1. Field of the Invention
The invention pertains to a filling valve for fastening to the edge of a pressure vessel, the filling valve having a fastening part having curved outer surfaces and enclosing a filling channel.
2. Description of the Related Art
U.S. Pat. No. 6,467,760 discloses a filling valve of the general type in question; it is welded into an open edge of the pressure vessel. As can be derived from
A pressure vessel of the same basic type with a cylindrical filling valve is described in U.S. Pat. No. 6,450,307. In this variant, the filling valve has a conical tip, which is welded into the edge, the purpose again being to minimize the formation of folds.
As a general rule, the formation of folds can be reduced by increasing the ratio of the length of the filling valve to its height, because then the folds can distribute themselves over a greater distance along the edge. But there is also the problem that the pressure vessel, when used in a vibration damper, is subjected to very high external pressures. It is disadvantageous in this regard that the filling valves are frequently made of plastic, which cannot withstand such pressures under certain conditions.
In U.S. Pat. No. 6,467,760, a filling valve is installed within a solid guide part of the vibration damper and is therefore well protected. In U.S. Pat. No. 6,450,307, an additional coating is used on the edges in the area of the filling valve. The use of an additional coating is not optimal for reasons of production technology, nor is it possible to provide a coating inside a guide part in all types of vibration dampers.
Another solution consists in providing the filling valve with external ribs, extending parallel to the edge. Such ribs, however, negatively affect the length-to-height ratio and thus promote the formation of folds.
The task of the present invention is to realize a filling valve for a pressure vessel which can withstand high external pressures.
This task is accomplished according to the invention in that the fastening part has a pressure-compensating space with a cross section which is greater than that of the filling channel.
The great advantage is that the effective pressure inside the pressure vessel can be used as a counterforce to oppose the external pressure.
In another advantageous embodiment, the cross-sectional form of the pressure-compensating space is adapted to the cross-sectional form of the fastening part in such a way that the thickness of the walls forming the curved surfaces of the fastening part is as uniform as possible. A constant wall thickness for a filling valve made of plastic is desirable to avoid defects and warping. In addition, relatively thin walls can be used. This makes it easier to soften the edges when they are being welded to the filler piece, which thus increases the quality of the weld.
During welding, the edges of the pressure vessel are clamped onto the fastening part of the filling valve, but the pressure inside the pressure vessel is still the same as atmospheric pressure and is therefore of no use, i.e., not high enough to keep the fastening part from being squeezed shut during clamping. So that the mechanical load during welding can be absorbed more effectively, therefore, at least one reinforcing rib is provided inside the pressure-compensating space.
To create favorable boundary conditions for the welding operation, the minimum of one reinforcing rib inside the pressure-compensating space is shorter in the axial direction than the depth of the pressure-compensating space. A reinforcing rib of this type is also in principle a cooling rib, which dissipates the heat acting on the fastening part during welding. For this reason, the reinforcing rib should be as short as possible in the axial direction.
It is not important for the weld to be optimal over the entire axial length of the fastening part. The weld must simply be leak-tight toward the outside. For this reason, the minimum of one reinforcing rib proceeds from a bottom part of the pressure-compensating space. In the direction toward the pressure vessel, the fastening part can therefore be fabricated without a reinforcing rib over a certain part of its length, as a result of which the cooling rib effect cannot occur there, and consequently the optimal conditions for a high weld quality are obtained. At the same time, the wall of the fastening part is adequately supported during the welding process.
In an alternative variant, it is provided according to the invention that the fastening part, in the cross section parallel to the filling channel, is shorter in the direction toward the interior space of the pressure vessel than in the same plane at the outer edge. To avoid an oriented installation position, it is effective here to select a wedge-shaped cross section for the fastening part. This variant almost completely eliminates the formation of folds at the edges of the pressure vessel.
In addition, the fastening part can become shorter with increasing distance from the outer edge area of the pressure vessel, i.e., the fastening part slants inward from the outer edge of the filling channel. The basic idea is to minimize the volume of the fastening part which is present in the edge area of the pressure vessel.
In spite of its possibly wedge-shaped cross-sectional profile, the filling channel inside the fastening part is partially formed by the sleeve of the pressure vessel. Thus an extremely flat transition from the fastening part to the pressure vessel is created, because the height of the fastening component in the area of the filling channel can be reduced by an amount equal to nearly twice the conventional wall thickness of the fastening part.
In addition, the fastening part can have extension fins in the edge area. These extension fins are intended to increase the usable length of the fastening part and thus help to decrease the formation of folds in the pressure vessel.
Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims. It should be further understood that the drawings are not necessarily drawn to scale and that, unless otherwise indicated, they are merely intended to conceptually illustrate the structures and procedures described herein.
The pressure tube 7 is surrounded by a container tube 15. The inside wall of the container tube and the outside wall of the pressure tube form a compensating space 17, which is completely filled by damping medium and a gas-filled pressure vessel 19, which extends up as far as a piston rod guide 21. At the bottom end of the working space 11, a bottom piece is located, which can be provided with a check valve 23 and a damping valve 25.
When the piston rod moves, the volume displaced by the piston rod is compensated by a change in the volume of the pressure vessel 19.
Referring to
It can be seen in
Inside the pressure-compensating space 45, at least one reinforcing rib 47 proceeds in a direction parallel to the filling channel 41. The rib starts from the bottom 49 of the pressure-compensating space. The length Z of the minimum of one reinforcing rib 47 inside the pressure-compensating space 45 is shorter in the axial direction than the depth T of the pressure-compensating space 45.
When, as a result of the movement of the piston rod, an elevated pressure is produced inside the compensating space 17 of the vibration damper, the filling piece 31 is subjected to external load in the area of the fastening part 37 across the edge 29 of the pressure vessel 19. In the interior of the pressure vessel, an opposing pressure builds up, which also acts in the pressure-compensating space 45 from the inside toward the outside, so that the pressure load on the fastening part 37, of the filling valve 31 remains comparatively low.
Thus, while there have shown and described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.
Number | Date | Country | Kind |
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10 2004 005 196.8 | Feb 2004 | DE | national |