EP1744062B1 - Actuator with dampening at the end of stroke - Google Patents

Abstract

The cylinder has a piston (4) supported in a longitudinal displaceable manner between two end positions. A damping device for damping the movement of the piston has a retaining opening (15) and a casing (19), in which the opening is provided at an end part. The opening and the casing are inserted into one another in the piston movement direction, where the casing is movable to an end position during the convergence of the piston at its end positions. The casing is movable to another end position and again returns to its initial position, when the piston moves away from its end position.

Description

In the form of a tube or a Strangofilteils, two cylinder end-closing end portions, a longitudinally displaceably mounted in the cylinder space between two end positions of the piston and a device for damping the movement of the cylinder Piston when approaching at least one of its end positions.

In particular, pressure-actuated working cylinders are often designed with a Endlagendämfpung to ensure a bumpless working of the cylinder. An example of such a fluid-actuated cylinder with cushioning is in the U.S. Patent 6,758,127 described. In this working cylinder, an axially projecting tubular, cylindrical damping pin is provided on both sides of the piston, in the end piece facing it the cylinder body is associated with a receiving opening, in which the damping pin is immersed in the approach of the piston to its end position. The receiving opening is connected to a device for throttled discharge of trapped in the damping chamber pressure medium. This device may for example have a throttle valve. The path length, the piston covers when approaching an end position from the position in which the damping pin begins to penetrate straight into the receiving opening and the damping chamber closes up to the position in which the piston has reached its actual end position and, for example, with its end face rests on the end face of the associated end part, is referred to as damping stroke. The length of this damping stroke is determined by the axial length of the damping pin and thus the depth of the receiving opening, which in turn is limited by the axial dimensions, ie the thickness of the end portion. Since the installation length of a working cylinder is often specified, for example by standards, for a given piston stroke and the damping stroke can not be made arbitrarily large.

On the other hand, especially in the movement of large masses a longer damping distance, ie a longer damping stroke makes sense, because thereby the kinetic energy of the moving masses can be better degraded, which leads to lower reaction forces on the substructure and usually also a better adjustability, especially with additional elements results. At one of the DE 297 06 364 U1 known endlagegedämpften working cylinder is a main ring piston of the working cylinder a ring magnet-bearing control piston upstream, which is connected via conical springs with the main piston and slidably slides on the piston rod. The spool also serves as a shut-off valve and valve for outflow, wherein forms a damping reservoir in the system of the control piston at the respective end portion of the working cylinder, from the fluid via a throttled Abströmbohrung can flow out. While this cylinder has a longer damping travel or stroke compared to the prior art, the cone spring requires additional installation space, except that the use of spring elements is problematic in many applications because of their limited life.

Basically the same applies to a known working cylinder from the U.S. Patent 3,999,463 (and in principle similar to the JP 11132203A and DE 3818833A1 ) in which the means for damping the movement of the piston when approaching at least one of its end positions comprises two cooperating damping elements, one of which is provided on one end portion of the working cylinder and the other on the piston on its end portion facing side. The two damping elements close at the approach of the piston to its end position a damping chamber, which is connected to a device for throttled discharge of trapped in the damping chamber pressure medium. For this purpose, the two damping elements in the direction of the piston movement are axially inserted into one another by one of the two damping elements has a receiving opening formed in the end portion and the other has a sealingly inserted into the receiving opening damping pin. The damping pin has a sleeve which is mounted axially displaceably limited axially on a rod-shaped bearing part projecting axially from the piston and which is directly part of the piston rod. Of the two when closing the piston to its end position inserted into each other designed damping elements which is limited to the piston between two axially spaced end positions with respect to the piston longitudinally displaceably mounted and loaded with a spring which biases it into one of its end positions.

The object of the invention is therefore a working cylinder to provide cushioning, the damping device is characterized by a simple, reliable construction and with limited installation length of the entire working cylinder has a large damping stroke.

To solve this problem, the working cylinder according to the invention has the features of claim 1.

In the new cylinder both damping elements are provided with cooperating inhibiting means under the action of the longitudinally displaceable damping element is adjustable in a movement of the piston from its end position to an end position which is further away from the piston or the end portion as a first end position, the Damping element normally occupies. The displaceability of the one damping element with respect to the piston or the end part results in an additional damping stroke by a telescopic action of the telescoping action of the piston as it approaches its end position. The inhibitor ensures that when the path Piston from its end position, the longitudinally displaceable damping element returns to its original position, without the need for additional actuators, such as spring elements or the like. This also no additional installation space is required. The simple design also allows the use of near-serial parts for large damping strokes, ie long damping paths.

Further advantageous features and embodiments of the working cylinder according to the invention are the subject of dependent claims.

The working cylinder can be both a single-acting and double-acting working cylinder with a piston rod brought out through at least one of its end parts, but the idea according to the invention can equally be applied to rodless cylinders. The working cylinders are usually pressure medium actuated, for example. Pneumatic cylinder, but a corresponding device for cushioning can also be provided in working cylinders or linear drives, which have a different form of operation, for example. Over cables and the like.

Fig. 1

Einen Arbeitszylinder gemäß der Erfindung im Längsschnitt in einer Seitenansicht, unter Veranschaulichung einer mittleren Hubstellung des Kolbens,

Fig. 2

eine Einzelheit "Y" des Arbeitszylinders nach Figur 1 in einer vergrößerten Ausschnittsdarstellung,

Fig. 3

eine Einzelheit "Z" des Arbeitszylinders nach Figur 1 in einer vergrößerten Ausschnittsdarstellung,

Fig. 4

den Arbeitszylinder nach Figur 1 in einer entsprechenden Schnittdarstellung, unter Veranschaulichung einer Hubstellung des Kolbens, bei der die beiden Dämpfungselemente der Endlagendämpfungseinrichtung gerade miteinander in Eingriff kommen,

Fig. 5

den Arbeitszylinder nach Figur 1 in einer entsprechenden Schnittdarstellung, unter Veranschaulichung einer Hubstellung, bei der die beiden Dämpfungselemente der Endlagendämpfungseinrichtung ganz ineinander eingeschoben sind,

Fig. 6

den Arbeitszylinder nach Figur 1 in einer entsprechenden Schnittdarstellung, unter Veranschaulichung einer Hubstellung, bei der der Kolben seine Endlage erreicht hat,

Fig. 7

den Arbeitszylinder nach Figur 1 in einer entsprechenden Schnittdarstellung, unter Veranschaulichung einer Hubstellung des Kolbens, bei der sich der Kolben aus seiner Endlage wieder teilweise wegbewegt hat und

Fig. 8

einen Arbeitszylinder gemäß der Erfindung in der Ausführung als kolbenstangenloser Zylinder, im Längsschnitt in einer Seitenansicht, unter Veranschaulichung einer Hubstellung des Kolbens, bei der der Kolben sich einer Endlage annähert und die beiden Dämpfungselemente bereits miteinander in Eingriff gekommen sind.

In the drawings, embodiments of the subject matter of the invention are shown. Show it:

Fig. 1

A working cylinder according to the invention in longitudinal section in a side view, illustrating an average stroke position of the piston,

Fig. 2

a detail "Y" of the working cylinder after FIG. 1 in an enlarged detail,

Fig. 3

a detail "Z" of the working cylinder after FIG. 1 in an enlarged detail,

Fig. 4

the working cylinder after FIG. 1 in a corresponding sectional view, illustrating a stroke position of the piston, in which the two damping elements of Endlagendämpfungseinrichtung straight with each other,

Fig. 5

the working cylinder after FIG. 1 in a corresponding sectional view, illustrating a stroke position in which the two damping elements of the end position damping device are completely inserted into one another,

Fig. 6

the working cylinder after FIG. 1 in a corresponding sectional view, illustrating a stroke position in which the piston has reached its end position,

Fig. 7

the working cylinder after FIG. 1 in a corresponding sectional view, illustrating a stroke position of the piston, in which the piston has moved away from its end position again partially and

Fig. 8

a working cylinder according to the invention in the embodiment as a rodless cylinder, in Longitudinal section in a side view, illustrating a stroke position of the piston, wherein the piston approaches an end position and the two damping elements have already come into engagement with each other.

The FIGS. 1 to 7 illustrate a working cylinder in the form of a pneumatic cylinder having a cylinder body in the form of a cylinder tube 1 and two sealed with the cylinder tube 1 end portions 2, 3. The cylinder tube 1 encloses a cylinder space in which a piston 4 is guided longitudinally displaceable, which is sealed against the inner wall of the cylinder tube 1 via piston ring seals 5. The piston 4 divides the cylinder space into two cylinder or pressure chambers 6, 7, which are separated by the piston 4.

With the piston 4, a coaxial cylindrical piston rod 8 is fixedly connected, which is sealed by the end part 2 is guided by. A piston rod seal is illustrated at 9. The cylinder chamber 6 passing through the piston rod 8 is extended on the opposite side of the piston. On its extension 10 a coaxial cylindrical sleeve 11 is placed, which projects into the cylinder chamber 7 and is fixed by a 12 indicated, bolted to the piston rod extension 10 screw on the piston 4.

In the two end portions 2, 3 each opening into a threaded bore 13 connecting channel 14 is formed, which via a corresponding screwed connection fitting with a compressed air source not shown or a vent, in each case via corresponding, also not shown valves, can be connected and opens on its other side in each case in a cylindrical, cup-shaped receiving opening 15, which opens on the piston 4 side facing the respective end portion 2 and 3 to the cylinder chamber 6 and 7 out. The coaxial to the piston rod receiving opening 15 is closed in both end portions 2, 3 on the side facing away from the piston 4, which is achieved at the end part 2 by the piston rod seal 9, while the receiving opening 15 in the other end part 3 by a molded-bottom part 16th is completed. Each of the two receiving openings 15 includes an inserted into an annular groove 18 in the vicinity of its mouth, around running elastic sealing element in the form of an O-ring 20th

The axial depth of the two receiving openings 15 is usually the same and dimensioned so that there is a maximum depth 21 without lengthening the installation length of the working cylinder.

The receiving opening 15 in each of the two end portions 2, 3 each forms a damping element of a device for cushioning the piston 4. It cooperates for this purpose with a second damping element, which is provided on the piston 4 and each having a telescopic damping pin which at the approach of the piston at its respective end position in the respective receiving opening 15 is sealingly inserted to limit a damping chamber, the pressure medium includes, which causes a throttling of the piston movement in the throttled outflow from the receiving opening a pneumatic damping.

The cooperating with the receiving opening 15 second damping element has a cylindrical sleeve 19 which is mounted on the end part 2 facing the side of the piston 4 on the piston rod 8 and on the other end part 3 facing the piston side on the cylindrical sleeve 11 each axially limited longitudinally displaceable. The sleeve 19 is chamfered on its side facing the respective end part 2, 3 at 22 outside and at its opposite end with an annular flange 23 which carries a respective end portion 2, 3 facing stop surface 24. The annular flange 23 of each of the two sleeves 19 is assigned in each case an annular groove 25 in the piston end face facing it, which can receive the annular flange 24 completely, as will be explained in detail yet.

As in particular the detail "Z" in FIG. 3 can be seen, each sleeve 19 is formed in the region of its inner wall with an annular shoulder 26 which cooperates with a corresponding annular shoulder 27 near the free end of the tube 11 on one side of the piston and an annular shoulder 28 on the piston rod 8 on the other side of the piston. The annular shoulders 27, 28 are spaced so far from the respective adjacent piston face and tuned to the length of the sleeve 19, that in the in FIG. 1 illustrated first piston remote end position in which the annular shoulders 26, 27 and 26, 28 abut each other, the two sleeves 19 are with its annular flange 23 at the same axial distance from the adjacent piston face and that in a second piston near end position of the flange 24 each completely in the annular groove 25 is received, as shown in FIG FIG. 6 for the end part 3 associated sleeve 19 is shown.

In the in FIG. 1 shown first end position, the two sleeves 19 are releasably locked. The associated latching device has an in an annular groove 29 and 30 of the piston rod 8 and the sleeve 11 inserted latching element in the form of an O-ring 31 which cooperates with a locking recess 32 on the inner wall of the sleeve 19 elastically yielding. In the illustrated first end position, the end portion 3 adjacent sleeve 19 protrudes axially over a large part of its length over the sleeve 11, while the other sleeve 19 rests on a larger diameter portion of the piston rod 8 over most of its length. Instead of locking can alternatively occur a frictional locking of the sleeves.

At the two sleeves 19 is also, for example. Subsequently to the chamfer 22, an all-round annular bead 32 is formed, which can cooperate with the respective O-ring 20 in the end part 2 and 3 and together with this inhibiting means for each of the respective End portion directed away axial movement of the sleeve 19 in the manner described below.

The two receiving openings 15 in the end parts 2, 3 are each provided with a device for throttled discharge of pressure medium enclosed in the damping space enclosed by the piston 4, the cylinder space or 7 and the end part 2 and 3, respectively. In the described embodiment, this device includes a throttle valve 33, which in the detail "Y" of FIG. 2 is illustrated in its details. The throttle valve 33 is inserted into a corresponding bore 34 of the respective end part 2 or 3, which via a coaxial channel 35 with the receiving opening 15 and a laterally outgoing channel 36th is in communication with the cylinder chamber 6 and 7, respectively.

The throttle valve 33 has a valve body 37 which is pressed by a valve spring 38 elastically against a valve seat 39, wherein the valve spring 39 is axially supported against a screwed into the bore 34 plug 40. The valve body 37 is formed in the manner of a differential piston. If the same medium pressure prevails in the two channels 35, 36, then the valve spring 38 can keep the valve body 37 closed on the valve seat 39 and thus the throttle valve ( Fig. 2 ). If the pressure in the damping chamber, and thus in the channel 35, increases by a preset value, the valve body 37 is lifted off the seat 39 accordingly. In the valve body 37, a throttle channel 40 of small cross-section is formed, through which air can flow out of the damping chamber into the adjacent pressureless cylinder chamber 6 or 7 when the valve is closed. The throttle channel 40 acts as a bypass channel.

• Bei der in Fig. 1 dargestellten mittleren Hubstellung des Kolbens 4 sind die beiden jeweils als längsverschiebbare, Dämpfungselement wirkenden Hülsen 19 in ihrer kolbenfernen Endstellung dargestellt, in der sie durch die beiden als Rastelemente wirkenden O-Ringe 31 verrastet sind. Die Ringschultern 26, 27 bzw. 26, 28 liegen aneinander an und definieren die erste kolbenferne Endstellung der Hülsen 19 bezüglich des Kolbens 4.
• Bei der in Fig. 4 veranschaulichten Hubstellung hat sich der Kolben 4 durch entsprechende Druckluftbeaufschlagung der Zylinderkammer 6 und Entlüftung der Zylinderkammer 7 gegenüber Fig. 1 soweit nach rechts bewegt, dass die Kolbenstange 8 fast ganz in den Arbeitszylinder eingefahren ist und die rechte Hülse 19 gerade mit dem ein Hemmmittel bildenden O-Ring 20 der Aufnahmeöffnung 15 des Endteils 3 in Eingriff kommt. Diese anfängliche Eingriffnahme wird durch die Anfasung 22 der Hülse 19 begünstigt. Die Hülse 19 und die durch die Schraube 12 verschlossene, über den O-Ring 31 gegen sie abgedichtete Büchse 11 schließen über den O-Ring 20 die Aufnahmeöffnung 15 ab und lassen einen Dämpfungsraum für den Kolben 4 entstehen. Gleichzeitig wird das freie Abströmen von Druckmedium aus der Zylinderkammer 7 über den Anschlusskanal 14 unterbunden. Druckmedium kann nurmehr über die Dämpfungskanäle 36, 40, 35 und das einstellbare Dämpfungsdrosselventil 33 aus der Zylinderkammer 7 abströmen.

The end position damping of the described working cylinder acts as follows:

• At the in Fig. 1 shown middle stroke position of the piston 4, the two are each shown as longitudinally displaceable, damping element acting sleeves 19 in their piston remote end position in which they are locked by the two acting as locking elements O-rings 31. The annular shoulders 26, 27 and 26, 28 abut each other and define the first piston-distal end position of the sleeves 19 with respect to the piston 4th
• At the in Fig. 4 illustrated stroke position, the piston 4 by appropriate Druckluftbeaufschlagung the cylinder chamber 6 and venting of the cylinder chamber 7 opposite Fig. 1 so far moved to the right that the piston rod 8 is almost completely retracted into the working cylinder and the right sleeve 19 just with the inhibiting means forming O-ring 20 of the receiving opening 15 of the end portion 3 engages. This initial engagement is favored by the chamfer 22 of the sleeve 19. The sleeve 19 and sealed by the screw 12, sealed via the O-ring 31 against it bushing 11 close over the O-ring 20 from the receiving opening 15 and leave a damping chamber for the piston 4 arise. At the same time the free outflow of pressure medium from the cylinder chamber 7 is suppressed via the connection channel 14. Pressure medium can only flow out of the cylinder chamber 7 via the damping channels 36, 40, 35 and the adjustable damping throttle valve 33.

If the piston 4, the piston rod 8 and a mass associated therewith continue to move in the direction of the end part 3 at a certain speed, a pressure increase in the cylinder chamber 7 which counteracts the movement, i.e. due to the restricted outflow of the pressure medium from the cylinder chamber 7, takes place. there is a damping of the movement of the piston 4 when approaching its end position.

In the course of the approach to its final position of the piston reaches 4 in Fig. 5 illustrated stroke position in which the longitudinally displaceable damping element in the form of the sleeve 19 is fully retracted into the receiving opening 15 and thus completely immersed in the end part 3. The stop surface 24 of the annular flange 23 strikes the associated end face of the end part 3, so that the sleeve 19 is locked in a form-fitting manner. At continued, after right directed movement of the piston 4, therefore, the locking action of acting as a locking element O-ring 31 is overcome, so that the piston 4, finally, the in Fig. 6 can reach shown end position, in which the annular flange 23 of the sleeve 19 is fully received in the annular groove 25 of the piston and the piston rests with its end face on the end face of the end part 3.

In this end position of the piston 4, the sleeve 19 is pushed over practically its entire length on the sleeve 11 and the screw 12, which protrudes axially slightly beyond the sleeve 19, as is apparent from Fig. 6 can be seen.

• Der Weg des Kolbens 4 von der Hubstellung aus, in der der Dämpfungsraum in der Zylinderkammer 7 gerade ausgebildet wird bis zu der Endlage in Fig. 6, wird als der Dämpfungshub 41 bezeichnet. Wäre, wie dies im Prinzip dem Stand der Technik entspricht, nur ein einheitlicher Dämpfungszapfen mit dem Kolben 4 verbunden, so ergäbe sich als Dämpfungshub nur der in Fig. 4 mit 42 bezeichnete (kleine) Weg, der im Wesentlichen durch die von der Anschlagfläche 24 aus gerechnete axiale Länge der Hülse 19 bestimmt ist. Da die Hülse 19 auf der Büchse 11 längsverschieblich gelagert ist, ergibt sich eine Teleskopwirkung, durch die der Dämpfungshub 41 im Vergleich zu dem erwähnten Dämpfungshub 42 auf fast das Doppelte vergrößert wird. Ohne Teleskopierung wäre bei gleicher axialer Länge des Arbeitszylinders nur ein Dämpfungshub 42 möglich. Wie bereits Eingangs erwähnt, ist insbesondere bei großen Massen eine längere Dämpfungsstrecke sinnvoll, weil sie u.a. zu einem besseren stoßfreien Abbau der kinetischen Energie beiträgt.

From a comparison of FIGS. 4 and 6 the length of the damping stroke can be read off:

• The way of the piston 4 from the stroke position, in which the damping chamber is formed in the cylinder chamber 7 straight up to the end position in Fig. 6 , is referred to as the damping stroke 41. If, as in principle corresponds to the prior art, only a single damping pin connected to the piston 4, so would be the damping stroke only in Fig. 4 42 (small) path, which is determined essentially by the calculated from the stop surface 24 from axial length of the sleeve 19. Since the sleeve 19 is mounted longitudinally displaceably on the sleeve 11, there is a telescopic effect, by which the damping stroke 41 is increased in comparison to the mentioned damping stroke 42 to almost twice. Without telescoping only one damping stroke 42 would be possible with the same axial length of the working cylinder. As already mentioned at the beginning, a longer damping distance makes sense, especially for large masses, because, among other things, it leads to a better bumpless one Reducing the kinetic energy contributes.

If the piston rod 8, starting from the end position to Fig. 6 , extends to the left again extends, the sleeve 19 is first pulled out of the receiving opening 15, because it is frictionally coupled via the O-ring 31 with the sleeve 11 and thus with the piston 4. In the course of this extension movement, however, the bead 32 runs against the O-ring 20 forming an inhibiting means, which prevents the sleeve 19, which has already been pulled out predominantly from the receiving opening 15, from completely leaving the receiving opening 15 (FIG. Fig. 7 ). In the further extension movement of the piston 4, therefore, the sleeve 11 is pulled out of the detained sleeve 15 until the annular shoulders 26, 27 abut each other and thus, with continued extension movement, the latching formed by the O-ring 20 and the bead 32 is overcome. This ensures that the sleeve 19 forming the displaceable damping element is returned to its first end position remote from the piston so that it moves back into the correct starting position during the next following retraction movement Fig. 1 stands and thus the full damping length 41 is available.

The cushioning has been described above in connection with the approach of the piston 4 to the piston rod 8 facing away from the end piece 3. The conditions at the approach of the piston to the other end part 2 are the same, so that a repeated discussion is unnecessary.

The invention has been described above with reference to a double-acting pneumatic cylinder which operates with a piston rod 8. It is basically too applicable to rodless cylinder, as determined by the Fig. 8 is exemplified.

Rodless cylinders are known in various embodiments. Examples are in the EP 0 260 344 B1 and the US-A 4,373,427 described. In such working cylinders, the peg-shaped damping element is often firmly connected to the end parts of the cylinder, wherein the damping element during the movement of the piston against the end position enters into this. There are, as the US patent shows, reverse constructions have been proposed, but then leads to correspondingly thick end parts. If the damping element is arranged at the respective end part, the space already present in these working cylinders in the piston is advantageously utilized for the pneumatic damping and the end parts can be kept relatively short and independent of the damping length. The invention allows to achieve without extension of the installation length of the cylinder in these cases much longer damping paths as this FIG. 8 it can be seen conspicuously:

From the working cylinder essential parts are explained and designated only for the invention. For the details, reference may be made to the aforementioned references. The tubular cylinder body 51 is closed at the ends by two end parts 52, 53 and encloses a cylinder space in which a piston 54 is guided longitudinally displaceable. The cylinder body 51 is provided with a longitudinal slot through which a web connected to the piston 54 leads outwardly to a power transmission element 55. The longitudinal slot is closed by an elastic sealing band 56 which is in two parts and which Cylinder or pressure chamber 57, 58 seals on both sides of the piston 54 to the outside. Each of the two end portions 52 carries a projecting into the respective cylinder chamber 57 and 58, tubular bearing part 59, which is aligned coaxially with the piston 54. On each bearing part 59 is a sleeve 19 corresponding to the FIGS. 1 to 7 mounted longitudinally displaceable, which is associated with a coaxial cylindrical receiving opening 15 in the opposite end face of the piston 54. The sleeve 19 is as in particular in FIG. 3 represented, designed and stored. The same parts are provided with the same reference numerals and not explained again.

The same applies to the formation of the receiving opening 15 which extends axially into the piston 54 in the form of a blind bore. In the end parts 52, 53 the rohrfömrigen bearing parts 59 each open into a channel 60, which leads to a throttle valve 33, similar to FIG. 2 , leads. Structure and effect of this valve are, as already in the basis of FIG. 2 explained, so that here again a further explanation is unnecessary.

FIG. 8 shows the rodless cylinder in a stroke position in which the forming a damping element left sleeve 19 in the extended end position, that is shown away from the end portion 52. Again, holds a detent or possibly just a frictional engagement between the bearing part 59 and the sliding sleeve 19 formed by this, displaceable damping element in the extended position. Upon movement of the piston in the direction of the left end position to the sleeve 19 is first inserted into the receiving opening 15, whereupon the sleeve itself on the bearing part 59 until it rests against the end part 52 is pushed telescopically. A detent or a simple frictional engagement between the sleeve 19 and the inhibiting means forming O-ring 20 ensures that the sleeve 19 forming the displaceable damping element in a piston movement away from the end portion 52 in the in FIG. 8 shown extended end position is brought back.

The invention has been explained above in connection with a throttle valve 33, which causes the throttling of the flowing out of the respective cylinder chamber pressure medium when the piston approaches an end portion and thus regulates the damping. In particular, in pneumatic cylinders with a longer damping travel, it may be appropriate to provide a pressure relief valve instead of such a throttle valve, as for example. From the US-A 3,196,753 is known. The combination of a prolonged damping stroke by telescoping in the manner described with a pressure relief valve brings a significant improvement in the adjustability of the pneumatic damping. Because pressure relief valves close below a certain set threshold value, it is expedient in this case to use a parallel duct (see channel 40 in FIG Fig. 2 ), via which the residual air is discharged from the damping chamber to the connection channel, so as to ensure rapid achievement of the end position of the piston.

Claims (22)

1. Actuator cylinder with end position damping, with

   • a cylinder body (1) containing a cylinder chamber,

   • two end parts (2, 3; 52, 53) closing off the cylinder chamber at the ends,

   • a piston (4) mounted in the cylinder chamber to be longitudinally displaceable between two end positions and

   • a device for damping the movement of the piston when approaching at least one of its end positions, which has two interacting damping elements (15, 19), one of which is provided on an end part (2, 3; 52, 53) and the other is provided on the piston (4) on its side facing the end part and by means of which a damping chamber, which is connected to a device for the throttled removal of pressure medium enclosed in the damping chamber, can be closed off when the piston approaches its end position,

   • wherein the two damping elements are configured to be inserted axially into one another in the direction of the piston movement and at least one (19) of the damping elements is mounted on the end part (52, 53) or the piston (4) between two axially spaced end positions to be restrictedly longitudinally displaceable in relation to the piston or the end part,
   characterised in that both damping elements are provided with interacting elements in the form of inhibiting elements, under the action of which the longitudinally displaceable damping element (19) can be shifted into a first end position close to the piston (4) or the end part (52, 53) when the piston approaches its end position and can be shifted into a second end position, which is further removed from the piston (4) or the end part (52, 53), when the piston moves away from its end position.
2. Actuator cylinder according to claim 1, characterised in that of the two damping elements one has a receiving opening (15) configured in the end part or the piston and the other has a telescopic damping pin (11, 19; 59, 19), which can be inserted into the receiving opening to form a seal.
3. Actuator cylinder according to claim 2, characterised in that the damping pin has a sleeve (19), which is mounted to be restrictedly axially displaceable on a rod-shaped bearing part (11, 59) projecting axially from the piston or the end part.
4. Actuator cylinder according to claim 3, characterised in that the bearing part is part of a piston rod (8) connected to the piston (4) and guided axially out of the cylinder chamber through an end part.
5. Actuator cylinder according to claim 3, characterised in that the bearing part has a tube (59), which is connected to the associated end part (52, 53) and the interior of which is connected to the device for throttled removal of pressure medium enclosed in the damping chamber.
6. Actuator cylinder according to one of claims 3 to 5, characterised in that in at least one of its end positions the sleeve (19) is mounted on the bearing part to project axially beyond the face of the piston (4) or THE end part (52, 53) facing it.
7. Actuator cylinder according to claim 2, characterised in that the damping pin (11, 19) has associated stop elements restricting its penetration depth into the receiving opening (15).
8. Actuator cylinder according to claim 3 and 7, characterised in that the stop elements have a stop surface (24), which is configured on the sleeve (19) and is arranged to interact with a corresponding stop surface on the end part (2, 3) or the piston (4).
9. Actuator cylinder according to claim 8, characterised in that the stop surface (24) is configured on a ring flange (23) of the sleeve (19).
10. Actuator cylinder according to claim 9, characterised in that when the sleeve (19) is moved completely into the receiving opening (15) the ring flange (23) is received in a depression (25) in the associated face of the end part (2, 3) or piston (4).
11. Actuator cylinder according to one of the preceding claims, characterised in when the piston (4) is standing in the end position the piston substantially abuts against the face side of the corresponding end part (52, 53).
12. Actuator cylinder according to claim 1, characterised in that inhibiting elements are provided, which are formed by a frictionally engaged sliding seat between the two damping elements (15, 19) that can be inserted into one another or between parts connected thereto.
13. Actuator cylinder according to claim 1, characterised in that the inhibiting elements have a releasable catch arrangement between the two damping elements (15, 19) that can be inserted into one another or between parts connected thereto.
14. Actuator cylinder according to claim 12 or 13, characterised in that the inhibiting elements have at least one elastic member (20), which is configured on a damping element (15) and can be brought into frictional engagement with a surface of the other damping element (19) when the piston approaches its end position.
15. Actuator cylinder according to claim 14, characterised in that on its surface the other damping element (19) has a catch means interacting with the elastic member.
16. Actuator cylinder according to claim 15, characterised in that the catch means has a bead (32) or depression arranged on the surface.
17. Actuator cylinder according to one of the preceding claims, characterised in that the longitudinally displaceable damping element (19) is held in frictional or non-positive engagement in its end position removed from the piston or the end part.
18. Actuator cylinder according to one of the preceding claims, characterised in that the device for throttled removal of pressure medium enclosed in the damping chamber contains a pressure control valve.
19. Actuator cylinder according to claim 18, characterised in that the pressure control valve has an adjustable threshold.
20. Actuator cylinder according to claim 17 or 18, characterised in that a pressure medium outlet channel (40) is arranged parallel to the pressure control valve.
21. Actuator cylinder according to one of the preceding claims, characterised in that it is a double-action cylinder with a respective end position damping in both end positions.
22. Actuator cylinder according to one of the preceding claims, characterised in that it is configured without piston rods.

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