Valve for controlling flow of fluid

Abstract

The invention relates to a valve having a valve housing (2), in which a valve unit (13) is arranged, which can be positioned in a closed position (42) and in a maximum open position (43) in the range of a stroke movement (28) that can be caused by a drive (27). The spring device (32) causes the valve unit (13) to assume an intermediate open position (41) when the drive device (27) is deactivated. The spring device (32) comprises a closing spring (32a) acting in the closing direction and an opening spring (32b) acting in the opening direction, which are coordinated with each other with respect to the spring forces (FO, FS) thereof in such a way that the intermediate opening position (41) forms the base position of the valve (1).

Description

Technical Field

[0001] The invention relates to a valve for controlling the flow of a fluid, which has a valve housing that limits a valve cavity, into which a supply channel for supplying fluid and a working channel for enabling the fluid to leave, wherein a supply channel opening of the supply channel is surrounded by a valve seat facing the valve cavity, and a closing surface arranged at the axial front side of a valve unit of the valve is opposite to the valve seat in the valve cavity, wherein the valve unit can be moved axially within the range of a stroke movement oriented in the axial direction of a main axis that can be caused by a driving force of a valve driving device in the valve in a closed position in which the closing surface thereof abuts the valve seat and thereby separates the supply channel from the valve cavity in a fluid-tight manner, or in an open position in which at least one flow connection is released from the valve seat and thereby releases a flow connection between the supply channel and the valve cavity that is continuously fluidically connected to the working channel, and wherein the valve unit is continuously prestressed in the direction of the closed position by a closing spring of a spring device of the valve. Background Art

[0002] This type of valve known from DE 10 2013 011 759 A1 has a valve unit, which is pre-tensioned into a closed position by a closing spring, in which the valve unit is in abutment against a valve seat surrounding the inlet of the supply channel within the valve chamber, and thus prevents the fluid from entering the valve chamber from the supply channel. By manipulating an electric drive device based on an electric function principle, the valve unit can be moved to at least one open position lifted from the valve seat and maintained in the open position, so that the compressed fluid supplied to the supply channel overflows into the valve chamber and can flow out of the valve chamber through a working channel leading to the consumer. Since the valve unit occupies the closed position when the drive device is deactivated, the valve unit is a "normally closed" type valve. Due to the required flow requirements, such a valve has energy disadvantages in applications where it is usually necessary to maintain the open position significantly longer than maintaining the closed position, because the drive device must be activated for a correspondingly long time respectively. The valve described in WO 2017 / 080602 A1 belongs to the same subject.

[0003] DE 2 208 183 A1, DE 297 23 707 U1, DE 10 2014 220 222 A1, EP 0 611 349 B1 and EP 0 698 738 B1 also describe electrically actuated valves of the “normally closed” type.

[0004] In EP 1 959 177 B1 and US 6 367 766 B1, valves of the "normally open" type are described, which occupy an open position enabling a fluid flow when the drive is deactivated. However, a particularly high drive force must be applied here to maintain the closed position, because not only must the spring force of the opening spring acting continuously in the opening direction be overcome, but also the fluid pressure acting on the valve unit in an open manner must be overcome. Relying on a weaker spring to remedy this technical problem may no longer guarantee reliable opening when the drive is deactivated. The reduction of the opening force due to the fluid pressure can only be achieved when the nominal width is significantly reduced and the flow value is correspondingly smaller. Summary of the invention

[0005] The object of the present invention is to provide measures which enable energy-saving and reliable operation of the valve while achieving high flow rates.

[0006] In a valve in combination with the features mentioned at the outset, this object is achieved in that, in addition to the closing spring, the spring device has an opening spring which permanently pretensions the valve unit in the direction of at least one open position, wherein the closing spring and the opening spring, which acts in this respect in opposite directions, are coordinated with one another with regard to their spring forces in such a way that the valve unit assumes a basic position which is an intermediate open position between the closed position and the maximum open position in the absence of a drive force from the drive device.

[0007] In this way, there are valves of a type that can be referred to as "normally partially open". When the drive is deactivated, i.e., when no drive force is applied to the valve unit from the drive, a spring arrangement with a closing spring acting in a closed manner and an opening spring acting in an open manner holds the valve unit in an open position referred to as an intermediate open position, in which a fluid flow from the supply channel into the valve chamber is possible, but with a lower flow rate than in the maximum open position. The intermediate open position of the valve unit is a stroke position in which the closing force generated by the closing spring and the opening force generated by the opening spring are equal, whereby a force zero point can be said to exist. In order to close or open the valve further from the intermediate open position, a mutually opposing drive force is required, which should be applied by the drive, but which is smaller than a drive force of a similar nominal width that should be applied in a pure "normally closed" valve or a pure "normally open" valve.

[0008] Advantageous developments of the invention emerge from the dependent claims.

[0009] In principle, the valve can be designed as a valve actuated by fluid force and in particular pneumatically, which has a correspondingly designed drive. However, valve designs are preferred, whose drive is an electrically actuable design and which can be referred to as an electric drive. In particular, an electric drive based on the Lorentz force or an electromagnetic drive based on magnetic resistance is used.

[0010] In order to close the valve starting from the intermediate open position of the valve unit in the case of an electrically actuated drive, a current can be advantageously generated in the coil arrangement of the drive, which generates a force acting in the closing direction and presses the valve unit against the valve seat against the spring force of the opening spring acting in the opening direction. In order to open the valve again starting from the closed position, the driving force acting in the closing direction can be reduced or removed. When the intermediate open position is reached, the direction of the current in the coil arrangement can be reversed, so that a driving force acting in the opening direction is generated, which now works against the closing spring and opens the valve further beyond the intermediate open position.

[0011] Since the valve unit must be displaced from the intermediate opening position by a smaller stroke than the maximum possible stroke for the closing process, the actuating force to be applied is correspondingly smaller, so that even with large nominal widths there is no risk of overheating due to electrical energy input. The same applies to holding the valve unit in any open position beyond the intermediate opening position, wherein the cooling effect caused by the through-flowing fluid is also increased here.

[0012] In one embodiment which is considered particularly suitable, the drive device has a first drive part formed by an electrical coil arrangement and a second drive part which interacts with the energized coil arrangement in order to generate a drive force acting on the valve unit in the axial direction of the main axis. One of the two drive parts is located at the valve unit and the other at the valve housing. In this way, for example, a solenoid valve or an electrokinetic action principle, preferably a moving armature principle or a moving coil principle, can be realized.

[0013] The valve expediently comprises control electronics designed to actuate the drive. In conjunction with the electrical drive, the control electronics are in particular designed such that they can cause the drive to be energized, which selectively has a current direction acting on the valve unit in an opening manner or a current direction acting on the valve unit in a closing manner, so that the valve unit can be closed or opened further starting from an intermediate open position by selecting the respective current direction. If a stroke movement over the entire stroke between the closed position and the maximum open position is desired, the control electronics can reverse the current direction when passing through the intermediate open position.

[0014] Advantageously, the control electronics of the valve can cause the drive to be energized with variable current intensity in both current directions. In this way, any partial opening position between the closed position and the maximum opening position can be adjusted steplessly. Preferably, such a valve can be operated as a proportional valve.

[0015] In particular, the control electronics are integrated into the valve housing or are mounted externally on the valve housing. However, the control electronics can also be implemented as a separate component. For example, the control electronics contain a circuit board equipped with a microprocessor.

[0016] In order to achieve an exact setting of the desired stroke position and the correspondingly desired flow rate, it is expedient for the valve to have a position detection device, by means of which a stroke position of the valve unit that can be assumed within the range of the stroke movement of the valve unit can be detected. In particular, the position detection device is connected to an optional control electronics system, which can process the position data of the valve unit provided by the position detection device as feedback information.

[0017] The control electronics preferably has a regulating function. In this way, the drive can be controlled in a position-controlled manner based on the position data that can be obtained with the help of the position detection device. The position detection device preferably has at least one Hall sensor or another measuring device for determining the stroke position, wherein the other measuring device can also be designed for laser-based or ultrasound-based position detection, for example. The position detection device preferably has the function of a displacement measuring system designed for continuous position detection.

[0018] Preferably, the two springs of the spring device, which act on the valve unit in opposite directions, are designed in such a way with respect to force that the valve unit in the intermediate opening position at least substantially assumes a half-open position, in which the flow cross-section available for the fluid through the supply channel inlet is approximately or exactly half of the maximum flow cross-section released in the maximum opening position of the valve unit.

[0019] In particular, the valve unit in the intermediate open position assumes a travel position in which the valve unit is only just above a closing point in which a closing surface of the valve unit contacts a valve seat fixed to the housing.

[0020] Suitably, the closing spring and the opening spring are respectively compression springs. Such a structural form is preferred over the structural form of the return spring. In particular, the closing spring and the opening spring are helical springs.

[0021] In order to predetermine the desired intermediate opening position, the closing spring and the opening spring are expediently designed in such a way that they have force-displacement characteristics and / or winding pitches that are coordinated with one another and expediently differ from one another.

[0022] An embodiment is considered particularly advantageous in which the closing spring and the opening spring are designed as separate, separate springs of the spring arrangement. This facilitates a coordinated design of the spring forces on both sides and enables a particularly space-saving arrangement in the valve housing, in particular in this regard, so that the opening spring coaxially surrounds the closing spring or vice versa.

[0023] Alternatively, the spring device can have only one single spring element, which is cut off from the valve unit at a point between its two end regions, wherein the cut-off point is selected according to the desired spring force ratio. For example, a central cut-off can be achieved by fastening the valve unit at the relevant point to a single spring element, wherein the length section of the one-piece spring element axially adjoining the cut-off point on both sides serves in one case as an opening spring and in another case as a closing spring.

[0024] In a configuration that is considered to be advantageous, the valve unit has a cap-shaped front end section with a front bottom wall that carries the closure surface, a sleeve-shaped side wall that extends axially away from the bottom wall and away from the internal supply channel opening, and a ring-disk-shaped support wall that protrudes radially outward from the side wall at an axial distance from the front bottom wall. In this case, the closing spring is arranged so that the closing spring is surrounded by the sleeve-shaped side wall and is supported on the one hand at the bottom wall of the valve unit and on the other hand at a support body that is arranged axially opposite to the bottom wall and is fixed to the housing. The opening spring is arranged so that the opening spring surrounds the sleeve-shaped side wall and is supported axially on the one hand at the valve housing within the valve chamber and on the other hand at the support section of the valve unit. The sleeve-shaped side wall is radially between the closing spring and the opening spring, wherein the closing spring is surrounded by the opening spring in a coaxial arrangement over at least a portion of its structural length.

[0025] Preferably, the valve unit is constructed in multiple parts and has a one-piece valve unit main body, on which a preferably disk-shaped sealing element is arranged as a further component of the valve unit on the front side facing the internal supply channel opening, which defines a closing surface that cooperates with the valve seat.

[0026] Expediently, the closing surface of the valve unit is formed on a sealing element composed of a rubber-elastic material.

[0027] In principle, the present invention can be implemented in valves of any function. It has proven to be particularly advantageous to combine the design according to the present invention with a 2 / 2-way valve. The present invention can be implemented in a switching valve and in a proportional valve.

[0028] The valve seat can be formed directly on the valve housing. Preferably, the valve seat has a collar-like, axially convex structure, wherein the valve seat defines an annular sealing edge against which the closing surface rests in the closed position of the valve unit.

[0029] In an advantageous design of the present invention, the valve seat is located at a sleeve-shaped valve seat element independent of the valve housing, the valve seat element is coaxially oriented with the main axis, and the valve seat element is inserted into the inner end section of the supply channel with a variable axial position with respect to the main axis and fixed in a fixed manner at the housing. When assembling the valve, the axial position of the valve seat element with respect to the valve housing can be adjusted variably, and in the adjusted theoretical position, the axial position is fixed to the valve housing in an immovable manner. For example, the valve seat element can be pressed into the end section of the supply channel with a variable pressing depth. Additionally or alternatively, adhesive fixing or screw fixing can also be considered. The variability of the axial position during valve assembly provides an advantageous possibility for calibration in order to compensate for geometric component tolerances and spring tolerances. If the valve has an electrical drive, the valve seat element and therefore the valve seat can be moved within the valve housing, for example, so long or so far, until the desired flow rate is achieved in a given current.

[0030] In particular, in order to achieve a relatively large nominal width and nevertheless keep the actuating force to be applied low, it is advantageous to provide special pressure compensation measures with respect to the valve unit. In this regard, it is expedient for the valve unit to have a compensation surface oriented axially opposite to the closing surface, which defines a compensation chamber formed in the valve housing and which is continuously connected to a region axially upstream of the closing surface via at least one compensation channel running through the valve unit. As a result, in the region upstream of the closing surface and in the compensation chamber, at least substantially the same fluid pressure is always present, thereby producing compensation of the pressure acting axially on the valve unit.

[0031] If the compensation surface of the valve unit is advantageously at least substantially and preferably just as large as the surface of the opening of the internal supply channel that can be covered by the valve unit (i.e. the surface surrounded by the valve seat), at least substantially complete pressure compensation can be achieved. The pressure compensation takes effect in the closed position and in every open position of the valve unit. Thus, the valve unit can be driven into its stroke movement with very low drive forces and held in a correspondingly adjusted stroke position. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The present invention will be explained in more detail below with reference to the accompanying drawings, wherein:

[0033] Figure 1 A preferred embodiment of the valve according to the invention is shown in longitudinal section, wherein the valve unit is shown in an intermediate open position and wherein the stroke positions assumed by the valve unit in the closed position and in the maximum open position are additionally indicated in dash-dotted lines, and

[0034] Figure 2 Shows Figure 1 An exploded isometric view of the valve shown in FIG. DETAILED DESCRIPTION

[0035] The valve, which is designated as a whole by the reference numeral 1 , has a valve housing 2 , which is preferably constructed in multiple parts and has a valve chamber 3 in its interior.

[0036] A plurality of valve channels 4, 5 which penetrate the valve housing 2 and through which fluid can flow, open into the valve chamber 3, the valve channels being, for example, a supply channel 4 and a working channel 5. At their opposite end regions, the supply channel 4 opens via an external connection opening 4a and the working channel 5 via an external connection opening 5a to the outside 6 of the valve housing 2, so that in particular there is the possibility of connecting respectively continuous fluid lines.

[0037] During operation of the valve 1 , the supply channel 4 is connected via its external connection opening 4 a to an external pressure source P which provides a fluid under pressure, wherein the fluid is in particular compressed air.

[0038] During operation of the valve 1 , the working channel 5 is fluidically connected via its external connection opening 5 a to a consumer A, for example a fluid-actuated drive.

[0039] The valve 1 controls the fluid flow between the supply channel 4 and the working channel 5, that is, the fluid flow through the valve chamber 3. The valve 1 selectively allows blocking (that is, closing the fluid connection between the supply channel 4 and the valve chamber 3), or releases the fluid connection, as a result, the compressed fluid can overflow from the supply channel 4 through the valve chamber 3 into the working channel 5.

[0040] The supply channel 4 opens into the valve chamber 3 with an internal channel opening, which is referred to below for better distinction as the supply channel opening 7. The supply channel opening 7 is located in the region of the bottom surface 3a of the valve chamber 3 and is surrounded by an annular valve seat 8 facing the valve chamber 3. The valve seat 3 is expediently designed to be raised in a collar-shaped manner with respect to a surface section surrounding the bottom surface 3a of the valve seat.

[0041] The valve 1 has an imaginary main axis 10 . The supply channel opening 7 and the valve seat 8 are oriented in the axial direction of the main axis 10 , wherein the supply channel opening and the valve seat are arranged in particular coaxially thereto. The bottom surface 3 a extends in particular in a plane orthogonal to the main axis 10 .

[0042] The working channel 5 opens into the valve chamber 3 at a distance from the supply channel opening 7 and in particular laterally, wherein the corresponding channel opening of the working channel is referred to as the working channel opening 12. The fluid connection between the valve chamber 3 and the working channel 5 is permanently open, while the fluid connection between the supply channel 4 and the valve chamber 3 can be controlled by means of a valve unit 13 of the valve 1.

[0043] The valve 1 of this embodiment is designed as a 2 / 2-way valve, but a structure with different valve functions is also possible, for example, a structure with a 2 / 3-way valve function. In particular, in such a case, the valve 1 can undoubtedly also have one or more additional valve channels that lead into the valve chamber 3.

[0044] The valve unit 13 preferably has an elongated form and exemplarily has an imaginary longitudinal axis 14 coinciding with the main axis 10 .

[0045] In this embodiment, the valve chamber 3 is formed by the axial end region of a blind hole-like receiving recess 16 of the valve housing 2, into which the valve unit 13 is inserted. The valve unit 13 has an axial front side 15, with which the valve unit faces forward toward the valve chamber 3. In addition, the valve unit 13 has an axial rear side 19 opposite to the axial front side 15 in the axial direction of the main axis 10.

[0046] The receiving recess 16 is axially delimited internally by a bottom surface 16a formed on the valve housing 2, which forms the bottom surface 3a of the valve chamber 3. On the outer side axially opposite to the bottom surface 16a, the receiving recess 16 is closed by a closure element 11, for example, in the form of a cover, of the valve housing 2. The valve unit 13 is axially located between the bottom surfaces 3a, 16a and the closure element 11, wherein the closure element delimits the valve chamber 3 on the side axially opposite to the bottom surface 16a.

[0047] The valve unit 13 has an axially oriented end face on its axial front side 15, which forms a closing face 26 facing the supply channel opening 7 and the valve seat 8. Under the influence of a drive device 27 of the valve 1, the valve unit 13 can be driven into a linear stroke movement 28, which is oriented in the axial direction of the main axis 10 and is indicated in the figure by a double arrow. In this case, the valve unit 13 can be selectively moved backwards away from the valve seat 8 in a first movement direction 28a pointing forward in the direction of the valve seat 8 or in a second movement direction 28b opposite to this. For this purpose, the drive device 27 can exert a correspondingly oriented drive force on the valve unit 13.

[0048] Within the scope of the stroke movement 28, the valve unit 13 can be positioned in different stroke positions. One of these stroke positions is from Figure 1The open position, which is indicated in addition by a dash-dot line and is referred to as the intermediate open position 41 , can be seen in FIG. 1 , in which the valve unit 13 is lifted with its closing surface 26 from the valve seat 8 , but by less than the maximum possible amount.

[0049] Further possible travel positions of the valve unit 13 are a closed position 42 and an open position referred to as a maximum open position 43, which are located between Figure 1 The same is indicated by corresponding dotted lines.

[0050] In the closed position 42, the valve unit 13 rests with its closing surface 26 on the valve seat 8 in a sealing manner and at the same time covers the supply channel opening 7. In this way, the supply channel 4 is separated from the valve chamber 3 and the working channel 5 which is continuously connected to the valve chamber in a fluid-tight manner in the closed position 42 of the valve unit 13.

[0051] The distance between the valve seat 8 and the closing surface 26 measured in the axial direction of the main axis 10, which is also referred to as the axial distance, determines the free flow cross section available for the transfer of fluid or fluid pressure medium between the supply channel 4 and the valve chamber 3. This free flow cross section determines the flow rate of the overflow fluid, which can also be referred to as the flow rate.

[0052] In the maximum open position 43 of the valve unit 13 , the closing surface 26 is arranged at the greatest possible axial distance from the valve seat 8 . This greatest possible axial distance is greater than the axial distance between the closing surface 26 and the valve seat 8 in the intermediate open position 41 .

[0053] In the maximum open position 43 of the valve unit 13, the maximum released flow cross section is available for transferring the fluid pressure medium supplied to the supply channel 4 to the valve chamber 3. In the intermediate open position 41 of the valve unit 13, the released flow cross section is smaller than the maximum flow cross section.

[0054] By correspondingly actuating the drive device 27 , the valve unit 13 can be selectively positioned at least in the closed position 42 , the maximum open position 43 or the intermediate open position 41 .

[0055] If the valve 1 is designed as a switching valve, the positionability of the valve unit 13 is expediently limited to these three stroke positions. Preferably, however, in accordance with the illustrated embodiment, the valve 13 is designed as a continuously adjustable proportional valve, wherein the valve unit 13 can also be positioned (in particular continuously) in any other opening position, which can be referred to as a partially open position, between the closed position 42 and the maximum open position 43 in addition to the intermediate open position 41. In these other partially open positions, the distance between the closing surface 26 and the valve seat 8 is greater or smaller than in the intermediate open position 41.

[0056] The exemplary valve unit 13 has a pot-like shape with a bottom wall 17 associated with the axial front side 15 and a hollow cylindrical side wall 18 projecting from the bottom wall 17 in the direction of the axial rear side 19. The pot shape defines a valve unit interior 22 that faces away from the valve chamber 3 and is also separated in this respect.

[0057] The valve 1 is equipped with a spring device 32, which is coupled between the valve unit 13 and the valve housing 2 with respect to the force flow. When the drive device 27, which has already been described above, does not exert a driving force on the valve unit 13, the valve unit 13 is held in the intermediate open position 41 by the spring device 32. In other words, the intermediate open position 41 represents the basic position of the valve unit 13, which the valve unit 13 occupies when the drive device is deactivated. Therefore, when the drive device 27 is deactivated, the valve 1 is (only) partially open, so that it can be referred to as a new type of "normally partially open" valve.

[0058] This function is produced by the special design of the spring device 32. The spring device 32 has a closing spring 32a on the one hand and an opening spring 32b on the other hand. The closing spring 32a is a spring that acts on the valve unit 13 permanently in the direction of the closed position (i.e., exemplarily in the first direction of movement 28a) with a spring force that can be referred to as a closing force FS. The opening spring 32b is a spring that acts on the valve unit 13 permanently in an open manner (i.e., exemplarily in the second direction of movement 28b) with a spring force that can be referred to as an opening force FO. The valve unit 13 is therefore continuously loaded in mutually opposite directions of the main axis 10 by spring forces FS, FO, which are provided on the one hand by the closing spring 32a and on the other hand by the oppositely acting opening spring 32b.

[0059] The closing spring 32a and the opening spring 32b (which are also referred to as springs 32a, 32b in the joint naming) are coordinated with respect to their spring forces FS, FO so that the valve unit 13 assumes the described basic position, i.e. the intermediate open position 11, without an effective drive force of the drive 27. In this basic position or intermediate open position 41, there is a force balance between the two springs 32a, 32b at the valve unit 13, so that it is a force zero point, as it is possible, since no resultant spring force acts on the valve unit 13 in the axial direction of the main axis 10.

[0060] Each of the two springs 32 a , 32 b is supported on the one hand on the valve unit 13 and on the other hand directly or indirectly on the valve housing 2 .

[0061] Although it is in principle possible to implement one or both of the springs 32 a , 32 b as compression springs, expediently, in accordance with the illustrated exemplary embodiment, the springs are mechanical springs 32 a , 32 b .

[0062] According to the embodiment shown, the drive device 27 is preferably an electrically actuatable design. By applying an electrical actuation voltage, the drive device 27 can cause a drive force acting on the valve unit 13 in the axial direction of the main axis 10, which causes the valve unit 13 to move in a first direction 28a or in a second direction 28b while overcoming the spring forces FS and FO of the two springs 32a, 32b, and by means of this drive force, the valve unit 13 can be held in the adjusted stroke position as long as desired. Depending on the direction of action, the drive force of the drive device 27 adds to the closing force FS or the opening force FO.

[0063] Preferably, the electrically actuatable drive device 27 has a first drive component 34 and a second drive component 35 that interacts with the first drive component 34 to generate a drive force. One of the two drive components 34, 35 is arranged on the valve unit 13, and the other of the two drive components 34, 35 is arranged on the valve housing 2. By way of example, the first drive component 34 is located on the valve unit 13 and the second drive component 35 is located on the valve housing.

[0064] One of the two drive components 34, 35 is advantageously designed as an electrical coil device 34a which can be energized by applying the actuation voltage. The stroke position temporarily assumed by the valve unit 13 relative to the valve seat 8 depends on the magnitude and polarity of the actuation voltage applied to the electrical coil device 34a. The selected polarity determines the current direction of the current flowing through the coil device 34a and accordingly determines the direction of action of the drive force that can be generated.

[0065] By way of example, the first drive element 34 is a coil arrangement 34a. By way of example, the same coil arrangement is arranged at the valve unit 13 and is carried in particular by the side wall 18 of the valve unit. The coil arrangement is therefore always involved in the stroke movement 28. The coil arrangement 34a cooperates with a second drive element 35 which is fixed in position relative to the valve housing 2 when it is energized.

[0066] Preferably and in accordance with the illustrated embodiment, the drive device 27 is an electrodynamic drive device 27. In this case, the second drive part 35 comprises a permanent magnet device 35a cooperating with a coil device 34a according to the electrodynamic principle.

[0067] By way of example, the permanent magnet arrangement 35a is sunk into the valve unit interior 22 from the axial rear side 19. For example, the permanent magnet arrangement is arranged on a support projection 20 of the closure element 11, which extends centrally into the receiving recess 16 and is designed, for example, in the form of a rod. In particular, the permanent magnet arrangement 35a consists of at least one and, by way of example, exactly one annular magnet 44 coaxial to the main axis 10, which is axially flanked on both sides by annular disk-shaped ferromagnetic flux conducting disks 45.

[0068] Preferably, the second drive part 35 also includes a ferromagnetic non-return sleeve 46 which is fixed in position relative to the valve housing 2 and is coaxially inserted into the receiving recess 16 and radially surrounds the valve unit 13 on the outside. The non-return sleeve 46 is preferably used at the same time as a guide element for radially supporting and linearly guiding the valve unit 13 during the stroke movement 28. Preferably, the valve unit 13 has radially on the outside a plurality of annular belt-like guide ribs 47 which are axially spaced apart from each other and which slidably rest against the inner circumference of the non-return sleeve 46. Preferably, the coil arrangement 34a having at least one coil section 48 consisting of a wound wire is arranged axially between the guide ribs 47.

[0069] When the coil arrangement 34a is energized, the charge carriers flowing therein cooperate with the permanent magnet magnetic field of the permanent magnet arrangement 35a, thereby generating a so-called Lorentz force, which acts as a driving force for the valve unit 13. The direction of the current specifies the direction of action of the Lorentz force and thus the driving force, while the current strength determines the magnitude of the driving force.

[0070] By way of example, the electric drive 27 is designed as a moving coil drive. However, a design as a moving magnet drive with an interchangeable arrangement of the two drive elements 34 , 35 and a permanent magnet arrangement 35 a participating in the stroke movement 28 is also possible.

[0071] According to an exemplary embodiment (not shown), the second drive element 35 is designed as a ferromagnetic device instead of the permanent magnet device 35 a, which interacts with the coil device 34 a according to the reluctance principle.

[0072] It should be understood that other structural forms of the drive device 27 may also be provided to actuate the valve unit 13 .

[0073] Preferably, the valve unit 13 is constructed in multiple parts, wherein the valve unit has, in particular, a one-piece valve unit base body 48, which is equipped with a sealing element 49 composed of an elastomer material or another rubber-elastic material at the axial front side 15. By way of example, the pot-shaped shape of the valve unit 13 is predetermined by the shape of the valve unit base body 48. The bottom wall 17 of the valve unit 13 consists of a bottom section 48a of the valve unit base body 48 and a sealing element 49 attached to the bottom section 48a at the front and on the outside.

[0074] Preferably, the sealing element 43 is disc-shaped. In this embodiment, the sealing element is snapped into the bottom section 42a, but it can also be bonded or welded, for example, in addition or alternatively. In any case, the elastically yielding sealing element 43 is supported by the bottom section 42a of the valve unit base body 42 in the axial direction of the main axis 10.

[0075] The closing surface 26 is formed on the sealing element 43. The closing surface 26 is expediently limited to a central region of the front end face of the sealing element 49, which faces forward. The outer diameter of the sealing element 49 is generally larger than the outer diameter of the closing surface 26. In this regard, the closing surface 26 is surrounded by an annular surface section of the front end face of the sealing element 49, which extends radially outwards to the radial outer circumference of the sealing element 49.

[0076] The valve 1 expediently contains control electronics 52 which are designed to electrically actuate the drive 27. The control electronics 52, which are only schematically indicated, are expediently integrated into the valve housing 2, but can also be arranged outside the valve housing 2, wherein the control electronics can be mounted on the valve housing 2 or arranged separately in this respect.

[0077] The control electronics 52 is designed to energize the drive device 27 and is connected to the coil arrangement 34a, for example, via at least one electrical control line 53. The control line 53 is particularly flexible, so that the permanent magnet arrangement 35a can participate in the stroke movement 28 without hindrance. The control electronics 52 can cause the already explained variable energization with a variable current intensity and a variable current direction. Operating information for the control electronics 52, in particular setpoint position information for a desired stroke position of the valve unit 13, can be input at an electrical input 54 of the control electronics 52.

[0078] The valve 1 is expediently equipped with a position detection device 55, which is also only schematically indicated, and which comprises, by way of example, a permanent magnet 55a arranged at the movable valve unit 13 and a Hall sensor 55b arranged in a fixed position at the valve housing 2 and there, for example, at the closure element 11. By cooperating with the permanent magnet 55a, the Hall sensor 55b can detect the stroke positions of the valve unit 13 that can be assumed within the scope of the stroke movement 28, wherein in particular, each stroke position including the closed position can be detected steplessly. The position detection device 55 is electrically connected to the control electronics 52 via at least one feedback line 56 in order to supply it with the determined position data.

[0079] The control electronics 52 expediently have a regulating function which enables the drive 27 to be actuated in a position-controlled manner and accordingly allows the valve unit 13 to be positioned very precisely in the desired setpoint stroke position.

[0080] Preferably, the spring device 32 acting on the valve unit 13 is designed so that the valve unit 13 in the intermediate open position releases a flow cross section for the fluid through the supply channel opening 7 which is at least substantially and preferably exactly half of the maximum flow cross section released in the maximum open position of the valve unit. In this case, in the non-actuated operating state, the valve unit 1 is half open. However, it should be understood that, depending on the respective application, the spring device 32 can be designed in any other way in order to keep a specific desired flow cross section open in the intermediate open position.

[0081] The desired design of the spring device 32 can be simply carried out by selecting mutually coordinated force-displacement characteristic curves and / or turn pitches for the closing spring 32a and the opening spring 32b. For example, the two springs 32a, 32b are designed differently from each other, in particular, so that the closing spring 32a has a steeper spring characteristic curve than the opening spring 32b.

[0082] By way of example, the force design of the spring device 32 is advantageous in that the closing spring 32a and the opening spring 32b are separate springs 32a, 32b of the spring device 32 that are different from each other. In this way, each spring 32a, 32b can be manufactured and provided as an independent component independently of the respective other spring 32a, 32b. However, in principle, there is the possibility of providing a single one-piece spring element as the spring device 32, which is connected to the valve unit 13 at a location that is spaced apart from the two axial spring ends and can be referred to as a cut-off location, so that one of the length sections of the spring element that is axially connected to the cut-off location on both sides forms the closing spring 32a, and the other forms the opening spring 32b.

[0083] Preferably, the two springs 32a, 32b are configured as compression springs. This applies to the illustrated embodiment and also to the advantageous design of the two springs 32a, 32b as helical springs. Accordingly, by way of example, the closing spring 32a and the opening spring 32b are configured as helical compression springs. Related to this is the advantageous possibility of carrying out a coaxial arrangement of the two springs 32a, 32b, which is also implemented in this embodiment, wherein one of the two springs 32a, 32b coaxially surrounds the other of the two springs 32a, 32b over at least part of the length. In other words, the two springs 32a, 32b overlap in the axial direction of the main axis 10.

[0084] By way of example, the closing spring 32 a has a smaller diameter than the opening spring 32 b , wherein the opening spring 32 b surrounds the closing spring 32 a at a radial distance.

[0085] The front end section 58 of the valve unit 13 having the closing surface 26 preferably has a cap-shaped form. The front end section 58 comprises a bottom wall 17 which is preferably designed with a circular contour, a sleeve-shaped side wall 59 which extends from the edge of the bottom wall 17 in the direction of the axial rear side 19 and thus axially away from the supply channel opening 7, and an annular support wall 60 which is arranged coaxially at an axial distance from the bottom wall 17 on the side wall 59 and protrudes radially outward from the side wall 59.

[0086] The sleeve-shaped side wall 59 and the support wall 60 are components of the side wall 18 of the overall pot-shaped valve unit 13. A sleeve-shaped supporting wall 62 adjoins the support wall 60 toward the axial rear side 19 and also forms a section of the side wall 18 and carries the first drive part 34.

[0087] The bottom wall 17 and the sleeve-shaped side wall 59 together limit the length section of the valve unit interior 22. A closing spring 32a is arranged in the valve unit interior 22, which is therefore radially surrounded on the outside by the sleeve-shaped side wall 59. The closing spring is supported on the one hand on the inner surface of the bottom wall 17 of the valve unit 13 axially opposite to the closing surface 26 and on the other hand on the support body 23 fixed to the housing axially opposite to the bottom wall 17. By way of example, the support body 63 is advantageously formed by a permanent magnet arrangement 35a.

[0088] The opening spring 32b is located outside the valve unit interior space 22 in the valve chamber 3, wherein the opening spring surrounds the sleeve-shaped side wall 59. The opening spring is supported on the one hand on the valve unit 13 and on the other hand on the valve housing 2 in the axial direction of the main axis 10. Preferably, the support is performed at the surface of the support wall 60 facing the bottom surface 16a with respect to the valve unit 13, and at the bottom surface 16a of the receiving recess 16 with respect to the valve housing 2.

[0089] During operation of the valve 1, the valve unit 13 assumes a basic position visible in the figure, which defines an intermediate open position 41, when the drive device 27 is deactivated due to the lack of an existing drive force. Starting from this basic position, the valve unit 13 can be displaced in the direction of the closed position 42, overcoming the spring force FO of the opening spring 32b that acts in an opening manner, or in the direction of the maximum open position 43, overcoming the spring force FS of the closing spring 32a that acts in a closing manner, depending on the current supply direction of the coil device 34a controlled by the control electronics 52.

[0090] If a complete stroke is to be carried out starting from the closed position 42 or starting from the maximum open position 43 to switch into the respective other extreme position, the control electronics 52 causes a reversal of the current direction in the coil arrangement 34 a when passing through the intermediate open position 41 .

[0091] Starting from the closed position 42, the control electronics 52 firstly causes a reduction in the driving force acting in the first direction of movement 28a, wherein after crossing the force zero point in the intermediate open position 41, the current direction in the coil arrangement 34a is reversed, so that a driving force acting in the second direction of movement 28b is generated. Starting from the maximum open position 43, this operating sequence is reversed.

[0092] Preferably, the maximum open position of the valve unit 13 is defined in that the valve unit 13 abuts against a stop 70 fixed to the housing during its stroke movement 28 in the second direction of movement 28b. The valve unit 13 is pressed against the stop 70 by a correspondingly high drive force of the drive 27. The stop 70 is expediently formed by the support body 23. The closed position is produced by the closing surface 26 abutting against the valve seat 8 during the stroke movement 28 in the first direction of movement 28a.

[0093] Preferably, the valve 1 is equipped with means which, at the valve unit 13, bring about compensation of the supply fluid pressure occurring via the supply channel 4 in order to keep the actuation forces for switching and fixing the valve unit 13 as low as possible. These compensation means include a compensation surface 37 formed at the valve unit 13 and oriented axially opposite to the closing surface 26, which is formed at the rear side of the bottom wall 17 in this embodiment and delimits the compensation chamber 24 formed by a part of the valve unit interior 22. The compensation chamber 24 is connected to a region of the valve housing 2 axially upstream of the closing surface 26 via a fluid channel, which is referred to as a compensation channel 36 due to its mode of action.

[0094] By way of example, the compensation chamber 24 is radially delimited by a sleeve-shaped chamber wall 65, which is a component of the valve unit 13 and projects away from the bottom wall 17 in the direction of the axial rear side 19. The compensation chamber is coaxially surrounded by a sleeve-shaped side wall 59. Between the sleeve-shaped chamber wall 65 and the sleeve-shaped side wall 59 there is an annular chamber in which the closing spring 32a extends. At the rear side axially facing away from the bottom wall 17, the compensation chamber 24 is closed by a closure body 66, which is fixed to the housing and is in particular piston-shaped, and which rests in a dynamic seal on the inner circumference of the sleeve-shaped chamber wall 65, which is axially movable relative to the closure body 66. By way of example, the closure body 66 is arranged at the end side on the bearing projection 20.

[0095] In particular, the compensation channel 36 passes through the bottom wall 17 of the valve unit 13, wherein the compensation channel communicates with the compensation chamber 24 on the rear side and opens to the closing surface 26 at its front side via a cut-off opening 38. In this way, the fluid pressure present in the region upstream of the closing surface 26 is cut off by the compensation channel 36, which fluid pressure is thus also present in the compensation chamber 24 with the same magnitude. The closing surface 26 and the compensation surface 37 are therefore loaded with the same pressure, so that pressure compensation occurs. It is particularly advantageous here that the compensation surface 37 is at least substantially and in particular exactly as large as the cross section of the supply channel opening 7 surrounded by the valve seat 8.

[0096] It is expedient to provide the valve 1 with measures which allow simple compensation of possible geometric component tolerances and / or spring tolerances during production. These measures consist in corresponding calibration options. The calibration can be performed by moving the valve seat 8 relative to the valve housing 2 in the axial direction of the main axis 10 in order to change the axial distance from the bottom surface 16a.

[0097] In a calibration method which can be carried out during the manufacture of the valve 1 , the valve seat 8 is axially displaced until a desired flow rate is achieved at a given current intensity of the current flowing through the coil arrangement 34 a , which is measured during the calibration method.

[0098] By way of example, the movability of the valve seat 8 for calibration is achieved in that the valve seat 8 is constructed on the end side at a sleeve-shaped valve seat element 67 which is independent of the valve housing 2 and oriented coaxially with the main axis 10. The valve seat element 67 is inserted into an inner end section 68 of the supply channel 6 opposite to the external connection opening 4a in an axial position that is variable with respect to the axial direction of the main axis 10 and is fixed to the housing. During calibration, the valve seat element 67 can be moved relative to the valve housing 2 in the axial direction of the main axis 10 within the scope of a calibration movement 69 indicated by a double arrow, and can be moved linearly in particular. In the ready-to-operate finished state of the valve 1, the adjusted use position of the valve seat element 67 with respect to the valve housing 2 is locked so that no undesired position changes can occur.

[0099] By way of example, the valve seat element 67 is pressed into the inner end section 68 of the supply channel 4 with a variable pressing depth and fixed in a force-fitting manner. Alternatively or additionally, an adhesive connection can be provided for fixing. It is also possible, for example, to design the valve seat element 67 as a screw element with an external thread, which is screwed into an internal thread formed in the inner end section 68. In this case, when the desired use position is reached during calibration, the screw connection is permanently locked in a suitable manner.

[0100] In an advantageous calibration process, the coil arrangement 34a is energized with a preset current intensity and a preset current direction by means of the control electronics 52 or an external current source, so that the valve unit 13 assumes a certain stroke position due to the sum of the adjustment forces acting on the valve unit, i.e. the driving force generated by the applied current and the closing force FS and the opening force FO of the two springs 32a, 32b, and then the valve seat element 67 is adjusted relative to the valve housing 2 in the axial direction of the main axis 10 by a calibration movement 69 until the desired flow rate occurs. Any desired flow sensor is used for the flow measurement during calibration.

[0101] To summarize briefly again, in the illustrated embodiment, the valve unit 13 is continuously loaded by the closing spring 32a with a spring force acting in the first direction of movement 28a, referred to as the closing force FS, and is continuously loaded by the opening spring 32 with a spring force acting in the second direction of movement 28b, referred to as the opening force FO. The intermediate open position 41 of the valve unit 13 is located at a point where the closing force FS and the opening force FO are equally large, taking into account the spring characteristic curves of the two springs 32a, 32b. Thus, the intermediate open position 41 serving as the basic position can be preset as desired by designing the two springs 32a, 32b in a corresponding manner coordinated with one another. This can be done in particular within the scope of calibration during the manufacture of the valve 1.

[0102] Optionally, the valve 1 can be equipped with adjustment means which allow the spring pretension of the closing spring 32 a and / or the opening spring 32 b to be subsequently varied, so that the basic position can also be varied and adjusted as required even after the valve 1 has been completed.

Claims

1. A valve for controlling the flow of a fluid, comprising a valve housing (2), the valve housing limiting a valve chamber (3), into which a supply channel (4) for supplying the fluid and a working channel (5) for enabling the fluid to leave the valve chamber open, wherein: The supply channel opening (7) of the supply channel (4) is surrounded by a valve seat (8) facing the valve chamber (3), and a closing surface (26) arranged at the axial front side (15) of the valve unit (13) of the valve (1) is opposite to the valve seat in the valve chamber (3), wherein the valve unit (13) can be axially moved within the scope of a stroke movement (28) oriented in the axial direction of the main axis (10) and can be caused by a driving force of a drive device (27) of the valve (1) in a closed position (42) in which the closing surface (26) of the valve unit (13) abuts against the valve seat (8) and thereby separates the supply channel (4) from the valve chamber (3) in a fluid-tight manner, or between at least one position in which the valve seat (8) is lifted and thereby the supply channel (4) is released and the valve chamber (3) is continuously fluidically connected to the working channel (5). The invention relates to a valve unit (13) comprising a first valve element (24) and a second valve element (25) comprising a first valve element (26) and a second valve element (27) which are connected to the valve unit (13) via a first spring (32a) and a second spring (32b ...

2. The valve according to claim 1, characterized in that The drive device (27) is of electrically actuatable design.

3. The valve according to claim 1 or 2, characterized in that: The drive (27) is designed as an electric drive (27).

4. The valve according to any one of claims 1 to 3, characterized in that The drive device (27) comprises a first drive component (34) formed by an electrical coil device (34a) and a second drive component (35) which interacts with the energized electrical coil device (34a) in order to generate a drive force acting on the valve unit (13) in the axial direction of the main axis (10), wherein one of the two drive components (34, 35) is arranged on the valve unit (13) and the other of the two drive components (34, 35) is arranged on the valve housing (2).

5. The valve according to any one of claims 1 to 4, characterized in that The valve has control electronics (52) which are designed to actuate the drive (27).

6. The valve according to claim 5 in combination with any one of claims 2 to 4, characterized in that The control electronics (52) is designed to energize the drive device (27), wherein, by energizing, a current direction acting on the valve unit (13) in an opening manner and a current direction acting on the valve unit (13) in a closing manner can be generated in the drive device (27), preferably with a variable current intensity in each case.

7. The valve according to any one of claims 1 to 6, characterized in that The valve has a position detection device (55) for detecting a stroke position that the valve unit (13) can assume within the scope of the stroke movement (28), wherein the drive device (27) can advantageously be controlled in a position-controlled manner based on position data that can be obtained with the aid of the position detection device (52).

8. The valve according to any one of claims 1 to 7, characterized in that In the intermediate opening position (41), the valve unit (13) releases a flow cross section for the fluid passing through the supply channel opening (7), which flow cross section is at least substantially half of the maximum flow cross section released in the maximum opening position (43) of the valve unit (13).

9. The valve according to any one of claims 1 to 8, characterized in that The closing spring (32a) and the opening spring (32b) are respectively compression springs.

10. The valve according to any one of claims 1 to 9, characterized in that The closing spring (32a) and the opening spring (32b) are respectively coil springs.

11. The valve according to any one of claims 1 to 10, characterized in that The closing spring (32a) and the opening spring (32b) have force-displacement characteristic curves and / or turn pitches that are coordinated with each other and in particular different from each other.

12. The valve according to any one of claims 1 to 11, characterized in that The closing spring (32a) and the opening spring (32b) are designed as separate, individual springs (32a, 32b) of the spring device (32) that are separate from one another.

13. The valve according to claim 12, characterized in that In the closing spring (32a) and the opening spring (32b), one of the two springs (32a, 32b) coaxially surrounds the other of the two springs (32a, 32b).

14. The valve according to claim 12 or 13, characterized in that The valve unit (13) comprises a cap-shaped front end section (58) with a front bottom wall (17) having the closing surface (26), a sleeve-shaped side wall (59) extending axially away from the supply channel opening (7) from the front bottom wall (17), and an annular support wall (60) protruding radially outwards from the sleeve-shaped side wall (59) at an axial distance from the front bottom wall (17). The closing spring (32a) is surrounded by the sleeve-shaped side wall (59) and is supported on the one hand on the bottom wall (17) of the valve unit (13) and on the other hand on an axially opposite support body (23) fixed to the housing, and the opening spring (32b) surrounds the sleeve-shaped side wall (59) and is supported within the valve chamber (3) on the one hand on the valve housing (2) and on the other hand on a support wall (60) of the valve unit (13).

15. The valve according to any one of claims 1 to 14, characterized in that The valve unit (13) has a valve unit main body (48), on the front side of which, facing the supply channel opening (7), a separate sealing element (49) of the valve unit (13) having the closing surface (26) is arranged.

16. A valve according to any one of claims 1 to 15, characterized in that The closing surface (26) is formed on a sealing element (49) of the valve unit (13) which is composed of a rubber-elastic material.

17. A valve according to any one of claims 1 to 16, characterized in that The valve (1) is designed as a 2 / 2-way valve, in particular, the valve is a proportional valve.

18. A valve according to any one of claims 1 to 17, characterized in that The valve seat (8) surrounding the supply channel opening (7) is constructed on a sleeve-shaped valve seat element (67) which is independent of the valve housing (2) and oriented coaxially with the main axis (10), and the valve seat element is inserted into an inner end section (68) of the supply channel (4) in a variable axial position with respect to the main axis (10) and is fixed to the valve housing (2) in a manner fixed to the housing.

19. A valve according to any one of claims 1 to 18, characterized in that The valve unit (13) has a compensating surface (37) oriented axially opposite to the closing surface (26), which limits a compensating chamber (24) constructed in the valve housing (2), which is continuously connected to a region axially upstream of the closing surface (26) via at least one compensating channel (36) which passes through the valve unit (13) and opens to the closing surface (26) by means of at least one cut-off opening (38), wherein the compensating surface (37) is expediently the same size as the surface of the supply channel opening (7) of the supply channel (4) which can be covered by the valve unit (13).

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