The invention relates to a fluid power arrangement, in particular
a valve assembly, according to the preamble
of claim 1.
Such a fluidic arrangement goes out DE 199 31 235 A1
out. The transmission of energy between a power source and a piezo-electric actuator of a fuel injection valve is wireless by a coupling capacitance is connected between these two components.
A fluidic arrangement in the form of a valve assembly or valve assembly of the U.S. Patent 6,685,159
has a drive device that includes a piezoelectric actuator for influencing a fluid flow, and a drive device for driving the piezoelectric actuator via a wireless interface, for example, with radio-frequency signals, optical signals, infrared signals or based on Low voltage signals works. On the side of the drive means is a transmitter and on the side of the drive means a receiver is present, for example a receiver which converts optical signals to a voltage for driving the piezoelectric actuator. Furthermore, for example, solar cells can be present at the interface. The wireless control of the actuator allows the use of the fluidic device or the valve assembly, for example, in connection with flammable chemicals or the like.
Also from the German patent application DE 41 16 570 A1
is a wireless control of piezo valves ago by means of light. In the German Offenlegungsschrift DE 102 03 765 A1
the inductive non-contact electrical power transmission is proposed for switching a fluidic valve.
in the known solutions
is, however, that comparatively complicated transmitter and receiver circuits
are required to that of the sending drive device
receive wireless signals at the receiver into energy.
DE 100 26 174 A1
shows a capacitive bus, wherein signals via capacitive coupling elements with bus couplers that couple and decouple signals by means of associated capacitive coupling elements.
One out DE 195 12 903 A1
known communication interface between a computer and a vehicle device works capacitively, namely such that a planar functional element of the vehicle device is designed as a counter electrode to an electrode of an externally attachable to the vehicle devices, connected to a computer capacitive coupling adapter.
Out DE 198 56 937 A1
an inductive energy transfer is produced. In series capacitors compensate for a total reactance of a primary conductor loop of the inductive transformer. In consumer-side secondary coils, which are arranged in a vehicle, capacitors are also connected in series, with their reactance corresponds to that of the secondary windings.
At one off DE 103 01 978 A1
known device is transmitted by means of an inductive transformer energy, which is provided, for example, a piezoelectric actuator available.
A converter circuit according to DE 101 47 168 A1
has a storage throttle, which is connected upstream of a primary storage capacity and a secondary storage capacity, in particular a piezoelectric actuator, is connected downstream. By actuating a primary switching element and a secondary switching element, energy can be transferred from the primary storage capacity to the secondary storage capacity and recovered.
is therefore the object of the present invention, a fluid technical
To provide arrangement with a drive device, in which
a piezoelectric actuator over
a wireless interface with no outgoing electrical lines with
Task is in a valve assembly of the type mentioned
that the wireless interface is a capacitive energy transfer
Allows the actor
and that the drive means comprises a first electrode and the drive means
a second electrode of a coupling capacitor of the capacitive interface
The coupling capacitor realized by the wireless interface enables a simple transfer of energy from the drive device to the drive device, so that both the drive device and the drive device can be realized with a few components. The drive device, which is preferably a valve module, can be designed as a type of fully encapsulated unit, without outwardly guided electrical and / or optical lines. The drive device or valve device is suitable for use in the food industry, in the field of chemicals or the like. The cleaning of the whole or substantially ge closed drive device is very simple. In addition, the simply constructed drive device robust.
first electrode is in a housing
the drive means and the second electrode is in a housing of
Drive device integrated. The two electrodes are expediently
on opposite sides
Sides of the two housings
is understood that in the drive device different construction variants
wherein, for example, the drive means as a valve means
or a combined valve actuator device be designed
can. For example, the piezoelectric actuator for driving
serve a fluidic, in particular pneumatic valve,
which forms part of the drive device. There are
both pilot operated and directly controlled valve variants
Furthermore, a fluid power drive, for example a
pneumatic cylinder integrated in the drive device or
be directly attached to this.
Charging or discharging the second electrode is expediently
associated with an actuator stroke of the piezoelectric actuator. Thus, will
so to speak, a 1-to-1 coupling between the second, in the drive device
realized electrode and the piezo-electric actuator realized
so that extra
electrical components are not essential. Indeed
is also a construction variant of the drive device according to the invention conceivable,
in which a transformer assembly by
two or more charge / discharge cycles of the coupling capacitor, so to speak
is charged to the required for switching the piezoelectric actuator switching voltage
Is it possible,
that the drive device also more than a piezoelectric
Preferably, each piezoelectric actuator is a separate capacitive
Interface of the type according to the invention
in the fluid technical invention
Arrangement used components of the wireless interface
easy to implement and, for example, in comparison with coils,
Optocouplers or solar cells inexpensively.
Control device and the drive device can be separate
Building units, in particular modules be. But it is also possible that
the drive device and the drive unit a structural unit
form. The drive device and the drive unit are for example
by corresponding connection means, a total surrounding them
or the like connected to each other.
the control device or the drive device is special
prefers that they are opposite
Temperature fluctuations and / or corrosion resistant, or food safe
are, for example, for processing food
or chemicals are used. For example, the
at least partially made of stainless steel, ceramic or the like advantageous
consist. The above applies in particular to the drive device,
one remote from the control device, only by the
forms a wireless interface with this coupled module.
Control device as well as for
the drive device, it is useful if they are liquid-tight
exhibit. Thus, also a slight cleaning of the respective
Device, in particular the drive device possible.
the first and the second electrode is expediently at least one
Insulation layer, in particular for thermal insulation, available.
Furthermore, it is advantageous between the two electrodes of the capacitive
Interface arranged a dielectric. Thus, the of the
Drive to be provided drive voltage for actuating the
capacitive interface will turn out lower, because the capacity of the capacitive, wireless
Interface through the dielectric is increased. This at least
an insulating layer and / or the dielectric may be, for example
Air, ceramic, plastic or the like included.
piezoelectric actuator is, for example, by charging the
Coupling capacitor of the capacitive interface in one direction,
by unloading in the other direction or in an opposite direction
Thus, the wireless interface is for bi-directional actuation of the
sufficient piezoelectric actuator. But it is also a variant
the non-capacitive triggering for discharging the piezoelectric actuator
Discharge means are present in the drive device. The drive device contains corresponding
Control means for controlling the discharge means, for example
a light source comprising a light-actuated semiconductor switch,
For example, a photo-transistor, the discharge of the discharge circuit
operated for discharging the piezoelectric actuator. Thus, the piezoelectric becomes
Actuator in one direction through the capacitive interface actuated, in
the opposite direction by an optical or other wireless
Way caused discharge.
Be exemplary embodiments of
Invention explained with reference to the drawing. Show it:
1 a first embodiment of a fluidic device according to the invention, in which a piezoelectric actuator of a drive device forms part of a directly controlled fluid-technical, in this case pneumatic valve,
2 an electrical equivalent circuit diagram of the drive device according to 1 .
3a a voltage waveform on the piezoelectric actuator according to 1 applied voltage,
3b a course of the actuator according to 1 driving control voltage,
3c a course of a control pulse for discharging the actuator according to 1 .
4 A second embodiment of a fluidic device according to the invention with a piezoelectric actuator of a drive device, which contains a fluidic, presently pneumatic pilot operated valve,
5 an electrical equivalent circuit diagram of the drive device according to 4 .
6 a voltage waveform of a voltage at the piezoelectric actuator according to 4 and
6b a voltage waveform of a control voltage for driving the piezoelectric actuator according to 4 ,
In the 1 and 4 Inventive fluidic arrangements are shown in a partially highly schematic manner. Partial components of the two arrangements according to 1 and 4 the same or similar, so that in this respect same reference numerals or in 4 opposite 1 around 100 increased reference numerals are used.
1 shows a valve assembly 10 as a first embodiment of a fluidic device according to the invention. A drive device 11 serves to wirelessly drive a drive device 12 via a wireless interface 13 , The drive device 12 in the present case is a pneumatic valve, with which an indicated by arrows fluid flow 14 , z. B. a compressed air flow, a food liquid, a chemical stream or the like can be influenced.
A schematically illustrated piezoelectric actuator with a relative to a base part 16 movable actuator member 17 actuates a valve member 18 that has a fluid channel 19 coming from the fluid flow 14 is flowed through, opens or
closes. The actor 15 is shown very schematically and is realized for example as a bending transducer. In principle, the actuator element could 17 be a valve member at the same time. In the present case, however, the valve member is through the actuator member 17 actuated, for example, directly to the actuator member 17 attached. Particularly preferred is a construction variant, not shown, in which the actuator member actuates the valve member via a lever mechanism.
The drive device 11 actuates the piezoelectric actuator 15 wireless via the capacitive interface 13 on the basis of control commands, which the control device 11 over a bus 20 , for example, an electric or optical bus receives. Preferably, the bus is 20 to a field bus to the other valve arrangements, expediently in the nature of the valve assembly 10 , are docked. interconnectors 21 lead from the bus 20 to a bus coupler 21 the drive device 11 who's on the bus 20 transmitted control commands and receives a voltage converter 23 according to these commands. At the voltage converter 23 it is, for example, a voltage-pulse converter. In any case, the voltage converter generates 23 a switching or control voltage 24 , For example, with the pulse-shaped course according to 3b ,
The control voltage 24 , which is constructed for example to ground, is located on a coupling capacitor 25 who is at the interface 13 is realized, and the connected in series piezoelectric actuator 15 on, a capacitor 26 forms. The voltage converter 23 is, for example, with a first, in the control device 11 contained electrode 27 of the coupling capacitor 25 or the interface 13 connected. The actuator element 17 is with a second, in the drive device 17 contained electrode 28 of the coupling capacitor 25 connected.
By applying the control voltage 24 to the capacitors connected in series 25 . 26 For example, causes the Aktorglied 17 from the base part 16 removed and thus the valve member 18 the fluid channel 19 closes. The deflection of the actuator member 17 towards the closed position is in 1 shown by solid lines.
Now one could, as in the embodiment according to 4 , on the coupling capacitor 25 or the interface 13 apply a control voltage in the opposite direction to the actuator element 17 to move back into the open position shown in dashed lines and the fluid channel 19 to open. According to the embodiment 1 is however, another variant was chosen. The drive device 12 namely contains non-capacitive controllable discharge 29 with a wireless non-capacitive, in this case optically controllable semiconductor switching element 30 , For example, a photodiode. When a drive means included in the drive means 31 in the form of a light source, such as a light emitting diode 32 Generates light, the semiconductor switching element 30 conductive, leaving the actuator member 17 unloaded. The semiconductor switching element 30 allows, for example, a discharge of the actuator member 17 with respect to ground, taking it with the actuator member 17 directly or indirectly, z. B. via the second electrode 28 (as in 1 ) connected is.
3a shows the voltage curve of an actuator voltage 33 at the actuator 15 , Between times "0" and t1 is the control voltage 24 on the actuator 15 on, so the actuator member 17 is deflected. From the time t1, the drive means generate 31 a light pulse 34 such that the semiconductor switching element 30 becomes conductive and the actor 15 discharges.
The drive device 11 and the drive device 12 have separate housing from each other 35 . 36 , The housing 36 is down to connections for the fluid channel 19 completely closed and expediently liquid-tight. Because of the wireless interface 13 are no outward leading wire connections or optical connection lines to the housing 36 necessary. The housing 35 and or 36 are suitably made of stainless steel and / or ceramic and / or plastic.
A temperature-resistant or temperature-fluctuation-resistant design of the housing 35 . 36 is particularly preferred, so that, for example, the drive mechanism direction 12 can also be used in strongly changing temperatures, for example in the food industry. For example, as a fluid flow 14 Any liquid or gaseous medium through the channel 19 to flow through, z. As beer or a cleaning fluid. Unless it is the fluid that is the channel 19 flows through to beer, this is conveniently cold, z. B. 7 degrees Celsius. If the channel 19 however, the corresponding cleaning liquid is preferably hot, e.g. B. 140 degrees Celsius. This means a significant temperature fluctuation, which is the electronic components of the drive device 11 could harm in principle. Since the drive device 11 and the drive device 12 However, thermally decoupled from each other, z. B. present in each case separate units are (suitably in modular design), finds a possible harmful temperature transition of the drive device 12 to the drive device 11 not happening.
The housing 35 . 36 For example, they are at a distance 37 spaced apart. A gap 38 between the housings 35 . 36 can be filled with air, for example. In the present case, the air causes thermal and electrical insulation of the two housings 35 . 36 from each other. The in the gap 38 Air at the same time is a dielectric between the electrodes 27 . 28 ,
In this context, it should be emphasized that expediently the capacity of the coupling capacitor 25
increasing dielectric 39
, For example, air or, suitably, another, a higher dielectric constant exhibiting dielectric, between the electrodes 27
of the coupling capacitor 25
is arranged. This is advantageous because the control voltage 24
by a factor F must be greater than that at the actuator 15
applied actuator voltage 33
calculated as follows:
where CK is the capacitance of the coupling capacitor 25
and CA the capacity of the actuator 15
To increase the actuator voltage 33 on the capacitor 26 or the actuator 15 Optionally an electronic voltage booster circuit 40 be provided, the z. B. in a connecting line 41 between the electrodes 27 . 28 is switched. The voltage booster circuit 40 increases the actuator voltage 33 opposite to the control voltage 24 For example, where two or more voltage strokes of the control voltage 24 in a voltage swing of the actuator voltage 33 is implemented.
The electrodes 27 . 28 are expediently components of the housing 35 . 36 , This is how the electrodes are 27 . 28 relatively large area feasible. For example, the housing 35 . 36 be largely made of metal, with the electrodes 27 . 28 are electrically separated from such housing areas, for example, for contacting the base part 16 and / or the semiconductor switching element 30 , z. B. against mass serve.
In the 4 illustrated valve assembly 100 has partially similar components as the valve assembly 10 , Accordingly, the same or around 100 used increased reference numerals.
In contrast to the valve arrangement 10 has the valve order 100 a pilot operated fluidic valve 140 at their drive device 112 on. Further, no discharge means for discharging a capacitor 126 forming piezoelectric actuator 115 the drive device 112 present, so that consequently the driving device 111 none driving the unloading Drive means in the manner of the drive means 31 Has. Instead, a voltage converter generates 123 a control voltage 124 which are used both for actuating the actuator 115 in Verschließstellung as well as for actuating the actuator 115 in open position is suitable.
The control voltage 124 has, for example, the in 6b shown rectangular or at least substantially rectangular course. At a time "0", the control voltage increases 124 For example, to a value Umax, which in turn to the actuator 115 switched coupling capacitor 25 is applied. This increases the at the actuator 115 applied actuator voltage 133 for example in the in 6a indicated type, wherein the actuator member 17 from the base part 16 removed and the inflow of pilot-pressure air 141 at an inlet 142 (which is indicated only schematically) allows. The incoming pilot-pressure air 141 actuates an actuator or valve member, e.g. B. a membrane 142 to which a valve member 118 is arranged. The valve member 118 then closes a fluid channel 119 that of a fluid 114 , z. As a liquid or gaseous chemical, a food or the like, is flowed through. The drive device 112 forms a valve device.
It is understood that in addition to the membrane 142 Also, another seal, such as a Teflon seal may be present. In any case, it is preferred that the pilot control of the drive device 112 opposite the fluid channel 119 is fluid-tight.
At a time t1, the voltage converter generates 123 the control voltage 124 with the negative voltage value Umin. This causes a falling voltage at the coupling capacitor 25 a decreasing actuator voltage 133 at the actuator 115 , By applying the negative voltage becomes the actuator 115 discharged, so that the actuator member 17 in the direction of the base part 16 and thus can move back to the closed position. This closes the actuator 115 and prevents the pilot-pressure air 141 on the membrane 142 acts.
A return means in the form of a return spring 143 that the valve member 118 is assigned, represents the valve member 118 back in the direction of the open position, allowing fluid 114 through the fluid channel 119 can flow. The return spring 143 For example, it acts on the membrane 142 and rests on a channel wall 145 of the canal 119 from.
The membrane 142 for example, has a stroke of about 3 mm. The pilot-pressure air 141 For example, has a pressure of 5 to 6 bar. The return spring 143 acts, for example, with a force of 30 to 40 N.
The drive device 111 and the drive device 112 are designed as mutually separate modules, each with separate housing 135 . 136 to have. The two housings 135 . 136 are at a distance 37 spaced apart. In a gap 138 between the two housings 135 . 136 there is a ceramic element 139 which has two beneficial effects. The ceramic element 39 , Preferably, a kind of disk, on the one hand forms a dielectric that the capacity of the coupling capacitor 25 increased, so the control voltage 124 can be comparatively low. Furthermore, the ceramic element forms 139 a thermal decoupling of the two devices 111 . 112 , so that thermally stressing influences, for example, by the fluid 114 are caused, essentially only on the drive device or the valve module 112 act and not on the control device 112 thermally transmitted, where more electrically sensitive components, such as the bus coupler 22 , available.
Further expedient between the first and second electrode 27 . 28 Anordenbare insulation layers and / or dielectrics may for example be a PTFE element (PTFE = polytetrafluoroethylene), a plastic element or the like.
The fluidic arrangements according to the invention, which expediently contain one or more flow valves, are particularly suitable for use in the field of food technology. At the drive devices 12 and 112 are expediently flow valves, that is to switching valves and / or throttle valves with which a fluid flow on and off, or can be throttled.