VALVE

Description

[0001] The invention relates to a valve according to claim 1.

[0002] Such valves are used, among other things, as bypass valves on turbochargers in motor vehicles (see, for example, US 2013 / 313455 A1, WO 2014 / 068765 A1 or WO 2016 / 041659 A1) to release a bypass to the intake side during overrun operation and are therefore well known. In order to prevent excessive braking of the turbocharger, but also to ensure rapid start-up, rapid opening and closing of the valve is essential. Particularly during closing, immediate closure by the piston coming into contact with a valve seat is important. The valve seat is formed by the housing of the turbocharger, to which the valve is flanged. In addition, the axially movable piston must be sealed against the housing. For this purpose, it is known to arrange a V-shaped seal in the housing, the legs of which rest against the second housing part and against the outer surface of the piston.This seal also requires fixation in the housing section to ensure a tight fit against the piston. To achieve this, the seal is pressed onto the second housing section by another component. However, this requires additional design effort, which leads to higher costs for such valves.

[0003] The invention is therefore based on the object of creating a valve with improved sealing function. At the same time, the valve should be simpler in design and cost-effective.

[0004] The object is achieved in that the seal is connected to the second housing part, wherein the seal surrounds a region of the second housing part in such a way that this region forms at least one undercut for the seal.

[0005] Connecting the seal to the housing part by the seal surrounding an area of ​​the second housing part in such a way that an undercut is formed ensures that the seal sits securely and reliably on the housing part. An undercut is understood to be a design of the seal and / or the housing part that does not allow removal of the seal from its predetermined position by means of a simple translational or rotational movement, or at least makes it so difficult that removal of the seal is only possible with damage to the seal. The advantage of the valve according to the invention is that the at least one undercut reliably holds the seal in its position over its service life. Additional fastening elements are not necessary for this. This allows the production of a particularly cost-effective valve.Furthermore, undercuts can be created even in small dimensions, so that the valve does not require any additional installation space in the area of ​​the second housing part.

[0006] In a simple embodiment, the undercut comprises at least one area, with this area being formed by a radius. In the simplest case, the end of the second housing part facing away from the housing is angled. The angle can be between 5° and 180°, preferably 90°. It has been shown that the security against loosening increases with increasing angle.

[0007] The security against the seal coming loose can also be increased by having several areas formed by radii form the undercut.

[0008] In another advantageous embodiment, the undercut comprises at least one region that has at least one recess, preferably 2 to 12 recesses, and in particular 4 to 8 recesses. By filling these recesses, the seal is inseparably connected to the second housing part.

[0009] Although each of the undercuts described above provides sufficient security against seal loosening on its own, it may still be useful to provide a combination of radiused areas and recesses, especially if the valve is used under particularly harsh external conditions.

[0010] In order to achieve a good sealing effect with low wear over the entire service life, an advantageous design is to manufacture the seal from a fluororubber (FKM rubber). This material is sufficiently robust and allows reliable operation of the valve even at temperatures of 180 °C.

[0011] In order to achieve a particularly secure connection with the second housing part, the seal can be vulcanized onto the second housing part.

[0012] According to a further advantageous embodiment, the service life of the seal is increased by the seal having a sealing lip acting in the axial direction. This alignment of the sealing effect ensures that the seal only comes into contact with the piston in one position, namely the end position. Permanent contact with the piston, especially during piston movement and the associated friction, is avoided.

[0013] In a particularly advantageous embodiment, good resistance to a wide variety of flowing media and media mixtures, preferably exhaust gas from an internal combustion engine, is achieved by making the second housing part of metal, preferably stainless steel, in particular a chromium-nickel steel. Furthermore, the second housing part can also be formed with thin wall thicknesses in the range of 0.3 mm to 3 mm, preferably 0.5 mm to 1 mm, with sufficient dimensional stability.

[0014] According to a further advantageous embodiment, the second housing part can be manufactured particularly cost-effectively as a deep-drawn part. The shape of the second housing part can be achieved in a single work step without any further processing.

[0015] Likewise, it is advantageous if the piston is made of metal, preferably stainless steel, in particular a chromium-nickel steel. Such a piston can also be manufactured by deep drawing, which allows the sealing surface for the seal on the second housing part to be formed in a single step. The valve according to the invention can thus be manufactured particularly cost-effectively.

[0016] By arranging an axially acting seal that only interacts with the piston when it is closed, contact between the seal and piston is limited to a period when the piston is at rest, including a period immediately before the piston comes to rest. This means that the piston and seal already touch shortly before the closed position. When the piston moves for the last time into the closed position, the seal is deformed so that the sealing surfaces are preloaded against each other. The axially acting seal therefore prevents the seal from coming into contact with the piston during the opening and closing movement of the piston, which would otherwise cause friction. This prevents wear due to friction, and improves the service life of the seal.

[0017] The invention is described in more detail using an exemplary embodiment. It shows Fig. 1 is a sectional view of the valve according to the invention, Fig. 2 is an enlarged view of the second housing part and Fig. 3, 4 is a further embodiment of the second housing part.

[0018] Figure 1shows the valve, comprising a housing 1 with a one-piece molded-on socket 2 for electrically connecting the valve. The housing 1 further has a molded-on flange 3 and three bores 3a, via which the housing 1 is flange-mounted to a turbocharger (not shown) in the area of ​​the bypass line 4. In the installation position shown, a second housing part 13 adjoins the flange 3. A solenoid 5 with a coil 6 and a metal pin 7 is arranged in the housing 1. The metal pin 7 is connected to a pot-shaped piston 8, which has an axially projecting annular seal 10 on the circumference of its base 9. In the closed position shown, the seal 10 rests on the valve seat 11 to close the bypass line 4, so that no medium can flow from the line 4 into the line 12. A spring 7a presses the piston 8 towards the valve seat 11.

[0019] Figure 2shows the second housing part 13 with its cylindrical basic shape and the piston 8 with its cylindrical outer surface 14 in the closed position. Housing part 13 and piston 8 are deep-drawn parts made of chrome-nickel steel. The second housing part 13 has a radially outward-facing edge 15 at its end facing the housing 1. An O-ring acting as a seal 16 is arranged in the housing 1 concentrically to the edge 15. The housing 1 has a cylindrical section 17 extending from the solenoid 5 in the direction of the piston 8. The second housing part 13 is pressed onto the cylindrical section 17 until the edge 15 rests against the housing 1. To provide a defined contact surface for pressing in, the second housing part 13 has a cylindrical outer surface with two diameters.The larger diameter 18 is aligned with the housing 1 and is larger than the cylindrical section 17, while the smaller diameter 19 is selected so that the inner side forms the contact surface for the press connection with the section 17. The area of ​​the larger diameter 18 serves to decouple the contact surface 15 on the housing 1 and the press connection in the area of ​​the smaller diameter 19.

[0020] The second housing part 13 further has, at its end facing away from the housing 1, a collar 20 which is bent over by 90° and points radially inward. A seal 21 arranged on the second housing part 13 encloses an area of ​​the housing part 13. This area comprises part of the cylindrical outer surface 19 and the collar 20. The outer surface 19 and the collar 20 form an undercut which prevents the seal 21 from becoming loose. The seal 21 made of fluororubber consists of a base body 22 which surrounds the aforementioned area on the second housing part 13 and a sealing lip 23 pointing towards the housing. The sealing lip 23 interacts with a sealing surface 24 on the piston 8 in the form of an axial seal. For this purpose, the piston 8 has, at its end facing the housing 1, a radially outwardly projecting edge which rests on the sealing lip 23 when the valve is closed.

[0021] The seal 10 is located on the base 9 of the piston 8. It is made of fluororubber. The seal 10 is vulcanized onto the piston 8. The base 9 has several recesses 24 filled by the seal 10. In this way, the seal 10 is permanently connected to the piston 8.

[0022] Figure 3 shows the second housing part 13 without the seal 21. The collar 20 has 6 recesses 25, which also form undercuts for the seal 21, since the seal fills the recesses 25.

[0023] Figure 4 shows the second housing part 13 with the seal 21 and the sealing lip 23 aligned with the piston.

Claims

1. Valve having a housing (1), a solenoid (5) arranged in the housing, a pin (7) movable by the solenoid, and a pot-shaped piston (8) which is connected to the pin and which, at the circumference of its base, has an axially projecting annular seal (10) which bears against a valve seat (11) in a closed position, wherein a second housing part (13) is provided which bears against the housing and which partially accommodates the piston, and a seal (21) arranged between the second housing part and the piston, characterized in that the seal (21) arranged between the second housing part (13) and the piston (8) is connected to the second housing part (13), wherein the seal (21) arranged between the second housing part (13) and the piston (8) surrounds a region of the second housing part (13) such that said region forms at least one undercut (20, 25) for the seal (21) arranged between the second housing part (13) and the piston (8).

2. Valve according to Claim 1, characterized in that the undercut (20) comprises at least one region which is formed by a radius.

3. Valve according to Claim 1, characterized in that the undercut (25) comprises at least one region which has at least one recess, preferably 2 to 12 recesses and in particular 4 to 8 recesses.

4. Valve according to at least one of the preceding claims, characterized in that the seal (21) arranged between the second housing part (13) and the piston (8) is composed of an FKM rubber.

5. Valve according to at least one of the preceding claims, characterized in that the seal (21) arranged between the second housing part (13) and the piston (8) is vulcanized on the second housing part (13).

6. Valve according to at least one of the preceding claims, characterized in that the seal (21) arranged between the second housing part (13) and the piston (8) has a sealing lip (23) which acts in an axial direction.

7. Valve according to at least one of the preceding claims, characterized in that the second housing part (13) is composed of metal, preferably of high-grade steel, in particular a chromium-nickel steel.

8. Valve according to at least one of the preceding claims, characterized in that the second housing part (13) is a deep-drawn part.

9. Valve according to Claim 8, characterized in that the piston (8) is composed of metal, preferably of high-grade steel, in particular of a chromium-nickel steel.

10. Valve according to at least one of the preceding claims, characterized in that the piston (8) is a deep-drawn part.