WO1999032815A1 - Device for applying a sealing body by means of radial compression - Google Patents

Abstract

The invention relates to a device for applying a sealing body (21, 22) by means of radial compression in order to seal a first machine part with regard to a second machine part. The invention is provided especially for outwardly sealing a cylinder (12) with regard to a piston rod (11) or a piston, or for inwardly sealing a piston rod or a piston with regard to a cylinder. A ring seal (20) with a sealing body (21, 22) is provided in the first machine part. Said sealing body lies on the second machine part such that it seals. An expandable formed body (23) is located between the sealing body (21, 22) and the first machine part. The formed body has an inner cavity (24) in which a pressure medium is located. The volume of the pressure medium can be increased in order to compensate for wear of the sealing body (21, 22). Means are provided in order to puncture the expandable formed body (23) by means of a hollow needle (26), and in order to feed additional pressure medium into the inner cavity (24).

Description

 Device for the radial pressing of a sealing body

The invention relates to a device for the radial pressing of a sealing body in order to seal a first machine part against a second machine part, in particular for sealing a cylinder against a piston rod or a piston, wherein an annular seal with the sealing body is provided in the first machine part, which is on the second Machine part fits tightly and in which there is an expandable, in particular hose-like structure between the sealing body and the first machine part, which has an interior space in which a pressure medium is located, the volume of the pressure medium being able to be increased to compensate for wear or repositioning of the sealing body.

Pressure devices of the type mentioned above are known, for example from DE 40 18 897 AI, DE 42 10 701 C2 and DE 44 40 895 Cl, and are also referred to herein as Blähring seals. In the present case, wear of the sealing body is not only to be understood as an abrasion of the sealing body but also a material aging shrinkage or a repositioning of the material of the sealing body.

In Blähring seals an expandable structure is used in a seal usually designed as a ring seal, which either itself forms a sealing element or is arranged between the sealing element and the sealing machine part. There is a pressure medium in the interior of the expandable structure, ie either a gas or a liquid. If the seal wears out, additional pressure medium can be introduced into the expandable structure, so that it expands and the wear is therefore compensated for. The sealing medium can be a gas or a gel-like liquid or a gel.

Known seals of this type are relatively expensive because, in particular with moving machine parts, the continuous connection of the expandable structure to a pressure source can only be produced in a complicated manner. The object of the present invention is to further develop a pressing device of the type mentioned at the outset such that this outlay is reduced. In particular, it should be possible to adjust the pressure device only when there is a need, that is, when the seal as a whole is worn out in a predetermined manner.

This object is achieved according to the invention in a pressing device of the type mentioned at the outset in that means are provided in order to pierce the expandable structure by means of a cannula and to introduce further pressure medium into the interior.

The object underlying the invention is completely achieved in this way.

By "injecting" a pressure medium into the interior of the expandable structure, it is achieved that the transfer means are specially designed, in extreme cases through a pointed cannula through which the pressure medium can be introduced into the interior.

The arrangement can alternatively be such that the expandable structure is only pierced when necessary, ie when the specified wear or repositioning has actually occurred; alternatively, however, the expandable structure can also be pierced from the beginning, that is to say already during the assembly of the seal, the seal being set to its desired coefficient of friction during assembly and the pressure medium then being introduced into the expandable structure only when necessary. The advantage of the first-mentioned variant is that the expandable structure is completely intact until the need arises and is therefore completely unaffected by interference. The advantage of the second variant mentioned is that no special means have to be provided in order to carry out the piercing movement of the cannula into the expandable structure if necessary.

Overall, the use of a pointed cannula has the advantage that the damage to the expandable structure is extremely small. With conventional materials for such structures, the punctured skin of the structure closes again on its own, so that both when the cannula remains in the wall of the expandable structure and when the cannula is withdrawn from the wall of the expandable structure, the injury occurring there does not count as Leak works.

Embodiments of the invention are particularly preferred in which the pressure in the interior of the expandable structure is monitored and the further pressure medium is automatically introduced when a predetermined limit value of the pressure is exceeded.

This measure has the advantage that automatic monitoring of the seal is possible.

This is particularly important from an environmental point of view, especially in hydraulic steel construction. If piston-cylinder units are used on locks, dams, weirs and the like, they are regularly far below the water surface and therefore cannot be inspected. If the seals on these cylinders wear out. pressure medium can escape and contaminate the surrounding water. This is particularly critical with reservoirs that serve as drinking water reservoirs.

In contrast, with the described embodiment, it is possible to continuously monitor the tightness function and, if necessary, to restore the necessary tightness of the pressing device by “reloading” the expandable structure. As mentioned, this can be done automatically, e.g. via an electronic pressure switch.

In addition, other applications are of course also possible with conventional cylinders, such as those e.g. be used on machines, presses or the like. If the user recognizes there that pressure fluid is escaping, he can "readjust" the pressing device, similarly to a normal maintenance of the machine, and in turn ensure a correct function, whereby the predetermined coefficient of friction can be set.

In a preferred group of exemplary embodiments of the invention, the pressure medium is contained in an interior of an actuation unit and can be transferred into the interior of the expandable structure by means of a piston via the pointed cannula.

This measure has the advantage that the pressure medium is kept in the immediate vicinity of the seal, so that no separate connection has to be made. In a preferred development of this exemplary embodiment, the piston can be deflected manually, in particular by means of screws.

This measure has the advantage that the pressure medium can be supplied in a simple manner by means of a device which can be produced inexpensively. When actuated by means of screws, e.g. high pressure can be exerted manually by means of a piston adjustable by a spindle.

Alternatively, it is also possible to deflect the piston using external force.

This measure opens up the possibility of driving any control curves by remote control and / or adjusting a plurality of seals via a central control.

In particularly preferred embodiments of the invention, the piston can be adjusted automatically, preferably by means of a spring.

This measure has the advantage that a continuous refilling of pressure medium is ensured even in inaccessible places, even if it cannot be recognized from the outside that an adjustment is necessary due to the lack of accessibility of the seal.

It is further preferred if a stop for the travel path of the cannula is provided when the expandable structure is pierced by means of the cannula. This measure has the advantage that damage to the structure on the side opposite the puncture point is prevented, which could lead to leakage.

In another embodiment of the invention, the cannula is automatically retractable after being inserted into the expandable structure, preferably by means of a spring.

This measure has the advantage that the expandable structure can “self-heal” when the cannula is withdrawn and the punctured skin of the expandable structure closes behind the withdrawn cannula.

In a further series of exemplary embodiments, it is preferred to keep the further printing medium ready in a cartridge which is provided in the region of the expandable structure.

This measure has the essential advantage that the additional pressure medium does not have to be metered and filled in each case. Rather, the cartridges filled with the printing medium can be kept ready and used in the device during assembly or, if necessary, to replace an empty cartridge.

The cartridge can preferably be pierced by means of a first pointed end of the cannula, while a second pointed end of the cannula pierces the expandable structure. This measure has the advantage that the cartridge is connected directly to the expandable structure by a single movement of the cannula.

It is further preferred in these exemplary embodiments if a piston is arranged in the cartridge and the piston can be actuated from the outside for emptying.

This measure has the advantage that a reliable and complete emptying of the cartridge can be ensured.

In another group of embodiments, the print medium is supplied from an external unit.

This measure has the advantage that a large number of sealing devices can be supplied and controlled from a central unit. Furthermore, this variant of the invention is particularly suitable for applications in which correspondingly large amounts of pressure medium are required for large seals. These large quantities or volumes can be supplied more easily from a control center, especially since the control center, if it supplies several such seal arrangements, only has to keep the amount of pressure medium available which corresponds to the statistical probability of the seal failing.

In a preferred development of this variant, the pressure medium fed from a central unit simultaneously presses the pointed cannula through the expandable structure. This measure has the advantage that not only the pressure medium can be remotely controlled but also the engagement of the cannula can be controlled.

Furthermore, it is preferred in this group of exemplary embodiments if a mixing of liquid and gaseous pressure medium takes place during the external supply of pressure medium.

This measure has the advantage that e.g. a desired consistency of the pressure medium can be set by introducing air bubbles into the liquid pressure medium (gel) in the expandable structure.

The invention is preferably used in connection with ring seals on piston-cylinder arrangements. The arrangement can be installed "from the outside", i.e. in an inner wall of a cylinder for sealing against a piston or a piston rod running in the cylinder. Alternatively, an installation "from the inside" can also be selected, i.e. in an outer peripheral surface of a piston or a piston rod for sealing against a surrounding cylinder.

After all, depending on the structural conditions, different installation positions can preferably be specified. The external force for deflecting the cannula and / or an external pressure medium can thus be supplied in a direction lying in the plane of the ring seal, ie in the radial direction. This type of construction is particularly suitable for an arrangement “from the outside”. Alternatively, however, the external force and / or the pressure medium can also be located perpendicular to the plane of the ring seal Direction, ie in the axial direction, are supplied. This design is particularly suitable for an arrangement "from the inside".

In a further group of exemplary embodiments of the invention, a bearing point is addressed, i.e. an arrangement in which there is a bearing between an outer body and an inner body. The bearing can be, for example, a ball bearing or a plain bearing.

In order to ensure in this case as well that wear or settlement of the components of the bearing can be subsequently compensated, it is provided that at least one half of the bearing is designed to be expandable. This half of the bearing is preferably an outer ring of the bearing.

In a further development of this exemplary embodiment of the invention, the expandable bearing half is provided with an annular space and a pressure medium can be supplied to the annular space by means of a pressure medium line. The annular space is preferably arranged in a metallic outer ring and can be acted upon by a hydraulic pressure medium.

In these exemplary embodiments of the invention, the advantage is achieved that remote-controlled adjustment by pressurizing an expandable body is also possible. With regard to the manner in which the pressure medium is acted upon, the means used for this purpose and the controls used, with regard to the achievable advantages, reference can be made to the exemplary embodiments of the invention dealt with above in connection with a seal. Further advantages result from the description and the attached drawing.

It goes without saying that the features mentioned above and those yet to be explained below can be used not only in the combination indicated in each case, but also in other combinations or on their own without departing from the scope of the present invention.

Exemplary embodiments of the invention are shown in the drawing and are explained in more detail in the following description. Show it:

Fig. La shows an axial section through a first embodiment of a Blähring seal according to the invention, which is used between a cylinder and a piston rod;

Fig. Lb a section of Fig la, on an enlarged scale;

2 to 13

further embodiments of the invention in representations similar to Fig. La; Fig. 14 and 15

a further embodiment of an invention that can be used in the context of a storage location.

In Fig. La and lb, 10 denotes a piston-cylinder arrangement. This comprises a piston 11 (or a piston rod) and a cylinder 12 in which the piston 11 or the piston rod runs. An existing game is indicated in Fig. Lb with 13 (not to scale).

An annular seal 20 is used to seal the piston 11 or the piston rod to the cylinder 12. The annular seal 20 comprises a first sealing body 21 which is approximately H-shaped in axial section, preferably made of a first plastic. A second sealing body 22 of a different sealing material, preferably made of a second, harder plastic, as is known per se, is located in the first sealing body 21 on the running surface to the piston 11.

On the side of the seal 20 facing away from the second seal body 22, an expandable structure, in the exemplary embodiment shown, a tube 23 is embedded in the top of the first seal body 21. The hose 23 is also preferably made of a plastic, for example a silicone rubber. The tube 23 has an interior space 24 which is filled with a pressure medium, preferably with a pressure fluid, for example a gel. A channel 25 to the seal 20 runs in the radial direction in the cylinder 12. The channel 25 is open to the seal 20, ie it opens onto the surface of the hose 23 that is exposed there.

A pointed cannula 26 runs in the channel 25 and is designed in such a way that it can penetrate the surface of the tube 23, so that the cannula 26, i. whose longitudinal channel can connect to the interior 24 of the hose 23.

On the outside of the cylinder 12, an actuating unit, designated as a whole by 30, is provided. In the embodiment shown in Fig. 1, the actuating unit comprises

30 a screw head 31 which can be rotated on a body 32. The body 32 is screwed firmly into the cylinder 12 and is provided with a corresponding counter thread for the screw head 31 at its end facing away from the cylinder 12. The screw head 31 and the body 32 are hollow in the transition area. The screw head 31 is provided with a piston 33 which runs in an interior 34 of the screw head 31 or body 32. The interior 34 is also filled with a pressure medium, which is preferably the same pressure medium as that in the hose 23.

In the starting position (not shown in FIG. 1 a), the needle body 35 is pressed upwards by the spring 36 so far that the pointed cannula 26 is not yet in engagement with the tube 23.

However, if it is found that the seal 20 is worn and must therefore be readjusted, the screw head

31 of the actuating unit 30 by hand or by means of a stuff or servomechanically rotated by means of a remote control so that the piston 33 moves downward in FIG. The pressure medium present in the interior 34 presses the needle body 35 downward against the force of the spring 36 until the pointed cannula 26 pierces the tube 23, so that the interior 34 of the actuating unit 30 with the interior 24 of the tube 23 in Connection is coming. The needle body 35 runs against a stop 37 in the cylinder 12. This prevents the cannula 26 or needle from being inserted too deeply. Damage to the hose 23 on the side opposite from the insertion side is thus ruled out.

By further turning the screw head 31, pressure medium can now be “reloaded” into the interior 24 of the hose 23 until the seal 20 is tight again and takes on its sealing function completely and the prescribed contact pressure and coefficient of friction have been reached. The hose 23 serves as a pretensioning element. However, the pressure can also be reduced in a corresponding manner if necessary.

The "reloading" of the hose can not only be carried out when the seal is worn. Reloading is also advisable when the seal has "settled", i.e. if the required pretension has decreased due to aging shrinkage of the sealing materials used.

The screw head 31 can then even be turned back, if necessary, so that the cannula 26 is removed from the tube 23 again. The material of the hose 23 can namely be so "self-healing" that the pierced The surface of the hose 23 closes again automatically in the region of the channel 25 without a pressure loss occurring in the hose 23.

In the variant shown in Fig. 2, a less complicated arrangement is chosen. When the screw head 31a is turned, the pressure medium in the interior 34a is pressed downward by the piston 33a migrating out and flows through the needle or cannula 26a into the interior of the hose 23a. Since there is no starting position (spring 36) through which the cannula 26a is initially held in a position retracted from the seal 20a or the tube 23a, the tube 23a must already be in the variant according to FIG. 2 when the seal is being installed 20a can be pierced.

In the variant according to FIG. 3, the tube 23b of the seal 20b is also pierced during the assembly of the seal 20b. In this case, the adjustment is made if necessary, i.e. with progressive wear or repositioning of the seal 20b automatically by the piston 33b being provided with an adjusting spring 40. The adjusting spring 40 ensures a uniform after-flow of pressure medium through the cannula 26b into the hose 23b as soon as the pressure in the hose 23b decreases due to wear of the seal 20b.

4, there is no additional pressure medium within the "actuating unit" 30c. The adjustment of the seal 20c in the sense described is effected in this exemplary embodiment by supplying an external pressure medium, as indicated by an arrow 42 Arrow 42 stands for the connection to a central supply and control unit (not shown).

The externally supplied pressure medium flows through the cannula 26c into the hose 34c. The cannula 26c can already be inserted into the tube during installation. Alternatively, the externally supplied pressure medium can also be used to first pierce the tube 34c with the cannula 26c. For this purpose, the cannula 26c can be arranged axially rigid in a piston-like cannula holder 46, which is deflected by the inflowing external pressure medium.

The external pressure medium can, but need not, be the same pressure medium as in the hose 23c. It can be a gas or a liquid. A check valve indicated by 41 in FIG. 4 ensures that the supplied external pressure medium cannot flow out again, so that the pressure in the hose 23b is maintained.

In the event that a gas is used as the external pressure medium, it is also indicated in Fig. 4 with 43 that gas bubbles, e.g. Air bubbles, in a liquid pressure medium, e.g. a gel that can be introduced.

The arrangement acc. Fig. 4 is particularly suitable due to its external pressure medium supply and control for seals with large dimensions, in which relatively large volumes of pressure medium are required. Furthermore, this arrangement can preferably be used for those cases in which a plurality of such sealing arrangements are controlled via a central supply and control. In the exemplary embodiment according to FIG. 5, the adjustment takes place via a pneumatic or hydraulic connection 44, which is connected to a corresponding line 45. The line 45 in turn leads to a central control unit (not shown). The piston 33d is deflected by applying a pressure. The piston 33d in turn acts on the only schematically drawn cannula 26d. In this case, the hose 23d is also pierced by the hydraulic actuation, for example, and the adjustment can also be carried out by means of the hydraulics.

In contrast to the example according to Fig. 4 is here only the control shifted to a central office, while the pressure medium supply is ensured via local depots at the location of the seal.

In the exemplary embodiment according to FIG. 6, which is very similar to that according to FIG. 5, the piercing and the adjustment take place via a pressure medium line 45e, which is only indicated schematically, e.g. an air duct, i.e. pneumatic. In this case, too, both the piercing and the readjustment are effected by means of the hydraulic / pneumatic system via the piston 33e. A check valve 46 ensures that no pressure medium can flow back into line 45e.

7, the deflection of the cannula 26f or needle is effected via a thread 47. A set screw 48 runs in the thread 47 and is connected to the piston 33f. The adjusting screw 48 is actuated, for example, from the outside, for example by means of an Allen key, as indicated by a corresponding recess 49. In the exemplary embodiment according to FIG. 8, the arrangement is rotated through 90 ° in order to be able to access it in the axial direction from a flange 50 of the cylinder 12g. The actuation in turn takes place via a thread 51 or an adjusting screw 52, which acts on the piston 33g. An angled channel 53 leads from the interior 34g, which is acted upon by the piston 33g, to the cannula 26g, which in the example shown is permanently installed, ie, it pierces the hose 23g at the time of installation.

In the exemplary embodiment according to FIG. 9, an external positive displacement pump 55 with a spindle 56 is used. A pressure medium is fed via a pressure line 57 from a pressure chamber 58 to the displacement pump 55 to the actuating unit 30h. In this way, the hose can be pierced and, if necessary, reloaded, with several cylinders from a central lubrication system, i.e. a central supply and control unit can be operated.

10, the kinematically reversed situation is shown. There the seal 20i is located on the piston III instead of on the cylinder 12e. However, similar to the previous exemplary embodiment according to FIG. 9, an end-side actuation option is again provided. A positive displacement pump (not shown) is also provided here, which can be connected to the arrangement from the outside.

A connector 60 of the positive displacement pump is designed to be movable in the axial direction. It can be inserted in the direction of an arrow 62 into a corresponding opening 61 in an end face of the cylinder and then inserted with a threaded pin 63 into a threaded bore 64 in an end face 65 of the piston III. be screwed. The axially movable connector 60 can follow the axial movement of the piston III. After the pressurization has ended, the threaded bore 64 is closed by means of a screw plug (not shown).

The seal 20i is supplied with pressure medium via the angled channel 53i. As already described several times, the seal 20i can either only be acted upon by an external pressure medium for transferring a pressure medium reservoir already present in the seal (see exemplary embodiment according to FIG. 5) or the pressure medium required for reloading the hose is also supplied externally (cf. embodiment according to FIG. 4).

The exemplary embodiment according to FIG. 11 is a first mechanical variant of the exemplary embodiment according to FIG. 10. The piston 33k running in a bore is actuated via a plunger 67, which is adjustable from the outside, as indicated by an arrow 69. For this, e.g. an adjustment rod of an actuator serve which engages in a threaded bore 68 on the rear of the plunger 67. The piston 33k is secured against falling out of the bore (not shown). In this exemplary embodiment, too, the bore is closed in a pressure-tight manner after the pressurization has ended, for example also by means of a screw plug.

The exemplary embodiment according to FIG. 12, on the other hand, shows a second mechanical variant of the exemplary embodiment according to FIG. 10. The plunger 331 is actuated by the plunger 671 in such a way that the plunger 671 ends in a head 71 which is provided with the threaded connection 681. The head 71 is with one Provided external thread 72 which runs in an extension 73 on the end face 651 of the piston 111. In this case too, the plunger 671 or the piston 331 can be actuated from the outside, as indicated by the arrow 691.

The embodiment according to FIG. 13 is again of a different type. Similar to the exemplary embodiment according to FIGS. 1a and 1b, the body 32m of the actuating unit 30m is screwed into the cylinder 12m and a screw head 31m is screwed onto the body 32m at the top.

In the screw head 31m, preferably in its axis, there is a bolt 76 which is axially rigidly connected to the screw head 32m at a fastening point 75. The bolt 76 runs into a threaded tip 77 at its end facing away from the fastening point 75. The bolt 76 extends into an axial through bore 78 of the body 32m.

A cartridge 80 for receiving the pressure medium is located in the through bore 78 of the body 32m. The cartridge 80 has at its upper end a collar 81 which is designed for the positive reception of the threaded tip 77. At the bottom, the cartridge 80 is closed off by a base 84. In the cartridge 80, below the collar 81, there is a piston 82 which is axially displaceable in the interior 83 of the cartridge 80.

A piston 85 also runs below the cartridge 80 in the through bore 78. The cannula 26m is fixed axially rigidly in the piston 85. The cannula 26m is provided with a tip both at its upper end 87 and at its lower end 88. The path of the piston 85 in the through hole 78 is downward delimited by a package 89 of a plurality of plates arranged one above the other, which rests on the stop 37m of the cylinder 12m and serves as a sealing element between the cannula 87 and the cylinder 12m.

The mode of operation of the arrangement according to FIG. 13 is as follows:

First, when the actuating unit 30m is installed and the screw head 31m is unscrewed, the cartridge 80 is inserted into the through bore 78 from above. The piston 85 with the cannula 26m at both ends 87, 88 is already located in the through hole 78 on the packet 89. The cartridge 84 is thereby loosely placed with its bottom 84 on the upper pointed end 87 of the cannula 26m.

Now the screw head 31m is screwed on. With a suitable marking, the screw head 31m is screwed on as far as shown in Fig. 13, i.e. so far that the cannula 26m with its two pointed ends 87 and 88 is just loosely clamped between the bottom 84 of the cartridge 80 and the tube 23m. The threaded tip 77 preferably already engages the collar 81 in a form-fitting manner.

If necessary, the screw head 31m is now rotated further, so that the threaded tip 77 now engages in the collar 81 at the latest, and cannot be lost, e.g. by a self-tapping thread, a bayonet-like connection or the like.

The bolt 76 now pushes the piston 82 down. Since the pressure medium in the interior 83 of the cartridge 80 cannot escape, the cartridge 80 is moved in the through hole 78 towards ten moved. As a result, the bottom 84 of the cartridge 80 is pierced by the upper tip end 87 of the cannula 26m, while the lower tip end 88 pierces the tube 23m. This clears the way for the pressure medium from the interior 83 of the cartridge 80 into the interior of the hose 23m.

By turning back the screw head 31m, the now empty cartridge 80 is pulled out upwards, since the threaded tip 77 engages captively in the collar 81.

It goes without saying that the cartridge arrangement according to FIG. 13 can also be used in all the other exemplary embodiments shown.

14 and 15 show two further exemplary embodiments for a further area of application of the invention.

In Fig. 14, 90 generally designates a bearing point. The bearing point 90 is located in the area between an outer body 91, for example a housing, and an inner body 92, for example a shaft mounted in the housing. A ball bearing 93 is arranged between the bodies 91, 92. The ball bearing 93 has an outer ring 94 and an inner ring 95 in a manner known per se.

According to the invention, an annular space 96 is provided in the outer ring 94. A pressure medium line 97 leads to this annular space 96.

The outer ring 94 is preferably made of metal. It is dimensioned so that by applying a high pressure in the annulus 96 an expansion of the outer ring 94 occurs (or an expansion of the inner ring 95 if an annular space is arranged therein). Since a very high pressure must be generated in the annular space 96 when using a metallic outer ring 94, a hydraulic medium is preferably supplied via the pressure medium line 97.

Expansion of the outer ring 94 can compensate for wear in the area of the bearing 90.

For the supply of the pressure, the setting of the pressure, the monitoring of the bearing 90, etc., the devices and procedures can be used which have been described above with reference to the exemplary embodiments in FIGS. 1 to 13.

Correspondingly, FIG. 15 shows a bearing point 100 with an outer body 101 and an inner body 102. In this case, a sliding bearing 103 is located between the bodies 101 and 102. The sliding bearing 103 has an outer ring 104 and an inner ring 105 provided in the outer ring 104. The annular space 106 is connected to a pressure medium line 107.

With regard to the mode of operation and the details, the exemplary embodiment according to FIG. 15 corresponds to that of FIG. 14.

It is understood that the bearing points 90, 100 are only to be understood as examples. The bearings can be used with axial and radial bearings. The exemplary embodiments described above can be used for numerous applications. However, applications in the area of large cylinders are particularly preferred. Large cylinders are used in heavy machinery and presses.

A particularly preferred application example is the use of such large cylinders in hydraulic steel construction. For example, in dams or weirs, in locks, ship lifts and the like. Such piston-cylinder units are used which are arranged under water to actuate corresponding gates, locks and the like.

If the seals between the piston / piston rod and cylinder wear out in such applications, hydraulic fluid (oil) escapes to the outside over time. With large cylinders in hydraulic steel construction, such wear and such an escape of hydraulic fluid usually go unnoticed initially because the piston-cylinder units are usually located below the water surface. When used in large dams, these units can e.g. 20 to 30 m below the top of the dam, so they are no longer recognizable from the water surface.

Since pressure medium reservoirs with a capacity of typically 100,000 liters are used in such large cylinders, it can well happen that a considerable part of this large amount of oil escapes without being noticed. This is particularly critical in the case of dams because dams often serve as drinking water reservoirs. Large amounts of pollution could occur without being recognized. It is therefore preferred in the context of the present invention to use a pressure switch which, for example, continuously monitors the pressure in the interior 24 of the hose 23. As the seal 20 wears out over time, the pressure in the interior 24 slowly decreases. The pressure value can be transferred, for example, via a corresponding measuring line to a manometer, which is located in the control position of the dam. If the temperature falls below a certain limit, the supervisor can be instructed or the hose 23 can be "reloaded" in its interior 24 by moving the cannula 26 forward in the channel 25 in order in this way to provide further pressure fluid to inject into the interior 24 of the tube 23. A wide variety of aids can be used for the adjustment required, for example mechanical, hydraulic, pneumatic, electromagnetic or the like.

In this way it can thus be ensured that on the one hand the life of the seal 20 is significantly extended, on the other hand can be achieved by appropriate monitoring and reasonable setting of the limit value that the sealing effect of the seal 20 never drops below a certain value, so that the leakage of Hydraulic fluid (oil) in the surrounding water (drinking water) is safely avoided.

In this way, the present invention also has a very significant environmental significance and significance.

Claims

claims 1. Device for the radial pressing of a sealing body (21, 22) in order to seal a first machine part against a second machine part, in particular for sealing a cylinder (12) against a piston rod (11) or a piston, wherein an annular seal ( 20) is provided with the sealing body (21, 22), which lies tightly against the second machine part and in which there is an expandable, in particular hose-like structure (23) between the sealing body (21, 22) and the first machine part, which has an interior space (24), in which a pressure medium is located, the volume of the pressure medium being able to be compensated for to compensate for wear or a repositioning of the sealing body (21, 22), characterized in that means are provided to by means of the expandable structure (23) to pierce a cannula (26) and introduce further pressure medium into the interior (24). 2. Pressure device according to claim 1, characterized in that a pressure in the interior (24) monitors and that the further pressure medium is automatically introduced when a predetermined limit value of the pressure is exceeded. 3. Pressure device according to claim 1 or 2, characterized in that the structure (23) is first installed in the undamaged state in the ring seal (20) and operated there and that only when there is predetermined wear or repositioning of the material of the sealing body (21, 22nd ) the structure (23) is pierced. 4. Pressure device according to claim 1 or 2, characterized in that the structure (23) already during installation of the ring seal (20) and a predetermined coefficient of friction of the sealing body (21, 22) is reached and that with a predetermined wear or repositioning of the material of the sealing body (21, 22) the further pressure medium is introduced. 5. pressing device according to one or more of claims 1 to 4, characterized in that the pressure medium in an interior (34) of an actuating unit (30) and by means of a piston (33) via the pointed cannula (26) in the interior (24 ) of the structure (23) can be transferred. 6. pressing device according to claim 5, characterized in that the piston (33) can be deflected manually. 7. pressing device according to claim 6, characterized in that the piston can be deflected by means of screws. 8. pressing device according to claim 5, characterized in that the piston (33d, 33e) can be deflected by external force. 9. pressing device according to claim 5, characterized in that the piston (33b) is automatically adjustable. 10. pressing device according to claim 9, characterized in that the piston (33b) by means of a spring (40) is automatically adjustable. 11. pressing device according to one or more of claims 1 to 10, characterized in that when piercing the structure (23) by means of the cannula (26) a stop (37) is provided for the travel of the cannula (26). 12. Pressure device according to one or more of claims 1 to 11, characterized in that the cannula (26) is automatically retractable after being inserted into the structure (23). 13. pressing device according to claim 12, characterized in that the cannula (26) by means of a spring (36) is automatically retractable. 14. Pressure device according to one or more of claims 1 to 13, characterized in that a cartridge (80) is provided in the region of the structure (23m) for receiving the printing medium. 15. Pressure device according to claim 14, characterized in that the cartridge (80) can be pierced by means of a first pointed end (87) of the cannula (26m), while a second pointed end (88) of the cannula (26m) the structure (23m) punctures. 16. Pressure device according to claim 15, characterized in that a piston (82) is arranged in the cartridge (80) and that the piston can be actuated from the outside for emptying the cartridge. 17. Pressure device according to one or more of claims 1 to 16, characterized in that the pressure medium can be supplied by an external unit. 18. Pressure device according to claim 17, characterized in that the pressure medium supplied from an external unit simultaneously presses the pointed cannula (26c) through the structure (34c). 19. Pressure device according to claim 17 or 18, characterized in that a mixing of liquid and gaseous pressure medium takes place during the external supply of pressure medium. 20. Pressure device according to one or more of claims 1 to 19, characterized in that the ring seal (20) from the outside, in particular in a cylinder (12) for sealing against a piston (11) running in the cylinder (12) or a piston rod is. 21. Pressure device according to one or more of claims 1 to 19, characterized in that the ring seal (20i) from the inside, in particular on a piston (lli) or a piston rod for sealing against a piston (lli) surrounding cylinder (12i) is. 22. Pressure device according to one or more of claims 1 to 21, characterized in that the external force for deflecting the cannula (26) and / or an externally supplied pressure medium is supplied in a direction lying in the plane of the ring seal (20). 23. Pressure device according to one or more of claims 1 to 21, characterized in that the external force for deflecting the cannula (26g) and / or an externally supplied pressure medium is supplied in a direction perpendicular to the plane of the ring seal (20g). 24. Use of a pressure device according to one of claims 1 to 23 in hydraulic steel construction, in press and / or mechanical engineering. 25. Bearing point with a bearing (93; 103) arranged between an outer body (91; 101) and an inner body (92; 102), characterized in that at least one bearing half is designed to be expandable. 26. Bearing point according to claim 25, characterized in that the bearing half is an outer ring (94; 104) of the bearing (93; 103). 27. Bearing point according to claim 25 or 26, characterized in that the bearing is a ball bearing (93). 28. Bearing point according to claim 25 or 26, characterized in that the bearing is a plain bearing (103). 29. Bearing point according to one or more of claims 25 to 28, characterized in that the expandable bearing half is provided with an annular space (96; 106) and that the annular space (96; 106) by means of a pressure medium line (97; 107) a pressure medium can be supplied is. 30. Bearing according to claim 29, characterized in that the annular space (96; 106) is arranged in a metallic outer ring (94; 104) and can be acted upon with a hydraulic pressure medium.