JP2007002846A - Actuator used for actuating mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an actuator capable of attenuating high torque requested from the reason of sealing performance at an abutting position of an actuating mechanism. <P>SOLUTION: A slip clutch 42 is arranged in a force power path between a driven shaft 46 and an actuating mechanism. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  INDUSTRIAL APPLICABILITY The present invention is used for an operating mechanism that travels toward a stopper, in particular, a throttle body that is disposed in a passage for guiding a gaseous medium in an internal combustion engine and that can contact a seal seat so that power is transmitted. An electric actuator having a driven shaft, an operating shaft coupled to an operating mechanism, a driven shaft of the operating motor, and a transmission device disposed between the operating shafts are provided. Is in the form of

  A known electrical actuator for use in the throttle body (see German Offenlegungsschrift DE 10245193) is incorporated in the actuation unit together with the throttle body. The operating unit has an actuator housing. This actuator housing is referred to as a throttle valve tube piece or an exhaust gas recirculation valve, depending on the use associated with the automotive internal combustion engine. A passage extends through the throttle valve pipe piece or the exhaust gas recirculation valve. In this passage, for example, fresh inflowing air or fuel / air mixture or exhaust gas or part of the exhaust gas flows towards or away from the internal combustion engine. The actuator has an electric operating motor. The operating motor drives an operating shaft that supports the throttle body via a two-stage transmission having a non-linear transmission output stage. The transmission device input stage includes a motor pinion that is mounted on the driven shaft of the operating motor so as not to be relatively rotatable, and an intermediate gear that meshes with the motor pinion. The intermediate gear is attached to a transmission shaft fixed in the housing so as to be relatively rotatable. The non-linear transmission output stage has a drive segment and a driven segment that meshes with the drive segment. The drive segment is mounted on the transmission shaft and is coupled to the driven gear of the transmission input stage so as not to be relatively rotatable. The driven segment is mounted on the operating shaft so as not to be relatively rotatable. The operating shaft is pivotally supported in the actuator housing. Both segments of the non-linear transmission output stage mesh with each other via a pitch curve. The pitch curve radius of this pitch curve always changes over the rotation angle. In this case, the pitch curve radius is formed so as to change complementarily when both segments rotate. The non-linear transmission output stage changes the transmission gear ratio between the actuating motor and the throttle body over the adjustment stroke. This has the advantage that the higher torque required for the defined pivot position of the throttle body is provided by a relatively weak output operating motor. Furthermore, different operating speeds can be obtained for the throttle body within the defined adjustment stroke range.

Such electrical actuators or regulators or actuators are also used for bypass regulation in exhaust gas turbochargers used for supercharging diesel engines (Bosch "Kraftfahrtechnisches Taschenbuch" (ISBN 3-528-23877- 3, page 532 and below)). The throttle body is formed as a bypass valve. The bypass valve is applied to a stopper formed by a seal seat in a closed position for closing the bypass. For reasons of bypass sealing in the closed position of the bypass valve, the actuator must apply a high closing force to the throttle valve, which causes the bypass valve to travel to the stopper with high torque.
German Patent Application No. 10245193

  An object of the present invention is to improve an actuator used for an operating mechanism of the type described at the beginning so that a high torque required for the reason of a sealing property at a contact position of the operating mechanism is attenuated. That is.

  In order to solve this problem, in the configuration of the present invention, the slip clutch is arranged in the force transmission path between the driven shaft and the operating mechanism.

  In the actuator according to the present invention having the features of claim 1, the high torque required for sealing performance at the contact position of the operating mechanism is attenuated by the slip clutch when the operating mechanism contacts the stopper. This has the advantage that damage to the actuator is avoided over time. The force with which the actuating mechanism abuts against the stopper is limited to a maximum value by a defined slip in the slip clutch, irrespective of the dynamic operating state of the actuator.

  By means of the different claims, advantageous configurations and modifications of the actuator according to claim 1 are possible.

  According to an advantageous configuration of the invention, a slip clutch is arranged in the transmission. This has the advantage that the slip clutch can be easily assembled and protected against dirt.

  According to an advantageous configuration of the invention, the transmission has a gear pair mounted on the transmission shaft so as to be capable of relative rotation, and the gear pair cannot be rotated relative to each other via the slip clutch. The two clutches are connected, and the slip clutch is realized by means of an axial frictional connection of the gears via the end faces facing each other. In this configuration of the slip clutch, the maximum force that the operating mechanism travels to the stopper can be defined by adjusting the static friction force between the two gears.

  In the following, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  The electrical actuator 30 or actuator shown in longitudinal section in FIG. 1 is advantageously used for supercharging of spark ignition engines and diesel engines, such as an exhaust gas turbocharger 10 as partially shown in FIG. Used for bypass adjustment in Such an exhaust gas turbocharger 10 includes two fluid machines, that is, a turbine 11 and a compressor 12. Both fluid machines are arranged on a common shaft 13. The turbine 11 has a turbine wheel 15 disposed in the turbine housing 14, and the compressor 12 has a compressor wheel 17 disposed in the compressor housing 16. The turbine wheel 15 is driven by the inflowing exhaust gas 18, and the compressor wheel 17 driven by the turbine wheel 15 sucks fresh air 20 from the atmosphere and blows pre-compressed fresh air 21 into the combustion chamber of the internal combustion engine. The exhaust gas 19 flowing out of the turbine wheel 15 advances from the turbine housing 14.

  In internal combustion engines used in passenger cars, a supercharge pressure adjustment is proposed in order to maintain the maximally permissible supercharging pressure so that an advantageous torque regulation can be achieved due to the large speed range. ing. In this case, the desired supercharging pressure is obtained by adjusting the output on the exhaust gas side of the turbine 11. For this purpose, a bypass 22 is provided in the turbine housing 14. Through this bypass 22, a part of the inflowing exhaust gas 18 is guided by the side of the turbine wheel 15 and directly led out together with the outflowing exhaust gas 19. The bypass 22 is controlled by the throttle body 23. The throttle body 23 is formed as a bypass valve 24 in the embodiment of FIG. The bypass valve 24 forming the operating mechanism operated by the actuator 30 is connected to the actuator 30 shown in FIG. 1 via the lever mechanism 25 schematically shown in FIG. The bypass valve 24 is applied to the stopper 26 formed by the seal seat so that power is transmitted by the actuator 30 at the end position where the bypass 22 is completely closed. The seal seat and the bypass valve 24 hermetically seal the bypass 22.

  The actuator 30 has an actuator housing 31 that consists of two parts. The actuator housing 31 includes a pot-shaped base body 311 and a cover 312 that covers the base body 311. In the actuator housing 31, an electric operation motor 32 and a two-stage transmission device 33 are arranged. The operating motor 32 rotates the operating shaft 34 connected to the lever mechanism 25 via the transmission device 33. Normally, a return device (not shown), for example, a return spring acts on the operating shaft 34. The operating shaft 34 is adjusted by the operating motor 32 in the direction of closing the bypass 22 provided in the exhaust gas turbocharger 10 against the force of the return device. The return device realizes a so-called “fail-safe function” and adjusts the bypass valve 24 to a so-called “emergency position” in the turbine housing 14 when the actuator 30 fails. In this emergency position, the bypass 22 is opened. Thereby, the excessive rotation speed of the turbine 11 is avoided. Alternatively, the return device may be omitted and the fail-safe function for the bypass 22 may be realized by the exhaust gas back pressure.

  The two-stage transmission device 33 (see FIGS. 3 and 4) is a non-linear transmission device including a transmission device input stage 35 including a motor pinion 36 and an intermediate gear 37, a driving member 39, and a driven member 40. And an output stage 38. The driving member 39 and the driven member 40 are formed as gears or tooth segments that mesh with each other. This gear or tooth segment rolls on the pitch curve at its outer dentition. The pitch curve radius of this pitch curve changes complementarily over the rotational range of the gear or tooth segment. The driven member 40 is mounted on the operating shaft 34 so as not to rotate relative thereto, while the driving member 39 is connected to the base body 311 in the actuator housing 31 together with the intermediate gear 37 of the transmission device input stage 35. A transmission shaft 41 held between the cover 312 is mounted so as to be relatively rotatable. The drive member 39 and the intermediate gear 37 are coupled to each other via a torque transmission type slip clutch 42. This slip clutch 42 allows a limited relative movement in the transmitted moment between the drive member 39 and the intermediate gear 37 at the end of the operating stroke of the bypass valve 24, and thus for the actuator 30. Provides abutment protection.

  The motor pinion 36 has two immediate teeth rows 43 and 44 arranged side by side in the axial direction. In this case, the parallel straight tooth rows 43 and 44 have the same tooth circle diameter and the same number of teeth, here, for example, 5 teeth. The motor pinion 36 is coupled to the driven shaft 46 of the operating motor 32 by a connecting piece 45 so as not to be relatively rotatable. The teeth of the immediate teeth 43 and 44 provided on both parallel tooth planes are offset from each other by half the tooth pitch, as can be seen in particular in FIG. The doubly toothed motor pinion 36 is manufactured from metal and is manufactured, for example, as a zinc die-cast member, MIM (metal injection molding) member or extruded member. Similarly, the intermediate gear 37 is provided with one immediate tooth row 47 and one immediate tooth row 48 on two parallel tooth planes arranged side by side. Both immediate teeth tooth rows 47 and 48 have the same tooth circle diameter and the same number of teeth, for example, 52 teeth here. The teeth in the immediate teeth row 47 are shifted by half the tooth pitch with respect to the teeth in the immediate teeth row 48. The intermediate gear is preferably manufactured from plastic. Each one immediate tooth row 47; 48 of the intermediate gear 37 meshes with one immediate tooth row 43; 44 of the motor pinion 36.

  As already mentioned, the bypass valve 24 is moved towards the stopper 26 so that power is transmitted after its maximum adjustment stroke of the operating shaft 34 in its closed position. Due to the sealing performance of the bypass 22 in the closed position of the bypass valve 24, a high closing force is required, whereby the bypass valve 24 is applied to the stopper 26 with a high torque. The slip clutch 42 provided between the intermediate gear 37 of the transmission device input stage 35 and the drive member 39 of the transmission device output stage 38 attenuates the torque by a prescribed slip in the slip clutch. For this purpose, the slip clutch 42 is formed so that the flat end surfaces of the intermediate gear 37 and the drive member 39 facing each other are frictionally connected, that is, tightened together in the axial direction so that power is transmitted. ing. When the bypass valve 24 rapidly contacts the stopper 26, the intermediate gear 37 and the drive member 39 are moved in a tangential direction. The force generated in the stopper 26 is defined by the static friction force generated between the intermediate gear 37 and the drive member 39.

  Specifically, the slip clutch 42 includes a mounting flange 49, a boss 50, and a disc spring 51. The boss 50 is formed integrally with the drive member 39 and is formed integrally with the end surface of the drive member 39 on the side facing the intermediate gear 37. The boss 50 protrudes beyond the mounting flange 49 in the axial direction. The intermediate gear 37 is disposed so as to be rotatable relative to the boss 50, and is placed on the upper surface of the mounting flange 49 at the end face facing the drive member 39. The mounting flange 49 itself is mounted on the end surface of the drive member 39 on the side facing the intermediate gear 37 on its lower surface. As can be seen from FIG. 2, the boss 50 has a molded section 501 at its free end. This forming section 501 protrudes beyond the intermediate gear 37. In the illustrated embodiment, the molded section 501 has the shape of a triangular prism with rounded column edges. The disc spring 51 serves to clamp the intermediate gear 37 and the drive member 39 in the axial direction via the mounting flange 49. For this purpose, the disc spring 51 is locked on the molding section 501 of the boss 50 on the one hand and intermediate on the other hand. It is fitted on the boss 50 so as to be pressed against the end surface of the gear 37 on the side opposite to the drive member 39 (see FIGS. 1 and 2). The disc spring 51 is shown in an enlarged plan view in FIG. A circular disc spring 51 manufactured from a spring metal sheet has a central notch 511 and three radial claws 512 that are offset from each other by the same circumferential angle. These radial claws 512 correspond to the column surfaces of the molded section 501, and are fitted into the three column surfaces of the molded section 501 at the free edge when the disc spring 51 is fitted to the boss 50.

  The actuator 30 described above may be used as a regulator or actuator for a throttle valve pipe piece or an exhaust gas recirculation valve. The throttle valve tube piece controls the fresh air flowing into the combustion chamber of the internal combustion engine or the fuel / air mixture supplied to the combustion chamber. The ratio of the amount of exhaust gas added to the new air is controlled by the exhaust gas recirculation valve.

It is a longitudinal cross-sectional view of the actuator provided with the operating motor and the transmission device used for the exhaust gas turbocharger. FIG. 2 is a perspective plan view of the transmission device viewed in the direction of arrow II shown in FIG. 1. FIG. 3 is a perspective enlarged view of a motor pinion provided in the transmission device shown in FIG. 2. FIG. 4 is a bottom view of the transmission device as seen in the direction of arrow IV shown in FIG. 1. FIG. 3 is an enlarged plan view of a disc spring provided in the transmission shown in FIG. 2. It is a partial schematic longitudinal cross-sectional view of an exhaust gas turbocharger.

Explanation of symbols

  10 exhaust gas turbocharger, 11 turbine, 12 compressor, 13 shaft, 14 turbine housing, 15 turbine wheel, 16 compressor housing, 17 compressor wheel, 18 exhaust gas, 19 exhaust gas, 20 new air, 21 new air, 22 bypass, 23 throttle body , 24 Bypass valve, 25 Lever mechanism, 26 Stopper, 30 Actuator, 31 Actuator housing, 32 Actuator motor, 33 Transmission device, 34 Actuation shaft, 35 Transmission device input stage, 36 Motor pinion, 37 Intermediate gear, 38 Transmission device Output stage, 39 Drive member, 40 Driven member, 41 Transmission shaft, 42 Slip clutch, 43 Immediately tooth row, 44 Immediately tooth row, 45 Connecting piece, 46 Driven shaft 47 Immediately teeth tooth row 48 immediately teeth tooth row 49 rests flanges, 50 bosses, 51 disc spring, 311 base body, 312 cover, 501 forming segment,-out 511 notches, 512 radial pawl

Claims (11)

  Actuation mechanism used for the throttle body (23) disposed in a passage for guiding a gaseous medium of an internal combustion engine, which can travel to a stopper, and can be brought into contact with a seal seat so that power can be transmitted. An electric operating motor (32) having a driven shaft (46), an operating shaft (34) coupled to the operating mechanism, a driven shaft (46) of the operating motor (32), In the type in which a transmission device (33) disposed between the operating shaft (34) and the operating shaft (34) is provided, a slip clutch (42) is provided in a force transmission path between the driven shaft (46) and the operating mechanism. An actuator used for an operating mechanism, characterized in that is arranged.   2. Actuator according to claim 1, wherein the slip clutch (42) is integrated in the transmission (33).   The transmission device (33) has a gear pair mounted on the transmission shaft (41) so as to be relatively rotatable, and the gear pair is coupled to each other through a slip clutch (42) so as not to rotate relative to each other. The actuator according to claim 2, comprising two gears.   4. Actuator according to claim 3, characterized in that the slip clutch (42) is realized by an axial frictional connection of the gears via mutually facing end faces.   The slip clutch (42) has a boss (50) protruding in the axial direction integrally formed with one gear and a disc spring (51), and the other gear is rotationally mounted on the boss (50). The disc spring (51) is locked to the boss (50) on the one hand, and supported on the end face of the gear mounted on the boss (50) on the opposite side to the one gear. The actuator according to claim 4.   The boss (50) has a molded section (501) on the end side, and the molded section (501) protrudes beyond the gear that is pivotally mounted on the boss (50), and the disc spring ( 51) has a central notch (511), which projects into the notch (511) for locking the notch (511) in the molding section (501) ( 512. The actuator of claim 5, comprising 512).   A mounting flange (49) is arranged between the end faces of the two gears facing each other, and advantageously, the mounting flange (49) is integrally formed on a gear having a boss (50). The actuator according to claim 5 or 6.   The transmission (33) is formed in a two-stage system, and one gear is an intermediate gear (37) driven by the motor pinion (36) of the transmission input stage (35), and the other gear is A drive member (39) of the transmission output stage (38), the drive member (39) meshing with a driven member (40) rigidly attached to the operating shaft (34). The actuator according to any one of 3 to 7.   9. Actuator according to claim 8, wherein the drive member (39) of the transmission input stage (38) is formed by a gear having a boss (50).   The actuator is used in an exhaust gas turbocharger (10) of an internal combustion engine used in an automobile for adjusting the output of a turbine (11) driven by the exhaust gas of the internal combustion engine. The actuator according to any one of 9 to 9.   The operating shaft (34) is connected to the bypass valve (24) via a lever mechanism (25), and the bypass valve (24) is connected to the turbine wheel (24) in the turbine housing (14) of the turbine (11). Actuator according to claim 10, adapted to control a bypass (22) bypassing 15).

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