Apparatus for the actuation of a throttle valve, in particular a throttle valve of an intake system of an internal combustion engine

Abstract

An apparatus for the actuation of a throttle valve, in particular a throttle valve arranged in an intake system of an internal combustion engine, uses a servomotor, in which apparatus at least one device for thermal decoupling is arranged between the throttle valve and servomotor. A shaft of the servomotor is coupled to a shaft of the throttle valve via a torque-transmitting coupling element with a definedly low heat transfer capability.

Claims

1. An apparatus for the actuation of a throttle valve arranged in an intake system of an internal combustion engine, comprising: a servomotor having a servomotor shaft; at least one device for thermal decoupling arranged between the throttle valve and the servomotor, wherein the device for thermal decoupling comprises a torque-transmitting coupling element coupling the shaft of the servomotor to a throttle valve shaft of the throttle valve, wherein the coupling element has a definedly low heat transfer capability, wherein the coupling element is connected to one of the servomotor shaft and the throttle valve shaft so that the coupling element and the one of the servomotor shaft and the throttle valve shaft are fixedly connected with respect to rotation and axially movable relative to each other; and a mount comprising two L-shaped angle brackets, each of the L-shaped angle brackets having a base and a leg, the bases of the L-shaped angle brackets being connected using threaded connecting elements to form a U-shaped motor support with one of the legs connected to the throttle valve and the other of the legs connected to the servomotor, wherein a distance between the legs is adjustable within a predefined setting range.

2. The apparatus according to claim 1, wherein the coupling element has a lower heat transfer capability than at least one of the servomotor shaft and the throttle valve shaft.

3. The apparatus according to claim 1, wherein the holder mount is open at least on one side, and the coupling element is situated in the holder mount.

4. The apparatus according to claim 3, wherein the holder mount has fastening holes on a side facing toward the servomotor, said fastening holes being designed for the fastening of servomotors with connection flanges of different sizes.

5. The apparatus according to claim 4, wherein the fastening holes are slot-shaped fastening holes.

6. The apparatus according to claim 1, wherein the coupling element is composed at least partially of at least one of ceramic, plastic, or some other material of low thermal conductivity.

7. The apparatus according to claim 1, wherein the coupling element is coupled to one of the throttle valve shaft and the servomotor shaft by linear or punctiform contact surfaces.

8. The apparatus according to claim 1, wherein the coupling element comprises a linkage between the throttle valve shaft and the servomotor shaft.

9. The apparatus according to claim 1, wherein the coupling element is a sleeve having a first side connected to the one of the servomotor shaft and the throttle valve shaft, and a second side connected to the other one of the servomotor shaft and the throttle valve shaft by a clamped connection.

10. The apparatus according to claim 9, wherein the clamped connection of the sleeve-shaped coupling element is effected by a slotted and thus radially adjustable clamping region.

11. The apparatus according to claim 10, wherein the clamping region can be braced by a clamping screw.

12. The apparatus according to claim 9, wherein the coupling element has, on the first side, a receiving opening with a larger diameter than the one of the servomotor shaft and the throttle valve shaft inserted therein, and wherein the one of the servomotor shaft and the throttle valve shaft is connected to the coupling element by way of a transverse pin in one of a longitudinal slot and a longitudinal groove on the coupling element.

13. The apparatus according to claim 3, wherein the mount has a passage opening for the shaft of the servomotor, the opening diameter of the passage opening is dimensioned such that the coupling element can be guided through the passage opening.

14. An internal combustion engine for a motor vehicle or in the form of a static engine, having an intake system through which a hot medium stream flows, wherein an apparatus according to claim 1 is arranged in or on the intake system.

15. The internal combustion engine according to claim 14 wherein the valve is a throttle flap is arranged downstream of a compressor of an exhaust-gas turbocharger of the internal combustion engine and upstream of a charge-air cooler of the intake system.

16. The apparatus according to claim 1, wherein the coupling element is a sleeve having a first side connected to the one of the servomotor shaft and the throttle valve shaft, wherein the one of the servomotor shaft and the throttle valve shaft is connected to the coupling element by way of a transverse pin in one of a longitudinal slot and a longitudinal groove at the first side of the sleeve, the one of the longitudinal slot and the longitudinal groove being open on the first side of the sleeve, such that the transverse pin can be inserted into the one of the longitudinal slot and the longitudinal groove in a longitudinal direction.

17. The apparatus according to claim 1, wherein the mount is open on three sides in an intermediate space between the throttle valve and the servomotor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will be explained in more detail below on the basis of exemplary embodiments illustrated in the drawing, in which:

(2) FIG. 1 is a simplified illustration of an apparatus for actuating a throttle valve,

(3) FIG. 2 shows a view of the apparatus in FIG. 1, but rotated through 90? in relation to FIG. 1,

(4) FIG. 3 shows a perspective view of a coupling element such as is used in the apparatus of FIG. 1 and FIG. 2,

(5) FIG. 4 shows the rear view of the coupling element from FIG. 3,

(6) FIG. 5 shows the plan view of a leg of a U-shaped motor support for the fastening of a servomotor,

(7) FIG. 6a shows a device for actuating a throttle valve, in which device the holder for the servomotor is fastened via spacer sleeves to the housing of the throttle valve,

(8) FIG. 6b shows an exemplary embodiment of the variant shown in FIG. 6a, in a perspective illustration,

(9) FIG. 7 shows the principle of a coupling between servomotor and throttle valve by means of a linkage.

(10) FIG. 8 shows an embodiment of the apparatus for actuating a throttle valve in the form of a cardan joint, and

(11) FIG. 9 shows a schematic diagram of an internal combustion engine including the throttle valve and the device for actuating the throttle valve according to an embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(12) FIG. 1 shows, in simplified form, a throttle valve 1 which is illustrated as a functional block, a servomotor 2, a holder 3, and a coupling element 4 which couples the two shafts 5, 6 of the throttle valve 1 and of the servomotor 2 in torque-transmitting fashion.

(13) The holder 3 is of substantially U-shaped form and is composed of two holding brackets 7, 8 which are screwed to one another by means of screws 9. In the view, rotated through 90?, of FIG. 2, it can be seen that the holding bracket 7 has vertically oriented slots 10, whereby the holding bracket 8 can be adjusted in terms of height relative to the holding bracket 7.

(14) In FIG. 1 and FIG. 2, for the coupling of the two shafts 5, 6, there is provided a coupling element 4 which is in the form of a sleeve and which is fixedly screwed or fixedly clamped to the shaft 6 of the servomotor 2. By contrast, the shaft 5 engages by way of a transverse pin 11 into a longitudinal slot 12 of the clamping element 4. The transverse pin 11 thus forms, in conjunction with the longitudinal slot 12, a positively locking connection by means of which a torque can be transmitted from the coupling element 4 to the shaft 5 of the throttle valve 1.

(15) The coupling element 4 is illustrated in more detail in FIG. 3 and FIG. 4, wherein the transverse pin 11, which engages into the longitudinal slot 12, of the shaft is also indicated in FIG. 3. On the side 13 facing toward the shaft 6 of the servo motor 2, the clamping element 4 has a receiving opening 14 which is matched in terms of diameter to the shaft 6. A slotted clamping region 15 of the clamping element 4 can be clamped by means of a clamping screw 16 to the shaft 6, which is inserted into the receiving opening 14, of the servo motor 2 (FIG. 1) in order to produce a non-positively locking connection between the clamping element 4 and the shaft 6.

(16) In the view of FIG. 4, that side 17 of the clamping element 4 which faces toward the shaft 5 of the throttle valve 1 can be seen in the foreground. The clamping element 4 which is in the form of a sleeve has opposite longitudinal slots 12 into which the shaft 5 of the throttle valve 1 can engage in positively locking fashion by way of transverse pins 11 (FIG. 1) that project from both sides of the shaft. To receive the shaft 5 of the throttle valve 1, the clamping element 4 has a receiving opening 18 which has a considerably larger diameter than the diameter of the shaft 5 to be inserted. It is achieved in this way that, for the shaft 5 of the throttle valve 1, not only is an axial assembly tolerance admissible owing to the longitudinal slots 12, but a small angular deviation relative to the orientation of the shaft 6 of the servomotor 2 is also possible.

(17) The coupling element 4 may be manufactured from a material which has definedly low thermal conductivity. The coupling element 4 may however also be composed of a material of low thermal conductivity only partially, for example in the clamping region of the receiving bore 14 (FIG. 3). As a material with low thermal conductivity, use may for example be made of ceramic or plastic.

(18) To realize low heat transfer between the high-temperature region of the throttle valve and the temperature-sensitive servomotor, there is provided, as per FIG. 1 and FIG. 2, a U-shaped holder 3 which is open on three sides. In this way, the coupling element 4 situated therein can dissipate heat to the ambient air. Furthermore, the U-shaped holder itself also assists in achieving that as little heat as possible is transmitted between the throttle valve 1 and the servomotor 2 via the material of the holder. The open design of the holder 3 specifically also has the effect that the holder 3 in itself can dissipate heat to the environment, thus resulting in only a low thermal load on the servomotor 2.

(19) To increase the stability of the holder 3 as a whole, the two holding brackets 7, 8 may each be equipped with additional narrow side brackets 19, 20 (indicated here by dashed lines), which should however not completely close off the sides of the space in which the coupling element 4 is situated in order that they do not unduly impair the dissipation of heat to the ambient air.

(20) The holding brackets 7, 8 are screwed to one another in each case by way of one leg, whereas the other legs 21, are screwed to the throttle valve 1 and to the servomotor 2. Said legs 21, 22 may have an arrangement of the fastening holes as illustrated in FIG. 5 for the leg 22 of the holding bracket 8. In FIG. 5, the fastening holes 23 are oriented substantially along a diagonal of the leg 22 and are in the form of slots, the slot width of which increases with increasing radial distance from a central passage opening 24. The leg 22 is thus suitable for the fastening of servomotors with connection flanges of different sizes, if the fastening points of the respective servomotor are positioned correspondingly.

(21) In FIG. 5, the passage opening 24 is designed to be relatively small, such that substantially the shaft 6 of the servomotor 2 illustrated in FIG. 1 and FIG. 2 can be guided through said opening. The passage opening 24 may however also, as shown in FIG. 1 and FIG. 2 and also FIG. 6, be designed to be large enough that the clamping element 4 can be guided through the passage opening 24 for assembly purposes.

(22) FIGS. 6a and 6b shows a variant of a holder 33 for the fastening of the servomotor 2 in the region of the throttle valve 1, wherein FIG. 6a shows a schematic diagrammatic sketch, and FIG. 6b shows a perspective illustration, of an exemplary embodiment in this regard. The holder 33 illustrated here has a support plate 25 which is screwed (screws 26a in FIG. 6b) to the housing of the throttle valve 1 via spacer sleeves 26 or through said spacer sleeves. In the case of a rectangular or square support plate 25, it is possible, as schematically illustrated in FIG. 6b, for spacer sleeves 26 to be arranged in each of the corner regions, such that overall, an open receiving space 27 is generated for the clamping element 4, which receiving space ensures very good dissipation of heat from the clamping element 4 to the ambient air. Furthermore, heat conduction to the support plate 25 and thus to the servomotor 2 takes place only to a small extent via the spacer sleeves 26. Such a construction with multiple spacer sleeves 26 arranged in the corner regions is altogether relatively stable, in particular also with regard to the natural frequencies arising in this region.

(23) As can also be gathered very clearly from FIG. 6b, it is the case hereanalogously to the holding bracket 8 of the preceding embodimentthat the support plate 25 forms a holding element of the holder 33, in which holding element the fastening holes 23 for the fastening screws 2a that engage therein are again formed in the manner of elongated holes or slots.

(24) Instead of a sleeve-shaped coupling element, FIG. 7 shows a coupling between the two shafts 5, 6, which in this case are arranged offset with respect one another, via a linkage 28 composed of two actuating rods 29, 30 and a coupling rod 31. Here, the shaft 6 again constitutes the drive shaft of the servomotor 2, which, when it performs a rotational movement in arrow direction 32, causes, via the linkage 28, a rotation of the shaft 5 of the throttle valve in arrow direction 34. A spring element 35, in the form of a tension spring, which engages on the actuating rod 29 of the shaft 5 exerts a return force on the shaft 5 via the actuating rod 29 when the servomotor 2 rotates its shaft 6 in arrow direction 32.

(25) The linkage 28 may be composed of a material of low thermal conductivity. Even in the event of the linkage 28 being formed from metal, an embodiment of a coupling element is obtained which permits only very low heat transfer via the parts that are mechanically coupled to one another.

(26) FIG. 8 shows an embodiment in which the coupling element 4 includes a cardan foist,

(27) FIG. 9 is a schematic diagram of an internal combustion engine 101 having an exhaust 102 connected to a turbo charger 104. A compressor 106 of the turbocharger 104 is arranged in an intake air system 105. The throttle valve 1 with the above-described apparatus for actuating the throttle valve is arranged downstream of the compressor 106 and upstream of a charge-air cooler 108 of the intake air system 105. The throttle valve includes a throttle flap controlling air flow in the intake air system 105.