Mounting of a flap valve shaft

Abstract

The invention relates to a bearing system 1 of a flap valve 6 consisting of a valve shaft 1.1 with a valve shaft pivot 1.2, and consisting of a separate bearing body 2 which is fastened on the end side to the valve shaft 1.1, and of a valve housing wall 3 which has a shaft bearing 3.1 in the form of a depression, the bearing body 2 being guided rotatably in the depression 3.1. Here, the bearing body 2 has a recess 2.1, into which a separate bearing piece 4 is inserted, the valve shaft 1.1 bearing indirectly via the bearing body 2 and the bearing piece 4 against the housing-side shaft bearing 3.1, the bearing body 2 and the bearing piece 4 being formed from different metals or different materials.

Claims

1. A bearing system of a flap valve, comprising: a valve shaft with a valve shaft pivot for a valve flap, a bearing body, and a valve housing wall which has a shaft bearing in the form of a depression, the bearing body being guided at least indirectly in the depression and being rotatable about the valve shaft pivot, said bearing body being adapted to bear at least indirectly against the shaft bearing in an axial direction A with respect to the valve shaft pivot, the bearing body having a recess, into which a bearing piece is inserted, the bearing piece bearing against the shaft bearing, with the result that the bearing body is guided such that it bears indirectly via the bearing piece against the shaft bearing and is rotatable about the valve shaft pivot, wherein the bearing body is fastened on an end side to the valve shaft, the bearing body and the bearing piece are formed from different materials, wherein the bearing body and the valve shaft are connected permanently by brazing or welding.

2. Bearing system according to claim 1, wherein the bearing piece is mounted within the recess of the bearing body and moveable in the axial direction A with respect to the valve shaft pivot, a prestressing element being provided within the recess, the bearing piece being prestressed relative to the bearing body in the axial direction A with respect to the valve shaft pivot via the prestressing element.

3. Bearing system according to claim 1, wherein the bearing piece is fixed within the recess of the bearing body in the axial direction A with respect to the valve shaft pivot.

4. Bearing system according to claim 1, wherein the bearing piece and the bearing body have a positively locking connection which acts in the axial direction A with respect to the valve shaft pivot, the positively locking connection a) being configured as a one-sided stop, against which the bearing piece bears, or b) fixing the bearing piece in the axial direction A with respect to the valve shaft pivot in both directions.

5. Bearing system according to claim 4, wherein the one-sided positively locking connection is configured as a shoulder.

6. Bearing system according to claim 1, wherein at least at operating temperature, the bearing piece being moveable in a circumferential direction U with respect to the valve shaft pivot relative to the bearing body or has a slight play in the radial direction.

7. Bearing system according to claim 1, wherein a cavity is provided within the recess, between the bearing piece and the bearing body, in which cavity lubricant stored.

8. Bearing system according to claim 1, wherein the recess has a beaded edge which forms an undercut and a positively locking connection with the bearing piece in the axial direction A, the bearing piece having a region B1 with a diameter d1 and a region B2 with a diameter d2, where d1>d2, the region B1 bearing against the beaded edge within the recess for the purpose of the formation of the positively locking connection.

9. Bearing system according to claim 7, wherein the bearing piece is of spherical configuration and has a diameter d1, or in that the bearing piece is of pin-shaped configuration and has a shoulder which is arranged within the recess, has the diameter d1, and bears against the edge.

10. Flap valve having a valve housing for connecting to an exhaust gas system and a valve flap with a bearing system according to claim 1.

Description

(1) Further advantages and details of the invention are described in the patent claims and in the description and are shown in the figures, in which:

(2) FIG. 1 shows an outline sketch of a flap valve integrated into an exhaust gas system, and

(3) FIGS. 2-6 show an outline sketch of the detailed view for mounting the valve shaft.

(4) FIG. 1 shows a flap valve 6 which is integrated within an exhaust gas system 8 consisting of two exhaust gas pipes. The flap valve 6 has a valve housing 6.4, within which a valve flap 6.1 with a valve shaft pivot 1.2 is arranged. The valve flap 6.1 is mounted in relation to the valve shaft pivot 1.2 via an upper sleeve bearing or shaft bearing 6.2 and a lower bearing system 1 within the housing 6.4. The valve flap 6.1 is driven via a drive 6.3. The bearing system 1 is formed by way of a bearing body 2 which is connected to the valve shaft 1.1 and/or the valve flap 6.1, and a bearing piece 4 which is arranged therein. The bearing piece 4 is positioned within a depression 3.1 of the valve housing wall 3.

(5) FIG. 2 shows said situation in detail as follows.

(6) The bearing body 2 is connected directly to the valve shaft 1.1 or, in the case of a valve shaft 1.1 which is contained integrally within the valve flap 6.1, to the valve flap 6.1. Material with a comparable or similar coefficient of thermal expansion, in particular metal, comes into consideration both for the shaft 1.1 and/or the flap 6.1 and for the bearing body 2, with the result that welding or brazing of the two components is possible for connecting purposes. The bearing body 2 has a recess 2.1 at the lower end. The bearing piece 4 is arranged within said recess 2.1. According to FIG. 2, the bearing piece 4 is a ball, preferably made from ceramic material, which is mounted within the recess 2.1. In order that the bearing piece 4 does not fall out, the recess 2.1 has an undercut 2.2, with the result that the diameter d2 of the bearing piece 4 is greater than the opening diameter d1 of the recess 2.1. The undercut 2.2 can be provided all the way around, or else only over a part circumference.

(7) In the region of said bearing system 1, the valve housing wall 3 has a depression 3.1 which is configured as a shaft bearing and within which the bearing body 2 comes into contact via the bearing piece 4. The contact takes place, in particular, in the axial direction A. Moreover, the bearing piece 4 is at least guided in the radial direction on account of the trough-shaped form of the depression 3.1. An exact relative movement between the bearing body 2 and the valve housing wall 3 in the circumferential direction U (see FIG. 3) is therefore ensured.

(8) In contrast to the exemplary embodiment of FIG. 2, the exemplary embodiment of FIG. 3 is a bearing piece 4 of cylindrical configuration on one side which is positioned within a corresponding recess 2.1 within the bearing body 2. The bearing piece 4 is flat on its upper side and bears against the bearing body 2 onto a correspondingly flat inner wall 2.5 within the recess 2.1. As an alternative (shown using dashed lines), the bearing piece 4* can also be of spherical configuration on its upper side. This is associated with relatively simple assembly and an optimum pressure distribution in the bearing piece 4* in the case of axial prestress or pressure of the bearing piece 4*. The underside of the bearing piece 4 is of spherical configuration and comes into contact in the axial direction A within the depression 3.1, as is also the case according to the exemplary embodiment of FIG. 2.

(9) According to the exemplary embodiment of FIG. 4, the bearing piece 4 is configured as a ball, as is also the case according to FIG. 2. The recess 2.1 is widened. It extends substantially more deeply into the bearing body 2, with the result that a prestressing element 5 which is configured as a spring is provided between the bearing piece 4 and the inner wall 2.5 of the bearing body 2. The bearing piece 4 is prestressed via the prestressing element 5 or the spring against the undercut 2.2 or the edge 2.4 which is formed in this way. Said prestressing acts in the axial direction A. As long as the bearing piece 4 does not bear against the edge 2.4 of the undercut 2.2 on account of the relative position between the valve shaft 1.1 and the valve housing wall 3, a prestress of the valve shaft 1.1 with respect to the valve housing wall 3 takes place in this case.

(10) A spring 5 is likewise provided in the exemplary embodiment of FIG. 5. In this case, the bearing piece 4 is likewise of cylindrical or piston-shaped configuration. For the purpose of bearing against the edge 2.4 of the undercut 2.2, the bearing piece 4 has a shoulder 4.1 with a diameter d2 which is of greater configuration than an opening cross section d1 of the recess 2.1. The bearing piece 4 consequently has a region B1, the diameter d1 of which is greater than a diameter d2 of a region B2. This applies correspondingly to the bearing pieces 4 according to the exemplary embodiment of FIGS. 2 to 4 and FIG. 6.

(11) As can be seen according to FIG. 6, the bearing piece 4 is once again spherical. The region B1 of the bearing piece 4 has a greater diameter than the region B2, with the result that the bearing piece 4 bears in the region B1 against the edge 2.4 of the undercut 2.2.

(12) In the exemplary embodiments of FIGS. 4, 5 and 6, a cavity 2.3 in the form of a recess 2.1 which is widened in the axial direction A is provided above the bearing piece 4, in which recess 2.1 the spring 5 is provided according to the exemplary embodiment of FIGS. 4 and 5. In all three exemplary embodiments, a lubricant 7 can be stored within said cavity 2.3, as shown in FIG. 6. The lubricant 7 is transported gradually out of the recess 2.1 or the cavity 2.3 on account of the relative movement between the bearing piece 4 and the bearing body 2 and on account of the gap which exists between the bearing piece 4 and the bearing body 2, and ultimately passes into the shaft bearing 3.1 and consequently into the depression at the contact point between the bearing piece 4 and the valve housing wall 3.

(13) According to the exemplary embodiments of FIGS. 4 and 5, the gap between the bearing piece 4 and the edge 2 4 of the bearing body 2 becomes greater, in particular, when the bearing piece 4 is prestressed inward counter to the spring force and, in this case, loses its contact with the edge 2.4 of the undercut 2.2. According to the exemplary embodiments of FIGS. 2, 3 and 6, it is to be determined that the gap which exists between the bearing piece 4 and the bearing body 2 is smallest in the cold state. With increasing heating, in particular at operating temperature, the gap will become considerably greater. This is because the coefficient of thermal expansion of a ceramic component, such as the bearing piece 4 here, is as a rule provided to be lower than that of a metallic component, such as for the bearing body 2 here. At operating temperature, in particular, a sufficient discharge of lubricant 7 from the undercut 2.2 is accordingly ensured.

(14) A radial tolerance compensation is ensured by way of the part-spherical contact between the bearing piece 4, 4* and the bearing body 2, that is to say tolerances in the radial direction can be compensated for by way of an axial feed movement or prestress, with the result that rattling noise is avoided. The part-spherical contact exists on the upper side of the bearing piece 4, 4* according to the exemplary embodiment of FIGS. 2, 3 and 6, and on the underside of the bearing piece 4 according to the exemplary embodiment of FIG. 4, where it bears against the part-spherical undercut 2.4.

LIST OF DESIGNATIONS

(15) Bearing system

(16) 1.1 Valve shaft

(17) 1.2 Valve shaft pivot

(18) 2 Bearing body

(19) 2.1 Recess

(20) 2.2 Undercut

(21) 2.3 Cavity

(22) 2.4 Edge

(23) 2.5 Inner wall

(24) 3 Valve housing wall

(25) 3.1 Depression, shaft bearing

(26) 4 Bearing piece

(27) 4* Bearing piece, alternative shape

(28) 4.1 Shoulder

(29) 5 Prestressing element, spring

(30) 6 Flap valve

(31) 6.1 Valve flap

(32) 6.2 Sleeve bearing, shaft bearing

(33) 6.3 Drive

(34) 6.4 Valve housing

(35) 7 Lubricant

(36) 8 Exhaust gas system

(37) A Axial direction

(38) B1 Region

(39) B2 Region

(40) d1 Diameter, width

(41) d2 Diameter, width

(42) U Circumferential direction