JPH05126709A - Hardness measuring device - Google Patents

Abstract

PURPOSE:To obtain a hardness measuring device which cam measure a hardness corresponding to a temperature highly accurately where a usage temperature range is wider than before. CONSTITUTION:This device is placed within a measurement atmosphere which is at 0 deg.C or lower along with a material 2 to be measured consisting of a rubber, etc., and then the material 2 to be measured in cooled fully. A temperature within a heat-insulation cover 1 which is blanked off by an expansion and contraction sheet 10 is controlled by a heater 3. By moving a hardness meter 7 toward a lower part at a constant speed by operating a lever 6, a constant load is applied to a surface of the material 2 to be measured through a press needle 8. Since the press needle 8 is displaced according to the hardness of the material 2 to be measured, the hardness meter 7 measures a hardness of the material 2 to be measured based on an amount of displacement of the press needle 8 and displays the measurement result on a display 9 as a digital value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hardness measuring device for measuring the hardness of an elastic body such as rubber constituting a pneumatic tire, and particularly, for measuring the hardness of a material to be measured with high accuracy in various temperature ranges. Regarding the device.

[0002]

2. Description of the Related Art Conventionally, as a device for measuring the hardness of an elastic body such as rubber, Japanese Patent Publication No. 2-57260 and Japanese Patent Publication No.
57261 and Japanese Patent Publication No. 2-57659. In these digital hardness meters, a constant load is applied to the surface of the material to be measured via a push needle, and the hardness of the material to be measured is measured as a digital value based on the displacement of the push needle. ..

[0003]

However, in the conventional hardness measuring apparatus, since the electronic parts are used as the constituent parts, the operating temperature range thereof is limited to about 0 to 40 ° C. On the other hand, when measuring the hardness of rubber or the like that constitutes a pneumatic tire, it is necessary to consider the practical environment of the pneumatic tire, so it is required to measure the hardness of the measured material in a temperature range other than the above. There is. In such cases, heat or cool the sample of the material to be measured such as rubber,
After that, the sample is taken out to room temperature and the hardness is measured.However, even if the material to be measured has low thermal conductivity, the temperature changes during the transfer of the sample, and the hardness corresponding to the temperature must be accurately measured. I couldn't. Further, since it is necessary to transfer the sample, the work of hardness measurement is complicated. An object of the present invention is to provide a hardness measuring device which has a wider operating temperature range than conventional ones and can measure hardness corresponding to temperature with high accuracy.

[0004]

A hardness measuring device according to the present invention moves downward at a constant speed to exert a constant load on a surface of a material to be measured via a pressing needle, and the displacement amount of the pressing needle. Based on the digital hardness meter for measuring the hardness of the material to be measured, one end closed type heat insulating cover covering the hardness meter, at least the push needle is exposed to the open end of the heat insulating cover. It has a stretchable sheet to be closed, a control heater for controlling the temperature inside the heat insulating cover, and an indicator for displaying the measurement result of the hardness meter outside the heat insulating cover.

In the present invention, the electronic component of the digital hardness meter is thermally isolated from the measurement atmosphere by the one-end closed type heat insulating cover and the stretchable sheet closing the open end of the heat insulating cover, and the heat insulation is performed. Since the temperature inside the cover is controlled by the control heater, the operating temperature range of the hardness measuring device can be made wider than before. For this reason,
Since it is not necessary to transfer a heated or cooled sample as in the prior art, the work of hardness measurement is simple, and the hardness corresponding to the target specific temperature can be accurately measured.

In the present invention, as the material of the heat insulating cover, any material may be used as long as it is lightweight and has a heat insulating property capable of thermally separating the measurement atmosphere and the inside of the heat insulating cover, and styrene foam or the like can be used. Further, as the material of the stretchable sheet, it is preferable that it has a slight heat insulating property and does not suppress the vertical movement of the hardness meter, and a silicone rubber sheet or vinyl can be used.

Further, in the present invention, since the hardness meter moves downward in the heat insulating cover at a constant speed to apply a constant load to the surface of the material to be measured through the pressing needle, the displacement of the pressing needle is increased. It is possible to measure the hardness of the material to be measured based on the above with a small variation due to a person with high accuracy. Further, by operating the vertical movement of the hardness meter remotely, the hardness can be measured in the state where a large sample such as a pneumatic tire is placed in the environmental test chamber.

The hardness measurement result of the material to be measured is
It is displayed on the display installed inside or outside the heat insulation cover. When installing this indicator inside the heat insulation cover,
A window is provided on the heat insulating cover, and measurement results can be displayed on the outside of the heat insulating cover through the window.

[0009]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a sectional view showing a hardness measuring device according to an embodiment of the present invention. In FIG. 1, a one-end closed type heat insulating cover 1 made of styrofoam is supported by a support frame (not shown) above the measured material 2 with its open end facing downward. The heater 3 is attached to the inner surface of the heat insulating cover 1, and is controlled by the heater controller 4 outside the heat insulating cover 1. The constant speed vertical movement device 5 moves up and down in the heat insulating cover 1 by operating the lever 6. An air damper is built in the constant speed vertical movement device 5 so that a constant speed is maintained when moving downward. Further, an appropriate drive means is provided in place of the lever 6, and the constant speed vertical movement device 5 is remotely operated.
May be moved up and down. The digital hardness meter 7 is attached to the lower end of the constant speed vertical movement device 5 and moves up and down together with the constant speed vertical movement device 5. The hardness meter 7 measures the hardness of the material 2 to be measured based on the amount of displacement of the push needle 8 provided under the hardness meter 7 and displays the measurement result on the display 9 outside the heat insulating cover 1. A stretchable sheet 10 made of a silicone rubber sheet or vinyl exposes at least the pressing needle 8 and closes the open end of the heat insulating cover 1.

Next, the operation of the above hardness measuring device will be described. First, the device of the present invention is placed together with the material to be measured 2 made of rubber or the like in a measurement atmosphere at 0 ° C. or lower,
The material to be measured 2 is sufficiently cooled. On the other hand, the temperature inside the heat insulating cover 1 is controlled to, for example, 10 ° C. by the heater 3. Next, by operating the lever 6 to move the hardness meter 7 downward at a constant speed, a constant load is applied to the surface of the material 2 to be measured via the push needle 8. At this time, since the push needle 8 is displaced according to the hardness of the material 2 to be measured, the hardness meter 7 is operated by the push needle 8.
The hardness of the material 2 to be measured is measured on the basis of the amount of shift of, and the measurement result is displayed on the display 9 as a digital value.

According to this embodiment, the heat insulating cover 1 and the elastic sheet 10 thermally isolate the electronic components of the hardness meter 7 from the measurement atmosphere, and the heater 3 controls the temperature inside the heat insulating cover 1. Even if the temperature of the measurement atmosphere is 0 ° or less, the hardness meter 7 does not have any abnormality. Further, similarly, even if the temperature of the measurement atmosphere is 40 ° or more, the hardness meter 7 does not have any abnormality, and the operating temperature range of the hardness measuring device can be made wider than before.
Therefore, the hardness measurement work is easier than in the past, and the hardness corresponding to the temperature can be accurately measured.

Further, the hardness meter 7 moves downward at a constant speed in the heat insulating cover 1 in conjunction with the constant speed vertical movement device 5 to apply a constant load on the surface of the material 2 to be measured via the push needle 8. Therefore, it is possible to measure the hardness of the material to be measured 2 with high accuracy by reducing the variation due to human. Further, if the vertical movement of the hardness meter 7 can be remotely controlled, the hardness can be measured in a state where a large sample such as a pneumatic tire is placed in the environmental test chamber.

[0013]

As described above, according to the present invention, the electronic components of the digital hardness meter are thermally isolated from the measurement atmosphere by the heat insulating cover and the elastic sheet, and the temperature inside the heat insulating cover is controlled. Since the temperature is controlled by the heater, the operating temperature range of the hardness measuring device can be made wider than before. Therefore, the hardness measurement work is simpler than in the past, and the hardness corresponding to the target specific temperature can be accurately measured. Further, according to the present invention, the hardness can be accurately measured in consideration of the practical environment such as a pneumatic tire.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a hardness measuring device according to an embodiment of the present invention.

[Explanation of symbols]

 1 Heat Insulation Cover 2 Material to be Measured 3 Heater 4 Heater Controller 5 Constant Speed Vertical Movement Device 6 Lever 7 Hardness Meter 8 Push Needle 9 Indicator 10 Stretchable Sheet

Claims (1)

[Claims] 1. A digital device for measuring a hardness of a material to be measured based on a displacement amount of the needle by causing a constant load to act on the surface of the material to be measured by moving the material downward at a constant speed. -Type hardness meter, a heat-insulating cover of one end closed type that covers the hardness meter, a stretchable sheet that exposes at least the push needle to close the open end of the heat-insulating cover, and the temperature inside the heat-insulating cover A hardness measuring device having a control heater for controlling the temperature and a display for displaying the measurement result of the hardness meter on the outside of the heat insulating cover.