JPH0759358B2 - Gas cushion - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cushion member used for die sheet metal stamping or other various manufacturing processes, and in particular, a high pressure gas such as high pressure nitrogen gas is sealed inside to use the reaction force to cushion it. The present invention relates to a gas cushion that exerts its action.

[0002]

2. Description of the Related Art As a conventional gas cushion of this kind,
As shown in FIG. 8, a piston type cylinder is often used. That is, the piston 2 is fitted into the cylinder body 1 and the sliding contact member 3a made of sponge, felt or the like is provided as a separate member on the outer peripheral surface of the piston 2 as lubrication irrelevant to the mounting direction of the cylinder body 1. Along with mounting the sealing material 3b, the sliding contact material 3a is impregnated with lubricating oil so that the sealing material 3b has lubricity and sealing performance.
High pressure gas is sealed in the piston side pressure chamber 4 inside, and the pressing load applied to the tip end portion of the piston rod 5 is received by the reaction force of the high pressure gas. This conventional device has a simple structure. However, the lubricating oil impregnated in the sliding contact material 3a is scattered or consumed due to a rapid sliding motion at a high speed during use, and so-called oil shortage causes a seal breakage in a short period of time. A breathing action is generated between the rod side pressure chamber 6 of the cylinder body 1 and the outside, and this breathing action causes dust to enter the inside of the cylinder body 1 and causes damage to the seal and sliding parts. Was there. In the figure, 7 is an air vent.

[0003]

SUMMARY OF THE INVENTION Therefore, according to the present invention, the high pressure gas that is enclosed without causing oil shortage even when used at a high speed for a long period of time regardless of the mounting direction of the cylinder body.
The sealing performance of the
The aim is to propose a gas cushion of this kind , which has a long life and which does not give rise to the abovementioned respiratory effects.

[0004]

In order to solve the above-mentioned problems, the present invention will be described with reference numerals shown in the embodiments,
In claim 1, the cylinder body 10 has a hollow ram 1
1 and a piston 12 at its tip end are air-tightly fitted with a ram-shaped piston 13 with a sealing material 27 interposed therebetween, and a cylinder-side oil supply pipe 16 is connected to the piston 12 through the piston-side cylinder cover 14 and the ram-side cylinder cover 15. penetrating and arranged piston-side pressure chamber 17 through the oil pipe 16
And a ram side pressure chamber 18, a cylinder side oil feed passage 19 is formed, the cylinder side oil feed passage 19 passes through the seal material accommodating chamber 31 on the way, and the piston side inside the hollow ram 11 is formed. ram side Okuaburaro 22 which communicates over the hollow chamber 21 Doo end wall 12a and the ram-side end wall 12b and through the oil pipe 20 is disposed a ram-side oil feed pipe 20 for the ram-side pressure chamber 18 and the hollow ram 11 the <br/> co forming a communication between the hollow chamber 21 and the piston-side pressure chamber 17 of the middle air ram 11, Thus formed by sealing the high pressure gas G and the lubricating oil O in the cylinder body 10 The configuration is adopted.

Further, in claim 2, the both oil feed passages 1
Check bars that open and close alternately at the 9 and 22 ends due to their own weight
The structure according to claim 1, which is formed by charging the lubes 23 and 24.
Is used.

Further, in claim 3 , claim 1 or
In the configuration described in 2, the piston 12 through which the cylinder side oil feed pipe 16 penetrates is attached to the hollow ram 11 in a slightly floating state in the axial direction and the radial direction.

Further, in claim 4 , claim 1 , 2
Alternatively, in the configuration described in 3, the check for opening the piston 12 to the ram side pressure chamber 18 through the ram side oil passage 22 only when the piston 12 receives the overload pressure from the piston side pressure chamber 17. The configuration in which the valve 39 or the check packing 26 is attached is adopted.

[0008]

According to the first aspect of the present invention, when the hollow ram 11 receives the pressure applied to the die during press working, and the hollow ram 11 descends against the reaction force of the high pressure gas in the cylinder body 10. , The pressure in the piston side pressure chamber 17 is the ram side pressure chamber 1
Since it is higher than the pressure of 8, the lubricating oil of the piston side pressure chamber 17 in the cylinder body 10 is pumped to the ram side pressure chamber 18 via the cylinder side oil passage 19 due to the pressure difference between the two chambers. During this pressure-feeding, the lubricating oil is stored in the seal material storage chamber 3
After passing through 1, the lubricating oil is supplied to the sealing material (gland packing 27) housed therein to make it wear resistant, and then the lubricating oil is supplied from the cylinder side oil supply passage 19 to the ram side pressure chamber 18 Is sent out in a jet form. In the process in which the hollow ram 11 is released from the mold pressure and rises, the pressure in the ram side pressure chamber 18 is higher than the pressures in the hollow chamber 21 of the hollow ram 11 and the piston side pressure chamber 17 communicating with it. Lubricating oil in the ram side pressure chamber 18 is blown out into the hollow chamber 21 by pushing up the check valve 24 via the ram side oil feed passage 22 near the extension end of the hollow ram 11, and the spray oil is sprayed. By being sprayed on the inner peripheral surface 11b of the cylinder, the lubricating oil itself and the cylinder body 10 are cooled from this surface through the hollow ram 11 which is a sliding member, and then the piston side pressure chamber communicating therewith is exerted. Lubricating oil is returned to 17.

Further, in claim 1, the hollow ram 11,
Since the high pressure gas is filled in all of the ram side pressure chamber 18 and the piston side pressure chamber 17 and all of these spaces are used, the compression ratio at the time of operation of the ram type piston 13 can be reduced and at the same time, the ram side. The pressure chamber 18 and the piston side pressure chamber 17 are connected to the cylinder side oil passage 19 and the ram side oil passage 2 respectively.
Even though it receives pressure resistance due to 2 and 2, since it is in a communication state alternately, no breathing action occurs between the ram side pressure chamber 18 and the outside.

Further, in claim 1, when the ram type piston 13 is returned to the extended state, the lubricating oil remaining in the ram side pressure chamber 18 at the extended end thereof functions as a cushion.

Further, according to the second aspect , the check valves 23 and 24 are respectively inserted into the respective ends of the cylinder side oil feed passage 19 and the ram side oil feed passage 22, and when the valve is upright as shown in FIG. The cylinder side check valve 23 is positioned below by its own weight to maintain the cylinder side oil feed passage 19 in an open state, and the ram side check valve 24 is attached to the ram side oil feed passage 22.
5, the ram-side check valve 24 keeps the ram-side oil feed passage 22 open when the ram-type piston 13 is in the inverted position, and the cylinder-side check valve 23 holds the cylinder-side oil feed. The passage 19 can be closed to ensure the same lubricating oil circulation path as in the upright state even in the above inverted state.

According to the second aspect of the present invention , both check valves 23 and 24 have the function of reliably maintaining the differential pressure between the piston side pressure chamber 17 and the ram side pressure chamber 18. That is, taking the upright state of FIG. 1 as an example, as described above, the pressure in the piston side pressure chamber 17 becomes higher than that in the ram side pressure chamber 18 when the ram type piston 13 descends, but when the ram side pressure chamber 18 rises, the ram side pressure chamber 18 increases. If the chamber 18 becomes higher, the ram-side check valve 24 moves upward against its own weight, and the ram-side oil passage 22 is opened until the normal differential pressure state is reached.

Since a constant differential pressure can be guaranteed between the pressure chambers 17 and 18 regardless of the speed of movement of the ram piston 13, the lubricating oil can always be satisfactorily circulated.

[0014] In claim 3, the piston 12 slightly in the mobile developing in the radial direction by the occurrence or the external load of the rotational action of the hollow ram 11 between the cylinder side oil feed pipe 16 extending therethrough and the piston 12 of Even if there is a deviation, the piston 12 is in a floating state in the axial direction and the radial direction, so that stress can be prevented from occurring between them.

In the fourth aspect, the ram type piston 13
When the piston 12 receives an excessive load from the piston side pressure chamber 17 due to the rapid movement of the piston side, this overload pressure is released to the ram side pressure chamber 18 side, and an excessive pressure difference is generated between the pressure chambers 17 and 18. Do not wake up, so pressure chambers 17, 18
It is possible to always guarantee a constant differential pressure in the meantime and avoid a temporary increase in the compression ratio.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, a cylinder body 10 is provided with a ram-shaped piston 13 including a hollow ram 11 and a piston 12 at its tip end in a seal housing chamber 31 of the cylinder body 10. It is fitted airtightly via 27.
The piston side cylinder cover 14 of the cylinder body 10 is provided with an oil sump 28a, and when used in an inverted state as described later (see FIG. 5), the oil sump 28a is retained on the ram side end wall 12b of the hollow ram 11. 28b is formed. And the piston side cylinder cover 14 and the ram side cylinder cover 1
5, the cylinder side oil feed pipe 16 is connected to the piston 1
It is attached through 2. The piston side cylinder cover 14 has an oil sump 28a and the cylinder side oil supply pipe 1
6 is formed, and an oil passage 30 that connects the ram side pressure chamber 18 and the cylinder side oil feed pipe 16 is formed in the ram side cylinder cover 15, and the oil passage 30 is formed. Along the way, it communicates with a chamber 31 for accommodating the sealing material 27, passes through the seal accommodating chamber 31, and passes through the ram side pressure chamber 18
It is designed to communicate with. Therefore, the oil passage 29, the cylinder side oil feed pipe 16, the oil passage 30, and the seal accommodating chamber 31 form the cylinder side oil feed passage 19 that communicates between the oil sump 28 a of the piston side pressure chamber 17 and the ram side pressure chamber 18. To do.

The piston 12 is formed by an annular member, and the piston 12 is loosely sandwiched between the hollow ram 11 and the piston side end wall 12a as shown in FIG. Is formed slightly larger than the outer diameter of the outer peripheral groove 40 of the piston side end wall 12a, so that the piston 12 is slightly floating in the axial direction and the radial direction with respect to the hollow ram 11 (floating state).
Is attached to. Further, the piston 12 has a built-in check valve 39 which can be opened only from the piston side pressure chamber 17 to the ram side pressure chamber 18, or can be bent on the outer peripheral surface of the piston 12 only to the ram side pressure chamber 18 side. Sealing material 26
Is provided.

Further, the end wall 12 of the hollow ram 11 on the piston side.
The ram side oil feed pipe 20 is attached to the a and the ram side end wall 12b, and one end of the ram side oil feed pipe 20 opens to the ram side pressure chamber 18 and the other end to the ram side oil feed pipe 20 across the piston side end wall 12a and the piston 12. An oil passage 32 communicating with the ram side end wall 12b is formed, and an oil passage 33 having one end communicating with the ram side oil feeding pipe 20 and the other end opening to the hollow chamber 21 of the hollow ram 11 is formed. Therefore, the oil passage 32 and the concave groove 4
0, the ram side oil supply pipe 20 and the oil passage 33 are the ram side pressure chamber 1
A ram-side oil passage 22 is formed that connects the hollow cylinder 21 and the hollow chamber 21 of the hollow ram 11. Furthermore, the piston side end wall 12 a
A communication hole 25 that communicates the hollow chamber 21 and the piston-side pressure chamber 17 is formed therein, so that the hollow chamber 21 operatively forms a part of the piston-side pressure chamber 17.

Then, check valves (ball valves) 23 and 24 for alternately opening and closing the oil feed passages 19 and 22 by their own weights are inserted at the ends of the oil feed passages 19 and 22, respectively.

Reference numerals 34, 35 and 36 are known sliding members for reducing the frictional resistance of the sliding surface. Again 37
Is a dust seal material, 38 is a safety valve for a melting tap, 41, 4
2 is a check valve for gas charging and a plug.

However, the oil sump 2 in the cylinder body 10
8a is filled with a small amount of lubricating oil O and is filled with high-pressure nitrogen gas G.

2 to 4 show the operating state of the cylinder body 10 when it is upright. First, as shown in FIG. 2, the ram-shaped piston 13 receives a high pressure inside the cylinder body 10 by receiving an external load from the upper part. When it descends against the reaction force of the gas G, the lubricating oil O in the oil sump 28a passes through the cylinder-side oil supply passage 19 due to the differential pressure between the piston side pressure chamber 17 and the ram side pressure chamber 18, and passes through the cylinder side oil supply passage 19. 31 and the lubricating oil O is supplied to the sealing material 27 here, and then the lubricating oil is sent out from the oil passage 30 to the ram side pressure chamber 18, and the pressure chamber 18
Lubricating oil G is retained in the. As described above, the lubricating oil is supplied to the seal material 27 every time the piston 13 descends, and therefore oil shortage does not occur. As shown in FIG. 3, when the ram type piston 13 reaches the lowermost end, the lubricating oil O stays in the ram side pressure chamber 18. Next, when the piston 13 rises, the pressure in the ram side pressure chamber 18 becomes higher than that in the piston side pressure chamber 17, and the pressure in the ram side pressure chamber 18 is first set in the cylinder side oil passage 19 due to the pressure difference between the two. Through the piston-side pressure chamber 17, the lubricating oil also passes through the ram-side oil feed passage 22, pushes up the check valve 24 above it against its own weight, and from the tip of the oil passage 33 to the hollow ram 11 Lubricating oil O is sent out into the hollow chamber 21 of the hollow ram 11, and the atomized lubricating oil is fed to the inner peripheral surface 11 of the hollow ram 11.
The lubricating oil returns to the oil reservoir 28a of the piston side pressure chamber 17 through the communication hole 25 while exerting an action of cooling the lubricating oil itself and the cylinder body 10 through the hollow ram 11 by being blown to the b. It will be. Then, as shown in FIG. 4, when the ram-type piston 13 reaches the vicinity of the uppermost end, the lubricating oil O retained in the ram-side pressure chamber 18 plays the role of a cushion material, and the impact at the return end of the piston 13 is exerted. Will be alleviated.

The piston 12 of the ram type piston 13 moves up and down along the cylinder side oil feed pipe 16 penetrating the ram type piston 13. If the piston 12 and the hollow ram 11 are integrally formed rigidly at this time. , Ram type piston 1
When a slight rotational force or swinging occurs when lifting and lowering 3, the interference of the piston 12 causes harmful stress to the cylinder side oil feed pipe 16 and damages the oil feed pipe 16.
According to an embodiment of the present invention, as shown in FIG.
2 is formed in a slightly floating state in the axial direction and the radial direction with respect to the hollow ram 11, so that the ram type piston 13
Can be smoothly moved up and down without receiving the harmful restraining force of the cylinder side oil feeding pipe 16.

Further, as shown in FIG. 1, a ram type piston 1
When the internal pressure of the piston side pressure chamber 17 becomes excessive due to the sudden downward external force of 3, the check valve 39 opens or the check packing 26 having a substantially U-shaped cross section is provided on the ram side pressure chamber 18 side. The excess pressure in the pressure chamber 17 is flexed to be released to the ram side pressure chamber 18 through the ram side oil feed passage 22, so that a temporary increase in the compression ratio can be alleviated.

The check valve 2 is alternately opened and closed by its own weight at the piston cover side end of the cylinder side oil supply passage 19 and the hollow ram side end of the ram side oil supply passage 22, respectively.
1, the cylinder side check valve 23 opens the cylinder side oil passage 19 to allow the flow of lubricating oil, while the ram side check valve 24 closes the ram side oil passage 22. The pressure of the hollow chamber 21 of the hollow ram 11 is prevented from entering the ram side oil supply passage 22 when the ram type piston 13 descends.

As shown in FIG. 5, when the ram-type piston 13 is used in a downward inverted state, it operates in the opposite manner. That is, in this inverted state, the lubricating oil stays in the oil sump 28b at the bottom of the hollow chamber 21 of the ram-type piston 13, and when the ram-type piston 13 contracts from the expanded state, the position shown in FIG. As shown in FIG. 7, the lubricating oil is jetted out to the ram side pressure chamber 18 through the ram side oil feed passage 22 and stays in the pressure chamber 18 and then extends from the contracted end as shown in FIG. First, the pressure in the pressure chamber 18 first flows through the ram side oil passage 22 to the hollow chamber 21, and then the lubricating oil also passes through the cylinder side oil passage 19 to the piston side pressure chamber 17 of the check valve 23. It is sent out against its own weight, passes through the communication hole 25, and the oil sump 28 in the hollow ram 11
It will be returned to b. Then, on the way, the lubricating oil is supplied to the sealing material 27 through the sealing material accommodation chamber 31.

[0027] Therefore, Oite to an embodiment of the present invention in an inverted state, can be freely used as long as the pair of check valves 23 and 24 opened and closed the Okuaburaro 19, 22 under its own weight.

In the present invention, a hollow ram type cylinder 13 is also adopted, and together with the hollow chamber 21, the cylinder body 1
Since the high pressure gas G is filled in all the space portions in 0 and all of them are used for the compression work of the high pressure gas, the compression ratio of the high pressure gas can be suppressed to a low level. In other words, this is an improvement in performance. It can contribute to downsizing of the device.

[0029]

According to the first aspect of the present invention, it is possible to reliably supply the lubricating oil to the seal material on the sliding surface of the cushion piston when the cushion piston is actuated, regardless of the mounting direction of the cylinder body. sealing of the high pressure gas is also used for a long time regardless of the slow whether to cause oil shortage is rather name enclosing
Reliability and long life without lowering the filling pressure.
It

Further, since the lubricating oil circulates between the pressure chambers on the piston side and the ram side each time the cushion piston is actuated, only a small amount of lubricating oil needs to be enclosed to exert a sufficient lubricating action. You can

Further, according to the first aspect, it is possible to reduce the compression ratio during the operation of the ram type piston, which can contribute to the improvement of the performance and the downsizing of the apparatus.

According to the first aspect of the present invention, the piston side pressure chamber and the ram side pressure chamber are alternately in communication with each other while receiving pressure resistance by the cylinder side oil feed pipe and the ram side oil feed passage, so that the ram side pressure is maintained. There is no breathing effect between the chamber and the outside, so dust does not enter the cylinder body from the outside, and the dust seal removes the dust adhering to the ram and damages the sliding surface. There is nothing to do.

Further, according to the first aspect, when the ram type piston is returned to the extended state, the lubricating oil remaining in the ram side pressure chamber at the extended end thereof acts as a cushion so as not to give a shock to the device and to reduce noise. There is no occurrence.

Further, according to the first aspect, it can be used not only in the inverted state but also in the diagonally sideways state, and can be used freely according to the working conditions.

Further, according to the second aspect of the present invention, by the action of each check valve provided in both the oil feeding pipes, a constant differential pressure is exerted on the piston side pressure chamber and the ram side pressure regardless of the speed of movement of the ram type piston. The lubricating oil can always be satisfactorily circulated because it can be guaranteed with the chamber.

Further in claim 3, thereby rise to harmful stresses on the cylinder side oil pipeline be slightly upset occurs rotational force to the piston or acting on the hollow ram in the movement course of the ram type piston Without this, the ram piston can be operated smoothly.

[0037] In a further aspect 4, even when the piston an excessive load from the piston-side pressure chamber receives by rapid movement of the ram type piston, and opening the overload pressure to the ram side pressure chamber side As a result, an excessive pressure difference can be prevented from occurring between the pressure chambers, so that a constant pressure difference can be always guaranteed between the pressure chambers, and the cushion performance can be normally maintained.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view of the present invention.

FIG. 2 is an operation explanatory view of the cylinder body of the present invention when it is upright, showing a first step.

FIG. 3 is an operation explanatory view of the second step.

FIG. 4 is an operation explanatory view of the same third step.

FIG. 5 is an operation explanatory view when the cylinder body of the present invention is inverted, showing a first step.

FIG. 6 is an operation explanatory view of the same second step.

FIG. 7 is an operation explanatory view of the third step.

FIG. 8 is a vertical sectional front view of a conventional device.

[Explanation of symbols]

 10 Cylinder Body 11 Hollow Ram 12 Piston 12a Piston Side End Wall 12b Ram Side End Wall 13 Ram Type Piston 14 Piston Side Cylinder Cover 15 Ram Side Cylinder Cover 16 Cylinder Side Oil Pipe 17 Piston Side Pressure Chamber 18 Ram Side Pressure Chamber 19 Cylinder Side Oil supply passage 20 Ram side oil supply pipe 21 Hollow ram hollow chamber 22 Ram side oil supply passage 23 Check valve 24 Check valve 25 Communication hole 26 Check packing 27 Seal material 28a, 28b Oil sump 31 Seal storage chamber 39 Check valve

Claims (4)

[Claims] 1. A ram-shaped piston comprising a hollow ram and a piston at its tip is hermetically fitted to a cylinder body via a sealing material, and a cylinder-side oil supply pipe is provided across the piston-side cylinder cover and the ram-side cylinder cover. thereby forming a cylinder side Okuaburaro communicating over the said piston and the penetrates through the arrangement to the oil pipeline piston-side pressure chamber and the ram pressure chamber, the sealing material in the middle the cylinder side Okuaburaro is It passes through the storage chamber and communicating over the piston end wall and disposed a ram-side oil pipeline over a ram end wall through the oil feed pipe ram-side pressure chamber and the hollow ram of the hollow chamber in the interior of the hollow ram When the ram side oil passage is formed
To communicate a middle empty ram hollow chamber and the piston-side pressure chamber,
Then, a gas cushion in which high pressure gas and lubricating oil are enclosed in the cylinder body. 2. The two oil feed passage ends are alternately alternated by their own weight.
The check valve according to claim 1, wherein the check valve is opened and closed.
Gas cushion. 3. The fixer having a cylinder side oil feed pipe passing therethrough.
The floating ram is suspended in the axial and radial directions in the hollow ram.
The gas bush according to claim 1 or 2, which is attached.
Yon. 4. A piston-side pressure chamber is attached to the piston.
The overload pressure of the ram
Check valve that opens to the ram side pressure chamber through the side oil passage
A case or a check packing is attached.
The gas cushion according to any one of 3 above.