VALVE DEVICE FOR AN INTERNAL COMBUSTION ENGINE

Description

[0001] The invention relates to a flap device for an internal combustion engine with a flow housing, the inner circumferential surface of which defines a flow channel, a rotatably mounted actuating shaft which can be driven by a drive device, a flap body which is arranged on the rotatably mounted actuating shaft in the flow channel, wherein the main extension plane of the flap body is arranged at a distance from the axis of rotation of the actuating shaft.

[0002] Such flap devices are used, for example, as exhaust gas flaps or exhaust gas recirculation valves in low-pressure or high-pressure exhaust circuits and serve to regulate the amount of exhaust gas returned to the cylinders of an internal combustion engine or to regulate the pressure in the exhaust gas recirculation channel to potentially increase the amount of exhaust gas returned, each of which results in a reduction of pollutant emissions from the internal combustion engine. It is also known to use such valves as wastegate valves on the turbine of a turbocharger.

[0003] Such a flap device is disclosed in DE 10 2006 045 420 A1, wherein the flap device comprises a flow housing in which a flow channel is formed. A flap body is arranged in the flow channel, which is attached to an actuating shaft and rotatably mounted in the flow housing via the actuating shaft. The flap body is eccentrically attached to the actuating shaft, with the main plane of extension of the flap body being offset from the axis of rotation of the actuating shaft. The actuating shaft engages with and is driven by an electromechanical actuator.

[0004] A disadvantage of the design shown in DE 10 2006 045 420 A1 is that the eccentric mounting of the flap body to the actuating shaft of the flap body causes increased wear on the inner circumferential surface of the flow housing, thereby reducing the service life of the flap device. In its closed position, the flap body rests against the inner circumferential surface of the flow channel over its entire circumferential outer surface. In the open position and during the pivoting movement between the closed and open positions of the flap body, the contact between the inner circumferential surface of the flow channel and the flap body is largely broken, although the flap body remains in constant contact with the inner circumferential surface in an area surrounding the axis of rotation of the actuating shaft.During the pivoting movement of the flap body, the permanently existing contact between the flap body and the flow housing migrates on the inner circumferential surface of the flow housing, and the repeated pivoting movement of the flap body causes a circular wear surface on the inner circumferential surface.

[0005] From US 2011 / 073789 A1, US 2014 / 238330 A1 and EP 0 424 197 A1, a flap device is known which has a flow housing and an adjustable flap body, wherein the flow housing has a recess which is provided on an inner circumferential surface bounding a flow channel and in the area of ​​the flap body.

[0006] The task is therefore to create a flap device with a flap body eccentrically attached to the actuating shaft, which has reduced wear in the pivoting area of ​​the flap body, thereby increasing the service life of the flap device.

[0007] This problem is solved by a flap device with the features of the main claim. The flow housing has a recess on its inner circumferential surface, the recess being located in the pivoting area of ​​the flap body and spaced apart from a plane defined by the axis of rotation of the actuating shaft and the longitudinal axis of the flow channel. This prevents permanent contact between the flap body and the inner circumferential surface during the pivoting movement of the flap body. The recess creates a radially extending gap between the flap body and the inner circumferential surface in the wear-prone area during the pivoting movement. This reduces wear and increases the service life of the flap device.

[0008] The pocket-like recess has a depth between 0.05 mm and 0.5 mm, whereby the shallow depth of the recess is sufficient to prevent wear and to prevent any negative impact on the flow of the gas flowing through the flow channel.

[0009] Preferably, in its closed position, which completely closes the flow channel, the valve body rests in a sealing position against a sealing area of ​​the inner circumferential surface, with the recess extending axially in the direction of rotation of the valve body to just before the sealing area. This prevents wear, and the flow channel can be completely and fluid-tightly closed in the closed position of the valve body.

[0010] In a preferred embodiment, the recess is provided exclusively in the pivoting area of ​​the flap body. This minimizes the influence on the flow of the gas flowing through the flow channel.

[0011] Preferably, the recess extends from a connecting nozzle to the pivot area of ​​the flap body. This allows the recess to be manufactured simply and cost-effectively. Preferably, the recess is a groove that has a main direction of extension in the direction of the longitudinal axis of the flow channel. In this way, the recess can be manufactured simply and cost-effectively.

[0012] Preferably, the recess has a continuous transition to the inner circumferential surface in the circumferential direction of the flow channel and / or in the flow direction of the flow channel. This prevents a negative influence on the flow of the gas flowing through the flow channel, for example, through undesirable turbulence caused by discontinuous transitions between the inner circumferential surface and the recess.

[0013] Preferably, two recesses, offset tangentially from each other, are provided on the inner circumferential surface. In a preferred embodiment, the first recess is arranged in the region of the upper half of the flap body, and the second recess is arranged in the region of the lower half of the flap body. The wear caused by the eccentric mounting of the flap body occurs in two opposing areas of the inner circumferential surface of the flow housing, adjacent to the actuating shaft. To prevent wear in both areas, a recess is provided in each.

[0014] Preferably, the flow housing is made of plastic. This reduces manufacturing costs and effort. The flow housing can also be made of a fiber-reinforced composite material, in which fibers, for example glass fibers, are embedded in a plastic matrix to improve the mechanical properties of the flow housing.

[0015] In a preferred embodiment, the flow housing is made of polyphenylene sulfide, which is a high-temperature-resistant thermoplastic. This increases the service life of the flow housing, particularly when it is exposed to hot gases, such as exhaust gases from an internal combustion engine. The flow housing made of this high-temperature-resistant plastic can be reliably used at gas temperatures exceeding 200 °C.

[0016] Preferably, the valve body is made of a metallic material, which makes the valve body wear-resistant and temperature-resistant.

[0017] Preferably, the drive device is arranged in a drive housing, wherein the drive housing is integrally formed with the flow housing. This reduces the manufacturing and assembly effort of the flap device.

[0018] In an advantageous embodiment, the actuating shaft is supported on one side, with the actuating shaft projecting into the flow channel through an opening in the flow housing. This one-sided support simplifies the bearing arrangement and increases the service life of the flap device, eliminating the need for a bearing located in the flow channel and subjected to temperature stress from the hot gases, as well as the associated seal.

[0019] Preferably, a thrust washer is provided on the actuating shaft, with the thrust washer being arranged between the flap body and the inner circumferential surface. In a preferred embodiment, the thrust washer rests against the flow housing with one surface facing away from the flap body and against the flap body with one surface facing the flap body. The thrust washer reduces wear on the flow housing in the area of ​​the opening through which the actuating shaft projects into the flow channel, as the flap body bears against the flow housing over a large area, thus preventing the outer edge of the flap body from wearing into the flow housing. Furthermore, the thrust washer improves the seal in the area where the actuating shaft passes through the flow housing.

[0020] Preferably, the thrust washer is fixed to the adjusting shaft in a rotationally fixed manner. This rotationally fixed connection can be achieved by a positive-locking connection, with both the thrust washer and the adjusting shaft having a keyed contour. The positive-locking connection of the thrust washer to the adjusting shaft reduces wear in the area of ​​the opening.

[0021] In a preferred embodiment, the actuating shaft is cylindrical and has a flattened mounting area on its circumferential surface for attaching the valve body. This allows the valve body to be attached to the actuating shaft simply, cost-effectively, and reliably.

[0022] Preferably, the thrust washer is arranged on the adjusting shaft in a rotationally fixed manner via a positive-locking shaft-hub connection, wherein the thrust washer is located on the flattened mounting area, and the cross-section of the shaft-hub connection corresponds to the cross-section of the flattened mounting area of ​​the adjusting shaft. The transmission profile of the shaft-hub connection comprises a circular segment, for example, a circular arc of 200°, and a straight section connecting the two ends of the circular segment. This design of the rotationally fixed connection between the flap body and the adjusting shaft reduces manufacturing effort, since only a single axially extending section of the cylindrical adjusting shaft needs to be produced, particularly by milling, to create the mounting area and the transmission profile of the shaft-hub connection.

[0023] This creates a flap device with an eccentrically mounted flap body, which exhibits no or reduced wear in the pivoting area of ​​the flap body, thereby increasing its service life.

[0024] An embodiment of a flap device according to the invention is shown in the figures and is described below. Figure 1 shows a perspective view of a flap device according to the invention. Figure 2 shows a cross-sectional view of the flow housing and the actuating shaft of the flap device according to the invention. Figure 1 . Figure 3 shows a longitudinal sectional view of the flow housing and the actuating shaft of the flap device according to the invention. Figure 1 . Figure 4 shows a longitudinal sectional view of the flow housing and the flap body in an open position of the flap device according to the invention. Figure 1 . Figure 5shows a longitudinal sectional view of the flow housing and the flap body in a closed position of the flap device according to the invention. Figure 1 .

[0025] The Figure 1 Figure 10 shows a flap device comprising a flow housing 12, which defines a flow channel 14 by means of an inner circumferential surface 11. The free flow cross-section of the flow channel 14 can be controlled by a flap body 16 rotatably arranged in the flow channel 14. The flap body 16 is made of a metallic material and is rigidly connected to an actuating shaft 18 rotatably mounted in the flow housing 12.

[0026] To actuate the adjusting shaft 18, the adjusting shaft 18 is non-rotatably connected at one axial end facing away from the flow channel 14 to a drive device 20. The drive device 20 is arranged in a drive housing 21 and comprises an electric motor and a gearbox interposed between the electric motor and the adjusting shaft 18, the electric motor and gearbox not shown in the figures. The adjusting shaft 18 is rotatably mounted on one side of the drive housing 21 via the section projecting from the flow channel 12.

[0027] The drive housing 21 is manufactured in one piece with the flow housing 12 and is made of a high-temperature-resistant and fiber-reinforced plastic, in particular polyphenylene sulfide. The drive housing 21 has a housing base 22 and a housing cover 24 screwed to the housing base 22, wherein a connector 26 is arranged on the housing cover 24, which is connected to a Figure 1 The circuit board is coupled to the circuit board not shown and is located inside the drive housing 21 and has several connections for the signal and electrical supply lines.

[0028] The Figure 2Figure 1 shows the flow housing 12 and a section of the actuating shaft 18 projecting into the flow housing 12. The actuating shaft 18 has a mounting area 28 for attaching the flap body 16. The mounting area 28 is designed as a flattened area on the circumferential surface of the actuating shaft 18 and has a key contour. The key contour is shown in Figure 3The diagram shows a circular segment with a constant radius, for example, an arc of 200°, and a straight segment. The straight segment extends between the two ends of the circular segment. The flap body 16 rests against the mounting area 28 and is screwed to the actuating shaft 18. For this purpose, the flap body 16 has two through-holes 30, 32, which are offset from each other in the axial direction of the actuating shaft 18. The actuating shaft 18 has two threaded bores 34, 36 in the mounting area 28, corresponding to the through-holes 30, 32. The flap body 16 is fastened to the actuating shaft 18 by two screws 38, 39, which are inserted through the through-holes 30, 32 and screwed into the threaded bores 34, 36.

[0029] A thrust washer 40 is provided at the end of the mounting area 28 facing the drive housing 21. The thrust washer 40 rests against the flap body 16 with its annular surface facing the flap body 16 and against the inner circumferential surface 11 of the flow housing 12 with its annular surface facing the flow housing 12. The thrust washer 40 is rotationally fixed to the actuating shaft 18 via a shaft-hub connection, the thrust washer 40 having an opening 42 corresponding to the cross-section of the mounting area 28, so that the mounting area 28 is simultaneously a component of the shaft-hub connection.

[0030] The thrust washer 40 is arranged in a groove 44 produced on the inner circumferential surface 11 of the flow housing 12, the groove 44 extending axially to a connecting nozzle 45 of the flow housing 12, which facilitates the assembly of the thrust washer 40.

[0031] The thrust washer 40 prevents the metallic flap body 16 from becoming embedded in the plastic flow housing 12 due to wear, while the rotationally fixed connection of the thrust washer 40 to the actuating shaft 18 further reduces wear.

[0032] The Figures 4 and 5Figure 1 shows the flow housing 12, the actuating shaft 18, and the flap body 16. The flap body 16 has a main extension plane 17, which is radially offset from the axis of rotation 15 of the actuating shaft 18, so that the flap body 16 is eccentrically attached to the actuating shaft 18. In its closed position, the eccentrically attached flap body 16 rests against a sealing area 56 of the inner circumferential surface 11 of the flow channel 14 over its entire circumferential outer surface. During the pivoting movement between the closed and open positions, as well as in the open position of the flap body 16, the contact between the inner circumferential surface 11 of the flow channel 14 and the flap body 16 is largely broken, although the flap body 16 remains in permanent contact with the inner circumferential surface 11 in an area surrounding the axis of rotation 15 of the actuating shaft 18.During the pivoting movement of the flap body 16, the permanently existing contact between the flap body 16 and the flow housing 12 migrates along the inner circumferential surface 11 of the flow housing 12, and the repeated pivoting movement of the flap body 16 causes a circular wear surface on the inner circumferential surface 11. Such a wear surface forms in a region of the upper flap half of the flap body 16 adjacent to the actuating shaft 18 and in a region of the lower flap half of the flap body 16 adjacent to the actuating shaft 18.

[0033] To prevent wear, two groove-like recesses 50, 52 are provided on the inner circumferential surface 11, extending axially over a pivoting range 54 of the flap body 16 and to the connecting nozzle 45. The recesses 50, 52 extend in the direction of rotation of the flap body 16 to just before the sealing area 56. The recesses 50, 52 are spaced apart from a plane 19 defined by the axis of rotation 15 of the actuating shaft 18 and a longitudinal axis 13 of the flow channel 14, thus creating the recesses 50, 52 in the area of ​​the wear surfaces. The longitudinal axis of the flow channel 14 need not be, as in the Figures 4 and 5 shown, not necessarily the axis of symmetry of the flow channel 14, but can be offset radially to the axis of symmetry of the flow channel 14 in any way within the flow channel 14.

[0034] The recesses 50 and 52 have a depth of 0.1 mm. Furthermore, the recesses 50 and 52 feature a continuous transition 60 to the inner circumferential surface 11 of the flow housing 12 in the circumferential direction of the flow channel 14, and a continuous transition 62 in the flow direction of the flow channel 14. These continuous transitions 60 and 62 ensure that the flow of the exhaust gases through the flow channel 14 is not negatively affected, for example, by turbulence.

[0035] Due to the recesses 50, 52, a gap forms between the flap body 16 and the flow housing 12 during the pivoting movement of the flap body 16, thus preventing contact between the flap body 16 and the inner circumferential surface 11 of the flow housing 12. In the closed position of the flap body 16, the flap body 16 rests against the inner circumferential surface 11 in the sealing area 56, forming a seal.

[0036] This creates a flap device with an eccentrically mounted flap body, in which wear is reduced in a simple and cost-effective manner by means of two recesses 50, 52 and a thrust washer 40, thereby increasing the service life of the flap device.

[0037] It should be clear that the protected area is not limited to the described embodiment, but that various modifications are conceivable. For example, the flow housing could be made of a different material or the recess could be designed differently.

Claims

1. A flap device for an internal combustion engine with a flow housing (12), the inner circumferential surface (11) of which delimits a flow channel (14), a rotatably mounted actuating shaft (18) which can be driven by a drive device (20), a flap body (16) which is arranged on the rotatably mounted actuating shaft (18) in the flow channel (14), wherein the main extension plane (17) of the flap body (16) is arranged at a distance from the axis of rotation (15) of the actuating shaft (18), wherein the flow housing (12) has a recess (50, 52) on the inner circumferential surface (11), wherein the recess (50, 52) is arranged in the pivot region (54) of the flap body (16) and is arranged at a distance from a plane (19) spanned by the axis of rotation (15) of the actuating shaft (18) and the longitudinal axis (13) of the flow channel (14), characterized in that the recess (50, 52) has a depth of between 0.05 mm and 0.5 mm.

2. The flap device according to Claim 1, characterized in that in its closed position completely closing the flow channel (14), the flap body (16) lies in a sealing manner against a sealing region (56) of the inner circumferential surface (11), wherein the recess (50, 52) extends axially to directly in front of the sealing region (56) in the direction of rotation of the flap body (16).

3. The flap device according to Claim 1 or 2, characterized in that the recess (50, 52) is provided exclusively in the pivot region of the flap body (16).

4. The flap device according to one of the preceding claims, characterized in that the recess (50, 52) extends, starting from a connecting piece (45), to the pivot region (54) of the flap body (16).

5. The flap device according to one of the preceding claims, characterized in that the recess (50, 52) is a groove which has a main extension direction in the direction of the longitudinal axis of the flow channel (14).

6. The flap device according to one of the preceding claims, characterized in that the recess (50, 52) has a continuous transition to the inner circumferential surface (11) in the circumferential direction of the flow channel (14) and / or in the flow direction of the flow channel (14).

7. The flap device according to one of the preceding claims, characterized in that two recesses (50, 52), offset tangentially to one another, are provided on the inner circumferential surface (11).

8. The flap device according to Claim 7, characterized in that the first recess (50) is arranged in the region of an upper half of the flap body (16), and the second recess (52) is arranged in the region of the lower half of the flap body (16).

9. The flap device according to one of the preceding claims, characterized in that the flow housing (12) is made of plastic.

10. The flap device according to Claim 9, characterized in that the flow housing (12) is made of polyphenylene sulphide.

11. The flap device according to one of the preceding claims, characterized in that the flap body (16) is made of a metallic material.

12. The flap device according to one of the preceding claims, characterized in that the drive device (20) is arranged in a drive housing (21), wherein the drive housing (21) is embodied in one piece with the flow housing (12).

13. The flap device according to one of the preceding claims, characterized in that the actuating shaft (18) is mounted on one side, wherein the actuating shaft (18) protrudes into the flow channel (14) through an opening in the flow housing (12).

14. The flap device according to one of the preceding claims, characterized in that a thrust washer (40) is provided on the actuating shaft (18), wherein the thrust washer (40) is arranged between the flap body (16) and the inner circumferential surface (11) of the flow housing (12).

15. The flap device according to Claim 14, characterized in that the thrust washer (40) lies against the flow housing (12) with a surface facing away from the flap body (16) and lies against the flap body (16) with a surface facing the flap body (16).

16. The flap device according to Claim 14 or 15, characterized in that the thrust washer (40) is fastened to the actuating shaft (18) in a rotationally fixed manner.

17. The flap device according to one of the preceding claims, characterized in that the actuating shaft (18) is embodied in a cylindrical manner and has a flattened fastening region (28) produced on the circumferential surface of the actuating shaft (18) for fastening the flap body (16).

18. The flap device according to one of Claims 14, 15 or 16 and Claim 17, characterized in that the thrust washer (40) is arranged in a rotationally fixed manner on the actuating shaft (18) via a form-fitting shaft-hub connection, wherein the thrust washer (40) is arranged on the flattened fastening region (28), wherein the cross-section of the shaft-hub connection corresponds to the cross-section of the flattened fastening region (28) of the actuating shaft (18).