JP3262883B2 - Rubber sample calorific value measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for measuring the calorific value of a rubber sample, and more particularly to a temperature measuring device for evaluating the heat generation characteristics of a viscoelastic body represented by rubber.

[0002]

2. Description of the Related Art As a method for evaluating the calorific value of a viscoelastic body represented by rubber, generally, ASTMD-623-67M is used.
ethodA is used, and its measuring device is a Goodrich flexometer conforming to this standard (Goodrich).
Flexometers, or devices for measuring the calorific value of rubber samples, are widely used.

[0003] The structure and operation of this conventional example will be briefly described. FIG. 4 is a perspective view schematically showing an apparatus for measuring the calorific value of a rubber sample, which has been conventionally used, and shows a driving motor 1.
01, the rotational motion of the drive shaft 103 driven via the V-pull 102 is converted into a vertical motion by an eccentric wheel 104 provided on the drive shaft 103. The cylindrically shaped sample 110 is sandwiched between an upper anvil 111 and a lower anvil 112, and has a thermocouple contact 114 thermally insulated by an ebonite plate 113 at the center of the lower anvil 112. Lead wire 1 extending from
15 is connected to the temperature measuring device main body 116 and the sample 1
Ten temperatures can be recorded.

[0004] A static load and a dynamic load are applied to the sample 110, and a compressive load of the static load is applied by a balance method. The balance lever 120 of the balance is supported by a knife-edge type fulcrum 121, and balance weights 122 and 123 are suspended from both ends of the balance, respectively. On the rear balance weight 123, a load weight 124 whose weight can be adjusted is placed. When the load weight 124 is placed, the balance lever 120 is tilted, and the upper anvil adjustment screw 118 pushes the lower anvil 112 fixed so that the height can be adjusted in the vertical direction on the upper surface thereof. A compressive load is applied.

[0005] A differential transformer 125 is connected to the rear of the balance lever 120. When the balance lever 120 is tilted, the displacement amount, that is, the compression change amount of the sample 110,
The detection signal is detected by a differential transformer 125, and this detection signal is amplified by a motor control circuit (not shown), converted into the rotation amount of the reversible motor 127, and
The speed is reduced at 28 and converted into rotation of a rotation shaft extending in the longitudinal direction inside the balance lever 120 by a worm gear built in the balance lever 120 via an electromagnetic clutch 129. The rotation shaft rotates the helical gear, which rotates the anvil adjusting screw 118 to move the lower anvil 112 up and down. As a result, the balance lever 120 is controlled to be always horizontal.

After the compressive load is applied to the sample 110 in this way, the eccentric wheel 104 is rotated by the driving motor 101 to move the connecting rod 140 up and down, and the connecting rod pin 141 is connected to the connecting rod 140. Connecting rod plate 1 connected via
42 is moved up and down. Connecting rod plate 142
Is provided with an upper anvil receiver 144 via a driving rod 143.
The upper anvil 111 provided below is moved up and down by the rotation of the driving motor 101 to operate so as to repeatedly apply a compressive strain to the sample 110. The amount of displacement of the upper anvil 111, ie, the amount of deformation of the sample 110, can be read by the deformation indicator 146 via an indicator rod 145 extending upward from the upper anvil receiver 144.

[0007]

However, in the above-described conventional calorific value measuring apparatus for a rubber sample, as shown in an enlarged view of FIG. 5, a heat insulating member provided not on the center of the sample but on the lower anvil 112 is provided. Incomplete ebonite plate 11
The sample 1 is connected to a thermocouple contact 114 provided on the upper surface of the sample 1.
The temperature of the bottom surface of No. 10 was measured. For this reason, the heat generated by the sample due to the compressive strain is generated by the ebonite plate 113.
The temperature measured on the bottom surface of the sample differs from the center of the sample depending on the calorific value, the time, and the coefficient of heat conduction, but is shown to be lower by about 40 to 100 ° C.

As described above, in the conventional calorific value measuring device for a rubber sample, there is a large error in temperature measurement.
There is a problem that the calorific value due to the repetitive compression strain cannot be correctly grasped. In view of the above problems, an object of the present invention is to provide an apparatus for measuring the calorific value of a rubber sample capable of measuring the temperature at the center of the rubber sample in order to accurately grasp the calorific value in a repeated compression strain test of the rubber sample. It is to provide.

[0009]

To solve the above problems, the present invention has the following arrangement. That is, the present invention provides a method for measuring the calorific value of a rubber sample by repeatedly applying a predetermined compression strain to a rubber sample held in a sample holder while applying a predetermined compression load to measure the temperature of the rubber sample. In the device, a thermosensitive element for temperature measurement inserted into the rubber sample and a flange portion for projecting a temperature measuring point of the thermosensitive element by a length equal to a length from a side surface to a center of the rubber sample at a tip. A thermosensitive element lead wire sheath having a slider fixed at a position of the thermosensitive element lead wire sheath separated by a certain distance from a temperature measurement point of the thermosensitive element, and a slider parallel to a direction in which a compressive strain is applied to the rubber sample. A slider guide groove in which the slider is loosely fitted so that the slider can slide, and a temperature measuring point of the thermosensitive element is inserted from a side surface of the rubber sample to a center of the rubber sample. Measure the center temperature of the rubber sample. A calorific value measuring device of a rubber sample, characterized by that. The present invention also relates to a calorific value measuring device for a rubber sample, wherein a thermocouple is used as a thermosensitive element for temperature measurement in the calorific value measuring device for a rubber sample.

[0010]

In the present invention, since the position of the thermocouple contact point can be set at the center of the rubber sample, the temperature at the center of the rubber sample at which the temperature rise due to heat generation due to repeated compressive strain appears most accurately can be measured. Becomes Thereby, the calorific value of the rubber sample can be accurately measured. Further, since the thermocouple protrusion amount L from the flange at the tip of the thermocouple sheath is adjusted to the radius r of the sample, the position of the contact point of the thermocouple can be easily determined by simply inserting the thermocouple into the sample up to the flange. Can be centered on the sample. Furthermore, the vibration direction when the vibration of the sample subjected to repeated compressive strain is transmitted to the thermocouple and the thermocouple sheath is regulated in the axial direction where the compressive strain is applied to the sample by the thermocouple sheath holder, so that the The position of the contact point does not deviate from the center of the sample and the thermocouple is not damaged.

[0011]

Next, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing details of a sample holding unit of the apparatus for measuring a calorific value of a rubber sample according to the present invention. In the figure,
The sample 10, the upper anvil 11, the lower anvil 12, the thermocouple tip 13, and the tip of the thermocouple sheath 14 are surrounded by a thermostat 20, and have a constant temperature from a predetermined time before the start of the measurement to the end of the measurement. Is kept. A method of applying a static load and a dynamic load, that is, a compressive load and a compressive strain to the sample 10 by the upper anvil 11 and the lower anvil 12 is the same as the conventional method, and the description is omitted.

The thermocouple sheath 14 has a flange 14-1 at the tip thereof, and the length L from which the thermocouple 13 protrudes is made to match the radius r of the sample. Thermocouple sheath 1
4, when the position of the thermocouple contact 13-1 is aligned with the line connecting the centers of the upper anvil and the lower anvil, the holder 15 is screwed to the position where it crosses the door 21 of the thermostat 20. Attached by As shown in FIG. 2, the holder 15 has a substantially rectangular parallelepiped holder base portion 15-1 and an upper sheath holding portion 15-2 having a smaller width and depth and a higher height than the rectangular parallelepiped base portion. The sheath holding part 15-2 has a thermocouple sheath 14
And a screw hole 1 for a screw 16 for fixing the thermocouple sheath 14 to the holder 15.
5-4 are provided. The thermocouple sheath 14 is attached so that the thermocouple sheath 14 is integrated with the holder 15 by screws 16 after passing through the hole 15-3.

The door 21 of the thermostatic chamber 20 has a small door 23 having an inverted U-shaped notch cut downward from the center, and a hinge 24 at the upper part thereof, so that it can be opened upward. It has become. The opening 31 of the door 21 covered by the small door 23 has a space between the front plate 25 and the inner plate 26 such that the holder 15 is housed inside the door 21 at the time of temperature measurement. In this space, holder guides 27 and 28 are provided on the left and right sides of the holder 15 with a very small gap, as shown in FIG. 3 which is a front view of the door 21. In this space, a support member 29 for supporting the holder 15 from below is provided.
5. A guide groove 30, which is surrounded by the inner plate 26, the holder guides 27 and 28, and the support member 29 and has a space above, is formed. That is, the holder 15 is
When the thermostat 20 is viewed from the front of the container, the movement in the front and rear and left and right directions is restricted by the guide groove 30, but it is possible to move upward without any resistance and return downward.

The procedure for measuring the calorific value of the rubber sample in the apparatus of the embodiment described above will now be described. First, the sample 10 is attached to the thermocouple 13 in which the holder 15 is attached to the thermocouple sheath 14 in advance. A thermocouple 13 protruding by L from the flange 14-1 of the thermocouple sheath 14 is inserted from the central side surface of the sample 10 at right angles to the axial direction of the sample until the flange hits the sample side surface. At this time, since the L and the radius r of the sample 10 are made to coincide with each other, the contact point 13-1 of the thermocouple is accurately located at the center of the sample 10.

Next, as shown in FIG. 3, the small door 23 of the thermostat 20 is opened upward, and the sample 10 and the thermocouple sheath 14 and the holder 15 are integrated into the thermostat 20 through the opening 31. Put in. At this time, the holder 15 is accommodated in the guide groove 30 and also serves to position the sample 10.

Next, the load weight 124 is changed to the balance weight 1
In addition to the above, a compressive load is applied to the sample 10. After confirming the position of the sample 10, the small door 23 is closed, and the
0 is kept at a predetermined temperature. After the temperature reaches the inside of the sample 10, a voltage is applied to the drive motor 101 from the motor control circuit 126, and the upper anvil 11 moves up and down to repeatedly generate a compressive strain in the sample 10, and a central portion thereof is formed. Is measured by the thermocouple contact 13 and the thermometer main body 116 connected thereto.

As the upper anvil 11 is driven up and down, the sample 10 and the lower anvil 12 also vibrate up and down,
With this, the thermocouple sheath 14 vibrates up and down together with the holder 15 between the front plate 25 and the inner plate 26 of the door 21. However, the thermocouple sheath 14 is blocked by the front plate 25 and the inner plate 26 in the longitudinal direction, and has holder guides 27 and 28 in the left and right direction.
And the contact 13 of the thermocouple does not deviate from the center of the sample 10, so that correct temperature measurement can always be performed.

[0018]

As described above, according to the present invention,
Just by inserting the tip of the thermocouple to the flange of the thermocouple sheath, the contact point of the thermocouple can be accurately set at the center of the sample, so that the calorific value of the sample can be measured accurately. In addition, the holder that holds the thermocouple sheath is held so as to be able to vibrate up and down, and vibrations before and after and right and left of the holder are suppressed. There is an effect that can be prevented.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of an embodiment of an apparatus for measuring a calorific value of a rubber sample according to the present invention.

FIG. 2 is a diagram illustrating the use of an embodiment of the present invention.

FIG. 3 is a side view of a main part of the embodiment of the present invention.

FIG. 4 is an overall perspective view of a conventional Goodrich Flexometer.

FIG. 5 is an enlarged view of a main part of a conventional goodrich flexometer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Rubber sample 11 Upper anvil 12 Lower anvil 13 Thermocouple 13-1 Thermocouple contact 14 Thermocouple sheath 14-1 Flange 15 Slider 30 Slider guide groove

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) G01N 25/20 G01N 3/32 G01N 33/44 G01N 3/00

Claims (2)

(57) [Claims] An apparatus for measuring a calorific value of a rubber sample, wherein a predetermined compressive load is applied to a rubber sample held in a sample holder and a predetermined compressive strain is repeatedly applied to measure a temperature of the rubber sample. In the above, the thermosensitive element for temperature measurement to be inserted into the rubber sample, and a flange portion for projecting the temperature measuring point of the thermosensitive element by a length equal to the length from the side surface to the center of the rubber sample at the tip A thermosensitive element lead wire sheath, a slider fixed at a position of the thermosensitive element lead wire sheath at a fixed distance from a temperature measuring point of the thermosensitive element, and a direction parallel to a direction in which a compressive strain is applied to the rubber sample. A slider guide groove for loosely fitting the slider so that the slider can slide, wherein a temperature measuring point of the thermosensitive element is inserted from a side surface of the rubber sample to a center of the rubber sample. Measure the center temperature of the rubber sample Calorific value measuring device of a rubber sample, characterized in that. 2. An apparatus according to claim 1, wherein a thermocouple is used as a thermosensitive element for temperature measurement.