EP1130272A2 - Valve - Google Patents

Abstract

The valve has control unit (8) with a valve slider (12), which delivers control forces (S1,S2), to produce switching movements in first (23) and second (24) switching directions and move the valve slider in different switching positions. The movements are assisted by a drive unit with a spring device. In the first switch movement, the slider is moved from a first switching position into an end switching position by an impact device fixed in the casing, in which it is held by the first control force. In the second switch direction, the slider is moved out of the first position by the second control force. At least one drive unit (43) has a spring device (44) to begin the first switch movement through the kinetic energy of the control unit. The spring force (FS) generates the second control force by hydraulically-generated operation forces (FB), to begin the second switching movement.

Description

The invention relates to a valve with a control of valve slides serving fluid flows Control device by applying actuating forces relatively to the valve housing to a first switching direction following first switching movement and an opposite one second switching direction following the second switching movement drivable and therefore in different Switch positions is positionable, being at the first Switchover movement while covering a switchover distance a first switching position in a by means of housing-fixed slings predetermined end switch position can be shifted, in which it acts through the first acting in the first switching direction Actuators can be kept and from them through Application of in the opposite second switching direction acting second actuators within the second Switching movement can be moved out.

A multi-way valve of this type comes from, for example EP 0 678 676 B1. There is the control device from a piston-like valve slide with axially upstream Actuating piston formed and can be acted upon by a Control fluid in two opposite end switch positions be positioned. Depending on the switching position the valve channels of the valve with different configurations fluidly linked.

A problem with all valves of this type is that if the control device remains in one of the End switch positions the static friction between the valve spool and the seals surrounding them rise sharply. This behavior is particularly typical during downtimes from 2 hours. The consequence of this is that the Moving the control device out of the relevant end switch position and to switch to another switch position required actuating forces increase. this in turn leads to the fluidic available Switching resistance opposing actuation forces increased will, so the switching times increase, causing malfunctions for the consumers connected to the valve can cause. The behavior is particularly critical with monostable two-position valves.

It is therefore the object of the present invention to take measures to meet those even after long downtimes Ensure reliable switching behavior of the valve.

This object is achieved by at least one drive device with still ineffective at the beginning of the first switching movement and only during the end section of the first switching movement through the kinetic energy of the control device spring means under tension, their resilience at the beginning of the second switching movement in addition to actuating forces generated by the application of fluid Generation of the second actuating forces contributes.

When switching the control device into a limit switch position thus initially finds a switchover movement more conventional Kind instead. However, the control device has a part the switchover distance in the direction of the end switch position, are given by the existing at this time kinetic energy of the control device spring means at least a drive device is energized. It So energy is transferred to and in the spring means saved. Energy storage in the spring means lasts as long as the control device through on it acting first actuating forces in the end switch position is held. As a rule, these first actuating forces fluidic actuating forces and are used with monostable valves in particular applied by an air spring. Now the Control device for the purpose of moving out of the end switch position in the second switching direction by a Control fluid applied, adds to their actuation forces initially add the resilience of the spring means what is sufficient to overcome the increased static friction and the Switch control device. Switching delays can thus effectively prevented even with longer valve downtimes become.

Advantageous developments of the invention emerge from the subclaims forth.

It is possible to have at least one containing the spring means Provide drive device stationary on the valve housing, wherein the tensioning of the spring means takes place in that the moving control device when approaching the end switch position on one with the spring means in operative connection standing impact surface hits.

Additionally or alternatively, at least one drive device also be provided on the control device, so that they are carried by this and during the switching movements is moved. This type of construction can usually be constructive realize much easier than an integration in the valve housing. Especially when the drive device integrated in a control piston of the control device is a separate with respect to the valve spool Represents part so that it is very simple instead of a conventional one Actuating piston can be used.

The tensioning of the spring means expediently takes place by that the spring means between the moving control device and housing-fixed support means compressed when the control device is at its end switch position approximates. The necessary to tension the spring means Travel distance can be very short and in particular much less than the remaining distance of the switchover distance, where the spring means are still inoperative are and are not yet compressed. This leaves the Control device sufficient time during the switching movement for the construction of the necessary for tensioning the spring means kinetic energy.

The one loaded at the start of the tensioning process and the spring means assigned impact surface is conveniently located on a slidably guided drive tappet Drive device, which is directly in the valve housing or recorded in an adjustable manner in the control device can be.

In order to obtain the desired characteristic, it is expedient provided that the spring means even in the unloaded Condition under a certain bias. Adjustment means can be provided which are variable Allow presetting of the spring means. Such Adjustment means also allow tolerance compensation regarding the length of the spring means, especially if these are formed by at least one mechanical spring. Alternatively or in addition to at least one mechanical The spring means can also spring from a gas spring and thereby preferably be formed by an air spring.

The drive device is expediently an axial one End area assigned to the control device. It is possible in the case of a control device having two end switch positions a drive device in both end switch positions assign, expediently in the area of two axial ends of the control device.

The first actuating forces from a gas spring and thereby preferably formed by an air spring, for example around to choose a monostable two-position valve expediently the circumstances such that the Tension force of the spring means at least approximately the first Corresponds to actuating forces or is slightly lower. To this The first actuating forces can be in the end switch position located control device by the Clamping force be substantially balanced, so that the by actuating forces to be applied in the control fluid essentially only overcome the static friction of the sealing measures must to the control device again from the end switch position switch in a different switch position.

Figur 1

eine bevorzugte Ausführungsform eines mit den erfindungsgemäßen Maßnahmen ausgestatteten Ventils, hier exemplarisch in einer Bauform als monostabiles 5/2-Wegeventil, das Ganze im Längsschnitt und teils schematisiert, und

Figur 2

den in Figur 1 strichpunktiert markierten Ausschnitt II in vergrößerter Darstellung, wobei in durchgezogenen Linien eine Stellung der Steuereinrichtung unmittelbar zu Beginn des Spannens der Federmittel gezeigt ist und wobei strichpunktiert die zugeordnete End-Schaltstellung mit gespannten Federmitteln angedeutet ist.

The invention is explained in more detail below with reference to the accompanying drawings. In this show:

Figure 1

a preferred embodiment of a valve equipped with the measures according to the invention, here exemplarily in a design as a monostable 5/2-way valve, the whole in longitudinal section and partly schematic, and

Figure 2

the detail II marked in dash-dotted lines in an enlarged view, a position of the control device is shown in solid lines immediately at the beginning of the tensioning of the spring means and where the associated end switch position is indicated by tensioned spring means.

The valve 1 shown in the drawing is is a multi-way valve, the concrete example being a 5/2-way valve shows.

The valve 1 has a valve housing 2, the present one contains a main body 3, on its two axial end faces in each case a final body 4, 5 is arranged. Suitable Fastening means for fixing the connecting bodies 4, 5 on the main body 3 are indicated by dash-dotted lines at 6, wherein it is, for example, fastening screws.

Inside the valve housing 2 extends in the Longitudinally an elongated receiving space 7, in which a elongated control device 8 is also housed. The control device 8 contains a piston-like elongate Valve slide 12 and two actuating pistons 13, 14 which the Valve slide 12 upstream on its two axial end faces are.

In the receiving space 7 open laterally, in the longitudinal direction spaced locations, a plurality of valve channels 15, the with the individual valve channels 15 communicating receiving space sections axially on either side of an annular Sealing device 16 are flanked. Between axially adjacent Recording space sections are located in each case only one sealing device 16. The valve slide 12 alternately has larger areas in the longitudinal direction and smaller cross-section, depending on the current axial position of the valve spool 12 with individual in the embodiment Sealing devices 16 fixed to the housing work together or not work together. Exists Sealing contact, they are on both sides of the sealing device in question 16 located receiving space sections fluid-tight separated from each other. However, there is an area smaller diameter of the valve spool 12 on the same Height with a sealing device 16, there is an intermediate space, through which the adjacent receiving space sections are interconnected so that a fluidic Print medium between the communicating thereby Valve channels 15 can overflow.

In the exemplary embodiment, one of the valve channels 15 is a Feed channel P, through which to be distributed by the valve Pressure medium, in particular compressed air, is fed. On both sides a working channel opens adjacent to the feed channel P. A, B in the receiving space 7, these working channels A, B can be connected to a consumer, for example with a pneumatic cylinder. To every working channel A, B closes a ventilation duct axially outwards R, S on.

The sealing devices 16 enclose the control device 8 coaxial, each having a suitable sealing material existing ring-shaped sealing body 17, for example an elastomer body. The sealing body 17 is in the embodiment of an annular, radially after held on the inside open seal housing 18 through which the Sealing device 16 on the inner surface of the receiving space 7 is fixed, for example by pressing.

The sealing contact between a sealing device 16 and the control device 8 is brought about in that the Sealing body 17 a section of larger diameter of the valve spool 12 encloses with sealing contact.

The control device 1 is in the embodiment between two switch positions switchable. The first possible switch position is in Figure 1 below the longitudinal axis 22 of the receiving space 7, while the second switch position follows referred to as the end switch position - above the Longitudinal axis 22 is shown.

In the first switch position takes place in the embodiment the valve channel assignment such that the feed channel P with which is connected to a working channel B while at the same time the other working channel A with the one ventilation channel R communicates. The second ventilation channel S is here cordoned off. In contrast, in the end switch position Feed channel P with the previously vented working channel A connected, while the other working channel B vented via the ventilation channel S, which was previously closed off becomes. Here is the remaining ventilation channel R cordoned off.

The for moving the control device 8 from the first Switch position in the end switch position movement taking place be referred to as the first switching movement and runs in a first switching direction indicated by an arrow 23. Moving the control device 8 out the end switch position is in the first switch position referred to as the second switching movement and takes place in one the first switching direction 23 opposite, likewise second switching direction marked by an arrow 24. Die Switching directions are aligned with the longitudinal axis 22.

The valve of the exemplary embodiment is a monostable valve in the form of the end switch position has a preferred switching position. This will caused that the one on the right in Figure 1 Adjusting piston 13 on its opposite valve spool 12 first application area 25 constantly by a under fluidic fluid at a certain actuation pressure Pressure medium is applied. In the embodiment this fluid pressure medium through a first actuation channel 26 branches off from the feed channel P in the interior of the valve housing 2 and into one of the associated end area of the receiving space 7 formed first application space 27 fed, that of the movable adjusting piston 13 or its first Actuation area 25 is limited.

The control device 8 experiences first actuating forces S ₁ , which are effective in the first switching direction 23, through the pressure medium acting on the first application surface 25.

Due to the constant connection of the first pressurizing chamber 27 to the feed channel P, an air spring results in the exemplary embodiment from the compressed air located in the first pressurizing chamber 27, which constantly applies the first actuating forces S _{1 to} the control device 8.

The opposite axial end of the valve spool 12 assigned second actuating piston 14 is like the other, first actuating piston 13 displaceable in the associated seal End portion of the receiving space 7 out. For sealing An annular sealing device 28 can be provided be in an annular groove of the actuating piston in question 13, 14 sits and with the radially facing inner peripheral surface 32 of the receiving space 7 in sliding sealing contact stands.

The second actuating piston 14 defines, with a second actuation surface 33 axially facing away from the valve slide 12, a second actuation space 34 formed by the associated end section of the receiving space 7. This is connected to the feed channel P via a second actuation channel 35 like the first actuation space 27, whereby it however, it is a controlled connection. The latter results from the fact that in the course of the second actuation channel 35 a pilot valve 36 is switched on, which has an electrically activatable actuation device 37 - for example an electromagnet or a piezo device - by means of which the fluid passage through the second actuation channel 35 can be released or blocked can. When the second actuation channel 35 is blocked, the second pressurizing space 34 is vented by a channel guide, not shown, for example within the actuation device 37. When the connection is released, the channel guide used for ventilation is shut off and instead the second pressurizing chamber 34 is connected to the feed channel P, so that control fluid is fed from the feed channel P into the second pressurizing chamber 34, which actuation forces are indicated by the arrow acting on the second pressurizing surface 33 by an arrow F _B exerts on the control device 8 in the second switching direction 24.

The control fluid could take the place of a branch from the feed channel P can also be fed through a separate control channel, what also for the action on the first actuating piston 13 serving print medium applies.

The receiving space 7 preferably extends in the longitudinal direction through the entire main body 3 and into the two Final body 4, 5 into it. At least most of it the actuating pistons 13, 14 lie within their travel range of the associated end body 4, 5 back, wherein a guide sleeve 38 to obtain an optimal sliding surface coaxially in the respective end section of the receiving space 7 can be used. The actuator 37 is expediently also on one of the end bodies 4 intended.

Is through the actuator 37, the feed of Control fluid in the second pressurizing chamber 34 prevented and the latter is vented, starting from the first Switch position a shift of the control device 8 in the first switching direction 23 until finally the first End switch position is present, which is defined by the fact that the control device 8 with the first stop means provided on it 38 on second stop means 39 fixed to the housing comes to the plant. The latter are in the embodiment of the end face axially facing the control device 8 End surface 41 of the receiving space 7 is formed. The on the Control means 8 provided stop means 38 are in the exemplary embodiment on the actuating piston 14 and are preferred of which the end face 41 faces axially End face 42 formed.

In order to move the control device 8 out of the end switch position and switch it back into the first switch position, the fluid passage through the second actuation channel 35 is released by activating the actuation device 37, which results in the above-mentioned actuation forces F _B acting in the second change-over direction 24 . Together with a clamping force F _S , which will be explained below and act in the same direction, these result in second actuating forces S ₂ , which together are greater than the first actuating forces S ₁ and the static friction forces F _H acting on the control device 8 through the sealing devices 16 in the end switching position. As a result, the control device 8 is switched back to the first switching position without delay.

An essential essence of the present invention lies in the provision of the aforementioned clamping force F _S by a drive device 43 shown enlarged in FIG. 2, which is preferably integrated into the actuating piston 14 as shown and is therefore carried by the control device 8 .

The drive device 43 is equipped with spring means 44 which are put under tension during the course of the first switching movement to generate the tensioning force F _S. However, the arrangement is such that the spring means 44 are ineffective at the beginning of the first switchover movement and preferably during most of the switchover distance and only during the end section of the first switchover movement, i.e. while the section of the switchover section immediately preceding the end switch position is covered Tension. The latter occurs through the kinetic energy of the control device 8, which the control device 8 builds up as it passes through the section of the first switching movement that is not braked by the spring means 44. As long as the control device 8 is held in the end switching position by the first actuating forces S ₁ , the clamping force F _S remains stored in the spring means 44. However, if the fluidic actuation forces F _{B are} added, the control device 8 shifts in the second switching direction 24 due to the excess force, the spring means 44 delivering the stored energy in the form of the tension force F _S to the control device 8 and for an optimal initial acceleration behavior of the control device 8 to care.

The preferred constructive implemented in the exemplary embodiment Solution provides that the drive device 43 in formed the actuating piston 14 forming a base body 45 Contains drive chamber 46, which to the axial end face 42nd is open. A drive tappet is located in the drive chamber 46 47 axially in the direction of the switching movements according to the double arrow 48 adjustable bearings. The also in the drive room 46 housed spring means 44 supported on the one hand on the base body 45 and on the other hand on the drive tappet 47 and apply this to the first one Switching direction 23 rectified extension direction 49. As long the control device 8 assumes the first switching position, the drive plunger 47 in the in FIG Solid positions shown in the basic position held in the one provided on it, oriented in the direction of extension 49 Impact surface 52 with respect to the first stop means 38 at a distance from the end face 41 of the receiving space 7 is upstream. This in Figure 2 with the letter "h" marked distance also forms the maximum possible Tension of the spring means 44.

The basic position of the drive plunger 47 is by each other cooperating and facing first and second Stop surfaces 53, 54 on the drive tappet 47 and on the actuating piston 14 specified.

The drive plunger 47 is stepped in the longitudinal direction and has one provided with the impact surface 52 on the end face Impact section 56, axially against which a stop section 55 larger diameter connects. The first stop surface 53 is on the oriented in the direction of extension 49 and over the Impact section 56 radially projecting end face of the stop section 55 provided while the second stop surface 54 on a coaxially surrounding the impact section 56 and sleeve body protruding into the drive space 46 57 is provided. The spring means 44 are supported on the one hand opposite to the first stop surface 53 oriented back of the stop portion 55 and on the other hand on the inner one opposite this at a distance Boundary surface 58 of the drive space 46.

Opposing the impact surface 52 in the first switching direction 23 is a counter-impact surface fixed to the valve housing 61 provided.

In the first switching position of the control device 8 are both the first and second stop means 38, 39 as well the impact surface 52 and the counter-impact surface 61 with relative arranged at a large distance from each other. The drive tappet 47 assumes the basic position.

Starting from the first switching position, the first switching movement triggered changes in these conditions initially nothing. Although the aforementioned distances decrease, however without mutual contact. The spring means 44 thus have at the beginning of the first switching movement and based on this during the largest Part of the same has no effect.

This changes when the end of the first switching movement the impact surface 52 strikes the counter-impact surface 61. At this point, the first two and the second Lifting means 38, 39 still about the clamping distance h to each other spaced. Because of the kinetic energy of the control device 8 it is not stopped, but moved until the first and second slings come into contact 38, 39 relative to that, in turn, of further movement hindered drive plunger 47 further. Doing so the drive plunger 47 axially relative to the actuating piston 14 in the Drive space 46 pushed in, causing tensioning of the spring means 44 results. The end switch position is therefore characterizes both the impact surface 52 and the counter-impact surface 61 as well as the two attachment means 38, 39 abut against each other, the spring means 44 around the Are stretched h. In Figure 2 are the circumstances the end switch position indicated in dash-dotted lines.

The spring means 44 are tensioned in the exemplary embodiment by compressing them. It is here around one or more mechanical springs, preferably compression springs. However, other types of springs would also be possible one could particularly use a gas spring, preferably in the form of an air spring, with the air cushion for example by branching off compressed air from the Valve 1 running channels can be created.

As long as the control device 8 is in the end switch position, the tensioned spring means 44 bring about the already mentioned spring force F _S via the mutual contact of the impact surface 52 and the counter-impact surface 61, which tends to displace the control device 8 in the second switching movement. However, the clamping force F _S alone is not sufficient to trigger the second switching movement. Only when the actuating device 37 is activated and the actuating forces F _B are also applied by supplying the control fluid, do the second actuating forces S ₂ , which are higher than the first actuating forces S ₁ and the static friction forces F _H , set the control device 8 in the first switching position move back.

The clamping force F _s , however, only acts during the initial phase of the second switchover movement, specifically over a proportion of the switchover distance corresponding to the clamping path h. Even if this clamping path h is very small - it can move, for example, in the order of 5/10 mm, the stored spring energy is sufficient to contribute to overcoming the initially high static friction forces F _H and to set the control device 8 in motion. As soon as the control device 8 moves, the actuation forces F _B are sufficient to move the control device 8 back into the first switching position and to hold it there for as long as desired, despite constant fluid loading of the first loading chamber 27.

The valve 1 is preferably designed in such a way that, based on identical fluid pressures in the two pressurization spaces 27, 34, the tensioning force F _{S of} the tensioned spring means 44 is the same or slightly less than the first actuating forces S ₁ caused by an air spring effect. Despite matching forces, the spring means 44 can be tensioned because the impact surface 52 strikes the counter-impact surface 61 with force due to the initially unimpeded movement of the control device 8 and the spring means 44 can be compressed due to the kinetic energy. The fact that the control device 8 then remains in the end switch position is related to the static friction forces F _H caused by the sealing devices 16. If the control device 8 is then to be switched over, the control pressure fed in via the second actuation channel 35 only has to overcome the static friction F _H , which is readily possible, so that the control device 8 switches over practically without delay.

To specify a desired characteristic of the spring means 44 it is an advantage if this is already in the basic position of the drive plunger 47 under a certain preload stand. In the embodiment, the bias can variable by choosing an appropriate axial mounting depth of the sleeve body 57 with respect to the drive space 46 pretend. The sleeve body 57 thus forms adjusting means here 62 for variable presetting of the spring means 44, the different mounting depths in the present case differently pressing the sleeve body 57 into the Drive space 46 can be realized. Alternatively, it would be for example also possible, the sleeve body 57 as a screw part execute and the mounting depth by changing the Adjust screwing depth as required.

Especially depending on the type of valve spool 12, the drive device 43 could also be different Place as present at an axial end region of the Control device 8 are located. It would also be possible to Control device displaceable between two end switch positions 8 to be equipped with a plurality of drive devices, starting from both end switch positions Support the return movement. This could in particular at both axial end regions of the control device 8 a drive device can be provided in each case.

In an embodiment not shown at least one drive device alternatively or additionally on the valve housing. You can see the arrangement then For example, imagine that the body 45 on the housing side is arranged and the movable impact surface 52nd the counter-impact surface provided on the control device 8 61 protrudes. Here, in particular, would also be the Possibility to use the valve housing 2 immediately Base body for supporting the spring means 44 and optionally to be used to support the drive tappet 47.

One or both actuating pistons 13, 14 could well be such be firmly connected to the valve spool 12 that they each Transfer tensile and compressive forces to the valve spool 12 can. In particular with one provided on an actuating piston However, drive device 43 is one with respect to of the valve spool 12 separate configuration is advantageous, because this is an easy retrofit for conventional valves enabled by simply replacing a conventional one Adjusting piston equipped with a drive device 43 Actuating piston is used.

Claims (17)

Valve, with a control device (8) having a valve slide (12) serving to control fluid flows, which by applying actuating forces (S ₁ , S ₂ ) relative to the valve housing (2) to a first changeover direction (23) following a first changeover direction (23) and a second switching movement following an opposite second switching direction (24) can be driven and can thus be positioned in different switching positions, whereby during the first switching movement it can be shifted from a first switching position to a final switching position predetermined by housing-fixed stop means (39), covering a switching distance which it can be held by first actuating forces (S ₁ ) acting in the first switching direction (23) and from which it can be moved out by applying second actuating forces (S ₂ ) acting in the opposite second switching direction (24) as part of the second switching movement, characterized by at least at least one drive device (43) with spring means (44) which are still ineffective at the beginning of the first switching movement and are only put under tension during the end section of the first switching movement by the kinetic energy of the control device (8), the tensioning force (F _S ) of which at the beginning of the second switching movement in addition to actuating forces (F _B ) generated by the application of fluid, also contributes to the generation of the second actuating forces (S ₂ ). Valve according to claim 1, characterized in that at least a drive device (43) on the valve housing (2) is provided and one with the spring means (44) in operative connection contains standing impact surface on which the control device (8) for tensioning the spring means (44) with a opposite surface can impact. Valve according to claim 1 or 2, characterized in that at least one drive device (43) from the control device (8) is worn and one with the spring means (44) contains an impact surface (52) that is operatively connected, the one for tensioning the spring means (44) to an opposite one counter impact surface (61) fixed to the housing can impact. Valve according to claim 2 or 3, characterized in that the impact surface (52) on a relative to a base body (45) of the drive device (43) in the switching directions (23, 24) movable drive plunger (47) is provided on which are supported on the base body (45) Act on spring means (44). Valve according to claim 4, characterized in that the Base body (45) according to the placement of the drive device (43) from the valve housing (2) or from the control device (8) is formed. Valve according to one of claims 3 to 5, characterized in that that the drive device (43) on or in a in operative connection with the valve slide (12) Adjusting piston (14) of the control device (8) is provided. Valve according to claim 6, characterized in that the Actuating piston (14) and the valve slide (12) as from each other separate parts are formed. Valve according to one of claims 1 to 7, characterized in that that at least one drive device (43) is located at an axial end region of the control device (8). Valve according to one of claims 1 to 8, characterized in that that the control device (8) between two end switch positions is shiftable, in both end switch positions at least one drive device each (43) is effective. Valve according to claim 9 in conjunction with claim 8, characterized characterized in that at both axial end regions Control device (8) each has a drive device (43) is provided. Valve according to one of claims 1 to 10, characterized in that that the spring means (44) constantly under tension stand. Valve according to claim 11, characterized in that Setting means (62) for variably specifying the pretension of the Spring means (44) are present. Valve according to one of claims 1 to 12, characterized in that that the spring means (44) at least one mechanical Feather included. Valve according to one of claims 1 to 13, characterized in that that the spring means (44) at least one gas spring and preferably contain an air spring. Valve according to one of claims 1 to 14, characterized by at least one actuating device (37) for controlling the action on the control device (8) with a control fluid (F _B ) which produces the actuating forces (F _B ) acting in the second switching direction (24). Valve according to one of claims 1 to 15, characterized in that the first actuating forces (S ₁ ) are caused by a gas spring, preferably in the form of an air spring. Valve according to one of claims 1 to 16, characterized in that the tensioning force (F _S ) of the spring means (44) corresponds at least approximately to the first actuating forces or is slightly less.

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