 and 2 are known as viscoelasticity measuring devices capable of tracking the curing process of unvulcanized rubber and thermosetting resin. The viscoelasticity measuring devices disclosed in these patent documents are configured to be separable in the vertical direction, and upper and lower dies into which test pieces are inserted, and heating heaters disposed on the outer periphery of these dies. When a reciprocating rotational force is applied to the lower die while heating the test piece with the heater, the torque transmitted to the upper die through the test piece is detected and the degree of hardening of the test piece is changed. It is the basic structure of the measurement to obtain this over time.

  In this case, the reciprocating rotational force of the lower die is generally applied by an electric motor, and a load cell is usually used for torque detection. The rotational force of the electric motor is applied so as to be reversed and reciprocated at every predetermined rotational angle. In this case, it is desirable that the rotational speed be constant. From this point of view, conventionally, this type of measuring device has been used. As the motor, a single-phase synchronous motor was used.

However, the viscoelasticity measuring apparatus employing such an electric motor has technical problems described below.
Japanese Examined Patent Publication No. 3-67223 Japanese Patent Publication No.7-72710

  That is, the rotational force applied to the lower die by the electric motor is at the center position (usually called the mechanical zero position) at the start, and then needs to be reciprocated at equal angular intervals in the left-right direction. Therefore, in the conventional viscoelasticity measuring apparatus, a stop target position corresponding to the mechanical zero position is provided on the lower die, and the lower die is manually positioned at that position.

  However, since it is difficult to control the synchronous motor to stop at a required position, the above-described positioning takes time, and it is also difficult to accurately position, resulting in a decrease in measurement accuracy. was there.

  The present invention has been made in view of such conventional problems, and an object of the present invention is to provide a viscoelasticity measuring method capable of accurately positioning a lower die for applying a rotational force. There is.

  In order to achieve the above object, the present invention is configured to be separable in the vertical direction, upper and lower dies into which test pieces are inserted, heaters for heating disposed on the outer periphery of these dies, Using a viscoelasticity measuring device comprising a rotation mechanism that applies a rotational force to the lower die and a torque detector that detects torque transmitted to the upper die via the test piece, the test piece is heated by a heater. However, when the reciprocating rotational force is applied to the lower die by the rotation mechanism unit, the torque is detected by the torque detection unit, and the degree of hardening of the test piece over time is detected from the detected value of the torque detection unit. In the viscoelasticity measuring method for measuring the change of the test piece, before measuring the test piece, the loss when the torque is transmitted to the upper die instead of the test piece between the upper and lower dies. Torsion spring with negligible torque The calibration block body is inserted and set to the mechanical zero position timing at which the detected value of the torque detection unit becomes 0 value. After that, the calibration block body is replaced with the test piece to perform measurement. I made it.

  According to the viscoelasticity measuring method configured as described above, a torsion spring-like calibration block that can ignore the torque loss when torque is transmitted to the upper die, instead of the test piece, between the upper and lower dies. Insert the body, set the mechanical zero position timing at which the detection value of the torque detector becomes 0 value, and then replace the calibration block body with the test piece and perform the measurement, so the mechanical zero position is accurate In the subsequent measurement of the test piece, viscoelasticity can be accurately measured.

The rotation mechanism unit may include a single-phase synchronous motor.
The synchronous motor can be stopped by applying a DC voltage after a predetermined time has elapsed after stopping the supply of the AC voltage of the motor.

  The calibration block body may be composed of upper and lower disk portions that respectively contact the upper and lower dies, and columnar portions that are fixed at both ends between the upper and lower disk portions.

  The upper and lower dies can be provided with irregularities on the contact surfaces of the test piece or the calibration block body with the upper and lower disk portions.

  According to the viscoelasticity measuring method of the present invention, the lower die for performing reciprocating rotational movement can be accurately positioned at the mechanical zero position at the time of starting, so that the measurement accuracy is improved.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings.

  1 to 10 show an embodiment of a viscoelasticity measuring method according to the present invention. The viscoelasticity measuring apparatus used in the present embodiment is, as shown in the conceptual diagram of FIG. 1, the upper and lower dies 10, 12, a heating heater 14, a rotating mechanism unit 16, a torque detecting unit 18, And a control unit 20.

  The upper and lower dies 10 and 12 are configured so as to be separable in the vertical direction and are disposed to face each other, and the test piece A is inserted therebetween. In FIG. 1, the upper and lower dies 10 and 12 are simplified and shown as flat plate shapes, but are actually configured as shown in FIG.

  The upper die 10 shown in FIG. 7 is held by a holder 11 and formed in a substantially convex shape, and the lower die 12 is also held by the holder 13 in the same manner. As shown in FIG. 4, the opposing flat surfaces of the dies 10 and 12 are provided with mesh-like irregularities 15 to prevent slippage between the test piece A and the calibration block body B with which they contact. It has a structure.

  The heater 14 is disposed on the outer periphery of the upper and lower dies 10, 12 so as to surround the outer periphery of the dies 10, 12, and heats the test piece A to a predetermined temperature. The rotation mechanism unit 16 applies a rotational force to the lower die 12, and in the case of this embodiment, as shown in FIG. 3, a single-phase synchronous motor 16a, a timing belt 16b, a cone drive And a mechanism 16c.

  One end side of the cone drive mechanism 16c is connected to the rotating shaft of the synchronous motor 16a through the timing belt 16b, and the other end side is connected to the center of the lower surface side of the lower die 12 through the vertical shaft 16e.

  In the rotation mechanism section 16 configured as described above, when a single-phase AC power is supplied to the synchronous motor 16a and driven, the one end side of the cone drive mechanism 16c rotates, and the other end side is a vertical axis. As a result, the lower die 12 moves around the vertical axis (rotation center 0), for example, within a range of about 1 ° in the left-right direction as shown in FIG. While reversing, it reciprocates.

  Note that reference numeral 16d in FIG. 1 denotes a ΦA timing detection unit that detects the switching timing of the rotation direction of the cone drive mechanism 16c, and as shown in FIGS.

  As shown in FIG. 2, the torque detection unit 18 includes a load cell 18a, an amplifier 18b, and a torque transmission unit 18c provided between the upper end of the upper die 10 and the load cell 18a. Thus, the torque transmitted to the upper die 10 via the test piece A is detected.

  The control unit 20 includes a controller 20a and a monitor 20b. The controller 20a includes the motor control circuit 20c shown in FIG. 5, and also receives output signals from the ΦA timing detector 16d and the amplifier 18b, and displays these signal waveforms on the monitor 20b. Let

  Further, a control signal is sent from the controller 20a to the heater 14 for heating, the heating temperature when the test piece A is heated is also taken in, and the heating state of the test piece A is also controlled.

  As shown in FIG. 5, the motor control circuit 20c includes a commercial power source 200c, a DC power source 201c, a sequencer 202c, a changeover switch 203c, a relay 204c, a start SW, and a stop SW.

  The changeover switch 203c is connected to the synchronous motor 16a on one end side, and can be connected to the commercial power supply 200c and the DC power supply 201c on the other end side. Switching of these power supplies is performed by turning on and off the relay 204c. Is called.

  The control signal of the relay 204c is sent out by the sequencer 202c. When the synchronous motor 16a is driven to rotate, the commercial power source 200c is connected to the changeover switch 203c, and when the synchronous motor 16a is stopped, the DC power source 201c is switched. Connected to the switch 203c.

  In the viscoelasticity measuring apparatus configured as described above, when measuring the change in the degree of cure over time relative to the degree of vulcanization of the test piece A, for example, rubber, while heating the test piece A with the heater 14, The torque when the reciprocating rotational force is applied to the lower die 12 by the rotation mechanism unit 16 is detected by the load cell 18a of the torque detection unit 18, and the degree of cure is measured from the detected value of the load cell 18a.

  In the case of this example, as shown in detail in FIG. 6, the test piece A is a disk having a thickness of 3 mm and a major axis of 30 mm.

  The basics of such a measurement method are the same as those of this type of conventional viscoelasticity measurement method, but the present embodiment has remarkable features in the following points. That is, in the case of the present embodiment, before measuring the test piece A, the calibration block body B is inserted between the upper and lower dies 10 and 12 instead of the test piece A.

  The calibration block body B has a torsion spring property in which a loss of torque transmitted to the upper die 10 can be ignored when a reciprocating rotational force is applied to the lower die 12. The calibration block body B is inserted between the dies 10 and 11 and set to the mechanical zero position timing at which the detection value of the torque detector 18 becomes 0. Thereafter, the calibration block body B is replaced with the test piece A. Measurement will be performed.

  FIG. 7 shows a state in which the calibration block body B is inserted between the upper die 10 and the lower die 12. In the case of the present embodiment, the calibration block body B has both ends between the upper disk portion B1 that contacts the upper die 10, the lower disk portion B2 that contacts the lower die 12, and the upper and lower disk portions B1 and B2. It is comprised from the columnar part B3 to which it adhered.

  The calibration block body B having such a shape is made of, for example, phosphor bronze, and the torque transmitted to the upper die 10 when the length of the columnar portion B3 is 90 mm and the diameter is 9 mm. The torsion spring property is negligible.

  The calibration block body B having such properties is used for the following reason. That is, when the shape of the test piece A shown in FIG. 6 is rubber and the material is rubber, as shown in FIG. 6B, the torque as a reaction force when rotating by 1 ° is about 0.05 Nm. . On the other hand, when the specimen A has the same shape and is made of phosphor bronze, a similar torque is 20000 Nm, and if the magnitude of such a torque is measured by the detector 18, a very large torque is required. become.

  Therefore, in this embodiment, the calibration block body B having the shape shown in FIG. 7 is adopted, and the torque required to rotate the angle by 1 ° is set to about 4.5 Nm as a practical value. This torque is set to about 4 to 5 times that of a standard rubber because the maximum torque during vulcanization is about 1 Nm.

  The measurement method as described above is used for the following reason. That is, the rotational force applied to the lower die 12 by the synchronous motor 16a is at the mechanical zero position (0 position which is the center of the vertical shaft 16e shown in FIG. 3) at the start, and thereafter is equiangularly spaced in the left-right direction ( It is necessary to reciprocate at ± 1 °.

  At this time, if the stop position of the motor 16a is shifted to the + side, as shown in FIG. 8A, the detection signal of the load cell 18a is shifted upward, and the stop position of the motor 16a is − If shifted to the side, the detection signal of the load cell 18a shifts downward as shown in FIG. 8B.

  When such a phenomenon occurs, the center of the detection signal input to the load cell amplifier 18b is shifted. As a result, an excessive input is made to the amplifier 18b, and the linearity is lost, so that an accurate measurement result can be obtained. Absent.

  Therefore, in this embodiment, a method has been devised in which the stop position of the electric motor 16a is accurately at the mechanical zero position timing, and the calibration block body B in which the loss torque can be ignored is used as the upper and lower dies 10,12. When the reciprocating rotational force is inserted between them and is applied by the rotational drive unit 16, it is detected as it is by the load cell 18a. Therefore, using this fact, the stop position of the synchronous motor 16a, that is, the rotational drive is applied. It is intended to make the initial position exactly coincide with the mechanical zero position timing.

  FIG. 9 shows a case in which the detection signal of the load cell 18a and the detection signal of the ΦA detection unit 16d are displayed on the monitor 20b when the phosphor block shown in FIG. 6 is used as the calibration block body B. Since the loss torque of the calibration block body B can be ignored, it can be seen that these signals are synchronized and there is no phase difference.

  When the synchronous motor 16a is stopped in such a state, the lower die 12 can be accurately positioned at the mechanical zero position timing at the start. In this case, since the control of the stop position of the synchronous motor 16a is usually difficult, in this embodiment, a stop method of applying a DC voltage is adopted.

  In this control method, in the control circuit 20c shown in FIG. 5, after the supply of the commercial power supply 200c is stopped, the relay 204c is operated after a time of about 10 msec to 300 msec (same as the time when the exciting magnetic force disappears). In this method, the DC power supply 201c is supplied. According to this stopping method, the synchronous motor 16a can be stopped at a desired position.

  As described above, after the synchronous motor 16a is stopped at a desired position, that is, a position having no phase difference shown in FIG. 8, the test piece A is replaced with the upper and lower dice 10, instead of the calibration block body B. 12, the torque when the reciprocating rotational force is applied to the lower die 12 by the rotation mechanism unit 16 while the test piece A is heated by the heater 14 is detected by the load cell 18 a of the torque detection unit 18. The degree of cure is measured from the detected value of the load cell 18a, and the measurement result at that time is shown in FIG.

  Now, according to the viscoelasticity measuring method configured as described above, before the test piece A is measured, a screw with negligible loss torque can be substituted between the upper and lower dies 10 and 12 instead of the test piece A. A torsion spring-shaped calibration block body B is inserted and set to a mechanical zero position timing at which the detection value of the torque detector 18 becomes 0. Thereafter, the calibration block body B is replaced with a test piece A. Since the measurement is performed, the mechanical zero position is accurately set, and viscoelasticity can be accurately measured in the subsequent measurement of the test piece.

  As a result, excessive input to the load cell amplifier 18b is eliminated and linearity is ensured, so that an accurate measurement result can be obtained.

  According to the viscoelasticity measuring method of the present invention, the measurement accuracy of the degree of cure of rubber or the like is improved, and therefore it can be effectively used when vulcanizing rubber or the like.

It is a conceptual diagram which shows an example of the viscoelasticity measuring apparatus with which the measuring method concerning this invention is applied. It is A arrow directional view of FIG. It is a B arrow line view of FIG. It is a principal part detail drawing of FIG. It is a control circuit diagram of the electric motor of the measuring apparatus shown in FIG. It is detailed explanatory drawing of the test piece used with the viscoelasticity measuring apparatus of this invention. It is explanatory drawing of the state which set the calibration block body to the measuring apparatus with which the measuring method of this invention is applied. It is explanatory drawing which shows the malfunction of the conventional measuring method. It is a graph of the measurement result at the time of using a calibration block body with the measuring method concerning the present invention. It is a graph of a measurement result at the time of using a test piece with the measuring method concerning the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Upper die 12 Lower die 14 Heater 16 Rotation mechanism part 16a Synchronous motor 16b Timing belt 16c Cone drive mechanism 16d ΦA detection part 18 Torque detection part 18a Load cell 18b Load cell amplifier 20 Control part 20a Controller 20b Monitor 20c Motor control circuit

Claims (5)

Upper and lower dies configured to be separable in the vertical direction and having test pieces inserted therein, heating heaters disposed on the outer periphery of these dies, and a rotation mechanism unit that applies a rotational force to the lower dies And a viscoelasticity measuring device including a torque detection unit for detecting torque transmitted to the upper die through the test piece, while the test piece is heated by a heater, the rotating mechanism unit is attached to the lower die. In the viscoelasticity measuring method for detecting the torque when the reciprocating rotational force is applied by the torque detector, and measuring the change in the degree of curing of the test piece over time from the detection value of the torque detector,
Before measuring the test piece, instead of the test piece, the torsion spring-like calibration block in which the torque lost when the torque is transmitted to the upper die can be ignored between the upper and lower dies. Insert your body
Set the mechanical zero position timing at which the detected value of the torque detection unit becomes 0 value,
Thereafter, the viscoelasticity measuring method is characterized in that the measurement is performed by replacing the calibration block body with the test piece.   The viscoelasticity measurement method according to claim 1, wherein the rotation mechanism unit includes a single-phase synchronous motor.   3. The viscoelasticity measuring method according to claim 2, wherein the synchronous motor is stopped by applying a DC voltage after a predetermined time has elapsed after stopping the supply of the AC voltage of the motor.   2. The calibration block body includes an upper and lower disk part that respectively contacts the upper and lower dies, and a columnar part having both ends fixed between the upper and lower disk parts. The measuring method of viscoelasticity of any one of -3.   The upper and lower dies are provided with irregularities on contact surfaces of the test piece or the calibration block body with the upper and lower disk parts, respectively. Measurement method of viscoelasticity.

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