Abstract:
In a throttle valve actuator unit having a throttle valve neck that contains a pivotable throttle valve and having a drive chamber for receiving an electric drive mechanism for the throttle valve and for receiving an electric connection plug for a plug connection to a control unit, in order to reduce the production costs while maintaining the many customer-specific characteristics, the drive chamber is enclosed by a housing module, and the throttle valve neck is attached as a separate part to the housing module and secured thereto.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application is a 35 USC 371 application of PCT/DE 01/03696 filed on Sep. 26, 2001. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The invention is directed to an improved throttle valve actuator unit for an internal combustion engine. 
   2. Description of the Prior Art 
   In a known throttle valve actuator unit (German Patent Disclosure DE 195 25 510 A1), also known as an electronic throttle control or ETC, a drive chamber is formed in the throttle valve neck, through which neck a gas conduit carrying air or a fuel-air mixture extends; the drive chamber is closed with a plastic cap and contains a drive motor, a reducing gear connecting the motor to the throttle valve shaft, and a connection plug for connecting the throttle valve actuator unit to an electric control unit. The connection plug is embodied on the plasticcap. The throttle valve actuator unit has customer-specific characteristics with regard to the diameter of the throttle valve neck, the dimensions of the securing flange on the throttle valve neck, and the embodiment of the connection plug, and so special production tools must be kept on hand for every customer; some of these tools are quite expensive, and therefore considerably increase the production costs for the throttle valve actuator unit. 
   A transition has therefore already been made to a modular system, with which graduated diameter variants for the throttle valve neck and the flange dimensions can be offered to customers with one small and one large model series, each of which is offered with two different connection plugs; this accordingly meets the majority of customer-specific characteristics. However, for each type of one model series, its own tool is required. Each plug variant must also be provided with its own tool for the plastic cap, in both the large and the small model series. 
   SUMMARY OF THE INVENTION 
   The throttle valve actuator unit of the invention has the advantage that because of its modular design, only a single housing module is needed for each model series of the modular system, and then the relatively simple throttle valve neck with a diameter and flange embodiment adapted to customer specifications can be attached to the housing module by the manufacturer. As a result, the throttle valve neck itself can be designed such that a plurality of stub diameters can be accommodated using only a single tool. 
   In a preferred embodiment of the invention, the connection plug is likewise attached as a separate part to the housing module and secured to it. As a result, the connection plug can be prefabricated at the factory in various versions that meet customer specifications and mounted on the housing module in the same position. The plug pins themselves can be connected to the other required contact points by way of a printed circuit board, which is prepared to receive various plug variants. 
   In an advantageous embodiment of the invention, a connecting scoop with an individually adapted hose connection geometry is inserted as a separate pipe segment into the throttle valve neck. The pipe segment made as a separate part of plastic or metal can easily be designed in terms of its hose connection geometry to meet customer demands and then inserted into the throttle valve neck, for instance being press-fitted or glued into place. 
   In a preferred embodiment of the invention, the throttle valve neck is produced as an extruded profile. This has the advantage of substantially lower production costs, compared to the die-casting process employed until now, as well as of substantially lower tool costs. In particular, the extruded profile embodiment also offers the possibility of accommodating multiple throttle valve diameters with a single tool. The extruded profile is manufactured as an endless profile with the appropriate inside diameter and flange dimensions of the throttle valve neck and is then cut to the required length of throttle valve neck. The blank cut to the appropriate length is then machined into the desired final form by removal of material. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention is described in further detail below, with reference to the drawings, in which: 
       FIG. 1 , a perspective view of a throttle valve actuator unit; 
       FIG. 2 , an exploded perspective view of the throttle valve actuator unit in  FIG. 1 , with a throttle valve neck removed from a housing module; 
       FIG. 3 , a perspective view of a blank, cut to the appropriate length from an extruded profile, for a modified throttle valve neck; and 
       FIG. 4 , a perspective view of the throttle valve neck after machining of the blank of FIG.  3 . 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   In the throttle valve actuator unit for an internal combustion engine shown in its assembled form in FIG.  1  and in  FIG. 2  in individual parts, in each case in perspective, a throttle valve neck  11  is placed on a housing module  12  and solidly joined to it. A throttle valve shaft  14  that carries a throttle valve  13  is rotatably supported in the throttle valve neck  11 . The housing module  12 , preferably made from plastic, which encloses a drive chamber for receiving an electric drive mechanism of the throttle valve shaft, has a shell-shaped base body  15  and a cap  16  that closes the base body  15 , as well as having a hollow-cylindrical receiving compartment  17 , which is formed onto and integral with the base body  15  and projects at a right angle from the base body  15 . The electric motor of the drive mechanism is received in the receiving compartment  17 ; one end of the power takeoff shaft of the motor is supported rotatably in a bearing plate  18 , which closes off the end, remote from the base body  15 , of the receiving compartment  17 . A through opening  19  is formed in the base body  15  at a distance from the receiving compartment  17 , and its normal or opening axis is oriented parallel to the longitudinal axis of the receiving compartment  17 . When the throttle valve neck  11 , provided with the throttle valve  13  and throttle valve shaft  14 , is attached to the housing module  12 , one end of the throttle valve shaft  14  passes through the through opening  19  into an inner chamber enclosed by the base body  15 . Inside this inner chamber, the throttle valve shaft  14  is coupled mechanically, via a reducing gear, to the motor power takeoff shaft of the electric motor, which shaft also protrudes into the inner chamber; this is described in detail and shown in DE 195 25 510 A1. As in the aforementioned reference, there is a sensor, not shown here, in the inner chamber for reporting the pivoted position of the throttle valve  13 , but the sensor is disposed on the base body  15  (rather than on the cap  16 ). Both the terminals of the electric motor and the terminals of the sensor are extended to a plug  20 , by way of which a plug connection with a control unit can be made. The plug  20 , like the throttle valve neck  11 , is embodied such that it can be attached to the housing module  12 , specifically to the base body  15 , and can be fixed thereon. For positionally correct attachment of the throttle valve neck  11  and the plug  20  to the housing module  12 , seats are formed on the base body  15 , on the one hand, and on the throttle valve neck  11  and the plug  20  on the other; on being joined, these seats mesh with one another and assure the precise-tolerance position of the throttle valve neck  11  and plug  20  on the housing module  12 . Pairs of seats between the base body  15  and the throttle valve neck  11  are marked in  FIG. 2  by reference numerals  21 ,  21 ′ and  22 ,  22 ′. One pair of seats between the base body  15  and the plug  20  is marked  23 ,  23 ′. 
   For the sake of offering a wide variety of versions of the throttle valve actuator unit that are adapted to client demands yet have low production costs, the throttle valve neck  11  and the plug  20  are—as described—separate parts, readied for connection to the housing module  12  but manufactured detached from the housing module  12 , and are accordingly easy to adapt to customer-specific requirements. Such requirements include different diameters of the throttle valve neck  11  and different dimensions of the securing flange  111  embodied on the throttle valve  11 . In the plug  20 , the number and arrangement of the pins also vary, depending on customer demands. These separately produced parts are then attached to the housing module  12  positionally accurately by means of the seats  21 - 23  in the desired embodiments and fixed thereon, for instance by clamping pins. 
   For the sake of further cost advantages in production of the throttle valve actuator unit, the throttle valve neck  11  is produced as an extruded profile. The extruded profile is made as an endless profile, and from the extended profile blanks with a length required for the throttle valve neck  11  are then cut. One such blank  25 , cut to the proper length from an extruded profile, is shown in FIG.  3 . This blank  25 , because of the extruded profile, already has essentially the desired inside diameter of the throttle valve neck  11  and the dimensions of the securing flange  111 . This blank  25  is then put into the desired final form of the throttle valve neck  11 , as shown in  FIG. 4 , by machining that removes material. The throttle valve neck  11  shown in  FIGS. 1 and 2  is manufactured in the same way. 
   Once the throttle valve neck  11  with the throttle valve  13  and throttle valve shaft  14  is completed, the throttle valve neck  11  is further provided with a connecting scoop  24  onto which a connection hose can be slipped. On its free end protruding from the throttle valve neck  11 , the connecting scoop  24  has a hose connection geometry  241  that must in turn be designed differently for various customers. To meet customer demands while lowering production costs, the connecting scoop  24  is made as a separate pipe segment of plastic or metal and then inserted into the throttle valve neck  11 . Once again, the separate production of the connecting scoop  24  makes it possible to adapt the hose connection geometry economically to customer demands. Securing the pipe segment in the throttle valve neck  11  is done for instance by press-fitting or gluing. The position of the pipe segment in the throttle valve neck  11  can be specified by an annular stop shoulder  26  ( FIGS. 2 and 4 ) formed onto the inner wall of the stub. 
   The invention is not limited to the exemplary embodiment described above. For instance, the throttle valve neck  11  and connecting scoop  24  may also be integral, for instance by producing the connecting scoop  24 , after the blank  25  has been suitably cut to length from the extruded profile, by means of material-removing machining. Alternatively, if the advantages of the extruded profile production are dispensed with, a cast body of plastic or metal that includes both a throttle valve neck  11  and a connecting scoop  24  can be produced by casting technology; it may also require postmachining afterward. 
   The foregoing relates to preferred exemplary embodiments 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.