Patent Publication Number: US-2023151861-A1

Title: Actuator assembly for a vehicle brake and method for manufacturing an actuator assembly for a vehicle brake

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to German Priority Application No. 102021129955.1, filed Nov. 17, 2021, the disclosure of which is incorporated herein by reference in its entirety. 
     TECHNICAL FIELD 
     The disclosure relates to an actuator assembly for a vehicle brake. The disclosure is furthermore based on a method for manufacturing an actuator assembly for a vehicle brake. 
     BACKGROUND 
     An actuator assembly in this case serves to move a brake pad of an associated vehicle brake into a braking position in which it is applied to a brake rotor, for example a brake disc, with a certain contact force. hi some cases, actuator assemblies are also used to actively lift the brake pad off the brake rotor and thus transfer it to a rest position. 
     Given that vehicle brakes and associated actuator assemblies are produced in high quantities, it is important to configure actuator assemblies in such a way that they can be manufactured in a simple and cost-effective manner. Simple and cost-effective installation is particularly important in this case. 
     SUMMARY 
     This is where the disclosure comes in to play. What is needed is to create an actuator assembly which can be manufactured in a particularly simple and cost-effective manner. 
     Accordingly, an actuator assembly of the type mentioned at the outset is provided, which has a control assembly, which can be installed as a separate sub-unit and which comprises a partition panel and a circuit board fastened to said partition panel. The actuator assembly furthermore has a drive assembly, which can be installed as a separate sub-unit and which comprises a carrier assembly, on which an electric motor, a spindle drive and a gear unit are mounted, which gear unit drivingly couples the electric motor and the spindle drive. In one exemplary arrangement, a driven shaft of the electric motor is aligned substantially perpendicularly to the partition panel and to the circuit board. The control assembly and the drive assembly are arranged in a common housing. In this case, the housing is designed as a sub-unit of the actuator assembly, which sub-unit is separate from the control assembly and the drive assembly. The control assembly and the drive assembly are also mutually separate sub-units. The control assembly, the actuator assembly and the housing can therefore firstly be produced separately from one another, which can take place in parallel. The manufacture of the actuator assembly then only requires the control assembly and the drive assembly to be inserted into the housing. This is comparatively simple and can take place within a short period of time. All in all, the actuator assembly can therefore be manufactured in a very simple, rapid and cost-effective manner. Given that the control assembly is designed to be part of the actuator assembly, the actuator assembly moreover has comparatively few external interfaces. This can therefore be installed in a vehicle with little effort. 
     In one exemplary arrangement, the electric motor which is present in the actuator assembly is designed as a brushless DC motor. It can be a three-phase motor, Such an electric motor can be operated in an efficient manner. Moreover, it can provide a comparatively high torque relative to its volume. In other words, such an electric motor is compact. 
     Moreover, respective centre axes of the spindle drive and the electric motor are advantageously arranged in parallel. A compact construction of the drive assembly and therefore the actuator assembly as a whole is thus achieved. 
     The circuit board of the control assembly is provided with a printed circuit, for example. Alternatively or additionally, electrical and/or electronic components are arranged and electrically contacted on the circuit board. 
     In one exemplary arrangement, the partition panel of the control assembly is manufactured from plastic material. If the partition panel is provided with edges, it can also be referred to as a partition compartment. The partition compartment may also be manufactured from plastic material. 
     In one exemplary arrangement, the partition panel is positioned on a side of the control assembly which faces the drive assembly. In the installed state, the partition panel is then located between the drive assembly and the circuit board. It therefore represents a dividing wall between the components of the drive assembly and the components of the control assembly. 
     Positioning and/or fastening devices for the drive assembly can moreover be provided on the housing. Appropriate devices for positioning and/or fastening the control assembly can also be provided on the housing. Alternatively or additionally, it is possible that the drive assembly comprises devices for positioning and/or fastening the control assembly. The reverse situation is also conceivable, i.e, the control assembly can comprise devices for positioning and/or fastening the drive assembly. A combination of these alternatives is also possible. 
     The housing can be manufactured from plastic material, at least in part. Such housings can be manufactured in a simple and cost-effective manner, for example using an injection moulding technique. 
     In one exemplary arrangement, the housing is manufactured entirely from plastic material. 
     According to one exemplary arrangement, the housing comprises a substantially shell-shaped housing base part and a housing cover which closes the housing base part. Such a construction is structurally simple. Moreover, a housing base part and a housing cover can be manufactured in a simple and cost-effective manner. In this case, the housing cover can also be shell-shaped. Alternatively, the housing cover can be plate-shaped. 
     In one exemplary arrangement, the housing base part and the housing cover are tightly welded to one another in the installed state. The control assembly and the drive assembly are therefore reliably protected against undesirable environmental influences. 
     According to one exemplary alternative, a cooling body made of metal is provided on the housing cover, which cooling body contacts at least one electrical or electronic component of the circuit board in a thermally conductive manner. Heat which is generated during operation of the circuit board can thus be reliably dissipated to the environment. 
     According to another exemplary alternative, the housing cover is manufactured from metal and serves overall as a cooling body. The housing cover is then coupled to at least one electrical or electronic component of the circuit board in a thermally conductive manner so that heat which is generated during operation of the circuit board can be reliably dissipated to the environment via the housing cover. 
     An arrangement for positioning and fastening the circuit board can be provided on the partition panel. The circuit board can thus be positioned and fastened on the partition panel in a simple and reliable manner. In this case, the positioning comprises both a translatory and a rotational positioning. Centring represents a special type of positioning. 
     In one exemplary arrangement, retaining ribs for lubricating medium are arranged on a side of the partition panel which faces the drive assembly. In the installed state of the drive assembly and the control assembly, the retaining ribs are adjacent to components of the drive assembly. To enable efficient operation of these components, they can be provided with a lubricating medium, for example lubricating grease. The retaining ribs now have the effect of also keeping the lubricating medium in the region of the associated components during operation of the actuator assembly. This applies in light of the centrifugal forces which occur during operation of the drive assembly. All in all, good reliability and operational safety of the actuator assembly can thus be ensured. 
     A plug-connector half can also be integrally provided on the housing, wherein the plug-connector half is electrically connected to the circuit board via at least a first electric line. In this case, describing the line as a “first” line merely serves for simple explanation. A number of lines is not implied. The plug-connector half can be designed to supply the actuator assembly with electric energy. Alternatively or additionally, it is conceivable for the actuator assembly to be connected to a bus system, e.g, a CAN bus system, via the plug-connector half. It is also possible to couple a wheel speed sensor to the actuator assembly via the plug-connector half, which wheel speed sensor is associated with a wheel to be braked. The actuator assembly is therefore reliably supplied with the required energy and the signals which are required for operation. 
     In one exemplary arrangement, the components of the plug-connector half are integrated at least partially in the housing. In this case, the components of the plug-connector half can be pressed into the housing or overmoulded with portions of the housing. Both variants can be produced in a technically simple manner. 
     In this case, it is possible for the first electric line to be integrated in the housing, at least in part, wherein a portion of the first electric line which is on the circuit-board side extends substantially parallel to the driven shaft of the electric motor. The first electric line is injection moulded into the housing, for example. The installation of the actuator assembly is thus very simple. 
     In one exemplary arrangement, the first electric line is dimensionally stable. This applies especially to the portion thereof which is on the circuit-board side. Contacting of the circuit board is therefore possible via a press connection or an insulation displacement connection. The electrical contacting therefore involves little effort. 
     The electric motor and the circuit board can be electrically connected via a second electric line, wherein the second electric line extends substantially parallel to the driven shaft of the electric motor. This results in a comparatively short second electric line. A structurally simple construction of the actuator assembly is thus achieved. 
     In one exemplary arrangement the second electric line is also dimensionally stable. The effects and advantages achieved are the same as those which have already been explained with respect to the first electric line. 
     Moreover, the partition panel and the circuit board can be connected via a potting material, at least in part. Electric lines provided on the circuit board as well as electrical and/or electronic components can thus be protected against environmental influences. This applies especially to vibrations and moisture. In one exemplary arrangement, the potting material is introduced into the subassembly comprising the circuit board and the partition panel before said subassembly is installed in the housing. 
     Moreover, passages, which are delimited by edges, can be provided on the partition panel, wherein the edges serve to keep the passages free of potting material. In this case, passages for the first electric line and/or the second electric line are provided with such edges, for example. 
     The control assembly can comprise a speed regulating unit for regulating a speed of the electric motor and/or a current measuring unit for measuring a current received by the electric motor and/or a current supply unit for supplying the electric motor with electric energy and/or a temperature measuring unit for measuring a temperature within the actuator assembly and/or a force measuring unit for measuring a brake actuating force provided by the actuator assembly and/or a rotational position detection unit for detecting a rotational position of the electric motor and/or an actuating unit for a locking assembly for blocking the driven shaft of the electric motor against rotation. In this connection, the power supply unit can also be referred to as power electronics. All in all, numerous electrical or electronic type functionalities are provided directly in the actuator assembly. In this connection, it is also possible to refer to these functions as being decentralised or locally available. Installation of the actuator assembly is thus simplified, since the number of external interfaces is comparatively small. 
     In one alternative arrangement, a magnet is arranged on an end of the driven shaft of the electric motor which faces the control assembly. A sensor which is associated with the magnet is positioned on the circuit board such that it is substantially opposite the end of the driven shaft. Accordingly, the magnet can also be referred to as a sensor magnet. In one exemplary arrangement, the magnet is a permanent magnet. The sensor is for example a Hall sensor or an inductive sensor. In both alternatives, a rotational position of the driven shaft of the electric motor can be determined by the magnet and the sensor. If associated sensor signals are evaluated over time, motor revolutions can also be detected. Both alternatives are simple and serve for reliable operation of the actuator assembly. 
     In this case, it is possible to deduce a spindle nut travel and a spindle nut position of a spindle nut of the spindle drive on the basis of the revolutions of the driven shaft of the electric motor, since there is a constant relationship between the revolutions of the electric motor and the spindle nut travel. With knowledge of the system rigidity of the actuator assembly, and depending on the associated brake pad thickness and the temperature, the value of an application force for the vehicle brake which is currently being generated by the actuator assembly can furthermore be determined using the spindle nut travel or the spindle nut position. 
     By measuring a current consumption of the electric motor, it is also possible to deduce the currently generated motor torque. From this, it is possible to derive the torque introduced into the spindle drive and, in turn, the application force, since the transmission ratios are constant and only the current level of efficiency needs to be evaluated. 
     In a further alternative arrangement, the application force can be measured by an integrated force sensor. 
     In a situation in which there are two more measurement values for the application force, these can be compared for the purpose of fault detection. In this case, for example, a fault situation can be deduced if the measurement values deviate from one another by more than a specified amount or more than a specified percentage. 
     A method for manufacturing an actuator assembly for a vehicle brake, comprising the following steps is also disclosed: 
     a) providing a substantially shell-shaped housing base part, 
     b) inserting a drive assembly into the housing base part, which drive assembly comprises a carrier assembly on which an electric motor, a spindle drive and a gear unit are mounted, which gear unit drivingly couples the electric motor and the spindle drive. 
     c) inserting a control assembly into the housing base part, which control assembly comprises a partition panel and a circuit board fastened to said partition panel, wherein the insertion results in an electrical connection of at least the electric motor and the circuit board, and 
     d) closing the housing base part with a housing cover. 
     Such a method is structurally simple and can therefore be implemented in a rapid and cost-effective manner. In this connection, the driven shaft of the electric motor is again aligned substantially perpendicularly to the partition panel and to the circuit board. 
     Moreover, a plug-connector half can be integrally provided on the housing and the plug-connector half can be electrically connected to the circuit as a result of inserting the control assembly into the housing base part. This takes place without additional effort during the insertion of the control assembly. 
     In one exemplary arrangement, the circuit board is electrically connected to the electric motor and/or the plug-connector half by forming an electrical press connection or an electrical insulation displacement connection. The electrical contacting therefore takes place without further activity during the insertion of the corresponding assembly. Therefore, the electrical contacting does not require additional effort. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The disclosure is explained below with reference to an exemplary arrangement, which is shown in the accompanying drawings, in which: 
         FIG.  1    shows an exemplary actuator assembly, which has been manufactured by a method for manufacturing an actuator assembly, in a perspective exploded illustration, 
         FIG.  2    shows a drive assembly of the actuator assembly of  FIG.  1    in an isolated, partially sectional illustration, 
         FIG.  3    shows the actuator assembly of  FIG.  1    in a sectional view in the plane III of  FIG.  1   , wherein a brake calliper assembly is connected to the actuator assembly, 
         FIG.  4    shows the actuator assembly of  FIG.  3    in a view along the section line IV-IV, wherein a spindle drive of the actuator assembly is not illustrated, 
         FIG.  5    shows a carrier assembly of the drive assembly of  FIG.  2    in a perspective exploded illustration, 
         FIG.  6    shows the drive assembly of  FIG.  2    in a rear view, wherein a spindle drive is not illustrated, 
         FIG.  7    shows a detailed view of a locking assembly of the actuator assembly of  FIGS.  1  to  6   , wherein the locking assembly assumes a locking state, 
         FIG.  8    shows a detailed view, corresponding to  FIG.  7   , of the locking assembly, wherein the locking assembly assumes a release state, 
         FIG.  9    shows a control assembly of the actuator assembly of  FIG.  1    in a perspective exploded illustration, and 
         FIG.  10    shows the control assembly of  FIG.  9    in a view along the direction X in  FIG.  9   . 
     
    
    
     DETAILED DESCRIPTION 
       FIG.  1    shows an actuator assembly  10  for a vehicle brake. 
     The actuator assembly  10  comprises a control assembly  12 , which can be installed as a separate sub-unit, and a drive assembly  14 , which can be installed as a separate sub-unit. 
     The control assembly  12  and the drive assembly  14  are arranged in a common housing  16 . 
     The housing  16  comprises a substantially shell-shaped housing base part  18  and a housing cover  20 , by which the housing base part  18  is tightly dosed in the installed state. 
     In the illustrated exemplary arrangement, the housing cover  20  is also substantially shell-shaped. 
     Both the housing base part  18  and the housing cover  20  are manufactured from plastic material. The housing  16  in its entirety is therefore made of plastic material. 
     The drive assembly  14  can be seen in detail in  FIGS.  2  to  6   . 
     The drive assembly  14  comprises a carrier assembly  22 , which has a plate-shaped frame part  24  (see for example  FIGS.  2  and  5   ). 
     A first fastening interface  26 , to which an electric motor  28  is fastened in the illustrated exemplary arrangement, is provided on the plate-shaped frame part  24 . 
     For example, the electric motor  28  is connected to the frame part  24  in a captive manner via the first fastening interface  26 . To this end, a bore  30 , via which the electric motor  28  can be fastened to the frame part  24  by a fastener, such as a screw (see  FIGS.  4  and  5   ), is provided on the frame part  24 . 
     Moreover, a centring device  32  in the form of a centring surface is arranged on the frame part  24 . The electric motor  28  can therefore be fastened to the frame part  24  in a centred manner with respect to a centre axis  34  of the first fastening interface  26 . 
     Moreover, an anti-rotation device  36  in the form of an anti-rotation depression is provided, which is designed to prevent the electric motor  28  from rotating with respect to the frame part  24 . 
     To introduce a torque into the drive assembly  14 , a driven gearwheel  40  is arranged on a driven shaft  38  of the electric motor  28 . 
     A bearing pin  42  is moreover provided on the frame part  24 , on which bearing pin a gearwheel  44 , which meshes with the driven gearwheel  40 , is mounted in the illustrated exemplary arrangement. 
     Moreover, a receiving space  46  for a planetary gear stage  48  is provided on the frame part  24 . In the illustrated exemplary arrangement, the receiving space  46  is substantially bell-shaped (see in particular  FIG.  5   ). 
     In this case, a centre axis  50  of the receiving space  46  is arranged substantially parallel to the centre axis  34  of the first fastening interface  26 . 
     A reinforcing part  52  is furthermore fastened to the frame part  24  in such a way that it spans the receiving space  46  at the axial end face with respect to the centre axis  50 . 
     In the illustrated exemplary arrangement, the reinforcing part  52  is substantially cross-shaped. 
     A bearing point  54  for a gearwheel  56  is moreover provided on the reinforcing part  52 , which gearwheel is arranged coaxially to the planetary gear stage  48 . 
     The gearwheel  56  meshes with the gearwheel  44 . 
     A gear train  58  is thus formed by the gearwheel  44  and the gearwheel  56 , as the input element of said gear train operates the driven gearwheel  40 . 
     The gearwheel  56  is furthermore formed in one piece with a sun wheel  60  of the planetary gear stage  48 . The gear train  58  and the planetary gear stage  48  are thus drivingly coupled. 
     The planetary gear stage  48  moreover comprises a ring gear  62 , which extends substantially along an inner circumference of the receiving space  46  (see for example  FIG.  5   ). 
     In the illustrated exemplary arrangement, a total of three planetary gears  64  are drivingly provided between the sun wheel  60  and the ring gear  62 . These planetary gears are rotatably mounted on a planetary carrier  66 . 
     In this case, the planetary carrier  66  represents a driven element of the planetary gear stage  48 . 
     The gear train  58  and the planetary gear stage  48  are also referred to collectively as a gear unit  67 . 
     The frame part  24  moreover has a second fastening interface  68 , which is designed for fastening a bearing sleeve  70  for a spindle drive  72 . 
     In this case, a centre axis of the second fastening interface  68  coincides with the centre axis  50  of the receiving space  46  and is therefore denoted by the same reference sign. 
     The second fastening interface  68  has an anti-rotation geometry  74 , which extends circumferentially around the centre axis  50  and is formed by a plurality of radial projections  76  and radial depressions  78  arranged circumferentially in an alternating manner. For better clarity, only one exemplary radial projection  76  and one exemplary radial depression  78  are denoted by a reference sign in each case in  FIGS.  5  and  6   . 
     The radial projections  76  and the radial depressions  78  are provided at a constant spacing. This means that the radial depressions  78  each have the same length in the circumferential direction. The radial projections  76  also each have the same length in the circumferential direction. A radial height of the radial projections  76  is moreover constant. 
     An anti-rotation device  80  of the second fastening interface  68  is thus formed. 
     On that end of the bearing sleeve  70  which is to be coupled to the second fastening interface  68 , a complementary geometry  82  is provided so that the bearing sleeve  70  can be inserted into the anti-rotation geometry  74  of the second fastening interface  68  along the centre axis  50  and is held therein in a torsion-resistant manner. 
     The spindle drive  72  is received in the interior of the bearing sleeve  70 . 
     This spindle drive comprises a spindle  84 , which, in the present exemplary arrangement, is configured as a ball screw (see for example  FIG.  2   ). 
     In this case, the spindle  84  is connected to the planetary carrier  66  in a torsion-resistant manner via the toothed portion  86 . 
     The spindle drive  72  can therefore be driven by the electric motor  28 . In detail, the electric motor  28  is drivingly coupled to the spindle drive  72  via the gear train  58  and the planetary gear stage  48 . 
     A spindle nut  88 , which is configured in the shape of a piston, is mounted on the spindle  84 . In this case, a rotation of the spindle  84  brings about an axial displacement of the spindle nut  88  along the centre axis  50 . 
     In this case, the spindle nut  88  is guided along the centre axis  50  via a linear guiding geometry  90  on the bearing sleeve  70 . The linear guiding geometry  90  corresponds substantially to a cylinder lateral surface which forms the inner circumference of the bearing sleeve  70 . 
     The spindle nut  88  is furthermore prevented from performing a relative rotation around the centre axis  50  by an anti-rotation device  92 , which is designed as an elongated hole in the bearing sleeve  70 . To this end, a radial projection  94  is attached to the spindle nut  88 , which radial projection engages in the elongated hole (see  FIG.  3   ). 
     The spindle nut  88  moreover serves as an actuating slide for a first brake pad  96  of a brake calliper assembly  98  (see  FIG.  3   ). Since the spindle nut  88  and the actuating slide are formed by the same component, they are denoted by the same reference sign. 
     The first brake pad  96  can therefore be actively moved towards a brake rotor  100  by the actuator assembly  10 , which brake rotor is designed as a brake disc in the illustrated exemplary arrangement. 
     In detail, by the electric motor  28 , the actuating slide  88  is optionally transferred to an extended position via the gear train  58 , the planetary gear stage  48  and the spindle drive  72 , which extended position is associated with the first brake pad  96  being applied to the brake rotor  100 . 
     Owing to the reaction forces acting within the actuator assembly  100  and the brake calliper assembly  98 , a second brake pad  102  is thus also applied to the brake rotor  100  (again, see  FIG.  3   ). 
     It goes without saying that, through the operation of the electric motor  28 , the actuating slide  88  can be moved into a retracted position in the same way, which retracted position is associated with the first brake pad  96  and the second brake pad  102  being lifted off the brake rotor  100 . 
     In the present exemplary arrangement, however, the actuating assembly  10  is designed without self-locking, so that the actuating slide  88 , owing to the elasticities inherent to the system, is also automatically moved back into the retracted position when it is no longer actively forced into the extended position by the electric motor  28 . 
     A third fastening interface  104  is moreover provided on the frame part  24  (see for example  FIG.  6   ). 
     This fastening interface is designed for fastening a locking assembly  106 , wherein the locking assembly  106  is in turn provided for optionally blocking the driven shaft  38  of the electric motor  28  in terms of rotation. 
     In this connection, the third fastening interface  104  comprises a bearing pin  108  fastened to the frame part  24  and a fastening interface  110  for a locking actuator  112 . 
     The locking assembly  106  is equipped with a locking lever  114 , which has a first, forked end  116 , which receives the bearing pin  108  for rotatably mounting the locking lever  114 . 
     The locking lever  114  is therefore rotatably mounted on the carrier assembly  22 , and more precisely on the frame part  24 , at its first end  116 . 
     At a second, opposite end  118  of the locking lever  114 , this is coupled to the locking actuator  112  via an elongated hole  120 . 
     In the illustrated exemplary arrangement, the locking actuator  112  is designed as a bistable lifting magnet. 
     This means that an armature  122  of the locking actuator  112  can be held both in its extended position and in its retracted position in the de-energised state (see  FIGS.  7  and  8   ). The locking actuator  112  only needs to be energised to move the armature  122  between these two positions. 
     A locking tooth  124  is furthermore positioned between the first end  116  and the second end  118  as seen in a direction along the longitudinal extent of the locking lever  114 . 
     This locking tooth is formed in one piece with the locking lever  114 . 
     The toothing of the driven gearwheel  40  moreover acts as a locking contour. 
     The locking tooth  124  can therefore be optionally brought into engagement with the locking contour through the actuation of the locking actuator  112 . 
     If the locking tooth  124  therefore engages in the driven gearwheel  40 , the electric motor  28  is therefore blocked in terms of rotation (see  FIG.  7   ). Such a position of the locking assembly  106  is also referred to as a locking position or locking state. 
     If the locking tooth  124  is located outside the toothing of the driven gearwheel  40 , this gearwheel can be freely rotated. Such a position of the locking assembly  106  is referred to as a release position (see  FIG.  8   ). 
     The locking lever  114  furthermore has a supporting projection  126  in the direction along its longitudinal extent between the first end  116  and the second end  118 , the flank  128  of which supporting projection forms a supporting contour  129 . 
     The supporting projection  126  is also formed in one piece on the locking lever  114 . 
     In this case, the flank  128  lies against a bearing contour  132 , which is formed as an arcuate wall portion  130  of the frame part  24 , i.e. of the carrier assembly  22 , in a substantially radial direction with respect to the bearing pin  108 . 
     In this case, a lateral surface of the arcuate wall portion  130 , which faces the flank  128 , is designed as a lateral cylinder surface portion of a circular cylinder, whereof the centre axis coincides with a centre axis of the bearing pin  108 . 
     The flank  128  is likewise designed as a lateral cylinder surface portion of such a circular cylinder. 
     By way of the supporting projection  126  and the bearing contour  132 , the locking lever  114  is therefore supported on the frame part  24 , i.e. on the carrier assembly, against forces which act substantially radially with respect to the rotational bearing of the locking lever  114  around the bearing pin  108 . 
     In the locking state, such force components result from a torque which is applied to the driven gearwheel  40 , for example. 
     The bearing contour  132  can therefore also be regarded as part of the third fastening interface  104 . 
     To enable its engagement in the driven gearwheel  40  for the purpose of blocking a rotational movement of the electric motor  28  without simultaneously obstructing a meshing between the driven gearwheel  40  and the gearwheel  44 , the locking lever  114  has a first portion  114   a  in the direction along its longitudinal extent, which portion comprises the first end  116 . A second portion  114   b  comprises the second end  118 . 
     In this case, the second portion  114   b  is offset relative to the first portion  114   a  along the centre axis  34  in the direction of the electric motor  28 . It may also be said that the locking lever  114  has a headless design. 
     It is thus possible that the second portion  114   b  extends behind the gearwheel  44  as seen in the axial direction. 
       FIGS.  9  and  10    show the control assembly  12  in detail. 
     This control assembly comprises a partition panel  134  which, in the illustrated exemplary arrangement, is provided with an edge  136  which extends substantially entirely along an outer circumference of the partition panel  134 . 
     The partition panel  134  can therefore also be referred to as a partition compartment. 
     The control assembly  12  furthermore comprises a circuit board  138  on which electrical and electronic components (denoted as a whole by  140 ) are arranged and electrically connected to one another via traces. 
     In this case, the electrical and electronic components  140  form a speed regulating unit for regulating a speed of the electric motor  28 . 
     The electrical and electronic components  140  furthermore form a current measuring unit for measuring a current received by the electric motor  28 . 
     The electrical and electronic components  140  moreover represent a current supply unit for supplying the electric motor  28  with electric energy. In this connection, the electrical and electronic components  140  can also be referred to as power electronics. 
     Moreover, the electrical and electronic components  140  form a temperature measuring unit for measuring a temperature within the actuator assembly  10 . 
     A force measuring unit for measuring a brake actuating force provided by the actuator assembly is also created by the electrical and electronic components  140 . 
     The electrical and electronic components  140  furthermore represent an actuating unit for the locking assembly  106 . 
     In addition, a rotational position detection unit for detecting a rotational position of the electric motor  28  is formed by the electrical and electronic components  140 , which rotational position detection unit is explained in detail below. 
     In order to fasten the partition panel  134  and the circuit board  138  to one another in a predetermined relative position, a positioning and fastening arrangement  142  for the circuit board  138  are provided on the partition panel  134 . 
     In the exemplary arrangement illustrated in  FIG.  9   , the positioning and fastening arrangement  142  is formed by fastening domes, which are arranged on the partition panel  134  and into which screws  144 , which pass through the circuit board  138 , are screwed. 
     Moreover, the partition panel  134  and the circuit board  139  are connected to one another via a potting material  146 , which is illustrated merely schematically in an exemplary region. In one exemplary arrangement, a clearance which is present between the partition panel  134  and the circuit board  138  is filled substantially entirely with the potting material  146 . The electrical and electronic components  140  are thus protected against undesirable external influences, for example against vibrations and moisture. 
     The partition panel  134  and the circuit board  138  are arranged relative to the electric motor  28  such that the driven shaft  38  of the electric motor  28  is aligned perpendicularly to the partition panel  134  and to the circuit board  138 . 
     In this case, a magnet  148  is arranged at an end of the driven shaft  38  of the electric motor  28  which faces the control assembly  12  (see in particular  FIGS.  2  and  4   ). 
     An associated sensor  150  is positioned on the circuit board  138  at a point which is opposite the magnet  148  (see in particular  FIG.  4   ). 
     In the illustrated exemplary arrangement, the sensor  150  is designed as a Hall sensor. A rotational position of the driven shaft  38  of the electric motor  28  can thus be detected. When evaluating the rotational position signals over time, revolutions of the driven shaft  38  can also be determined. 
     In order to supply the control assembly  12  and in particular the electrical and electronic components  140  with electric energy, a plug-connector half  152  is integrally provided on the housing  16 , and more precisely on the housing base part  18  (see  FIGS.  1  and  4   ). 
     In this case, the plug-connector half  152  is electrically connected to the circuit board  138  via a plurality of lines which are collectively referred to as the first electric line  154 . 
     Starting from the plug-connector half  152 , the first electric line  154  firstly extends within the housing base part  18 . In this connection, the first electric line  154  can already be integrated in the housing base part  18  during the manufacture thereof. 
     In this case, a portion  154   a  of the first electric line  154  which is on the circuit-board side is designed to be dimensionally stable and protrudes from the housing base part  18  in a direction which is aligned substantially parallel to the centre axes  34  and  50 . 
     Contact openings  156  associated with the first electric line  154  are provided on the circuit board  138 . 
     A passage  158  is furthermore formed on the partition panel  134  so as to ensure that the portion  154   a  which is on the circuit-board side reaches the circuit board  138  without making contact with the partition panel  134 . 
     The passage  158  is moreover provided with an edge  160  so that the passage  158  is kept free of potting material  146 . 
     The first electric line  154 , and more precisely the portion  154   a  thereof which is on the circuit-board side, can therefore be plugged into the associated contact openings  156  during the installation of the control assembly  12  on the housing base part  18 . In this case, they form an electrical press contact. 
     In the illustrated exemplary arrangement, the plug-connector half  152  serves not only for supplying power, but also for connecting the actuator assembly  10  to a bus system, which is for example a CAN bus system. 
     Wheel speed sensors can furthermore be connected to the actuator assembly  10  via the plug-connector half  152 . 
     The electric motor  28  is also electrically connected to the circuit board  138 . 
     To this end, dimensionally stable contacts protrude from the electric motor  28  such that they are substantially parallel to the centre axis  34 , which contacts are collectively referred to as the second electric line  162 . 
     Contact openings  164  in the circuit board  138  are likewise associated with the second electric line  162 . 
     A passage  166  is furthermore provided on the partition panel  134 , through which passage the second electric line  162  can come into engagement with the contact openings  164 . 
     The passage  166  is again equipped with an edge  168 , so as to ensure that the passage  166  is kept free of potting material  146 . 
     As has already been explained with respect to the first electric line  154 , the second electric line  162  also enters the associated contact openings  164  during the installation of the control assembly  12  and forms an electrical press contact. 
     The locking actuator  112  is electrically connected to the circuit board  138  via a third electric line  170  (see  FIGS.  1  and  2   ). 
     In this case, the third electric line  170  is also again formed by dimensionally stable contacts, which protrude from the locking actuator  112  along the centre axes  34  and  50 . 
     Contact openings  172  in the circuit board  138  are again associated with the third electric line  170  (see  FIG.  9   ). 
     So that the third electric line  170  can be plugged into the contact openings  172 , a passage  174  is moreover provided on the partition panel  134 . This passage is equipped with an edge  176  so that the passage  174  is also kept free of potting material  146 . 
     As already explained with respect to the first electric line  154  and the second electric line  162 . the third electric line  170  is also inserted into the associated contact openings  172  during the installation of the control assembly  12  and forms an electrical press contact. 
     In summary, the circuit board  138  is therefore electrically coupled to the plug-connector half  152  as well as to the electric motor  28  and the locking actuator  112 . 
     On a side of the partition panel  134  which faces the drive assembly  14 , retaining ribs  178  are moreover provided in the region of the driven gearwheel  40  and the gearwheel  44 , which retaining ribs substantially form an enveloping end around a gear stage which is formed by the driven gearwheel  40  and the gearwheel  40 . 
     Retaining ribs  180  are also provided in the region of the planetary gear stage  48 . 
     In this case, the retaining ribs  178 ,  180  serve to keep a lubricating medium in the region of the gearwheels to be lubricated, even upon a rotation of the driven gearwheel  40 , the gearwheel  44  and the planetary gear stage  48 . 
     By the actuator assembly  10 , a service brake function can be provided when the actuator assembly  10  is coupled to the brake calliper assembly  98 . The actuator assembly  10  is then operated in service brake mode. In this case, the electric motor  28  is controlled by the control assembly  12  in such a way that it brings about a desired displacement of the spindle nut  88 —the actuating slide  88 —along the centre axis  50  via the gear train  58 , the planetary gear stage  48  and the spindle drive  72 . 
     In this case, the electric motor  28  can fundamentally be actuated in both directions of rotation so that the actuating slide  88  can also be actively displaced in both directions. 
     It is likewise conceivable to only use the electric motor  28  to move the actuating slide  88  into an extended position, i.e. to apply the brake pad  96  to the brake rotor  100 . 
     In this connection, the actuating slide  88  can be restored to a retracted position, i.e. the pressure on the brake pad  96  can be relieved, as a result of the elasticities which are inherent to the system on the one hand and the non-self-locking configuration of the actuator assembly  10  on the other. 
     In such an operating mode, the locking assembly  106  always assumes the release state (see  FIG.  8   ). 
     Moreover, a parking brake function can be provided by the actuator assembly  10 . 
     In this connection, a parking brake mode can be activated in that the spindle nut  88  (which forms the actuating slide  88 ) is transferred to its extended position by the electric motor  28  and the brake pad  96  is therefore applied to the brake rotor  100 . In this case, the brake pad  102  is also applied to the brake rotor  100  as a result of reaction forces which act within the actuator assembly  10 . 
     Finally, the locking assembly  106  is transferred to the locking state by the locking actuator  112  (see  FIG.  7   ). 
     Up to the point at which the locking tooth  124  actually engages in the toothing of the driven gearwheel  40  and therefore locks a rotation of the driven shaft  38 , the spindle nut  88  (which forms the actuating slide  88 ) is actively held in the extended position by the electric motor  28 , i.e. the electric motor  28  is energized accordingly. 
     A current supply to the electric motor  28  is only interrupted when the locking tooth  124  securely engages in the locking contour formed by the toothing of the driven gearwheel  40 . 
     There are a plurality of alternatives for deactivating the parking brake mode. 
     To this end, in one exemplary alternative, the electric motor  28  is actuated in a direction in which it forces the spindle nut  88  (which forms the actuating slide  88 ) into the extended position, i.e. it moves it in the direction of the brake pad  96 . 
     This relieves the force on the locking lever  114 . 
     The locking lever  114  can therefore be easily transferred from the locking position to the release position by the locking actuator  112  (see  FIGS.  7  and  8   ) 
     The energization of the electric motor  28  can then be stopped so that the spindle nut  88  automatically moves back into the retracted position due to the lack of a self-locking effect. 
     It is alternatively conceivable that, rather than the locking lever  114  being transferred to the release position as a result of an actuation of the locking actuator  112 , the electric motor  28  is instead actuated in a direction which corresponds to the extended position of the spindle nut  88  in such a way that the locking lever  114  is forced into its release position by the electric motor  28 . 
     The electric motor  28  can then be operated in a direction which is associated with the retracted position of the spindle nut  88  so that the parking brake mode is deactivated. 
     It goes without saying that it is also conceivable for the parking brake mode to be deactivated merely by actuating the locking lever  114  by the locking actuator  112 . In this alternative, the electric motor  28  is not used to deactivate the parking brake mode. However, the locking lever  144  may have to be switched under load. 
     The actuator assembly  10  can be manufactured as follows. 
     Firstly, the housing base part  18  is provided. 
     Then, the already pre-assembled drive assembly  14  is inserted into the housing base part  18 . 
     As already explained, the drive assembly  14  comprises the carrier assembly  22 , on which the electric motor  28 , the spindle drive  72  and the gear unit  67  is mounted, which gear unit drivingly couples the electric motor  28  and the spindle drive  72  and comprises the clear train  58  and the planetary gear stage  48 . 
     The control assembly  12  is then inserted into the housing base part  18 . 
     As already explained, the control assembly  12  comprises the partition panel  134  and the circuit board  138 . 
     As a result of inserting the control assembly  12  into the housing base part  18 , the electric motor  28  is moreover electrically connected to the circuit board via the second electric line  162 . 
     The plug-connector half  152  is furthermore electrically connected to the circuit board  138  via the first electric line  154 . 
     The locking actuator  112  is also connected to the circuit board  138  via the third electric line  170  during the insertion of the control assembly  12 . 
     In this case, the electrical connections are each formed in that the electric lines  154 ,  162 ,  170  are plugged into the respectively associated contact openings  156 ,  164 ,  172  to form an electrical press contact. 
     The housing base part  18  is finally closed by fitting the housing cover  20 .