This application is based on German Patent Application 10 2005 031 341.8 filed Jul. 5, 2005, upon which priority is claimed.
1. Field of the Invention
The invention is based on a final control element for a control unit, in particular for a throttle body disposed in a conduit, carrying gaseous medium, in an internal combustion engine.
2. Description of the Prior Art
In a known throttle body adjusting unit, having a control shaft supported rotatably in a throttle body brace, the throttle body being secured to the control shaft (German Patent Disclosure DE 195 25 510 A1), a gear wheel, which can be driven via an intermediate wheel by a motor pinion seated on the driven shaft of an electric control motor, is secured to the control shaft outside a gas-carrying conduit whose open cross section is uncovered to a variable extent by the throttle body depending on the rotary position of the control shaft. The error sensor for detecting the rotary angle position of the control shaft is embodied as a potentiometer, with a wiper assembly as the rotor part and with a wiper track assembly as the stator part. The wiper assembly, secured to the face end of the gear wheel, facing away from the gas conduit, includes four wipers, and the wiper track assembly, located on the housing cap of the final control element housing, includes four circular wiper tracks. One wiper presses against each wiper track with spring prestressing.
The final control element according to the invention has the advantage that because the error sensor is embodied as a contactless measurement rotary angle sensor and the power takeoff member of the final control element gear and the rotor part of the rotary angle sensor are combined into a single unit, the production and installation of the final control element are simplified, and the final control element is more-compact and thus saves more space.
In a preferred embodiment of the invention, the rotor part is embodied as a fastening part, which supports the power takeoff wheel and by way of which the connection of the power takeoff wheel with the control shaft in a manner fixed against relative rotation can be made. The rotor part thus simultaneously takes on a supporting function for the power takeoff member of the control unit and, once the rotor part is secured to the control shaft, the drive member is thus fixed as well.
In an advantageous embodiment of the invention, the material and positive engagement between the rotor part and the power takeoff member is produced by means of spraying the plastic power takeoff member onto the rotor part. This makes especially economical manufacture of the dual-function component possible; in the production of the power takeoff member embodied as an injection-molded plastic part, the rotor part is placed in the injection mold.
For securing the rotor part to the control shaft, the rotor part has an inner ring, located coaxially in the power takeoff member and forming a hub of the drive member, and with this inner ring the dual-function component is slipped onto the control shaft and fixed on the control shaft.
In a preferred embodiment of the invention, the rotor part is made from sheet metal, and the plastic of the power takeoff member is injected onto the sheet metal in such a way that one sheet-metal plane is exposed on the face end in the power takeoff member. In the region of the inner ring, the sheet metal is welded to the metal control shaft, for which purpose, between the inner ring and the rotor shaft, a weld bead is produced which extends at least in segments, spaced apart from one another, around the circumference.
The invention will be better understood and further objects and advantages thereof will become more apparent from the ensuing detailed description of a preferred embodiment contained herein below, taken in conjunction with the drawings, in which:
The control shaft 13 is part of a final control element 15, which is received in a final control element housing 16 integrally formed onto the throttle body brace 11. The final control element housing 16 is covered by a housing cap 17. The final control element 15 has an electric control motor 18 with a power takeoff shaft 19, which rotates the control shaft 13 via a final control element gear 20. The final control element gear 20 includes a motor pinion 21, seated on the power takeoff shaft 19 in a manner fixed against relative rotation; a power takeoff member 22, seated on the control shaft 13 in a manner fixed against relative rotation; and an intermediate wheel 24 supported on a shaft 23 in a manner fixed against relative rotation. The shaft 23 is fixed in the final control element housing 16 and in the housing cap 17. The intermediate wheel 24 has two sets of external teeth 241 and 242, extending all the way around and located axially next to one another, with greatly differing numbers of teeth. The external set of teeth 241 meshes with the motor pinion 21, and the external set of teeth 242 is in engagement with the power takeoff member 22, which for this purpose is embodied as a gear wheel segment, with a set of external teeth 221 extending over part of the circumference.
For detecting the pivoted position of the control shaft 13, an error sensor is provided, which is embodied as a contactless measurement rotary angle sensor 25, which detects the rotary angle position inductively, for instance. For this purpose, the rotary angle sensor 25 has a rotor part 26 (
The final control element 15 described may also be used as an actuator for an exhaust gas recirculation valve, with which the proportion of exhaust gas added to the fresh air is controlled. It can also be used in an exhaust gas turbocharger, in which to increase the charge pressure of the aspirated atmospheric air, a compressor is driven by a turbine subjected to exhaust gas. The throttling device actuated by the final control element 15 is located in a bypass, by way of which a portion of the exhaust gas flowing to the turbine is made to bypass the turbine.
The foregoing relates to a preferred exemplary embodiment of the invention, it being understood that other variants and embodiments thereof are possible within the spirit and scope of the invention, the latter being defined by the appended claims.
Number | Date | Country | Kind |
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10 2005 031 341.8 | Jul 2005 | DE | national |