Cylinder-piston unit

Abstract

The invention relates to a cylinder-piston unit (1, 2) comprising: at least one cylinder tube (23, 24); a base (25); and a cover (26) through which, for each cylinder tube, at least one piston rod (27, 28) extends, the piston rod being connected to at least one piston which can be moved within the cylinder tube (23, 24) along the longitudinal axis thereof and which can be acted upon by a working medium, connections (9, 10, 11) for said working medium being provided in at least the base (25) and / or the cover (26) and / or the cylinder tube (23, 24). A direct threaded connection (29, 30, 31, 32) is formed between at least the base (25) or the cover (26) and the cylinder tube (23, 24). An arrangement (40, 41, 42, 43, 44, 45) for fixation in the circumferential direction is provided for each threaded connection.

Description

[0001] CYLINDER-PISTON UNIT

[0002] The invention relates to a cylinder-piston unit, with at least one cylinder tube, a base and a cover, through which at least one piston rod protrudes per cylinder tube, which is connected to at least one piston movable in the cylinder tube along its longitudinal axis, which piston can be acted upon by a working medium, for which connections are provided in at least the base and / or the cover and / or the cylinder tube.

[0003] Such units are used in many areas of technology for the reliably controllable and precisely definable movement of components, for example in the exact alignment of tools that are used alternately in two different positions, e.g. in a lower tool that is used on a bending machine for both folding and pressing.

[0004] The manufacturing effort, as well as the additional weight and associated costs, should be reduced as much as possible. A significant disadvantage of conventional designs is the excessive thickness of the cylinder tubes required to accommodate the mounting screws for the base and lid of the unit. This thickness is significantly greater than the maximum pressure in the cylinder tube would require, resulting in unnecessarily high material requirements, weight, and costs.

[0005] CN 217002481 U discloses an easy-to-assemble oil cylinder consisting of a cylinder body, a mounting ring, and a movable rod. The cylinder body has an internal thread at the end of the cylinder cover, into which the cylinder cover can be screwed with an external thread. The outer edge area of ​​the cylinder body is covered by an outer jacket on the cylinder cover, with an annular circumferential groove formed between this jacket and the external thread of the cylinder cover. The movable rod is guided through the cylinder cover. For assembly, the threaded connection between the cylinder body and the cylinder cover is created by turning, enabling quick disassembly and assembly, improving assembly and machining of the device, and improving assembly efficiency.

[0006] The object of the present invention was to overcome the disadvantages of the prior art and to provide a device which, with a small overall size, in particular with regard to the wall thickness of the cylinder tube, offers high mechanical stability and security against the loosening of the connections between the individual components and nevertheless promotes a simple and rapid production of the unit.

[0007] This object is achieved by a device according to the claims.

[0008] The device according to the invention is characterized in that a direct threaded connection is formed between at least the base or the cover and the cylinder tube, and that an arrangement for fixing in the circumferential direction is provided for each threaded connection.

[0009] This allows for wall thicknesses precisely matched to the maximum pressure in the cylinder tube, without unnecessarily increasing the weight and complexity of the cylinder-piston unit. However, the wall thickness does not need to be increased just to accommodate the base or cover.

[0010] It is preferably provided that the cylinder tube is provided with an external thread at at least one end, and that the base and / or the cover is provided with a corresponding internal thread.

[0011] This design allows easy machining of the cylinder tube and facilitates the connection to the base and / or the cover.

[0012] An advantageous embodiment of the invention is characterized in that at least one connection point is arranged on the outside of the cylinder tube, and that a connecting means extends from the base and / or cover with internal thread, preferably running parallel to the longitudinal axis of the cylinder tube, which can be detachably connected to the connection point.

[0013] This fastener can create a preload in the threaded connection. This prevents unwanted loosening of the threaded connection and ensures the trouble-free operation of the unit under all circumstances.

[0014] A further embodiment of the invention provides that two cylinder tubes are connected to a common base and / or common cover, and that threaded connections are formed between the common base and / or cover and the cylinder tubes, and that an arrangement for fixing in the circumferential direction is provided for each threaded connection.

[0015] This also makes it possible to realize the advantage for such tandem units that wall thicknesses can be used that are precisely matched to the maximum pressure in the cylinder tubes, without unnecessarily increasing the weight and complexity of the cylinder-piston unit.

[0016] Here, too, an embodiment is preferred in which the fixing arrangement comprises a ring provided with an internal thread and screwed onto the external thread of the cylinder tube, with at least one bore, preferably parallel to the longitudinal axis of the cylinder tube.

[0017] This design allows easy machining of the cylinder tube and facilitates the connection to the base and / or the cover.

[0018] Such a unit is advantageously characterized in that the arrangement for fixing comprises at least one longitudinal element, preferably running parallel to the longitudinal axis of the cylinder tube and extending between the base and / or cover and the ring, for connecting the base and / or cover to the screwed-on ring.

[0019] This prevents unwanted loosening of the threaded connection and ensures trouble-free operation of the unit in all cases.

[0020] An advantageous embodiment provides that the longitudinal element is a screw guided through the ring, which forms a threaded connection with a threaded hole in the cover and / or the base.

[0021] This provides a simple and quick way to secure the unit's threaded connections, as well as a quick way to loosen and tighten them if necessary.

[0022] Preferably, several longitudinal elements distributed around the circumference of the cylinder tube and correspondingly several bores are provided in the ring screwed onto the cylinder tube and the cover and / or the base. This allows the mechanical stress on the individual fixing arrangements in the circumferential direction to be reduced, and excessive stress on individual fixing arrangements can be avoided.

[0023] An alternative embodiment of the invention is characterized in that the fixing arrangement comprises at least one longitudinal element, preferably running parallel to the longitudinal axis of the cylinder tube and extending between the base and / or cover and the ring, for support on the base and / or cover and / or an intermediate ring.

[0024] By means of this longitudinal element, a force can be generated which pushes the ring and base and / or the lid and / or the intermediate ring, which in turn supports itself on the base and / or the lid, away from each other and clamps the threaded connections in such a way that they are fixed against rotation.

[0025] It is preferably provided that the longitudinal element is a screw guided through the ring and held in a threaded bore of the ring.

[0026] This provides a simple and quick way to secure the unit's threaded connections, as well as a quick way to loosen and tighten them if necessary.

[0027] Furthermore, an advantageous embodiment of this embodiment provides that several longitudinal elements distributed around the circumference of the cylinder tube and correspondingly several threaded holes are present in the ring screwed onto the cylinder tube.

[0028] This also makes it possible to reduce the mechanical load on the individual fixing arrangements in the circumferential direction and to avoid excessive loads on individual fixing arrangements.

[0029] A particularly advantageous embodiment of a tandem unit is characterized by two cylinder tubes with a common base and a common cover, each connected by threaded connections. External threads with identical pitch and opposite rotational directions are machined at the opposite ends of the cylinder tubes, and corresponding internal threads are machined in the base and cover. This embodiment offers the advantage that by rotating the cylinder tube, the threaded connections at both ends are simultaneously tightened equally.

[0030] A further embodiment is preferred in which the threads at the opposite ends of the cylinder tubes are mirror-symmetrical with respect to each plane containing the longitudinal axis of the cylinder tube.

[0031] This design offers the advantage that by rotating the cylinder tube, the threaded connections at both ends are tightened in the same way and with the same force.

[0032] Overall, the inventive design of threaded connections between the cylinder tubes and the base and / or the cover allows for a simpler production, with lower material expenditure, particularly with regard to the wall thickness of the cylinder tubes, and thus also a more cost-effective production, with savings of over 15%.

[0033] For a better understanding of the invention, it is explained in more detail using the following figures.

[0034] They show in a highly simplified, schematic representation:

[0035] Fig. 1 is a perspective view of a conventional cylinder-piston unit in tandem design;

[0036] Fig. 2 is a longitudinal section through the unit of Fig. 1;

[0037] Fig. 3 is a perspective view of an embodiment of a cylinder-piston unit according to the invention in tandem design;

[0038] Fig. 4 is a longitudinal section through the unit according to the invention of Fig. 3;

[0039] Fig. 5 is an enlarged view of the cover end of the unit of Fig. 3 in

[0040] longitudinal section;

[0041] Fig. 6 is an enlarged longitudinal section view of the bottom end of the unit of Fig. 3, and Fig. 7 is an enlarged perspective view of the bottom end of the unit of Fig. 3 with the bottom shown transparent;

[0042] Fig. 8 is a perspective view of a further alternative embodiment of a cylinder-piston unit according to the invention in tandem design;

[0043] Fig. 9 is a longitudinal section through the unit according to the invention of Fig. 8;

[0044] Fig. 10 is an enlarged view of the bottom end of one side of the unit of the

[0045] Fig. 8 in longitudinal section.

[0046] By way of introduction, it should be noted that in the variously described embodiments, identical parts are provided with identical reference symbols or identical component designations, whereby the disclosures contained in the entire description can be transferred mutatis mutandis to identical parts with identical reference symbols or identical component designations. Furthermore, the positional information chosen in the description, such as top, bottom, side, etc., refers to the directly described and illustrated figure, and if the position changes, these positional information must be transferred mutatis mutandis to the new position. Finally, for the sake of clarity, it should be pointed out that, to improve understanding of the structure, some elements have been shown not to scale and / or enlarged and / or reduced.

[0047] Fig. 1 shows two conventional piston-cylinder units 1, 2 in tandem design, in which two similar and identically designed piston-cylinder units 1, 2 are connected in parallel and here even connected by a common base 3 and a common cover 4. A piston rod 7, 8 from each cylinder tube 5, 6 is passed through the common cover 4 and can be coupled with its free end to the load to be moved. The base 3 here has a connection element 9 common to both cylinder tubes 5, 6 for the supply and / or discharge of the working medium. On the cover side, another possibility for supplying or discharging the working medium is shown, namely separate connection elements 10, 11 on each cylinder tube 5, 6.

[0048] As shown in Fig. 2 using the example of the conventional attachment of the cover 4 to the cylinder tubes 5, 6, screws 12 running parallel to the longitudinal axis of the cylinder tubes 5, 6 are screwed into corresponding receptacles in the cylinder tubes 5, 6, which therefore must have a great thickness that far exceeds the thickness that would be necessary due to the pressure conditions. The base 3 is also connected to the cylinder tubes 5, 6 in the same way, and this method of connecting the cylinder tube, cover and base is also common in individual piston-cylinder units 1, 2. It should also be mentioned here that the at least one piston that is movable in the cylinder tube 5, 6 along its longitudinal axis and can be acted upon by the working medium is not shown in the drawings for the sake of simplicity.

[0049] The inventive design of at least one piston-cylinder unit 21, 22 is explained below with reference to Figures 3 to 7, again using a tandem arrangement of two parallel piston-cylinder units 21, 22 as an example. The inventive connection of cylinder tube 23, 24 with base 25 and / or cover 26 can be used for individual piston-cylinder units, for units in any combination arrangements, and for any type of piston-cylinder unit with regard to mode of operation, working medium, and connection types. At least one piston rod 27, 28 is guided through the cover 26 for each cylinder tube 23, 24.

[0050] As can be seen specifically from Fig. 4, a threaded connection 29, 30, 31, 32 is provided for the axial connection between the cylinder tubes 23, 24 and the base 25 and / or the cover 26. For this purpose, the embodiment shown in Fig. 5 as an example for the cover 26 is preferably provided, in which an external thread 33, 34 is machined on at least one end of the cylinder tube 23, 24, which is screwed into an internal thread 35, 36 of the cover 26, so as to form a direct threaded connection between the cylinder tubes 23, 24 and the cover 26. To prevent accidental loosening of this threaded connection, at least one arrangement 39 to 45 for fixing in the circumferential direction is provided for each threaded connection 29, 30, 31, 32, which arrangement is explained in more detail below.By connecting the components of the cylinder-piston unit 21, 22 in this way, the cylinder tube 23, 24 can be kept very thin and precisely adjusted to the maximum pressure in the cylinder tube.

[0051] Fig. 6 shows a similar threaded connection as an example for the base 25, in which an external thread 37 is also machined at the base end of the cylinder tube 23, which is shown alone here. A complementary internal thread 38 is present in the base 25, into which the cylinder tube 23 is screwed with its external thread 37. The enlarged view of Fig. 6 also illustrates, with reference to the threaded connection 31, a preferred embodiment for its fixation in the circumferential direction, which can preferably be provided for all threaded connections between cylinder tubes and the base and / or cover.

[0052] For this purpose, a ring 40 provided with an internal thread 39 is screwed onto the external thread 37 of the cylinder tube 23. Similar rings 41, 42, 43 are preferably provided for the remaining threaded connections, as can be seen in Figs. 4 and 5. These rings 40, 41, 42, 43 are preferably screwed onto the end of the respective external thread of the cylinder tube 23, 24. At least one connection point is arranged on or in each of these rings 40, 41, 42, 43 in order to preferably detachably connect a connecting means to the base 25 and / or the cover 26. These connecting means are preferably designed as screws 44 which extend parallel to the longitudinal axis of the cylinder tube 23, 24 and rigidly connect the base 25 or the cover 26 orthogonally to the direction of rotation of the threaded connection with the rings 40, 41, 42, 43 in order to thereby prevent a relative rotation of the base 25 or the cover 26.Cover 26 and ring 40, 41, 42, 43 and thus secure the threaded connections against unintentional loosening.

[0053] Preferably, as can also be seen in Figures 3 to 7, the screws 44 are first guided through holes in the rings 40, 41, 42, 43, which may optionally be designed as threaded holes. The ends of the screws 44 opposite the screw head engage in threaded holes 45 in the base 25 or the cover 26. However, embodiments are also conceivable in which these relationships are reversed, ie the screws 44 extend from the base 25 and / or the cover 26 and are anchored in threaded holes in the rings 40, 41, 42, 43.

[0054] The screws 44 engage the upper and lower sides of the base 25 and / or cover 26 or rings 40, 41, 42, 43. The heights or thicknesses of the base 25 and / or cover 26 or rings 40, 41, 42, 43 are selected such that a gap remains between these components, so that when the screws 44 are tightened, the thread flanks of the threaded connections 29, 30, 31, 32 are pressed together, thereby prestressing the threaded connections and preventing relative rotation of the base 25 and / or cover 26 or rings 40, 41, 42, 43. Preferably, several connecting means, for example several screws 44, are provided per threaded connection, evenly distributed along the circumference of the respective cylinder tube 23, 24. The number of screws 44 can be selected according to the desired preload of the respective threaded connection.Accordingly, several bores or threaded bores 45 are also machined in the rings 40, 41, 42, 43 and / or in the base 25 and / or cover 26 in order to be able to establish the connection between these components in many relative circumferential positions.

[0055] Fig. 8 is a perspective view of another alternative embodiment of a cylinder-piston unit according to the invention in tandem design, in which threaded connections 29, 30, 31, 32 (see Fig. 9) again establish the axial connection between the cylinder tubes 23, 24 and the base 46 and / or the cover 47. For this purpose, the base

[0056] 46 and / or the cover 47 again have an internal thread worked out, into which an external thread at the end of the cylinder tubes 23, 24 can be screwed.

[0057] The arrangement for preventing accidental loosening of these threaded connections, however, is constructed somewhat differently than previously described. The screws 44, as preferred examples of a longitudinal element preferably running parallel to the longitudinal axis of the cylinder tube 23, 24 and extending between the base 46 and / or the cover 47 and the ring 41, do not engage in threaded holes in the base or the cover, but rather are supported directly on the base 46 and / or the cover 47, or are preferably supported on an intermediate ring 48, which in turn is supported on the base 46 and / or the cover

[0058] 47 rests or is supported on it. Fig. 10 shows these structural conditions for the connection of the base 46 with one of the cylinder tubes 23 on an enlarged scale.

[0059] By means of this longitudinal element, preferably by means of several screws 44 distributed around the circumference of the cylinder tubes 23, 24 and inserted into threaded bores in the rings 41, a force can be generated that urges the ring 41 and the base 46 and / or the cover 47 and / or the intermediate ring 48 away from each other. This clamps the threaded connections between the ring 41 and the cylinder tube 23, 24 on the one hand, and between the cylinder tubes 23, 24 and the base 46 and / or the cover 47 in opposite directions, preventing relative rotation due to the significantly increased friction of the threads and thus clamping each of the threaded connections in such a way that they are fixed against any movement.For the tandem arrangement of two piston-cylinder units 21, 22 shown as an example in Figures 3 to 10, according to an advantageous embodiment, the two cylinder tubes 23, 24 are connected to a common base 25 or 46 and a common cover 26 or 47 by means of threaded connections 29, 30, 31, 32, wherein external threads 33, 34, 37 with identical pitch and opposite direction of rotation are provided at the opposite ends of the cylinder tubes 23, 24 and the corresponding internal threads 35, 36, 38 are provided in the base 25, 46 and in the cover 26, 47.For this embodiment, the threads at the opposite ends of the cylinder tubes 23, 24 are furthermore preferably mirror-symmetrical with respect to each plane containing the longitudinal axis of the cylinder tube, in order to simultaneously tighten or loosen the threaded connections at both ends in the same way and with the same force by rotating the cylinder tube.

[0060] Advantageously, at least one static sealing arrangement is present in each of the threaded connections 29, 30, 31, 32, preferably in the form of at least one O-ring with at least one anti-extrusion ring.

[0061] The sealing packings, preferably comprising at least one wiper ring, primary and secondary seals, and guide rings, are preferably offset from the lower flanges to avoid having to increase the thickness of the cylinder tubes 23, 24 to create sealing grooves. This allows the working stroke to be maximized for a given overall length, or the minimum overall length can be achieved for a given working stroke.

[0062] The exemplary embodiments show possible embodiments. It should be noted at this point that the invention is not limited to the specifically illustrated embodiments, but rather various combinations of the individual embodiments are also possible. This variation possibility, based on the teaching of technical action by means of the present invention, lies within the skill of the person skilled in this technical field.

[0063] Piston-cylinder unit 40 Ring Piston-cylinder unit 41 Ring Bottom 42 Ring

[0064] Lid 43 Ring

[0065] Cylinder barrel 44 Screw cylinder barrel 45 Threaded hole piston rod 46 Base piston rod 47 Cover

[0066] Connecting element base 48 intermediate ring Connecting element cover Connecting element cover screw

[0067] Piston-cylinder unit Piston-cylinder unit Cylinder barrel

[0068] Cylinder tube bottom

[0069] Lid

[0070] Piston rod Piston rod

[0071] Threaded connection Threaded connection Threaded connection Threaded connection External thread External thread Internal thread Internal thread

[0072] external thread external thread

[0073] internal thread

Claims

Patent claims 1. Cylinder-piston unit (1, 2), each with at least one cylinder tube (23, 24), a base (25) and a cover (26), through which cover at least one piston rod (27, 28) protrudes per cylinder tube, which is connected to at least one piston movable in the cylinder tube (23, 24) along its longitudinal axis, which piston can be acted upon by a working medium, for which connections (9, 10, 11) are provided in at least the base (25) and / or the cover (26) and / or the cylinder tube (23, 24), characterized in that a direct threaded connection (29, 30, 31, 32) is formed between at least the base (25) or the cover (26) and the cylinder tube (23, 24), and in that an arrangement (40, 41, 42, 43, 44, 45) for fixing in the circumferential direction is provided for each threaded connection.

2. Unit according to claim 1, characterized in that the cylinder tube (23, 24) is provided at at least one end with an external thread (33, 34, 37), and that the base (25) and / or the cover (26) is provided with a corresponding internal thread (35, 36, 39).

3. Unit according to claim 1 or 2, characterized in that at least one connection point is arranged on the outside of the cylinder tube (23, 24), and that between the base (25) and / or cover (26) with internal thread there extends a connecting means (44) which preferably runs parallel to the longitudinal axis of the cylinder tube (23, 24) and which can be detachably connected to the connection point.

4. Unit according to one of claims 1 to 3, characterized in that two cylinder tubes (23, 24) are connected to a common base (25) and / or common cover (26), and threaded connections (29, 30, 31, 32) are formed between the common base (25) and / or cover (26) and the cylinder tubes (23, 24), and that for each threaded connection an arrangement (40, 41, 42, 43, 44, 45) is provided for fixing in the circumferential direction.

5. Unit according to one of claims 1 to 4, characterized in that the arrangement for fixing comprises a screw provided with an internal thread and screwed onto the external thread (33, 34, 37) of the cylinder tube (23, 24) screwed ring (40, 41, 42, 43) with at least one bore, preferably oriented parallel to the longitudinal axis of the cylinder tube.

6. Unit according to claim 5, characterized in that the arrangement for fixing comprises at least one longitudinal element (44) which preferably runs parallel to the longitudinal axis of the cylinder tube (23, 24) and extends between the base (25) and / or cover (26) and the ring (40, 41, 42, 43) for connecting the base and / or cover and the ring.

7. Unit according to claim 6, characterized in that the longitudinal element is a screw (44) guided through the ring (40, 41, 42, 43) which forms a threaded connection with a threaded bore (45) in the cover (26) and / or the base (25).

8. Unit according to claim 6 or 7, characterized in that there are several longitudinal elements (44) distributed around the circumference of the cylinder tube (23, 24) and a corresponding number of bores in the ring (40, 41, 42, 43) screwed onto the cylinder tube and the cover (26) and / or the base (25).

9. Unit according to claim 5, characterized in that the arrangement for fixing comprises at least one longitudinal element (44) which preferably runs parallel to the longitudinal axis of the cylinder tube (23, 24) and extends between the base (46) and / or the cover (47) and the ring (40, 41, 42, 43) for support on the base and / or the cover and / or an intermediate ring (48).

10. Unit according to claim 9, characterized in that the longitudinal element is a screw (44) guided through the ring (40, 41, 42, 43) and held in a threaded bore of the ring (40, 41, 43, 43).

11. Unit according to claim 9 or 10, characterized in that there are several longitudinal elements (44) distributed around the circumference of the cylinder tube (23, 24) and a corresponding number of threaded bores in the ring (40, 41, 42, 43) screwed onto the cylinder tube.

12. Unit according to one of claims 4 to 11, characterized in that two cylinder tubes (23, 24) with a common base (25, 46) and a common cover (26, 47) are connected by respective threaded connections (29, 30, 31, 32), wherein external threads (33, 34, 37) with identical pitch and opposite direction of rotation are provided at the opposite ends of the cylinder tubes and the corresponding internal threads (35, 36, 39) are provided in the base and in the cover.

13. Unit according to claim 12, characterized in that the threads (33, 34, 37) at the opposite ends of the cylinder tubes (23, 24) are mirror-symmetrical with respect to each plane containing the longitudinal axis of the cylinder tube.

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