Clamping cylinder device

Description

[0001] The invention relates to a clamping cylinder device having the features in the preamble of claim 1. Furthermore, the invention relates to a collet chuck, in particular for securing two flange halves to one another.

[0002] Clamping cylinder devices featuring a longitudinally movable piston-rod unit for generating an actuating force are state of the art. Such cylinder devices are frequently used as holding cylinders or actuating cylinders, for example, in power plants. Particularly when used as holding cylinders, it must be ensured that the generated clamping force does not decrease even over a long period of time. This requirement must be met, especially in offshore applications of clamping cylinder devices. Clamping cylinder devices are used to hold flange halves together with a predetermined force, for example, on underwater housings or pipelines or the like. In such systems, several clamping cylinder devices are often arranged around the circumference of flanges.

[0003] For example, DE 10 2011 009 276 A1 has already proposed a device for transmitting a hydraulic working pressure in a pressure fluid for the pressure actuation of hydraulic devices in deep-sea installations, wherein a cylinder arrangement has a first pressure chamber for the pressure fluid, a piston arrangement which is movable to change the volume of this pressure chamber and at least one second pressure chamber which can be subjected to the ambient pressure of the deep sea for a movement of the piston arrangement which generates the working pressure in the first pressure chamber. In this known solution, the working pressure in the cylinder arrangement is not generated or transmitted by means of the seawater acting directly on the piston arrangement, but a pressure accumulator is connected upstream of the cylinder arrangement, from which pressure accumulator an actuating fluid which is under the deep-sea pressure can be supplied to the cylinder arrangement in order to generate the required working pressure.

[0004] JP H02-192829 A describes a clamping cylinder device with the features in the preamble of claim 1, having a housing and a piston-rod unit arranged therein so as to be at least partially longitudinally displaceable, and having a compensating element in the form of a bellows body having bellows folds, which is variable in length and is in media-conducting connection with a compressible medium accommodated in a media space in the housing, wherein the bellows body is clamped in the housing between a fixing point located thereon and a movable guide plate which separates a second media space with incompressible medium from the media space with the compressible medium.

[0005] Further clamping cylinder devices are disclosed in DE 103 10 930 A1, JP 2001-248760 A, and US 2 533 413 A.

[0006] Based on this prior art, the invention aims to provide a clamping cylinder device by means of which the reliable generation of a permanent actuating force is possible over long operating periods.

[0007] According to the invention, this object is achieved by a clamping cylinder device which has the features of patent claim 1 in its entirety.

[0008] According to the characterizing part of claim 1, it is provided that the piston-rod unit within the housing separates the second media chamber with the incompressible medium from a further, third media chamber with a likewise incompressible medium in a media-tight manner, that the housing is a circular-cylindrical housing which is closed by a base to form a pot, and that a closure head is provided as the housing closure at the opposite end of the housing.

[0009] Because the housing contains a media chamber containing a compressible medium, for example a working gas such as N 2 , which is connected to a length-adjustable bellows body, a compressed gas volume is available as an energy store. Since this chamber is closed off and thus hermetically sealed by a length-adjustable bellows body, preferably in the form of a metal bellows, operational reliability is guaranteed over long periods of time. The tensioning cylinder device according to the invention is therefore particularly suitable for underwater use. Since the length-adjustable bellows body can serve as a transmission element for the actuating force generated by the energy store to the piston-rod unit, the tensioning cylinder device according to the invention is also characterized by a simple, compact, and functionally reliable design.

[0010] The bellows body is clamped in the housing between a retaining point located thereon and a movable guide plate, which separates a second media chamber containing the incompressible medium from the media chamber containing the compressible medium. The guide plate can be welded to the adjacent last bellows fold as the bellows body's end closure plate. However, a commercially available metal bellows sealed at least on one side can also be used.

[0011] Advantageously, the bellows body can be dimensioned such that the outer side of its bellows folds is guided along the inner side of the cylindrical housing, which increases the buckling stability.

[0012] Within the housing, the piston-rod unit separates the second media chamber containing the incompressible medium from a third media chamber containing a similarly incompressible medium. This creates a compact, manageable unit.

[0013] In this arrangement, the prevailing pressure in the first media chamber, containing the compressible medium, acts via the bellows body's guide plate, and the pressure in the second media chamber, containing the incompressible medium, acts on the piston-rod unit. The incompressible medium, which forms the intermediate transmitter for the actuating forces acting between the guide plate and the piston-rod unit in the second media chamber, can be a highly viscous oil, whose viscosity forms a type of damping cushion between the guide plate and the adjacent end face of the piston-rod unit.

[0014] The further, third media chamber can be provided with a control connection which, when subjected to fluid pressure that is greater than the pressure of the compressible medium, allows the piston-rod unit to be retracted in the direction of the guide plate.

[0015] The pressure supply via the control port can be designed such that, when the piston-rod unit is fully extended, a piston face rests against a residual volume of incompressible medium in the third media chamber. In the fully extended state, a damping fluid cushion is therefore also located between this face of the piston and the facing wall of the housing that defines the third media chamber, helping to prevent direct metallic surface contact.

[0016] In advantageous embodiments, the rod of the piston-rod unit has an outwardly closable through-opening which opens into the second media space and which serves to receive the incompressible medium, which, as mentioned above, is preferably a highly viscous oil.

[0017] The closure head can have the control connection. The rod of the piston-rod unit can extend outward through a central bore in the closure head, with sealing elements located within the bore forming the seal for the third media chamber located on the rod side of the piston.

[0018] The fixing point for the bellows body can advantageously be formed from a fixing ring which engages stationary in a recess in the inner wall of the housing.

[0019] The subject matter of the invention according to claim 11 is also a collet, in particular for securing two flange halves to one another with a predeterminable clamping force which is also maintained over a long period of use, with two clamping jaws which in particular delimit a clamping space for receiving the two flange halves, wherein one clamping jaw can be moved towards and away from the other clamping jaw and wherein the collet is characterized in that at least one clamping jaw can be moved by means of a clamping cylinder device according to one of claims 1 to 10.

[0020] The invention is explained in detail below with reference to the drawings. They show: Fig. 1 shows a longitudinal section of an embodiment of the clamping cylinder device according to the invention, approximately 6.5 times smaller than a practical embodiment, showing the clamping state; Fig. 2 shows a longitudinal section of an embodiment of the clamping cylinder device according to the invention, Fig. 1Fig. 3 shows a longitudinal section of the exemplary embodiment, rotated by 90°, showing the release state; and Fig. 3 shows a highly schematic longitudinal section of a collet chuck actuatable by means of the clamping cylinder device according to the invention.

[0021] The illustrated embodiment of the clamping cylinder device has a circular cylindrical housing 2, which is designed to form a pot on the Fig. 1 and 2 The left-hand end is closed by a base 4. A screwed-in closure head 6 is provided as the housing closure at the opposite end of the housing 2. As a holder for installation in a respective system, the housing 2 is welded in the area of ​​the base 4 to a holding body 8, which has projecting fastening parts 10 on two opposite sides.

[0022] The part of the housing 2 adjacent to the base 4 serves as the first media chamber 12, which can be filled with a working gas, such as N 2, at high pressure, for example 250 to 300 bar, via a filling connection 14 arranged on the base 4 coaxially to the longitudinal axis 16 of the housing. The end of the media chamber 12 opposite the base 4 is formed by a bellows body 18, which is designed as a metallic bellows and is guided with the outer side of its bellows folds so that it can be adjusted lengthwise on the inner wall of the housing 2. The bellows body 18 is fixed to a fixing point on the housing 2 with its open end facing the base 4. In the example shown, this is formed by a retaining ring 22 to which the last bellows fold of the bellows body 18 is welded or simply applied and which, in the manner of a snap ring, sits in a recessed recess 24 in the inner wall of the housing 2.At the other end, the bellows body 18 is closed by a guide plate 26 which is welded to the adjacent last bellows fold or is simply applied, which is longitudinally movable in the housing 2 and is guided on the housing inner wall by a guide 28.

[0023] As the Fig. 1 and 2 show, the fixing ring 22 is fixed to the inner wall of the housing 2 in a position in which the length of the first media chamber 12 containing the compressed gas is substantially greater than the remaining length of the housing 2 remaining in the housing 2 from the fixing point on the fixing ring 22 to the outer end of the closure head 6. Fig. 1 and 2In the example shown, the locking ring 22 is arranged at a position where the distance from the base 4 is approximately 1.6 times the distance from the outer end of the closure head 6. In the housing section between the guide plate 26 and the closure head 6, a piston-rod unit is arranged, the piston 30 of which is longitudinally movable in the housing 2 and sealed by means of a piston seal 32. From the side of the piston 30 facing the closure head 6, the rod 34 of the piston-rod unit extends outwards through a through-bore 36 formed in the closure head 6 coaxially to the cylinder axis 16, with sealing elements 38 forming the seal between the rod 34 and the closure head 6.

[0024] The rod 34 has a channel 40 coaxial with the axis 16, which extends from the flat piston side of the piston 30 facing the guide plate 26 to the outer free end of the rod 34. Via the channel 40, a highly viscous oil can be filled as an incompressible medium into a second media chamber 42, which is located between the flat piston side of the piston 30 and the guide plate 26. The annular space surrounding the rod side of the piston 30 and extending to the facing end of the closure head 6 forms a third media chamber 44 for an incompressible medium. The oil supplied to this third media chamber 44 via a control connection 46 ( Fig. 2 ) of the locking head 6 and an incompressible medium, such as hydraulic oil, which can be supplied via a control channel 48, forms the control medium for a release process of the clamping cylinder device.

[0025] The Fig. 1shows the clamped state of the device, in which there is no effective control pressure in the third media chamber 44 that would counteract the gas pressure prevailing in the first media chamber 12. The pressure of the first media chamber 12, which serves as an energy store, has therefore extended the bellows body 18, with the guide plate 26 applying a displacement force to the piston 30, so that the rod side of the piston 30 has moved against the closure head 6 and the rod 34 has been extended into the clamped position. The viscous oil in the gap-like second media chamber 42 between the guide plate 26 and the piston 30 acts as a cushion that dampens the metallic contact. A residual volume of hydraulic oil serving as the control medium that remains in the third media chamber 44 despite the lack of control pressure also acts in the third media chamber 44 as a cushion that prevents direct mechanical contact between the rear side of the piston 30 and the closure head 6.

[0026] The Fig. 2shows the release state with control pressure supplied via control port 46. With the smaller rod-side pressure-effective piston area in the media chamber 44, the control pressure is supplied at a pressure level that is much higher than the working gas pressure prevailing in the first media chamber 12, for example, with a release oil pressure of 700 bar, with a gas pressure of 250 to 300 bar prevailing in the energy storage device (media chamber 12).

[0027] The high-viscosity oil introduced into the media chamber 42 via channel 40, which establishes the force coupling between the bellows guide plate 26 and the base of the piston 30, can preferably be provided with a correspondingly larger fill quantity in order to compensate for possible losses via the respective sealing system. Furthermore, the pressure at the pressure connection 46 can be continuously monitored by a pressure sensor (not shown). If a pressure increase is detected in the media chamber 44 when the device is in the clamped state, i.e., when there is no control pressure in the media chamber 44, a leak in the piston 30 can be determined, so that scheduled maintenance with replacement of sealing elements can be carried out. With state-of-the-art clamping devices that operate with spring force, such monitoring is not possible.

[0028] The Fig. 3shows a simplified schematic representation of a collet 52 for securing schematically drawn flange halves 54 and 56 between two clamping jaws 58 and 60, which define a clamping space 62 for receiving the flange halves 54, 56. The piston rod 34 of the clamping cylinder device according to the invention forms a movable part of the clamping jaw 60 in the form of a pressure piece 64, which when actuated by means of the Fig. 1 and 2 shown example of the clamping cylinder device is movable with a clamping stroke of 100 mm. The flange halves 54, 56 shown are held together in the fixed state by means of the clamping jaws 58 and 60 of the collets 52 exclusively by the gas pressure in the first media chamber 12. Since the metal bellows 18 is designed to be media-tight and, as shown, according to the associated Fig. 1The guide plate 26, which is sealed by the seal 28, is pressed against the high-pressure oil volume of the media chamber 42, which also forms a type of seal, thus preventing gas losses and achieving a long-lasting, force-locking connection.

Claims

1. Clamping cylinder device, with a housing (2) and a piston-rod unit (30, 34) arranged so as to be at least partially longitudinally displaceable therein and with a compensating element in the form of a bellows body (18) having bellows folds, which bellows body can be varied in length and is in media-conducting communication with a compressible medium accommodated in a media chamber (12) in the housing (2), wherein the bellows body (18) is clamped in the housing (2) between a fixing point (22) located thereon and a movable guide plate (26), which separates a second media chamber (42) with incompressible medium from the media chamber (12) with the compressible medium, characterised in that within the housing (2), the piston-rod unit (30, 34) separates the second media chamber (42) with the incompressible medium from a further, third media chamber (44) with a likewise incompressible medium in a media-tight manner, in that the housing (2) is a circular cylindrical housing (2) which is closed by a base (4) to form a pot, and in that a closure head (6) is provided at the opposite end of the housing (2) as the housing closure.

2. Clamping cylinder device according to claim 1, characterised in that the outer side of the bellows folds of the bellows body (18) is guided along the inner side of the cylindrical housing (2).

3. Clamping cylinder device according to claim 1 or 2, characterised in that the respectively prevailing pressure in the media chamber (12) with the compressible medium is transmitted via the guide plate (26) of the bellows body (18) and via the second media chamber (42) with the incompressible medium to the piston-rod unit (30, 34).

4. Clamping cylinder device according to one of the preceding claims, characterised in that the further, third media chamber (44) is provided with a control connection (46) which, when acted upon by fluid pressure that is greater than the pressure of the compressible medium, allows the piston-rod unit (30, 34) to be retracted in the direction of the guide plate (26),5. Clamping cylinder device according to one of the preceding claims, characterised in that, in the fully extended state of the piston-rod unit (30, 34), an end-face piston surface bears against a residual volume of incompressible medium in the third media chamber (44).

6. Clamping cylinder device according to one of the preceding claims, characterised in that the rod (34) of the piston-rod unit (30, 34) has a through-hole (40), which can be closed to the outside, which opens into the second media chamber (42) and which is used to receive the incompressible medium.

7. Clamping cylinder device according to claim 4, or according to claim 5 or 6, if dependent on claim 4, characterised in that the closure head (6) comprises the control connection (46).

8. Clamping cylinder device according to one of the preceding claims, characterised in that the fixing point for the bellows body (18) is formed from a retaining ring (22) which engages stationarily in a recess (24) in the inner wall of the housing (2).

9. Collet, in particular for fixing two flange halves to each other with a predefinable clamping force which is also maintained over a longer period of use, having two clamping jaws (58, 60, 64), which in particular define a clamping space (62) for receiving the two flange halves (54, 56), wherein the one clamping jaw (60, 64) can be moved towards and away from the other clamping jaw (58), characterised in that at least the one clamping jaw (60, 64) is movable by means of a clamping cylinder device (2, 34) according to one of the preceding claims.