The invention relates to a valve having a housing 1, a solenoid 5 arranged in the housing 1, a pin 7 movable by the solenoid, a piston 8 connected to the pin 7, and a seal. The piston 8 is composed of metal and has a seal 14 composed of a different material than the piston 8, wherein the seal 14 is arranged in the crown region 12 of the piston 8.
- 1-11. -11. (canceled)
- 12. A valve comprising:
a housing (1); a solenoid (5) arranged in the housing (1); a pin (7) movable by the solenoid (5); a piston (8) connected to the pin (7), the piston (8) having a crown region; and a seal (14) arranged in the crown region of the piston (8), the seal (14) having a sealing surface (15), wherein the piston (8) is made of metal and the seal (14) is made of a different material than the piston (8).
- View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
This is a U.S. national stage of International application No. PCT/EP2017/082715, filed on Dec. 13, 2017, which claims priority to German Application No. 10 2016 226 127.4, filed Dec. 22, 2016, the content of which are incorporated herein by reference.
The invention relates to a valve of a type having a housing, a solenoid arranged in the housing, a pin movable by the solenoid, and a piston connected to the pin.
Such valves are used, inter alia, as a diverter valve on the turbocharger in motor vehicles to open up a bypass to the suction side in overrun operation, and are thus known. In order to prevent excessive deceleration of the turbocharger, but also to ensure a fast launch, fast opening and closing of the valve is essential. In particular during the closing process, the immediate closure as a result of the abutment of the piston against a valve seat is of importance. For reasons of weight, the piston is therefore formed from plastic. The valve seat is formed by the housing of the turbocharger, on which the valve is flange-mounted. Owing to the high number of closing cycles required over the service life and the operational temperature loads, high demands are placed on the component with regard to the plastic and the design of the piston, in particular in the region of the sealing edge. The costs for such a piston correspond to this. Furthermore, in individual cases, there is a decline in the sealing action over the service life.
It is therefore an object of the invention to provide a valve with an improved sealing function over the service life. Here, the valve should be inexpensive.
This object may be achieved, according to one aspect of the invention, if the piston is made of metal and has a seal composed of a different material than that of the piston, and wherein the seal is arranged in the crown region of the piston.
The formation of the piston from metal with the seal arranged in the crown region permits the separation of the function of sealing from the piston itself. This allows the seal to be configured in a manner directed exclusively to the sealing function, such that the sealing function is improved. At the same time, in this way, the piston can be of simpler design, whereby its production is inexpensive. The considerably reduced complexity of the piston, in particular in the crown region, permits the production of the piston by deep drawing. A metal piston also has the advantage of higher temperature resistance, such that the valve according to an aspect of the invention can cover a wider field of application, in particular at relatively high temperatures.
Greater resistance to aggressive media and thus a longer service life are realized if the piston is composed of high-grade steel, preferably a chromium-nickel steel.
Good media resistance is achieved in the case of the seal in that a rubber, preferably ethylene propylene diene monomer (EPDM), or a plastic, preferably polyphthalamide (PPA), is used as the sealing material. Both rubber and plastic are well suited for sealing against metallic valve seats. Furthermore, they can compensate for positional inaccuracies owing to tolerances or over the service life.
According to one advantageous refinement, the connection of the seal to the piston is particularly simple if the seal is of annular form and, on its side facing away from the sealing surface, has at least 3, preferably 4 to 12 and in particular 5 to 8, integral moldings which extend through apertures which are arranged in the crown of the piston.
Owing to the elasticity of the seal material, the integral moldings may have a slightly larger cross section than the apertures through which they pass during the installation of the seal. In this way, the seal can be connected to the piston and is nevertheless held securely on the piston.
According to another advantageous refinement, even more reliable protection against a detachment of the seal from the piston is achieved in that the integral moldings have, at their free end, a material accumulation which can be generated with the production of the seal, in particular injection molding or vulcanization, or by retroactive hot calking, wherein the material accumulation forms an undercut with respect to the respective aperture in the piston.
In another refinement, the seal can be arranged on the crown of the piston in that the piston has an inwardly directed flanged portion in the region of the crown, in that the seal bears against the flanged portion, in that a metal part which forms the crown of the piston bears against that side of the seal that is averted from the flanged portion, and in that the metal part is connected to the piston. The connection of the metal part to the piston may be performed independently of this, preferably by pressing or welding.
Depending on the sealing requirements and the installation location, the seal can be adapted in a targeted manner. This can be realized in a simple manner by the thickness of the seal body, wherein the seal body is to be understood as being that part of the seal arranged outside the piston. It has been found here that a thickness of 0.3 mm to 5 mm, preferably of 0.5 mm to 3 mm, is advantageous.
The connection of the piston to the pin may be realized either by welding or riveting. Both types of connection have the advantage that the piston can be connected directly and thus without an additional component to the pin, which is likewise composed of metal. This is in contrast to a plastics piston, the connection of which to the pin requires an additional connecting part.
Owing to the greater stability of metal in relation to plastic, the wall thickness of the piston can be made significantly smaller. Depending on the field of use, it has proven to be advantageous if the metal of the piston has a thickness of 0.3 mm to 0.8 mm, preferably of 0.4 mm to 0.6 mm and in particular of 0.5 mm. Here, the smaller wall thickness of a metal piston in relation to a piston composed of plastic compensates for the higher density of metal in relation to plastic, such that the weight of the valve is not significantly affected.
The invention will be described in more detail on the basis of an exemplary embodiment. In the figures:
Thus, while there have been 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.