EXHAUST GAS FLAP DRIVE

Abstract

An exhaust gas flap drive for an internal combustion engine, including a driveshaft which has a central axis m, an exhaust gas flap shaft, which is indirectly connected to the driveshaft and has a central axis k, and a coupling element, which is designed as a spring. The coupling element has a first end portion which is rotationally fixed to the driveshaft, and the driveshaft has a receiving area in which the end portion is mounted. The coupling element additionally has a second end portion which is rotationally fixed to the exhaust gas flap shaft via a coupling element, and the receiving area is designed as a groove which is provided on the end face of the driveshaft. The groove has a groove base and two groove flanks which delimit a width b of the groove. The width b decreases towards the groove base, and/or the coupling element has a form-fitting connection with the second end portion in a direction of the central axis k.

Claims

1. An exhaust gas flap drive for an internal combustion machine, comprising: a drive shaft featuring a middle axis m with an exhaust gas flap shaft indirectly connected to the drive shaft and featuring a middle axis k, and with a coupling element designed as a spring, wherein the coupling element has a first end section which is connected to the drive shaft in a torque-proof manner, wherein the drive shaft has a holder in which the first end section is supported, wherein the coupling element also has a second end section which is connected via a coupling member to the exhaust gas flap shaft in a torque-proof manner, wherein the coupling member and the second end section have a form fit in an axial direction to the middle axis k and in a circumferential direction.

2. The exhaust gas flap drive according to claim 1, wherein the coupling member is designed at least partially as a disc with an edge running around the middle axis m, wherein on the edge, at least two or three recesses are provided which run radially, and which serve as a holder for the end section.

3. The exhaust gas flap drive according to claim 2, wherein three recesses are provided, wherein two recesses are arranged diametrically to each other.

4. The exhaust gas flap drive according to claim 2, wherein the disc has a front side and a rear side, wherein the second end section is arranged on the front side and on the rear side.

5. The exhaust gas flap drive according to claim 2, wherein the disc has a radius rs and over a partial circumference U a shoulder which extends in the radial and/or axial direction, with a radius ru, with ru>rs.

6. The exhaust gas flap drive according to claim 2, wherein the second end section has a thickness e, wherein the coupling member and/or the second end section protrudes over the disc in the radial direction to the middle axis k with a maximum degree a of 0<=2m<=e.

7. The exhaust gas flap drive according to claim 1, wherein the holder is designed as a recess in the form of an axially aligned groove or in the form of a radially aligned bore hold, which is provided on the end side on the drive shaft, wherein the groove has a groove base and two groove flanks, which limit a width b of the groove, wherein the width b decreases towards the groove base.

8. The exhaust gas flap drive according to claim 1, with a motor which is connected to the drive shaft, and with an exhaust gas flap which is affixed to the exhaust gas flap shaft and with an exhaust gas flap channel in which the exhaust gas flap is arranged.

9. The exhaust gas flap drive according to claim 8, further including at least a portion of an exhaust gas facility for a motor vehicle.

10. A construction unit for an exhaust gas flap drive according to claim 1, consisting of the coupling element designed as a spring, wherein the coupling element has a first end section which can be connected to the drive shaft of the exhaust gas flap drive, wherein the coupling element additionally has the second end section which can be indirectly connected to the exhaust gas flap shaft, wherein the coupling member is provided which in relation to an axial direction to the middle axis k and in the circumferential direction to the middle axis k is connected in a form and/or force fit manner to the coupling element.

11. A method for mounting an exhaust gas flap drive for an internal combustion machine with a drive shaft featuring a middle axis m with an exhaust gas flap shaft to be indirectly connected to the drive shaft and featuring a middle axis k, and with a coupling element designed as a spring, wherein the coupling element has a first end section which is connected to the drive shaft in a torque-proof manner, wherein the drive shaft has a holder in which the first end section is supported, wherein the coupling element also has a second end section which is connected via a coupling member to the exhaust gas flap shaft in a torque-proof manner, comprising the steps of: a) connecting the coupling member to the exhaust gas flap shaft, and subsequently, connecting the coupling element to the coupling member in an axial direction to the middle axis m and in a form fit manner and with no degree of freedom in a circumferential direction, and subsequently, connecting the coupling element to the drive shaft, or b) connecting the coupling element to the coupling member in the axial direction to the middle axis m and in a form fit manner and with no degree of freedom in the circumferential direction, and subsequently, connecting the coupling member to the exhaust gas flap shaft, or connecting the coupling element to the drive shaft.

12. The method according to patent claim 11, wherein several recesses are provided on the coupling member, and the second end section is clipped in a form fit manner into the recesses.

13. The exhaust gas flap drive according to claim 3, wherein the disc has a front side and a rear side, wherein the second end section is arranged on the front side and on the rear side.

14. The exhaust gas flap drive according to claim 13, wherein the disc has a radius rs and over a partial circumference U a shoulder which extends in the radial and/or axial direction, with a radius ru, with ru>rs.

15. The exhaust gas flap drive according to claim 14, wherein the second end section has a thickness e, wherein the coupling member and/or the second end section protrudes over the disc in the radial direction to the middle axis k with a maximum degree a of 0<=2m<=e.

16. The exhaust gas flap drive according to claim 15, wherein the holder is designed as a recess in the form of an axially aligned groove or in the form of a radially aligned bore hold, which is provided on the end side on the drive shaft, wherein the groove has a groove base and two groove flanks, which limit a width b of the groove, wherein the width b decreases towards the groove base.

17. The exhaust gas flap drive according to claim 16, wherein with a motor which is connected to the drive shaft, and with an exhaust gas flap which is affixed to the exhaust gas flap shaft, and with an exhaust gas flap channel in which the exhaust gas flap is arranged.

18. The exhaust gas flap drive according to claim 17, further including at least a portion of an exhaust gas facility for a motor vehicle.

19. A construction unit for an exhaust gas flap drive according to claim 9, consisting of the coupling element designed as a spring, wherein the coupling element has a first end section which can be connected to the drive shaft of the exhaust gas flap drive, wherein the coupling element additionally has the second end section which can be indirectly connected to the exhaust gas flap shaft, wherein the coupling member is provided which in relation to an axial direction to the middle axis k and in the circumferential direction to the middle axis k is connected in a form and/or force fit manner to the coupling element.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Further advantages and details of the invention are explained in the patent claims and in the description, and demonstrated in the figures, in which:

[0025] FIG. 1 shows a principle sketch of the exhaust gas flap driver with a motor exhaust gas flap and an exhaust gas flap channel in an exploded view;

[0026] FIG. 2 shows the motor drive with a groove;

[0027] FIG. 2b shows the groove profile Q;

[0028] FIG. 3 shows the construction unit consisting of the coupling element and coupling member;

[0029] FIGS. 4a, 4b show the construction unit consisting of the coupling element and coupling member;

[0030] FIGS. 5a-5c show the coupling member.

DETAILED DESCRIPTION OF THE INVENTION

[0031] An exhaust gas flap drive 1 shown in FIG. 1 is a part of an assembly grouping consisting of the motor 5 with a motor shaft 1.1, an exhaust gas flap 1.3 with an exhaust gas flap shaft 1.2 and an exhaust gas flap channel 7, wherein the motor drive 1.1 and the exhaust gas flap shaft 1.2 are connected via an assembly 24 consisting of a coupling element 2 and a coupling member 4.

[0032] The exhaust gas flap 1.3 with the exhaust gas flap shaft 1.2 is arranged in the exhaust gas flap channel 7. The assembly 24 sits on the exhaust gas flap shaft 1.2 which forms the torque connection between the exhaust gas flap shaft 1.2 and the drive shaft 1.1. The motor 5 is indirectly supported via a holder 6 on the exhaust gas flap channel 7. The recess 6 has two arms 6.1, 6.2, which are affixed to the exhaust gas flap channel 7. The arm 6.2 forms a stop for the coupling member 4 or a shoulder 4.2 of the coupling member 4 in the “open” position of the exhaust gas flap 1.3. The stop of the exhaust gas flap 1.3 in the “closed” position is formed by the exhaust gas flap channel 7 itself. According to FIG. 1, the exhaust gas flap 1.3 is located in an interim position between the “open” and “closed” positions, so that the shoulder 4.2 does not lie in contact with the arm 6.2.

[0033] The coupling element 2 is designed as a conical spring and is coupled via a first end section E1 to the motor drive 1.1 and via a second end section E2 to the coupling member 4. For the purpose of coupling the coupling element 2 to the motor drive 1.1, the motor shaft has a groove 3, which has a trapezoid profile Q according to FIG. 2a, 2b. Through the insertion of the coupling element 2 with the end section E1 into the groove 3 and due to the axial pre-tension of the coupling element 2 that is created by the assembly, a force fit coupling occurs between the motor shaft 1.1 and the coupling element 2. The coupling element 2 is also connected to the coupling member 4 in a form fit manner. This is described in greater detail with reference to FIGS. 4a, 4b.

[0034] The trapezoid profile Q of the groove 3 according to FIGS. 2a, 2b guarantees a decreasing width b of the groove 3 towards a groove base 3.1. The two groove flanks 3.2, 3.3 of the groove 3 are accordingly pitched in relation to a middle axis m of the motor shaft 1.1 with a pitching angle of approximately 3°. In general, it would also be sufficient when only one groove flank 3.2, 3.3 were to be pitched differently to a trapezoid profile Q in order to guarantee said tapering of the groove 3. The width b, b′ of the groove 3 varies and decreases, as described, towards the groove base 3.1. According to FIG. 2b, the profile Q is trapezoid. Alternatively, a tapering profile with a profile form that deviates from the trapezoid can also be used.

[0035] According to FIG. 3, the assembly consisting of the coupling element 2 and the coupling member 4 is affixed on the motor shaft 1.1 through the axial insertion of the end section E1 into the groove 3 of the motor shaft 1.1. Thus, the motor shaft 1.1 or a middle axis m and the exhaust gas flap shaft 1.2 to be inserted into the coupling member 4 or a middle axis k are aligned coaxially to each other.

[0036] FIGS. 4a, 4b show the assembly 24, consisting of the coupling element 2 and coupling member 4 alone. The end section E1 limits the coupling element 2 upwards and is bent inwards in a radial direction, starting from the conical basic form of the coupling element 2. The end section E2 is designed in a somewhat more complex manner. Starting from the spiral or conical basic form of the coupling element 2, different bends are provided in order to mold the end section E2 to the coupling member 4. According to FIGS. 5a, 5b, the coupling member 4 has three slits 4a to 4c, wherein the slits 4a, 4b are diametrically arranged. Additionally, a third slit 4c is provided, within which the coupling element 2 is guided back onto a front side 4v, starting from a rear side 4r. The coupling member 4 is basically designed as a disc form, and has a shoulder 4.2 which protrudes in both the radial direction and in the axial direction over the disc-shaped basic form. The disc 4 has a base radius rs, while the should 4.2 has a radius ru that is extended beyond it. The slits 4a to 4c are provided in the area of a fine edge 4.1 of the disc 4. In the center, a bore hole or a hole 4.3 for holding the exhaust gas flap shaft 1.2 is provided. The coupling element 2 has a U-shaped part of the end section E2, into which the disc 4 is inserted in the radial direction until the coupling element 2 latches in both slits 4a, 4b. In conjunction with this, the coupling element 2 further latches in the slit 4c, so that the end section E2, starting from its free end in the area of the rear side 4r of the disc 4, is guided through the slit 4a onto the front side 4v and from there diametrically around the hole 4.3 through to the slit 4b. Further, the end section E2 is guided through the slit 4b onto the rear side 4r of the disc 4 and in turn over the slit 4c onto the front side 4v, and from there, moves into the spiral or conical basic form.

[0037] According to FIG. 5c, the coupling element 2 or the end section E2 guided through the slits 4a to 4c protrudes in the radial direction over the disc 4 by a maximum degree a. According to FIG. 5c, in the area of the slit 4a, the degree is a=0, while in the area of the slit 4c, the degree is a>0. The degree a should not reach the maximum e/2 for guaranteeing a firm seat, however. The shoulder 4.2 protrudes over the edge 4.1 in the radial direction. It guarantees an end stop on the stop 6.2 of the holder 6, and therefore the end stop of the exhaust gas flap 1.3 in the “open” position. Via the motor 5 and the spring 2, an adjustment torque is transferred onto the exhaust gas flap shaft 1.2. Since an adjustment path of the exhaust gas flap shaft 1.2 is not recorded, it is necessary to design the adjustment torque to be sufficiently large, and therefore to render the angle of rotation of the motor 5 or drive shaft 1.1 sufficiently large so that via the spring torque thus generated, the respective end stop of the exhaust gas flap 1.3 or of the exhaust gas flap shaft 1.2 is achieved.