JPH0224299A - Radiating cooler - Google Patents

Abstract

PURPOSE:To carry out the opening/closing of the opening face of a shield as necessary with a simple structure by joining a cover to the shield via a linking member formed with a shape memory alloy while providing a heater for heating the linking member to a temperature higher than a transformation temperature. CONSTITUTION:Until an artificial satellite is orbited, a linking member 7 is kept at a temperature higher than a transformation temperature by means of the atmospheric temperature on the ground or a heater 8 to keep a cover 4 in a closed condition whereas, after the artificial satellite is orbited, the action of the heater 8 is stopped, allowing the linking member 7 to be naturally cooled to a temperature lower than the transformation temperature to keep the cover 4 in an open condition. Also, at the time of baking, the linking member 7 is heated to a temperature higher than the transformation temperature by means of the heater 8 to keep the cover 4 in a closed condition, thereby shutting off the radiation of heat from cooling boards 2, 3, etc. to space by means of the cover 4 to carry out baking in a short time. In an engaging means 9, the shape memory member 9a thereof becomes an engaging condition for closing the cover 4 at the temperature higher than the transformation temperature at the time of launching whereas it becomes a releasing condition in the space.

Description

[Detailed Description of the Invention] [Summary] To enable a radiation cooler for cooling objects to be cooled, such as infrared sensors, to open and close the open surface of the shield with a cover as necessary with a simple configuration. In a radiation cooler in which the object to be cooled is placed in the center of a shield with one side open, the cover is connected to the shield via a connecting member made of a shape memory material, and this connecting member is connected to the transformation temperature. Install a heater that can heat to a higher temperature,
When the connecting member is heated to a temperature higher than the transformation temperature by the heater, the cover closes the open surface of the shield, and when the connecting member is cooled to a temperature lower than the transformation temperature, the cover opens the open surface. and further, if necessary, locking a cover with the open surface of the shield closed at a temperature higher than the transformation temperature, separately from the connecting member,
A locking means is provided that releases the locking function at a temperature lower than the transformation temperature.

[Industrial application field]

The present invention relates to a radiation cooler, and particularly to a radiation cooler that has a simple configuration and allows the open surface of a shield to be opened and closed with a cover as necessary.

[Conventional technology]

A radiation cooler is used, for example, to cool an infrared sensor used in an infrared detection device mounted on an artificial satellite.

In a conventional radiation cooler, for example, as shown in FIG. 4, an infrared sensor D is placed at the center of the bottom of a shield 1 that is open on one side, and a cooling system that radiates heat into space is installed around the infrared sensor D. It has a configuration in which plates 2 and 3 are arranged. The shield 1 or the cooling plates 2 and 3 are adjusted to an angle where the infrared sensor D is not affected by heat from the earth or the sun when the artificial satellite is in a fixed orbit and is operating normally, and Its surface is also mirror-like or painted white, black, etc., so that heat can be radiated efficiently.

By the way, in space, the infrared sensor D has a temperature of about -18
0℃, shield 1 about -70℃, cooling plate 2 about -120℃
℃, since the cooling plate 3 is cooled to about -180℃,
Foreign matter such as dust from the artificial sanitary body and space is adsorbed on the inner wall surface of the shield 1, the cooling plates 2 and 3, etc., impeding the heat dissipation effect and significantly degrading the characteristics of the infrared sensor D. Therefore, in addition to the above configuration, a heater (not shown) is provided along the inside of the radiation surface of the shield 1 and the cooling plates 2 and 3, and the heater periodically cools the shields vi, 2 and 3 and the shield 1.
So-called baking is a process in which foreign matter adhering to the surface of a material is removed by heating it.

Since the open surface of the shield of a radiation cooler with such a configuration and function does not require a cover while it is being naturally cooled in space, conventionally a configuration without a cover mechanism was used. There were many.

In addition, some satellites are equipped with a cover mechanism to prevent infrared sensors from being exposed to sunlight or radiation from the earth depending on the orientation of the satellite during or after launch until the satellite enters orbit.

[Problem to be solved by the invention]

When a radiation cooler without a cover mechanism is mounted on an artificial satellite, there is a problem in that the attitude must be controlled so that sunlight or radiation from the earth does not directly enter the infrared sensor. Also, during baking, while heating the shield 1 and cooling plates 2 and 3, a large amount of heat is radiated into space from the cooling plates 2 and 3, resulting in poor heating efficiency and the need to use a large-capacity heater. There was a drawback that deposits could not be removed.

A device with the above-mentioned cover mechanism can solve the above-mentioned drawbacks from the time it is launched until it enters a geostationary orbit, but its structure is complicated, and - once the cover is opened, it cannot be closed again, so it cannot be baked. Similar to the one without a cover, a heater with a large capacity is sometimes required.

The present invention has been made in consideration of the above circumstances, and it is an object of the present invention to provide a radiation cooler with a simple configuration and a cover that allows the open surface of the shield to be opened and closed as necessary. be.

[Means to solve the problem]

This invention employs the following means to achieve the above object. That is, as shown in FIGS. 1 and 2,
In a radiation cooler in which an object to be cooled, such as an infrared sensor D, is arranged in the center of a shield 1 with one side open, the cover 4 is coupled to the shield 1 via a coupling member 7 made of a shape memory member, and this coupling A heater 8 capable of heating the member 7 to a temperature higher than the transformation temperature is provided, and when the connecting member 7 is heated to a higher temperature than the transformation temperature by the heater 8, the cover 4
is in a state in which the open surface of the shield 1 is closed, and the cover 4 is in a state in which the open surface is in an open state when the connecting member 7 is cooled to a temperature lower than the transformation temperature.

In addition to the above-mentioned connecting member 7, the open surface of the shield 1 is locked in a closed state with the cover 4 at a temperature higher than the transformation temperature,
A locking means 9 made of a shape memory member whose locking function is released at a temperature lower than the transformation temperature may be provided as necessary.

[Effect]

In the radiation cooler of the present invention, the cover 4 is maintained at a temperature higher than the transformation temperature by the atmospheric temperature on the ground or by the heater 8 until the satellite is placed in orbit.
After the satellite is placed in orbit, the operation of the heater 8 is stopped and the connecting member 7 is closed.
The cover 4 can be placed in an open state by naturally cooling it to a temperature lower than the transformation temperature.

In addition, during baking, by heating the connecting member 7 to a temperature higher than the transformation temperature with the heater 8 and closing the cover 4, the heat radiation from the cooling plates 2, 3, etc. to space is blocked by the cover 4. Can perform baking in time.

The locking means 9, which is provided separately from the connecting member 7, is in a locking state in which the shape memory member 9a locks the cover 4 in the closed state at room temperature at the time of launch (higher temperature than the i-transformation temperature), and the In space (lower temperature than the transformation temperature), the locking function is released and the locking function is released.

This allows the connecting means 7 to withstand the impact during launch and support the cover 4, and does not interfere with the opening/closing operation of the connecting member 7 of the cover 4 after entering the orbit.

〔Example〕

FIGS. 1 and 2 are cross-sectional views of one embodiment of the radiation cooler according to the present invention, each showing a different operating state. Further, FIG. 3 is a configuration diagram of the radiation cooler according to the above embodiment mounted on an artificial satellite.

As shown in FIG. 3, this radiation cooler RC is provided to cool an infrared sensor D mounted on an artificial satellite S. The infrared rays transmitted through the mirror M are sent to the infrared sensor D.
It orbits in a predetermined orbit while its attitude is controlled to guide it.

As shown in FIGS. 1 and 2, the radiation cooler RC includes first and second cooling elements 2.3 that radiate heat conducted from an infrared sensor D placed at the center of the bottom of the shield l below. ,
The infrared sensor D includes a shield 1 that shields the first and second cooling plates 2 and 3 from sunlight and earth radiant heat, and a cover 4 that opens and closes the open surface of the shield 1. The artificial hygiene, cover 4, and connecting member 7 each have a structure insulated with a heat insulating material (not shown).

The cover 4 is connected to the open end side of the lower peripheral wall 1a of the shield 1 via a connecting member 7 made of a shape memory alloy. This connecting member 7 has a transformation temperature lower than room temperature,
At temperatures higher than the transformation temperature, the shield 1 takes on a "■" shape, and the open surface of the shield 1 is closed by the cover 4, as shown in FIG. 1 or FIG. Further, at a temperature lower than the transformation temperature, the cover 4 becomes a flat plate as shown in FIG.
The open side of is in an open state.

Further, a heater 8 is attached to the connecting member 7 to heat it to a temperature higher than the transformation temperature.

A locking means 9 for locking the cover 4 in the closed state is attached to the open end side of the lower peripheral wall 1b of the shield 1. This locking means 9 is also made of a shape memory member 9a, and when the temperature is higher than the transformation temperature, the shape memory member 9a takes an inverted rVJ shape and locks the cover 4 in the closed state, and when the temperature is lower than the transformation temperature, the shape memory member 9a retains the shape. The memory member 9a takes on a flat plate shape or a "<" shape, and the locking function is released.

The inner circumferential surface of the shield 1 is mirror-shaped, the first cooling plate 2 is painted with white paint that particularly reflects sunlight wavelength rays, and the second cooling plate 3 has a high heat dissipation effect. Painted with black paint. In addition, a shield 1 is provided to prevent direct sunlight from entering the second cooling plate 3 or the infrared sensor D.
The angle is adjusted and the attitude is controlled.

In this radiation cooler RC, as shown in FIGS. 1 and 3, from the time the artificial satellite S is launched until it enters the orbit, the shape memory member is operated by activating the heater 8 of the connecting member 7. 8 into an rVJ shape and keep the cover 4 closed. Moreover, the shape memory member 9a of the locking means 9
When the satellite S is launched (at room temperature), it forms a reverse rVJ shape and locks the cover 4 at a position facing the connecting member 7,
This prevents the cover 4 from coming off due to the impact of the launch. When the satellite goes out into space, the shape memory member 9a becomes flat or in the shape of a "<" character and the cover 4 is unlocked, but this is not a problem at this point because no large impact will be applied to the satellite.

After the satellite S enters the orbit, the operation of the heater 8 is stopped, and as shown in FIG.
leave it open.

As described above, if the open surface of the shield l is closed with the cover 4 until the satellite S enters orbit, sunlight and radiation from the earth will be transmitted to the infrared sensor D, the first cooling plate 2 and the second cooling plate.
It is possible to prevent the infrared rays from entering the cooling plate 3, prevent the temperature of the infrared sensor D from rising due to solar heat or radiant heat from the earth, and prevent the infrared sensor D from malfunctioning due to the temperature rise, and posture control becomes easier. Furthermore, as shown in FIG. 3, the cover 4 opens toward the earth around the open end of the lower peripheral wall 1a of the shield l, so that radiation from the earth is prevented from entering the first cooling plate 2 and the second cooling plate 3. This can be prevented more reliably and the radiation cooling effect can be further enhanced.

The infrared sensor D is operated under the above conditions. In space, the infrared sensor D is at about -180°C, the shield 1 is at about -70°C, the cooling plate 2 is at about -120°C, and the cooling plate 3 is at about -180°C. Since it is cooled to -180°C, it is inevitable that foreign matter such as dust from the artificial sanitary body and outer space will adhere to it from the surroundings.

Therefore, when the cooling performance decreases due to foreign matter adhering to the first cooling plate 2 or the second cooling plate 3, or if the shield 1 or the first cooling plate 2 and the second cooling plate 3 are periodically A baking process is performed in which the material is heated to a high temperature to release the deposits. When performing this baking, the connecting member 7 is heated to a temperature higher than the transformation temperature with the heater 8 and the open surface of the shield 1 is closed with the cover 4, so that the shield 1 and the cooling plates 2 and 3 are exposed to space. shield 4 or the first and second shields.
By heating the cooling plate with a baking heater (not shown), the shield 1 and the cooling plates 2 and 3 are heated to a high temperature (for example, around 40° C.). As a result, foreign matter adhering to the shield 1 and the cooling plates 2 and 3 are adsorbed to the inner surface of the cover 4 which is at a low temperature (for example, around -50°C), and baking is completed, but at this time, the shield 1 is covered with the cover 4. Therefore, baking can be done efficiently in a short time.

When baking is completed, the operation of the heater 8 is stopped,
The connecting member 7 is cooled to a temperature lower than the transformation temperature by natural cooling, the cover 4 is opened, and the radiative cooling is restarted.

In addition to the shape memory alloy described above, shape memory resins such as polynorbornene and transisopropylene can be used as the shape memory member.

〔Effect of the invention〕

As explained above, according to the radiation cooler of the present invention,
During baking, the cover can be closed by heating the connecting member to a temperature higher than the transformation temperature using a heater.
By closing the cover, heat radiation from the cooling plate to space is reduced, baking can be performed in a short time, and cooling performance can be restored. Further, the structure of opening and closing the cover by deforming the connecting member made of a shape memory member is simple and can be implemented at low cost.

[Brief explanation of the drawing]

Fig. 1 is a vertical cross-sectional view of the embodiment with the cover closed, Fig. 2 is a longitudinal cross-sectional view of the embodiment with the cover open, and Fig. 3 is a configuration diagram of the radiant cooler according to the embodiment when installed on an artificial satellite. , FIG. 4 is a longitudinal sectional view of a conventional example. In the figure, 1... Shield, 2... First cooling plate, 3...
2nd cooling plate, 4...Cover 7...Connection member, 8...Heater. Diagram

Claims (1)

[Claims] [1] In a radiation cooler in which the object to be cooled is arranged in the center of a shield (1) with one side open, the cover (4) is connected via a connecting member (7) made of a shape memory member. shield (
1) and is provided with a heater (8) capable of heating the connecting member (7) to a temperature higher than the transformation temperature, and when the connecting member (7) is heated to a higher temperature than the transformation temperature by the heater (8), the cover (4) closes the open surface of the shield (1), and when the connecting member (7) is cooled to a temperature below the transformation temperature, the cover (4) is configured to open the open surface. A radiation cooler featuring: [2] Separately from the connecting member (7), a cover (4) is provided with the open surface of the shield (1) closed at a temperature higher than the transformation temperature.
2. The radiation cooler according to claim 1, further comprising a locking means (9) made of a shape memory member that locks the locking member (9) and releases the locking function at a temperature lower than the transformation temperature.