JPH0799207B2 - Unidirectional shaft seal device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention is interposed between a casing such as various actuators including a shaft and a casing, and an outer peripheral surface of the shaft, The present invention relates to a unidirectional shaft seal device which allows a fluid flow between two spaces only in one direction.

<Prior Art> Conventionally, in an engine that performs a rotary motion or a reciprocating motion, a so-called shaft that seals between a shaft performing the motion and a casing in which the shaft is inserted for the purpose of dustproofing and waterproofing. For some, it is essential to have a sealing device.

For example, the bellows type and bellows type shown in Figs. 13 (a) and (b) are capable of complete shaft sealing, but have problems in durability and can only be used for reciprocating shaft movement. is there.

The mechanical seal shown in FIG. 13 (c) is composed of a driven ring 91 that moves in the direction of the axis 93 and a seat ring 92 that does not move according to the wear of the sealing end surface, and the mechanical seal has little leakage. The seal is effective only for the rotating shaft and cannot be used for the reciprocating motion of the shaft 93.

Here, there is a gland packing 94 shown in FIG. 13 (d) which can be used for the reciprocating motion and the rotating motion of the shaft.
There is a problem in the durability of the gland packing 94 itself. Therefore, there is an oil seal shown in FIG. 13 (e) that is usable for reciprocating motion and rotating motion of the shaft, has excellent sealing property, and has durability.

<Problems to be Solved by the Invention> By the way, since the oil seal is made of rubber, it is necessary to always be in sliding contact with the shaft in order to ensure the above-mentioned sealing performance. For this reason, a large frictional force always acts between the shaft and the oil seal, and when mounted on an engine, high output cannot be obtained due to an increase in wear loss.

With regard to the shaft seal device, dust from the outside is prevented from entering the engine, lubricating oil inside the engine is prevented from flowing out, and the flow of the fluid to be sealed is unidirectional. In many cases, it is not necessary to always use a large frictional force to seal the shaft in the various pumps, actuators, etc. that include a shaft and a casing, that is, between the two spaces. If it is configured so that the fluid flow can be reliably and hermetically sealed in only one direction, it can sufficiently function as a shaft seal device.

The present invention has been made in view of such a conventional situation, and a structure of a shaft seal device interposed between a casing in which a shaft is fitted so as to freely move inside thereof and the shaft. By improving the above, the configuration based on a completely new idea of having a valve function of positively inflowing the working fluid in the opposite direction while suppressing leakage of the working fluid in one direction as much as possible, It is an object of the present invention to provide a unidirectional shaft seal device that solves various problems.

<Means for Solving the Problem> Therefore, the present invention provides a unidirectional shaft seal device which is interposed between the inner peripheral surface of the casing and the outer peripheral surface of the shaft fitted in the casing. And a seal ring which is inserted into and held by a peripheral groove formed on the peripheral surface of one of the two members formed of the casing and the shaft so as to freely move in the axial direction, and which is in sliding contact with the peripheral surface of the other member. A communication passage that is mounted between the seal ring and the bottom of the circumferential groove and that communicates between the inner space of the bottom of the circumferential groove and the outside of the circumferential groove between one circumferential side surface and one circumferential side surface of the circumferential groove. And an elastic ring whose other peripheral side surface is in pressure contact with the other peripheral side surface of the peripheral groove, and a seal ring is mounted between the elastic ring and the peripheral groove bottom portion via the elastic ring to form the other member. A tension ring that has a spring property and is pressed against the peripheral surface of the The elastic ring separates the inner space and the outside of the bottom portion of the circumferential groove from each other and communicates the two through the communication passage.

In addition, the seal ring may include a plurality of ring members each having an abutment part in which a part of the ring is removed, and the seal rings may be mounted by overlapping in an axial direction so that the abutment parts of the ring members do not overlap each other.

Further, the elastic ring may be formed with a width larger than the groove width of the circumferential groove, and the communication passage may be formed by forming notches on the one circumferential side surface in a distributed manner in the circumferential side surface direction.

Further, the elastic ring has a pressing means between the one peripheral side surface and one peripheral side surface of the peripheral groove, and the other peripheral side surface of the elastic ring is the other peripheral surface of the peripheral groove by the pressing force of the pressing means. It may be pressed against the side surface.

In addition, the seal ring may have a plurality of grooves radially formed on a peripheral side surface on the same side as the one peripheral side surface of the elastic ring.

In addition, one circumferential side surface of the circumferential groove may be radially formed with a plurality of circumferential grooves on the same circumferential side surface as the one circumferential side surface of the seal ring.

Further, it may be a spiral ring provided with a plurality of seal rings, and the seal ring on the same side as the one peripheral side surface is spirally wound around an axis.

Further, a rotation prevention device for preventing relative rotation between the seal ring and the casing may be provided.

Further, a plurality of sets of unidirectional shaft sealing devices may be stacked in the axial direction in a predetermined direction.

<Operation> The operation of the above configuration will be described, but the description will be divided into cases where the shaft (including piston and the like) reciprocates and cases where the shaft performs rotational motion. First, the operation when the shaft freely reciprocates inside and outside the casing will be described.

The pressure on the outside of one of the peripheral side surfaces of the peripheral groove (hereinafter referred to as one of the outside) that forms a communication path that communicates the internal space of the peripheral groove bottom with the outside is equal to that of the other peripheral side surface of the peripheral groove. When the pressure is relatively higher than the pressure at the outside (hereinafter referred to as the other outside), the seal ring moves in the circumferential groove to the other circumferential side surface opposite to the side forming the communication passage, It abuts on the other peripheral side surface.

As a result, a communication passage that communicates the inner space of the bottom of the circumferential groove with the outside of the one side is opened in the gap between the one circumferential side surface of the seal ring and the one circumferential side surface of the circumferential groove, and the fluid existing outside the one side is opened. Enters between the tension ring and the circumferential groove through the communication passage and presses the tension ring against the abutment surface of the seal ring, and the sliding of the other member through which the circumferential ring is not formed on the seal ring through the tension ring. It acts to strengthen the force that is applied to the contact surface.

Further, since the elastic ring has a configuration in which the other peripheral side surface is in pressure contact with the other peripheral side surface of the peripheral groove, the other peripheral side surface is
The entire circumference is pressed against the other circumferential side surface of the circumferential groove with elastic force.

In this way, the contact surfaces of the elastic ring and the seal ring are strongly pressed against each other, the seal ring and the other member are also strongly slidably contacted, and the other peripheral side surface of the elastic ring is the peripheral groove. Since the sealability of each part is improved by being pressed against the other side surface of the other side, it is possible to effectively prevent the fluid existing outside the one side from leaking to the outside of the other side.

On the other hand, when the pressure on the other side becomes relatively higher than the pressure on the other side, the seal ring moves to the side forming the communication passage in the circumferential groove and abuts on the one side surface. .

As a result, the fluid existing outside the other side enters through the gap formed between the seal ring and the peripheral groove, and the gap formed on the pressure contact surface between the seal ring and the elastic ring and the pressure contact between the seal ring and the peripheral groove. It flows out to the outside of the one through the gap formed in the surface and the gap in the sliding contact surface between the seal ring and the other member, so that the pressures of both outsides are equalized. In addition, the fluid flow between the two exteriors is facilitated.

Further, when the seal ring is provided with a plurality of ring members and is mounted by overlapping in the axial direction so that the abutments of the ring members do not overlap with each other, the seal ring moves to the other circumferential side surface side of the circumferential groove. In this case, the leakage of fluid from the abutment can be suppressed because the abutments are mounted so that they do not overlap each other. The fluid flows out to the outside.

Further, when the notches are formed in a distributed manner on the one circumferential side surface of the elastic ring in the circumferential side surface direction, a communication passage that communicates the internal space of the circumferential groove bottom portion with the outside is formed by this.
In addition to exerting the same effect as described above, when the width of the elastic ring is formed to be larger than the groove width of the peripheral groove, the elastic ring is elastically deformed, and the other peripheral side surface of the elastic ring is the entire circumference. It is pressed against the other circumferential side surface of the circumferential groove with elastic force.

Further, by providing a pressing means between the one circumferential side surface of the elastic ring and the one circumferential side surface of the circumferential groove,
The other peripheral side surface of the peripheral groove is pressed by the pressing force of the pressing means.

Further, when a plurality of grooves are radially formed on the same peripheral side surface as the one peripheral side surface of the elastic ring of the seal ring, the one external fluid flows through the groove to the tension ring through the communication passage. When the pressure on the outside of the one side is high, the force for pressing the tension ring against the seal ring and the force for pressing the seal ring against the other member via the tension ring become easy. As a result, the fluid leakage prevention function is increased.

Also, when a plurality of grooves are radially formed on the same circumferential side surface as the one circumferential side surface of the circumferential groove, the one external fluid is passed through the groove to the tension ring and the circumferential groove through the communication passage. When the pressure on the one side is high, the force of pressing the tension ring against the seal ring and the force of pressing the seal ring against the other member via the tension ring increase. , The fluid leakage prevention function is increased.

Further, when a plurality of seal rings are provided, and the seal ring on the same side as the one peripheral side surface is a spiral ring spirally wound around the shaft, the one side is provided through the overlapping groove of the spiral ring. When the external pressure of the one side is high pressure, the fluid outside of the one easily enters between the tension ring and the circumferential groove through the communication passage, and the force for pressing the tension ring against the seal ring and the tension ring are used. , The force of pressing the seal ring against the other member increases, and the function of suppressing the outflow and leakage of fluid increases.

Further, by overlapping the unidirectional shaft seal device in the axial direction in the same direction on one of the peripheral side surfaces described above, the seal rings can be pressed in multiple steps against the outer peripheral surface of the shaft. The pressing force is increased, and the function of suppressing the outflow and leakage of fluid is further increased. When the one-way shaft seal device is axially overlapped with the one circumferential side surface facing each other, it has a function of suppressing the outflow and leakage of fluid from both sides, and thus has no directivity. It can be a shaft seal device.

Next, the operation of the unidirectional shaft seal device when the shaft freely rotates will be described.

In this case, since the elastic ring is in pressure contact with the circumferential groove and the seal ring, the circumferential groove, the elastic ring and the seal ring are relatively fixed, and the seal ring and the other member come into contact with each other. The surfaces are in sliding contact with each other. And
Similar to the case where the shaft reciprocates as described above, the actions associated with the respective configurations have similar actions, but the description thereof is omitted here.

Further, when a rotation prevention device for preventing relative rotation between the seal ring and the casing is provided as a configuration adapted to the rotational movement, the relative rotation between the seal ring and the circumferential side surface of the circumferential groove is reliably fixed. It will be. Therefore, wear due to friction due to rotation can be prevented at the pressure contact surface between the one peripheral side surface of the elastic ring and the one peripheral side surface of the peripheral groove and the pressure contact surface between the outer peripheral surface of the seal ring and the inner peripheral surface of the elastic ring. . Therefore, a seal is formed while rotating only on the sliding contact surface between the seal ring and the other member, and as in the case of the reciprocating motion described above, the fluid due to the increase in the pressing force of the seal ring against the other member is used. Leakage control,
And there is a fluid flow between the two exteriors which equalizes the pressures of the two exteriors.

<Example> Below, the Example of this invention is described based on drawing.

The first embodiment shown in FIG. 1 is an application of the unidirectional shaft sealing device according to the present invention to an actuator, and a casing 2 in which a shaft (output shaft of the actuator) 1 is inserted so as to freely reciprocate. The unidirectional shaft seal device is interposed between the peripheral groove 2a formed at the end of the shaft and the outer peripheral surface of the shaft 1.

In the figure, on the side closer to the inside of the actuator, the inner peripheral surface is in sliding contact with the outer peripheral surface of the shaft 1, and a ring made of steel or the like having an abutment 3a with a part of the ring shown in FIG. 2 cut away. A pair of seal rings 3 made of members are overlapped in the axial direction so that the respective mating openings 3a do not overlap with each other, and are fitted and held in the circumferential groove 2a so as to be freely movable in the axial direction.

The outer circumference of the pair of seal rings 3 has a width slightly larger than the groove width of the peripheral groove 2a, and is circumferentially interrupted on one peripheral side surface which is the inner side (left side in FIG. 1) of the actuator. An elastic ring 4 made of rubber or a material having rubber-like elasticity as shown in FIG. Thereby, the elastic ring 4
The inner space at the bottom of the peripheral groove 2a and the outside of the peripheral groove are separated from each other as a boundary, and both are communicated with each other through the notch 4a as a communication passage.

As a material for forming the elastic ring 4, natural rubber, styrene butadiene rubber, butyl rubber, ethylene propylene rubber, chloroprene rubber, nitrile rubber, urethane rubber,
There are shrimp chlorohydrin rubber, acrylic rubber, silicone rubber, fluororubber, tetrafluoroethylene resin, etc., and an appropriate one may be selected according to operating conditions. For example, when considering heat resistance, silicone rubber or the like may be used, and when not considering, natural rubber or the like may be used.

On the outer circumference of the elastic ring 4, a tension ring 5 made of spring steel or the like having a spring property for pressing the seal ring 3 against the outer peripheral surface of the shaft 1 via the elastic ring 4 is mounted.
The tension ring 5 also has a shape in which a part of the ring is cut at the joint.

Next, the operation of this embodiment will be described.

FIG. 4 (a) shows a state in which work is performed by the actuator, and the pressure Pc in the inner space C of the actuator is higher than the pressure Pe in the outer space E of the actuator (Pc> Pe). . In this case, the pressure Pc causes the pair of seal rings 3 to move in the circumferential groove 2a in the direction opposite to the cutout 4a, and the other circumferential side surface opposite to the cutout 4a.
Abut on 21a.

At this time, the fluid in the space C passes through the gap 11 between the seal ring 3 and the circumferential groove 2a, further passes through the notch 4a of the elastic ring 4, and the pressure on the outer circumference of the seal ring 3 is reduced by the pressure drop.
It becomes a fluid of Pc 'and acts as a force for compressing and closing the seal ring 3 in the radial direction. As a result, the inner peripheral surface of the elastic ring 4 comes into pressure contact with the outer peripheral surface of the seal ring 3 with a strong force, and the inner peripheral surface of the seal ring 3 comes into sliding contact with the outer peripheral surface of the shaft 1 with a strong force. With a pneumatic actuator, for example, air as a working fluid can be almost completely prevented from leaking from the sliding contact surface 7.

Further, since the elastic ring 4 has a width slightly larger than the groove width of the peripheral groove 2a, the other peripheral side surface of the elastic ring 4 is the other peripheral side surface 21a of the peripheral groove 2a over the entire circumference.
Since they are pressed against each other with elastic force, leakage of the working fluid from the pressed surface 62 can be almost completely prevented.

FIG. 4 (b) shows a state in which the work by the actuator is completed, and the volume of the fluid discharged when the above-mentioned work is performed in the space C is expanded and the pressure Pc of the space C is increased. The state when the pressure becomes low (Pc <Pe) with respect to the pressure Pe of E is shown.

In this case, this pressure Pe is due to the pair of seal rings 3 and the circumferential groove.
The tension ring acts on the inner peripheral surface 8 of the elastic ring 4 opposite to the side where the notch 4a is formed from the gap 13 with the 2a, and acts as a surface pressure for enlarging the diameters of the elastic ring 4 and the tension ring 5. Seal ring 3 overcoming the spring force of 5
And a gap is generated on the pressure contact surface 61 between the elastic ring 4 and the elastic ring 4, and the space E
The working fluid easily flows from the space C to the space C. Further, since a gap is created in the pressure contact surface 61, the pressing force on the sliding contact surface 7 between the seal ring 3 and the shaft 1 is also reduced, and thus the pressure Pe acting on the peripheral side surface 10 of the seal ring 3 causes the seal ring 3 to rotate. The groove 2a is moved to the notch 4a side and abuts on one peripheral side surface 22a of the peripheral groove 2a.

As a result, the working fluid comes into contact with the seal ring 3 and the peripheral groove 2a from the gap 13 formed between the seal ring 3 and the peripheral groove 2a on the pressure contact surface 61 between the seal ring 3 and the elastic ring 4. The pressure in both spaces C and E is passed through the gap 12 formed in the contact surface and further through the gap formed in the sliding contact surface 7 between the inner peripheral surface of the seal ring 3 and the outer peripheral surface of the shaft 1. To be equalized, the gas flows out from the space E to the space C by an amount corresponding to the difference between the pressure Pe and the pressure Pc.

In this way, the working fluid flows into the space C during the stroke when the work is not performed, so as to supplement the leaked working fluid when the work is performed by the actuator, thereby improving the efficiency of the next work. In addition, since the pressure can be increased without leakage of the working fluid in the work process, the overall efficiency of the actuator can be improved.

FIG. 5 shows a second embodiment of the unidirectional shaft seal device according to the present invention. In this embodiment, the same components as those in the first embodiment described above are designated by the same reference numerals and the description thereof will be omitted.

As the structure according to the second embodiment, an inner ring 41 made of ethylene tetrafluoride resin or the like is mounted on the outer circumference of the pair of seal rings 3. The inner ring
41 has a width slightly smaller than the groove width of the peripheral groove 2a, and a plurality of springs 42 as pressing means are provided on the peripheral side surface on the inner side (left side in FIG. 5) of the actuator. .

Next, the operation of this embodiment will be described.

In the inner ring 41, a plurality of springs 42 are provided on the inner side of the actuator, and the gap between the springs 42 functions similar to the notch 4a in the first embodiment.

Further, the inner ring 41 is pressed by the pressing force of the spring 42 from the pressure contact surface 62 because the peripheral side surface on the side opposite to the spring 42 side is elastically pressed against the peripheral side surface 21a of the peripheral groove 2a over the entire circumference. The leakage of the working fluid can be almost completely prevented.

Therefore, when working with an actuator,
The inner peripheral surface of the inner ring 41 presses against the outer peripheral surface of the seal ring 3 with a strong force, and the inner peripheral surface of the seal ring 3 slides against the outer peripheral surface of the shaft 1 with a strong force. Leakage of the working fluid from 7 can be prevented almost completely.

Further, when the work by the actuator is completed, the flow of the fluid between the two spaces C and E is equalized so that the pressures in both spaces C and E are equalized, as in the first embodiment. Done.

By the way, since the gap between the seal ring 3 and the circumferential groove 2a is as small as several tens of microns, the pressure drop Δ
P (= Pc-Pc ') becomes considerably large.

Therefore, as a third embodiment according to the present invention, as shown in FIG. 6, a plurality of grooves 3b are radially provided on one circumferential side surface of the seal ring 3, and in FIG. The seal ring 3 is mounted in the circumferential groove 2a so as to be formed on the circumferential side surface on the same side as the side where the notch 4a is formed.

In such an embodiment, when the actuator performs the work, the pressure Pc in the space C easily enters the clearance on the outer periphery of the tension ring 5 through the grooves 3b, so that the pressure drop decreases and the seal ring 3 The pressing force of the shaft 1 against the outer peripheral surface of the shaft 1 is further strengthened. Therefore, the function of suppressing the leakage of the working fluid from the space C is further enhanced, and the average working fluid pressure is further enhanced.

A fourth embodiment according to the present invention as shown in FIG. 7 and FIG. 8 has the same function and effect as the plurality of grooves 3b provided in the seal ring 3 in the third embodiment. As a result, a plurality of grooves 24a are radially provided on one circumferential side surface 22a of the circumferential groove 2a. Also in this embodiment, the same components as those in the first embodiment described above are designated by the same reference numerals and the description thereof will be omitted.

Also in this embodiment, when the actuator performs the work, the pressure Pc in the space C easily enters the clearance on the outer circumference of the tension ring 5 through the grooves 24a, so that the pressure drop decreases and the seal ring 3 The pressing force of the shaft 1 against the outer peripheral surface of the shaft 1 is further strengthened. Therefore, the function of suppressing the leakage of the working fluid from the space C is further enhanced, and the average working fluid pressure is further enhanced.

Further, in the fifth embodiment according to the present invention, in the case where a plurality of the seal rings 3 are provided as a structure exerting the same effect as the plurality of grooves 3b provided in the seal ring 3 in the third embodiment described above. At one peripheral side surface 22 of the peripheral groove 2a
Attach the seal ring on the same side as a to the shaft 1 as shown in Fig. 9.
Spiral ring 33 with multiple spiral windings around
I am trying.

Also in this embodiment, it is possible to shift the positions of the cut ends 33a at both ends, so that the same effect can be obtained.

FIG. 10 shows a sixth embodiment of the unidirectional shaft seal device according to the present invention. Also in this embodiment, the same components as those in the first embodiment described above are designated by the same reference numerals and the description thereof will be omitted.

As the configuration according to the sixth embodiment, a plurality of circumferential grooves 25, 26, 27 are formed on the inner wall of the casing 2 in which the shaft 1 is fitted so as to freely reciprocate inside thereof, and the respective circumferential grooves 25, 26, 27 are formed. For example, the unidirectional shaft sealing device is superposed on 26 and 27 in the same direction on the side where the notch 4a of the elastic ring 4 is formed.

According to such an embodiment, the seal rings 3 are pressed against the outer peripheral surface of the shaft 1 in multiple stages, and as a result, the pressing force increases and the fluid outflow / leakage suppression function further increases.

Further, FIG. 11 shows a seventh embodiment of the unidirectional shaft seal device according to the present invention. Also in this embodiment, the above-mentioned first
The same components as those in the embodiment are designated by the same reference numerals and the description thereof will be omitted.

In the structure according to the seventh embodiment, two peripheral grooves 28, 29 are formed in the inner wall of the casing 2 in which the shaft 1 is fitted so as to freely reciprocate inside thereof, and the respective peripheral grooves 28, 29 are formed. For example, the unidirectional shaft seal device is superposed on the notch 4a forming side of the elastic ring 4 described above in the direction of facing each other.

According to the present embodiment, the unidirectional shaft seal device relating to the circumferential groove 28 has the function of preventing the fluid from leaking from the space L to the space R when the pressures P _L and P _R are P _L > R _R. Playing and also the circumferential groove
The one-way shaft seal device according to 29 has an effect of preventing fluid leakage from the space R to the space L when P _L <P _R.

Therefore, the seal ring 3 and the elastic ring 4 exert the action of suppressing the outflow and leakage of fluids from both, and the shaft seal device having no directionality can be obtained.

In the first to seventh embodiments described above, the shaft is interposed between the outer peripheral surface of the shaft and the peripheral groove formed in the inner wall of the casing in which the shaft is freely reciprocated. The present invention relates to a unidirectional shaft sealing device, the unidirectional shaft sealing device according to the present invention is provided with a circumferential groove formed in a casing fitted so that the shaft rotationally moves, and an outer peripheral surface of the shaft. The same action and effect as described above can be obtained when it is interposed between and.

That is, as an eighth embodiment of the unidirectional shaft seal device according to the present invention when the shaft 1 makes a rotational movement, there is a structure as shown in FIG. Also in this embodiment, the same components as those in the first embodiment described above are designated by the same reference numerals and the description thereof will be omitted.

That is, the seal ring 3 has the configuration according to the present embodiment.
A rotation prevention pin 15 is provided as a rotation prevention device for preventing relative rotation between the casing 2 and the casing 2. The rotation prevention pin 15
Is fixed to the circumferential groove 2a and is a hole provided in the seal ring 3.
The seal ring 3 is fitted into the peripheral groove 2a and is prevented from rotating with respect to the peripheral groove 2a by the rotation preventing pin 15.
Move 2a left and right.

According to the configuration of this embodiment, the seal ring 3 and the circumferential groove 2a
Is fixed relative to the side surface relative to the direction of rotation. Therefore, the pressure-contact surface 61 between the seal ring 3 and the elastic ring 4 and the pressure-contact surface 62 between the peripheral edge portion 2a of the elastic ring 4 and the circumferential groove 2a can be prevented from being worn by friction due to relative rotation. Therefore, only the sliding surface 7 between the inner peripheral surface of the seal ring 3 and the outer peripheral surface of the shaft 1 provides a seal while reliably rotating. Therefore, similar to the case where the shaft reciprocates in the first embodiment and the like, the same actions as those associated with the respective configurations are performed (the description thereof is omitted here), and the outer periphery of the shaft 1 of the seal ring 3 is performed. The outflow and leakage of the fluid are suppressed by increasing the pressing force to the surface, and the fluid flows so as to equalize the pressures of both spaces. In the above-described embodiments, the peripheral groove is not provided on the shaft side, and only the peripheral groove is provided on the casing side into which the shaft is fitted. However, the peripheral groove may be provided on the shaft side. Good. For example, in FIG. 1, if 2 is replaced by a piston and 1 is replaced by a cylinder peripheral wall, a so-called piston ring is replaced with the unidirectional shaft seal device according to the present invention. The function of this is the same as that of FIG.

As described above, according to the unidirectional shaft seal device of the present invention, it is possible to incorporate the unidirectional shaft seal device into the conventional circumferential groove, and the directional property is obtained by simply changing the direction of the seal device. It is possible to change, and when adapted to a reciprocating engine, etc., it is possible to design by freely changing the ratio of characteristics for each stroke, so that, for example, near perfect airtightness can be obtained in the compression stroke, On the other hand, in the expansion stroke, friction with the shaft of the seal ring is reduced, and power consumption can be reduced.

<Effects of the Invention> As described above, according to the present invention, the unidirectionality interposed between the circumferential groove formed in one member of the shaft and the casing and the circumferential surface of the other member. The flow of fluid from one of the two spaces defined on both sides of the shaft seal device to the other is
Although it has a high sealing ability to prevent it, it is possible to improve the efficiency of the actuator etc. and reduce the driving power by adopting a structure that facilitates reverse flow, and the structure is simple. Therefore, in addition to cost reduction, it is possible to promote reduction of operation cost due to reduction of driving friction, quietness, and the like.

Further, it is not limited to the application to these actuators and the like, and can be applied to any place such as a shock absorber as long as it has a shaft and a casing and is required to have a sealing property, and its application is endless. It is something that is spread.

[Brief description of drawings]

FIG. 1 is a sectional view showing the structure of the first embodiment of the present invention, and FIG.
Fig. 3 is a perspective view of a seal ring according to the above embodiment, Fig. 3 is a perspective view of an elastic ring according to the above embodiment, and Fig. 4 (a) is a cross-sectional view showing a state of performing work according to the first embodiment. FIG. 5B is a sectional view showing a state when the work is not yet carried out, and FIG. 5 is a sectional view showing the constitution of the second embodiment of the present invention.
FIG. 6 (a) is a front view of a seal ring according to a third embodiment of the present invention, FIG. 6 (b) is a side view of the same, and FIG. 7 is a sectional view showing a configuration of a fourth embodiment of the present invention. FIG. 8 is a sectional view taken along the line AA in FIG. 7, FIG. 9 is a perspective view of a spiral ring according to a fifth embodiment of the present invention, and FIG. 10 shows the configuration of a sixth embodiment of the present invention. FIG. 11 is a sectional view showing a seventh embodiment of the present invention.
FIG. 12 is a sectional view showing the constitution of the embodiment, FIG. 12 is a sectional view showing the constitution of the eighth embodiment of the present invention, and FIGS. 13 (a) to 13 (e) are sectional views showing the constitution of a conventional shaft seal device. is there. 1 ... Shaft, 2 ... Casing, 2a, 25-29 ... Circumferential groove, 3
...... Seal ring, 3b, 24a ...... groove, 4 ...... elastic ring,
4a …… Notch, 5 …… Tension ring, 7 …… Sliding contact surface, 61,62 …… Pressing contact surface

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masahiro Matsuo 4-2-22 Kitamachi, Warabi-shi, Saitama (56) References Showa 58-84350 (JP, U)

Claims (9)

[Claims] 1. A unidirectional shaft seal device interposed between an inner peripheral surface of a casing and an outer peripheral surface of a shaft fitted into the casing, the two-member comprising the casing and the shaft. Of these, a seal ring which is inserted and held in a peripheral groove formed on the peripheral surface of one member so as to be freely movable in the axial direction and which is in sliding contact with the peripheral surface of the other member, the seal ring and the bottom of the peripheral groove. Is formed between one peripheral side surface of the peripheral groove and one peripheral side surface of the peripheral groove, and a communication passage that connects the internal space of the bottom of the peripheral groove and the outside of the peripheral groove is formed, and the other peripheral side surface is the peripheral groove. An elastic ring that is pressed against the other circumferential side surface of the elastic ring, and a spring-like tension that is mounted between the elastic ring and the bottom of the circumferential groove and presses the seal ring against the circumferential surface of the other member via the elastic ring. A ring, and the elastic ring A unidirectional shaft seal device, characterized in that an inner space and an outer part of the bottom of the circumferential groove are defined and are communicated with each other through the communication passage. 2. A plurality of ring members each having an abutment part in which a part of the seal ring is removed, and the abutment parts of the respective ring members are mounted so as to overlap each other in an axial direction so as not to overlap each other. The unidirectional shaft seal device according to claim 1. 3. The elastic ring is formed with a width larger than the groove width of the peripheral groove, and cutouts are formed on the one peripheral side surface in the peripheral side surface direction to form a communicating path. The unidirectional shaft seal device according to claim 1 or 2. 4. The elastic ring has a pressing means between the one peripheral side surface and one peripheral side surface of the peripheral groove, and the other peripheral side surface is formed by the pressing force of the pressing means. The one-way shaft seal device according to claim 1 or 2, which is pressed against the other peripheral side surface of the. 5. The seal ring according to claim 1, wherein a plurality of grooves are radially formed on a peripheral side surface on the same side as the one peripheral side surface of the elastic ring. One-way shaft seal device. 6. A plurality of grooves are radially formed on one peripheral side surface of the peripheral groove on the same peripheral side surface as one peripheral side surface of the seal ring. Unidirectional shaft seal device described in 1. 7. The one-way shaft seal according to claim 1, wherein a plurality of the seal rings are provided, and the seal ring on the same side as the one circumferential side surface is a spiral ring wound around a shaft in a spiral shape. apparatus. 8. A rotation preventing device for preventing relative rotation between the seal ring and the casing.
7. The unidirectional shaft seal device according to any one of 7. 9. The unidirectional shaft seal device according to claim 1, wherein a plurality of sets of the unidirectional shaft seal device are stacked in a predetermined direction in the axial direction.