SIDE LOAD FREE EGR VALVE ACTUATION

Abstract

The invention relates to a device for converting a rotational motion of a valve element into a translational motion of same with: a valve element bearing-supported such that it is translationally movable along a translation axis, a cam element with a cam curvature, wherein the cam element is rotatable about an axis of rotation, wherein connected with the valve element is a stem by means of which the valve element can be moved translationally along the translation axis and which comprises an engagement element in engagement with the cam curvature, wherein the engagement element is braced from two sides of the cam element by the stem, and wherein, by rotation of the cam element about the axis of rotation, the engagement element is guided along the cam curvature such that the stem executes a translational motion whereby the valve element executes a translational motion.

Claims

1.-11. (canceled)

12. A device for converting a rotational motion of a valve element into a translational motion of same with: a valve element bearing-supported such that it is translationally movable along a translation axis, a cam element with a cam curvature, wherein the cam element is rotatable about an axis of rotation, wherein connected to the valve element is a stem by means of which the valve element can be moved translationally along the translation axis and which comprises an engagement element which is in engagement with the cam curvature, wherein the engagement element is braced from two sides of the cam element through the stem, and wherein by rotation of the cam element about the axis of rotation the engagement element is guided along the cam curvature such that the stem executes a translational motion whereby the valve element executes a translational motion.

13. The device as in claim 12, wherein the cam curvature is implemented within the cam element and penetrates through it.

14. The device as in claim 12, wherein the engagement element extends from one side of the cam element to the opposite side of the cam element and is braced on these two sides by the stem.

15. The device as in claim 12, wherein the axis of rotation of the cam element is spaced apart with respect to the translation axis when viewed along the direction of the axis of rotation of the cam element.

16. The device as in claim 12, wherein the cam element is implemented unitarily with a toothed wheel element which is coupled with a motor such that the cam element can be rotated about the axis of rotation through the motor.

17. The device as in claim 12, wherein the cam curvature has the form of an involute to a circle.

18. The device as in claim 12, wherein the cam curvature has the form of a logarithmic (new) spiral or an Archimedes spiral.

19. The device as in claim 12, wherein the engagement element comprises a roller which is guided on or in the cam curvature, wherein the roller can rotate with respect to the stem.

20. The device as in claim 19, wherein the roller is guided through a shaft wherein at least one end is fixedly connected with the stem.

21. The device as in claim 12, wherein the engagement element is braced by the stem such that a center axis of the stem intersects, parallel to the translation axis, the surface of the cam element through which the cam curvature is formed.

22. An exhaust gas return valve with a device as in claim 12 with a valve seat, wherein the valve element through rotation of the cam element is movable between a contact position, wherein the valve element is in contact on the valve seat, and a clearance position, wherein the valve element is spaced apart from the valve seat.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0034] FIG. 1 is a diagram to illustrate the functional principle of the present invention.

[0035] FIG. 2 is a sectional view through a corresponding device.

[0036] FIG. 2a is a sectional view through the device according to FIG. 2 when used in an exhaust gas return valve.

[0037] FIG. 3 is a sectional diagram of a detail of the device according to FIG. 1.

[0038] FIG. 4 shows a detail corresponding to FIG. 3 according to prior art.

DETAILED DESCRIPTION OF THE FIGURES

[0039] In the following the present invention will be described with reference to FIGS. 1 to 4.

[0040] FIG. 1 is a diagram describing the functional principle of the present invention. A valve element 10, in the present case implemented in two parts of a sealing ring 10″ and a metal bracing plate 10′, is secured on a stem 20. This stem 20 is implemented at its upper end in the form of a Y with two arms 20a. These two arms 20a include between them an engagement element 22 which is rotatably bearing-supported by the arms 20a. In the present case this bearing support is implemented by providing two throughholes and inserting a pin 23a into these throughholes. This pin 23a bearing-supports a roller 23 capable of rotating about the pin 23a. The engagement element 22 engages into the cam curvature 16 of a cam element 14 which, in the present case, is formed by a metal plate. However, it can also be formed by any other plate with correspondingly high rigidity. This cam element 14 is rotatably bearing-supported about an axis of rotation 18. With respect to a translation axis 12 of stem 20, this axis of rotation 18 is spaced apart by a distance a drawn in FIG. 1. When the cam element 14 is swiveled about the axis of rotation 18 the engagement element 22 comes into engagement with several regions of the cam curvature 16 whereby the stem 20 is moved back and forth along the translation axis 12. This leads to the opening and closing of a valve connected with this device.

[0041] The above described distance a, which denotes the offset of stem 20 from the axis of rotation 18 of cam element 14 in the direction of cam curvature 16, together with the above described special forms of the cam curvature 16, namely an involute to a circle, logarithmic or Archimedes spiral, yields the advantage of an, at least regional and/or nearly transverse-force-free, force transmission onto the stem. In this context transverse forces are to be understood forces in the lateral direction according to FIG. 1.

[0042] FIG. 2 shows the device according to FIG. 1 after installation. In addition to the elements of FIG. 1, herein is also shown a motor 26 coupled with a toothed wheel element 27. This toothed wheel element 27 meshes with a toothed wheel element 24. The toothed wheel element 24, in turn, is connected with the cam element 14. Through a rotation of toothed wheel element 24 the cam element 14 is rotated about its axis of rotation 18. As already stated above, this results in the motion of valve element 10. Furthermore is provided a guidance 21 that guides the stem 20. This guidance 21, in the form of a sleeve, is received in a housing 21a. By providing such a guidance, in particular a guidance with low friction coefficient, the stem 20 can be guided securely and at low loss. This avoids a tilting of the stem 20 with respect to the translation axis 12. Thereby that the guidance 21 has only low frictional resistance, friction losses can be avoided.

[0043] FIG. 2a shows FIG. 2 in a different sectional view. This implementation is specifically intended for an exhaust gas return valve 30 that comprises an exhaust gas return port fitting 32. In FIG. 2a the bilateral bracing of the engagement element 22 is clearly visible, which is formed by a pin 23a and a roller 23. The pin 23a is held by arms 20a. In the present case it can also be seen that the cam element 14 is guided by an axle 15 which penetrates through a hole in cam element 14. This axle 15 is rotatably bearing-supported. Further provided is a housing 28, provided on the housing 28a and covering the toothed wheel mechanism.

[0044] The advantages of the present invention are more clearly evident by comparing FIGS. 3 and 4. FIG. 4 shows, as already stated previously, a segment from an exhaust gas return valve of prior art, while FIG. 3 shows a corresponding segment of an exhaust gas return valve according to the invention.

[0045] Through these two arms 20a of stem 20, pin 23a, fitted into these arms 20a, is maintained from both sides of the cam element 14. On this stem 23a [sic] a roller 23 is provided which is rotatable about pin 23a and engages into the cam curvature 16 of cam element 14. The roller 23 is guided through this engagement by the cam element 14, which, as already stated above, leads to the fact that the valve element 10 can move up and down during the swiveling of cam element 14.

[0046] In contrast to FIG. 4, which only shows a one-sided bracing of pin 23a′, pin 23a is braced on both sides of cam element 14. As already stated above, this leads to the avoidance of a bending moment acting onto pin 23a and onto stem 20. This is of advantage in terms of free movement and reliability of the exhaust gas return valve or the device for converting a rotational motion into a translational motion of a valve element (i.e. of an actuator).