JPH11159628A - Seal structure and seal method for fluid pressure actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a seal structure of a fluid pressure actuator whereby a seal life can be rapidly extended. SOLUTION: In this seal structure in a fluid pressure actuator 1, a plurality of seal packings 6, 7 are provided in a slide part of the fellow relatively moved two actuator constitutional members 2, 4. One of the seal packings 6, 7 serves as a main seal packing 6, and the rest of the packing serves as an auxiliary seal packing 7. A seal part 9 formed in an internal peripheral side of the main seal packing 6 is arranged in a condition coming into slide contact from the beginning relating to the actuator constitutional member 4. A seal part 9 formed in an internal peripheral side of the auxiliary seal packing 7 is arranged in a condition with slide contact impossible in the beginning and possible after the lapse of prescribed period relating to the actuator constitutional member 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing structure and a sealing method for a fluid pressure actuator.

[0002]

2. Description of the Related Art For example, in an air cylinder using air pressure, a part where the members constituting the air cylinder slide is sealed by some means to prevent air leakage from the sliding part. There is a need. Here, an example of a conventional seal structure is shown in FIG. A conventional technique of the same type is disclosed, for example, in JP-B-63-23426.
This is also disclosed in the official gazette.

According to the conventional sealing structure, a piston rod 73 is inserted into a housing 72 constituting an air cylinder 71. A piston (not shown) is provided at one end of the piston rod 73. And
The piston rod 73 is configured to protrude and retract from the housing 72 by supplying and discharging air to both chambers partitioned on both sides of the piston. A seal packing 75 is housed in a packing housing space 74 formed in the housing 72. The seal packing 75 is annular, and has two lip-shaped seal portions 76 and 77 on its inner peripheral side.
It has. As a result of the distal ends of these seal portions 76 and 77 being arranged so as to be in sliding contact with the outer peripheral surface of the rod, the sliding portion between the cylinder components that relatively move is sealed.

Further, with such a seal structure, wear is less likely to occur on the seal portions 76 and 77 as compared with a case where only one of the first-stage seal portion 76 and the second-stage seal portion 77 is provided. As a result, early reduction of the sealing force is also prevented. Therefore, air leakage from the sliding portion to the outside is prevented by extending the seal life somewhat, and the cylinder 7
It is considered that the durability of No. 1 leads to improvement.

[0005]

However, according to the above-mentioned prior art, the air in the state where the first-stage seal portion 76 and the second-stage seal portion 77 are brought into sliding contact with the outer peripheral surface of the rod from the beginning. The use of the cylinder 71 is started. Therefore, the two seal portions 76 and 77 are worn almost simultaneously, so that the sealing force is wasteful. For this reason, the seal life could not be increased significantly as expected.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a sealing structure and a sealing method of a fluid pressure actuator which can greatly extend a sealing life.

[0007]

According to a first aspect of the present invention, there is provided a seal structure in which a seal packing is provided at a sliding position between two relatively moving actuator components. A plurality of seal packings are provided in the sliding portion, one of the seal packings is used as a main seal packing, and the other is used as an auxiliary seal packing, and an inner or outer peripheral side of the main seal packing is provided. The formed seal portion is arranged to be in sliding contact with the actuator constituent member from the beginning, and the seal portion formed on the inner peripheral side or the outer peripheral side of the auxiliary seal packing is initially set with respect to the actuator constituent member. Characterized in that it is arranged in such a manner that it cannot be slidably contacted and can be slidably contacted after a predetermined period has elapsed. Sealing structure of the gist thereof.

According to the second aspect of the present invention, in a seal structure in which a seal packing is provided at a sliding portion between two actuator components that move relatively, a plurality of seal portions are provided on an inner peripheral side or an outer peripheral side of the seal packing. And one of them is used as a main seal portion, and the other is used as an auxiliary seal portion, and the main seal portion is slidably contacted with the actuator constituent member from the beginning, and the auxiliary seal portion is provided. The gist of the present invention is a seal structure of a fluid pressure actuator, characterized in that the portion is initially disengaged from being slidably contacted with the actuator component and is slidably contacted after a predetermined period of time.

According to a third aspect of the present invention, in the first or second aspect, the seal portion of the auxiliary seal packing or the auxiliary seal portion is biased in a direction away from the actuator constituent member to be elastically deformed. A seal pressing member is provided so as to be detachable from the seal portion, and the seal portion is initially kept in a state in which the seal portion cannot slide on the actuator constituent member by locking the seal pressing member. .

According to a fourth aspect of the present invention, in the third aspect, the seal portion pressing member is attached to the seal portion of the auxiliary seal packing or the auxiliary seal portion to attach the seal portion in the radial direction. The tubular member is provided with a locking portion that is elastically deformed by urging, and an operating portion used when engaging and disengaging by moving the actuator constituent members along a relative movement direction.

According to a fifth aspect of the present invention, in the fourth aspect, the seal pressing member is made of a flexible material and has a slit formed along its own axis.

According to a sixth aspect of the present invention, in the fourth or fifth aspect, the operation section is installed so as to be exposed outside the actuator. According to a seventh aspect of the present invention, in the first or second aspect, a first locking structure is provided on one of the actuator constituent members and the second locking structure is disengageable with the first locking structure on the auxiliary seal packing side.
A locking structure is provided, and the auxiliary seal packing is elastically deformed in a direction in which the seal portion is separated from the other actuator component member by expanding the diameter of the auxiliary seal packing based on locking between the two locking structures. Thus, the seal portion is initially kept in a state in which it cannot slide on the other actuator component.

According to an eighth aspect of the present invention, in the seventh aspect, the first locking structure is a plurality of locking holes,
The locking structure is a plurality of locking projections operable from outside the actuator via the locking holes.

The invention according to claim 9 is the invention according to claims 1 to 8
In any one of the above, the seal portion of the auxiliary seal packing or the auxiliary seal portion has a lip shape.

According to a tenth aspect of the present invention, in the sealing method using a seal structure in which a seal packing is provided at a sliding portion between two actuator components that move relatively, a plurality of seal packings are provided at the sliding portion. One of the seal packings is used as a main seal packing, and the other is used as an auxiliary seal packing, and a seal portion formed on the inner peripheral side or outer peripheral side of the main seal packing is attached to the actuator constituent member. Sliding contact from the beginning, the seal portion formed on the inner or outer peripheral side of the auxiliary seal packing,
The seal member of the auxiliary seal packing is slid with respect to the actuator component member after the sealing force of the seal portion of the main seal packing is reduced to some extent. The gist of the present invention is a sealing method for a fluid pressure actuator characterized in that the sealing is performed.

According to an eleventh aspect of the present invention, in the sealing method using a seal structure in which a seal packing is provided at a sliding position between two actuator components that move relative to each other, a plurality of seal packings are provided on the inner peripheral side or outer peripheral side of the seal packing. And one of them as a main seal portion, and the other as an auxiliary seal portion,
The main seal portion is slidably contacted with the actuator constituent member from the beginning, and the auxiliary seal portion is initially kept in a state in which it cannot be slidably contacted with the actuator constituent member,
The gist of the present invention is a sealing method for a fluid pressure actuator, characterized in that the auxiliary seal portion is brought into sliding contact with the actuator constituent member after the sealing force of the main seal portion is reduced to some extent.

Hereinafter, the "action" of the present invention will be described. According to the first aspect of the invention, at the beginning of use, only the seal portion of the main seal packing comes into sliding contact with the actuator constituent member. At this time, since the seal portion of the auxiliary seal packing is still in a state where sliding contact is impossible,
At least until the predetermined period elapses, the seal portion cannot be worn. That is, the sealing force of the two seal packings does not decrease at the same time, and the sealing force of the auxiliary seal packing is kept unimpaired until a predetermined period elapses. Therefore, there is little waste of sealing force,
The life of the seal can be drastically increased as compared with the related art.

According to the second aspect of the invention, at the beginning of use, only the main seal portion of the seal packing comes into sliding contact with the actuator constituent member. At this time, since the auxiliary seal portion is still in a state where sliding contact is impossible, the auxiliary seal portion cannot be worn at least until a predetermined period elapses. That is, the sealing forces of the two seal portions do not decrease at the same time, and the sealing force of the auxiliary seal portion is preserved without loss until a predetermined period elapses. Therefore, there is little waste of the sealing force, and the sealing life can be drastically increased as compared with the related art. In addition, such a seal structure is more convenient for downsizing as compared to a case where a plurality of seal packings are used.

According to the third aspect of the present invention, when the seal portion pressing body is locked on the seal portion,
The seal portion is maintained in a state in which it cannot slide on the actuator constituent members. When the locked state by the seal pressing member is released, the seal portion, which has been urged in a direction away from the actuator component, elastically returns to its original shape and slides on the actuator component. Become. Therefore, the elastic force of the sealing portion acts as a suitable sealing force, and the sealing force can be reliably preserved.

According to the fourth aspect of the present invention, by operating the operating portion, the seal portion pressing body can be easily moved along the direction of relative movement between the actuator constituting members. Therefore, the engagement / disengagement operation by the movement of the seal pressing member can be relatively easily performed.

According to the fifth aspect of the present invention, since the seal pressing member having such a slit can expand and contract the diameter by applying a deformation force, it can be attached to and detached from the actuator constituent member. It becomes convenient. Further, since the seal portion pressing body is made of a flexible material, the shape can be restored to the original shape by removing the deforming force.

According to the sixth aspect of the present invention, if the operation unit is installed so as to be exposed outside the actuator,
It is possible to externally operate the seal pressing member. Therefore, the locking of the seal pressing member can be released without intentionally disassembling the fluid pressure actuator.

According to the seventh aspect of the present invention, when the two locking structures are locked, the auxiliary seal packing is expanded in diameter, so that the seal portion slides on the actuator constituting member. Maintained in an impossible state. When such a locked state is released, the auxiliary seal packing is elastically returned to the original size, and the seal portion separated from the actuator constituent member comes into sliding contact with the actuator constituent member. Therefore, the elastic force of the auxiliary seal packing acts as a suitable sealing force. Also,
With this configuration, since the seal pressing member is not required, the structure is simplified as compared with the configuration using the same.

According to the eighth aspect of the present invention, the auxiliary seal packing is reliably expanded by locking each of the locking projections of the auxiliary seal packing in each of the locking holes of the actuator constituent member. it can. In addition, by externally operating each of the locking projections via each of the locking holes, each of the locking projections can be detached from each of the locking holes and the auxiliary seal packing can be elastically returned to the original size. Therefore, it is not necessary to deliberately disassemble the fluid pressure actuator.

According to the ninth aspect of the present invention, if the seal portion is formed in a lip shape, the seal portion is deformed so as to be pressed against the actuator component when a fluid pressure is applied. For this reason, a high sealing force can be secured, and the effect of preventing fluid leakage through the sliding contact portion is further enhanced.

According to the tenth aspect, at the beginning of use, only the seal portion of the main seal packing comes into sliding contact with the actuator constituent member. Therefore, until the sealing portion of the main seal packing is worn and the sealing force is reduced to some extent, the action of the main seal packing seals the sliding portion, thereby preventing fluid leakage therefrom. Since the seal portion of the auxiliary seal packing is in a non-slidable state, at least at this time, the seal portion cannot be worn. Then, after the sealing force of the main seal packing is reduced to some extent, the sliding portion is sealed by the action of the auxiliary seal packing, thereby preventing fluid leakage therefrom. That is, the sealing forces of the two seal packings do not decrease at the same time, and the sealing force of the auxiliary seal packing is preserved without loss until the sealing force of the main seal packing decreases to some extent. Therefore, waste of the sealing force can be minimized, and the sealing life can be significantly increased as compared with the conventional case.

According to the eleventh aspect, at the beginning of use, only the main seal portion of the seal packing comes into sliding contact with the actuator constituent member. Therefore, until the main seal part is worn and the sealing force is reduced to some extent, the action of the main seal part seals the sliding portion, thereby preventing fluid leakage therefrom. Since the auxiliary seal portion is in a state where sliding contact is impossible, at least at this time, the auxiliary seal portion cannot be worn. Then, after the sealing force of the main seal portion has decreased to some extent, the sliding portion is sealed by the action of the auxiliary seal portion, thereby preventing fluid leakage therefrom. In other words, the sealing forces of the two seal portions do not decrease at the same time, and the sealing force of the auxiliary seal portion is preserved without loss until the sealing force of the main seal portion decreases to some extent. Therefore, waste of the sealing force can be minimized, and the sealing life can be significantly increased as compared with the conventional case. In addition, such a sealing method is more convenient for downsizing as compared to a case where a plurality of seal packings are used.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] An embodiment in which the present invention is embodied in an inner peripheral sealing structure and an inner peripheral sealing method in an air cylinder 1 will be described in detail with reference to FIGS. Will be described.

FIG. 1A shows a state before the use of the air cylinder 1 as a fluid pressure actuator is started. The air cylinder 1 is used in this state until a certain period elapses from the beginning of use.

The housing 2 constituting the air cylinder 1 has a substantially cylindrical overall shape. The housing 2 as an actuator component has a packing accommodation space 3 and a piston accommodation space (not shown) therein. The packing accommodation space and the piston accommodation space
They are communicated with each other through a rod insertion hole 5 for inserting the piston rod 4.

A piston (not shown) is accommodated in the piston accommodating space so as to reciprocate along the axial direction of the housing. The piston partitions the inside of the piston housing space into two chambers (not shown). A pair of unillustrated air supply / discharge ports communicating with the pair of chambers are formed on the outer peripheral surface of the housing 2. Air as a fluid is alternately supplied to both sides of the piston through both ports, and thereby the piston is driven.

At the center of one end face of the piston,
A piston rod 4 as an actuator component is attached. The piston rod 4 passes through the rod insertion hole 5 and projects outside the cylinder. Therefore,
When the piston is driven, the piston rod 4 protrudes and retracts from the rod-side end surface of the air cylinder 1.

In the packing housing space 3, two seal packings 6, 7 are housed in a state of being inserted through the piston rod 4. In FIG. 1A, the one located on the right side (the side closer to the piston housing space) is called the main seal packing 6, and in FIG. 1A the one located on the left side (the side farther from the piston housing space) is the auxiliary seal packing 6. Let's call it 7.

In the present embodiment, both seal packings 6, 7 have the same shape. Both the members 6 and 7 are annular, and are molded by using an elastic material such as rubber as a material. These seal packings 6,7 are 2
Since the lip-shaped seal portions 8 and 9 are provided at the locations, the lip-shaped seal portions 8 and 9 have a substantially Y-shaped cross-sectional shape. An outer seal portion 8 is located on the outer peripheral side in the seal packings 6 and 7,
An inner seal portion 9 is located on the inner peripheral side. The distal end of the outer seal portion 8 is in contact with the inner wall surface of the packing accommodation space 3. Further, the outer seal portion 8 and the inner seal portion 9 protrude from the annular base portion 10, and both ends thereof face the direction of the piston housing space. That is,
The distal ends of the seal portions 8 and 9 are oriented in a direction substantially opposite to the flow direction when air leaks. When the air pressure is applied, the two seal portions 8 and 9 are deformed in such a manner that their tips are separated from each other.

The air cylinder 1 has a pressing sleeve 11 as a seal pressing member. As shown in FIG. 2, the pressing sleeve 11 is a cylindrical member, and has a center hole 12 through which the piston rod 4 can be inserted. The inner diameter of the center hole 12 is desirably designed to be large enough that the pressing sleeve 11 itself does not slide on the piston rod 4 when the air cylinder 1 is used.

A flange 14 as an operation part is formed at one end of the cylindrical locking part 13 constituting the pressing sleeve 11. In the state of FIG.
Are inserted into the rod insertion hole 5 as a whole. In such a fully inserted state, the tip of the locking portion 13 is designed to reach just half the depth of the packing accommodation space 3. Accordingly, the locking portion 13 does not lock to the inner seal portion 9 of the main seal packing 6, but
It is possible to engage the inner seal 9 of the auxiliary seal packing 7. That is, as shown in FIG. 1A, the inner seal portion 9 of the main seal packing 6 is arranged to be in sliding contact with the outer peripheral surface of the rod from the beginning. On the other hand, the inner seal portion 9 of the auxiliary seal packing 7
Are arranged so as not to be able to slide on the outer peripheral surface of the rod and to be able to slide after a predetermined period of time. And
The locking portion 13 of the pressing sleeve 11 serves to keep the seal portion 9 away from the outer peripheral surface of the rod by urging the inner seal portion 9 in the radial direction to elastically deform the inner seal portion 9.

At the leading edge of the locking portion 13, there is provided a roll-up portion 13a which is rolled outward. The presence of the turned-up portion 13a prevents the inner seal portion 9 from dropping out of the locking portion 13, so that the locking of the inner seal portion 9 becomes more reliable. In the state shown in FIG. 1A, the inner end surface of the flange 14 projecting from the rod insertion hole 5 is in contact with the rod-side end surface 2 a of the housing 2. That is,
The flange 14 is installed so as to be exposed outside the cylinder.

The flange 14 is used to move the pressing sleeve 11 along the axial direction of the piston rod 4 (ie, the direction of relative movement between the actuator components). Thereby, the engagement / disengagement operation of the locking portion 13 and the inner seal portion 9 is performed.

The pressing sleeve 11 is a cylindrical member made of a flexible material, and has a slit 15 formed along its own axis as shown in FIG. Therefore, by applying a deforming force, it is possible to expand or contract the diameter of the pressing sleeve 11 at the time of attachment / detachment. Further, since the pressing sleeve 11 is made of a flexible material,
When the deformation force is removed, the shape returns to its original shape.

FIG. 1 (b) shows an air cylinder 1 in which a certain period of time has elapsed since the start of use, more specifically, a state in which the inner seal portion 9 of the main seal packing 6 has been worn. It is shown. That is, if no air pressure is applied, a gap is partially formed between the outer peripheral surface of the rod and the inner seal portion 9, so that the sealing force is reduced to some extent. For this reason, if the use is continued, there is a possibility that air leaks from the sliding portion to the outside. Therefore, in this case, the pressing sleeve 11 is pulled out from the air cylinder 1 for use by moving the pressing sleeve 11 along the axial direction of the piston rod 4. Then, the inner seal portion 9 of the auxiliary seal packing 7 elastically returns to the original shape, and comes into sliding contact with the outer peripheral surface of the rod. Therefore, the elastic force of the auxiliary seal packing 7 acts as a suitable sealing force, and air leakage from the sliding portion to the outside is prevented.

Until the inner seal portion 9 of the main seal packing 6 is worn down and the sealing force is reduced to some extent, the sliding portion is sealed by the action of the main seal packing 6 to prevent air leakage therefrom. Is done. Since the inner seal portion 9 of the auxiliary seal packing 7 is in a state where sliding contact is impossible, at least the seal portion 9 cannot be worn at least in the state of FIG. Then, after the sealing force of the main seal packing 6 is reduced to some extent, the sliding portion is sealed by the action of the auxiliary seal packing 7 to prevent air leakage therefrom. That is,
The sealing force of the two seal packings 6 and 7 does not decrease at the same time, and the sealing force of the auxiliary seal packing 7 is preserved without loss until the sealing force of the main seal packing 6 decreases to some extent.

The features and effects of this embodiment are listed below. (A) In the air cylinder 1 of the present embodiment, since the sealing force of the auxiliary seal packing 7 is preserved without being impaired for a certain period, waste of the sealing force is minimized. That is, since one seal location is originally sufficient, there is no waste as in the prior art of FIG. 10 in which two seal locations are provided from the beginning. Therefore, the life of the seal can be significantly increased as compared with the conventional case. Specifically,
In the case of the present embodiment, if the seal packing 6,
It is possible to achieve a seal life approximately twice as long as the case where only one is used.

(B) In the air cylinder 1 of the present embodiment,
The pressing sleeve 11 as described above is used as the seal pressing body. Therefore, when the pressing sleeve 11 is engaged with the inner seal portion 9 of the auxiliary seal packing 7, the seal portion 9 is maintained in a state in which the seal portion 9 cannot slide on the outer peripheral surface of the rod. When the locked state by the pressing sleeve 11 is released, the seal portion 9 urged in a direction away from the outer peripheral surface of the rod elastically returns to its original shape and comes into sliding contact with the outer peripheral surface of the rod. That is, with such a pressing sleeve 11, the sealing force of the inner seal portion 9 of the auxiliary seal packing 7 can be reliably preserved.

(C) Pressing sleeve 1 in this embodiment
1 is provided with a locking portion 13 and a flange 14. Therefore, by holding and pulling the flange 14, the pressing sleeve 11 can be easily moved and removed along the axial direction of the piston rod 4. Therefore, the operation of releasing the engagement by the movement of the pressing sleeve 11 can be performed relatively easily. Further, since the pressing sleeve 11 is made of a flexible material and has the slits 15, it is possible to increase or decrease the diameter by applying a deformation force. Therefore, it can be easily attached to and detached from the housing 2, which is convenient. Furthermore, since the flange 14 is installed so as to be exposed outside the cylinder, the pressing sleeve 11
Can be operated externally. Therefore, the locking of the pressing sleeve 11 can be released even if the air cylinder 1 is not intentionally disassembled or has a structure that cannot be disassembled. As described above, the air cylinder 1 of the present embodiment is extremely excellent in handling and operability.

(D) In the air cylinder 1 of the present embodiment,
Both seal portions 8, 9 of both seal packings 6, 7 have a lip shape. Therefore, when air pressure is applied from the piston housing space side, the outer seal portion 8 is pressed against the inner wall surface side of the packing housing space 3 and the inner seal portion 9 is deformed so as to be pressed against the rod outer circumferential surface side. For this reason, a high sealing force can be ensured on the surface to be sealed, and the effect of preventing air leakage to the outside via the sliding contact portion is further enhanced. [Second Embodiment] Next, an inner seal structure and an inner seal method according to a second embodiment will be described in detail with reference to FIGS. Portions common to the first embodiment are denoted by the same member numbers.

FIG. 4A shows a state before the use of the air cylinder 21 is started. Until a certain period elapses from the beginning of use, the same air cylinder 2
1 is used in this state. FIG. 4B shows the air cylinder 21 after a certain period of time has elapsed since the start of use.

The air cylinder 21 of this embodiment differs from the air cylinder 1 of the first embodiment in that the air cylinder 21 does not include the pressing sleeve 11, and has the following locking structure instead.

A locking hole 24 as a first locking structure is formed in the rod-side end surface 2a of the housing 2. The locking hole 24 has a circular cross section and a plurality (here, four), and penetrates the front and back of the rod-side end surface 2a. As shown in FIG. 3, each locking hole 24 is arranged so as to surround the piston rod 4 and to be rotated around the piston rod 4.

On the other hand, the annular base 10 of the auxiliary seal packing 23 is provided with a locking projection 25 as a second locking structure that can be engaged with and disengaged from each locking hole 24. The locking projections 25 are columnar and plural (here, four), and they are provided at positions corresponding to the respective locking holes 24. Here, a first virtual circle where each locking hole 24 is seated and a second virtual circle where each locking projection 25 is seated are assumed. The diameter of the first virtual circle needs to be designed to be larger than the diameter of the second virtual circle when no stress is applied to the auxiliary seal packing 7. Therefore, when each locking projection 25 is locked in each locking hole 24 as shown in FIG.
3 is pulled in the radial direction to be in a state of slightly expanded diameter. At this time, the inner seal portion 9 of the auxiliary seal packing 23
Is elastically deformed in a direction away from the outer peripheral surface of the rod, and is kept in a non-slidable state for a certain period.

The inner seal portion 9 of the main seal packing 22
When the sealing force is reduced to some extent due to abrasion, the locking between the locking holes 24 and the locking projections 25 is released as shown in FIG. In particular,
The head of each locking projection 25 visible in each locking hole 24 may be pressed with a pointed object. Then, each locking projection 25 is disengaged from each locking hole 24 and there is no pulling force. As a result, the auxiliary seal packing 23 resiliently returns to its original shape, and the inner seal portion 9 slides on the rod outer peripheral surface. Become. Therefore, the elastic force of the auxiliary seal packing 23 acts as a suitable sealing force, and air leakage from the sliding portion to the outside is prevented.

The operation and effects characteristic of the present embodiment will be listed below. (A) Also in the present embodiment, the sealing force of the two seal packings 22 and 23 does not decrease at the same time, and the sealing force of the auxiliary seal packing 23 is not impaired until the sealing force of the main seal packing 22 decreases to some extent. It is preserved. Therefore, the waste of the sealing force can be minimized, and the life of the seal can be significantly extended.

(B) In the air cylinder 21 of the present embodiment, the locking of the locking hole 24 and the locking projection 25 allows the inner seal portion 9 of the auxiliary seal packing 23 to be maintained for a certain period.
Is maintained in a state in which it cannot slide on the outer peripheral surface of the rod. Therefore, the sealing force of the inner seal portion 9 of the auxiliary seal packing 23 can be reliably preserved. In addition, since a seal portion pressing body such as the pressing sleeve 11 is not required, the structure is simplified as compared with a structure using the same.

(C) In this air cylinder 21, each locking projection 25 is removed from each locking hole 24 by a pressing operation from the outside of the cylinder, and the auxiliary seal packing 23 is elastically returned to its original size. be able to. Therefore,
It is not necessary to disassemble the air cylinder 21, and the air cylinder 21 can be made extremely excellent in handling and operability. [Third Embodiment] Next, an inner seal structure and an inner seal method according to a third embodiment will be described in detail with reference to FIG. Portions common to the first embodiment are denoted by the same member numbers.

FIG. 5A shows a state before the use of the air cylinder 31 is started. Until a certain period elapses from the beginning of use, the air cylinder 3
1 is used in this state. FIG. 5B shows the air cylinder 31 after a certain period of time has elapsed from the start of use.

In the air cylinder 31 of this embodiment, only one seal packing 32 is used. The seal packing 32 has two lip-shaped seal portions 33 and 34 on the inner peripheral side. In FIG. 4A, the one located on the right side (closer to the piston housing space) is called the main seal portion 33, and in FIG. 5A the one located on the left side (farther away from the piston housing space) is the auxiliary seal portion. Let's call it 34. These seal portions 33, 34
Has a role corresponding to the inner seal portion 9 described in the first embodiment. In addition, both seal portions 33, 34
Projections are provided from the annular base 35 so as to have substantially the same length and the same angle.

When the pressing sleeve 11 is inserted as shown in FIG. 5 (a), only the main seal portion 33 comes into sliding contact with the outer peripheral surface of the rod. As a result of the auxiliary seal part 34 being pressed in the radial direction by the locking part 13, the auxiliary seal part 34 is arranged so as not to be able to slide on the rod outer peripheral surface.

When the main seal portion 33 is worn and the sealing force is reduced to some extent, the pressing sleeve 11 is pulled out and used as shown in FIG. Then, the auxiliary seal portion 34 elastically returns to the original shape, and comes into sliding contact with the outer peripheral surface of the rod. Therefore, seal packing 3
The elastic force of the auxiliary seal portion 34 of No. 5 acts as a suitable sealing force, and air leakage from the sliding portion to the outside is prevented.

Now, the characteristic effects of the present embodiment will be enumerated below. (A) Also in the present embodiment, the sealing force of the two seal portions 33 and 34 of the seal packing 32 does not decrease at the same time.
Until the sealing force of the main seal portion 33 decreases to some extent, the sealing force of the auxiliary seal portion 34 is preserved without being impaired. Therefore, the waste of the sealing force can be minimized, and the life of the seal can be significantly extended. It goes without saying that the respective effects b, c, and d described in the first embodiment are achieved.

(B) According to the present embodiment, compared to the first embodiment using a plurality of seal packings 6 and 7,
The seal packing 32 itself can be formed small. Therefore, the packing accommodation space is also small, which is convenient for making the whole compact. [Fourth Embodiment] Next, an outer peripheral sealing structure and an outer peripheral sealing method according to a fourth embodiment will be described in detail with reference to FIG.

FIG. 6A shows a state before the use of the air cylinder 41 is started. Until a certain period elapses from the beginning of use, the air cylinder 4
1 is used in this state. FIG. 6B shows the air cylinder 41 after a certain period of time has elapsed from the start of use.

Both ends of the cylinder tube 42 as an actuator component are closed by covers (not shown). As a result, a piston accommodation space 43 is formed in the cylinder tube 42. In the piston housing space 43, a piston 44 as an actuator constituent member is housed so as to be able to reciprocate along the tube axis direction. The piston 44 divides the piston housing space 43 into two pressure action chambers.

An annular packing fitting groove 45 as a packing mounting portion is formed on the outer peripheral portion of the piston 44. Two seal packings 46 and 47 are fitted in the packing mounting groove 45. 6 (a) is referred to as a main seal packing 46, and the one located on the right side in FIG. 6 (a) is referred to as an auxiliary seal packing 47. Both seal packings 46 and 47 in the present embodiment also have the same shape,
In addition, the outer peripheral seal portion 8A and the inner peripheral seal portion 9A having a lip shape are provided.

Pressing Sleeve 48 as Sealing Section Pressing Body
Is provided with a cylindrical locking portion 49. FIG. 6 (a)
The locking portion 49 is provided with an auxiliary seal packing 47.
Is locked to the outer seal portion 8A. As a result, the outer seal portion 8A of the main seal packing 46 is arranged to be in sliding contact with the inner circumferential surface of the tube from the beginning. On the other hand, the outer seal portion 8A of the auxiliary seal packing 47 is
It is arranged so that it cannot slide on the inner circumferential surface of the tube at first and can slide after a predetermined period.

That is, the locking portion 49 of the pressing sleeve 48
Plays a role of keeping the seal portion 9 away from the inner circumferential surface of the tube by urging the outer seal portion 9 of the auxiliary seal packing 47 in the radial direction to elastically deform the outer seal portion 9.

Outer seal portion 8 of main seal packing 46
If wear occurs in A and the sealing force decreases to some extent,
As shown in FIG. 6B, the pressing sleeve 48 is used by being pulled out in the tube axis direction. Then, the outer seal portion 8A of the auxiliary seal packing 47 elastically returns to the original shape, and comes into sliding contact with the inner circumferential surface of the tube. Therefore, the elastic force of the outer seal portion 8A of the auxiliary seal packing 47 acts as a suitable sealing force. As a result, air leakage between the pressure action chambers through the gap formed between the inner peripheral surface of the tube and the outer peripheral surface of the piston is prevented.

Now, the characteristic effects of this embodiment will be listed below. (A) Also in the present embodiment, the sealing force of the two seal packings 46 and 47 does not decrease at the same time, and the sealing force of the auxiliary seal packing 47 does not deteriorate until the sealing force of the main seal packing 46 decreases to some extent. It is preserved. Therefore, the waste of the sealing force can be minimized, and the life of the seal can be significantly extended.

(B) According to this embodiment, the first embodiment
The functions and effects b and d listed in above can also be obtained. [Fifth Embodiment] Next, an outer peripheral sealing structure and an outer peripheral sealing method according to a fifth embodiment will be described in detail with reference to FIG.

FIG. 7A shows a state before the use of the air cylinder 51 is started. Until a certain period elapses from the beginning of use, the air cylinder 5
1 is used in this state. FIG. 7B shows the air cylinder 51 after a certain period of time has elapsed since the start of use.

Here, a seal packing 5 having two lip-shaped seal portions 53 and 54 on the outer peripheral side thereof.
Only one is used. When the pressing sleeve 48 is inserted as shown in FIG. 7A, only the main seal portion 53 comes into sliding contact with the inner circumferential surface of the tube. Auxiliary seal part 54
As a result of being pressed in the radial direction by the locking portion 49, it is arranged in a state in which it cannot slide on the inner circumferential surface of the tube.

When the main seal portion 53 is worn and the sealing force is reduced to some extent, the pressing sleeve 48 is pulled out and used as shown in FIG. 7B. Then, the auxiliary seal portion 54 elastically returns to the original shape, and comes into sliding contact with the inner peripheral surface of the tube. Therefore, the elastic force of the auxiliary seal portion 54 of the seal packing 52 acts as a suitable sealing force, and air leakage from a sliding portion is prevented.

Now, the characteristic effects of the present embodiment will be enumerated below. (1) Also in the present embodiment, the sealing force of the two seal portions 53 and 54 of the seal packing 52 does not decrease at the same time.
Until the sealing force of the main sealing portion 53 decreases to some extent, the sealing force of the auxiliary sealing portion 54 is preserved without being impaired. Therefore, the waste of the sealing force can be minimized, and the life of the seal can be significantly extended.

(2) According to the present embodiment, the seal packing 52 itself can be formed smaller than in the fourth embodiment. Therefore, the size of the packing accommodation groove 45 is also small, which is convenient for making the whole compact. [Sixth Embodiment] Next, an inner seal structure and an inner seal method according to a sixth embodiment will be described in detail with reference to FIG.

FIG. 8A shows a state before the use of the air cylinder 61 is started. Until a certain period elapses from the beginning of use, the air cylinder 6
1 is used in this state. FIG. 8B shows the air cylinder 61 after a certain period of time has elapsed from the start of use.

In this embodiment, one main seal packing 6 and two auxiliary seal packings 7 are used.
In FIG. 8, the one on the right side is referred to as a first-stage auxiliary seal packing 7, and the one on the left side is referred to as a second-stage auxiliary seal packing 7.

Here, in order to accommodate three seal packings 6, 7, the packing accommodation space 3 is formed larger than that of the first embodiment. The pressing sleeve 11 </ b> A is designed such that the distal end of the locking portion 13 reaches a depth of about ／ of the packing accommodation space 3 in the fully inserted state. Therefore, as shown in FIG.
Both of the inner seal portions 9 of the auxiliary seal packing 7 are arranged so as not to be able to slide on the outer peripheral surface of the rod at first and to be able to slide after a predetermined period.

When the inner seal portion 9 of the main seal packing 6 is worn, as shown in FIG. 8B, the pressing sleeve 11A is moved along the axial direction of the piston rod 4.
Is moved by the length of one auxiliary seal packing 7. Then, the inner seal portion 9 of the first-stage auxiliary seal packing 7 elastically returns to the original shape, and comes into sliding contact with the outer peripheral surface of the rod. Therefore, the elastic force of the first-stage auxiliary seal packing 7 acts as a suitable sealing force, and air leakage from the sliding portion to the outside is prevented.

When the inner seal portion 9 of the first-stage auxiliary seal packing 7 is also worn, as shown in FIG. 8C, the pressing sleeve 11A is further moved and pulled out from the piston rod 4. Use in state. Then, the inner seal portion 9 of the second-stage auxiliary seal packing 7 elastically returns to its original shape, and comes into sliding contact with the outer peripheral surface of the rod. Therefore, the elastic force of the second-stage auxiliary seal packing 7 acts as a suitable sealing force, and air leakage from the sliding portion to the outside is prevented.

That is, the sealing forces of the three seal packings 6 and 7 do not decrease at the same time, and the sealing forces of the auxiliary seal packings 7 are not impaired until the sealing force of the main seal packing 6 decreases to some extent. It is preserved. Similarly, until the sealing force of the first-stage auxiliary seal packing 7 decreases to some extent, the sealing force of the second-stage auxiliary seal packing 7 is preserved without being impaired.

Now, the characteristic effects of the present embodiment will be described below. (A) Even with the air cylinder 61 having such a configuration,
It goes without saying that the same operation and effect as in the first embodiment are obtained. In particular, according to the present embodiment, it is possible to achieve a seal life that is approximately three times that of the case where only one seal packing 6, 7 is used, and the seal life is dramatically increased as compared with the related art.

The present invention is not limited to each of the above-described embodiments 1 to 6, but may be modified to another form as described below. As in another example shown in FIG. 9, it is preferable to form a cutout recess 66 on the inner end surface side of the pressing sleeve 11 </ b> B which is a seal pressing member. In this way, the tip of a tool or the like can be engaged with the notch recess 66. Therefore, even if the flange 14 is in close contact with the rod-side end surface 2a, a gap can be formed between the flange 14 and the pressing sleeve 11B, and the pressing sleeve 11B can be more easily pulled out from the piston rod 4.

In the second embodiment, a concave locking structure such as a locking hole 24 is employed as a second locking structure on the auxiliary seal packing 23 side, and a locking projection is formed as a first locking structure on the housing 2 side. It is also possible to adopt a convex locking structure such as 25. However, in view of the fact that external operation becomes possible, the configuration of the second embodiment is more preferable.

The seal portions 8, 9,... Are not necessarily limited to the lip shape, but may have other shapes. ◎ In the embodiment using a plurality of seal packings 6, 7,..., The seal packings 6, 7,. Further, the number of auxiliary seal packings 7, 23,... Is not limited to one or two, but may be three or more.

The main seal portion 3 is provided on the seal packing 35.
Embodiment 3 in which one is provided and one auxiliary seal portion 34 is provided.
, Two or more auxiliary seal portions 34 are provided,
In addition, as shown in FIG. 8, they may be used with a time difference.

The seal structure and the seal method of the present invention can be applied to a cylinder using other fluids other than the air cylinder. Further, the present invention is not limited to such a hydraulic cylinder and can be applied to other hydraulic actuators.

Here, in addition to the technical ideas described in the claims, the technical ideas grasped by the above-described embodiments are listed below together with their effects. (1) The seal structure for a fluid pressure actuator according to any one of claims 4 to 6, wherein a curled portion that curls outward is provided at a leading edge of the locking portion. With this configuration, the sealing portion is prevented from falling off from the locking portion, and the locking is more reliably performed.

(2) In any one of claims 4 to 6, and the technical idea 1, the operating portion is a flange formed on an outer end side of the locking portion, and is formed on an inner end surface side of the flange. Is a seal structure for a fluid pressure actuator, wherein a notch recess is formed. With this configuration, the tip of a tool or the like can be engaged with the cutout recess, so that the seal portion pressing body can be more easily pulled out.

The technical terms used in the present specification are defined as follows. “Actuator component: A component that constitutes a hydraulic actuator. In a hydraulic cylinder, it refers to, for example, a piston rod, a housing, a cylinder tube, a piston, a slide table, and the like.”

[0088]

As described in detail above, according to the first aspect of the present invention, it is possible to provide a seal structure of a fluid pressure actuator which can greatly increase the seal life.

According to the second aspect of the present invention, it is possible to provide a seal structure of a fluid pressure actuator that can greatly extend the life of the seal and is advantageous in reducing the size.

According to the third aspect of the present invention, the sealing force of the sealing portion can be reliably preserved. According to the fourth, fifth, and sixth aspects of the present invention, it is suitable for realizing a fluid pressure actuator excellent in handleability and operability.

According to the seventh and eighth aspects of the invention, it is suitable for realizing a fluid pressure actuator which is excellent in handling and operability and has a simple structure. According to the ninth aspect, the effect of preventing fluid leakage can be further enhanced.

According to the tenth aspect of the present invention, it is possible to provide a sealing method for a fluid pressure actuator capable of greatly extending the sealing life. Claim 11
According to the invention described in (1), it is possible to provide a sealing method for a fluid pressure actuator, which can greatly extend the life of the seal and is advantageous in reducing the size.

[Brief description of the drawings]

FIGS. 1A and 1B are partial cross-sectional views of an air cylinder having a seal structure according to a first embodiment.

FIG. 2 is a partially exploded perspective view of the air cylinder.

FIG. 3 is a partial perspective view of an air cylinder provided with a seal structure according to a second embodiment.

FIGS. 4A and 4B are partial cross-sectional views of the air cylinder.

FIGS. 5A and 5B are partial cross-sectional views of an air cylinder provided with a seal structure according to a third embodiment.

FIGS. 6A and 6B are partial cross-sectional views of an air cylinder provided with a seal structure according to a fourth embodiment.

FIGS. 7A and 7B are partial cross-sectional views of an air cylinder provided with a seal structure according to a fifth embodiment.

FIGS. 8A to 8C are partial cross-sectional views of an air cylinder provided with a seal structure according to a sixth embodiment.

FIG. 9A is a front view of another example of the seal pressing body,
(B) is the side view.

FIG. 10 is a partial sectional view of an air cylinder provided with a conventional seal structure.

[Explanation of symbols]

1, 2, 31, 31, 41, 51, 61: air cylinder as a fluid pressure actuator, 2: housing as an actuator component, 3 ... piston rod as an actuator component, 6, 22, 46 ... main seal packing, 7 , 23,47… Auxiliary seal packing, 8,
8A: outer seal portion, 9, 9A: inner seal portion, 11,
11A, 11B: a pressing sleeve as a sealing portion pressing body; 13, a locking portion; 14, a flange as an operating portion;
5 ... slit, 24 ... locking hole as first locking structure, 2
5: locking projection as a second locking structure; 33, 53: main seal portion; 34, 54: auxiliary seal portion; 42: cylinder tube as an actuator component; 44: piston as an actuator component.

Claims (11)

[Claims] 1. A seal structure in which a seal packing is provided at a sliding position between two actuator components that move relative to each other, wherein a plurality of seal packings are provided at the sliding position, and one of the seal packings is provided. Is used as a main seal packing, and the rest is used as an auxiliary seal packing, and a seal portion formed on the inner peripheral side or the outer peripheral side of the main seal packing is arranged so as to be in sliding contact with the actuator constituent member from the beginning. A seal portion formed on the inner peripheral side or the outer peripheral side of the auxiliary seal packing is arranged so as not to be initially slidable on the actuator constituent member and to be slidable after a predetermined period of time. Seal structure of fluid pressure actuator. 2. A seal structure in which a seal packing is provided at a sliding portion between two relatively moving actuator constituent members, wherein a plurality of seal portions are provided on an inner peripheral side or an outer peripheral side of the seal packing. One as a main seal portion, and the other as an auxiliary seal portion, the main seal portion is arranged to be in sliding contact with the actuator constituent member from the beginning, and the auxiliary seal portion is attached to the actuator constituent member. On the other hand, a seal structure for a fluid pressure actuator characterized in that it is initially slidable and slidable after a predetermined period of time. 3. A seal pressing member for urging the seal portion of the auxiliary seal packing or the auxiliary seal portion in a direction away from the actuator constituent member to elastically deform the seal portion is detachable from the seal portion. 3. The fluid according to claim 1, wherein said seal portion is initially kept out of sliding contact with said actuator member by locking said seal portion pressing body. Seal structure for pressure actuator. 4. A locking portion for pressing the seal portion in a radial direction by elastically deforming the seal portion by locking the seal portion pressing body with the seal portion of the auxiliary seal packing or the auxiliary seal portion; The seal structure for a fluid pressure actuator according to claim 3, characterized in that the seal structure is a cylindrical member provided with an operation unit used for performing an engagement / disengagement operation by moving the actuator constituent members along a relative movement direction. 5. The seal for a fluid pressure actuator according to claim 4, wherein said seal pressing member is made of a flexible material and has a slit formed along its own axial direction. Construction. 6. The seal structure for a fluid pressure actuator according to claim 4, wherein the operation section is installed so as to be exposed outside the actuator. 7. A first locking structure is provided on one of the actuator constituent members, and a second locking structure is provided on the auxiliary seal packing side, the second locking structure being detachable from the first locking structure. The auxiliary seal packing is elastically deformed in a direction to separate the seal portion from the other actuator constituent member by expanding the diameter of the auxiliary seal packing based on the locking of the seal member, thereby forming the seal portion in the other actuator configuration. 3. The seal structure for a fluid pressure actuator according to claim 1, wherein the member is initially kept out of sliding contact with the member. 8. The first locking structure includes a plurality of locking holes,
The seal structure for a fluid pressure actuator according to claim 7, wherein the second locking structure is a plurality of locking projections operable from outside the actuator via the locking holes. 9. The seal structure for a fluid pressure actuator according to claim 1, wherein the seal portion of the auxiliary seal packing or the auxiliary seal portion has a lip shape. 10. A sealing method using a seal structure in which a seal packing is provided at a sliding portion between two actuator components that move relative to each other, wherein a plurality of seal packings are provided at the sliding portion, and among the seal packings, One is used as a main seal packing, and the other is used as an auxiliary seal packing. A seal portion formed on the inner peripheral side or the outer peripheral side of the main seal packing is slid from the beginning on the actuator constituent member. The seal part formed on the inner peripheral side or the outer peripheral side of the auxiliary seal packing is initially kept in a state where it cannot slide on the actuator constituent member, and the sealing force of the seal part of the main seal packing is reduced. After lowering to some extent, the seal part of the auxiliary seal packing is A method for sealing a fluid pressure actuator, wherein the method is adapted to make sliding contact with the fluid pressure actuator. 11. A sealing method using a seal structure in which a seal packing is provided at a sliding position between two actuator components that move relative to each other, wherein a plurality of seal portions are provided on an inner peripheral side or an outer peripheral side of the seal packing. One of them is used as a main seal portion, and the other is used as an auxiliary seal portion. The main seal portion is slid in contact with the actuator component member from the beginning, and the auxiliary seal portion is attached to the actuator component member. On the other hand, a fluid characterized in that it is initially kept in a non-slidable state, and the auxiliary seal portion is slidably contacted with the actuator constituent member after the sealing force of the main seal portion is reduced to some extent. Pressure actuator sealing method.