DE29611808U1 - Valve - Google Patents

Description

*
* * »·· lens • ·. · ■■· ·
: ::··..: : .* ·· ·· 1996 *.· .. ·· · 17 495 - G 19 . June

Festo KG, 73734 Esslingen

Valve

The invention relates to a valve, with a closure body arranged in a valve housing, which can be switched between two switching positions, in each of which it rests against a support section fixed to the housing, wherein the closure body is provided on an elongated carrier, which is mounted on a housing-side bearing point via a suspension section arranged at a longitudinal distance from the closure body and can be deflected transversely to its longitudinal direction in order to switch the closure body, with a spring device which acts on the closure body and pre-tensions it in at least one of its switching positions and with an actuating device for deflecting the carrier for the purpose of switching the closure body.

A valve of this type is described, for example, in DE 36 08 Al. The valve described there is designed as a piezo valve and has a carrier clamped on one side to a bearing point on the housing side, which carries the closure body at the free end. A spring device arranged on the side preloads the closure body into a first switching position in which it rests on a

A piezo device is provided as the actuating device, when activated the carrier is deflected by bending into a second switching position, in which it rests against a second support section also formed by a valve seat. If the piezo device is deactivated, the spring device causes the closure body to automatically switch back to the starting position.

The known valve is already relatively well suited to miniaturization. However, a disadvantage is that a considerable amount of electrical energy is required to switch the valve and in particular to hold the closure body in the switching position deflected against the spring force.

It is therefore the object of the present invention to create a valve suitable for miniaturization in which little energy is required for actuation and for maintaining the desired switching position.

To solve this problem, it is provided that the carrier has two suspension parts which are located at a distance from both sides of the closure body in relation to the longitudinal direction of the carrier and via which the carrier is suspended from two bearing points on the housing side which are spaced apart from one another transversely to the switching direction of the closure body, that at least one length section of the carrier is formed by the spring device, and that the distance between the housing-side bearing points is selected such that the carrier in the

In both switching positions of the locking body, it assumes a curved or bent shape with respect to the connecting line between the bearing points in the switching direction towards the associated support section, which is in each case stabilized by the spring device.

This creates a valve that is particularly suitable for small sizes because its energy consumption is low. The valve has a bistable switching mechanism, whereby a single spring device is sufficient to stabilize the two switching positions. The carrier is designed entirely or partially as a spring device, whereby a spring-elastic preload is achieved in both possible switching positions by a correspondingly small distance between the bearing points on the housing. In the respective switching position, the carrier has a shape that is laterally curved or bent in relation to the imaginary connecting line between the bearing points, whereby the closure body is pressed against the support section. During the switching movement, the carrier passes through a kind of dead center due to deformation, so that with the appropriate design a kind of snapping process can take place. In all of this, the energy required to switch the closure body is relatively low.

Advantageous further developments of the invention are set out in the subclaims.

· il

In principle, there are alternative options to design the support either as a spring device in its entirety or only in part.

If only part of the carrier is formed by the spring device, a compression spring device is expediently provided as the spring device, which is inserted into the longitudinal course of the carrier in such a way that its main spring direction runs in the longitudinal direction of the carrier. It is particularly advantageous here if the spring device is located in the longitudinal section of the carrier located on one side of the closure body and in particular forms this one longitudinal section as a whole, whereby the longitudinal section located on the opposite side of the closure body can be a particularly rigid carrier section that is pivotally suspended at the bearing point. In order to switch the closure body, a short, pulse-like lateral shock can be exerted on the carrier or the closure body by the actuating device, which ensures that the carrier is moved past the dead center into the other switching position. The shock causes an acceleration of the carrier, which can then overcome the spring force and any media pressure that may be present due to its mass inertia. As soon as the dead center is exceeded, the spring device itself acts as a loading device to move the valve body completely into the other switching position.

The actuating device can have a tappet arrangement, in particular two actuators each with a

an actuating tappet that can act on the valve body in one direction or the other. The tappet stroke can be significantly less than the switching path of the closure body if the actuating speed of the tappet is correspondingly high. This can be achieved, for example, by using magnetic coils with overexcitation or piezo translators. The energy supplied per switching process is essential, which can be calculated in particular from the mass and the geometric data of the carrier and the closure body, from the preload force of the spring device and its spring characteristic curve and the media pressure. This energy is relatively low here.

In the case of a carrier designed as a spring device in its entirety, it is expedient to design the carrier as a leaf spring-like, bending spring arrangement that is flexible transversely to the longitudinal direction. Here, it can be provided that the bending spring arrangement has a linear extension in the neutral position and runs practically along the imaginary connecting line between the bearing points. By reducing the distance between the bearing points using a suitable actuating device, the bending spring arrangement can be curved out laterally into a first switching position. To switch over, the holding force acting on the carrier at the movable bearing point only has to be removed briefly, so that the carrier including the closure body is bent back in the direction of the neutral position, swinging beyond this neutral position that marks a dead center. By immediately applying the aforementioned holding force again,

·

·

the locking body can be completely moved into the other switching position and held there.

In this case, the axial preload of an elastically bent support is effectively removed for the period of time that the support needs to reach the neutral position due to its springback. Overcoming the neutral position can in turn be achieved with the help of the kinetic energy of the support and the closure body. In this case, it is sufficient if the actuating device has only one actuator in the form of a suitable adjusting device, which is either controlled accordingly or is suitably tuned due to its natural frequency.

The invention is explained in more detail below with reference to the accompanying drawing, in which: .

Figure 1 shows a first design of the valve according to the invention with a carrier only partially formed by a spring device in a schematic longitudinal section,

Figure 2 shows a further design of the valve according to the invention with a carrier designed entirely as a spring device, again in a schematic longitudinal sectional view, but only showing a section of the valve.

Both valves shown have a valve housing 1 with a valve chamber 2 inside. The valves are designed as 3/2-way valves and have three fluid channels 3, 4, 5, which open out on the one hand on the outer surface of the valve housing 1 and on the other hand into the valve chamber 2.

One fluid channel 3 is a feed channel. It is normally connected to a pressure medium source, in particular a pneumatic one. The opening 6 of this feed channel, which is assigned to the valve chamber 2, is surrounded by a first valve seat 7, which can be formed, for example, by a collar-like annular housing projection.

Another fluid channel 4 is a vent channel. A silencer can be connected to it, for example. An opening 8 assigned to the valve chamber 2 is located at a distance from the opening 6 of the fluid channel 3. It is also surrounded by an annular valve seat 9. The two valve seats 7, 9 are located on opposite walls of the valve chamber 2.

The third fluid channel 5 is a working channel. A consumer to be supplied with the fluid pressure medium can be connected to it. Its opening 12 assigned to the valve chamber 2 is located away from the other openings 6, 8.

A movable closure body 13 is arranged in the valve chamber 2. It has, for example, a plate-like or pill-like shape. In both figures, the closure body 13 is shown in solid lines in a first switching position

14, in which it rests on the valve seat 9 of the fluid channel 4 and closes the associated opening 8 in a fluid-tight manner. The valve seat 9 forms a support section for the closure body 13.

With the aid of an actuating device 16, 16', the closure body 13 can be switched by moving it from the first switching position 14 into a second switching position 15, indicated in the figures by dash-dotted lines. In the second switching position 15, it rests against the other valve seat 7, which also forms a support section 7', and closes the orifice 6 of the fluid channel 3 associated with it and which was open until then in a fluid-tight manner. At the same time, the closure body 13 is lifted off the other valve seat 9, so that the orifice 8 of the fluid channel 4 is exposed.

The switching direction of the closure body 13 during the transition between the two switching positions 14, 15 is indicated by the double arrow 17. In the valve design shown, in the first switching position there is a fluid connection between the feed channel 3 and the working channel 5 via the valve chamber 2. At the same time, the vent channel 4 is blocked. In the second switching position, the feed channel 3 is blocked, while at the same time the working channel 5 communicates with the vent channel 4 via the valve chamber 2, so that the consumer is vented.

The closure body 13 is provided on an elongated carrier 18, which is also located in the valve chamber.2. This carrier 18 has on its two opposite

At each of the narrow ends, the valve has a suspension section 21, 22 with which it is suspended or supported on a housing-side bearing point 23, 24. The arrangement is such that an imaginary connecting line 25, indicated in the figures by dash-dot lines, runs between the two bearing points 23, 24 transversely and in particular at least essentially at right angles to the switching direction 17. According to the example, the bearing points 23, 24 are assigned to opposite walls 26 of the valve chamber 22, which extend transversely to the other walls 29 which are also opposite one another and have the openings 6, 8.

The closure body 13 is arranged between the two suspension parts 21, 22 at a longitudinal distance measured in the longitudinal direction 20. As a result, there is a support section 27, 28 on both sides of the closure body 13, which establishes the connection between the closure body 13 and the suspension part 21, 22 or the relevant bearing point 23, 24.

The closure body 13 can, as shown in Figure 1, be inserted into the longitudinal course 20 of the carrier 18, so that it practically itself forms a component of the carrier. However, the variant shown in Figure 2 is also possible, for example, in which the carrier 18 is a continuous extruded body that runs between the two suspension parts 21, 22 and carries the closure body 13. Here it is expedient to provide a multi-part closure body 13 that has two closure body parts that are located on the two long sides of the carrier 18 facing a respective valve seat 7, 9.

It is advantageous if the closure body 13 is arranged at least approximately centrally between the suspension parts 21, 22.

As can be clearly seen from the figures, the distance measured in the direction of the connecting line 25 between the two bearing points 23, 24 is selected so that the carrier in both switching positions 14, 15 of the locking body 13 takes on a shape in which it is curved or bent out of the connecting line 25 laterally in the switching direction 17. Whether it is a bend or a bulge depends essentially on the design of the carrier 18. In the case of Figure 2, there is more of an arched bulge, while in the case of Figure 1 it is more of a buckling.

The respective curved or bent shape is stabilized by a spring device 32, 32'. This spring device 32, 32 ^' advantageously takes on its stabilizing task in both switching positions 14, 15, whereby it causes the closure body 13 to be pressed against the respectively assigned support section 7', 9 ¹ , which is formed, for example, by a valve seat 7, 9. This is not a spring device 32, 32' provided in addition to the carrier 18, but rather at least a length section of the carrier 18 itself is formed by the spring device 32. A small number of components is the result.

In the embodiment shown in Figure 1, only a certain part of the carrier 18, extending in the longitudinal direction 20, is formed by the spring device 32. This is preferably the one carrier section 28 that extends between the closure body 13 and the one suspension part 22. The spring device 32 is preferably designed here as a compression spring device 33, which is designed in the manner of a helical spring device and which engages at one end on the closure body 13 and at the other end on the bearing point 24. In this way, its main spring device 34 coincides with the longitudinal direction of the carrier 18.

The other support section 27 arranged opposite is, for example, rigid in itself, whereby there is also preferably a rigid connection between the support section 27 and the closure body 13. However, with its opposite end, which forms the suspension section 21, the support section 27 is pivotally mounted on the associated bearing point 23, so that the support section 27 can pivot in a plane that is spanned by the two mouths 6, 8 and the bearing point 23.

The distance between the two bearing points 23, 24 is constant and remains unchanged during operation of the valve.

In the two switching positions 14, 15, the spring device 32 acts with a spring force F on the closure body 13, wherein the direction of the force runs at an acute angle to the connecting line 25. This results in a resulting

Closing force that presses the closure body 13 against the associated valve seat 7, 9.

To switch between the switching positions 14, 15, the actuating device 16 is briefly actuated. In the exemplary embodiment, this comprises a tappet arrangement with two tappets 35, 36, which can act on the carrier 18 or preferably on the closure body 13 at high speed in the desired switching direction, each via an actuator 37.

For example, the tappets 35, 36 are arranged in such a way that their actuating end 42 is opposite the closing surface 38, 38' of the closure body 13, which in the respective switching position faces the associated valve seat 7, 9, with as little distance as possible. For this purpose, a respective tappet 35, 36 can extend through the housing 1 and the associated mouth 6, as shown. By actuating the actuator 37, which is preferably arranged on the outside of the valve housing 1, the relevant tappet 35, 36 is displaced against the closure body 13 - a displaced position is indicated in Figure 1 by dash-dotted lines at 39 - whereby the acted-up closure body 13 is lifted off the associated support section 7, 9 and accelerated in the switching direction 17 towards the other support section. In this case, the compression spring device 33, which is preferably articulated on the closure body 13 and on the bearing point 24, is compressed while reducing its overall length, with the minimum length dimensions being set when the carrier 18 deflected in this way reaches a dead point at which it is on the connecting line

• ·· ♦·· »j * , tt

25. However, this is an extremely unstable equilibrium position. In practice, the situation is that the locking body 13 accelerated by the tappet 35, 36 swings over the dead center due to the kinetic energy or momentum received and is then immediately pushed by the correspondingly deflected compression spring device 33 in the direction of the desired other switching position. It is therefore not necessary for the stroke of the relevant tappet 35, 36 to correspond to the entire switching path of the locking body 13; in some circumstances it can even be less than the path to the connecting line 25. The only requirement is that the locking body 13 receives sufficient kinetic energy. In this context, the locking body 13 is preferably designed in such a way that it acts as an inertia body, the inertial mass of which supports the process. Alternatively, a separate inertia body could also be provided on the carrier 18.

The actuators 3 7 can, for example, be magnetic coils that act on a movable armature that is connected to or forms the relevant plunger 35, 3 6. However, other suitable actuators could also be used.

In the embodiment according to Figure 2, the carrier 18 is designed entirely as a spring device 32'. This is, for example, a bending spring device 43 designed in the manner of a leaf spring, which is flexible transversely to the longitudinal direction 20. The entire length of the carrier 18 is taken up by this bending spring device 43.

While one bearing point 24 is arranged stationary on the valve housing 1, the other bearing device 24, which is also supported on the valve housing 1, is movable relative to the valve housing 1 as required. It is located on a rod-like or tappet-like actuator 44 of an actuator 37' of the actuating device 16' and can be displaced by displacing the actuator 44 transversely to the switching direction 17 in the longitudinal direction of the connecting line 25. This allows the distance between the bearing points 23, 24 to be varied.

In the two switching positions 14, 15 there is a minimal distance between the bearing points 23, 24. Since the length of the carrier 18 is greater than this distance, the carrier takes on the curved shape shown in Figure 2.

In order to switch the closure body 13, the movable bearing point 24 is moved away from the other bearing point 24 by actuating the actuator 37' in order to increase the distance. The suspension section 22 attached to the movable bearing point 24 is pulled along so that the curvature of the carrier 18 is reduced, whereby the closure body 13 lifts off the support section 9. A corresponding intermediate position of the carrier 18 is indicated in dash-dot lines at 45.

The suspension section 22 can be pulled back until the distance between the bearing points 23, 24 corresponds to the length of the support 18 in the extended linear state. Here the support 18 assumes the neutral position indicated by the dot-dash line at 46.

position in which it runs along the connecting line 25. The position assumed by the movable bearing point 24 is indicated at 47.

The carrier 18 is preferably designed so that the neutral position 46 is the position it assumes in the unloaded state. In order to reach the two switching positions 14, 15, an actuating force directed towards the opposite bearing point 23 must be exerted on the associated suspension section 22 via the actuator 37' so that the distance between the bearing points 23, 24 is reduced and the carrier 18 is forced into the curved shape. However, this has the advantage that no switching force is required to initiate the switching process. It is sufficient to remove the actuating or holding force of the actuator 37 ^! so that the closure body 13 moves in the switching direction 17 solely due to the inherent elasticity of the carrier 18. Here, again, it is advantageous that, due to the existing kinetic energy, the closure body 13 does not stop when the neutral position 46 is reached, but swings beyond the linear shape of the carrier 18 or the neutral position. If the actuator 37' is now immediately displaced again in the sense of a reduction in the distance between the bearing points 23, 24, the closure body 13 is forced into the other switching position.

To switch over, the axial preload of the elastically curved support is removed for exactly the time it needs to reach the neutral position. The advantage here is that only one actuator 37' is required,

for example an electromagnet or a particularly miniaturized linear drive.

It would also be conceivable to design the carrier 18 at least partially as a spring device that is made up of different types of springs. For example, in the design according to Figure 1, one could imagine providing a bending spring arrangement similar to the type described in Figure 2 instead of the rigid carrier section.

In all embodiments, a valve with a bistable switching mechanism is present, whereby, depending on the design, very low switching forces and/or very low holding forces are required.

Claims (15)

G 17 495 - lens 19 June 1996 Festo KG, 73734 Esslincren Valve Claims 1. Valve, with a closure body (13) arranged in a valve housing (1) which can be switched between two switching positions (14, 15), in each of which it rests against a support section (7 ¹ , 9 ') fixed to the housing, the closure body (13) being provided on an elongate carrier (18) which is mounted on a housing-side bearing point (23) via a suspension section (21) arranged at a longitudinal distance from the closure body (13) and can be deflected transversely to its longitudinal direction (20) in order to switch the closure body (13), with a spring device (32, 32 ') which acts on the closure body (13) and prestresses it in at least one of its switching positions (14, 15) and with an actuating device (16, 16 ') for deflecting the carrier (18) for the purpose of switching the closure body (13), characterized in that the carrier (18) has two suspension parts (21, 22) which are located at a distance from both sides of the closure body (13) with respect to the longitudinal direction (20) of the carrier (18) and via which the Carrier (18) is suspended from two housing-side bearing points (23, 24) which are spaced apart and transverse to the switching direction (17) of the closure body (13), that at least one length section of the carrier (18) is formed by the spring device (32, 32'), and that the distance between the housing-side bearing points (23, 24) is selected such that the carrier (18) in the two switching positions (14, 15) of the closure body (13) assumes a curved or bent shape with respect to the connecting line (25) between the bearing points (23, 24) in the switching direction (17) towards the associated support section (7 ^!, 9'), which is in each case stabilized by the spring device (32, 32'). 2. Valve according to claim 1, characterized in that only a part of the carrier (18) is formed by the spring device (32). 3. Valve according to claim 2, characterized in that the spring device (32) is located in the longitudinal section of the carrier (18) located on one side of the closure body (13). 4. Valve according to claim 2 or 3, characterized in that the spring device (32) is a compression spring device (33) which is arranged such that its main spring direction (34) runs in the longitudinal direction (20) of the carrier (18). 5. Valve according to claim 4, characterized in that the compression spring device (33) is a helical spring device. 6. Valve according to one of claims 3 to 5, characterized in that the longitudinal section of the carrier (18) located on the side of the closure body (13) opposite the spring device (32) is a rigid carrier section (27) pivotally connected to the associated bearing point (23). 7. Valve according to one of claims 2 to 6, characterized in that the distance between the bearing points (23, 24) is unchangeable. 8. Valve according to claim 1, characterized in that the carrier (18) is formed entirely by a spring device (32 ^! ). 9. Valve according to claim 8, characterized in that the carrier (18) is partially formed by a compression spring device (33) which is arranged such that its main spring direction (34) runs in the longitudinal direction (20) of the carrier (18). 10. Valve according to claim 8 or 9, characterized in that the carrier is at least partially formed by a leaf spring-like, bending spring device (43) which is flexible transversely to the longitudinal direction (20) of the carrier (18). 11. Valve according to one of claims 8 to 10, characterized in that the carrier is formed entirely by a leaf spring-like bending spring device (43). 12. Valve according to one of claims 1 to 11, characterized in that an inertia body, which is formed in particular by the closure body (13) and supports the switching process, is arranged on the carrier (18). 13. Valve according to one of claims 1 to 12, characterized in that the actuating device (16) has a tappet arrangement (35, 36) which can act on the closure body (13) or the carrier (18) in particular in a pulse-like manner for switching. 14. Valve according to one of claims 1 to 12, characterized in that the actuating device (16 ^! ) has an actuator (37') fixed to the housing, which has an actuator (44) having one bearing point (24) which can be displaced transversely to the switching direction (17) in order to change the distance between the two bearing points (23, 24).- 15. Valve according to one of claims 1 to 14, characterized in that at least one and preferably both support parts (7', 9') are formed by a valve seat (7, 9) associated with a fluid channel (3, 4).