JP3499198B2 - Seal structure of piston device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a seal structure of a moving piston device. 2. Description of the Related Art For example, ceramic powders are vacuumed.
Fixie used in molding equipment that compresses and molds at high pressure
The thrust of the piston is 1,000 to several thousand tons, or
Reaches 10,000 tons. The piston is mainly the pressure of the fluid
Slides in the cylinder, but does not respond to fluid pressure.
Cylinder bore diameter directly affects the thrust.
To reduce the size of the device, the fluid pressure must be increased.
No. [0003] To increase the fluid pressure, the pressure of the fluid supply source is increased.
Increase the power or incorporate a pressure device in the middle
However, this high fluid pressure causes the piston and cylinder to
Because it also joins the packing provided between
Withstand voltage must be considered. However, sliding fixie
The pressure resistance of the packing generally used for
2MPa (630kg / cm ^Two ) Is considered the limit,
About 69MPa (700kg / cm ^Two ) With higher pressure resistance
Packing is almost nonexistent. If the packing is used at a pressure higher than the withstand pressure,
The life of the packing may be shortened, or the flow may occur when the piston slides under pressure.
Body leaks occur. When the piston presses and slides
If a fluid leak occurs, thrust will be insufficient.
Need to keep sending the fluid
In situations where an intermediate stop is required, fluid
If a lock occurs, the piston cannot be locked.
I will. By the way, conventionally, in the field of rotary pumps,
In order to protect the bearing of the rotating shaft,
To reduce the pressure difference between the high pressure side and the low pressure side.
Are known. For example, Japanese Patent Application Laid-Open No.
There is an apparatus described in Japanese Patent No. 4597. The device described in Japanese Patent Application Laid-Open No. Hei 3-164597 is disclosed.
The high pressure side in the casing through which the pump feed fluid flows
Low-pressure side liquid chamber containing liquid chamber and low-pressure stage mechanical seal
Through a pressure reducing valve mechanism.
The pressure is reduced from the high pressure side liquid chamber to the low pressure side liquid chamber through
It is configured to replenish the liquid. According to this device, the pressure reducing valve is provided from the high-pressure side liquid chamber.
The fluid depressurized through the mechanism is a mechanical
To the low pressure side liquid chamber as seal liquid for the
And the mechanical stages of the high-pressure stage and low-pressure stage
Can always be used in a stable state
I have. In such devices, the mechanical seal
It is fixed between the pressure side liquid chamber and the low pressure side liquid chamber. [0008] On the other hand, the piston device
When the piston slides inside the cylinder,
Clearance is always provided between the piston and piston.
Contact the cylinder during this time and slide with the piston.
Packing is interposed. These packings are subject to pressure
The biggest point is not to leak fluid
Designed to reduce rubber elasticity of rubber and elastomers
Is used. [0009] However, rubber or elastomer or the like
If the kin is used under high pressure, the packing will
May get into the clearance between the
The fluid closes on the sliding surface due to close contact with the
It causes many problems such as heat generation and wear.
U. As a result, the packing is damaged in a short time,
Of life. Accordingly, in the present invention, Japanese Patent Laid-Open No.
Application of the conventional pressure reducing valve mechanism described in Japanese Patent No. 64597
And operate the piston with a pressure higher than the pressure resistance of the packing.
Between the cylinder and piston without the above problems
Seal, and stable piston movement even under high pressure
Provided is a seal structure of a piston device which enables the operation. [0011] The present invention provides a cylinder,
A piston that slides in opposition to the cylinder;
The cylinder chamber formed between the
The seal structure of the piston device that
To close the clearance between the cylinder and piston.
A plurality of packings are arranged on the sliding surface between the cylinder and piston.
And a cylinder between the multiple packings
A pressure regulation mechanism is provided to introduce and reduce the pressure of the fluid in the room in stages.
It is characterized by having. [0012] Thereby, the distance between the cylinder and the piston is
Reduce the pressure difference between the clearances on both sides of the packing
Pressure applied to the packing
It is smaller than the pressure at which the piston operates. Also, average
The fluid is supplied between the multiple packings
Therefore, the packing comes into close contact with the cylinder,
Never happen. Therefore, at a pressure higher than the pressure resistance of the packing,
Even if the piston is operated, the packing deforms and the cylinder
Into the clearance between the piston and the piston
Generation of heat and abrasion of the sliding part are prevented.
Therefore, stable operation of the piston is possible even under high pressure.
You. Therefore, rubber having rubber elasticity
Or it is possible to use an elastomer type
The rubber elasticity makes the clearance between the cylinder and piston
It is possible to securely close the alance and prevent fluid leakage
it can. The pressure regulating mechanism further comprises a
When the pressure is reduced, the fluid between the multiple packings
It is desirable that they be issued. Cylinder chamber pressure
When the pressure is reduced, the fluid between the multiple packings
By putting it out, it leads between multiple packings
To release the increased pressure.
The pressure acting on the packing during pressurization can be reduced
You. Alternatively, a plurality of packings may be used for the packing.
Prevents leakage of fluid into the gap between multiple packings
It is desirable to have a function that allows the fluid to leak. this
This prevents fluid leakage when the cylinder chamber is pressurized.
To efficiently pressurize and slide the piston.
By leaking fluid between the strip packings,
Increased pressure introduced between multiple packings
Releases the force and makes the piston smoothly slide under reduced pressure
It becomes possible. [0016] The packing and the pressure adjusting mechanism may include a piston.
On the sliding part of the head and the sliding part of the piston rod.
It is desirable that each is provided. This allows
Clear the sliding parts of the piston head and rod.
Reducing the pressure applied to the packing that blocks Alance
The piston can operate stably even under high pressure.
You. FIG. 1 shows an embodiment of the present invention.
FIG. 2 is a schematic view showing the configuration of a piston device, and FIG.
FIG. As shown in FIG. 1, in the embodiment of the present invention,
The piston device in the cylinder 1 and the inside of the cylinder 1
A piston head 2 that slides.
To output the work of the piston head 2
Stone rod 3 is connected. Also, the piston head
Cylinder 1 is made of the first liquid as a cylinder chamber
The first chamber 1a and the second chamber 1a are divided into a chamber 1a and a second chamber 1b.
Fluid lines 4a and 4b are connected to the two-liquid chamber 1b, respectively.
Have been. The piston which slides facing the cylinder 1
The sliding surface of the cylinder 2 contacts the inner surface of the cylinder 1
The clearance 5 between the piston 1 and the piston head 2 is closed.
Rubber packing (one-way pressure-resistant packing 6a, 6b
And four O-rings 7a, 7b).
A piston rod 3 that slides facing the cylinder 1
The same sliding surface as the one-way pressure-resistant packing 6a
A pressure-resistant packing 6c is provided. The one-way pressure-resistant packings 6a and 6b are pistons.
Provided on both outer sides of the sliding surface of the head 2,
Kin 6a has a pressure resistance (maximum receiving pressure) from the first liquid chamber 1a direction.
About 59MPa (600kg / cm ^Two )), One way
The pressure-resistant packing 6b has a pressure resistance (most
Large receiving pressure about 59MPa (600kg / cm ^Two ))
You. That is, the one-way pressure-resistant packing 6a is
Flow from one liquid chamber 1a to one-way pressure-resistant packing 6a, 6b
Prevents body leakage and allows one-way pressure-resistant packing 6a, 6b
From the first liquid chamber 1a to the first liquid chamber 1a. Unidirectional pressure resistance
Similarly, the packing 6b is also one-way pressure-resistant from the second liquid chamber 1b.
For preventing fluid leakage between the packings 6a and 6b.
Things. The pressure-resistant O-rings 7a and 7b are
Between the first and second liquid chambers 1a.
Pressure resistance from both directions (maximum receiving pressure of about 4
9MPa (500kg / cm ^Two )). Further, the piston device in the present embodiment
, The unidirectional pressure-resistant packing 6a of the clearance 5 and the pressure resistance
The space between the O-ring 7a and the clearance 5
First into the space between the pressure O-ring 7a and the pressure-resistant O-ring 7b
Pressure adjusting mechanism for introducing the fluid in the liquid chamber 1a while reducing the pressure in a stepwise manner.
The pressure regulating device 8 is provided. Further, this pressure adjusting device 8
Conversely, when the pressure in the first liquid chamber 1a is reduced,
Unidirectional pressure-resistant packing 6a and pressure-resistant O-ring 7a
And the pressure-resistant O-ring 7a of the clearance 5
The fluid in the space between the pressure O-ring 7b and the pressure
Is to escape. As shown in FIG. 2, the pressure adjusting device 8 has four
Check valves 9a, 9b, 9c, 9d are provided.
Check valves 9a, 9b, 9c, 9d
Check balls 10a, 10b, 10c as valve bodies,
10d and springs 11a, 11b, 11c, 11
d. The first liquid chamber 1a and check valve 9a
The passage 12a communicates with the passage 12a.
9MPa (400kg / cm ^Two ) Of the spring 11a
It is closed by the pressed check ball 10a. H
Check valve 9a and check valve 9b are connected to flow path 12b.
The flow path 12b has a pressing force of about 29 MPa.
(300kg / cm ^Two ) Spring 11b
Is closed by the check ball 10b. The check valve 9b and the check valve
The passage 9c is communicated with the passage 9c by the passage 12c.
Is a pressing force of about 1 MPa (10 kg / cm ^Two ) Spring
Closed by check ball 10c pressed by 11c
It is. Check valve 9c and check valve 9d
The passage 12d communicates with the passage 12d.
MPa (10 kg / cm ^Two ) Pressed by spring 11d
The check ball 10d is closed. Check
The valve 9d and the first liquid chamber 1a communicate with each other through a flow path 12e.
Is done. Further, the unidirectional pressure-resistant package of the clearance 5 is provided.
The space between the kin 6a and the pressure-resistant O-ring 7a and the check bar
The valve 9a is communicated with the lube 9a by a flow path 12f, and a clearance is provided.
5 between the pressure-resistant O-rings 7a and 7b
And the check valve 9b are communicated by a flow path 12g.
You. The check valve 9a and the check valve 9c are flow paths.
It is communicated by 12h. Next, the operation of the piston device having the above configuration will be described.
The description will be made with reference to FIGS. FIG.
Explanatory diagram showing the operation of the piston device at the time of pressurization, FIG.
Shows the operation of the piston device of FIG. 1 at the time of pressure reduction.
FIG. When the piston device is slid under pressure, the fluid line 4
The maximum rise pressure is about 98MPa (1000kg / cm
^Two When oil as a fluid enters the first liquid chamber 1a,
The stone head 2 is pushed and the piston rod 3 moves the work.
The operation load is applied, and the pressure of the first liquid chamber 1a starts to increase.
The pressure of the first liquid chamber 1a is about 39 MPa (400 kg / cm
^Two ), The spring 11a is connected to the spring 11a as shown in FIG.
About 39MPa (400kg / cm ^Two )
Check ball 10a is pushed, and oil flows through flow path 12a.
It flows into the check valve 9a. At the same time, the spring
About 29 MPa (300 kg / cm ^Two ) Press
The check ball 10b is also pushed and passes through the flow path 12b.
Then, the oil flows into the check valve 9b. The oil flowing into the check valve 9a is
12f, one-way pressure-resistant packing 6 of clearance 5
a into the space between the pressure-resistant O-ring 7a. This and
The check valve 9a and the one-way pressure-resistant packing 6
a in the space between the pressure-resistant O-ring 7a and the first liquid
The pressure of the spring 11a is about 39M from the pressure in the chamber 1a.
Pa (400 kg / cm ^Two ) Works only after subtracting)
You. The oil flowing into the check valve 9b is
2 g, withstand pressure O-ring 7 a of clearance 5 and withstand pressure
It flows into the space between the O-ring 7b. At this time,
Pressure valve 9b and withstand pressure O-ring 7a and withstand pressure O-ring
Pressure in the space between the check valve 9a
From the pressure of about 29 MPa (3
00kg / cm ^Two ) Works by subtracting). Further, oil flows into the check valve 9a.
The pressure inside the check valve 9a is about 59 MPa (600
kg / cm ^Two ), The check valve 9b
Pressure is about 29MPa (300kg / cm ^Two )
The pressing force of the pulling 11b is about 29 MPa (300 kg / c
m ^Two ) Is added and about 59 MPa (600 kg / c
m ^Two Press the check ball 10b with the pressing force
The valve 9b is closed. And the pressure in the first liquid chamber 1a.
Is about 98MPa (1000kg / cm ^Two ) Is reached
The pressure inside the check valve 9a is about 59 MPa (60
0kg / cm ^Two ), And the pressing force of the spring 11a is approximately
39MPa (400kg / cm ^Two ) Is added and about 9
8MPa (1000kg / cm ^Two Check by pressing force
Press the ball 10a and close the check valve 9a. On the other hand, the check valve 9d is connected to the first liquid chamber 1a.
98MPa (1000kg / cm ^Two ) Pressure and
The pressing force of the spring 11d is about 1 MPa (10 kg / cm
^Two ), And the inside of the check valve 9a from the flow path 12d side.
About 59MPa (600kg / cm ^Two ) Under pressure
Therefore, the check ball 10d is approximately 40 MPa (410
kg / cm ^Two ) And closes the check valve 9d
ing. The check valve 9c is about 59 from the side of the flow path 12d.
MPa (600 kg / cm ^Two ) Pressure and spring 11
c of about 1 MPa (10 kg / cm ^Two )
Approximately 29 MPa (300 kg / cm ^Two )of
Check ball 10c is about 30MP
a (310 kg / cm ^Two ) Is pressed by the check valve
9c is closed. In such a state, each packing is received.
The one-way pressure-resistant packing 6 a is applied to the first liquid chamber 1.
a pressure of about 98MPa (1000kg / cm ^Two ) To
About 59 MPa (600 kg / cm
^Two ), The balance is about 39 MPa (4
00kg / cm ^Two ) Pressure only. Similarly, withstand pressure
The O-ring 7a has a pressure of about 59 MPa (60
0kg / cm ^Two ) From the channel 12g side about 29MP
a (300 kg / cm ^Two ) To counter pressure.
About 29MPa (300kg / cm ^Two ) Pressure only
I can't. The pressure-resistant O-ring 7b has a pressure of about 2 on the side of the flow path 12g.
9MPa (300kg / cm ^Two ). Also, at the same time
Between each packing, ie, one-way pressure-resistant packing 6a
Withstand pressure O-ring 7a and withstand pressure O-ring 7a
Oil is supplied between the O-ring 7b and the O-ring 7b.
Therefore, the sliding surface does not run out of oil during this pressurized sliding. On the other hand, when the piston device slides under reduced pressure,
The oil is discharged from the first liquid chamber 1a through the first liquid chamber 1a.
The pressure of 1a begins to drop. When the pressure of the first liquid chamber 1a is about 5
8MPa (590kg / cm ^Two ), The sp
The pressing force of the ring 11d is about 1 MPa (10 kg / cm ^Two )
Is added to the pressure of about 59 MPa (600
kg / cm ^Two ), The check valve 9d opens
To release the pressure on the side of the flow path 12d. The pressure on the side of the flow path 12d is
About 28MPa (290kg / cm ^Two ),
Similarly, the check valve 9c is opened and the pressure on the side of the flow path 12c is
Let go. Thus, the reciprocating motion of the cylinder device is performed.
When the pressure in the first liquid chamber 1a increases again, the above operation is performed.
Repeated. In addition, when sliding under reduced pressure, the inside of the second liquid chamber 1b is
Pressure is sufficient to return the piston head 2.
Since high pressure is not applied to the one-way pressure
Do not use. Therefore, the pressure adjustment mechanism 8 in the present embodiment
Is a maximum rise pressure of about 98 MPa (1000 kg / c
m ^Two ) Is provided only on the first liquid chamber 1a side pressurized with oil.
It is not necessary to provide on the second liquid chamber 1b side. In this embodiment, the piston
Withstand pressure only from the direction of the first liquid chamber 1a outside the sliding surface of the pad 2
Since the one-way pressure-resistant packing 6a showing the property is used,
When the pressure in the first liquid chamber 1a decreases during the pressure reduction sliding,
Oil leaks from the directional pressure-resistant packing 6a to the first liquid chamber 1a.
Therefore, the flow path 12d does not need to pass through the check valve 9d.
Side pressure can be relieved. Conversely, check valve
9d, the one-way pressure-resistant packing 6a
Even if a normal packing such as the O-rings 7a and 7b is used,
Good. In the above description, the pressure regulating device 8
Although the structure is embedded in the piston head 2,
The pressure adjusting device 8 is unitized to form a pressure adjusting unit as shown in FIG.
It is also possible to use the unit 13. FIG. 5 shows another embodiment of the present invention.
FIG. 2 is a detailed view of a part A of FIG. 1 showing an embodiment. In FIG. 5, the pressure adjusting unit 13 is
Check valves 9a, 9b,
9c, 9d and flow paths 12a, 12b, 12c, 12
The unit including d, 12e, and 12h is unitized to reduce the outer diameter.
It is cylindrical and is attached to the piston head 2 by the assembling screw 16
It is made detachable. In addition, the pressure adjustment unit 13
On the outer periphery, flow paths 14a, 14b and O-rings 15a,
15b. The O-ring 15a communicates with the first liquid chamber 1a.
This is for blocking the road 14a. O-ring 15
b is for shutting off the flow path 14a and the flow path 14b
It is. The flow paths 14a and 14b are
It is formed so as to surround the outer circumference, and
Check valve 9a, check valve 9a, 9
This is a fluid passage for communicating b. The flow path 14
a, 14b are the pressure adjusting units 13 by the assembling screws 16;
From the width of each of the flow paths 12f and 12g in the screwing direction
Is also widely formed. Thereby, the pressure regulation unit 13
Pressure adjusting unit when
No matter which direction the 13 is facing, some misalignment
Even if there is, the flow path 12a and the flow path 12f, and the flow path 14b and the flow path
12g are communicated with each other. As described above, the pressure adjusting device 8 is detachably attached to the unit.
By adjusting the pressure adjusting unit 13 to
The manufacture and processing of the seal structure becomes easy, and economical and general
Advantages such as usability are also obtained. In the example shown in FIG.
, The pressure adjustment unit 13 has a piston
It is attached to the head 2, but it also has a flange etc.
It is also possible to use and attach. In the description of the present embodiment, the pressure regulation
Check mechanism 10a-10d and spring
Check valves 9a to 9d using 11a to 11d
The pressure regulating mechanism is generally used as an example.
Can be replaced with the one used for fluid pressure adjustment
Noh. For example, combining a conical valve with a spring
That regulates pressure in proportion to the piston pressure receiving area
And any of those by adjusting the spring pressure
It is possible to do. Among them, compared to the piston pressure receiving area
For example, if a pressure regulator is used, it will be proportional to the pressure of the liquid chamber.
And depressurize to exert the function of the seal structure of the present invention.
It is possible. The seal structure of the present invention as described above has a thrust
For a cylinder device that operates at thousands or tens of thousands tons
Even if the distance between the piston and cylinder is very small,
Between the pressure-resistant packing 6a and the pressure-resistant O-ring 7a, the pressure-resistant O-ring
7a and withstand voltage O-ring 7b, one direction with withstand voltage O-ring 7b
The space volume between the pressure-resistant packings 6b is very small.
Therefore, the pressure regulation mechanism can be made small and unitized.
In this case, the assembling work can be easily performed. In this embodiment, the cylinder 2 is
Single cylinder double acting cylinder with high pressure in the first liquid chamber 1a
Although the operation at the time is described, the first liquid chamber 1a and the
For civil engineering to operate each of the second and first liquid chambers 1b at high pressure
It can also be applied to piston devices such as hydraulic heavy machinery.
You. FIG. 6 shows a piston for operating the present invention bidirectionally at high pressure.
FIG. 7 is a schematic configuration diagram showing an example applied to an apparatus, and FIG.
FIG. 4 is a detailed view showing the same configuration as that shown in FIGS.
Are denoted by common reference numerals. The piston device shown in FIG.
Pressure-resistant packing 6a, pressure-resistant O-rings 7a and 7b, and pressure regulation
The device 8 is connected to the first sliding part between the cylinder 1 and the piston head 2.
Not only in the first liquid chamber 1a but also in the second liquid chamber 1b
It is a digit. The cylinder 1 and the piston rod 3
Similarly, the one-way pressure-resistant packing 6 shown in FIG.
a, the pressure-resistant O-rings 7a and 7b and the pressure regulator 8
It is provided as shown in FIG. Cylinder 1 and piston
The pressure adjusting device 8 of the sliding part with the rod 3 is
Unidirectional pressure-resistant packing with clearance 5a from ton rod 3
Between the housing 6a and the pressure-resistant O-ring 7a, and clear
Of the pressure-resistant O-rings 7a and 7b of the lance 5a
The fluid in the second liquid chamber 1b is decompressed stepwise to the space between
Is what you enter. Thus, the second liquid chamber 1b operates at a high pressure.
When working, the cylinder 1 facing the second liquid chamber 1b and the piston
Sliding surface with the piston head 2 and the cylinder 1 and piston lock
One-way pressure-resistant packing 6a for each sliding surface with
Pressure received by pressure O-ring 7a and pressure-resistant O-ring 7b
Is reduced by the operation of the pressure adjusting device 8 as described above.
Therefore, the second liquid chamber 1b is connected to each packing (one-way pressure-resistant packing).
Or higher than the pressure resistance of the packing 6a and the pressure-resistant O-rings 7a, 7b).
Even if pressurized with the pressure of
Pressure less than the withstand pressure of the
High-pressure fluid is introduced into the first liquid chamber 1a and the second liquid chamber 1b, respectively.
And the piston device can operate stably. Further, the pressure adjusting device 8 in the present embodiment
For pistons, cylinders, rods, etc. that slide under fluid pressure
However, the present invention can be applied to a single cylinder double acting type or a ram type. FIG.
Is an outline showing an example in which the present invention is applied to a ram-type piston device.
FIG. 9 is a detailed view of a portion C in FIG. The ram type piston device shown in FIG.
Fixed to the upper part of the support / slide shaft 22 on the base plate 21.
A ram cylinder 24 integrated with the fixed beam 23,
A ram piston 25 that slides facing the ram cylinder 24
It is constituted by and. The ram piston 25 has a support
A movable beam 26 that slides up and down along a slide shaft 22
Is fixed. The movable beam 26 is connected to the ram cylinder 24 and the ram
Connected to cylinder chamber 27 formed between piston 25
By introducing high pressure fluid into the fluid line 28
Work material descended and placed on the fixed base plate 21
Press (not shown). In addition, the movable beam 26 and the fixed base
The movable beam 26 is raised between the source plate 21 and the base plate 21.
Piston device 29 is provided. As shown in FIG. 9, the ram cylinder 24
As shown in FIG.
Pressure packing 6a, pressure-resistant O-rings 7a, 7b and pressure regulating unit
A knit 30 is provided. The pressure adjustment unit 30 is
The fluid introduced from the cylinder chamber 27 via the flow path 31 is
Clearance between ram cylinder 24 and ram piston 25
5b between the unidirectional pressure-resistant packing 6a and the pressure-resistant O-ring 7a.
The space between them and the pressure-resistant O-ring 7a of the clearance 5b
Into the space between the pressure-resistant O-ring 7b
This is a unitized pressure adjustment mechanism. Channel 12
f, 12 g, 31 ram cylinder 24 and pressure regulating unit 3
0, the respective flow paths 12f, 12g, 3
O-rings 32a, 32a to prevent fluid leakage from
b, 32c are provided. Even in such a configuration, the cylinder chamber 2
Each packing (one-way pressure-resistant packing 6a and pressure-resistant packing
High pressure fluid is introduced at a pressure higher than the pressure resistance of the O-rings 7a, 7b).
When it enters, it passes through the clearance 5b from the cylinder chamber 27.
Is introduced by the action of the pressure regulating unit 30
The pressure is reduced stepwise, and the one-way pressure-resistant packing 6a and the pressure-resistant O phosphorus
And the pressure-resistant O-ring 7a and the pressure-resistant O-ring.
To the space between the ring 7b. Therefore,
As with, each packing only has a pressure less than
High-pressure fluid in the cylinder chamber 27
And stable operation of the piston device is possible. According to the present invention, the following effects can be obtained.
Can be. (1) Clear between cylinder and piston
Multiple packings to seal the lance on the sliding surface of the piston
And a cylinder between the multiple packings
A pressure regulation mechanism is provided to introduce and reduce the pressure of the fluid in the room in stages.
The packing between the cylinder and the piston
The pressure difference between the clearances on both sides of the
Even if the piston is operated at a pressure higher than the pressure
The deformation of the packing causes the clearer between the cylinder and piston.
It does not get inside the dance. Also, juxtaposed
Fluid is supplied between multiple packings,
Gasket comes in close contact with the cylinder and runs out of fluid on the sliding surface.
Never wake up. Therefore, heat and wear of the sliding part
Generation is prevented and the piston operates stably even under high pressure.
Becomes possible. (2) The pressure adjusting mechanism is further provided in the cylinder chamber.
Between the multiple packings arranged side by side when the pressure of
By discharging the body, the pressure in the first liquid chamber is reduced.
Is introduced between the multiple packings
Pressure can be released, and packing can be performed during pressure reduction.
Pressure acting on the piston
Pressure sliding can be performed more smoothly. (3) Rubber or elastic as packing
By using a toma type, rubber elasticity
To securely close the clearance between the cylinder and piston.
And leakage of fluid can be prevented. (4) Whether the packing is between a plurality of packings
Decompression by providing a function that allows fluid leakage
In some cases, fluid leaks from between multiple packings and
Increased pressure introduced between the multiple packings
Release and make the piston slide smoothly under reduced pressure.
It becomes possible.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing a configuration of a piston device according to an embodiment of the present invention. FIG. 2 is a detailed view of a portion A in FIG. FIG. 3 is an explanatory view showing an operation of the piston device of FIG. 1 at the time of pressurization. FIG. 4 is an explanatory diagram showing an operation of the piston device of FIG. 1 at the time of pressure reduction. FIG. 5 is a detailed view of a part A of FIG. 1 showing another embodiment of the present invention. FIG. 6 is a schematic configuration diagram showing an example in which the present invention is applied to a piston device that operates bidirectionally at a high pressure. FIG. 7 is a detailed view of a portion B in FIG. 6; FIG. 8 is a schematic configuration diagram showing an example in which the present invention is applied to a ram-type piston device. 9 is a detailed view of a part C in FIG. [Description of Signs] 1 Cylinder 1a First liquid chamber 1b Second liquid chamber 2, 2a Piston 3 Rod 4a, 4b Fluid line 5 Clearance 6a, 6b, 6c Unidirectional pressure-resistant packing 7a, 7b Pressure-resistant O-ring 8 Pressure regulator 9a , 9b, 9c, 9d Check valves 10a, 10b, 10c, 10d Check balls 11a, 11b, 11c, 11d Springs 12a to 12h Flow paths 13 Pressure regulating units 14a, 14b Flow paths 15a, 15b O-ring 16 Assembly screw 21 Fixation Base plate 22 Support / slide shaft 23 Fixed beam 24 Ram cylinder 25 Ram piston 26 Movable beam 27 Cylinder chamber 28 Fluid line 29 Piston device 30 for ascending 30 Pressure regulating unit 31 Flow path

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-3-164597 (JP, A) JP-A-11-166510 (JP, A) JP-A-7-224806 (JP, A) JP-A-60-1985 245876 (JP, A) Fully open 1988-75603 (JP, U) Fully open 3-107571 (JP, U) Fully open 1986-81061 (JP, U) Fully open, 62-155592 (JP, U) Japanese Utility Model Showa 61-88072 (JP, U) Japanese Utility Model Showa 58-19164 (JP, U) Japanese Utility Model Showa 58-2348 (JP, U) Japanese Utility Model Showa 57-49902 (JP, U) (58) (Int.Cl. ⁷ , DB name) F15B 15/14 345 F16J 9/12 F16J 10/00 F16J 15/16

Claims (1)

(57) [Claim 1] A cylinder, and a piston slidably opposed to the cylinder, and a cylinder chamber formed between the cylinder and the piston is pressurized with a fluid. A seal structure for a piston device that obtains a job, wherein the rubber or rubber seals a clearance between the cylinder and the piston.
A plurality of stoma-based packings are arranged in parallel on the sliding surface between the cylinder and the piston, and when the fluid in the cylinder is pressurized, the pressurized fluid in the cylinder chamber is depressurized stepwise, Among the plurality of clearances defined by the packing, the pressure is reduced stepwise in order to the clearance located far from the clearance located near the cylinder chamber.
The pressure regulating mechanism for introducing the fluid is provided, further, the pressure regulating mechanism, characterized in that when said cylinder chamber of the fluid is decompressed, and discharges the fluid in a plurality of said clearance to the cylinder chamber The seal structure of the piston device.