JPH02279499A - Thermal switch - Google Patents

Abstract

PURPOSE:To prevent effect due to the temperature change of a heat radiating body, and at the same time, make a weight light, by making a constitution so that heat conduction between an exothermic body and a heating body which furnishes this exothermic body, may be changed by expanding/contracting a piezoelectric body in opposition to a temperature change. CONSTITUTION:When the temperature of a mounted apparatus 5 has risen, a temperature sensor 9 inspects this, and an inspection signal is inputted into a voltage impression circuit 10. Also, a piezoelectric body 3 is impressed with voltage through the voltage impression circuit 10. And an upper part housing 1 is pushed up by expanding the piezoelectric body 3, and its flange portion 11 is closely welded to the flange portion 21 of a lower part housing 2. As a result, the exothermic body of the mounted apparatus 5 is conducted to a heat radiating panel 8 through the upper and lower housing 1, 2, and thus, the temperature of the mounted apparatus 5 is restrained. Meanwhile, when the temperature of the mounted apparatus 5 has dropped to a value which is less than a set value, an impression voltage to the piezoelectric body 3 is cut off, and the piezoelectric body 3 is contracted. As a result, both flange portions 11, 12 are separated, and the temperature drop of the mounted apparatus 5 is restrained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thermal switch, and particularly to a thermal switch mounted on an artificial satellite.

[Conventional technology]

Conventionally, heat-generating equipment mounted on artificial satellites is directly attached to a discharge panel, and by setting the infrared emissivity of the heat-radiating panel to an appropriate value, the heat generated by the on-board equipment is radiated from the heat-radiating panel into space. It controlled the temperature of onboard equipment.

[Problem to be solved by the invention]

In the conventional thermal switch described above, when the heat generation of the installed equipment decreases, the heat flow to the heat dissipation panel decreases, causing the temperature of the heat dissipation panel to drop.As a result, the temperature of the mounted equipment directly attached to the heat dissipation panel also decreases. This has the drawback that the temperature of the installed equipment is directly affected by temperature changes in the heat dissipation panel.

[Means to solve the problem]

The thermal switch of the present invention is a thermal switch that controls heat conduction from a heat generating element to a heat radiating element, and includes an upper housing that is coupled to the heat generating element and has a first flange portion on a surface facing the coupling surface thereof; a second flange portion facing the first flange portion on a surface that is connected to the body and opposite to the connecting surface thereof;
a lower housing having a flange portion; a heat transfer layer provided between the first flange portion and the second flange portion; and a piezoelectric body arranged in close contact with each other with a heat transfer layer in between.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view showing one embodiment of the present invention.

As shown in FIG. 1, an upper housing 1 fixed to a heat-generating mounted device 5 with screws 6 and a lower housing 2 fixed to a heat dissipation panel 8 with screws 7 are made of a material with high thermal conductivity, such as an aluminum alloy. The first flange portion 11 is provided on the surface of the upper housing 1 facing the mounting surface to the mounted equipment 5, and the first flange portion 11 is provided on the surface facing the surface of the lower housing 2 facing the mounting surface to the heat dissipation panel 8. and flange part 1
A heat transfer layer 4 is disposed between the heat transfer layer 1 and a second flange portion 21 provided opposite to the heat transfer layer 4 .

Further, the upper housing 1 and the lower housing 2 are connected by a piezoelectric body 3 that expands and contracts when voltage is applied. When the piezoelectric body 3 is contracted, a gap is provided between the flange portions 11 and 21 with the heat transfer layer sandwiched between them, and when the piezoelectric body 3 is expanded, a gap is provided between the flange portions 11 and 21. They are pressed together via a thermal layer 4. That is, the heat transfer layer 4 is made of a soft material with relatively good thermal conductivity, such as indium, and is bonded to the upper surface of the flange portion 11, so that when the upper housing 1 is pushed up by an external force, the flange The portion 11 is brought into close contact with the flange portion 21 of the lower housing 2 via the heat transfer layer 4.

Further, the mounted equipment 5 is provided with a temperature sensor 9, and a voltage application circuit]0 that is controlled by the detection current of the temperature sensor 9 and applies a voltage to the piezoelectric body 3.

Next, the operation of this embodiment will be explained with reference to FIG.

The temperature sensor 9 is attached to the mounted equipment 5 and sends a detection output to the voltage application circuit 10. Voltage application circuit lO
applies a voltage to the piezoelectric body 3 when the detection output from the temperature sensor 9 exceeds a preset value, and cuts off the voltage to the piezoelectric body 3 when the detected output falls below a preset value. Make it.

Generally, a piezoelectric body expands and contracts depending on the applied voltage, so by setting the gap length between the flange portions 11 and 21 to a value corresponding to the direction of expansion and contraction and the amount of displacement of the piezoelectric body 3,
When voltage is applied, the flange portion 11 of the upper housing 1 and the flange portion 21 of the lower housing 2 can be brought into close contact 9 Now, if the temperature of the mounted equipment 5 rises and exceeds a preset value, the temperature sensor 9 detects this, and the voltage application circuit 10 applies a voltage to the piezoelectric body 3. Piezoelectric body 3
extends and pushes the upper housing 1, and the flange part 1
1 and the flange portion 21 are in close contact with each other, heat generated by the mounted equipment 5 flows to the heat radiation panel 8 via the upper housing 1 and the lower housing 2, and the temperature rise of the mounted equipment 5 is suppressed and maintained at an appropriate temperature.

Conversely, when the temperature of the mounted device 5 falls below a preset value, the voltage application circuit 10 cuts off the voltage applied to the piezoelectric body 3, so the piezoelectric body 3'' contracts, and the flange portion 11 and the flange Since the thermal switch of the present invention is separated from the heating element and the heat radiating element to which it is attached, the heat flow is stopped and the temperature drop of the mounted equipment 5 is suppressed. The piezoelectric material expands and contracts in response to temperature changes to change the heat conduction between the parts, which has the effect of preventing it from being affected by temperature changes in the heat sink, and also meets the requirements of equipment onboard satellites. This has the effect of reducing weight.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing one embodiment of the present invention. 1... Upper housing, ... Piezoelectric body, 4... Heat transfer foil, Screw, 8...heat dissipation panel, Voltage application circuit, 11.2

Claims (1)

[Claims] A thermal switch for controlling heat conduction from a heating element to a heat radiating element, comprising: an upper housing having a first flange portion on a surface that is coupled to the heating element and faces the coupling surface; and an upper housing that is coupled to the heat radiating element and has a coupling surface thereof. a lower housing having a second flange portion facing the first flange portion on a surface facing the first flange portion; a heat transfer foil provided between the first flange portion and the second flange portion; A thermal switch characterized in that the first flange portion and the second flange portion include a piezoelectric body arranged so as to be brought into close contact with each other with the heat transfer foil sandwiched therebetween by an applied voltage.