DE10257549B3 - Controllable pneumatic valve incorporated in automobile seat, has setting element provided by parallel sliders coupled via wire sections of shape memory alloy - Google Patents

Abstract

The valve (2) has a setting element (6), used for displacement of a blocking element (4) relative to a valve seat (28), in opposition to a spring bias and provided by a stack of parallel sliders, the outermost slider being fixed and each of the others displaced along its longitudinal axis, with a wire section of a shape memory alloy between each 2 successive sliders, the final slider coupled to the blocking element at one end.

Description

The invention relates to a controllable Valve, in particular a pneumatic valve in a vehicle seat. Such valves are used to provide and control comfort and safety features used in motor vehicle seats and generally include a valve bore defining Valve seat and a shut-off element that when closed of the valve lies tightly against the valve seat. This will open the valve Shut-off element moves away from the valve seat and thus clears the way that a medium, e.g. Air in a pneumatic valve through which Flow valve bore can.

In controllable valves is used as Actuator in an actuator often uses an electromagnet. This moves the shut-off element between two end positions, namely the sealing position on the valve seat and the valve seat or valve bore Completely releasing position "up" back and forth. The "Closed" position does not allow volume flow through the valve, the "open" position the maximum volume flow. An intermediate position, such as e.g. "30%" volume flow "is with one of an electromagnet controlled valve not realizable because the electromagnet itself only between two mechanical end positions can switch back and forth. That's why with these valves Volume flow control not possible.

Electromagnets also cause the Change between their end positions in the passenger compartment of a motor vehicle as annoying be felt. Furthermore, they cause in the controlling circuit the electrical coils contained in them are voltage peaks or other sometimes undesirable side effects because of their inductive electrical character.

As an alternative to electromagnets electric motors are used in controllable valves. The The disadvantage of using a rotating motor is that some complex mechanics, e.g. Gears and racks, are necessary around the rotary motion of the motor in a linear motion for displacement of the shut-off element. Cause electric motors Moreover like electromagnets disruptive Sounds and vibrations. The use of linear motors, however, offers the advantage of a possible one direct control of the sealing element, however, the cost is one Linear motor for many valve applications, especially in mass production, too high.

The weight of a valve, the one Containing electromagnets or electric motors is because of the weight the coil windings or the armature in the motor or electromagnet high.

There are intermediate positions between "Open" and "Closed" for valves possible by using stepper motors. The weight of these engines is usually even larger compared to other engines. The control Such a motor is only with increased circuitry Effort possible what turn in higher ones costs for the entire valve precipitates.

The control of valves with Piezo ceramics usually involve a complicated and expensive manufacturing process ahead. Piezo elements are also depending on the structure vulnerable against external loads like vibration, shock or Pressure on the valve body. High voltage in the range above 100V is necessary for control, which means the use of piezo elements in many applications is already ruled out for safety reasons. The actuator forces of one Piezo actuators are small, if not large, in terms of volume and weight to be accepted.

From the DE 199 63 499 A1 a valve arrangement is known in which a valve body can be actuated via a shape memory element. The overall length of such an arrangement is, however, relatively large, since a shape memory element has only about 5% of its total length. A design as a proportional valve requires the series connection of several shape memory elements made of different materials and / or geometries.

The DE 197 38 296 A1 discloses a mechanism for generating positioning movements, which also includes a shape memory element. Fast and defined switching behavior and defined switching states of the mechanism are achieved here by means of an additional spring mechanism operated by the shape memory element, and the gradual change in shape of the shape memory element is implemented.

The DE 43 22 731 A1 discloses a valve for regulating fluid flows with an actuator made of electrically heatable, shape-remembering material. In addition to the external heating of the actuator, the fluid flow itself, in cooperation with the actuator, utilizes the temperature behavior of the material to implement a control function. The valve disclosed is complex because of its integrated control function.

The object of the invention is a To propose controllable valve that operates quietly, a controller of the volume flow and also if possible is low in weight, and with which a large adjustment stroke is made possible.

The object is achieved in the case of a valve of the type mentioned at the beginning according to claim 1 as follows: The actuating element contains an actuator which is made of a shape memory alloy det. The actuator is a wire section, which is connected at one end to the shutoff element in terms of drive, directly or indirectly. The actuating element comprises a stack of sliding carriages arranged parallel to one another. A first outer slide carriage is fixed in place, while the other slide carriages are displaceable in the direction of their longitudinal extent. A second outer slide is drivingly connected to the shut-off element. A wire section is arranged between two adjacent sliding carriages, which connects their opposite ends to one another.

An actuator formed from a shape memory alloy changes its geometric shape continuously with increasing intrinsic temperature above a lower limit temperature T _S and thereby causes an actuating stroke. Since the shut-off element is moved by the adjusting element, the actuating stroke of the adjusting element causes a working stroke of the shut-off element. In conventional shape memory alloys, the limit temperature T _{S is} approximately 80 ° C. The maximum shape change of the shape memory alloy is reached at an upper limit temperature T _E. A further increase in temperature no longer causes a change in shape, but rather leads to life-limiting stress for the material. In the direction of its change in shape, the actuating element exerts a force which acts against the force caused by a spring element. The actuator and thus the actuator are resiliently biased by the spring element against the actuating stroke.

Because of the simple construction of the valve and the lack of wire windings or anchors in motors or electromagnets can compare the proposed valve compared to previous valves are designed to be significantly less weight. The construction volume is therefore also very small. The energy intake is also low because the heat capacity of the relatively small Actuators made from shape memory alloy is negligible. The adjustment of the shut-off element is practical noiseless by itself because of a change in shape in shape memory alloy neither when heating still while cooling Sounds caused.

Because the expansion and contraction the shape memory alloy is a continuous process that has any intermediate positions between full contraction and full expansion is arbitrary Degree of valve opening and thus control of the volume flow passing through the valve possible.

In the case of an actuator formed from a wire section, wire diameters of approximately 0.06 mm-0.1 mm have proven successful. One end of the wire section is fixed, for example, to the valve housing and at the other end it is connected directly or indirectly to the shut-off element. A wire section made of a shape memory alloy that is prestressed with a spring element has the property of contracting up to 8% in the longitudinal direction when heated in the range between the limit temperatures T _S and T _E. With a wire diameter of 0.06 mm, a tensile force of approximately 0.7 mN can be generated. A shape memory alloy in the form of a wire also has the advantage that the wire section can be heated very quickly, especially with a small wire diameter. Cooling down by temperature compensation with the surroundings is also possible very quickly. This ensures that the valve has short switching times.

In many cases, this ranges from one individual Wire section generated change in length in the form of the stroke. According to the invention, this increases the actuating stroke achieved that the actuator contains several sliding carriages that in the form of a stack e.g. one above the other are arranged. The sliding carriages are expediently flat and elongated, e.g. in the form of a very flat, elongated cuboid. The longitudinal directions the individual slide are parallel. A first outer, e.g. the top slide is stationary, e.g. fixed to the housing. The remaining sliding carriages are in the direction of their longitudinal extension displaceable. A second outer, e.g. the bottom slide is driven by the shut-off element connected to guide this.

Between two neighboring, so e.g. directly one above the other lying slide is arranged a wire section each. The Each wire section connects one end of a slide with that in the longitudinal direction opposite the slide End of an adjacent sliding carriage and thus represents a mechanical Connection between the slide.

The wire sections and slide are thus connected in series and one above the other in a space-saving manner layered that the individual length changes of the wire sections add approximately to the total actuating stroke of the actuating element.

The heating of the shape memory alloy or the wire section is technically simple and in particular space-saving way due to an electrical current flow in the shape memory alloy accomplished. A controllable current source is provided for this purpose, the electrically conductive to the ends of the actuator or the wire section connected. In a further embodiment, the controllable Valve a sensor to determine the actuating or working stroke of the actuating or shut-off element. So the current position of the actuator or the shut-off element, i.e. the open position of the valve determined and e.g. be further processed in an external control device. A feedback This enables controlled and precisely defined opening positions to the control element between the end positions "closed" and "open" of the valve Control of the volume flow.

In a particularly preferred embodiment contains the lifting device e.g. electrical attached to the valve body Resistance track and an electrically sliding on it conductive Tap. Resistance path and tap thus form in a linear Movement of the tap an electrical linear potentiometer. The tap moves corresponding to the opening or working stroke, is So coupled with this movement. This can be done, for example a driver pin attached to the control element can be reached, that leads the tap on the conductor track. The between tap and Electrical ohmic resistance measured at one end of the resistance path changes so corresponding to the opening or working stroke, for example in the range from 0kΩ to 2kΩ. Determining the position of the shut-off element and thus the degree of opening of the valve can be carried out by a simple electrical resistance measurement.

Often that is generated by the control element Power is not sufficient, but an adjustment stroke is available, the is bigger as for the actuation of the shut-off element is necessary. In a preferred embodiment is therefore a gear between the control element and the shut-off element connected. This can happen when the forces between the actuator and shut-off element are converted by a factor k, the strokes between the actuator and shut-off element by a factor of 1 / k. A rotatably mounted deflection lever is particularly suitable for this, are articulated on the actuating element and shut-off element.

An advantageous embodiment of the Invention results when the shut-off element is an axially displaceable Valve lifter with an axle and a sealing element attached to one axle end, wherein the spring element is a coil spring that is coaxial arranged the axis of the valve lifter is.

For a further description of the invention is based on the exemplary embodiments referred to the drawing. Show it:

1 a valve in a schematic functional representation in the (a) closed and (b) open state,

2 an alternatively designed actuator in the rest (a) and working position (b) in a schematic functional representation,

3 a valve as a schematic diagram in an exploded view.

A controllable valve 2 in 1 in the version as a pneumatic valve, that is to say for controlling, for example, the filling state of an air cushion in a vehicle seat, contains a movable shut-off element 4 , an actuator 6 and a lifting device 8th , The shut-off element 4 consists essentially of an elongated push rod 10 , on one end 12 a sealing plug 14 concentric to the central longitudinal axis 16 the push rod 10 is appropriate. The push rod 10 is in camps 18a and 18b slidably guided so that it can be moved in the axial direction. Camps 18a, b are fixed to the housing 20 of the valve 2 connected.

On the push rod 10 is a flange 22 molded on, which extends the diameter of the push rod radially, so that the flange at the free end 23 the side facing the push rod is in a plane perpendicular to the longitudinal axis 16 the shoulder of the push rod 26 forms. Between the flange 22 and the camp 18b is on the guide rod 10 coaxial to their central longitudinal axis 16 a coil spring 24 placed. The coil spring 24 is supported by one end of the bearing 18b and with their other end on the support surface 26 of the flange 22 from. The distance between the stop shoulder 26 and the camp 18b is less than the axial length of the spring 24 in their unloaded condition. The preload of the installed spring achieved in this way 24 generates sufficient contact pressure that in, in 1a shown, closed state of the valve 2 the sealing plug 14 with sufficient contact pressure on the valve seat 28 is applied. The valve bore 30 is therefore adequately sealed against the flow of air.

A bell crank 32 is rotatable at one end in the valve housing 20 in a camp 34 stored. On the joint 36 is the lever 32 with the push rod 10 connected. At the camp 34 opposite end of the lever 32 this is over the joint 38 with the linkage 39 of the control element 6 connected. At that of the linkage 39 opposite end is the actuator 6 through the attachment 40 with housing 20 firmly connected. The articulation of the shut-off element 4 is through a redirection with a lever 32 mechanically simple in contrast to the conversion of a rotary movement (eg a drive motor) into a longitudinal movement.

The actuator 6 contains as an actuator a wire section made of a shape memory alloy 42 , with the articulation at both ends 39 or the attachment 40 is firmly connected. The wire section ends can be secured by crimping, clamping, etc. The wire section has fastening points at both ends 42 also electrical connections 44a and 44b that have an electrical wire 46 with a power source 48 are connected. In 1a provides the power source 48 no electricity, so the wire section too 42 is not traversed by electricity.

A change in length of the wire section 42 transfers through the lever 32 on a movement of the push rod 10 and thus on the movement of the sealing plug 14 from the valve seat 28 out or into it.

The position sensor 8th contains a with participants tap 50 that stuck with the linkage 39 of the control element 6 connected is. Two resistance tracks 52a and 52b are fixed to the housing 20 connected and lie both parallel to each other and parallel to the direction in which the articulation 39 moves when the wire section 42 its length changes. At two adjacent ends of the resistance tracks 52a, b are connections 54a, b appropriate.

On the driver pin 50 is a shorting bar 56 attached, the sliding on the resistance tracks 52a, b rests and this at the position of the driver pin 50 electrically conductive interconnects. In the direction of measurement 58 can therefore between the connections 54a, b an ohmic resistance R1 can be measured, which is the sum of the partial resistances of the sections of the conductor tracks 52a and 52b between the connecting lines 54a and 54b and the position of the driver pin 50 results. The total resistance measured is therefore proportional to the position of the driver pin 50 , Since this is fixed to the linkage 39 connected, the resistance is also a measure of the length of the wire section 42 , Because the linkage 39 over the lever 32 with the push rod 10 connected, the resistance is also a measure of the position of the push rod 10 and thus a measure of the actuating stroke of the valve 2 ,

In 1b provides the power source 48 a current I ≠ 0. Via the line 46 and the electrical connections 44a, b the current I flows through the wire section made of the shape memory alloy 42 , Due to the current flow in the wire section 42 this heats up. When the limit temperature T _{S is} exceeded, the shape memory alloy begins to change its volume by changing its crystal structure. This leads to a contraction in length of the wire section 42 in its axial direction.

Because the wire section 42 on the attachment 40 firmly with the housing 20 connected, the length contraction of the wire section leads 42 that the linkage 39 the attachment 40 approximates and the joint 38 of the lever 32 emotional. Because of the lever rotation in the joint 34 experiences the push rod 10 about the joint 36 also a shift in the axial direction, in the direction of the arrow 60 , The deflection of the push rod 10 leads to the sealing plug 14 out of the valve seat 28 moves and so the valve bore 30 releases so that air can flow through it.

The movement of the push rod 10 takes place against the resilience of the coil spring 24 , The coil spring 24 is pressed together in the axial direction because it is connected to the push rod 10 the stop shoulder 26 to the camp 18b moved. The bell crank 32 serves to convert force or path between the movement of the linkage 39 of the wire section 42 and the axial displacement of the push rod 10 about 3: 1. That is why it is on the joint 38 attacking, from the contracting wire section 42 caused force on the joint 36 in the triple, on the push rod 10 acting force translated. Because of the movement of the end 63 of the wire section 42 he experiences on this and on the linkage 39 mechanically fixed pins 50 a displacement perpendicular to its longitudinal axis in the direction of the contraction direction of the wire section 42 , The one on the spigot 50 attached shorting bar 56 slides along the coal tracks 52a, b and now bridges them electrically at another position along their length. Between the electrical connections 54a, b therefore a resistance R2> R1 is measured. Because the resistance value is proportional to the position of the end 62 of the wire section 42 and thus proportional to the axial displacement position of the push rod 10 changed, this is a measure of the degree of length contraction of the wire section 42 and for the open position of the valve 2 ,

After switching off the current I in the power source 48 becomes the wire section 42 no further flow of electricity and no further heating. The one in the wire section 42 stored heat is released to the environment and the wire section 42 cools down. The force exerted by the wire section 42 went out and the linkage 39 to the attachment point 40 has moved disappears. That of the preloaded spring 24 The force exerted acts on the shoulder 26 and the push rod 10 will be in the opposite direction of the arrow 60 emotional. The sealing cone 14 slides towards the valve seat 28 back until he got the in 1a shown starting position reached. Via the bellcrank 32 and the linkage 39 becomes the wire section 42 in the axial direction back to its original in 1a shown length stretched. The one at the linkage 39 attached pegs 50 and with it the shorting bar 56 also slide back to their starting position. So that the valve 2 In the rest position, for example, closes securely, is the shut-off element 4 against the valve seat 28 through the coil spring 24 biased. In the case of an electrically controlled valve 2 this means that in the event of a power failure the valve 2 is blocked for security reasons.

As the temperature of the shape memory alloy falls, the force caused by the actuating element in the direction of the actuating stroke decreases. Once the from the actuator 6 generated force less than that of the coil spring 24 force exerted on it forces the control element back into its starting position continuously as the temperature drops. This process can also be continuously controlled by controlling the temperature of the shape memory alloy and can be stopped at any position. As a result, the speed at which the shut-off element is moved both in the opening and in the closing direction is arbitrary. The valve can therefore be opened or closed slowly or quickly.

In the illustrated embodiment of the invention, the shut-off element acts 4 bias de coil spring 24 at the same time as a reset element for the control element 6 , This can reduce the number of components in the valve 2 can be reduced, which in turn contributes to a simpler and less expensive manufacture of the valve.

Do you understand the in 1b shown contraction of length of the wire section 42 as the maximum contraction caused by the current I _E in the wire section 42 generates a temperature T _E , ie a further temperature increase due to a larger current I> I _E does not lead to a further contraction of the wire section 42 , the position shown represents the maximum opening position of the valve 2 By targeted supply of a current 0 ≤ I ≤ I _E from the current source 48 that the wire section 42 heated to any temperature T _S ≤ T ≤ T _E between the limit temperature T _S and the maximum temperature T _E , any intermediate position between the closed ( 1a ) and fully open ( 1b ) Position of the valve 2 can be achieved. The resistance R clearly assigned to each intermediate position, that in the measuring direction 58 is tapped, serves as an input variable for a corresponding, not shown, higher-level control, which controls the current I accordingly, to the desired temperature of the wire section 42 to keep.

That through a single wire section 42 Length changes achievable from a shape memory alloy are often not sufficient. 2 therefore shows an arrangement in which the changes in length of individual wire sections 62a, b add up roughly.

In a fixed framework 64 is a first slide 66a attached. More sliding carriages 66b and c are in camps 68b, c slidably mounted so that they can be moved in their longitudinal direction. At one end of the slide 66a and the opposite end of the slide 66b is a wire section 62a attached from a shape memory alloy. Corresponding is a second wire section 62b also from a shape memory alloy between the sliding carriages 68b and c attached. The sliding carriage 68a-c are electrically conductive and the ends of the wire sections 62a, b electrically connected to the slide. At the connection points 44a, b is an electrical power source 48 via electrical cables 4b connected. The wire sections 62a, b are thus in an electrical series connection with the slide 68a-c , About a feather 70 is the articulation 39 in the direction of the arrow 72 towards the frame 64 biased.

In 2 B a current I ≠ 0 is fed into the arrangement, which covers all wire sections 62a, b flows. Corresponding l the current flow leads through the wire sections 62a, b to warm them up. After the limit temperature T _{S has been} exceeded, the wire sections begin 62a, b with their contraction in length. The contraction in length of the first wire section 62a leads to the sliding carriage 60b in the direction of the arrow 74 relative to the housing 64 attached slide 66a emotional.

Even without changing the length of the wire section 62b this also makes the slide 66c together with the slide 66b in the direction of the arrow 74 postponed, which is why the linkage 39 experiences the same deflection. However, since between the slide 66b and 66c another wire section 62b is switched, which also experiences a contraction in length, the sliding carriage 66c relative to the slide 66b also in the direction of the arrow 74 postponed. The linkage 39 therefore experiences double deflection than that caused by a single wire section 62a or 62b would be caused.

Due to the mechanical series connection of n wire sections and guide carriages, the articulation point is experienced 38 an n-fold deflection. The deflection takes place against the spring tension 70 , A wire section of length L produces a maximum change in length ΔL. By lining up n wire sections of length L, an actuating stroke can be generated in an actuating element that has a total length of approximately L, which is approximately n times ΔL. With an arrangement of length 3 cm, which contains wire sections with a total length of approx. 18 cm, an adjustment stroke of approx. 4 mm can be achieved with a force development of up to 2N tensile force depending on the wire thickness.

Switching off the current I leads accordingly 1 due to the mechanical restoring force of the spring 70 to the arrangement in their in 2a shown rest position returns. The one in the end 76 of the slide 66c attached driver pins 50 with shorting bar 56 can accordingly 1 used to determine the position of the linkage 39 capture.

By stacking more layers of wire section and sliding carriage than the one in 2 shown three sliding carriages and two wire sections, several wire sections can be added, which leads to even greater achievable distance deflections between the mechanical articulation points 40 and 39 the arrangement leads.

An actuator 6 The embodiment just described with several sliding carriages and wire sections is also sold as a prefabricated component by Nanomuscle Inc., Antioch, CA, USA. With this component, approximately 5 full cycles of full contraction and expansion per second are possible.

In 3 is a valve 2 shown that in a housing 20 two independently controllable actuators 6 contains a distribution head 80 drive. The valve contains two shut-off devices 4 and two the actuators 6 assigned displacement transducers 8th , The actuators 6 are corresponding 2 executed as a stack with several wire sections.

The housing 20 is with a lid 82 provided, the pressure-tight with its edge fold 84 in the sealing groove 86 rests. The construction of the actual valve from the valve seat and shut-off element is simple, since no movable but pressure-tight bushings, for example for the shut-off elements, are necessary. The interior of the valve housing is therefore under pressure, depending on the operating mode, continuously or in two-way pressure, and one or more shut-off elements controllably seal a corresponding number of outlet openings in the form of valve bores in order to implement a controllable multi-way valve.

The housing only has the openings 88 through which air can enter or exit the interior of the housing. At the two openings 88 is by means of sealing rings 90 the distributor head 80 attached pressure-tight, for example pressed or glued. Over the neck 92a can air through a channel 94 and the openings 88 flow into or out of the housing interior. The connecting pieces 92b and 92c are across channels 96 with valve seats 98 connected, which is roughly at the center of the circular openings 88 lie.

The shut-off elements 4 contain push rods 10 with flanges 22 and coaxially on the push rods 10 applied feathers 24 , The push rods 10 are sliding in bearings 18a and 18b on. The feather 24 is based on both the flange 22 as well as in stock 18b and clamps the push rod 10 towards the valve seat 98 mechanically. The valve plug that seals the valve seat 100 contains a sealing element 102 that in the recess 104 one on the push rod 10 molded sealing head 106 rests. The sealing head 106 serves as a mechanically stable receiving element. This is the sealing element 102 Exchangeable for maintenance purposes, for example. The sealing element 102 lies on the valve seat 98 sealing in the closed position of the valve. On a molded widening 108 the push rod 10 is the joint 36 attached into which the lever 32 intervenes.

A lever has proven to be favorable in practice 32 with a gear ratio of the actuating stroke to the working stroke of approximately 3: 1. The actuator 6 generated force is thereby on the shut-off element 4 about tripled.

The one on the slide 66c attached linkage 39 of the control element 6 also grabs the lever 32 on. On the slide plate 66c is the cone 50 molded onto the shorting bar 56 parallel to the longitudinal axis of the push rod 10 on the resistance tracks 52a, b moves the stationary on a fixed to the housing 20 connected base plate 114 are attached. The base plate 114 can also be an electrical circuit board, for example. The electrically conductive shorting bar 56 is on a guide element 110 attached that together with this in a housing 112 slides in and is mechanically guided through it.

2

Valve

4

shut-off

6

actuator

8th

Hubaufnehmer

10

pushrod

12

front

14

sealing plug

16

central longitudinal axis

18a, b

camp

20

casing

22

flange

23

free end

24

coil spring

26

stop shoulder

28

valve seat

30

valve bore

32

Umlenkhebel

34

camp

36

joint

38

joint

39

linkage

40

attachment

42

wire section

44a, b

connection

46

management

48

power source

50

driver pin

52a, b

resistance path

54a, b

connection

56

Shorting bar

58

measuring direction

60

arrow

62a, b, c

wire section

63

The End

64

frame

66a, b, c

Sliding carriage

68b, c

camp

70

feather

72

arrow

74

arrow

76

The End

80

distribution head

82

cover

84

edge fold

86

sealing groove

88

opening

90

seal

92a, b, c

Support

94

channel

96

channel

98

valve seat

100

valve plug

102

sealing element

104

recess

106

sealing head

108

widening

110

guide element

112

casing

Claims (8)

Controllable valve with one of an actuator against the action of a spring element movable and with a valve seat cooperating shut-off element, the actuator being one of a Shape memory alloy formed actuator contains, wherein the actuator is a wire section with its one End is directly or indirectly connected to the shut-off element, marked by following configuration: - The control element comprises a stack of sliding carriages arranged parallel to each other, - a first outer slide is fixed while the other sliding carriages are displaceable in the direction of their longitudinal extent are, - on second outer slide is driving with connected to the shut-off element, - between two neighboring ones Sliding carriage is arranged a wire section, the opposing Connects ends together. Valve according to claim 1, characterized in that the actuator is connected to an electrical power source. Valve according to one of the preceding claims, characterized characterized that a transducer to determine a stroke the actuating element and / or a working stroke of the shut-off element is. Valve according to claim 3, characterized in that the transducer has a fixed resistance track and a sliding track containing electrically conductive tap, the with the actuating element or the shut-off element in motion is. Controllable valve according to one of the preceding Expectations, characterized in that between the actuating element and the shut-off element a transmission is switched. Valve according to claim 5, characterized in that the transmission is a rotatably mounted lever on which the actuating element and the shut-off element are articulated, the lever arm of the shut-off element is smaller than the lever arm of the control element. Valve according to one of the preceding claims, characterized characterized in that the shut-off element is an axially displaceable, valve tappet carrying a sealing element at one end. Valve according to claim 7, characterized by a the valve lifter coaxial comprehensive coil spring.