JP2551372B2 - Mirror holding mechanism - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mechanism for holding a scanning mirror in an optical sensor mounted on a spacecraft such as an artificial satellite. In particular, distortion generated in the mirror is small, lightweight and simple. The present invention relates to a holding mechanism for a mirror that is prevented by a structure.

[0002]

2. Description of the Related Art Various optical sensors mounted on spacecraft such as artificial satellites are equipped with scanning mirrors for terrestrial imaging and the like, and are usually provided by a holding arm provided in the optical sensor. It is held and fixed. This scanning mirror generally requires a highly accurate distortion-free state on the reflecting mirror surface, but the method of fixing and holding the mirror on the holding arm does not sufficiently adjust the flatness of the mirror and the holding arm. If not, the mirror will be distorted. Further, even when thermal expansion occurs in the mirror, the holding arm, etc. due to a change in the temperature environment, the mirror may be distorted due to a difference in expansion coefficient between the mirror and the holding arm. In particular,
Such distortion due to thermal expansion has been a serious problem in scanning mirrors in artificial satellites placed in outer space where temperature changes drastically.

Therefore, conventionally, by using a holding mechanism in which a spherical slide bearing and a ball slide bearing are combined at the joint portion of the mirror and the holding arm, the distortion of the mirror is prevented. A conventional mirror holding mechanism will be described with reference to FIG. FIG. 4 shows a conventional mirror holding mechanism, (a) is a perspective view showing the whole, (b) is a partial sectional plan view of the holding mechanism, and (c) is a front view thereof. In these figures, 1 is a scanning mirror, and 2 is this mirror 1.
Is a holding arm for holding. Reference numeral 4 denotes a holding mechanism that joins the mirror 1 and the holding arm 2 to each other, and a ball slide bearing 41 that axially supports the holding arm 2 and the ball slide bearing 41.
It is composed of a spherical plain bearing 42 that rotatably supports and a holder 43 that holds the spherical plain bearing 42, and the lower surface of the holder 43 is fixed to the rear surface of the mirror 1.
A drive shaft 5 supports the holding arm 2, and both ends thereof are held by a balance arm 6 fixed in the optical sensor.

According to the conventional mirror holding mechanism having such a structure, the ball slide bearing 41 absorbs the movement of the holding arm 2 in the axial direction and the axial rotation direction, and the spherical slide bearing 42 moves the holding arm 2 up and down. , It is possible to absorb the tilting in the left-right direction, so that when the flatness adjustment of the mirror 1 and the holding arm 2 is not sufficient, or when a difference in expansion due to heat occurs between the mirror 1 and the holding arm, The distortion of the mirror 1 was effectively prevented.

[0005]

However, the conventional mirror holding mechanism described above becomes extremely large, especially because the ball slide bearing 41 has a complicated structure, and as a result, the entire holding mechanism is extended. There has been a problem that spacecraft such as artificial satellites themselves become large and heavy. Here, the ball slide bearing 41 is used for the holding arm 2
Although the axial movement of the holding arm 2 can be absorbed over a wide range, the axial movement of the holding arm 2 when the mirror 1 is actually distorted is very small, and the ball slide bearing The ball in 41 was prevented from being distorted by rotating slightly. Therefore,
From the viewpoint of preventing the occurrence of distortion, a large-scale structure such as the ball slide bearing 41 is not always necessary, but rather the use of the ball slide bearing 41 makes it more serious to increase the size and weight of an artificial satellite or the like. It was a problem.

[0006] Although Japanese Patent Application Laid-Open No. 1-209419 proposes a technique for holding the scanning mirror, it does not disclose any technique from the viewpoint of preventing distortion of the reflecting mirror surface of the mirror.

The present invention has been proposed in order to solve the problems of the prior art as described above, and provides a lightweight, small-sized and simple structure of a mirror holding mechanism for preventing the distortion generated in the mirror. To aim.

[0008]

In order to achieve the above object, a mirror holding mechanism of the present invention is a holding mechanism for joining a scanning mirror and a holding arm for holding the scanning mirror. A pair of bearings provided on the back surface and a side surface of the holding arm that faces the mirror back surface; and a pair of spherical bodies that are rotatably fitted into the pair of bearings and that form a spherical plain bearing together with the bearings. The mirror holding mechanism is preferably provided in three places between the mirror back surface and the holding arm side surface.

[0009]

According to the mirror holding mechanism of the present invention having the above structure, the mirror generated when the flatness between the mirror and the holding arm is not sufficiently adjusted, or when a difference in expansion due to heat occurs between the mirror and the holding mechanism. Distortion is absorbed by the action of the pair of spherical plain bearings provided on the scanning mirror and the holding arm, and the shaft connecting the pair of spherical plain bearings.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the mirror holding mechanism of the present invention will be described below with reference to the drawings. FIG. 1A shows a perspective view of a scanning mirror, and FIG. 1B shows a perspective view of a state in which a holding mechanism is attached to the mirror. 2A and 2B are cross-sectional views of an essential part of an embodiment of a mirror holding mechanism of the present invention, wherein FIG. FIG. 3 shows the operating state in FIG. 2 (b). In these figures, 1 is a scanning mirror, and 2 is a holding arm. In the mirror holding mechanism of the present embodiment, these scanning mirror 1 and holding arm 2 are joined.
The holding arm 2 is supported by a drive shaft 5, and the drive shaft 5 is held at both ends by a balance arm 6 fixed in the optical sensor. The holding mechanism 3 includes a pair of bearings 31, a pair of spheres 32 that are rotatably fitted into the bearings 31 to form a spherical plain bearing together with the bearings 31, and a shaft 33 that connects the pair of spheres 32. It comprises a pair of holders 34 for holding the peripheral portions of the pair of bearing portions 31, respectively. The holder 34 has a bottomed shape in this embodiment, but the shape or the like is not particularly limited as long as it is a means for holding the spherical bearing portion 31.

In this embodiment, each end of the holding arm 2 is held by a bottomed holding portion 21.
Although the holder 34 is fixed to the bottom surface of the holder, the holder 34 can be directly attached to the holding arm 2 without providing the holding portion 21. Moreover, the holder 34 is not provided, and the bearing 31
Can also be directly fixed to the mirror 1 and the holding arm and attached. On the other hand, the holding arm 2 has a T-shape as shown in FIG. 1, and the holding mechanism 3 is provided at the tip of three places, but the present invention is not limited to this, and the flatness can be adjusted, In addition, the shape of the holding arm 2 and the number of holding mechanisms 3 are not limited as long as the mirror 1 can be held in a form capable of absorbing distortion. Further, in the present embodiment, the holding arm 2 is fixed to the balance arm 6 fixed inside the optical sensor via the drive shaft 5, but not limited to this, it may be fixed directly to the inner wall of the optical sensor or the like.

In this way, when the mirror 1 is held by the mirror holding mechanism of this embodiment, when the flatness of the mirror 1 and the holding arm 2 is not sufficiently adjusted, or the mirror 1 and the holding arm 2 are thermally expanded. When the expansion rates are different, as shown in FIG. 3, the pair of spherical plain bearings 31 and 32 respectively rotate to incline the shaft 33, so that the relative positions of the mirror 1 and the holding arm 2 are changed. Change.
Thereby, the flatness between the mirror 1 and the holding arm 2 is adjusted, and the mirror 1 and the holding arm 2 are caused by the difference in the coefficient of thermal expansion.
Since any difference in the amount of displacement between them is absorbed, the mirror 1 is not distorted. When the holding stability of the mirror 1 is insufficient here, for example, one place of the mirror holding mechanism of the present embodiment provided at three places is directly connected to the mirror 1 and the holding arm 2 without using the holding mechanism. The stability of the mirror 1 can be secured by fixing and holding it. Further, the shaft 33 that connects the pair of spherical bodies 32 may be formed of a flexible member. By doing so, the difference in the amount of displacement between the mirror and the holding arm can be absorbed more smoothly and the distortion can be reliably absorbed.

[0013]

As described above, according to the mirror holding mechanism of the present invention, the distortion that occurs in the mirror can be prevented in advance only by the lightweight, small size and simple structure.

[Brief description of drawings]

FIG. 1A is a perspective view of a scanning mirror,
(B) shows a perspective view of a state in which a holding mechanism is attached to the mirror.

2A and 2B are cross-sectional views of a main part of an embodiment of a mirror holding mechanism of the present invention, in which FIG. 2A is a longitudinal sectional view of a holding arm in a radial direction, and FIG. 2B is a longitudinal sectional view of the holding arm.

FIG. 3 shows an operating state in FIG. 2 (b).

FIG. 4 shows a conventional mirror holding mechanism, (a) is a perspective view showing a state where the holding mechanism is attached to a mirror, (b) is a partial sectional plan view of the holding mechanism, and (c) is a front view thereof. Show.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Mirror 2 ... Holding arm 3 ... Holding mechanism 4 ... Conventional holding mechanism 5 ... Drive shaft 6 ... Balance arm 21 ... Holding part 31 ... Bearing part 32 ... Sphere 33 ... Shaft 34 ... Holder 41 ... Ball slide bearing 42 ... Spherical surface Slide bearing 43 ... Holder

Claims (3)

(57) [Claims] 1. A holding mechanism for joining a scanning mirror and a holding arm for holding the scanning mirror, the holding mechanism facing the back surface of the scanning mirror and the mirror back surface of the holding arm. A pair of bearings provided on the side surfaces, a pair of spheres that are rotatably fitted into the pair of bearings and constitute a spherical plain bearing together with the bearings, and a shaft that connects the pair of spheres. A mirror holding mechanism characterized in that 2. The mirror holding mechanism according to claim 1, wherein the mirror holding mechanism is provided at three positions between the rear surface of the mirror and the side surface of the holding arm. 3. The mirror holding mechanism according to claim 1, wherein the shaft connecting the pair of spheres is made of a flexible member.