JPH0814404A - Ring-shaped seal - Google Patents

Abstract

PURPOSE:To set optimally the pressing contact force to a slide contacting surface by furnishing a ring-shaped contacting piece to be in resilient contact with the slide contacting surface and a ring-shaped fluid accommodation part in which the pressing force pf the ring-shaped contacting piece to the slide contacting surface can be set with the pressure of the fluid flowing into the inside. CONSTITUTION:When applied to an infrared ray sensing device to be mounted in a specified position on an airplane, a ring-shaped seal 32 is located at the periphery on the outside in order to shield a bearing 6 and inside thereof against the external environment, and thereby foreign matter such as water, moisture, dust. etc., is prevented from intruding. The ring--shaped seal 32 is fitted in a ring-shaped groove 25 formed at the peripheral surface of a supporting arm 12 confronting the slide contacting surface 19 of the base part 5, and at the oversurface, ring-shaped contacting pieces in V-shape 36, 37 are formed in a single piece structure. These ring-shaped contacting pieces 36, 37 are pressed to the slide contacting surface 19 when fluid pressure is supplied to a fluid accommodation part 38 from a fluid supplying means 39 through a tube 41, and thereby the contacting force to the slide contacting surface 19 is increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel annular seal which elastically contacts a sliding contact surface and seals between the sliding contact surface and the sliding contact surface.

Sealing between opposing parts of a rotating or rotating part to shield the inside and outside is applied in various fields. For example, even in a precise radio wave device or an optical device in the visible or invisible light range, it is necessary to direct the required direction, and a high-precision drive control device is used to seal the parts that rotate or rotate with each other. The spaces are shielded to prevent foreign matter such as dust from entering.

When such devices are mounted on a moving body such as an aircraft, a flying body, a vehicle, or a ship, a stable posture can be maintained by eliminating the influence of shaking or the like and maintaining a posture toward a target object. For positioning, the gimbal device is attached via a high-performance gimbal device, and the gimbal device is maintained stably by automatic control.

Regarding the seal of the rotating or rotating part of each device as described above, it is necessary to have a reliable sealing function for the control operation, and the seal pressure should be as high as possible in response to the control of the device. It is also essential not to be affected by fluctuations in

An optical device mounted on an aircraft, for example, an infrared detection device 1 shown in FIG. 9 has a biaxially controlled gimbal device having an X-axis 2 in the left-right direction in the drawing and a Z-axis 3 in the front and front directions in the drawing. , About each axis is rotated by a servo control signal from a predetermined rotation control device (not shown).

Incidentally, the drawing is a schematic view of only a main part shown in a front view cross-section, and detailed details thereof are omitted.
The diagonal lines showing the cross section are also omitted because the figure becomes complicated. The following portions supported by the bearings 6 and 7 of the mounting base 5 with the Z-axis 3 as the vertical direction are rotated about the Z-axis 3 in the horizontal direction, and both of the main body 8 with the X-axis 2 as the horizontal direction. The main body 8 supported by the bearings 13 and 14 on the side of the support arm 12 that supports the shafts 9 and 11 is caused to rotate about the X axis 2 in the elevation direction, respectively, and the main body 8 is always intended. Can be directed in the direction of.

The device 1 is mounted and mounted at a predetermined position on an aircraft or the like, but is exposed so as to come into contact with the outside environment of the state of being exposed to the outside of the body. Therefore, in order to keep the bearings 6, 7, 13, 14 and the inner side thereof from the external environment so that foreign matter such as moisture, moisture and dust does not enter, the annular seals 15, 1 are provided around the outer side.
Place 6,17.

FIG. 10 shows a state in which the annular seals 15, 16 and 17 are enlarged only on one side from the center and are shown in cross section.

[0009]

2. Description of the Related Art FIG. 10 typically shows a portion of an annular seal 15 which is a rotating portion of a base portion 5 and a support arm 12, and this portion will be described. However, other portions are basically the same. Please understand.

FIG. 10 (a) shows a horizontal V-shaped annular seal 15a, and FIG. 10 (b) shows a vertical V-shaped annular seal 15b. In addition, such an annular seal 15
Is generally a synthetic rubber molding.

The V-shaped annular seal 15a shown in FIG. 3A is fitted in the groove 18 formed in the support arm 12 and the V-groove side is directed to the inside A of the apparatus. The annular contact piece 21 that comes into contact with the sliding contact surface 19 of the base portion 5 is pressed by the restoring force against the pressing force pressed by the sliding contact surface 19 by a predetermined amount, thereby reliably blocking the entry of foreign matter.

As described above, the contact with the sliding contact surface 19 by the restoring force pressed to close the V-shaped opening means that when the atmospheric pressure on the outer side B decreases, the atmospheric pressure on the inner side A remains constant. However, a relative atmospheric pressure difference is generated and the inside A becomes higher. As a result, an action force for pressing the annular contact piece 21 against the sliding contact surface 19 is applied, and friction resistance due to the one-layer annular seal 15a is generated.

This is because the frictional resistance is not constant and changes indefinitely due to the atmospheric pressure difference based on the altitude difference, so that the drive motor for control is rotated around the X-axis 2 or the Z-axis 3. Since the load on the control is not constant, the stability of the control accuracy is affected to a considerable extent. In order to avoid the influence and stabilize, the drive control system becomes large and the weight and power consumption increase.

The V-shaped annular seal 15b shown in FIG. 1B is fitted in the groove 18 formed in the support arm 12 and the V groove side is directed to the sliding contact surface 19 of the base 5. The annular contact pieces 22 and 23 contacting the sliding contact surface 19 are pressed against each other by a restoring force with respect to the pressing force pressed by the sliding contact surface 19 by a predetermined amount, thereby reliably blocking the entry of foreign matter.

The contact with the sliding contact surface 19 by the restoring force pressed to open the V-shaped opening 24 means that the outer side B
When the atmospheric pressure decreases, the external contact piece 23 is pressed and deformed in the external B direction by the atmospheric pressure in the V-shaped opening 24, and the contact pressure on the sliding contact surface 19 decreases. This reduces the frictional resistance with the sliding contact surface 19.

The pressure on the inner side A of the one contact piece 22 on the inner side becomes relatively higher than that on the outer side B, so that the V-shaped opening 2 is formed.
The pressure based on the pressure difference with the inside of 4 becomes an acting force to push the contact piece 22 on the inner side toward the outer side B, and the sliding contact surface 1
The contact pressure on 9 will increase.

Such a thing will be described with reference to FIG. FIG. 11 schematically shows only the annular seal 15b. FIG. 11A is a plan view, FIG.
Figure (c) is a partially enlarged view of Figure (b).

As described above, the pressure on the inner side A acting on the contact piece 22 on the inner side is P ₁ and the pressure on the outer side B is P _2, and in this case, P ₁ > P ₂ . As a result, the pressure difference P ₁ −
It is represented by P ₂ = P.

When the radius from the center C of the inner contact piece 22 is r, the contact width is b, the inclination angle is α, and the friction coefficient with the sliding contact surface 19 is μ, the sliding contact surface 19 due to the pressure difference P is given. The pressing force q generated between and is: q = P · sin α (1)

When the coefficient of contact friction between the sliding contact surface 19 and the inner contact piece 22 is μ, the frictional force Pf, which is the product of the pressing force q and the friction coefficient μ, is Pf = μ · q = μ · P • sin α (2). The rotational torque T required as the rotational force about the axis due to the frictional force Pf is T = Pf · 2πrb · r = 2πbr ² μ · P · sinα (3), and the required rotational torque T is approximately proportional to the pressure difference P. Will be done.

[0021]

According to the above-mentioned conventional annular seal, the device 1 is 1 atm (1 atm) of the standard atmospheric pressure on the ground.
The air pressure inside the device adjusted and set in the state of m) is
As the altitude rises, a pressure difference occurs due to a decrease in the external atmospheric pressure, and the pressure on the sliding contact surface of the annular seal fluctuates step by step due to the internal pressure exerted on the annular seal that shields the inside and outside. Accordingly, the rotational torque for controlling the device is increased / decreased.

In contrast to the above-mentioned problems of the conventional annular seal, the present invention uses a two-stage V-shaped annular seal to prevent foreign matter from entering the rotary seal portion of the apparatus from the outside, assembly error, atmospheric pressure fluctuation, etc. It is an object of the present invention to provide an annular seal capable of adjusting the change of the rotational torque based on the above and setting the pressing contact force to the sliding contact surface to the optimum contact force.

[0023]

The object of the present invention to solve the above-mentioned problems is to provide an annular contact piece that elastically contacts the sliding contact surface and a pressing force of the annular contact piece against the sliding contact surface. Is an annular seal including an annular fluid accommodating portion that can be set by the fluid pressure of the fluid flowing inside, and a preferable mode of the fluid is gas. Further, the annular seal includes one having a fluid pressure variable supply means capable of variably adjusting the fluid pressure according to the external pressure.

[0024]

According to the above-mentioned constitutional means of the present invention, the pressing force of the annular contact piece against the sliding contact surface can be adjusted to an arbitrary pressing force by variably adjusting the fluid inflow pressure into the fluid containing portion.

Fine pressure adjustment can be performed by using an arbitrary gas as the fluid. Air is generally used as this gas, but an appropriate gas can be applied depending on the situation. If necessary, a fluid such as an oily liquid can be applied.

Since the fluid pressure variable supply means for supplying the fluid to the fluid container can be variably adjusted according to the external pressure, the pressing force can be automatically set within the predetermined range in accordance with the pressure difference. it can.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The annular seal of the present invention will be described in detail below with reference to the drawings based on an embodiment based on the constituting means. The same parts are denoted by the same reference symbols throughout the drawings.

FIG. 1 shows an infrared detector 31 according to the present invention.
FIG. 3 is a front view cross-sectional view of the device 31. The device 31 is mounted on an aircraft, for example. Similar to the above-described device, it is a schematic view of only a main part of which detailed details are omitted, and oblique lines showing a cross section are also omitted because the drawing is complicated.

It has a gimbal device for biaxial control of an X-axis 2 in the left-right direction in the drawing and a Z-axis 3 in the front and front directions in the drawing. It is rotated by the servo control signal of.

The following portions supported by the bearings 6 and 7 of the mounting base 5 with the Z axis 3 as the vertical direction are rotated about the Z axis 3 in the horizontal direction, and the main body section with the X axis 2 as the horizontal direction. The main body 8 supported by bearings 13 and 14 on the side of the support arm 12 that supports both shafts 9 and 11 of 8 is rotated about the X axis 2 in the depression direction. 8 can always be oriented in the desired direction.

The device 31 is mounted and mounted in a predetermined position of an aircraft or the like, but is exposed so as to come into contact with the external environment in a state of being exposed to the outside of the gas. Therefore, in order to prevent foreign matter such as moisture, moisture, and dust from entering the bearings 6, 7, 13, 14 and the inner side thereof from the external environment, annular seals 32, 3 are provided around the outer side.
Place 3, 34.

FIG. 2 shows a state in which the annular seals 32, 33, 34 are enlarged and the principle cross-sectional view is shown. FIG. 2 typically shows a part of the annular seal 32 which is a rotating part of the base part 5 and the support arm 12, and this part will be described.
It should be understood that the other parts are basically the same. This support arm 12 is attached to the base 5 via a bearing 6
It is rotatably supported around the shaft 3.

Support arm 12 facing the sliding surface 19 of the base portion 5.
An annular groove 35 is formed on the peripheral surface of the, and the annular seal 32 is fitted therein. V-shaped annular contact pieces 36 and 37 are integrally formed on the upper surface of the annular seal 32, and the tip end thereof is elastically contacted with the sliding contact surface 19.

The main body portion fitted into the concave groove 35 of the annular seal 32 is an annular fluid storage portion 38 made of a tube into which the fluid flows. The fluid container 38 is connected to a supply tube 41 extending downward and connecting to the fluid supply means 39. The annular seal 32 is made of synthetic rubber.

Annular contact pieces 36, 3 that contact the sliding contact surface 19
The tip end of 7 reliably prevents foreign matter from entering due to the initial value that is pressed by the restoring force against the pressing force pressed by the sliding contact surface 19 by a predetermined amount.

The fluid supply means 39 is, for example, a pump for fluid, and can arbitrarily adjust the fluid pressure in the fluid container 38. This will be described with reference to the partially enlarged view of FIG. 3. In FIG. 3A, the atmospheric pressure P ₁ on the inner side A and the atmospheric pressure P ₂ on the outer side B are both 1 atmospheric pressure, and The case where the pressure in the housing portion 38 is also in the same state is shown. That is, in a balanced state, the annular contact pieces 36, 37 are in contact with the sliding contact surface 19 with an initial pressing force.

The state shown in FIG. 3 (b) is in the fluid container 3
It is shown that the fluid pressure inside 8 is lower than the external pressure P _{1 and} the height of the fluid storage portion 38 becomes low and the fluid storage portion 38 has entered the inside of the groove 35.

The annular contact pieces 36, 37 are raised, and the V-shaped opening 42 formed therebetween is closed. This state is due to the elastic restoring force of the annular contact pieces 36 and 37, and the contact force to the sliding contact surface 19 is reduced.

The state shown in FIG. 3C is in the fluid container 3
It is shown that the fluid pressure inside 8 is higher than the external pressure P _{1 and} the height of the fluid storage portion 38 is higher than the surface of the groove 35.

The annular contact pieces 36, 37 are pressed against the sliding contact surface 19 so that the V-shaped opening 42 formed therebetween is opened. In this state, the elastic restoring force by the annular contact pieces 36, 37 is increased, and the contact force on the sliding contact surface 19 is increased.

The state shown in FIG. 3D is shown in FIG.
The pressure P on the inner side A is shown here.₁
Against the outside air pressure P₂Lowered, i.e.
Chi P ₁> P₂If it becomes, the annular contact piece on the inner side A
36 is pressed in the direction of the outer side B as shown by the chain double-dashed line.
As a result, the pressing contact force with respect to the sliding contact surface 19 increases.
It This is the same as described above with reference to FIG.
Something like that.

The annular contact piece 37 on the outer side B is pulled toward the outer side B by the pressure difference between the initial pressure P ₁ of the V-shaped space opening 42 and the atmospheric pressure P ₂ on the outer side B. The elastic restoring force of the piece 37 itself makes contact with the sliding contact surface 19,
Due to the decrease in the pressing force due to the pressure difference, the contact pressing force naturally decreases.

However, when the atmospheric pressure P ₂ decreases more than the restoring force of contacting the sliding contact surface 19, the air in the space 42 leaks between the contact with the sliding contact surface 19 and restores the state in which the restoring force is balanced. . In this state, P ₁ > P ₃ > P ₂ when the atmospheric pressure in the space 42 is P ₃ .

As shown in FIG. 2, the radius between the Z-axis 3 and the center of the sliding contact point of the annular seal 32 on the sliding contact surface 19 is r,
The width of the fluid containing portion 38 is d, the height of the fluid containing portion 38 is h,
Let δx be the amount of change in height of the annular contact pieces 36, 37, and let δ
FIG. 4 shows data obtained by the model experiment of the rotation torque T with respect to the change of x.

In FIG. 4, the abscissa represents δx at intervals of 0.1 mm, and the ordinate represents values obtained as rotational torque kg · f-cm. That is, the rotational torque of the value based on the annular seal 32 is set to 0, and δx is set to 0.1, 0.3, 0.
The fluid accommodating portion 38 is increased by 5, 0.8, 0.9 mm.
This is obtained when the fluid pressure inside is increased.

The model used is r = 75 mm, d = 1.
0 mm, h = 5 mm, and each δx
The experimental values obtained a plurality of times at the above points are within the range indicated by the arrows, and the curve 43 that averages between the respective arrows is obtained.

That is, as the amount of change δx due to the increase in fluid pressure increases, the frictional force increases, and the rotational torque T increases. This also means that the rotational torque T decreases when the fluid pressure is reduced from the reference state.

Referring to FIG. 5, FIG. 5 (a) shows the altitude H on the horizontal axis and the atmospheric pressure p ₂ corresponding to the altitude on the vertical axis. As the altitude H increases, the atmospheric pressure p ₂ changes as shown by the curve 44. It shows that it decreases.

In FIG. 6B, the horizontal axis shows the atmospheric pressure difference p inside and outside the apparatus, and the vertical axis shows the change of the rotational torque T with the atmospheric pressure difference p.
It is shown that the rotational torque T increases as shown by the curve 45 as the atmospheric pressure difference p increases.

FIG. 6C shows δx on the horizontal axis and changes in the rotational torque T on the vertical axis, and shows that the rotational torque T increases as the curve 43 increases with an increase in δx. This is the same as described in FIG.

From the above, assuming that the horizontal axis represents the atmospheric pressure difference p and the vertical axis represents δx as shown in FIG. 5D, δx increases as the atmospheric pressure difference p increases as shown by the curve 46. It turns out that it is necessary to reduce the required amount to reduce the rotational torque T and suppress the increase in the rotational torque due to the annular seal.

Referring to FIG. 6, the relationship with the fluid pressure variable supply means will be specifically described with reference to the principle schematic diagram of FIG. The outer diameter of the fluid storage portion 38 of the annular seal 32 is D ₁ , the inner diameter is D ₂ , and its height is h.

The effective inner diameter of the fluid pressure variable supply means 39 made of a bellows is D ₃ , and the length is Y. In addition, the dimensional change in the diameter direction of the annular seal 32 is restricted by the concave groove 35 and does not change, and the change amount only in the height h direction is δh. Also in the fluid pressure variable supply means 39, there is no change in the effective inner diameter D ₃ , and the amount of change in the length Y direction is δy.

From the above relationship, π / 4 · (D ₁ ² −D ₂ ² ) δh = π / 4 · D ₃ ² · δy (4) For example, the outer diameter D ₁ of the fluid containing portion 38 of the annular seal 32 is = 160 mmφ inner diameter D ₂ = 140 mmφ effective inner diameter of the fluid pressure variable supply means 39 If D ₃ = 20 mmφ, then from equation (4), 15δh = δy. Therefore, in order to increase δh by 0.5 mm, if the volume change due to the change in the fluid pressure is not considered, the connecting rod 4 of the fluid pressure variable supply means 39 is simply used.
8 is pushed in to set the length Y of the fluid pressure variable supply means 39 to 7.
It should be compressed by 5 mm.

That is, this 7.5 mm is the compression amount δy in this case. Here, the amount of change represented by δh is determined by comparing the annular contact pieces 36 and 37 of the annular seal 32 with the sliding contact surface 1.
It corresponds to the change amount δx of the height of the annular contact piece that is brought into pressure contact with 9. That is, an increase in the height change amount δh results in an increase in the δx amount, and a decrease in δh results in δx.
The amount will decrease.

Therefore, in order to reduce the increase of the rotational torque T due to the increase of δx due to the decrease of the external pressure, it is possible to reduce the height h of the annular fluid accommodating portion 38 by a required amount in order to reduce δh. It is a thing.

On the contrary, when the external air pressure rises to approach the internal pressure and the sealing function is likely to deteriorate, or when it becomes necessary to adjust the rotational torque to the standard state, the annular fluid storage is increased to increase δh. This can be achieved by increasing the height h of the portion 38 by a required amount.

The fluid pressure variable supply means 39 shown in FIG. 6B is a plunger type pump or a piston type pump, and the fluid pressure to the annular seal 32 can be increased or decreased by moving the connecting rod 48 forward or backward. it can. This effective inner diameter D ₃
Is the inner diameter of the cylinder 49 itself. Reference numeral 51 is an O-ring for sealing that contacts the inner surface of the cylinder 49.

The mounting state of the fluid pressure variable supply means 39 on the apparatus will be described with reference to FIG. 1. The annular seal 33 of the X-axis 2 of the apparatus 31 is indicated by the reference numeral 55 on the support arm 12. Attach it in place, and use tube 56 to make an annular seal 3.
Connect with 3.

Similarly, with respect to the annular seal 34, it is attached to the portion of the support arm 12 at a portion indicated by reference numeral 57, and is connected to the annular seal 34 by the tube 58. Z of device 31
The annular seal 32 of the shaft 3 is attached to a portion of the support arm 12 at a position indicated by reference numeral 59, and is connected to the annular seal 32 by a tube 61.

Second and third embodiments of the annular seal of the present invention will be described with reference to FIG. FIG. 7 (a) is the second
It is a principal part sectional view of the annular seal 32-2 of an Example, and the part of the annular contact pieces 36 and 37 and the annular fluid accommodating part 38 are manufactured as a separate body, respectively, and are integrally joined and formed. . According to such a manufacturing method, manufacturing is relatively easy, and each of them can be combined with those having different performances according to requirements.

FIG. 9B shows an annular seal 32-of the third embodiment.
3 is a cross-sectional view of an essential part of FIG. 3, in which an extended portion of the fluid storage portion 38 is also formed inside the annular contact pieces 36, 37. By doing so, when the fluid is pressurized in the fluid containing portion 38, the action of opening the interval between the tips of the annular contact pieces 36, 37 and the action of pushing up the whole are generated, so the contact force is reduced. When the pressure is reduced, the tip interval is closed to increase the contact force, and the action is to lower the whole, and the friction force can be adjusted in each case.

The fourth and fifth embodiments of the annular seal of the present invention will be described with reference to FIG. FIG. 8 (a) is the fourth
It is a principal part sectional drawing of the annular seal 32-4 of an Example, while opening the lower part of the fluid accommodating part 38, the fluid accommodating part 3 is shown.
Sealing pieces 65 and 66 are formed on the inner and outer circumferences of 8, and these sealing pieces 65 and 66 are slidably fitted into the peripheral wall surface of the recessed groove 35.

By doing so, it becomes possible to use the concave groove 35 as a fluid accommodating portion, and the annular seal 32-4 can be easily manufactured. Since the width of the groove 35 can be effectively used, the pressing force can be increased.

FIG. 9B shows an annular seal 32-of the fifth embodiment.
5 is a cross-sectional view of a main part of FIG.
5 and 66 are formed, and these sealing pieces 65 and 66 are formed into the groove 3
It is slidably attached to the surrounding wall surface of 5.

An annular metal concave metal fitting 67 is integrally embedded and molded on the inner surface of the fluid containing portion 38. By doing so, it becomes possible to use the concave groove 35 as a fluid accommodating portion, and the volume of the fluid accommodating portion 38 can be increased by the reinforcing effect of the metal concave metal fitting 67. Similarly, the width of the groove 35 can be effectively used.

Regarding the pressurization and depressurization of the fluid in the fluid storage portion of the annular seal according to the present invention, when the altitude changes, altitude information, for example, the differential pressure from the external pressure is obtained from the signal from the altimeter, or the mutual pressure is calculated. By obtaining the pressure difference with a pressure gauge and automatically controlling the pressurization and depressurization to the optimum state, it is possible to obtain a state in which there is no fluctuation in the rotational torque.

Of course, it is also possible to compensate for changes in pressure due to changes in temperature, and it is possible to control by making preset settings. Besides such control means,
It is also possible to obtain the variation amount from the relationship between the change amount of the drive current value of the torque motor for drive control by comparing with the reference current value and the pressure signal and perform the setting control in the optimum state.

As for the fluid, air can be used in general, but inert nitrogen gas or other suitable gas can be used, but the volume changes with pressure and temperature changes. It is also possible to utilize a fluid that does not exist, for example an oily liquid, such as silicone oil.

Although the embodiment of the present invention has been described by exemplifying the apparatus for mounting on an aircraft, the present invention is not limited to such an apparatus and is arbitrarily applied to an apparatus required to be set in an optimum state. It goes without saying that it is possible.

[0071]

As described in detail above, according to the annular seal of the present invention, the annular contact piece elastically contacting the sliding contact surface and the pressing force of the annular contact piece against the sliding contact surface are made to flow by the fluid pressure. Since it comprises a ring-shaped fluid accommodating portion that can be set, the practical effect of arbitrarily setting the pressing contact force to the sliding contact surface to the optimum contact force according to various state changes is extremely remarkable. .

Although the gas is the easiest to handle as a fluid, it is not limited to such a gas, and a liquid having a small volume change or a viscous liquid can be applied. The fact that the fluid pressure can be automatically adjusted in combination with the fluid pressure variable supply means capable of variably adjusting the fluid pressure according to the external pressure has further practical effects, and the control means can be maintained in a stable state. You can

[Brief description of drawings]

FIG. 1 is a front sectional view of an infrared detection device according to the present invention.

FIG. 2 is a sectional view showing the principle of the present invention annular seal.

[Fig. 3] Contact state due to pressure change

FIG. 4 shows the relationship between the amount of change in the height of the annular contact piece and the rotational torque.

[Fig. 5] Relationship between the amount of change in height of the annular contact piece and the pressure difference

FIG. 6 shows the relationship between the annular seal and the fluid pressure variable supply means.

FIG. 7: Second and third embodiments of annular seal

FIG. 8 is a fourth and fifth embodiment of the annular seal.

FIG. 9 is a front sectional view of the infrared detection device.

10 is a partial cross-sectional view of the annular seal portion in FIG.

FIG. 11 is a schematic view of an annular seal.

[Explanation of symbols]

 2 X-axis 3 Y-axis 5 Base 6,7 Bearing 8 Main body 9,11 Bearing 12 Support arm 13,14 Bearing 19 Sliding contact surface 31 Infrared detector 32,33,34 Annular seal 35 Recessed groove 36,37 Annular contact piece 38 Fluid accommodation part 39 Fluid supply means, fluid pressure variable supply means 41 Supply tube 42 Opening, space 43,44,45,46 Curve 48 Connection rod 49 Cylinder 51 O-ring 55,57,59 Fluid pressure variable supply means 56,58 , 61 Tube 65, 66 Seal piece 67 Metal concave metal fitting

Claims (3)

[Claims] 1. An annular contact piece elastically contacting the sliding contact surface, and an annular fluid accommodating portion capable of setting the pressing force of the annular contact piece against the sliding contact surface by the fluid pressure flowing therein. Characteristic annular seal. 2. The annular seal according to claim 1, wherein the fluid is a gas. 3. The annular seal according to claim 1, further comprising a fluid pressure variable supply means capable of variably adjusting the fluid pressure according to an external pressure.