Pressure control valve

The invention refers to a valve which can be operated by a solenoid. The armature of the solenoid acts here on a control element. This is axially shifted here in such a way that the gap width of a gap provided in a valve bush changes. The control element consists of a control pin and a control part which manufactured separately from this and attached to the control pin, the control part interacting with the gap.

This application has a priority of German no. 10 2009 035 902.8 filed Aug. 3, 2009, hereby incorporated by reference.

The invention refers to a valve, in particular a pressure control valve, operated by a solenoid, wherein the armature of the solenoid acts on a control element of the valve and shifts it in such a way, in particular axially, that the gap width of a gap provided in or on a valve element, such as for example a valve plate or valve bush, changes, and the gap closes or opens, respectively.

BACKGROUND OF THE INVENTION

In pressure control valves operated by solenoids the power of the solenoid changes the gap between the control element and the valve seat arranged in the valve bush or the valve element, and thus the hydraulic pressure at the work connection is controlled. The gap is limited, on the one hand, by the valve seat and, on the other hand, by the terminating surface provided on the control element. As the position of the control element, and therefore the terminating surface, can change, also the distance (gap width) of the surfaces limiting the gap changes. The control element consists here of a control pin produced from metal, usually turned, to which a suitable seal surface is attached in one piece interacting with the valve seat. The solenoid consists of a coil which can be charged with electricity encircling an armature space. In the armature space an armature acting on the control element is supported moving on bearings the axial position of which can change by the electrifying of the coil. Because of this axial position change the gap width on the control element changes, of course, also opening or closing of the valve is possible.

Producing the control element by turning and therefore removing material is expensive.

SHORT SUMMARY OF THE INVENTION

Therefore it is an object of the invention to suggest a valve which can be produced more economically.

This problem according to the invention is solved by a valve as described in the beginning, where it is suggested that the control element is formed by a control pin and a control part produced separately from it and attached to the control pin, and the control part interacts with the gap.

The invention here intentionally suggests a multi-piece construction of the control element as the effort for machining for in particular the control part can be reduced clearly by that. Now it is possible to optimize the control part for the respective case of application, for example depending on the operating pressure, medium which has to be controlled, and so on, and to use always the same control pin for the movement of the control part. Therefore the batch size of the standardized control pins which are connected with accordingly optimized control parts remain therefore very large. The gap is limited, on the one hand, by the valve seat, and, on the other hand, by the terminating surface arranged on the control part. The gap width is defined, for example, via the shortest distance between the valve seat and the terminating surface. The seal surface is here a part of the terminating surface.

Control part and control pin are connected here to each other in a suitable way, for the pairing of their materials very different variations are possible here. Gluing may be provided here, however, it is also possible to use, according to the invention, jamming, welding or another positive or non-positive connections. As deliberately also differing materials of control part and control pin are comprised by the invention, the more economic production of a valve according to the invention comes with a higher valve dynamic, namely if for the control part a lighter way of construction is realized, for example with a material with less thickness. Because of the here possible module principle a pressure control valve according to the invention can be optimized here by using the same control pin also with reference to its valve dynamic by varying the respective control part to the respective application.

Here the saved material and mass, respectively, is not only based on an accordingly differing selection of materials for control pin and control part, basically the invention also comprises applications where control pin and control part are made from the same material, wherein, however, for example the control part is produced from a plane material by a punch-bending or punch-sinking process, which can be realized very economically in a mass production, and then, because of the low wall thickness of the control part, contributes to a suitable mass production; the identity of materials, however, allows, for example, welding of the control part on the control pin!

In the application the term valve plate or valve bush is described as an example of design of the valve element. As far as a characteristic has only been used for the characteristic of the valve bush or the valve plate, or is defined here, this does not restrict the invention in this area. Instead of the term valve bush or valve plate, generally also the term valve element can be used.

In the same way the invention can also be applied to valves, in particular pressure control valves where the armature acts directly or indirectly on the control element. If the arrangement is indirect, for example, a transition element is provided between the armature and the control element which is, if necessary, even cantilevered, in the same way as also the control element. Resetting or a stopper is reached, for example, by a suitable pullback spring or the like. Of course, it is also provided according to the invention that the control element, in particular the control pin, is connected fixedly (and thus for example directly) with the armature. Both above mentioned modifications are part of the invention.

With reference to the design of the control part the invention can also be employed very variably. It is possible that the control part is designed like a disc, plate, cone, funnel or tapered, the possibilities of realization of the control part being not restricted to these modifications. Thus it is, for example, possible that also ring disc-like control parts and so on can be used. Of course, the suitable choice of the control part has to be adjusted to the case of application and the design of the valve bush, in particular the valve seat so that the different types of control parts relate to the respective application cases.

It has been found that funnel-like, cone-like or tapered control parts have advantages, in particular with fast acting valves or fast controlling pressure control valves, as they have, besides the higher valve dynamic caused by the mass reduction, also a higher stability against pressure vibrations because of the cone-like, tapered or funnel-like design. Therefore, then the control part has on the back an accessible chamber, as it is also shown in the drawings (see reference number 22).

The tapered design has furthermore a design with good flow characteristics which diverts the medium to be controlled in a suitable way, following the surface of the tapering. By means of such a design even with high pressure a flow as laminar as possible can be kept, and flow losses are accordingly avoided.

In a preferred embodiment of the invention the control part is thin-walled. The thickness of the wall limiting the control part is here clearly smaller than the diameter of the control pin or its radius. Besides a relative definition of the term “thin-walled” with reference to other dimensions of the valve according to the invention, the thin-walled quality, however, can also be described as an example (and therefore not restricting) with a wall thickness of less than 2 mm, in particular less than 1 mm, preferably less than 5/10 mm or 8/10 mm. The correct wall thickness results in particular from the application case of the invention. It is clear that an accordingly smaller material thickness contributes also to a reduced mass and therefore to a corresponding valve dynamic. It has to be taken into consideration here that the thin-walled design of the control part can be employed with disc-like, ring disc plate or even cone-like or tapered designed control parts. This modification according to the invention is here not only restricted to the particular choice of material of the control part, the control part can be realized from metal, for example light metal, aluminum, or even non magnetizable or unmagnetizable materials or steels.

Besides a thin-walled design of the control part the invention also includes, however, modifications where a cone-like or tapered control part is formed, for example, of solid material.

In a preferred modification of the invention the control part is characterized by a chamber or the rather thin-walled terminating wall of the control part encircles a chamber which is accessible from the backside, tilted away from the tip of the cone. Here usually the control part is connected with its cone or tapered tip with the control pin in such a way that the control pin penetrates the control part, and actually the design of the control part is truncated in this area which, however, can be seen, according to the invention, as described as cone-like, funnel-like or tapered. Because of the cone-like or tapered design the (exterior) terminating wall of the control part extends at an acute angle to the longitudinal axis of the control pin, and thus a chamber is formed which is also filled by the medium which has to be controlled or adjusted.

In a preferred embodiment it is provided that in the connecting area of control part and control pin on the control pin a circumferential groove or surface recess is provided filled by the material of the control part. By including a suitable circumferential groove or surface recess in the control pin during connecting the control part on the control pin material is pressed in and thus a positive locking is performed. The circumferential groove or the surface recess is here not only filled by the metallic material of the control part, the control part can also consist, for example, of synthetic material, and can be arranged in a plastic injection process on the control pin, wherein then the (still liquid) plastic fills the circumferential groove or a suitable surface recess.

The basically two-piece construction of the control element with control pin and control part makes it possible that control pin and control part can also be of different materials, however, the modification where both are produced from the same material is also part of the invention (e.g. metal with metal, or synthetic material with synthetic material). Control part and control pin, respectively, can therefore be formed by plastic, fiber reinforced plastic, high temperature resistant plastic, highly resistant plastic, or metal, in particular non-magnetic or low-magnetic material, such as suitable steels and so on. Furthermore the control part is, alternatively for example, formed also from a metal film or a thin-walled metal part, alternatively it can also consist of ceramic.

Exactly the employment of new high temperature polymers with a melting point above 380° C. and a glass transition temperature of at least 150° C. makes it possible to provide economically high temperature resistant and light control parts, and thus also to handle reliably even more extreme application ranges of valves according to the invention, in particular pressure control valves.

In a preferred embodiment of the invention it is provided that the control pin is guided or supported on bearings in a core, and the core has a raised part facing the control part which immerses at least during an axial return movement of the control pin at least partly in the chamber. In this example, as it is also shown in the drawing (seeFIGS. 2 and 3) an additional improvement against pressure vibrations has been observed, as this magnet geometric (in particular if in every operating position of the control part projects in the chamber) results in an additional absorption quality. The result of the immersion of the raised part in the chamber is that the volume of the medium within the chamber is separated (almost) completely from the other volume flow, and a corresponding medium wave penetrates no more here or only very damped. Therefore, the result is that the cone-like, funnel-like or tampered, if necessary also, thin-walled control part is “stiffened”. Thus a high stability against the vibrations of the medium is combined with a high valve dynamic because of the low weight of the control part.

In the same way, however, the invention also comprises a solution where a one-piece modification of the control element is produced, for example, from plastic or metal. Material for the one-piece embodiment of the control element can be here all materials described in this application, that is, for example, plastic, fiber reinforced plastic, high temperature resistant plastic, highly resistant plastic, metal, in particular non-magnetic or low-magnetic metal, thin-walled metal, sheet metal or film, and ceramic, respectively. Generally here, for example, suitable steels are used, however, it is also possible to employ, for example, copper, aluminum or other metals according to the invention. The choice of the above mentioned metals relates here to all application cases of this invention and application, respectively.

It is also possible here to produce a one-piece control element of metal materials, for example by turning or with a suitable process, such as for example drawing and folding. Basically, it is also possible, if the materials of control element and control part are the same, that the two separately manufactured elements are, for example welded, to each other later, and thus are in one-piece according to the definition (because of the identical materials and the identical connection of the materials), but nevertheless the advantage according to the invention has been reached in the production.

DETAILED DESCRIPTION OF THE PREFERRED DESIGN

In the figures identical or corresponding elements each are indicated by the same reference numbers, and therefore are, as far as not advisable, not described anew.

The valve1according to the invention is shown schematically in different modifications in the figures. The shown valve1is operated and controlled, respectively, by a solenoid100which is also part of the invention. Usually, a solenoid comprises an armature supported moving on bearings in the armature compartment acting on the control pin20.The armature compartment is surrounded by a coil which can be electrified which generates a suitable magnetic field. According to the generated magnetic field the armature shifts axially so that also the control pin20is shifted axially.

The control pin20is here a part of the control element2.

The solenoid would be linked above the valve1, the control pin20is supported or guided in the core30in a suitable way.

The valve1shown in the drawing is designed in particular as pressure control valve. The valve1here comprises a valve bush15, in which a valve seat11is provided. In the example shown here the valve seat11is realized by a carrier18with centric penetration opening17and a guide cage16connected underneath.

The double arrow27indicates axial adjusting of the control element2. Because of the tapered design of the control part21it becomes clear that the control part21releases more or less the opening17provided in the valve seat11depending on the axial position (27) of the control part, that means it enlarges or reduces the gap10.

In the modifications shownFIGS. 1,2and3the axial position of the control part21is thus that the gap10is closed almost completely, that means the control part21sits almost in the valve seat11. The result is here a choking of the medium pressure and thus a suitable reduction of the pressure at the work connection14. The medium, which may be, for example, liquid or gas, is connected to the pressure connection13.

An essential part of the invention is the fact that the control element2is in two pieces, that means it has a control pin20and a control part21which is manufactured separately and, if necessary, consists of identical or different materials. For an exact, but also mechanically stable, connection on the control pin20on a suitable spot a circumferential groove24is provided in which material of the control part21immerses, according to the connecting process of control part21to control pin20. By means of that it is possible to realize a positive locking between the control part21and the control pin20which can be stressed mechanically.

As shown in the drawings, the control part21is not provided on the end of the control pin20, but there is still a certain projecting end26below the connecting area28, which comprises, of course, the circumferential groove24. By means of this projecting end26other control pieces12of the valve are selected for different purposes. Below the carrier18the guide cage16is linked serving for guiding the projecting end26of the control pin. In the embodiment shown here, for example, a ball19is held in a cage in such a way that by operating the control pin20or the projecting end26it can only be shifted downward, and then releases a suitable passage. The ball19is here loose, that means separated from the control pin20.

The control part21has a seal surface25. This seal surface25is part of the exterior terminating surface or the surface area of the tapered or cone-like control part21. A certain area of the terminating wall23, which is rather thin-walled, is supported in the completely closed condition on the valve as seal surface25on the valve seat11, and seals the gap10completely. The material thickness of the thin-walled terminating wall23is here less than 1.5 mm, preferably less than 1.0 mm, in particular less than 800 μm. Depending on the diameter of the control pin the wall thickness is less than 50%, preferably less than 35%, in particular less than 30%.

The embodiment for the control part21shown inFIG. 1consists of a metal part produced preferably in a forming process being formed tapered or funnel-like, and is put on the control pin20concentrically because of the center opening29. It is typically for the funnel-like (200) design of the control part21that a chamber22is provided which runs in the opening29if the control pin20has not been inserted.

The chamber22is accessible here on the side opposite the valve seat11, and the medium to be controlled flows through it in a suitable way.

It can be seen clearly that the design of the control part21according toFIG. 1has a continuous wall thickness. This results when a suitable control part is produced from a metal part in a forming punch-folding or punch-sinking process. This forming can be realized economically. At the narrow point201of the tapered or funnel-like (200) control part21limiting the opening29the material of the narrow point201is pressed or jammed in the circumferential groove24of the control pin in the following connecting process, and thus an exact connection which can also be mechanically stressed is produced. Alternatively the groove is filled by glue.

The control part21expands from the narrow point201upwards tapered or funnel-like, and then ends with a ring202with constant radius. The upper edge of the ring202forms also the end of the control part21and limits the chamber22.

In contrast to the suggestion according toFIG. 1the modification according toFIG. 2shows a varying control part as well as a modified design of the core30with a concentric (with reference to the axis of the control pin20) raised part31.

The design of the control part21shown inFIG. 2is also again funnel-like or, seen from the outside, tapered. The functioning of the control part shown here can be compared with the one ofFIG. 1and is identical. However, inFIG. 2the control part21has been generated in one plastic moulding process, so that the result is a somewhat larger wall thickness. Here also the wall thickness itself is not the same overall, this can be realized by suitable designs of the moulding tool. For a stable connection of the control part21consisting of plastic, fiber reinforced plastic (for example carbon fiber or glass fiber reinforced plastic), high temperature resistant plastic or highly resistant plastic on the control pin20also a ring groove24, or, if necessary, also other surface recesses are provided so that a positive locking is reached between the control pin20and the control part21.

In the embodiment shown here on the core30a raised part31facing the valve seat11is arranged concentric around the bearing of the pin20in the core30. Independent from the axial position27of the pin20(and therefore of the control part21) this raised part31projects in the chamber22of the control part21. However, a small opening gap (annular) remains between the raised part31and the annular section202through which the medium to be controlled can flow. This construction reaches a higher stability against pressure vibrations.

The suggestion according toFIG. 3substitutes the control part21formed of plastic inFIG. 2by the control part21according toFIG. 1which is made of metal. Here also the raised part31immerses in the chamber22, a gap remaining between the edge of the raised part31and the ring section202of the control part.

Although the invention has been described by exact examples which are illustrated in the most extensive detail, it is pointed out that this serves only for illustration, and that the invention is not necessarily limited to it because alternative embodiments and methods become clear for experts in view of the disclosure. Accordingly, changes can be considered which can be made without departing from the contents of the described invention.