Patent Publication Number: US-2023151860-A1

Title: Carrier assembly and drive assembly for an actuator assembly for a vehicle brake, and actuator assembly

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to German Priority Application No. 102021129954.3, filed Nov. 17, 2021, the disclosure of which is incorporated herein by reference in its entirety. 
     TECHNICAL FIELD 
     The disclosure relates to a carrier assembly for an actuator assembly for a vehicle brake. The disclosure furthermore concerns a drive assembly for an actuator assembly for a vehicle brake which has a carrier assembly of the type mentioned at the beginning. The disclosure moreover relates to an actuator assembly for a vehicle brake, with such a drive assembly, wherein the drive assembly is arranged in a housing. 
     BACKGROUND 
     Actuator assemblies, drive assemblies and support assemblies of the above described type are known from the prior art. Known support assemblies here serve to mount moved components of the drive assembly and position them inside the actuator assembly. The carrier assembly accordingly need to be designed to absorb reaction forces and reaction torques resulting from drive forces and drive torques. The carrier assembly therefore needs to have as stiff a design as possible. 
     Against this background, what is needed is to further improve known support assemblies and drive assemblies and actuator assemblies equipped therewith. 
     SUMMARY 
     What is needed is a carrier assembly is provided with relatively high stiffness. Accordingly a carrier assembly of the type mentioned at the beginning is herein described which comprises a plate-like frame part which has a receiving space for a planetary gear stage and a first fastening interface for an electric motor. A centre axis of the receiving space and a centre axis of the first fastening interface here run essentially parallel. In this context, the designation of the fastening interface as “first” is solely for the purpose of simple explanation. A number of fastening interfaces is not implied. Moreover, a frame part is understood to mean a self-contained component. The frame part, for example, is not formed by a portion of another component. The use of a plate-like frame part entails that the carrier assembly as a whole is very stiff. This is due to the fact that the planetary gear stage can be received on the same frame part on which the electric motor can also be fastened. The high stiffness of the frame part here also exists at high temperatures which can occur during the operation of the carrier assembly. Because the centre axis of the receiving space and the centre axis of the first fastening interface extend in parallel, the carrier assembly moreover has a compact structure. Thus only a relatively small amount of space is taken up on a vehicle in which the carrier assembly is used. 
     In one exemplary arrangement, the frame part comprises a metal material. For example, the frame part is made from a metal material and is accordingly produced from a metal material. 
     In one exemplary arrangement, the first fastening interface comprises an anti-rotation device. The electric motor can thus be mounted on the frame part only in one predetermined rotational position. Moreover, a torque generated by the electric motor is reliably supported on the frame part during operation. A torque generated by the electric motor can thus be exploited reliably and efficiently. 
     The first fastening interface can also comprise a centring device. The electric motor to be connected to the frame part via the first fastening interface is thus mounted on the frame part in a centring fashion, A torque generated by the electric motor can consequently be imparted accurately to an actuator assembly equipped with the carrier assembly. 
     According to an exemplary arrangement, the receiving space is generally cylindrical or bell-shaped. A generally cylindrical receiving space here has a generally circular base. In this context, a cylinder centre axis coincides with the centre axis of the receiving space. In contrast to a generally cylindrical receiving space, a generally bell-shaped receiving space tapers along its centre axis. When viewed in the circumferential direction, an outer surface of the receiving space can be domed or curved. In a special case, a generally bell-shaped receiving space has a frustoconical design. When viewed in the circumferential direction, an outer surface then runs generally in a straight line. Receiving spaces of this type are well suited for receiving planetary gear stages without undesired cavities being thus formed. A compact structure of an actuator assembly equipped with the carrier assembly is thus ensured. 
     The frame part can also have a second fastening interface for a bearing sleeve for a spindle drive. A centre axis of the second fastening interface here generally coincides with the centre axis of the receiving space. The designation of the fastening interface as “second” is again solely for the purpose of simple explanation. A number of fastening interfaces is furthermore not implied. A spindle drive can thus be mounted on the frame part via the second fastening interface and the mounting sleeve. Reaction forces and reaction torques resulting from the operation of the spindle drive can consequently also be absorbed reliably by the frame part. The coaxial arrangement of the second fastening interface and the receiving space for the planetary gear stage result in a compact structure of an actuator assembly equipped with the carrier assembly. 
     In one exemplary arrangement, the second fastening interface comprises an anti-rotation device. Torques imparted to the bearing sleeve can consequently be supported simply and reliably on the frame part. 
     According to another exemplary arrangement, the anti-rotation device has an anti-rotation geometry which runs circumferentially around the centre axis of the second fastening interface and has a plurality of radial projections and radial depressions arranged alternately over the circumference. The radial projections and radial depressions are here provided with a constant pitch. A bearing sleeve equipped with a complementary geometry can thus be plugged simply into the anti-rotation geometry along the centre axis of the second fastening interface. The radial projections and radial depressions with a constant pitch here form a pattern with respect to the rotational position of the bearing sleeve. The latter can thus be fastened on the frame part in a large number of rotational positions predetermined by the pitch. 
     A bearing sleeve for a spindle drive can thus be connected to the frame part via the second fastening interface. In one exemplary arrangement, the bearing sleeve is plugged into the fastening interface along the centre axis of the latter. The already mentioned effects and advantages result. 
     In an alternative, the bearing sleeve has a linear guide geometry, acting along the centre axis of the second fastening interface, for a spindle nut. A spindle nut which can be shifted along the centre axis of the second fastening interface can thus be received in the bearing sleeve. It can be used to move a brake lining. 
     The bearing sleeve can also comprise an anti-rotation device for the spindle nut. A spindle nut received in the bearing sleeve can therefore not rotate relative to the bearing sleeve. The spindle nut is thus moved reliably and efficiently along the centre axis of the second fastening interface. 
     In one exemplary arrangement, a reinforcing part which axially spans the end of the receiving space at least partially is fastened to the frame part. The reinforcing part can in principle assume any desired shape. It is, however, in the form of a cross-piece or is cross-shaped. The reinforcing component further increases the stiffness of the frame part. Furthermore, the reinforcing part can also serve to mount drive elements, for example gear wheels. 
     In an alternative exemplary arrangement, at least one journal for a gear wheel is arranged on the frame part. At least one gear wheel can thus be mounted on the frame part. Reaction forces resulting from the operation of the gear wheel are reliably absorbed at the frame part as a result. 
     The frame part can also have a third fastening interface for a locking assembly for selectively immobilizing a drive shaft of the electric motor in rotation. The designation of the fastening interface as “third” is again solely for the purpose of simpler explanation. A number of fastening interfaces is furthermore not implied. The locking assembly can thus be mounted reliably on the frame part via the third fastening interface. As before, reaction forces and reaction torques resulting from the operation of the locking assembly are here absorbed by the frame part. Furthermore, a compact structure thus results. 
     In summary, the carrier assembly according to the disclosure is designed to receive all the components of a drive assembly for an actuator assembly. 
     In addition, a drive assembly of the type mentioned at the beginning which comprises a carrier assembly according to the disclosure. A planetary gear stage is here arranged in the receiving space. An electric motor is fastened to the first fastening interface. Moreover, at least one journal, on which a gear wheel of a gear train is mounted, is arranged on the frame part. A bearing sleeve for a spindle drive is fastened to a second fastening interface of the frame part, wherein a spindle drive is mounted on the carrier assembly by the bearing sleeve. The electric motor is thus coupled to the spindle drive drivingly via the at least one gear wheel of the gear train and the planetary gear stage. This drive assembly is configured as a separately mountable subassembly of an actuator assembly for a vehicle brake. All the essential drive components are here mounted on the carrier assembly. The drive assembly can thus, when producing an actuator assembly, be premounted separately from further components of the actuator assembly. Forces and torques which occur during operation are supported on the frame part either directly or via the bearing sleeve. The support is thus effected in particular not via mounting interfaces of different components. The drive assembly is thus relatively stiff. 
     In one exemplary arrangement, the drive assembly is designed so that it is not self-locking. This means that the spindle nut can shift back from its extended position into its retracted position by virtue of an axially acting compressive force without actuating the electric motor. 
     The effects and advantages already explained with respect to the carrier assembly also apply in the same way for the drive assembly, and vice versa. 
     An actuator assembly of the type mentioned at the beginning which comprises a drive assembly according to the disclosure. The high stiffness of the carrier assembly also applies in the actuator assembly. For this reason, the actuator assembly can be operated efficiently. This is because, by virtue of the high stiffness, the proportion of drive energy which flows undesirably in a deformation of the carrier assembly is relatively small. A large proportion of drive energy is thus available for actuating the actuator assembly. Furthermore, the responsiveness of the brake is improved by the high stiffness. A desired braking action can thus be set relatively quickly. An antilock braking system can consequently also be operated with increased accuracy and reliability. 
     Otherwise, the effects and advantages already explained with respect to the carrier assembly and the drive assembly also apply for the actuator assembly, and vice versa. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The disclosure is explained below with the aid of an exemplary arrangement which is shown in the attached drawings, in which: 
         FIG.  1    shows an actuator assembly according to the disclosure with a drive assembly according to the disclosure and a carrier assembly according to the disclosure in a perspective exploded view, 
         FIG.  2    shows the drive assembly from  FIG.  1    in an isolated, partially cut-away view. 
         FIG.  3    shows the actuator assembly from  FIG.  1    in a view in section in the plane Ill of  FIG.  1   , wherein a brake calliper is connected to the actuator assembly, 
         FIG.  4    shows the actuator assembly from  FIG.  3    in a view along the line of section IV-IV, wherein a spindle drive of the actuator assembly is not illustrated, 
         FIG.  5    shows the carrier assembly of the drive assembly from  FIG.  2    in a perspective exploded view, 
         FIG.  6    shows the drive assembly from  FIG.  2    in a rear view, wherein a spindle drive is not illustrated, 
         FIG.  7    is a detailed view of a locking assembly of the actuator assembly from  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 from  FIG.  1    in a perspective exploded view, and 
         FIG.  10    shows the control assembly from  FIG.  9    in a view in 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 mounted as a separate subunit and a drive assembly  14  which can be mounted as a separate subunit. 
     The control assembly  12  and the drive assembly  14  are arranged in a common housing  16 . 
     The housing  16  comprises an essentially shell-shaped housing base part  18  and a housing cover  20  by which the housing base part  10  is tightly closed in the mounted state. 
     In the exemplary arrangement illustrated, the housing cover  20  is also generally shell-shaped. 
     In one exemplary arrangement, both the housing base part  18  and the housing cover  20  are produced from plastic material. The housing  16  as a whole is thus made from 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-like frame part  24  (see in particular  FIGS.  2  and  5   ). 
     A first fastening interface  26 , at which an electric motor  28  is fastened in the exemplary arrangement illustrated, is provided at the plate-like frame part  24 . 
     To be more precise, the electric motor  22  is connected captively to the frame part  24  via the first fastening interface  26 . For this purpose, a bore  30 , via which the electric motor  28  can be fastened to the frame part  24  by a fastener, such as a screw, is provided on the frame part  24  (see  FIGS.  4  and  5   ). 
     Furthermore, a centring device  32  in the form of a centring surface is arranged on the frame part  24 . The electric motor  28  can thus be fastened to the frame part  24  such that it is centred with respect to a centre axis  34  of the first fastening interface  26 . 
     In addition, 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 relative to the frame part  24 . 
     An output gear wheel  40  is arranged on an output shaft  38  of the electric motor  28  in order to impart torque to the drive assembly  14 . 
     Furthermore, a journal  42 , on which in the exemplary arrangement illustrated a gear wheel  44  is mounted which meshes with the output gear wheel  40 , is provided on the frame part  24 . 
     Moreover, a receiving space  46  for a planetary gear stage  48  is provided on the frame part  24 . In the exemplary arrangement illustrated, the receiving space  46  is generally bell-shaped (see for example  FIG.  5   ). 
     A centre axis  50  of the receiving space  46  is here arranged generally parallel to the centre axis  34  of the first fastening interface  26 . 
     A reinforcing part  52  is moreover fastened to the frame part  24  in such a way that it axially spans the end of the receiving space  46  with respect to the centre axis  50 . 
     In the exemplary arrangement illustrated, the reinforcing part is generally cross-shaped. 
     In addition, a bearing point  54  for a gear wheel  56  arranged coaxially with the planetary gear stage  48  is provided on the reinforcing part  52 . 
     The gear wheel  56  meshes with the gear wheel  44 . 
     A gear train  58  is consequently formed by the gear wheel  44  and the gear wheel  56 , the output gear wheel  40  acting as its input member. 
     The gear wheel  56  is moreover formed integrally with a sun gear  60  of the planetary gear stage  48 . In this way, the gear train  58  and the planetary gear stage  48  are coupled drivingly. 
     The planetary gear stage  48  moreover comprises a ring gear  62  which runs generally along an inner circumference of the receiving space  46  (see in particular  FIG.  5   ). 
     In the exemplary arrangement illustrated, a total of three planetary gears  64  are provided drivingly between the sun gear  60  and the ring gear  62 . They are mounted rotatably on a planet carrier  66 . 
     The planet carrier  66  here represents an output element of the planetary gear stage  48 . 
     The gear train  58  and the planetary gear stage  48  are also referred to together as a gear unit  67 . 
     The frame part  24  furthermore has a second fastening interface  68  which is designed for fastening a bearing sleeve  70  for a spindle drive  72 . 
     A centre axis of the second fastening interface  68  here coincides with the centre axis  50  of the receiving space  46  and for this reason is provided with the same reference numeral. 
     The second fastening interface  68  has an anti-rotation geometry  74 , which is formed by a plurality of radial projections  76  and radial depressions  78  arranged alternately over the circumference, which runs circumferentially around the centre axis  50 , For reasons of greater visibility, in each case only one exemplary radial projection  76  and one exemplary radial depression  78  have been provided with a reference numeral in  FIGS.  5  and  6   . 
     The radial projections  76  and the radial depressions  78  are provided with a constant pitch. 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. Furthermore, a radial height of the radial projections  76  is constant. 
     In this way, an anti-rotation device  80  of the second fastening interface  68  is formed. 
     A complementary geometry  82  is provided at that end of the bearing sleeve  70  which is to be coupled to the second fastening interface  68  such that the bearing sleeve  70  can be pushed along the centre axis  50  into the anti-rotation geometry  74  of the second fastening interface  68  and held there non-rotatably. 
     The spindle drive  72  is accommodated inside the bearing sleeve  70 . 
     It comprises a spindle  84  which is configured in the present case as a ball screw (see in particular  FIG.  2   ). 
     The spindle  84  is here connected non-rotatably to the planet carrier  66  via the toothed section  86 . 
     The spindle drive  72  can thus be driven by the electric motor  28 . In detail, the electric motor  28  is coupled to the spindle drive  72  drivingly via the gear train  58  and the planetary gear stage  48 . 
     A spindle nut  88 , which is configured as a piston, is mounted on the spindle  84 . Rotation of the spindle  84  thus causes the spindle nut  88  to be shifted axially along the centre axis  50   
     The spindle nut  88  is here guided along the centre axis  50  on the bearing sleeve  70  by a linear guide geometry  90 . The linear guide geometry  90  corresponds essentially to a cylindrical surface forming the inner circumference of the bearing sleeve  70 . 
     The spindle nut  88  is moreover prevented from rotating relatively about the centre axis  50  by an anti-rotation device  92  which in one exemplary arrangement, is designed as a slot on the bearing sleeve  70 . For this purpose, radial extension  94  which engages in the slot (see  FIG.  3   ) is attached to the spindle nut  88 . 
     The spindle nut  88  furthermore serves as an actuating carriage for a first brake lining  96  of a brake calliper assembly (see  FIG.  3   ). Since the spindle nut  88  and the actuating carriage are formed by the same component, they are provided with the same reference numeral. 
     The first brake lining  96  can therefore be moved actively onto a brake rotor  100 , which in the exemplary arrangement illustrated is designed as a brake disc, by the actuator assembly  10 . 
     In detail, the actuating carriage  88  is transferred selectively into an extended position, which is associated with the application of the first brake lining  96  to the brake rotor  100 , by the electric motor  28  via the gear train  58 , the planetary gear stage  48  and the spindle drive  72 . 
     Because of the reaction forces acting inside the actuator assembly  10  and the brake calliper assembly  98 , a second brake lining  102  is consequently also applied to the brake rotor  100  (see again  FIG.  3   ). 
     It should be understood that the actuating carriage  88  can be moved in the same way by operation of the electric motor  28  into a retracted position which is associated with lifting the first brake lining  96  and the second brake lining  102  off the brake rotor  100 . 
     In the present case, however, the actuator assembly  10  is designed so that it is not self-locking, such that the actuating carriage  88  also shifts back automatically into the retracted position by virtue of elasticities inherent in the system when it is no longer actively forced into the extended position by the electric motor  28 . 
     A third fastening interface  104  is furthermore provided on the frame part  24  (see in particular  FIG.  6   ). 
     It is designed for fastening a locking assembly  106 , wherein the locking assembly  106  is in turn provided for selectively immobilizing the output shaft  38  of the electric motor  28  with respect to rotation. 
     In this context, the third fastening interface  104  comprises a bearing bolt  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 fork-shaped end  116  which receives the bearing bolt  108  for the rotational mounting of the locking lever  114 . 
     The locking lever  114  is thus mounted on the carrier assembly  22 , to be more precise on the frame part  24 , so that it can rotate at its first end  116 . 
     The locking lever  114  is coupled at the second opposite end of the latter to the locking actuator  112  via a slot  120 . 
     In the exemplary arrangement illustrated, the locking actuator  112  is configured as a bistable solenoid. 
     This means that an armature  122  of the locking actuator  112  can be held in both its extended position and in its retracted position without being supplied with current (see  FIGS.  7  and  8   ). The locking actuator  112  needs to be supplied with current only in order to shift the anchor  122  between these two positions. 
     A ratchet  124  is moreover positioned in the longitudinal direction of the extent of the locking lever  114 , between the first end  116  and the second end  118 . 
     It is formed as a single piece with the locking lever  114 . 
     The teeth of the output gear wheel  40  additionally acts as a locking contour. 
     The ratchet  124  can thus be selectively brought into engagement with the locking contour by actuating the locking actuator  112 . 
     In the event that the ratchet  124  thus engages in the output gear wheel  40 , the electric motor  28  is immobilized with respect to rotation (see  FIG.  7   ). Such a position of the locking assembly  106  is also referred to as a locking position or locking state. 
     When the ratchet  124  is situated outside the teeth of the output gear wheel  40 , the latter can be rotated freely. Such a position of the locking assembly  106  is referred to as the release position (see  FIG.  8   ). 
     In the longitudinal direction of its extent, the locking lever  114  moreover has, between the first end  116  and the second end  118 , a support projection  126 , the flank  128  of which forms a support contour  129 . 
     The support projection  126  is also integrally formed on the locking lever  114 . 
     The flank  128  here bears, in an essentially radial direction with respect to the bearing bolt  108 , against a bearing contour  132  formed as a curved wall section  130  of the frame part  24 , i.e. of the carrier assembly  22 . 
     A lateral surface, facing the flank  128 , of the curved wall section  130  is here formed as a cylindrical surface section of a circular cylinder, the centre axis of which coincides with a centre axis of the bearing bolt  108 . 
     The flank  128  is likewise formed as a cylindrical surface section of such a circular cylinder. 
     The locking lever  114  is therefore supported, via the support projection  126  and the bearing contour  132 , with respect to such force components on the frame part  24 , i.e. on the carrier assembly  22 , which act essentially radially with respect to its rotational mounting about the bearing bolt  108 . 
     Such force components result in the locking state, for example, from a torque present at the output gear wheel  40 . 
     The bearing contour  132  can thus also be considered as a constituent part of the third fastening interface  104 . 
     In order to be able to engage in the output gear wheel  40  for the purpose of immobilizing rotational movement of the electric motor  28 , but at the same time not impede meshing of the output gear wheel  40  with the gear wheel  44 , the locking lever  114  has, in the direction of its longitudinal extent, a first section  114   a  which comprises the first end  116 . A second section  114   b  comprises the second end  118 . 
     The second section  114   b  is here offset along the centre axis  34  with respect to the first section  114   a  in the direction of the electric motor  28 . It is also possible to describe the locking lever  114  as having a cranked design. 
     It thus becomes possible for the second section  114   b  to run behind the gear wheel  44 , viewed in the axial direction. 
       FIGS.  9  and  10    show the control assembly  12  in detail. 
     It comprises a bulkhead wall  134  which is provided in the embodiment illustrated with a peripheral rim  136  which runs essentially completely around the outer periphery of the bulkhead wall  134 . 
     The bulkhead wall  134  can thus also be referred to as a bulkhead tray. 
     The control assembly  12  moreover comprises a printed circuit board  138  on which electrical and electronic components designated as a whole by  140  are arranged and are connected to one another electrically via traces. 
     The electrical and electronic components  140  here form a speed-regulating unit for regulating the speed of the electric motor  28 . 
     A current measuring unit for measuring a current received by the electric motor  28  is moreover constructed from the electrical and electronic components  140 . 
     The electrical and electronic components  140  furthermore represent a current supply unit for supplying electrical energy to the electric motor  28 . In this connection, the electrical and electronic components  140  can also be referred to as a power electronic system. 
     The electrical and electronic components  140  moreover form a temperature measuring unit for measuring a temperature within the actuator assembly  10 . 
     A force measuring unit for measuring a brake actuating force supplied by the actuator assembly is also provided by the electrical and electronic components  140 . 
     The electrical and electronic components  140  moreover represent a control unit for the locking assembly  106 . 
     A rotational position detection unit for identifying a rotational position of the electric motor  28  is additionally formed from the electrical and electronic components  140  and is explained in more detail below. 
     In order to fasten the bulkhead wall  134  and the printed circuit board  138  against each other in a predetermined relative position, means  142  for positioning and fastening the printed circuit board  138  are provided on the bulkhead wall  134 . 
     In the exemplary arrangement illustrated in  FIG.  9   , the arrangement  142  for positioning and fastening are formed by fastening domes arranged on the bulkhead wall  134  and into which screws  144  are screwed which extend through the printed circuit board  138 . 
     The bulkhead wall  134  and the printed circuit board  138  are furthermore connected to each other via a potting material  146  illustrated only schematically in an exemplary region. An intermediate space present between the bulkhead wall  134  and the printed circuit board  138  is here filled by the potting material  146 . In this way, the electrical and electronic components  140  are protected from undesired external influences, in particular from vibrations and moisture. In the exemplary arrangement shown, the potting material generally completely fills the intermediate space. 
     The bulkhead wall  134  and the printed circuit board  138  are arranged relative to the electric motor  28  such that the output shaft  38  of the electric motor  28  is oriented perpendicular to the bulkhead wall  134  and to the printed circuit board  138 . 
     A magnet  148  is here arranged at an end, facing the control assembly  12 , of the output shaft  38  of the electric motor  28  (see in particular  FIGS.  2  and  4   ). 
     An associated sensor  150  is positioned on the printed circuit board  138  at a location situated opposite the magnet  148  (see in particular  FIG.  4   ). 
     The sensor  150  takes the form of a Hall effect sensor in the exemplary arrangement illustrated. In this way, a rotational position of the output shaft  38  of the electric motor  28  can be detected. Revolutions of the output shaft  38  can also be determined when evaluating the rotational position signals over time. 
     In order to supply the control assembly  12  and in one exemplary arrangement, the electrical and electronic components  140  with electrical energy, a plug connector half  152  is provided integrally on the housing  16 , to be more precise on the housing base part  18  (see  FIGS.  1  and  4   ). 
     The plug connector half  152  is here electrically connected to the printed circuit board  138  via a plurality of lines which are referred to collectively as a first electrical line  154 . 
     Starting from the plug connector half  152 , the first electrical line  154  runs initially inside the housing base part  18 . In this connection, the first electrical line  154  can be integrated into the housing base part  18  when the latter is produced. 
     A section  154   a , on the printed circuit board side, of the first electrical line  154  is here designed as dimensionally stable and protrudes from the housing base part  18  in a direction which is oriented generally parallel to the centre axes  34  and  50 . 
     Contact openings  156  associated with the first electrical line  154  are provided on the printed circuit board  138 . 
     A passage  158  is moreover formed on the bulkhead wall  134  such that it is ensured that the section  154   a , on the printed circuit board side, reaches the printed circuit board  138  without contacting the bulkhead wall  134 . 
     The passage  158  is additionally provided with a rim  160  such that the passage  158  is kept free of potting material  146 . 
     When the control assembly  12  is mounted on the housing base part  18 , the first electrical line  154 , to be more precise its section  154   a  on the printed circuit board side, is consequently plugged into the associated contact openings  156 . They thus form an electrical press contact. 
     In the exemplary arrangement illustrated, the plug connector half  152  serves not only to supply current but also to connect the actuator assembly  10  to a bus system which is, for example, a CAN bus system. 
     Wheel speed sensors can moreover be connected to the actuator assembly  10  via the plug connector half  152 . 
     The electric motor  28  is also electrically connected to the printed circuit board  138 . 
     For this purpose, dimensionally stable contacts essentially parallel to the centre axis  34  protrude from the electric motor  28  and are referred to collectively as the second electrical line  162 . 
     Contact openings  164  on the printed circuit board  138  are likewise associated with the second electrical line  162 . 
     A passage  166  is moreover provided on the bulkhead wall  134 , through which the second electrical line  162  can come into engagement with the contact openings  164 . 
     The passage  166  is again equipped with a rim  168  such that it is ensured that the passage  166  is kept free of potting material  146 . 
     As already explained with regard to the first electrical line  154 , when the control assembly  12  is mounted, the second electrical line  162  also enters the associated contact openings  164  and forms an electrical press contact. 
     The locking actuator  112  is electrically connected to the printed circuit board  138  via a third electrical line  170  (see  FIGS.  1  and  2   ). 
     The third electrical line  170  is here also again formed from dimensionally stable contacts which protrude from the locking actuator  112  along the centre axes  34  and  50 . 
     Contact openings  172  in the printed circuit board  138  are again associated with the third electrical line  170  (see  FIG.  9   ). 
     So that the third electrical line  170  can be plugged into the contact openings  172 , a passage  174  is additionally provided on the bulkhead wall  134 . It is equipped with a rim  176  such that the passage  174  is also kept free of potting material  146 . 
     As already explained with regard to the first electrical line  154  and the second electrical line  162 , the third electrical line  170  is also pushed into the associated contact openings  172  and forms an electrical press contact when the control assembly  12  is mounted. 
     In summary, the printed circuit board  138  is therefore coupled electrically both to the plug connector half  152  and to the electric motor  28  and the locking actuator  112 . 
     On a side, facing the drive assembly  14 , of the bulkhead wall  134 , retaining ribs  178  are additionally provided in the region of the output gear wheel  40  and the gear wheel  44  which essentially form an envelope around a gear stage formed by the output gear wheel  40  and the gear wheel  44 . 
     Retaining ribs  180  are also provided in the region of the planetary gear stage  48 . 
     The retaining ribs  178 ,  180  here serve to ensure that a lubricating medium is held in the region of the gear wheels to be lubricated even when the output gear wheel  40 , the gear wheel  44  and the planetary gear wheel  48  rotate. 
     A function of a service brake can be provided by the actuator assembly  10  if the actuator assembly  10  is coupled to the brake calliper assembly  98 . The actuator assembly  10  is then operated in a service brake mode. The electric motor  28  is thus controlled by the control assembly  12  in such a way that it effects a desired shifting of the spindle nut  88 , i.e. of the actuating carriage  88 , along the centre axis  50  via the gear train  58 , the planetary gear stage  48  and the spindle drive  72 . 
     The electric motor  28  can here, in principle, be actuated in both directions of rotation such that the actuating carriage  88  can also be shifted actively in both directions. 
     It is likewise conceivable to use the electric motor  28  only to displace the actuating carriage  88  into an extended position, i.e. to apply the brake lining  96  to the brake rotor  100 . 
     The actuating carriage  88  can be restored to a retracted position and the pressure on the brake lining  96  can therefore be relaxed in this connection by virtue of elasticities which are inherent in the system, on the one hand, and the design of the actuator assembly  10  as not self-locking, on the other hand. 
     In such a service brake mode, the locking assembly  106  at all times assumes the release state (see  FIG.  8   ). 
     A function of a parking brake can moreover be provided by the actuator assembly  10 . 
     In this connection, a parking brake mode can be activated by the spindle nut  88  which forms the actuating carriage  88  being transferred into its extended position the electric motor  28  and the brake lining  96  thus being applied to the brake rotor  100 . The brake lining  102  is thus also applied to the brake rotor  100  by virtue of reaction forces acting inside the actuator assembly  10 . 
     The locking assembly  106  is then transferred into the locking state by the locking actuator  112  (see  FIG.  7   ). 
     Up to the point at which the ratchet  124  actually engages in the teeth of the output gear wheel  40  and rotation of the output shaft  38  is thus immobilized, the spindle nut  88  which forms the actuating carriage  88  is held actively in the extended position by the electric motor  28 , i.e. the electric motor  28  is correspondingly supplied with current. 
     The delivery of current to the electric motor  28  is interrupted only if the ratchet  124  engages securely in the locking contour formed by the teeth of the output gear wheel  40 . 
     There are several alternatives for deactivating the parking brake mode. 
     In one exemplary arrangement, to do this the electric motor  28  is actuated in a direction in which it stresses the spindle nut  88  which forms the actuating carriage  88  into the extended position, i.e. shifts it in the direction of the brake lining  96 . 
     In this way, the force on the locking lever  114  is relaxed. 
     The locking lever  114  can thus be easily transferred from the locking position into the release position by the locking actuator  112  (see  FIGS.  7  and  8   ). 
     Supply of current to the electric motor  28  can then be stopped such that the spindle nut  88  moves back automatically into the retracted position by virtue of the lack of any self-locking effect. 
     It is alternatively conceivable that the locking lever  114  is transferred into the release position not by actuation of the locking actuator  112  but by the electric motor  28  being actuated in a direction corresponding 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 associated with the retracted position of the spindle nut  88  such that the parking brake mode is deactivated. 
     It is of course also conceivable to deactivate the parking brake mode only 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. It may therefore not be necessary to shift the locking lever  114  under load. 
     The actuator assembly  10  can be produced as follows. 
     First, the housing base part  18  is supplied. 
     Then, the already premounted 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 are mounted the electric motor  28 , the spindle drive  72  and the gear unit  67  coupling the electric motor  28  and the spindle drive  72  drivingly and which comprises the gear 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 bulkhead wall  134  and the printed circuit board  138 . 
     The electric motor  28  is additionally connected electrically to the printed circuit board via the second electrical line  162  by the insertion of the control assembly  12  into the housing base part  18 . 
     The plug connector half  152  is moreover connected electrically the printed circuit board  138  via the first electrical line  154 . 
     The locking actuator  112  is also connected to the printed circuit board  138  via the third electrical line  170  when the control assembly  12  is inserted. 
     The electrical connections are here in each case created by the electrical lines  154 ,  162 ,  170  being plugged into the respective associated contact openings  156 ,  164 ,  172  to form a press contact. 
     Lastly, the housing base part  18  is closed by the housing cover  20  being placed on top.