Valve-body arrangement and method for producing it, and valve having the valve-body arrangement

Abstract

A valve body arrangement for a hydraulic or pneumatic valve comprises two elements between which a valve body is retained. The two elements are welded together in a first region, preferably by the laser transmission method, and clamp the valve body in a second region with a force.

Claims

1. A method for manufacturing a valve body arrangement, wherein a valve body is retained between a first element and a second element, comprising: arranging the valve body between the first and second elements in a first region, the first and second elements directly bordering on each other in a second region, connecting the first and second elements in the directly mutually bordering second region in a first welding or melting process such that the valve body is retained between the first and second elements in the first region, wherein during the connecting in the first welding or melting process a retaining force with which the valve body is clamped in between the first and second elements is adjusted by exerting a force on the first and second elements such that the valve body is clamped in between the first and second elements in the first region.

2. The method according to claim 1, wherein upon the connecting in the first welding or melting process, material of one of the first and second elements is partly displaced, so that the first and second elements move toward each other.

3. The method according to claim 1, wherein the connecting in the first and/or a second welding or melting process is carried out as a laser transmission method.

4. The method according to claim 1, wherein a third element is arranged such that a valve inlet and a valve outlet are arranged coaxially.

5. The method according to claim 1, wherein the first element, the second element and a third element comprise plastic material by means of which the elements are interconnected in a form-locking or material-locking manner in the first and a second welding or melting process in the first region and/or in a third region.

6. The method according to claim 1, wherein the first element and/or a third element comprises a first material which is partly or completely transmissive to laser radiation of a certain wavelength, and the second element comprises a second material which is completely absorbent to the same laser radiation, or at least more strongly absorbent than the first material, and that the first and second materials are interconnected in a form-locking or material-locking manner in the first and a second welding or melting process.

7. The method according to claim 1, wherein a connecting interface between the first and second elements and/or the first and a third element is perpendicular to a force direction with which the valve body is retained between the first and second elements in the second region.

8. The method according to claim 1, wherein a connecting interface between the first and second elements and/or the first and a third element is parallel to a force direction with which the valve body is retained between the first and second elements in the second region.

9. The method according to claim 1, wherein at least one of the first, the second and a third element comprises glass fiber reinforced plastic material.

10. The method according to claim 1, wherein at least one of the first, second and a third element is an injection molded part.

Description

(1) Hereinafter the invention will be explained more closely by way of example with reference to the accompanying drawings. Therein are shown:

(2) FIG. 1A a valve having a valve body arrangement according to a first exemplary embodiment in the closed position,

(3) FIG. 1B the valve from FIG. 1A in the open position,

(4) FIG. 2A a valve having a valve body arrangement according to a second exemplary embodiment in the closed position,

(5) FIG. 2B the valve from FIG. 1B in the open position, and

(6) FIG. 3 a valve having a valve body arrangement according to a third exemplary embodiment in the closed position.

(7) FIG. 1A shows the arrangement of a valve body 4 in a valve 10, which can be for example a hydraulic or pneumatic valve. The valve 10 possesses a flow inlet A and a flow outlet B as well as a valve body 4 which blocks a passage between A and B. The pressure present on the flow inlet acts on a central region 4a of the valve body 4 configured as a sealing disk or membrane. From the opposing side the valve body 4 is urged axially by means of a biasing spring 3 against a sealing collar 5. In this position the valve body 4 closes the flow inlet A.

(8) As soon as the pressure present at the inlet A overcomes the opposing force exerted on the valve body 4 by the biasing spring 3, the valve body 4 moves or is deformed in its central region 4a and releases a passage to the outlet B, as represented in FIG. 1B. The motion or deformation of the valve body 4 is facilitated by a pressure compensation bore 14. To avoid an unintentional lateral shift of the valve body 4 at this moment of the open valve state, the valve body 4 is retained radially outside in an edge region 4b. For this purpose, the valve housing of the valve 10 comprises two elements 1 and 2 between which the valve body 4 is retained. In the represented exemplary embodiment, the valve body 4 is clamped in between the two elements 1 and 2 with a prescribed retaining force F.sub.R and thus retained in a force-locking manner. In addition, the valve body 4 is also prevented from slipping in the radial direction by form-locking engagement. For this purpose, a lug 1a of the element 1 engages a depression 4c of the valve body 4 which is located radially inside from the edge region 4b of the valve body 4.

(9) The two elements 1 and 2 are firmly interconnected. For this purpose, the element 1 is seated on a circumferential, axially protruding bearing shoulder 6 of the element 2 and welded to the element 2 continuously in this region. This results in a leakage-free seal of the elements 1 and 2, on the one hand, and in a firm connection of these two elements, on the other hand. At the same time, the retaining force F.sub.R can be adjusted with which the valve body is clamped in between the two elements, by urging the element 1 against the valve body 4 with a force F during the welding process. The superficially melted material in the region of the bearing shoulder 6 thus flows laterally into a recess 7, and the element 1 moves toward the element 2 to the corresponding extent until further motion is prevented by the valve body 4. From this moment the valve body 4 is retained between the two elements 1 and 2 with the defined force F or the reaction force F.sub.R, and this retaining force F.sub.R is frozen as soon as the connecting point is sufficiently cooled and the superficially melted materials have passed into a solid state again. As explained at the outset, the same result can be achieved also when material of only one of the two elements is superficially melted. The retaining force F.sub.R per unit area of the region 4b, i.e. the compression pressure in the region 4b, is considerably greater due to the small surface area of the region 4b than the pressure force F per unit area of the element 1, or than the contact pressure. Hence, a high compression pressure in the region 4b can already be achieved with low forces F.

(10) The superficial melting in the region of the bearing shoulder 6 is effected in this exemplary embodiment by means of a laser by the laser transmission method. For this purpose, the first element consists, at least in the region to be penetrated by radiation, of a material that is partly or preferably completely transmissive to laser radiation E of a certain wavelength. The element 2 has in contrast, at least in the region of the bearing shoulder 6, a material that is preferably completely absorbent to the same laser radiation E, but at least more strongly absorbent than the material of the element 1. The energy supplied by means of the laser beam thus heats the material of the element 2 in the relevant region. This has the consequence that the material of the element 2 superficially melts in this region and that due to the heat transmission the material of the element 1 also superficially melts in the accordingly bordering region. Hence, both materials are preferably plastics which in this way produce a material-locking connection between the two elements 1 and 2.

(11) It is equally possible, however, that only one of the two materials superficially melts. For example, the element 2 can be metallic or a plastic with a high melting point and heat up without superficially melting such that only the other element 1, which consists for example of plastic with a relatively low melting point, superficially melts in the accordingly bordering region. The melt of the element 1 can then flow into pores and/or undercuts of the element 2 and, after cooling, produce a form-locking connection between the two elements 1 and 2.

(12) The valve 10 can be inserted into an air spring cup of an air strut of an air spring system for a vehicle. The valve then acts as a residual pressure holding valve and thus allows a certain pressure to be held in the air strut. The desired pressure can be adjusted by means of the biasing spring 3. The stronger the biasing spring 3 is adjusted, the greater the required opposing force for overcoming the spring force is, i.e. the higher the residual pressure held in the air strut is, and vice versa. To be able to be inserted sealingly into a suitable opening, the valve 10 can have a sealing ring, such as an O ring (not represented), on its outer side, in particular on the outer side of the second element 2.

(13) FIGS. 2A and 2B show a second exemplary embodiment of a valve, in particular for employment as a residual pressure holding valve in an air strut of an air spring system of a vehicle, in the closed and open positions, which differs from the exemplary embodiment according to FIGS. 1A and 1B substantially only in that the connecting interface at which the two elements 1 and 2 are interconnected by means of laser radiation E is parallel to the direction of the force F with which the valve body 4 is retained between the two elements 1 and 2. In this second exemplary embodiment, the element 1 is inserted into the gap 8 of the element 2 without coming to lie against the element 2 with a circumferential collar, as was the case in the exemplary embodiment according to FIGS. 1A and 1B. Instead, the force F with which the element 1 is urged into the gap 8 of the element 2 acts directly on the valve body 4. In this state, the two elements 1 and 2 can be welded together all around in a sealing manner preferably by the laser transmission method again. As a result, the force F is frozen as the reaction force or retaining force F.sub.R of the valve body 4. This does not require a part of the superficially melted material to be displaced.

(14) To realize the connection between the two elements 1 and 2 by the laser transmission method, both elements can again consist of plastic with corresponding transmissivities or absorption properties for a certain wavelength of the laser radiation. Alternatively, the element 1 inserted into the gap 8 can for example be metallic and only the other element 2 consist of plastic that is transmissive to the laser radiation, which then superficially melts due to the heat transmission.

(15) FIG. 3 shows a third exemplary embodiment of a valve 11 in the closed position. As in the second exemplary embodiment, the connecting interface 6 at which the two elements 1 and 2 are interconnected by means of laser radiation E is parallel to the direction of the force with which the valve body 4 is retained between the two elements 1 and 2. Additionally, the valve arrangement of this third exemplary embodiment has a third element 2a which is connected by means of laser radiation E to the second element 2 in a region 13. Like the connection of the first element 1 with the second element 2, the connection of the third element 2a with the second element 2 is effected by means of laser radiation E in the radial direction. In this exemplary embodiment, the first element 1 forms a lower element, the second element 2 a middle element, and the third element 2a an upper element. In particular, the third element 2a is arranged on a side of the valve body 4 opposing the first element 1. The third element 2a has a recess for receiving a port 12 in the valve outlet B. Due to the three-part configuration of the valve 11, the valve inlet A and the valve outlet B can be arranged coaxially, so that the valve 11 has a smaller dimension in the radial direction than the valve 10 according to the first and second exemplary embodiments.

(16) As also in the other exemplary embodiments, the valve body 4 is configured as a membrane or sealing disk and urged against a sealing collar 5 axially via a sleeve 9 by means of a biasing spring 3 in order to close the valve passage. The valve body 4 has a lug 4d which engages a corresponding recess of the sleeve 9 in order to avoid a radial shift of the valve body 4. It will be appreciated that this can also be realized in the other exemplary embodiments.

(17) To realize the connection between the three elements 1, 2, 2a by the laser transmission method, the elements can, as in the other exemplary embodiments, consist of plastic with corresponding transmissivities or absorption properties for a certain wavelength of the laser radiation, the middle element 2 being more strongly absorbent to the laser radiation used than the lower element 1 and the upper element 2a. Alternatively, the lower element 1 and the upper element 2a can be metallic for example and only the middle element 2 consist of plastic that is transmissive to the laser radiation, which then superficially melts due to the heat transmission.

(18) Because the connection between the lower element 1 and the middle element 2 as well as the upper element 2a and the middle element 2 is effected by means of laser welding, a leakage-free seal of the valve arrangement is obtained. This requires no additional seals, so that the valve arrangement can be configured in a space-saving manner. Through the connection of the lower element 1 and the middle element 2 in the region 6 the valve body 4 is securely retained.

(19) The valve 11 according to the third exemplary embodiment can, like the valve 10 according to the first and second exemplary embodiments, be employed as a residual pressure holding valve in an air spring system of a vehicle. In particular, the valve can be inserted into an air spring cup of an air strut and allows a residual pressure in the air strut to be held even when the air spring system is switched off or during transport or storage of the air strut over a long time period.