Abstract:
A camshaft adjuster including an electric servo motor ( 21 ) that is mounted in a first housing ( 14 ) and an electronics module ( 37 ), which supplies the servo motor ( 21 ) with electricity is provided. A second housing ( 26 ), which is separate from the first housing ( 14 ), is allocated to the electronics module and is attached by its exterior to the first housing ( 14 ). A wall ( 29 ) of the second housing ( 26 ) separates the servo motor ( 21 ) and the electronics module ( 37 ) to be mounted separately. A power supply and a logic element are integrated into the electronics module, allowing the camshaft adjuster to be operated as an autonomous unit.

Description:
BACKGROUND  
       [0001]     The invention relates to a camshaft adjuster comprising an electric servo motor arranged in a first housing and an electronics module, which supplies the servo motor with electricity, in particular, according to the preamble of claim  1 .  
         [0002]     From DE 103 17 607 A1, a camshaft adjuster is known, which is used for adjusting the relative angular position between a driving chain wheel and a camshaft with the intermediate arrangement of a gear mechanism that can be adjusted by means of an electric servo motor for influencing the timing of an internal combustion engine. The driving chain wheel, camshaft, and gear mechanism are arranged in the area of a clamp, which is screwed onto the internal combustion engine. A housing, which holds the electric servo motor and from which a control shaft of the electric servo motor projects in a direction of the gear mechanism, is supported on the clamp. In the housing, a sensor unit is fixed on the outer periphery of the control shaft, which detects the magnitude of the magnetic poles of the servo motor. Furthermore, within the housing there is a power supply control unit, which is affixed directly to the servo motor. The power supply control unit has a drive circuit, which supplies the servo motor with electrical power, and a control circuit, which is used for controlling the electrical current fed to the electric servo motor. According to another embodiment of the state of the art, the housing has openings, through which an air stream can be drawn for cooling the power supply control unit.  
       SUMMARY  
       [0003]     The invention is based on the objective of creating a camshaft adjuster, which is improved in terms of assembly and/or functionality of the electronic components.  
         [0004]     According to the invention, the objective is met by the features of independent claim  1 . A two-part housing is provided, namely a first housing, which holds or supports the electric servo motor, and a second housing, which is used as a receptacle or support for the electronics module. The electronics module can involve at least one electric component, which is required or is used for operating the servo motor and which is not allocated directly to the servo motor. For example, the electronics module involves a power part, which is used for supplying electrical power to the servo motor, and/or a logic part, which generates, for example, on one hand output signals in terms of operating parameters of the servo motor and/or which is used for regulating or controlling the servo motor. Other possible elements of the electronics module can be an end stage, transistors, an end-stage driver, communications devices, a positioner, a rotational-speed regulator, a current regulator, or a torque regulator. The above components can all be arranged in the second housing or in only one part of this housing, so that other components are arranged either in the first housing, directly allocated to the electric servo motor or else in a decentralized location, for example, in the area of an existing motor control device.  
         [0005]     The electronics module is arranged in the second housing. Here, the second housing can satisfy several functions. First the second housing can form a sealed inner space, which is protected from the entrance of foreign particles from the outside and second, prevents any media in the inner space of the housing from being discharged to the outside. Alternatively or additionally, the second housing can provide a support of the electronics module if the electronics module is attached to this housing. In addition, the second housing forms protection for the electronics module from mechanical or electrical effects from the outside.  
         [0006]     The second housing is attached to the first housing from the outside. In one construction of the camshaft adjuster with the first housing and the second housing, the first housing with the servo motor and the second housing with the electronics module can form separate units, for which separate production, delivery, and/or assembly or disassembly is possible. For example, in the course of maintenance, either the first housing can be opened separately in order to be able to access the electric servo motor or the second housing can be opened in order to perform, for example, repair and maintenance work on the electronics module. Furthermore, through the separate construction of the first and second housing it is possible to select different materials for the material of the housing according to the requirements, whereby the array of possible shapes is increased. For example, in non-load-bearing housing parts, a material of lower strength and lower density can be used. The use of different production methods for the two housings is also conceivable. In addition, for the material selection, different electric requirements, for example, electromagnetic compatibility, isolation, or shielding can be taken into account.  
         [0007]     A wall, which separates the servo motor from the electronics module, is provided between inner spaces defined by the first and second housings. This wall can satisfy different functions: the wall can be used, for example, for supporting the servo motor and/or the electronics module, for providing electrical isolation, or for reducing thermal transport between servo motor and electronics module.  
         [0008]     The servo motor preferably comprises a brushless direct-current motor, which is distinguished by especially good characteristics for operating a camshaft adjuster. For example, it involves a three-phase, in particular bipolar triggered direct-current motor, wherein according to the invention it is allowed that internal rotor motors or disk rotor motors constructed with roller rotors are used. In principle, other types of motors, for example, external rotor motors or brushless alternating current motors or also two or four-phase motors are also conceivable. Furthermore, it is also conceivable that the mentioned variants are also used for unipolar triggering of the motors.  
         [0009]     For a preferred camshaft adjuster according to the invention, an electric connection between the servo motor and the electronics module can be established with the second housing being attached to the first housing via a plug connection. Such a connection can be produced automatically in the course of the second housing approaching the first housing. Here, attachment means of the second housing to the first housing can be used equally for securing the produced plug connection. Such a plug connection can be established both within the housing, wherein, in this case, the housing provides equally a seal of the plug connection from the surroundings or outside of the housing by a plug attached to the housing on the outside. In particular, a plug is integrated directly into the electronics module. In this way, cable extensions projecting out of the electronics module can be avoided. Preferably, such a plug integrated into the electronics module involves plug pins, which are connected directly to the circuit board via lead frames. The number of such plug pins is tailored to the number of desired functions and data to be transmitted (power supply, diagnostics functions, etc.). Furthermore, through the automated connection production for the plug connection via the assembly of the housing, incorrect assembly can be reliably prevented. Furthermore, the number of necessary assembly steps is reduced.  
         [0010]     For an alternative or additional embodiment of the camshaft adjuster, the servo motor and/or the electronics module are connected electrically to at least one electric line running outside of the first housing and/or the second housing. Such an electric line can be connected electrically on one side outside of the housing to the servo motor and the electronics module. Alternatively, the external triggering of the servo motor and/or the electronics module is permitted in this way, for example, by an external controller. Furthermore, operating data of the servo motor and/or the electronics module can be fed back via such an electric line. Preferably, an (automotive) plug is attached to the electronics module. Likewise, it is possible that a cable extension is provided with a plug on a controller of the electronics module. This has the advantage, in particular, that such a plug can be connected directly to a counter plug of a central motor controller and an additional cable tree between a central motor controller and the electric camshaft adjuster is not required.  
         [0011]     Preferably, the electronics module is arranged at least partially radially next to the servo motor. In this way, installation space radially next to the servo motor can be used for the electronics module, wherein the electronics module can be nevertheless positioned adjacent to the servo motor, whereby short electric transmission paths are produced between the servo motor and electronics module.  
         [0012]     According to another aspect of the invention, a second servo motor is provided for the camshaft adjuster. This can be provided as an additional drive in connection with the same camshaft or else as control means for a second camshaft of the same internal combustion engine. The two servo motors can be powered in the same way or differently. Between the two servo motors there is an intermediate space, which can be used according to the invention, so that a compact construction is realized. For example, the distance of the servo motors can be given by the distance of two camshafts. For the given radial size of the servo motors, the intermediate space is produced from these size relationships. Furthermore, according to the invention an uneven end face due to projections from areas of the servo motors can be prevented, because a more or less flat front surface of the camshaft adjuster is produced. The invention makes use of the fact that an arrangement of the electronics module with the individual components, for example, on a circuit board, can be constructed relatively flexibly, so that such an electronics module can also be adapted to curved outer surfaces of the servo motor. Here, the electronics module arranged between the servo motors involves a module for operating one servo motor or two servo motors.  
         [0013]     According to a refinement of the invention, the electronics module has a circuit board with electronic components. These components can involve electronic components of the power unit and/or the logic unit, in particular the end stage, with capacitors, resistors, transistors, metal-oxide semiconductor field-effect transistors (Mosfets), which are used for switching motor phases, end-stage drivers for switching the Mosfets, which can also be integrated into a commutation component, commutation electronics, which are used for determining the phases to be energized, microcontrollers, application-specific integrated circuits (ASICs), etc. A standard circuit board (FR 4 , FR 5 ) or a hybrid solution (for example, a ceramic carrier with copper conductor tracks) can be used. Mixed solutions are also conceivable, for example, a combination of a circuit board with a hybrid component and a foil circuit carrier. Some components and all of the above components can also be mounted directly onto a lead frame. The electronic components can be wired to each other and constructed as surface-mounted devices (SMD) or as non-housed chips (bare dies).  
         [0014]     Preferably the wall is part of the first housing, and the circuit board is mounted directly to the wall. In this way, the circuit board is coupled rigidly to the wall and thus indirectly to the servo motor. Thus, the wall takes on, if necessary, in addition to other functions, a holding function for the circuit board. In this case, the circuit board is then covered or sealed at its attachment to the wall with the second housing. If necessary, other electric components are attached to the second housing.  
         [0015]     According to another construction of the camshaft adjuster according to the invention, several circuit boards are arranged one behind the other parallel to the wall and interconnected. This arrangement presents itself especially when the electronics module is to form a small surface area parallel to the wall. An example application of such a construction is given when the circuit boards are to be arranged in the intermediate space formed between two servo motors.  
         [0016]     Preferably, the electronics module includes sensors for operating states of the motor. These sensors are arranged, in particular, on the side of the electronics module facing the components of the servo motor. These sensors involve, for example, Hall sensors. Alternatively, it is likewise conceivable that Hall sensors or similar sensors are left out, so that sensor-less control is performed.  
         [0017]     Furthermore, it is permitted according to the invention that connections for the three phases of the motor are integrated into the electronics module. These connections are preferably also arranged on the side of the electronics module facing the servo motor. In this way, an especially good and space-saving connection between the electronics module and the servo motor is produced. The connections and especially also connections for any Hall sensors can also be connected to the circuit board.  
         [0018]     Another camshaft adjuster according to the invention is characterized in that between the electronics module and adjacent components there is a heat-conductive paste or a heat-conductive pad. The adjacent components preferably involve components bordering the surroundings, for example, the second housing. In this case, the heat-conductive paste or a heat-conductive pad transfers the heat of the electronics module to the second housing or to a cover, which in this case acts as a heat sink, in that the heat is dissipated from the housing or cover via radiation or convection. In this way, the thermal economy of the electronics module and thus of the camshaft adjuster can be influenced positively.  
         [0019]     Alternatively or additionally, the electronics module can have a cooling device. Such a cooling device involves cooling, in which the electronics module is charged with a cooling medium, such as air or water, via suitable connections. Alternatively or additionally, the cooling device can have ribs, which increase the radiation or convection by increasing the effective external surface area. The mentioned connections involve external connections for an external supply of a cooling medium. Alternatively or additionally, the cooling device can be integrated into an otherwise present coolant circuit, for example, of the cylinder head. It is likewise possible that a fan is used for cooling, which can regulate the heat dissipated through a volume flow. The cooling device of the electronics module can be constructed separate from any other cooling device of the servo motor or can be integrated with the other cooling device.  
         [0020]     For another embodiment of the camshaft adjuster, the first housing with the servo motor forms a structural unit, which can be attached to a housing of the camshaft adjuster. The first housing can thus be connected to the servo motor in a first assembly step with the camshaft adjuster. In a subsequent assembly step, the second housing with the electronics module, which forms another separate structural unit, can be attached to the first housing. A separate disassembly of the second housing is thus also possible. Suitable interfaces for the second housing or the electronics module can be provided on the first housing. According to the invention, a simple exchange of an electronics module is permitted. Furthermore, it is possible that several camshaft adjusters are combined or can be combined with the same or different servo motors and/or the same or different electronics modules, whereby the array of variants is increased while minimizing the production expense.  
         [0021]     The camshaft adjuster, if necessary with the housings and the servo motor as well as the electronics module, can be arranged within a cylinder head housing. Alternatively, the housing of the camshaft adjuster can be attached to a cylinder head housing from the outside.  
         [0022]     An even more compact construction is produced when cylinder head functions are integrated into the structural unit with the first housing and the servo motor. Such cylinder head functions involve, for example, a water-pump connection, a chain tensioner receptacle, a camshaft sensor receptacle, centering the electronics module to the camshaft receptacle bore by means of, for example, a collar or a centering sleeve or the like. A multifunctional use of the wall is produced when this is formed by the second housing and —in addition to the above functions —holds a bearing for a control shaft of the servo motor.  
         [0023]     According to another construction of the invention, the electronics module is encapsulated or extrusion coated with a casing. Such a casing provides a simple but effective seal, which can also protect the electronics module if there is a partial failure of other sealing elements or if there is damage to the housing. In this way, also in extreme situations the electric functionality is guaranteed. Furthermore, a casing can guarantee additional electrical isolation between individual components of the electronics module and/or adjacent electric components. In addition, the casing can provide mechanical protection of the electronics module. Likewise, by means of the casing, a support relative to adjacent components is realized. Such mechanical protective functions are helpful especially as a result of vibrations occurring in the internal combustion engine. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0024]     Additional features of the invention emerge from the following description and the associated drawings, in which embodiments of the invention are shown schematically. Shown are:  
         [0025]      FIG. 1 a  longitudinal cross-sectional view of a servo motor in a first housing and an electronics module in a second housing powering the servo motor;  
         [0026]      FIG. 2 a  view of a first housing for two electric servo motors and one or two electronics modules taken in the direction of an internal combustion engine;  
         [0027]      FIG. 3 a  side view of a first housing with servo motor and with assembled second housing;  
         [0028]      FIG. 4 a  view of an electronics module with an opened cover of the second housing;  
         [0029]      FIG. 5 a  view of the cover for a second housing according to  FIG. 4 ;  
         [0030]      FIG. 6 a  side view of an electric servo motor with a first housing and a second housing according to a second embodiment of the invention;  
         [0031]      FIG. 7 a  view of a first housing for two servo motors;  
         [0032]      FIG. 8 a  side view of an electric servo motor with first housing and second housing according to another embodiment of the invention;  
         [0033]      FIG. 9 a  view of an electronics module for an opened cover for another embodiment, in which the electronics module can be arranged between two servo motors;  
         [0034]      FIG. 10 a  view of the cover for the electronics module according to  FIG. 9 ;  
         [0035]      FIG. 11 a  view of a first housing and second housing with integrated (water) cooling taken in the direction of an internal combustion engine;  
         [0036]      FIG. 12 a  view showing the structural construction of an electric system for a brushless direct-current motor;  
         [0037]      FIG. 13 a  longitudinal cross-sectional view of another embodiment with a servo motor in a first housing and an electronics module in a second housing powering the servo motor, wherein the first and second housing are formed with an integral component. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0038]     The invention finds use for a camshaft adjuster of any type, in which the angular relationship between a driving element (driving gear) and a camshaft is adjusted in line with the rotation of a control shaft  10 . In the figures, as a result of the exchangeability of the basic mechanism of the camshaft adjuster, the drive element, the camshaft, and an intermediate transmission mechanism of the camshaft adjuster are not shown.  
         [0039]     A camshaft adjuster  11  or a cylinder head holding the camshaft adjuster has a housing  12 , which has an opening  13 , here a through hole. A first housing  14  is inserted with an exact fit into the opening  13  from the outside and screwed to the housing  12  via screws  15 . A sealing element  16  is arranged between the housing  12  and the first housing  14 . In the embodiment shown in  FIG. 1 , the sealing element  16  is constructed as a sealing ring, which is held in a radial groove of the opening  13 .  
         [0040]     The first housing  14  is essentially U-shaped in longitudinal section with two parallel side legs  17 ,  18  and a base leg  19  connecting the end regions of the side legs. On their peripheral surface, the side legs  17 ,  18  carry a flange  20  for attaching the first housing  14  to the housing  12  via the screws  15 . In the inner space  65  of the first housing  14  defined by the side legs  17 ,  18  and the base leg  19  there is an electric servo motor  21  with a rotor, which is drivingly connected to the control shaft  10 , as well as a stator, which is supported opposite the first housing  14 . In the shown embodiments, the electric servo motor involves a brushless direct-current motor. The control shaft  10  and servo motor  21  are arranged essentially coaxial to a longitudinal axis X-X.  
         [0041]     The base leg  19  provides a central bearing bore  22 , through which the control shaft  10  projects from the inner space  65  of the first housing  14  in a direction of the gear mechanism of the camshaft adjuster  11 . In the region of the bearing bore  22 , the control shaft  10  is supported by an anti-friction bearing  23 , here a ball bearing, opposite the first housing  14 . A sealing element  24 , which seals the inner space  65  of the first housing  14  from the outside and/or from the inside, is supported in front of the anti-friction bearing  23  in a direction of the internal combustion engine. In the embodiment shown in  FIG. 1 , the sealing element  24  involves a radial shaft sealing ring, which acts between the inner surface of the bearing bore  22  and the outer surface of the control shaft  10 .  
         [0042]     The first housing  14  is thus approximately “pot-shaped” with a circular opening  25 , which lies opposite the base leg  19 . The opening  25  is at least partially closed by a second housing  26 .  
         [0043]     The second housing  26  is in the shown longitudinal section essentially U-shaped with two parallel side legs  27 ,  28  and a wall in the form of a base leg  29 . The cross section of the base leg  29  corresponds to the first housing  14  and closes at least partially the opening  25 . In the contact area of the base leg  29  with the end regions of the side legs  17 ,  18  of the first housing  14  there is a sealing element  30  between the first housing  14  and the second housing  26 . In the embodiment shown in  FIG. 1 , the sealing element  30  involves a sealing ring, which is held in a circumferential groove of the first housing. The side legs  17 ,  18  and also  27 ,  28  have, in the contact area, radial projections or a flange  31 , in the area of which the first housing  14  and the second housing  26  are screwed to each other. A centering projection  32  of the second housing  26 , which contacts the side legs  17 ,  18  for the exact alignment of the housings  14 ,  26  relative to each other under the formation of a fit, extends in the direction of the interior of the first housing  14 .  
         [0044]     The base leg  29  carries in the center a circular ring-shaped bushing  33 , which extends from the base leg  29  in the direction of the inner space  65  of the first housing  14 . The bushing  33  is supported radially on the inside an anti-friction bearing  34 , here a ball bearing, which supports the control shaft  10  on the side of the electric servo motor  21  facing away from the anti-friction bearing  23 . Thus the control shaft  10  is supported with the rotor connected to it in the anti-friction bearing  23  opposite the first housing  14  and also in the anti-friction bearing  34  opposite the second housing  26 .  
         [0045]     An inner space  35  defined by the side legs  27 ,  28  and the base leg  29  is closed under the use of a cover  36 . An electronics module  37  is fit into the inner space  35 . Between the electronics module  37  and cover  36  there is, furthermore in the inner space  35 , a heat-conductive paste or a heat-conductive pad  38 , which contacts the cover  36  and also the electronics module  37  over a large area, especially under the formation of a contact pressure force. A sealing element  39  is arranged between the cover  36  and the end faces of the side legs  27 ,  28 . According to  FIG. 1 , the sealing element  39  comprises a sealing ring, which is inserted in an axial groove of the second housing  26 .  
         [0046]     For the embodiment shown in  FIG. 1 , the base leg  29  of the second housing has openings  40  distributed over the circumference. Plugs  41  from the electronics module  37  project through the openings  40 . The electric servo motor  21  provides correspondingly constructed plug receptacles  42  in the corresponding areas. With the insertion of the second housing  26  with the electronics module  37  and plugs  41 , an electric connection between the plug  41  and plug receptacle  42  is automatically produced, wherein the exact alignment of the plug  41  and plug receptacle  42  can likewise be guaranteed via the centering projection  42  and the corresponding inner dimensions of the first housing  14 .  
         [0047]      FIG. 2  shows the cover  36  of the second housing  26  and a first housing  14  for a view in the direction of the X-X axis in the direction of an internal combustion engine. The first housing  14  can be screwed to a housing of the camshaft adjuster  11  or else to a cylinder head via several bores  66 .  
         [0048]      FIG. 3  shows a non-sectioned side view of the camshaft adjuster  11  according to the invention.  
         [0049]     According to  FIG. 2 , two electric servo motors are arranged one next to the other in the first and second housings  14 ,  26 , so that the cover  36  and the housing  14 ,  26  are elongated, in particular, approximately rectangular.  
         [0050]      FIG. 4  shows the electronics module  37  in a representation with more detail relative to  FIG. 1  for a view in the direction of the X-X axis and opened cover  36  (cf.  FIG. 5 ). The electronics module  37  has a circuit board  43 , which is in electrical connection with plugs  45  in the region of receptacles  44  when the circuit board  43  is inserted into the second housing  26 . These plugs are connected electrically, in turn, to a plug  46  arranged outside the second housing  26 . The electronics module  37  with additional external electrical devices can be connected via the plug  46 .  
         [0051]     The circuit board  43  further has plugs or connections  47  for the attachment of connections of the motor or Hall sensors. The circuit board  43  carries a plurality of electric components  48 . The second housing  26  can provide centering bores  49 , which permit alternatively or additionally the cover  36  to be clipped on for centering.  
         [0052]     The electric components  48  involve, in particular, a power unit and/or a logic unit of an end stage, capacitors, resistors, transistors, microcontrollers, ASICs, etc. The plugs  45 ,  46  and connections  47  are connected to the circuit board  43  via lead frames. The number of plugs  45 ,  46  and connections  47  is tailored to the number of desired functions and the data to be transmitted (power supply, diagnostics functions, etc.). In addition, it is advantageous when sensors, such as Hall sensors of the electric servo motor  21 , are integrated into the electronics module  37  on the side facing the motor components. Furthermore, connections  50  for the three phases of the electric servo motor  21  can be integrated.  
         [0053]      FIG. 7  shows the first housing  14  for a view in the direction of the X-X axis without the second housing  26  and without the electric servo motor  21 . As is visible from  FIG. 7 , an intermediate space  61 , which is unused, is produced between the two recesses for the two electric servo motors  21 . For the deviating construction of the electronics module  37  and the second housing  26  shown in  FIGS. 8 and 9 , the intermediate space  51  can be used, in that the electronics module  37  and the second housing  26  are inserted into this space. In this case, the second housing  26  has an approximately rectangular cover  52 , which closes the inner space  65  of the first housing  14  for an electric servo motor  21  in the outer areas  53 ,  54 . A chamber  55  of the second housing  26  projects between the areas  53 ,  54  opposite these, wherein this chamber enters into the intermediate space  51  and preferably comes into contact with or is slightly spaced apart from the first housing  14  in the area of an end face. The chamber  55  is included in the electronics module  37 . The circuit board  43  is constructed in this case not in one piece but instead in several pieces, wherein individual parts of the circuit board  43  are arranged one behind the other parallel to the plane of the drawing according to  FIG. 9 . The chamber  55  can be closed by means of the cover  56  shown in  FIG. 10 .  
         [0054]     According to  FIG. 11 , the first housing  14  and/or the second housing  26  can provide connections  57 ,  58 , by means of which the inner spaces  35 ,  65  of the first housing  14  and the second housing  16  as well as the electric servo motor  21  and the electronics module  37  can be charged with a coolant, in particular air or water.  
         [0055]      FIG. 12  shows a basic construction of an electric servo motor  12  with electronics module  37 . The electronic servo motor  21 , optionally a motor sensor, such as Hall sensors  59 , an end stage (transistors)  60 , an end stage driver  61 , a commutation device  62 , optionally a rotational-speed regulator, current or torque regulator  63 , and a positioner  64  are connected electrically or in terms of signals as sketched. All or parts of the above components can be integrated into the electronics module  37 .  
         [0056]     A controller is preferably integrated into the electronics module  37 , so that triggering or regulation is not performed in a decentralized arrangement, for example, by means of a vehicle controller, but instead the camshaft adjuster  11  represents an autonomous unit (under some circumstances up to the voltage power supply). In this way, wiring expense (for example, a cable with a plug) from the vehicle controller to a controller of the brushless direct-current motor and a cable with plug from the controller of the brushless direct-current motor to the brushless direct-current motor can be spared. As a result of the unneeded wiring, electrical losses and EMC problems can be avoided or increased expense for shielding possible wiring can be eliminated. In this way costs can be minimized.  
         [0057]     The first housing  14  and/or the second housing  26  can be comprised of steel, aluminum, plastic, or other possible materials. The circuit board  43  can be attached to the first housing  14 , the base leg  29  of the second housing  26 , or to a side leg  27 ,  28  of the second housing, for example, it can be screwed or connected to carry a material flow with these parts. Alternatively, a circuit support receptacle can be arranged between the above components and the circuit board  43 .  
         [0058]     Preferably, both a power unit and also a logic unit can be integrated into the electronics module  37 , wherein solutions are also conceivable, in which only the power unit is attached to the electric servo motor  21 . The logic unit is then, in turn, integrated into a separate controller or ideally into the existing controller. If only one servo motor  21  is to be used, then the second housing  26  with the electronics module  37  can be arranged axially on the servo motor  21 , but also laterally offset relative to this servo motor, or else it is located in the first housing  14 . The ideal arrangement depends on the corresponding application and must be selected individually.  
         [0059]     Advantageously, various cylinder head functions are integrated into the first housing, for example, a water-pump connection, a chain tensioner receptacle, a camshaft sensor receptacle, a centering module for the camshaft receptacle bore (e.g., collar, centering sleeve, etc.).  
         [0060]     For the use of two or more servo motors, it is conceivable to arrange the electronics in an electronics module  37  as shown, with which all of the electric servo motors  21  can be activated. Alternatively, it is also possible that each electric servo motor  21  is equipped with at least one separate electronic unit and a separate one-part or multiple-part electronics module  37 .  
         [0061]     Advantageously, only certain blocks are integrated into the first housing  14  or the second housing  26 , for example, depending on temperature stability or vibration resistance of the component, while other blocks, which are less stable, are integrated into a separate controller or in the vehicle controller. Here, advantageously the end stage, in which, for example, transistors are bonded directly to a lead frame instead of onto a circuit board, is integrated into the first housing  14  or the second housing  26  and the commutation and regulation electronics are arranged in a separate, external controller or in the vehicle controller. Alternatively, it is also conceivable that the end stage, commutation, and regulation devices are arranged completely in the first housing  14  or second housing  26  or completely in a vehicle controller or completely in a separate controller.  
         [0062]     An especially good heat dissipation is provided when the cover  36  is made from a good heat-conductive material, for example, aluminum or steel. To prevent the electronics module  37  from being heated by the hot cylinder head, it is advantageous that the electronics, especially the electronics module  37 , are shielded from the cylinder head by an insulator. Alternatively, this can be realized in that the electronics module  37  is produced at least partially from plastic or that the second housing  26  is produced from plastic. In this way, heat transfer from the cylinder head via the first housing  14  and/or the second housing  26  to the electronics module  37  is prevented. Alternatively, an insulating layer, for example, an insulating intermediate support made from plastic, can also be arranged between the electronics module  37 , first housing  14 , and second housing  26 . In this case, the electronics module or one of the housings  14 ,  26  can be produced from metal. Finally, it is also conceivable that an insulating layer is located between the first housing  14 , second housing  26 , and cylinder head.  
         [0063]     All of the components can be cooled by means of coolant circuits or other cooling mechanisms, for example, by means of cooling ribs on the electronics module  37 , module  36 , first housing  14 , and/or second housing  26 . A fan or a coolant flow of an existing coolant circuit of the vehicle can be used.  
         [0064]     In addition, it is advantageous when the electronic components are protected from penetrating fluids, such as water, oil, acids, or the like. For this purpose the mentioned sealing elements  30 ,  39 ,  16  are used, which can involve any sealing element, such as radial shaft sealing rings,  0 -rings, or molded seals. Additional protection against such fluids is given by encapsulation of the components or the electronics module  37 , because in this way, even if a seal fails, the components or the electronics module  37  is still protected from penetrating fluids. In addition, it is conceivable to seal the areas, in which the contacts of the electronics module  37  are connected to the contacts of the electric servo motor  21  (feedthroughs of the contacts also to the second housing  26 ), e.g., through encapsulation of the contacts or through a single contact seal.  
         [0065]      FIG. 13  shows an alternative construction of the invention, for which the two housings  14   a  and  26   a  are not formed with separate components, but instead with a common component. Here, the second housing  26   a  is arranged radially next to the first component  14   a  and the servo motor  21 , for example, underneath these parts. The housings  14   a  and  26   a  have a common limiting wall  67 , which is produced in the transition area from the first housing  14   a  to the second housing  26   a  and which is formed in the longitudinal section shown in  FIG. 13  in the area of the side leg  18 . The common wall  67  has a radially oriented opening  68 , which can also be constructed as a radial, continuous recess formed in the wall  67  in the axial direction. Electric lines or plugs  41  and plug receptacles  42  project through the opening  68 , by means of which electric communications and power supply is realized between the servo motor  21  and the electronics module  37 .  
       LIST OF REFERENCE SYMBOLS  
       [0000]    
       
           10  Control shaft  
           11  Camshaft adjuster  
           12  Housing  
           13  Opening  
           14  First housing  
           15  Screws  
           16  Sealing element  
           17  Side leg  
           18  Side leg  
           19  Base leg  
           20  Flange  
           21  Electric servo motor  
           22  Bearing bore  
           23  Anti-friction bearing  
           24  Sealing element  
           25  Opening  
           26  Second housing  
           27  Side leg  
           28  Side leg  
           29  Base leg  
           30  Sealing element  
           31  Flange  
           32  Centering projection  
           33  Bushing  
           34  Anti-friction bearing  
           35  Inner space of second housing  
           36  Cover  
           37  Electronics module  
           38  Heat-conductive pad  
           39  Sealing element  
           40  Openings  
           41  Plug  
           42  Plug receptacle  
           43  Circuit board  
           44  Receptacles  
           45  Plug  
           46  Plug  
           47  Connections  
           48  Components  
           49  Centering bore  
           50  Connections  
           51  Intermediate space  
           52  Cover  
           53  Area  
           54  Area  
           55  Chamber  
           56  Cover  
           57  Connection  
           58  Connection  
           59  Hall sensors  
           60  End stage  
           61  End stage driver  
           62  Commutation  
           63  Regulator  
           64  Positioner  
           65  Inner space of first housing  
           66  Bore  
           67  Common wall  
           68  Opening