JPS5945098B2 - Thermal resistance measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel thermal resistance measuring device that can measure the thermal resistance value of each device in a satellite even when it is incorporated into a system such as an artificial satellite.

Generally, the thermal resistance value of electronic equipment is a very important parameter in the thermal design of the system, but at present there is no measuring device that directly measures this value. Values calculated by analysis of the physical property constants of the material are used.

On the other hand, the components of thermal resistance are thermal conduction resistance and thermal radiation resistance, but the thermal resistance value of electronic equipment when installed as a system such as an artificial satellite is thermal radiation resistance between each device. depends on the degree of radiative coupling.

・Thermal conduction resistance depends on the mounting condition of the equipment and equipment panel.

For these reasons, the values calculated by the method shown above cannot be used directly.

The present invention relates to a thermal resistance measuring device designed to solve the above-mentioned drawbacks.

An embodiment of the present invention will be described below with reference to the drawings.
In FIG. 1, the thermal resistance measuring device includes a heating element 1 such as a heater, a temperature sensor 2 such as a thermistor, a control section 3, a data storage section 4, an arithmetic section 5, an output section 6, and an analog/digital conversion section T). It is composed of a timer section 8. Also,
Reference numeral 9 indicates an object to be measured such as an electronic device mounted on a satellite tower. The thermal resistance value of the object to be measured 9 is measured according to the following principle.

That is, when the heating element 1 heats the object 9 to be measured and the temperature reaches a steady state, the output of the temperature sensor 2 provided near the object to be measured is fed back to the control section 3 through the data storage section 4, and the control is performed. When the heat generation is stopped under the control of the control section 3, the data storage section 4 records a temperature change as shown in FIG. characteristics are obtained. Here, the vertical axis in FIG. 2 is absolute temperature, and the horizontal axis is time.

Also, the time. The temperature of T. , the temperature at time tl is Ti,
The temperature at time 2 is T2, the temperature at time 3 is T3, and T
o is the initial temperature, and the interval between time tl and time 2 and the interval between time 2 and time 3 are equally spaced. Here, the temperature change characteristics shown in FIG. 2 can be treated as a thermal circuit similar to a C-R circuit having a constant current source in a vacuum, so the heating element 1, the temperature sensor 2, and If the object to be measured 9 is installed in a vacuum device such as a space chamber, it can be expressed by equation (1).

Here, by using the temperature change characteristics shown in FIG. 2, the thermal resistance value can be calculated using equation (2).

On the other hand, the heat capacity C of a device is defined as the product of the specific heat and weight of the device, so if this value is input into the calculation unit 5 in advance, the data collected in the data storage unit 4 can be stored in analog form.
After being digitized by the digital conversion section 8, the thermal resistance can be calculated by the calculation section 5 and displayed on the output section 6.

In the thermal resistance measuring device, the heating element 1 and the temperature sensor 2 are small and lightweight, and can be easily attached to equipment inside an artificial satellite.

Therefore, by using the thermal resistance measuring device of the present invention, even if the device is incorporated into a large system, the thermal resistance value can be easily measured during a thermal vacuum test or the like without any modification.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention, and FIG. 2 is a diagram showing temperature change characteristics in the vicinity of the object to be measured. In the figure, 1 is a heating element, 2 is a temperature sensor, 3 is a control section, 4 is a data storage section, 5 is a calculation section, 6 is an output section, 7 is an analog/digital conversion section, 8 is a timer section, and 9 is a It is the object to be measured.

Claims (1)

[Claims] 1. An object to be measured that is heated in a vacuum, a temperature measuring means that is installed near the object to be measured and measures the temperature near the object to be measured, and when the temperature near the object to be measured reaches a predetermined temperature. A control means for stopping heating of the object to be measured;
A recording means records temperature changes in the vicinity of the object to be measured based on the output of the control means, and temperature values T_0, T_1, . . . at times t_0, t_1, . - A thermal resistance measuring device comprising a calculation means for determining T_n and calculating a thermal resistance value from this, and an output means for outputting the calculated thermal resistance value.