KR20020087083A - Flap valve - Google Patents

Abstract

A valve flap 14 pivotable between the valve tube 13 guiding the gas flow and an open position arranged in the valve tube 13 to open the tube section to the maximum and a closed position to cover the tube section. A flap valve for gas flow control, wherein the valve flap is a valve which is fixedly seated on an adjustable flap shaft 15, in order to obtain a high density of the flap valve with the smallest possible moment of rotation. Tube end 131 is inclined such that annular tube edge 131 is in a plane extending with respect to tube axis 32 under acute angle β. The flap valve 14 has a substantially elliptical outer contour and within the valve tube 13, near the inclined tube end, such that its surface normal 20 forms an acute angle α with the tube axis 132 or Is arranged at the end. The flap valve 14 and / or the valve tube 13 are formed to be able to tilt or be elastically deformed in whole or in part.

Description

Flap valve

In the configuration of the throttle valve for controlling the exhaust gas flow in the exhaust gas channel of the internal combustion engine (DE 43 05 123 A1), a flap shaft which supports the throttle valve and extends parallel to the flap surface of the throttle valve is provided via a bearing bore. It is guided on both sides in the channel wall of the exhaust gas channel and each projects at this point through the bearing sleeve. In order to obtain greater density in preventing flap operation, the bearing sleeve initially axially tensioned in each bearing housing through the spring force is displaced inside the bearing housing, so that the throttle formed in the channel wall The size deviation between the stop face for the valve and the flap shaft bearing is automatically compensated when the throttle valve is first closed.

DE 199 34 113.3, which is not a prior publication, suggests the use of a flap valve of the type mentioned at the outset as an exhaust gas recirculation valve for dosing mixing of the exhaust gas to fresh air drawn into the suction tube of the internal combustion engine. For this purpose an opening is provided in the sheath of the suction tube of the suction tube, and the flap valve is inserted into the opening in an airtight manner together with the valve outlet. The valve flap is arranged in a thin-walled tube to adjust the flap, with the flap shaft acting obliquely to the flap face and the thin film tube is radially introduced into the rigid valve tube and secured to the valve tube as a tube section. Through the corresponding shape of the valve flap, the valve flap is in close contact with the inner wall of the resilient thin wall tube and insulates the tube cross section in a hermetic manner, so that a separate seal between the valve tube and the valve flap can be omitted.

The present invention relates to a flap valve for gas flow control according to the preamble of claim 1, 2, 3 or 4.

1 is a longitudinal sectional view of a flap valve used as an exhaust gas recirculation valve;

FIG. 2 is a cross-sectional view of the valve flap in the flap valve according to FIG. 1 taken along line II-II. FIG.

3 and 4 are perspective views of the flap valve, within two different pivot points of the valve flap;

FIG. 5 is a plan view of the flap valve seen in the direction of arrow V in FIG. 4; FIG.

6 and 7 are perspective views of a modified flap valve, within two different pivot points of the valve flap.

8 is a perspective view of another embodiment of a flap valve.

9 and 10 show respective flap valves according to FIGS. 1 to 4 to show the inclination of the valve tube (FIG. 9) and the valve flap (FIG. 10).

The flap valve according to the invention, each of which has the features of one of the preceding claims, has the advantage of reaching high density with a small moment of rotation when closed. The flexibility of the valve tube and / or valve flap and the tilting of the valve tube and / or valve flap give a relatively compensated voltage level upon closing of the flap valve, which, despite the high density within certain symmetrical limits, Do not include mechanical buffers. Through the inclination of the tube end, part of the flap contour during the movement of the valve flap is outside the valve tube, so only a partial contact is made, so a very small rotational moment is sufficient to adjust the valve flap. Only after closing the flap geometry is surrounded by the geometry of the valve tube and higher operating moments are obtained through deformation and tilting of the valve tube and / or valve flap. Furthermore, by selecting the flap inclination angle formed from the surface normal of the valve flap and the tube axis of the valve tube, the characteristic curve of the flap valve can be changed freely with respect to the maximum flow rate and the small amount of dosing. The smaller the flap tilt angle, the flap valve opens the smaller open cross section by the tube tilt. In addition, through the inclined position of the valve flap, its pivot angle between the closed position and the maximum open position extends by 180 °, so that the extended pivot path allows for a very sensitive amount at the beginning and at the end of the closing movement of the valve flap. Dosing is reached.

With the method described in another claim, another preferred embodiment and improvement of the flap valve as set forth in claims 1, 2, 3 or 4 is possible.

According to a preferred embodiment of the present invention, the flap shaft is tilted under an acute angle with respect to the surface normal of the valve flap. The coincidence of the surface normal and the axis of the flap shaft is excluded, as if both lines are aligned at right angles to each other. Preferably the flap shaft is arranged such that the shaft axis of the flap shaft is in line with the tube axis.

According to a preferred embodiment of the invention, the valve flap comprises an edge that defines its outer contour and the edge is rounded convex, ie in the direction of the surface normal of the valve flap. This has the advantage that the valve tube positively adheres to the flap valve in the closed position through deformation and / or tilting, thus obtaining a high density without continuously deforming the valve flap as in the case of having an outer contour of sharp edges.

According to a preferred embodiment of the invention, the valve tube can be elastically deformed at least in the closed region of the valve flap and formed into a thin wall. The dimension of the outer contour of the valve flap is larger than the dimension of the inner contour of the valve tube in the closed region of the valve flap. The valve tube can thus be well adhered to the valve flap and at the same time tilted with respect to the plane through different operating points of the valve flap, which makes the density very high. By changing the tube fixture in the tube end region turned away from the inclined tube end, the maximum closing moment and the rising properties of the closing moment can also be changed.

In order to bring the valve tube into close contact with the valve flap, it is important that the wall thickness of the valve tube is not too large and the inner diameter of the valve tube is not too small. On the contrary, for reasons of stiffness and vibration the wall thickness of the valve tube should not be too small and the diameter of the valve tube should not be chosen too large. According to a preferred embodiment of the present invention the thin wall tube has a wall thickness between 0.05 mm and 2 mm and the inner diameter of the valve tube is selected between 5 mm and 200 mm.

According to a preferred embodiment of the invention the valve tube is corrugated in the form of bellows in the tube section opposite the inclined tube end. The tube section supports the inclination point and the inclination of the valve tube, thus reliably preventing the mechanical buffer at the flap valve, which better surrounds the valve flap through the valve tube. By tilting the valve tube, the valve flap can be rotated without a buffer despite its larger outer contour than the inner contour of the inclined tube end. This simplifies the controllability of the flap valve and at the same time minimizes the risk of mechanical tightening and in some cases size fluctuations, which may be less severely affected through the point of inclination of the valve flap relative to the valve tube.

The flap valve according to the invention is preferably used as an exhaust gas recirculation valve in an exhaust gas recirculation line of an internal combustion engine or as a throttle valve unit in an inlet air line of a suction pipe of an internal combustion engine.

The invention is explained in more detail in the following detailed description by means of the embodiments shown in the drawings.

The flap valve 10 shown in perspective in FIGS. 3, 4 or 6, 7 is used as an exhaust gas recirculation valve in the suction tube of the internal combustion engine, in the embodiment according to FIG. 1. The valve comprises a suction tube 11 for sucking air guided towards the internal combustion engine, in which a throttle valve, not shown, for controlling the air flow is generally arranged. An opening 12 is formed in the shell of the suction tube 11, the axis of the opening being aligned at right angles to the axis of the suction tube 11.

The flap valve 10 shown in perspective view in FIGS. 3 and 4 and shown in longitudinal section in FIG. 1 is a valve tube 13 with a thin wall, flexible and optionally elastically deformable and having a controllable tube cross section 135. And a valve flap 14 arranged in the valve tube 13, the flap being fixed to the front end of the flap shaft 15, and through the rotation of the flap shaft 15 of the valve tube 13. It may be pivoted between an open position for maximum opening of the tube cross section 135 and a closed position covering the tube cross section 135 of the valve tube 13 (FIG. 1). The valve tube 13 is fixed to the valve base 16 as its tube end and the base can be fixedly connected to the suction tube 11. The valve base 16 is formed with a flange 22 having fixing holes 21 for constituting the exhaust gas recirculation line. The tube section 134 of the valve tube 13 inserted in the valve base 16 is formed in a bellows shape, so that the valve tube 13 can be tilted relative to the flap shaft 15 within a fixed area with a possibility of tilting. The flexibility is configured. The free tube end of the valve tube 13 opposite the tube end is inclined so that the annular tube edge 131 is located in a plane extending with respect to the tube axis 132 of the valve tube 13 under an acute angle β. The angle β is represented by the tube tilt angle β below. After inserting the flap valve 10 into the opening 12 of the suction tube 11 and fixing the valve base 16, the valve tube 13 protrudes the inner wall 111 of the suction tube 11. The edge point 133 of the tube edge 131 most preferably axially reset from the tube end is located directly on the inner wall 111 of the suction tube 11.

The flap shaft 15, which supports the valve flap 14 at one end, is rotatably received in the bearing bore 18, which, together with the bearing portion 17, penetrates the sheath of the suction tube 11, at its shaft end. 151 protrudes from the suction tube 11. At the shaft end 151, a servo motor 19 is engaged with the suction tube 11 and for operating the flap valve 10. 1 to 4, the flap shaft 15 is coaxially aligned with respect to the tube axis 132 of the valve tube 13. However, the shaft may be inclined up to 5 ° with respect to the tube shaft 132, and basically between the shaft 152 of the flap shaft 15 and the surface normal 20 of the valve flap 14 the shaft tilt angle ( The acute angle r represented by r) (FIG. 1) must be maintained.

The valve flap 14 has an elliptical or approximately elliptical outer contour and is arranged at or near the inclined tube end in the valve tube 13, as shown in the cross-sectional view of FIG. An axis 132 and an acute angle α (FIG. 1), which is represented by the flap tilt angle α in the following, are formed. As shown in FIG. 1, the outer contour of the valve flap 14 is rounded by convex expansion of the edge surface 141 of the valve flap 14 defining the outer contour in the direction of the surface normal 20 (FIG. 1). do. The rounding of the edge surface 141 causes the valve flap 14 to be enclosed through the flexible thin wall valve tube 13 without continuous deformation of the valve tube 13 in the closed position of the valve flap 14. A flap tilt angle α formed by the surface normal 20 of the valve flap 14 and the tube shaft 132 and a tube tilt angle β formed between the plane and tube shaft 132 of the inclined tube end (FIG. 1) Can be selected irrespective of each other, the selection area for the flap tilt angle α is set between 1 ° and 89 ° and the selection area for the tube tilt angle β is between 3 ° and 85 °. Corresponding to the angle α, β selected, the insertion depth must be set into the valve tube 13 of the valve flap 14. If the flap tilt angle α is chosen to be larger than the tube tilt angle β, for example, the insertion depth of the valve flap 14 into the valve tube 15 should be larger. 1 to 4, the standard case is shown. In this embodiment, the flap tilt angle α and the tube tilt angle β are 45 °, respectively. In the embodiment of FIGS. 6, 7 the flap tilt angle α is approximately 30 ° and the tube tilt angle β is approximately 45 °. The pivot point 142 of the valve flap 14, located at the front end of the flap shaft 15, is always inside the valve tube 13 and is pivoted from the inclined tube end to ensure the closed position of the valve flap 14. Have directional spacing. The axial spacing that defines the insertion depth in the valve tube 13 of the tilted adjusted valve flap 14 may be arbitrarily selected, but is always widest relative to the tube end on the outer contour of the tilted adjusted valve flap 14. The forwardly located edge point 143 should be determined so as to be in front of the edge point 133 of the tube edge 131 lying most widely behind, at all pivot points of the valve flap 14 (FIGS. 3, 4). Keeping the above gap allows the valve flap 14 to be pulled out of the valve tube 13 and the flap valve 10 to open the tube cross section in its open position. The larger the axial gap from the inclined tube end, the smaller the maximum flow rate in the open position of the flap valve 10.

In order to reach a high density assuming that the valve tube 13 is hermetically sealed to the valve flap 14, the geometry of the flap, i.e. the outer dimension of the valve flap 14, is the internal geometry of the tube, i.e. the valve Since the flap 14 should be selected to be larger than the dimensions of the inner tube cross section within the closed region, the flap contours upon closing of the flap valve 10, ie when the valve flap 14 is turned into the valve tube 13. With respect to the valve tube 13 is deformed. At the same time, through the valve flap 14 which is gradually turned into the valve tube 13 during the closing process, the valve tube 13 has a tube shaft 132 and a flap shaft 15 around the intersection as shown in FIG. 9. Tilt from axis 152. The intersection point coincides with the pivot point 142 of the valve flap 14 at the front end of the flap shaft 15.

9 shows the valve tube 13 pulled out from its inclined position by a tube inclination angle δ of, for example, 5 ° in this embodiment, and the non-tilted valve tube 13 is in a direction not different from that of FIG. It is shown by the dotted line. As mentioned, the tube cross section provided for turning against the valve flap 14 through tilting is expanded so that mechanical tightening of the valve flap 14 in the valve tube 13 is prevented. The valve flap 14 can always be rotated, despite the larger flap contours compared to the tube contours. This simplifies the controllability of the flap valve 10 and prevents mechanical tightening in the flap valve 10 when the size varies with manufacture. The flap contour depends on the flap inclination angle α, and the smaller flap inclination angle α reduces the flap plane, but the point of action of the tilt force on the valve tube 13 is moved into the tube and it is around the intersection point P. Setting a valve near the closed position becomes difficult because a larger tilt force is required to tilt the valve tube 13. Since the outer contour of the valve flap 14 preferably matches the valve tube 13, the face of the valve flap 14 projected onto the inner tube cross section 135 forms a circle and the diameter of the circle is a valve tube ( Continuously deflected from the inner tube diameter to not equal to or greater than 20% of the inner tube diameter of 13).

In order for the thin-walled valve tube 13 to be in close contact with the valve flap 14 in the closed state, the wall thickness of the valve tube 13 should not be very large and the inner diameter of the valve tube 13 should not be very small. . On the other hand, for reasons of strength and vibration, the wall thickness of the valve tube 13 should not be selected very small and the diameter of the valve tube very large. The above optimization of the contradictory requirement is obtained by the inner diameter of the valve tube 13 being between 5 mm and 200 mm and the wall thickness of the valve tube 13 being between 0.05 mm and 2 mm.

For the embodiment of the flap valve 10 having a larger flap structure compared to the tube structure, instead of the possibility that the valve tube 13 can be tilted, it will be tilted relative to the flap shaft 15 as shown in FIG. 10. A possibility may be provided to the valve flap 14. The valve tube 13, which can be elastically deformed here, is carried out rigidly, ie cannot be tilted, while the valve flap 14 is formed to be tilted at the pivot point 142. Instead of or in addition to the possibility that the valve flap 14 can tilt, the flap contour can be designed in thin wall. The elliptical face of the valve flap 14 is larger than the inner cross section of the valve tube 13 surrounded by the tube edge 131 at the inclined tube end. When the flap valve 10 is open, the valve flap 14 moves partially from the valve tube 13 and the valve flap 14 has the inclined position shown in FIG. 1 and the shaft inclination angle r is at this position. Between the surface normal of the valve flap 14 and the axis 152 of the flap shaft 15, ie the inclination of the valve flap 14 with respect to the flap shaft 15, r = 45 °. In the closing process, the valve flap 14 is gradually retracted into the valve tube 13, the valve tube 13 is deformed because the flap structure is larger and at the same time the valve flap 14 is around its pivot point 142. It is inclined or deformed in the furnace flap shaft 15. In the closed position of the flap valve 10 shown in FIG. 10, the valve flap 14 is tilted to the maximum and the shaft inclination angle r extends from 45 ° to 48 ° in this embodiment and the valve flap 14 is It is steep with respect to the flap shaft 15 and has a larger flap inclination angle α, ie more steeply adjusted with respect to the tube axis 132 of the rigid valve tube 13. (When the shaft 152 of the flap shaft 15 is in line with the tube shaft 132, the flap tilt angle α and the shaft tilt angle r are always the same.) As mentioned, the valve flap 14 is By tilting the flap plane turned into the tube cross section, the valve flap 14 can also be rotated in the valve tube 13 without a buffer as described above. When pulled out of the closed position, the valve flap 14 tilts back to its original position at r = 45 °.

The flexibility of the valve flap 14 can achieve the same effect without the additional configuration of the flap to tilt around the pivot point 142. In this case the area of the valve flap 14 which changes direction in the valve tube 13 is deflected elastically through the rigid valve tube 13, so that the flap plane projected on the tube cross section is likewise reduced. This can be configured such that the valve tube 13 and the valve flap 14 can be tilted as described. The effect described here is supplemented, a very easy to handle and sealingly closed flap valve 10 is formed.

The valve flap 14 and / or the valve tube 13 are made of plastic, thermoplastic, duroh plastics or elastomers, which materials can function as sealing elements in the corresponding geometry. Both parts can also be manufactured in two-component technology. It is also possible to manufacture the valve flap 14 or the valve tube 13 from metal or ceramic.

If the valve flap 14 is made of elastomer, instead of the flexible valve tube 13, a rigid valve tube can be used without increasing the closing moment of the flap valve. This makes it possible for the flexible flap to be provided in at least a nearly elliptical valve flap so that the rigid and flexible thin-walled valve tube can be sealed.

The flap valve 10 described has the advantage of minimizing the risk of mechanical tightening through the described configuration, where variation in the size of the valve flap 14 is less affected through the inclined position with respect to the valve tube 13. Because it's crazy. The bellows tube section 134 of the valve tube 13 also supports the inclination point or inclination of the valve tube 13 and thereby better enclosing the valve flap 14. A mechanical stop for fixing the closed position of the valve flap 14 is not necessary in the case of the flap valve 10 described.

If the demand for the density of the flap valve 10 is low, the outer contour of the valve flap 14 may be selected to be equal to or smaller than the contour of the inner cross section of the tube in the closed region of the valve flap 14 and This is to further reduce the closing moment of the flap valve 10.

The control characteristic curve of the flap valve 10 can be varied by the inclined tube edge 131 being formed at least partially corrugated. In the embodiment of the flap valve 10 shown in FIG. 8, the overall annular tube edge 131 has a waveform. By correspondingly configuring and arranging the ridges and grooves of the tube edge 131, the open, open cross-section of the flap valve 10 is defined through the pivot path of the valve flap 14 or the rotational angle of the flap shaft 15. It can change in a way. Another characteristic curve effect can be reached by relatively rotating the valve tube 13 and the valve flap 14 in the suction tube 10.

The invention is not limited to the described embodiments. Accordingly, the entire valve tube 13 should be able to be formed to be flexible or elastically deformable. This is met when the above configuration of the valve tube 13 is carried out in the closed region of the valve flap 14, the flexible region can extend up to the inclined tube edge 131.

Claims (23)

A valve tube 13 having a controllable tube cross section 135 and guiding gas flow, and an open position and tube section arranged within the valve tube 13 and for maximum opening of the tube section of the valve tube 13. A flap valve for gas flow control, having a valve flap 14 that can pivot between a closed position to cover, wherein the valve flap is rotationally fixed seated on an adjustable flap shaft 15. The tube end of the valve tube 13 is inclined such that the tube edge 131 of the tube end is positioned in a plane extending with respect to the tube axis 132 of the valve tube 13 under an acute angle β, and the flap valve 14 ) Has an outer contour that is at least nearly elliptical, and slopes in the valve tube 13 such that the surface normal 20 of the valve flap 14 forms a flap inclination acute angle α with the tube axis 132. Flap valve, characterized in that it is arranged in the region of the tube end and the valve tube (13) is formed at least partially flexible in at least the region of the inclined tube end. A valve tube 13 having a controllable tube cross section 135 and guiding gas flow, and an open position and tube section arranged within the valve tube 13 and for maximum opening of the tube section of the valve tube 13. A flap valve for gas flow control, having a valve flap 14 that can pivot between a closed position to cover, wherein the valve flap is rotatably seated on an adjustable flap shaft 15. The tube end of the tube 13 is inclined such that the tube edge 131 at the tube end is positioned in a plane extending with respect to the tube axis 132 of the valve tube 13 under an acute angle β, and the flap valve 14 Has an outer contour that is at least nearly elliptical, and the tube inclined within the valve tube 13 such that the surface normal 20 of the valve flap 14 forms a flap slope acute angle α with the tube axis 132. Arranged in the region of the end, the valve tube 13 Flap valves, characterized in that formed able to be tilted with respect to the flap shaft (15) at least in the area of the inclined tube end. A valve tube 13 having a controllable tube cross section 135 and guiding gas flow, and an open position and tube section arranged within the valve tube 13 and for maximum opening of the tube section of the valve tube 13. A flap valve for gas flow control, having a valve flap 14 that can pivot between a closed position to cover, the valve flap being in a flap valve that is fixedly seated on an adjustable flap shaft 15. The tube end of the tube 13 is inclined such that the tube edge 131 at the tube end is positioned in a plane extending with respect to the tube axis 132 of the valve tube 13 under an acute angle β, and the flap valve 14 Has an outer contour that is at least nearly elliptical, and the tube inclined within the valve tube 13 such that the surface normal 20 of the valve flap 14 forms a flap slope acute angle α with the tube axis 132. Arranged in the region of the end, the valve flap 14 The flap valve is formed at least partially flexible. A valve tube 13 having a controllable tube cross section 135 and guiding gas flow, and an open position and tube section arranged within the valve tube 13 and for maximum opening of the tube section of the valve tube 13. A flap valve for gas flow control, having a valve flap 14 that can pivot between a closed position to cover, the valve flap being in a flap valve that is fixedly seated on an adjustable flap shaft 15. The tube end of the tube 13 is inclined such that the tube edge 131 at the tube end is positioned in a plane extending with respect to the tube axis 132 of the valve tube 13 under an acute angle β, and the flap valve 14 Has an outer contour that is at least nearly elliptical, and the tube inclined within the valve tube 13 such that the surface normal 20 of the valve flap 14 forms a flap slope acute angle α with the tube axis 132. Arranged in the region of the end, the valve flap 14 Flap valve, characterized in that it is formed inclined with respect to the flap shaft (15). The flap valve according to claim 1, wherein the flap shaft (15) is inclined with respect to the surface normal (20) of the valve flap (14) under a shaft inclination acute angle (r). 6. Flap valve according to claim 5, characterized in that the shaft (152) of the flap shaft (15) is in line with the tube shaft (132). Flap valve according to any of the preceding claims, characterized in that the valve flap (14) is fixed to the end of the flap shaft (15). 8. Flap valve according to any one of the preceding claims, wherein the flap tilt angle (α) can be freely selected between 1 ° and 89 °. 9. The flap valve according to any one of claims 1 to 8, wherein the tube tilt angle (beta) can be freely selected between 3 and 85 degrees. The flap valve according to any one of claims 1 to 9, wherein the flap tilt angle (α) and the tube tilt angle (β) can be freely selected irrespective of each other. 11. The pivot point 142 of the valve flap 14, designated through the flap shaft 15, is spaced from the inclined tube end and is most effective with respect to the inclined tube end. The widely forward, edge point 143 of the outer contour of the inclined valve flap 14 is the edge point 133 of the widest lying back tube end 131 at all pivot points of the valve flap 14. Flap valve, characterized in that protrudes above. 12. The surface of the valve flip 14 projected onto the inner tube cross section is almost circular because the outer contour of the valve flip 14 matches the valve tube 13. Flap valve, characterized in that the diameter of the circle is deflected no greater than 20% from the inner diameter of the valve tube (13), preferably equal to the inner diameter. 13. Flap valve according to any of the preceding claims, characterized in that the valve flap (14) comprises a convexly swollen edge surface (141) defining an outer contour. 14. Flap valve according to any of the preceding claims, characterized in that the valve tube (13) is formed to be elastically deformable at least in the closed region of the valve flap (14). The flap valve according to claim 1, wherein the valve tube (13) is formed in a thin wall at least in the closed region of the valve flap (14). The flap valve according to any one of claims 1 to 15, wherein the valve tube (13) has an inner diameter that is set between 5 mm and 200 mm and a wall thickness that is set between 0.05 mm and 2 mm. . 17. The valve according to any one of the preceding claims, wherein the valve tube (13) is in the closed region of the valve flap (14) with an inner contour whose dimensions are slightly smaller than the dimension of the outer contour of the valve flap (14). The flap valve having a. 17. The valve tube (13) according to any one of the preceding claims, wherein the valve tube (13) has an inner contour in the closed region of the valve flap (14) whose dimensions are equal to the dimensions of the outer contour of the valve flap (14). Flap valve, characterized in that. 17. The valve tube (13) according to any one of the preceding claims, wherein the valve tube (13) has an inner contour in the closed region of the valve flap (14), the dimension of which is larger than the dimension of the outer contour of the valve flap (14). It has a flap valve. 20. The flap valve according to any one of the preceding claims, wherein the valve tube (13) is bellows corrugated in a tube section (134) opposite the inclined tube end. 21. The flap valve according to any one of the preceding claims, wherein the tube edge (131) of the inclined tube end is at least partially corrugated. The flap valve according to any one of claims 1 to 21, characterized by use as an exhaust gas recirculation valve in an exhaust gas recirculation line of an internal combustion engine. The flap valve according to any one of claims 1 to 21, which is arranged in a supply line of a suction pipe of an internal combustion engine.