EP2047109A1

EP2047109A1 - Valve device having a soft start function

Info

Publication number: EP2047109A1
Application number: EP07801493A
Authority: EP
Inventors: Jakob Brenner; Grzegorz Bogdanowicz
Original assignee: Festo SE and Co KG
Current assignee: Festo SE and Co KG
Priority date: 2006-09-29
Filing date: 2007-08-02
Publication date: 2009-04-15
Anticipated expiration: 2027-08-02
Also published as: CN101517244A; CN101517244B; ATE450715T1; DE102006046450B3; DE502007002215D1; WO2008040411A1; EP2047109B1

Abstract

The arrangement has a pressure pilot valve (25) for influencing a switching position of a main valve (24) to produce a fluid pressure pilot signal. The pressure pilot signal is pressurized to an operating surface of the main valve to switch the main valve from a basic position into a soft start position. A shifting valve (26) is operatable by a secondary pressure dominant in a secondary channel and applies a fluid pressure pilot signal of another operating surface of the main valve with a predetermined level of the secondary pressure.

Description

Valve device with soft start function

The invention relates to a valve device with soft start function, ie a function that allows a gradual, non-sudden pressure build-up on the secondary side.

From DE 91 05 458 Ul such a valve device is known which has a composed of several individual valves soft start valve. A shut-off valve designed as a two-position valve is switched into the connection between a primary channel connected to a pressure source and a secondary channel connected to the consumers to be supplied and can optionally shut off the connection (basic position) or release it (working position). The changeover to the working position is brought about within a certain period of time after actuation of a pilot control valve which is switched on in the course of a soft-start channel which bypasses the main valve and which also has throttling means. Via a branch of the soft-start channel, the secondary pressure prevailing in the secondary channel is also connected to the main valve as a control pressure effective in the direction of the working position.

From activation of the pilot valve, the secondary channel is throttled via the soft start channel fed with pressure medium from the primary channel. Thus, a gradual increase in pressure takes place in the secondary channel. Does the secondary pressure have a reached certain height, the main valve switches to the working position, so that subsequently the secondary channel is fed through the larger flow cross-section of the main valve until the secondary pressure has finally reached the level of the primary pressure.

In the known valve device, for example, a short-term pressure drop in the secondary channel attributable to pressure fluctuations can lead to the main valve switching to the basic position and the system thus again being in the soft start mode for a while. This can lead to significant functional impairment, because the connected consumers can not be temporarily supplied with the necessary amount of fluid. Furthermore, a relatively large-sized pilot valve is necessary to ensure the required even under the circumstances even in the soft start phase increased flow, which leads to large overall dimensions of the soft-start valve.

A soft-start device known from DE 20 2004 015 468 U1 has a similar structure. A shut-off valve can be switched by the gradually building secondary pressure from a closed basic position to an open working position. The secondary-side pressure buildup is predetermined by a throttle device which is turned on in a soft start channel surrounding the shut-off valve. The device is started by simultaneous actuation of two further valve devices, which are switched on in the course of the channel, and by means of which venting of the soft-start device is also possible.

The US 5,669,422 discloses a soft-start valve with a see between three positions switchable main valve. Switching from a home position to a soft start position becomes caused by a pilot valve. Switching from the soft start position to a working position causes the gradually building secondary pressure, which constantly acts on the main valve from the soft start position.

It is the object of the present invention to provide a valve device which includes a reliable, yet compact, soft-start function.

This object is achieved with a valve device incorporating a soft-start valve comprising:

lo - a switchable between a basic position, a soft start position and a working position main valve which separates a secondary channel of a primary pressure under pressure pressure medium leading primary channel in the initial position, which connects in the soft start position the secondary channel via i5 containing a throttle means soft start channel away with the primary channel , And that in the working position, bypassing the throttle means a connection between the secondary channel and the primary channel unlocks, - provided for influencing the switching position of the main valve

2o pilot valve, upon actuation of which a fluid pilot signal is generated which acts on a first actuation surface of the main valve in order to switch the main valve from the basic position into the soft start position, and - a secondary pressure prevailing in the secondary passage

25 engageable switching valve, which switches at a predetermined level of the secondary pressure generated by the pilot valve fluid pilot signal of a second actuating surface of the main valve to switch the main valve from the soft start position to the working position. The main valve of the soft-start valve is thus designed at least as a three-position valve, which in addition to the basic position and the working position can also assume a responsible for the soft start phase SoftStart position. While in the prior art the soft-start fluid flow is routed through the pilot valve and around the main valve, it flows through the main valve according to the invention and does not require direct control by the pilot valve. Responsible for the various switching positions of the main valve is the preferably electrically operable pilot valve in cooperation with the additional changeover valve. The fluid pilot signal generated by the pilot valve switches the main valve to the soft start position. If, after a certain period of time, the secondary pressure has reached the desired switching threshold, it causes the switching valve to actuate the fluidic pilot signal of another actuating surface, so that the main valve is switched from the soft start position into the working position ensuring a greater flow rate.

Preferably, the change-over valve can be actuated fluidically, wherein the secondary pressure can be applied directly to it as a control pressure. The changeover valve can in this case, for example, work in the manner of a pressure compensator. Alternatively, only an indirect activation of the switching valve by the secondary pressure would be possible by an electrically activated switching valve is used, the switching signal is generated in cooperation with a pressure sensor or pressure switch which detects the secondary pressure. The latter enables a particularly simple variation of the switching threshold.

Since the secondary pressure does not act directly on the main valve itself as actuation pressure, this results in a Decoupling of the switching force for the main valve supplying pilot signal. As a result, an interconnection is possible in which occurring during the working position in the primary channel and / or in the secondary channel pressure fluctuations do not affect the switching position of the main valve. This allows undisturbed, continuous operation until the pilot valve is switched off.

Advantageous developments of the invention will become apparent from the dependent claims.

It is expedient to design the main valve so that it causes a pressure relief of the secondary channel in its normal position, thus causing a venting of the secondary channel in pneumatic application. Relief through the main valve eliminates the use of a separate vent valve or vent through the pilot valve.

The responsible for the speed of pressure build-up in the secondary channel throttle means are formed suitably adjustable in their throttling intensity. For example, the throttle means include a throttle screw which is adjustably screwed into the valve housing.

Main valve, pilot valve and changeover valve are preferably summarized to form the soft start valve forming assembly. This simplifies handling during installation and removal.

The pilot valve is in particular a solenoid valve. However, other electrically activatable valves can also be used, for example piezo valves or electrostatic valves. It is expedient if the two actuating surfaces of the main valve point in the same direction. The switching from the basic position to the soft start position and from the soft start position to the working position takes place here with 5 rectified switching movements, which are in particular of a linear nature.

The main valve expediently contains a main valve member which can be positioned in a corresponding number of switching positions to specify its switching positions, in particular in the form of a valve slide. For switching, the first and second actuating surfaces each drively cooperate with the main valve member.

While the second actuating surface responsible for switching to the working position is preferably arranged stationarily on the main valve member, the first actuating surface responsible for switching to the soft start position is expediently provided on a separate actuating element with respect to the main valve member. This actuator is decoupled from the main valve member such

20 that the latter can be switched to the working position without entrainment of the actuating element. Thus, while switching over from the basic position to the soft start position expediently both actuating surfaces are moved together, when switching over to the working position, the first beta remains

25 plane back, and the second actuating surface moves away from her.

Reason for the aforementioned movement is expediently the presence of a arranged in the adjustment of the actuating element stop surface, which defines the Softstartstel 3o ment. The actuating element is preferably designed as an actuating piston. Alternatively, however, would be conceivable, for example, a realization as an actuating diaphragm.

Advantageously, the main valve member is biased by a preferred mechanical return spring means in the basic position. After switching to the soft start position, the return spring device is compressed by a certain amount, the degree of compression increasing even further until the working position is maintained. After deactivation of the pilot valve, the return spring means provides for a provision of the main valve member in the normal position.

The loading of the first actuating surface with the pilot pressure is expediently carried out directly via a control channel controlled by the pilot valve. The application of the second actuating surface is expediently carried out via a switchover from the pilot channel switching channel, in the course of which the switching valve is turned on, which is able to either shut off the switching channel or unlock.

The Umsehaltventil expediently contains a movable Umschaltventilglied. This is controlled and actuated on the basis of the secondary pressure. Direct pressurization by the secondary pressure, if necessary, can be done, for example, by means of a tap channel which is connected to the secondary channel or to the channel branch of the softstart channel extending between the secondary channel and the throttle means.

The valve device can consist exclusively of the soft-start valve. The soft-start valve can be operated as a single valve and, for example, as a switch-on valve within a so-called maintenance device used for compressed air preparation.

In a particularly advantageous embodiment, in addition to the soft-start valve, the valve device contains a fluid distributor which carries the soft-start valve and which is additionally equipped with a plurality of control valves which are supplied together with pressure medium from a distributor feed channel of the fluid distributor. In this case, the soft-start valve is installed so that its secondary channel communicates with the distributor feed channel and thus a controlled pressure build-up in the distributor feed channel can be carried out. In this case, the primary channel can be connected to a distributor supply channel which opens out to the outer surface of the fluid distributor and via which the connection of the pressure source supplying the primary pressure can take place. However, it is also possible to connect the pressure source directly to a corresponding orifice of the primary channel on the soft-start valve.

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

Figure 1 in perspective a preferred

Embodiment of the invention equipped with a soft-start valve device according to the invention,

2 shows the valve device of Figure 1 in the region of the soft-start valve in cross section according to section line

II-II, the main valve being shown when the basic position is taken, Figure 3 is a representation comparable to Figure 2, wherein the

Main valve is shown when taking the soft start position, and

Figure 4 is a representation comparable to Figure 2, wherein the main valve is shown when taking the working position.

In FIGS. 2 to 4, the channels running within the soft-start valve are, for the sake of better clarity, partially depicted only as dotted or solid lines. The solid lines represent channels that are currently under pressure.

The apparent from the drawing, designated in its entirety by reference numeral 6 valve means is formed as a valve battery containing a one-piece or, preferably, modular fluid distributor 7, which is equipped with a plurality of electrically actuated control valves 8.

The control valves 8 are seated in the drawing covered by them Bestückungsflächen where open in the fluid distributor 7 extending channels, which are connected to the not further apparent valve channels of the control valves 8 in a conventional manner.

The channels extending in the fluid distributor 7 include a distributor feed channel 12 extending along the fluid distributor 7 and two first or second distributor relief channels 13, 14 parallel thereto. These channels 12, 13, 14 are in the region of the aforementioned assembly surfaces with each of the control valves 8 in fluid communication. Both Manifold relief channels 13, 14 are in the case of operation with compressed air to venting channels.

From each placement place go through the fluid distributor 7 passing first and second distributor working channel 15, 5 16, are connected to the consumer not shown, for example, by means of fluid power actuated drives. The fluid loading of the distributor working channels 15, 16 is predetermined by the control valves 8, which are electrically actuated via an electrical signal transmission device 17, which is indicated only schematically and is expensive in the fluid displacement 7.

The fluid distributor 7 is equipped in addition to the control valves 8 with at least one soft start valve 21. Its preferred construction is shown in particular in FIGS. 2 to 4. It is expediently attached to a mounting surface 18 located on the outside of the fluid distributor 7 in a preferably detachable manner. However, direct integration into the fluid distributor 7 would also be possible.

The loading area 18 for the soft-start valve 21 expediently adjoins the row of juxtaposed loading areas for the control valves 8, in particular lying in a common plane.

On the mounting surface 18 for the soft start valve 21 is a comparable constellation of mouths of

25 in the fluid distributor 7 extending channels, such as on the mounting surfaces for the control valves 8. Thus, the mounting surface 18 can be used either for the assembly with a soft start valve 21 or at least one control valve 8. If necessary, an adapter may be used

3o be switched. When equipped with a soft-start valve 21, the one distributor working channel 15 functions as a distributor supply channel 22, via which the pressure medium required for the operation of the valve device can be supplied from the outside. The distributor supply channel 22 ends on the opposite side of the mounting surface 18 with a feed opening 23 to a readily accessible outer surface of the fluid distributor 7. At this feed opening 23 can be connected by means of suitable fastening means, a fluid line which connects to a pressure source, which supplies the mentioned printing medium. The fed-in pressure medium is under a predetermined by the pressure source or one of these downstream pressure regulator pressure, which is referred to below as the primary pressure.

With a corresponding embodiment of the soft-start valve 21, the other distributor working channel 16 could alternatively or additionally be used as a distributor supply channel 22.

With the aid of the soft-start valve 21, it is possible, during commissioning of the valve device 6, to produce a slow, gentle build-up of pressure in the distributor feed channel 12 which supplies the control valves 8. The distributor feed channel 12 is not supplied with pressure medium in a conventional manner directly via a connection opening from an outer surface of the fluid distributor 7, but rather from the distributor supply channel 22 via the soft start valve 21.

The soft-start valve 21 is functionally divided into a plurality of individual valves, which, however, are combined to form a unit that can be handled in a uniform manner to form the soft-start valve 21. The soft start valve 21 contains in this sense a main valve 24, a pilot valve 25 and a switching valve 26th

The soft start valve 21 is activated by the pilot control valve 25, which can act directly on the one hand and indirectly, with intermediate switching of the switching valve 26, indirectly fluidly on the main valve 24 to specify one of a total of three possible switching positions of the main valve 24. The pilot valve 25 is of the electrically actuated type and has an electrical interface 27, via which it can be supplied with the required electrical actuation signals. Notwithstanding the provided in the embodiment, independent of the electrical signal transmission device 17 electrical supply of the pilot valve 25, this can also be connected to the electrical signal transmission device 17 in a modified embodiment.

The main valve 24 has an elongated valve housing 28, in which an elongated, a valve member receiving 32 defining cavity is formed. The valve member receptacle 32 includes an elongated, in the direction of its longitudinal axis 31 linearly displaceable main valve member 33. With the resulting, indicated by a double arrow switching movement 34, the main valve member 33 and thus the main valve 24 can be switched between a total of three to be explained in more detail switching positions. The main valve member 33 is designed in particular in the manner of a valve spool.

By sealing means 35 which are fixed to the housing in the valve member receptacle 32 and consist, for example, of a plurality of axially spaced-apart annular sealing elements which coaxially surround the main valve member 33, the valve member receptacle 32 is subdivided into a plurality of axially successive sections 36a, 36b, 36c, of which in each case a valve channel passing through the valve housing 28 leaves. These valve channels include a primary channel 1 communicating with the manifold feed channel 22, a secondary channel 2 communicating with the manifold feed channel 12, and a soft start channel 3 connected within the valve housing 28 to the secondary channel 2. The connection to the manifold feed channel 22 and the manifold - Lo feed channel 12 happens because the primary channel 1 and secondary channel 2 open to an outside of the valve housing 28 arranged installation surface 37, with which the soft start valve 21 is attached to the mounting surface 18. The channel mouths on the installation surface 37 are distributed so that they are aligned correctly with the channel mouths of the distribution channels.

The communicating with the primary channel 1 first portion 36a of the valve member receptacle 32 is axially between the communicating with the secondary channel 2 second portion 36b and 20 communicating with the soft start channel 3 third section 36c.

In the course of the soft start channel 3 throttle means 38 are turned on. They limit the fluid flow through the soft start channel 3 in accordance with the predetermined restriction intensity. Preferably, they are designed adjustable in their throttling intensity, so that the flow rate of the soft start channel 3 can be variably specified.

By way of example, the throttle means 38 include a throttle accessible from an outer surface of the valve housing 28 - 3o screw 38a. The longitudinal section of the main valve member 33 located within the sections 36a, 36b, 36c forms a control section 42 cooperating with the sealing means 35. It is stepped in its longitudinal direction and contains alternately arranged regions of larger and smaller diameters. Depending on whether an area of larger diameter or a region of smaller diameter is arranged at the same axial height with one of the sealing elements, each of axially arranged on both sides of the respective sealing element sections of the valve member receptacle 32 are separated or fluidly interconnected.

The control section 32 is followed on the side of the third section 36c by a drive section 43 of the main valve element 33. At this attacks a Rückstellfederein- direction 44, which biases the main valve member 33 in the direction of an apparent from Figure 2 basic position.

The return spring device 44 is preferably designed as a compression spring device, which expediently coaxially surrounds the drive section 43. It is supported on one end - in the drawing with its right end - on the valve housing 28 and on the other end - with its left end in the drawing - on the main valve member 33. Thus, the main valve member 33 by the spring force constantly, in the drawing to the left directed, charged.

By executing its switching movement 34, the main valve member 33 can be selectively positioned in the basic position shown in FIG. 2, in the soft start position shown in FIG. 3, or in the working position shown in FIG. These positions differ in a different interconnection of the valve channels 1, 2, 3 by the control section 42. In the basic position shown in FIG. 2, the secondary channel 2 is separated from the adjacent primary channel 1. The primary channel 1, like the distributor supply channel 22 which constantly communicates with it, carries a pressure medium which is below the primary pressure.

It is advantageous if the secondary channel 2 is connected in the normal position with a discharge channel 4 of the main valve 33. If compressed air is used as the pressure medium, as is the case in the exemplary embodiment, the drain channel 4 forms an outer surface of the valve housing

28 ausmündenden venting duct, to which a muffler 45 may be connected.

It is expedient if the discharge channel 4 in coaxial extension of the valve member receptacle 32 opens at an end face i5 of the valve housing 28. Alternatively or additionally, it is also possible to guide the discharge channel 4 to the installation surface 37 so that it communicates with one of the distribution relief channels 13 or 14 and an additional or exclusive pressure relief over the

20 fluid distributor 7 can take place.

The primary channel 1 is also separated from the soft start channel 3 in the basic position.

In the soft start position of the secondary channel 2 is exclusively on the soft start channel 3, and thus on the 25 throttle means 38 away, with the primary channel 1 in connection. The connection will be between the first and third section

36a, 36c unlocked. A direct connection between primary channel 1 and secondary channel 2, bypassing the soft start channel 3, is not available. The secondary channel 2 is

30 also separated from the discharge channel 4. In the work position shown in FIG. 4, there is a direct connection between primary channel 1 and secondary channel 2 via the two directly interconnected first and second sections 36a, 36b of the valve member receptacle 32, bypassing the throttling means 38 and hence the soft start channel 3. Es However, it is possible to additionally maintain the connection via the soft start channel 3 as a parallel connection, as is the case in the embodiment. Via the direct connection, a higher fluid flow is possible between primary channel 1 and secondary channel 2 than via soft-start channel 3.

The discharge channel 4 is still separated in the working position of all other valve channels.

The main valve 24 includes a first (46) and a second (47) actuating surface, each drivingly cooperating with the main valve member 33.

The first actuating surface 46 is located on a relative to the main valve member 33 independent actuator 48, which is exemplified in the manner of an actuating piston and which is received axially in the valve member receptacle 32 following the drive portion 43 of the main valve member 33. The first actuating surface 46 has axially away from the main valve member 33, in the drawing to the left.

The actuating element 48 is slidably mounted in the direction of the longitudinal axis 31 of the main valve member 33 in a receiving chamber 52 formed by the end portion of the valve member receptacle 32. With its peripheral wall, it is in sealing contact. The end faces of the Aufnähmekämmer 52 form a main valve member 33 facing the first stop surface 53 and an oppositely oriented second abutment surface

54 for the actuator 48, which limit its displacement.

Instead of actuating piston 48, the actuating element 48 could for example be designed as an actuating diaphragm.

The second actuating surface 47 is axially fixed to the main valve member 33. It therefore makes every linear movement of the main valve member 33 with. It points in the same direction as the first actuating surface 46, in the present case away from the control section 42.

Preferably, the second actuating surface 47 is located on the end face of the main valve member 33 facing the actuating element 48. In the exemplary embodiment, this is the case.

If the main valve member 33 is displaced linearly, it can with its second actuating surface 47 having end portion in the receiving chamber 42 immerse (Figure 2). In addition, the main valve member 33 assume the positions shown in Figures 3 and 4, in which it is completely moved out of the Aufnähmekämmer 52 and its second actuating surface 47 having end portion in a subsequent to the receiving chamber 52 longitudinal portion 55 of the valve member receptacle 32 is located Their cross-section is smaller than that of the receiving chamber 52. Accordingly, the second actuating surface 47 is expediently smaller than the first actuating surface 46th

As long as the main valve member 33 protrudes into the receiving chamber 52, an orien- in the direction of the switching movement 34 Power transmission between the main valve member 33 and actuator 48 is possible. However, these two parts are only loosely against each other, so that only oppressive restoring forces are transferable. On the other hand, this makes it possible for the main valve member 33 to lift off the actuating element 48 and to move away from it, wherein at the same time the distance between the two actuating surfaces 46, 47 changes.

In any case, the main valve member 33 has a the actuation element 48 facing and in particular of the

End face of the main valve member 33 formed Beaufschlagungsfläche 56 which is acted upon by the actuating element 48 mechanically.

The above-mentioned return spring device 44 is located locally between on the one hand the two actuating surfaces 46, 47 and on the other hand the control section 42 on the drive section

43 of the main valve member 33 housed.

To simplify the assembly of the return spring device

44, the main valve member 33 may be made in several parts. Preferably, it has at its the actuator 48 facing the end portion of a plugged and in particular pressed, preferably sleeve-shaped head 57 on which the Rückstellfedereinrichtung can support 44 and mounted by mediating a worn by him annular seal 58 in the longitudinal portion 55 of the valve member receptacle 32 slidably is. The head piece 57 may have at least a portion of the second actuating surface 47.

The actuator 48 divides the receiving chamber 52 in a on the main valve member 33 opposite side lying first actuating chamber 62 and on the main valve member 33 side facing the second actuating chamber 63. The first actuating chamber 62 is opposite to the actuating element 48 by the first stop surface 5 5 limited. The second actuating chamber 63 has axially opposite the actuating element 48 via a rigid boundary wall formed by the second stop surface 54 and also via an axially movable boundary wall, which is formed by the main valve member 33 and lo whose second actuating surface 47. With a corresponding position of the main valve member 33, thus, the second actuating chamber 63 may extend a piece in the longitudinal portion 55, as can be seen from Figure 4.

On the other hand, a fluidic pilot channel 64 branching off from the second section 36b of the valve member receptacle 32 connected to the primary channel 1 opens into the first actuating chamber 62. In the course of this pilot channel 64, the pilot valve 65 is switched on, so that the pilot control valve 64 is switched on.

2o Erkanal 64 is subdivided into a communicating with the primary channel 1 pilot feed channel 64a and communicating with the first actuating chamber 62 pilot control working channel 64b.

In particular, the pilot valve 25 is a 3/2 way valve capable of connecting the pilot working passage 64b to either the pilot feed passage 64a or to a pilot relief vent passage 65 for pressure relieving. The latter can open out via the housing of the pilot valve 25 directly to the atmosphere 3o, as is the case in the embodiment. However, it is also possible to vent via a distributor-venting channel running in the fluid distributor 7. The switching valve 26 includes a preferably linear, according to double arrow 66 movable Umschaltventilglied 67. A preferred mechanical spring means 68 generates a spring force by which the switching valve member 67 is biased in the direction of 5 present in Figures 2 and 3 initial position. The starting position is predetermined by the system of the Umschaltventilgliedes 67 on a housing-fixed stop surface 72. Instead of the mechanical spring device 68, a gas spring device, in particular an air spring device, could also be used.

Together with the housing section enclosing it, the changeover valve member 67 axially delimits a control chamber 73, which is constantly connected to the secondary channel 2 via a tap channel 74 passing through the soft start valve 21. This connection can take place directly or by connecting the tap channel 74 to the channel branch of the soft-start channel 3 extending between the throttle means 38 and the secondary channel 2.

Thus prevails in the control chamber 73 constantly the current 2o secondary pressure. This exerts on the switching valve member 67 of the spring force of the spring means 68 opposite switching force Fu.

The switching valve 26 is able to control the fluid passage through a switching channel 75, over which the

25 control working channel 64 b is connected to the second actuating chamber 63. In the initial position of the reversing valve member 67, the connection is interrupted. Is the switching valve member 67 displaced by a sufficiently high switching force Fu in the apparent from Figure 4 switching position,

3o, the fluid passage through the switching channel 75 is released. A typical operation of the valve device 6 is as follows.

It is assumed that the pilot valve 25 is deactivated and the main valve member 33 is in the basic position. As a result, the secondary channel 2 and thus the associated with this distributor feed channel 12 is depressurized. Via the feed opening 23, a pressure medium which is under a primary pressure and which also rests in the pilot feed channel 64a is fed. The two actuating chambers 62, 63 are vented via the pilot valve 25. This basic state is shown in FIG.

For switching on the valve device 6, the pilot valve 25 is actuated via a supplied electrical control signal. The pilot valve 25 opens the passage through the pilot channel 64, so that a primary pressure corresponding to the fluidic pilot signal is fed to the first actuating chamber 62 and the first actuating surface 46 is applied. As a result of the resulting actuating force, the actuating element 48 is displaced up to abutment against the second stop surface 54, wherein it entrains the main valve member 33, overcoming the spring force of the return spring device 44. If the actuating element 48 has reached the second stop surface 54, the main valve member 33 is in the soft start position shown in FIG.

The changeover valve member 67, which still occupies the initial position, in this case holds the second actuation chamber 63 separated from the pilot control conduit 64.

Starting with the switchover to the soft start position, a soft start phase lasting a certain time begins. This is characterized in that over the unlocked Soft-start channel 3 with throttled flow Pressure medium flows into the secondary channel 2, so that the prevailing secondary pressure gradually increases. The gradient of the pressure increase can be varied via the setting of the throttle means 38.

About the tap channel 74 is the current secondary pressure in the control chamber 73 of the switching valve 26 at. Accordingly, as the secondary pressure increases, the switching force Fu increases, which has no effect as long as a threshold value defined by the spring device 68 is not reached.

When this threshold is reached, the soft start phase ends. The switching force Fu is now sufficiently large to displace the changeover valve member 67 into the changeover position shown in FIG. 4, which has the result that the fluidic pilot signal via the now open switching passage 75 also in the second actuation chamber 63 and thus in the second actuating surface 47 is present. As a result, the main valve member 33 moves further into the working position shown in FIG. 4, the actuating element 48 remaining in place. Since the cross section of the longitudinal section 55 is smaller than that of the first actuating chamber 62, acts on the actuating element 48, a differential force, which holds it in abutment with the second stop surface 54.

By switching to the working position of the secondary channel 2 is supplied via the main valve member 63 unlocked large flow cross section with pressure medium, so that the secondary pressure reaches the height of the primary pressure in a very short time. In the embodiment of the pressure prevailing in the secondary channel 2 pressure the switching valve 26 is switched directly as the switching force supplying control pressure. Alternatively, however, it is also possible, the switching valve 26 to form electrically actuated, wherein the electrical switching signal is generated in cooperation with a pressure sensor or pressure switch, which detects the secondary pressure.

To return to the basic position, only the pilot valve 25 is to be switched off, so that the pilot control working channel 64b is vented. The return spring means 44 then shifts the main valve member 33 back to the home position.

The spring device 68 is expediently designed to be adjustable in terms of its spring force. For this purpose, a knob 76 or other suitable handle may be present.

An advantage of the described valve assembly is the insensitivity of the soft-start valve to pressure fluctuations in the primary channel 1 or secondary channel 2. Should the switching force Fu so far drop because of a pressure drop, that the switching valve 26 switches to the starting position, this does not affect the working position of the main valve member 33 because the pilot control fluid contained in the second actuating chamber 63 remains locked and can not escape.

The valve device 6 can be operated both with gaseous and with liquid media. Compressed air is preferably used.

Claims

claims

A soft start valve device comprising a soft start valve (21) comprising:

- A switchable between a basic position, a soft start position and a working position main valve (24), the

5 in the basic position a secondary channel (2) from a primary pressure under pressure pressure medium leading primary channel (1) separates, in the soft start position the secondary channel (2) via a throttle means (38) containing soft start channel (3) away with the primary channel (1 ) connects, lo and that in the working position, bypassing the throttle means (38) a connection between the secondary channel (2) and the primary channel (1) unlocks,

- One for influencing the switching position of the main valve

(24) provided pilot valve (25), upon actuation i5 a fluidic pilot signal is generated, which is a first

Actuating surface (46) of the main valve (24) acted to switch the main valve (24) from the basic position to the soft start position, and

- A by the secondary channel (2) prevailing secondary 20 pressure actuated changeover valve (26) at a predetermined level of the secondary pressure from the pilot valve

(25) generates a fluidic pilot control signal of a second actuating surface (47) of the main valve (24) in order to move the main valve (24) from the soft start position into the working position.

25 switch position.

2. Valve device according to claim 1, characterized in that the secondary channel (2) in the basic position of Main valve (24) with a discharge channel (4) is connected.

3. Valve device according to claim 1 or 2, characterized in that the throttle means (38) in their Drosselungsin-

5 are formed adjustable intensity.

4. Valve device according to one of claims 1 to 3, characterized in that the main valve (24), the pilot valve (25) and the switching valve (26) are combined to form an assembly.

5. Valve device according to one of claims 1 to 4, characterized in that the pilot valve (25) is a solenoid valve.

6. Valve device according to one of claims 1 to 5, characterized in that the two actuating surfaces (46, i5 47) point in the same direction.

7. Valve device according to one of claims 1 to 6, characterized in that the three switching positions of the main valve (24) are predetermined by corresponding switching positions of a movable main valve member (33), wherein

20, the first and second actuating surfaces (46, 47) are each configured to cooperatively cooperate with the main valve member (33).

8. Valve device according to claim 7, characterized in that the first actuating surface (46) on a respect

25 of the main valve member (33) is formed separate actuating element (48) which upon actuation by the fluidic pilot signal with entrainment of the main valve member (33) until it rests against a soft start position predetermining the striking surface (54) is displaceable, wherein the main valve member (33) of the actuating element (48) away when it is then further moved by the fluid loading of the second actuating surface (47) to the working position 5.

9. Valve device according to claim 8, characterized in that the actuating element (48) is arranged axially adjacent to the linearly displaceable main valve member (33) and in a merely the transmission oppressive actuating forces lo loosely applied way to the main valve member (33).

10. Valve device according to claim 8 or 9, characterized in that the actuating element (48) is designed like a piston.

11. Valve device according to one of claims 7 to 10, characterized in that i5 the second actuating surface (47) is fixedly arranged on the main valve member (33).

12. Valve device according to claim 11 in conjunction with one of claims 8 to 10, characterized in that the second actuating surface (47) of the first actuating

2o surface (46) removed when the main valve (24) from the

SoftStartstellung is switched to the working position.

13. Valve device according to one of claims 7 to 12, characterized by a main valve member (33) biasing in the basic position return spring means (44).

25 14. Valve device according to claim 13, characterized in that the return spring means (44) axially between on the one hand the two actuating surfaces (46, 47) and on the other hand, the switching positions predetermining control section (42) of the main valve member (33) is arranged coaxially on the main valve member (33).

15. Valve device according to one of claims 7 to 14, characterized in that the first actuating surface (46).

5 limits a first actuation chamber (62) which communicates with a pilot control channel (64) delivering the fluid pilot signal and controlled by the pilot valve (25).

16. Valve device according to one of claims 7 to 15, characterized in that the second actuating surface (47) lo limits a second actuating chamber (63), which with a

Switching channel (75) communicates, which communicates with a pilot control channel (64) which supplies the fluidic pilot control signal and is controlled by the pilot control valve (25) and in the course of which the switchover valve (26) is switched on.

17. Valve device according to one of claims 1 to 16, characterized in that the switching valve (26) comprises a biased by a spring force to a starting position Umschaltventilglied (67) which prevail opposite to the spring force of one of the secondary channel (2) -

20 the secondary pressure-dependent switching force is applied.

18. Valve device according to claim 17, characterized in that the switching valve member (67) controls the fluid passage through a switching channel (75), which acts at one end with the fluidic pilot signal of the pilot valve

25 and at the other end leads to the second actuating surface (47), such that the fluid passage in the initial position of the Umschaltventilgliedes (67) shut off and deflected when reaching a secondary pressure of a predetermined height in a switching position Umschaltventilglied (67)

30 is released.

19. Valve device according to claim 17 or 18, characterized in that the spring force of a mechanical, in their spring force in particular adjustable spring means (68) is supplied.

5. 20. Valve device according to one of claims 1 to 19, characterized in that in the secondary channel (2) prevailing secondary pressure the switching valve (26) is switched directly itself as serving to cause the switching force control pressure.

21. Valve device according to one of claims 1 to 20, characterized by a with several control valves (8) equipped fluid distributor (7) containing a distributor feed channel (12) and at least one distributor-discharge channel (13, 14), respectively in fluid communication with the control valves (8) and which is equipped with the soft-start valve (21), the secondary channel (2) with the distributor feed channel (12) and the primary channel (1) with a to the outer surface of the fluid distributor (7 ) outflowing distribution supply channel (22) are connected.

20 22. Valve device according to claim 21, characterized in that the fluid distributor (7) has a plurality of mounting surfaces, each of which two fluid distributor (7) passing through distributor working channels (15, 16) go out and expediently at least partially optional

25 can be equipped with a control valve (8) or with a soft start valve (21), wherein at least one distributor working channel (15), in the case of equipping the associated mounting surface with a soft start valve (21), as a distributor supply channel (22) available is.