Flap device for an internal combustion engine

Abstract

The invention relates to a flap device for a fuel cell system, comprising a flow housing (12) which delimits at least one flow channel (14), a flap shaft (16) which protrudes into the flow channel (14) and can be rotated about a longitudinal axis (32) between multiple positions by means of an actuator (20), and a flap body (22) which is arranged in the flow channel (14) and to which the flap shaft (16) is secured, wherein the flap body (22) together with the flap shaft (16) can be adjusted at least between a closed position and an open position, and a tolerance compensating element (50, 52) is provided. When the flap device is installed, the tolerance compensating element (50, 52) can be secured to different positions on the flap shaft (16) in order to bridge a gap (53) between the flap shaft (16) and the flap body (22) transversely to the longitudinal axis (32) of the flap shaft (16), said flap body (22) resting against the tolerance compensating element (50, 52) transversely to the longitudinal axis (32), or the tolerance compensating element (50, 52) can be secured to different positions on the flap body (22) in order to bridge a gap (53) between the flap shaft (16) and the flap body (22) transversely to the longitudinal axis (32) of the flap shaft (16), said flap shaft (16) resting against the tolerance compensating element (50, 52) transversely to the longitudinal axis (32).

Description

[0001] DESCRIPTION

[0002] Flap device for an internal combustion engine

[0003] The invention relates to a flap device for a fuel cell system, comprising a flow housing which delimits at least one flow channel, a flap shaft which projects into the flow channel and is rotatable about a longitudinal axis by an actuator between a plurality of positions, and a flap body which is arranged in the flow channel and is fastened to the flap shaft, wherein the flap body is adjustable together with the flap shaft at least between a closed position and an open position.

[0004] Such flap devices are known in particular in connection with internal combustion engines, wherein the flap devices are arranged on an exhaust tract emanating from the internal combustion engine and are used, for example, as exhaust gas dam flaps or as exhaust gas recirculation valves in low-pressure or high-pressure exhaust circuits. Otherwise, such flap devices are used in an air intake duct of the internal combustion engine, in particular as a throttle valve. Such a flap device is disclosed, for example, in EP 3 379 070 A1. The flap devices usually have a flap shaft and a flap body, wherein the flap shaft projects into a flow housing and the flap body fastened to the flap shaft is arranged in the flow housing, i.e. within a flow duct delimited by the flow housing.The valve shaft and the valve body can be adjusted or rotated by an actuator, in particular an electric actuator, between at least one open position and one closed position. In the open position, a flow cross-section of the flow channel is open for a fluid, in this case air or exhaust gas. In the closed position, the flow cross-section of the flow channel is closed by the valve body, with the valve body resting with a sealing surface against a counter-sealing surface formed on the flow housing.

[0005] Furthermore, such flap devices are known in the field of fuel cell systems, where the flap devices serve to control the air flow into the cathode chamber. In this case, the tightness of the flap device in a closed position, i.e., the complete shutoff of the air, is particularly important. Such a flap device is disclosed, for example, in DE 102 04 787 A1.

[0006] The valve shaft of the valve device is usually rotatably mounted on the flow housing, whereby the position of the sealing surface of the valve body in the closed position is rigidly defined by the position of the valve shaft. The corresponding counter sealing surface is usually formed on the flow housing and is therefore also rigidly specified. Manufacturing and assembly tolerances occur in all areas of application of the valve device. These manufacturing and assembly tolerances, particularly in the area of ​​the bearing of the valve shaft, the attachment of the valve body to the valve shaft and the counter sealing surface, can lead to the sealing surface and counter sealing surface being spaced apart from one another in the closed position of the valve device, i.e. not lying tightly against one another, thus causing a high, undesirable leakage flow.

[0007] The object is therefore to provide a flap device that can reduce leakage in the closed position of the flap device. This object is achieved by a flap device having the features of claim 1.

[0008] By providing a tolerance compensation element, wherein during assembly of the flap device the tolerance compensation element can be fastened to the flap shaft in different positions to bridge a gap between the flap shaft and the flap body transversely to the longitudinal axis of the flap shaft, wherein the flap body rests against the tolerance compensation element transversely to the longitudinal axis, or by the tolerance compensation element can be fastened to the flap body in different positions to bridge a gap between the flap shaft and the flap body transversely to the longitudinal axis of the flap shaft, wherein the flap shaft rests against the tolerance compensation element transversely to the longitudinal axis, the manufacturing and assembly tolerances can be compensated in a simple manner and a leakage flow in the closed position of the flap body can be reduced or completely avoided.During the assembly process, the tolerance compensation element can be individually adjusted for each individual flap device, thus reliably compensating for the manufacturing and assembly tolerances that vary between the individual flap devices.

[0009] By adjusting the tolerance compensation element, the sealing surface of the valve body can be displaced transversely to the longitudinal axis of the valve shaft until the sealing surface rests against the counter sealing surface.

[0010] Preferably, the tolerance compensation element has a thread, and the valve shaft or the valve body has a mating thread complementary to the thread, such that the tolerance compensation element can be adjusted by a rotational movement about a longitudinal axis of the tolerance compensation element. This allows the tolerance compensation element to be adjusted simply by twisting, i.e., displaced in both directions depending on the direction of rotation.

[0011] In a preferred embodiment, the tolerance compensation element is sleeve-like and arranged in a through-opening of the valve shaft or the valve body. The tolerance compensation element has an external thread on an outer peripheral surface and an internal thread complementary to the external thread is provided on a peripheral surface of the through-opening. Alternatively, the sleeve-like tolerance compensation element is arranged on a projection of the valve body or the valve shaft. The tolerance compensation element has an internal thread and an internal thread complementary to the external thread is provided on the projection. This allows the tolerance compensation element to be arranged simply and cost-effectively on the valve body or the valve shaft.

[0012] Alternatively, the sleeve-like tolerance compensation element is arranged on a projection or in a through-opening of the flap body or the flap shaft in such a way that the tolerance compensation element is positioned in a position bridging the gap and is welded or glued to the flap body or the flap shaft. A further alternative is that the tolerance compensation element is fastened, in particular screwed, to the flap body and is welded or glued to the flap shaft, or the tolerance compensation element is fastened, in particular screwed, to the flap shaft and is welded or glued to the flap body in such a way that the tolerance compensation element is positioned in a position bridging the gap and is welded or glued to the flap body or the flap shaft.With these two alternatives, the tolerance compensation element can also be arranged easily and cost-effectively on the valve body or the valve shaft.

[0013] Preferably, the fastening means is a screw element, wherein the screw element is arranged coaxially with the sleeve-like tolerance compensation element. When mounted, the screw element extends through the sleeve-like tolerance compensation element. If the tolerance compensation element is arranged, for example, in a through-hole of the valve shaft, the valve body rests against an annular contact surface of the tolerance compensation element screwed into the valve shaft. The valve body is fastened to the valve shaft via the screw element, which bears against the valve shaft with a screw head and is screwed into the valve body.By screwing in the screw element, the valve body is pressed against the circular ring-like contact surface of the tolerance compensation element, whereby before the screw element is tightened, the circular ring-like contact surface is displaced transversely to the longitudinal axis of the valve shaft by adjusting the tolerance compensation element in such a way that in the closed position of the valve body the sealing surface lies sealingly against the counter sealing surface.

[0014] The valve body preferably has a sealing element arranged on the sealing surface. In the closed position, the valve body rests against a counter-sealing surface provided on the flow housing via the sealing surface. In a preferred embodiment, the sealing element is made of a flexible material, in particular an elastomer. This improves the tightness of the valve body in the closed position, with the sealing element elastically deforming upon contact with the counter-sealing surface and thus conforming particularly well to the counter-sealing surface.

[0015] Preferably, a center plane of the valve body is spaced apart from a longitudinal axis of the valve shaft, whereby the valve body is arranged eccentrically on the valve shaft. In a particularly preferred embodiment, a longitudinal axis of the valve body is additionally spaced apart from a transverse axis of the valve shaft, whereby the valve body is attached to the valve shaft in a double-eccentric manner. This reduces the possibility of the sealing surface sliding off the counter-sealing surface during the adjustment process.

[0016] The object is also achieved by a method for assembling a flap device according to one of claims 1 to 9. The method comprises the following steps:

[0017] - Placement of the sealing surface of the valve body against the counter sealing surface of the flow housing,

[0018] - Mounting the valve shaft to the flow housing,

[0019] - Adjusting the tolerance compensation element mounted on the valve body until the tolerance compensation element rests against the valve shaft or adjusting the tolerance compensation element mounted on the valve shaft until the tolerance compensation element rests against the valve body,

[0020] - Fasten the valve body to the valve shaft using the fastener.

[0021] This provides a flap device in which manufacturing and assembly tolerances can be easily compensated and leakage flow in the closed position of the flap body can be reliably reduced or completely avoided. An embodiment of a flap device according to the invention is illustrated in the figures and described below.

[0022] Figure 1 shows a longitudinal section of a flap device, and.

[0023] Figure 2 shows a cross-section of the flap device from Figure 1.

[0024] Figures 1 and 2 show a flap device 10 for a fuel cell system of a motor vehicle, wherein such a flap device 10 serves to control an air volume flow or a hydrogen volume flow.

[0025] The flap device 10 comprises a flow housing 12, which defines a flow channel 14. A flap shaft 16 projects into the flow channel 14 through an opening 18 formed in the flow housing 12. The flap shaft 16 is rotatably mounted on the flow housing 12, with an actuator 20 connected in a torque-transmitting manner to an end of the flap shaft 16 protruding from the flow housing 12, whereby the flap shaft 16 can be adjusted in the direction of rotation by the actuator 20. In the present case, the flap shaft 16 is mounted on one side of the flow housing 12. Alternatively, the flap shaft 16 can also be mounted on both sides of the flow housing 12.

[0026] A flap body 22 is attached to a section of the flap shaft 16 arranged in the flow channel 14. The flap body 22 is double-eccentric. On the one hand, a flap plane 30 is arranged at a distance from a longitudinal axis 32 of the flap shaft 16. On the other hand, a longitudinal axis 34 of the flap body 22 is arranged at a distance from a transverse axis 36 of the flap shaft 16, which is aligned in the direction of the longitudinal axis 34. The flap body 22 is adjustable, together with the flap shaft 16 and by the actuator 20, at least between an open position and a closed position. In the open position, the flow channel 14 is open and not blocked by the flap body 22. In the closed position, the flap body 22 bears sealingly against a conical counter-sealing surface 28 provided on the flow housing 12 with a conical sealing surface 24, on which a sealing element 26 made of an elastomer is arranged.Thus, the flow channel 14 is closed by the valve body 22 in the closed position.

[0027] In order to ensure the tightness between the sealing surface 24 and the counter sealing surface 28 in the closed state of the valve body 22, the valve body 22 is positioned relative to the valve shaft 16 by means of tolerance compensation elements 50, 52. The valve shaft 16 has two through openings 43, 45, in each of which a

[0028] Tolerance compensation element 50, 52 is arranged. The

[0029] Through openings 43, 45 point at the respective

[0030] Each inner circumferential surface has an internal thread 54, 58. The tolerance compensation elements 50, 52 each have an external thread 56, 60 complementary to the respective internal thread 54, 58, so that the tolerance compensation elements 50, 52 can be screwed into the through openings 43, 45. The tolerance compensation elements 50, 52 protrude from the through openings 43, 45 on a side facing the valve body 22 and form an annular contact surface 62, 66 against which the valve body 22 rests in the finally assembled state.

[0031] The tolerance compensation elements 50, 52 are sleeve-like, with a fastening means 40, 44 designed as a screw element 42, 46 extending through the through-openings 43, 45 and through the sleeve-like tolerance compensation elements 50, 52 and being screwed into the flap body 22. For this purpose, the flap body 22 has a projection 70, 72 with an internal thread 71, 73. The projections serve in particular for the eccentric fastening of the flap body 22 to the flap shaft 16, with the flap body 22 resting against a circular ring-like contact surface 62, 66 of the tolerance compensation elements 50, 52 via the free ends of the projections 70, 72.

[0032] During the assembly process of the flap device 10, the flap shaft 16 is first mounted and the flap body 22 is positioned by the sealing surface 24 being in contact with the counter sealing surface 28. Subsequently, the tolerance compensation elements 50, 52 are screwed into the through openings 43, 45 until the end of the

[0033] Tolerance compensation elements 50, 52 with the annular contact surfaces 62, 66 rest on the projections 70, 72 of the valve body 22 and a gap 53 between the valve shaft 16 and the valve body 22 is bridged. As a result, the valve body 22 is clamped between the counter sealing surface 28 and the tolerance compensation elements 50, 52. Finally, the screw elements 42, 46 are inserted through the through holes 43, 45 and the sleeve-like

[0034] Tolerance compensation elements 50, 52 are pushed through and into the

[0035] Valve body 22 screwed in.

[0036] Such a design of the flap device makes it possible to ensure tightness in the closed position of the flap body in a simple and cost-effective manner, whereby the tolerance compensation element can be individually adjusted for each flap device, thus reliably compensating for the manufacturing and assembly tolerances of each individual flap device. It should be clear that the scope of protection of the main claim is not limited to the described embodiment, but various modifications are possible. In particular, the tolerance compensation elements can also be adjustably arranged on the flap body, and the flap shaft can bear against the tolerance compensation elements transversely to the longitudinal axis of the flap shaft. The tolerance compensation elements can also be arranged on a projection instead of in a through-opening, with the tolerance compensation elements being screwed onto the projections.Furthermore, instead of a screw connection, the tolerance compensation element can be designed and mounted in such a way that the tolerance compensation element is positioned in a position bridging the gap between the valve body and the valve shaft and is welded to the valve body or the valve shaft. Furthermore, the tolerance compensation element could be rigidly attached to the valve body and welded or bonded to the valve shaft, such that the tolerance compensation element is positioned in a position bridging the gap and is welded or bonded to the valve body or the valve shaft.Similarly, the tolerance compensation element could be rigidly attached to the valve shaft and welded or glued to the valve body, whereby the tolerance compensation element is also positioned in a gap-bridging position and is welded or glued to the valve body or the valve shaft.

Claims

PATENT CLAIMS A flap device for a fuel cell system, comprising a flow housing (12) which delimits at least one flow channel (14), a flap shaft (16) which projects into the flow channel (14) and is rotatable between several positions about a longitudinal axis (32) by an actuator (20), and a flap body (22) which is arranged in the flow channel (14) and is attached to the flap shaft (16), wherein the flap body (22) together with the flap shaft (16) is adjustable at least between a closed position and an open position, characterized in that a tolerance compensation element (50, 52) is provided, wherein, during assembly of the flap device, the tolerance compensation element (50, 52) is positioned in different locations on the flap shaft to bridge a gap (53) between the flap shaft (16) and the flap body (22) transversely to the longitudinal axis (32) of the flap shaft (16). (16) can be attached,wherein the flap body (22) bears against the tolerance compensation element (50, 52) transversely to the longitudinal axis (32), or the tolerance compensation element (50, 52) can be attached to the flap body (22) in different positions transversely to the longitudinal axis (32) of the flap shaft (16) to bridge a gap (53) between the flap shaft (16) and the flap body (22), wherein the flap shaft (16) bears against the tolerance compensation element (50, 52) transversely to the longitudinal axis (32). Flap device according to claim 1, characterized in that, the tolerance compensation element (50, 52) has a thread (56, 60) and the flap shaft (16) or the flap body (22) has a counter thread (54, 58) complementary to the thread (56, 60), such that the tolerance compensation element (50, 52) is adjustable by a rotational movement about a longitudinal axis of the tolerance compensation element (50, 52). Flap device according to claim 2, characterized in that the tolerance compensation element (50, 52) is designed in a sleeve-like manner and is arranged in a through-opening (43, 45) of the flap shaft (16) or the flap body (22), wherein the tolerance compensation element (50, 52) has an external thread (56, 60) on an outer circumferential surface and an internal thread (54, 58) complementary to the external thread (56, 60) is provided on a circumferential surface of the through-opening (43, 45).A flap device according to claim 2, characterized in that the tolerance compensation element (50, 52) is designed in a sleeve-like manner and is arranged on a projection (70, 72) of the flap body (22) or the flap shaft (16), wherein the tolerance compensation element (50, 52) has an internal thread and an external thread complementary to the internal thread is provided on the projection (70, 72). A flap device according to claim 1, characterized in that the tolerance compensation element (50, 52) is designed in a sleeve-like manner and is arranged on a projection (70, 72) or in a through-opening (43, 45) of the flap body (22) or the flap shaft (16). The tolerance compensation element (50, 52) is arranged such that it is positioned in a position bridging the gap (53) and is welded or bonded to the flap body (22) or the flap shaft (16). The flap device according to claim 3, 4 or 5 is characterized in that the fastening means (40, 44) is a screw element (42, 46), wherein the screw element (42, 46) is arranged coaxially to the sleeve-like tolerance compensation element (50, 52).A flap device according to claim 1, characterized in that the tolerance compensation element (50, 52) is attached to the flap body (22) and is welded or bonded to the flap shaft (16), or the tolerance compensation element (50, 52) is attached to the flap shaft (16) and is welded or bonded to the flap body (22) such that the tolerance compensation element (50, 52) is positioned in a position bridging the gap (53) and is welded or bonded to the flap body (22) or the flap shaft (16). A flap device according to any of the preceding claims, characterized in that the flap body (22) has a sealing element (26) which is arranged on a sealing surface (24), wherein the flap body (22) in the closed position bears against a counter-sealing surface (28) provided on the flow housing (12) via the sealing surface (24). Flap device according to claim 8, characterized in that. The sealing element (26) is made of a flexible material, in particular an elastomer. A flap device according to one of the preceding claims, characterized in that a central plane (30) of the flap body (22) is arranged at a distance from a longitudinal axis (32) of the flap shaft (16). A flap device according to one of the preceding claims, characterized in that a longitudinal axis (34) of the flap body (22) is arranged at a distance from a transverse axis (36) of the flap shaft (16). A method for assembling a flap device (10) according to one of claims 1 to 11, comprising the following steps: - Applying a sealing surface (24) of the flap body (16) to a counter-sealing surface (28) of the flow housing (12), - Mounting the flap shaft to the flow housing, - Relocating the component mounted on the valve body (22) Tolerance compensation element (50, 52) until the Tolerance compensation element (50, 52) rests against the flap shaft (16) or displacement of the tolerance compensation element (50, 52) mounted on the flap shaft (16) until the Tolerance compensation element (50, 52) rests against the valve body (22), - Attaching the flap body (22) to the flap shaft (16).

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