Valve device for a motor vehicle

Abstract

Valve device for a motor vehicle comprising a housing, a flow channel (2) located in the housing (1), a flap (3) arranged in the flow channel (2) for closing the flow channel (2), wherein the flap (3) has areas in which an axis penetrating the flap (3) is fixed, and the axis (4) is rotatably mounted in the housing (1), and a valve seat (8) arranged in the flow channel (2), which is in contact with the flap (3) when it is closed, characterized in that the valve seat (8) is a ring (8) which is inserted into the flow channel (2) by means of a press-fit, that a sealing ring (7) seals the flow channel (2) against the inner wall of the ring (8) inserted into the flow channel (2), and that at least one section (9, 10) of the flow channel (2) adjacent to the valve seat (8) has a smaller cross-section than the inner diameter of the valve seat (8).

Description

[0001] The invention relates to a valve device for a motor vehicle comprising a housing, a flow channel located in the housing, a flap arranged in the flow channel for closing the flow channel, wherein the flap is attached to an axle, the axle is rotatably mounted in the housing, and a valve seat arranged in the flow channel which is in contact with the flap when it is in the closed position.

[0002] Such valve devices are used, for example, as throttle valves or exhaust gas recirculation valves and have been known for a long time. The rotatably mounted flap makes it possible to completely close the flow channel or to open it to such an extent that maximum mass flow is achieved. Accordingly, the valve device is designed according to the maximum mass flow and thus according to the free flow cross-section in the area of ​​the flap. With regard to mass flow control, the greatest challenge lies in achieving sufficient control accuracy at the minimum mass flow, where the flap is only pivoted a few degrees from the closed position. This requires careful coordination of the geometry and the material pairings between the flap and the flow channel.It is known to arrange a valve seat in the flow channel in the area of ​​the closed position of the flap, which is appropriately matched to the flap and, if applicable, to the seal arranged around the circumference of the flap. A disadvantage of this approach is that different valve devices with correspondingly matched flaps and valve seats must be provided for different requirements that demand varying maximum flow rates. Due to the precise matching required, the various valve devices are very complex. Furthermore, it is known from German patent applications DE 10 147 333 A1 and DE 10 2006 043 647 A1 to design a valve seat as a separate housing part to which the flow channel is flanged on both sides in the direction of flow.

[0003] The invention is based on the objective of creating a valve device with which different maximum mass flow rates can be achieved with minimal effort using only one flow channel cross-section.

[0004] The problem is solved using the features of claim 1.

[0005] By creating a smaller cross-section in the flow channel, extending only over a portion of the flow channel in the valve assembly, the requirement for maximum mass flow is no longer determined by the freely flowable cross-sectional area of ​​the flap and valve seat, but rather by the flow channel itself. This allows the other sections of the flow channel to be designed with different, and in particular larger, cross-sections. The decisive advantage is that larger valve seats with corresponding flaps can then be used. Thus, it is not necessary to develop a new flap with an adapted valve seat for every new maximum mass flow requirement; instead, existing flaps and valve seats can be used. Since adapting the flap and valve seat for control purposes is considerably more complex, using existing components leads to significant simplifications.In contrast, adapting a section of the flow channel to a new, smaller maximum mass flow rate involves significantly less effort, so that the valve device according to the invention covers a very wide range of applications. Existing housing structures can also be used, since the adaptation is limited to the flow channel.

[0006] In an advantageous embodiment, the section of the flow channel with the smaller cross-section is arranged downstream of the valve seat. This modification of the flow channel can be achieved with particularly little effort, since such valve devices generally have metal casting housings and the modified flow channel is already created during the casting process by means of a modified core.

[0007] A modified casting process for manufacturing the valve housing is avoided according to another embodiment by forming the flow channel with a smaller cross-section using an insert located within the flow channel and adjacent to the valve seat. This insert has a smaller cross-section than the inner diameter of the valve seat. The advantage of this embodiment is that not only the valve seat and flap, but also the housing itself, can be used for all new applications, not just one. Since the adaptation to new maximum mass flow rates is achieved solely through the insert, all other components can remain unchanged. The flow channel only needs to be prepared to accommodate the insert. This adaptation, however, can be carried out with minimal effort.

[0008] In another embodiment, the flow channel with a smaller cross-section is formed by two inserts arranged within the flow channel, with one insert positioned on each side of the valve seat, and both inserts having a smaller cross-section than the inner diameter of the valve seat. This embodiment creates a volume within the two inserts adapted to the smaller maximum mass flow rate, which improves the controllability provided by the flap arranged between the two inserts.

[0009] To enable and ensure a virtually turbulence-free flow around the valve and thus good controllability, at least one insert or flow channel is designed such that the smaller cross-section widens continuously towards the valve seat until it reaches the inner diameter of the valve seat. This design has the advantage that the reduction in cross-section only becomes significant at large valve opening angles, while at small opening angles, the large cross-section of the valve seat maintains good controllability.

[0010] In a simple embodiment, the insert or flow channel has a smaller cross-section than the valve seat and is rotationally symmetrical. If the maximum mass flow rate is only slightly reduced, further advantageous embodiments allow the insert or flow channel to have a dome-shaped cross-sectional reduction extending only over a portion of the circumference, preferably over a range of 90° to 180° of the circumference.

[0011] The arrangement of the valve seat and / or the respective insert in the flow channel is particularly easy when they are screwed or pressed in.

[0012] Turbulence in the flow caused by the decreasing cross-section can be reduced by ensuring that the cross-section of at least one insert transitions seamlessly into the cross-section of the flow channel. This means that the diameters of the at least one insert and the flow channel are the same at that point. This can be achieved, firstly, by reducing the cross-section of the flow channel. Since the flow channel must already have a smaller cross-section to accommodate the insert, adapting it to the cross-sectional dimensions of the insert requires minimal effort.

[0013] A continuous transition between the flow channel and the insert, without any modification of the flow channel, is achieved by the insert having a contour directed towards the flow channel, which widens from its smallest cross-section to the cross-section of the flow channel. This widening can be funnel-shaped, frustoconical, or have a concave or convex outer surface.

[0014] In a further embodiment, the cross-section of the flow channel is widened back to its original cross-section further along its length. This design ensures an uninterrupted transition from the housing's flow channel to the connected components in the flow path. No additional modifications or transition pieces are required.

[0015] The invention is explained in more detail using several exemplary embodiments. These show: Fig. 1 a valve device according to the invention, Fig. 2 the flow channel of the valve device according to Fig. 1 and Fig. 3 - 4 further embodiments of the valve device according to Fig. 1.

[0016] Fig. Figure 1 shows an exhaust gas recirculation valve with a housing 1, a flow channel 2 located in the housing in which a disc-shaped flap 3 is arranged. The flap 3 is fixedly connected to an axle 4, and the axle 4 is rotatably mounted in the housing 1. The axle 4 is driven by an electric motor 5 arranged in the housing 1, with a gearbox 6 interposed between the axle 4 and the electric motor 5.

[0017] Fig. Figure 2 shows part of the flow channel 2 after Fig. 1 in section. The disc-shaped flap 3 is fixed to the axis 4 by means of a welded connection to prevent rotation. In the illustration shown, the flap 3 is approximately half open. Sealing is achieved by a sealing ring 7, which is arranged in a groove in the flap 3. The sealing ring 7 seals the flow channel 2 against the inner wall of a ring 8 inserted into the flow channel 2, so that the ring acts as a valve seat 8. When the shaft 4 is rotated clockwise, the flap 3 opens by releasing a flow cross-section in the flow channel 2, which increases with increasing rotation. The valve seat 8 is pressed into the flow channel 2. Downstream of the valve seat 8, the flow channel 2 has a section 9 with a smaller cross-section than the inner diameter of the valve seat 8. The cross-section of section 9 defines the maximum mass flow rate of the valve device.For a defined fluid flow, the cross-section of the flow channel 2 widens continuously from the smallest cross-section in section 9 towards the valve seat 8, so that the cross-section changes without steps or discontinuities. The wall of the flow channel 2 is concave in this region 10. In the flow direction after section 9, the flow channel 2 widens to its original cross-section.

[0018] Fig. Figure 3 shows a further embodiment in which section 9 is not formed by the flow channel 2, but by an insert 11, the insert 11 having the same inner contour as in Fig. 2.

[0019] Fig. 3a shows a design with an application according to Fig. 3, wherein the dome-shaped inner contour of the insert 11 extends over 90° and thus only over a part of the circumference. It is also conceivable to have such a dome-shaped contour in the region 10 of the flow channel 2 according to Fig. 2 to train.

[0020] In Fig.4, an insert 11, 12 is arranged on both sides of the valve seat 8. The inserts 11, 12 have the same design and are arranged such that the smallest cross-section 13, 14 of each faces away from the valve seat 8. This arrangement, particularly due to the concave inner contour, results in a continuously changing cross-section, which ensures relatively good flow in the area of ​​the valve seat 8 and the inserts 11, 12. The design of the two inserts 11, 12 creates a region within the flow channel 2 with a volume adapted to the smaller maximum mass flow rate, allowing the controllability of this mass flow rate to be very precisely adjusted by means of the flap 3 arranged between the two inserts 11, 12.

Claims

[1] Valve device for a motor vehicle comprising a housing, a flow channel (2) located in the housing (1), a flap (3) arranged in the flow channel (2) for closing the flow channel (2), wherein the flap (3) has areas in which an axle penetrating the flap (3) is fixed, and the axle (4) is rotatably mounted in the housing (1), and a valve seat (8) arranged in the flow channel (2) which is in contact with the flap (3) when it is closed. characterized by , that the valve seat (8) is a ring (8) which is inserted into the flow channel (2) by means of pressing, that a sealing ring (7) seals the flow channel (2) against the inner wall of the ring (8) inserted into the flow channel (2), and that at least one section (9, 10) of the flow channel (2) adjacent to the valve seat (8) has a smaller cross-section than the inner diameter of the valve seat (8). [2] Valve device according to claim 1, characterized by , that the section (9, 10) of the flow channel (2) with smaller cross-section is arranged downstream of the valve seat (8). [3] Valve device according to claim 1 or 2, characterized by , that the flow channel (2) with a smaller cross-section is formed by an insert (11) arranged in the flow channel (2) and adjacent to the valve seat (8), wherein the insert (11) has a smaller cross-section than the inner diameter of the valve seat (8). [4] Valve device according to claim 1 or 2, characterized by , that the flow channel (2) with a smaller cross-section is formed by two inserts (11, 12) arranged in the flow channel (2), wherein one insert (11, 12) is arranged on each side of the valve seat (8), and that both inserts (11, 12) have a smaller cross-section than the inner diameter of the valve seat (8). [5] Valve device according to at least one of the preceding claims, characterized by, that the smaller cross-section of the at least one insert (11, 12) or of the flow channel (9) widens continuously in the direction of the valve seat (8) up to the inner diameter of the valve seat (8). [6] Valve device according to at least one of the preceding claims, characterized by , that the valve seat (8) and / or the respective insert (11, 12) is screwed or pressed into the flow channel (2). [7] Valve device according to at least one of the preceding claims, characterized by , that the cross-section (10) of at least one insert (11, 12) transitions continuously into the cross-section of the flow channel (2). [8] Valve device according to at least one of the preceding claims, characterized by , that the cross-section of the flow channel (2) widens again to the original cross-section in the further course.

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