Patent Publication Number: US-2023151865-A1

Title: Actuator assembly

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to German Priority Application No. 102021129958.6, 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, in particular for an electromechanical vehicle brake, having a drive assembly and a linearly guided actuating slide for a brake pad, which can be moved optionally between a retracted position and an extended position via the drive assembly. 
     BACKGROUND 
     The existing components of the drive assembly and of the actuating slide must be aligned sufficiently accurately relative to one another to ensure reliable functioning of the vehicle brake. 
     Furthermore, the axial and transverse forces and torques occurring during operation of the vehicle brake must be reliably supported. 
     Moreover, the confined space conditions in the vehicle represent a challenge. 
     SUMMARY 
     The present disclosure specifies an actuator assembly which, while being of compact design, makes possible in a simple manner the most accurate possible alignment of the existing components with respect to one another and which is sufficiently stable to withstand the forces which occur. 
     According to the disclosure an actuator assembly for a vehicle brake is disclosed, in particular an electromechanical vehicle brake, having a brake caliper in which there is an intermediate space for accommodating a brake rotor, a drive housing, in which a drive assembly of the actuator assembly is accommodated, wherein the drive housing is fixedly connected to the brake caliper, a linearly guided actuating slide for a brake pad, which can be moved optionally between a retracted position and an extended position via the drive assembly, and a frame part having an accommodation space, in which a transmission unit of the drive assembly is at least partially accommodated, wherein an electric motor is secured on the frame part, which electric motor is coupled in terms of drive to the actuating slide via the transmission unit and a spindle drive. The frame part is secured on the drive housing. 
     For example, the frame part is screwed to the drive housing. 
     Since the frame part is secured on the drive housing, which is in turn fixedly connected to the brake caliper, forces which occur during operation can be transmitted from the frame part, via the drive housing, to the brake caliper. In this way, a particularly high stability of the actuator assembly is ensured. 
     The frame part is furthermore suitable for securing and aligning various components, such as the electric motor, and thus contributes to simple assembly. In particular, inter alia, the electric motor can be pre-mounted on the frame part before the frame part is secured on the drive housing. 
     A bearing journal can be secured on the frame part, on which journal a gear wheel is mounted which meshes with an output gear wheel, which is arranged on an output shaft of the electric motor. The gear wheel can thus be mounted in a defined position on the frame part, on which the electric motor is also secured, with the result that the gear wheel and the output shaft of the electric motor are aligned relative to one another in a defined position by way of the frame part. This also contributes to a simplification of assembly. 
     A ring gear of a planetary transmission stage can extend along an inner circumference of the accommodation space. In other words the accommodation space can serve as a positioning aid for aligning the ring gear. Consequently, separate positioning aids are not required. Moreover, the ring gear is supported on the frame part during operation of the actuator assembly. 
     The gear wheel which meshes with the output gear wheel is coupled, for example, to a sun wheel of the planetary transmission stage, for example via a further gear wheel, which is coupled to a sun wheel of the planetary transmission stage. As a result, a gear transmission is formed which couples the electric motor to the planetary transmission stage, As a result, the electric motor can be arranged parallel to a centre line of the planetary transmission stage and to the actuating slide, contributing to a compact design of the actuator assembly. A length of the actuator assembly can be reduced by such an arrangement. 
     The actuating slide is guided linearly, in a bearing sleeve for example, wherein a guide for aligning the bearing sleeve is formed on the frame part. The bearing sleeve can thus be positioned accurately in a simple manner relative to the frame part and consequently also relative to the brake caliper. A movement path of the actuating slide is thus also precisely defined. 
     The guide is formed, for example, by an annular section, into which an extension of the bearing sleeve is inserted. An outer wall of the bearing sleeve is thus supported on an inner wall of the bearing sleeve. 
     The brake caliper can be in two parts such that the intermediate space for accommodating the brake rotor is formed in a first caliper part, and the bearing sleeve is accommodated in the second caliper part. Manufacturing the brake caliper in two parts makes it a simpler matter to remove the individual caliper parts from the mould. Moreover, mounting of the guide sleeve in the brake caliper is simplified. 
     The guide sleeve is pressed into the second caliper part, for example. 
     The second caliper part forms, in particular, a bridge between the drive housing and the first caliper part. 
     The guide can be arranged concentrically with respect to the accommodation space and the frame part can taper in a funnel shape from the accommodation space to the guide. As a result of the taper, a diameter of the bearing sleeve can be selected independently of a diameter of the ring gear arranged in the accommodation space. As a result of the concentric arrangement of the accommodation space and the guide, a centre line of the planetary transmission stage coincides with a centre line of the actuating slide. 
     For example, a reinforcing part is provided which spans the accommodation space at the end, wherein the reinforcing part is secured on the frame part and/or on the drive housing. The reinforcing part ensures additional stabilization and stiffening of the drive housing, in particular in the region in which the planetary transmission stage is mounted. 
     The drive housing can be sleeve-shaped and dosed by a housing cover, wherein a control assembly is accommodated in the housing cover. This likewise contributes to a compact construction of the actuator assembly. 
     The drive housing can be screwed to the brake caliper in different positions, wherein the positions differ in the angular position of the drive housing relative to the brake caliper. In this way, the advantage is achieved that adaptation of the actuator assembly to different installation space situations is possible. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       Further advantages and features according to the disclosure will be found in the following description and in the accompanying drawings, to which reference is made. In the drawings: 
         FIG.  1    shows an actuator assembly according to the disclosure, 
         FIG.  2    shows the actuator assembly according to the disclosure from  FIG.  1    in a sectional illustration, and 
         FIG.  3    shows the actuator assembly according to the disclosure from  FIG.  1    in a further sectional illustration. 
     
    
    
     DETAILED DESCRIPTION 
       FIG.  1    shows an actuator assembly  10  as part of an electromechanical vehicle brake. 
     The actuator assembly  10  comprises a drive assembly  12  that can be assembled as a separate subunit. 
     Furthermore, the actuator assembly  10  comprises a control assembly  14  (see  FIG.  2   ) that can be assembled as a separate subunit. 
     The drive assembly  12  is arranged in a drive housing  16 . 
     The drive housing  16  is substantially sleeve-shaped and is closed on one side by a housing cover  18  (see  FIG.  2   ). 
     In the illustration, the housing cover  18  is shell-shaped. 
     The control assembly  14  is accommodated in the housing cover  18 . For example, the control assembly  14  is pre-mounted in the housing cover  18  before the housing cover  18  is placed on the drive housing  16 . 
     The drive housing  16  can be a casting, which is produced from metal or plastic. 
     The housing cover  18  can be made of plastic. 
     Furthermore, the actuator assembly  10  comprises a brake caliper  15 , in which an intermediate space  17  for a brake rotor  19 , i.e. a brake disc, is formed. 
     With its end close to the brake rotor  19 , the drive housing  16  is partially pushed onto the brake caliper  15  and fixedly connected, in particular screwed, to the brake caliper  15 . 
     The drive housing  16  can be screwed to the brake caliper  15  in different positions, specifically in two different positions. This can be seen in  FIG.  1    via the additional hole  20 . The positions differ in the angular position of the drive housing  16  relative to the brake caliper  15 . 
     The drive assembly  12  comprises a carrier assembly  22 , which has a frame part  24 . 
     The frame part  24  is, for example, plate-shaped. 
     For example, the frame part  24  is a casting. 
     A first fastening interface  26 , at which an electric motor  28  is secured, is provided on the plate-shaped frame part  24 . The electric motor  28  can be pre-mounted, in particular on the frame part  24 . 
     More precisely, the electric motor  28  is connected to the frame part  24  in a captive manner via the first fastening interface  26 . For this purpose, holes  30  are provided in the frame part  24 , by way of which the electric motor  28  is secured on the frame part  24  via a screw. Three holes  30  are provided, for example. The frame part  24  absorbs the forces of the electric motor  28  and holds it. 
     Moreover, a centring device  32  in the form of a cylindrical aperture is arranged in the frame part  24 . The electric motor  28  can thus be secured on the frame part  24  in a centred manner with respect to a centre line  34  of the first fastening interface  26 . 
     In addition, an anti-rotation device  36  in the form of an aperture is provided in the frame part  24 , said aperture being designed to prevent the electric motor  28  from rotating with respect to the frame part  24 , in particular via an additional retention pin  37 . 
     An output gear wheel  40  is arranged on an output shaft  38  of the electric motor  28  in order to introduce torque into the drive assembly  12 . 
     In addition, a bearing journal  42  is secured on the frame part  24  and a gear wheel  44  is mounted on the said bearing journal and meshes with the output gear wheel  40 . 
     Moreover, an accommodation space  46  for a planetary transmission stage  48  is provided on the frame part  24 . 
     The accommodation space  46  is cylindrical. 
     A centre line  50  of the accommodation space  46  is arranged substantially parallel to the centre line  34  of the first fastening interface  26 . 
     Furthermore, a reinforcing part  52  is secured on the frame part  24  in such a way that it spans the accommodation space  46  axially at the end with respect to the centre line  50 . 
     The reinforcing part  52  is secured on, in particular screwed to, the frame part  24  and/or the drive housing  16 . 
     As an alternative or in addition, at least some screws for securing the reinforcing part  52  can project through the frame part  24  and be screwed into the drive housing  16 . 
     As illustrated, the reinforcing part  52  is substantially cruciform. 
     Moreover, a bearing location  54  for a gear wheel  56  arranged coaxially with the planetary transmission stage  48  is provided on the reinforcing part  52 . 
     Gear wheel  56  meshes with gear wheel  44 . 
     Consequently, a gear transmission  58  is formed by gear wheel  44  and gear wheel  56 , the output gear wheel  40  acting as the input member of the said gear transmission. 
     Furthermore, gear wheel  56  is coupled to a sun wheel  60  of the planetary transmission stage  48  (see  FIGS.  2  and  3   ). In this way, the gear transmission  58  and the planetary transmission stage  48  are coupled in terms of drive. Specifically, gear wheel  44  is coupled to the sun wheel  60  of the planetary transmission stage  48  via gear wheel  56 . 
     It is optionally also possible for gear wheel  56  to be formed in one piece with the sun wheel  60  of the planetary transmission stage  48 . 
     The planetary transmission stage  48  furthermore comprises a ring gear  62 , which extends along an inner circumference of the accommodation space  46 . 
     As illustrated, a total of three planet wheels  64  is provided between the sun wheel  60  and the ring gear  62  in terms of drive. These are mounted rotatably on a planet carrier  66  (see  FIGS.  2  and  3   ). 
     In this case, the planet carrier  66  represents an output element of the planetary transmission stage  48 . 
     The gear transmission  58  and the planetary transmission stage  48  are also referred to jointly as a transmission unit  67 . 
     The transmission unit  67  is partially accommodated in the accommodation space  46 . More precisely, the planetary transmission stage  48  is partially accommodated in the accommodation space  46 . 
     The frame part  24  thus serves for pre-mounting and alignment of various components. 
     In particular, the components secured on the frame part  24  can be mounted on the drive housing  16  by securing the frame part  24  in a defined position on the drive housing  16 , as shown in  FIG.  1   . 
     Moreover, the frame part  24  has a guide  68  for aligning a bearing sleeve  70 . 
     In this case, a centre line of the guide  68  coincides with the centre line  50  of the accommodation space  46  and, for this reason, is provided with the same reference sign. 
     The frame part  24  tapers in a funnel shape from the accommodation space  46  towards the guide  68 . 
     The guide  68  is arranged concentrically with respect to the accommodation space  46 . 
     The bearing sleeve  70  is accommodated in the brake caliper  15 . 
     The brake caliper  15  is in two parts and has a first caliper part  74 , in which the intermediate space  17  for accommodating the brake rotor  19  is formed, and a second caliper part  76 , in which the bearing sleeve  70  is accommodated. 
     The two caliper parts  74 ,  76  are screwed together. 
     For example, the bearing sleeve  70  is pressed into the second caliper part  76  or welded thereto. 
     A spindle drive  72  is accommodated in the bearing sleeve  70 . 
     This comprises a spindle  84 , which in the present case is designed as a recirculating ball screw (see  FIGS.  2  and  3   ). 
     In this case, the spindle  84  is connected for conjoint rotation to the planet carrier  66  via a toothed section  86 . 
     Thus, the spindle drive  72  can be driven via the electric motor  28 . In detail, the electric motor  28  is coupled in terms of drive to the spindle drive  72  via the gear transmission  58  and the planetary transmission stage  48 . 
     An actuating slide  88  is mounted on the spindle  84  and is designed, in particular, as a spindle nut of piston-shaped configuration. 
     Here, rotation of the spindle  84  causes an axial movement of the actuating slide  88  along the centre line  50 . 
     In this case, the actuating slide  88  is guided along the centre line  50  in the bearing sleeve  70 , more precisely on a running surface  90 , which is formed on an inner side of the bearing sleeve  70 . The running surface  90  corresponds substantially to a cylinder lateral surface forming the inner circumference of the bearing sleeve  70 . 
     Furthermore, the actuating slide  88  is prevented from performing a relative rotation about the centre line  50  via an anti-rotation device  92 , which is designed as at least one oblong hole in the bearing sleeve  70 . For this purpose, at least one anti-rotation element  94  is attached to the actuating slide  88  and engages in each case in an oblong hole (see  FIG.  1   ). The anti-rotation element  94  is a radial extension. 
     The bearing sleeve  70  is open towards the intermediate space  17 , and therefore the actuating slide  88  can be moved into the intermediate space  17 . 
     The actuating slide  88  is used to apply a first brake pad  96  of a brake caliper assembly  98  to the brake rotor  19 . That is to say that the first brake pad  96  can be actively moved via the actuator assembly  10  towards a brake rotor  19 , which is designed as a brake disc. 
     In detail, the actuating slide  88  is optionally transferred via the electric motor  28 , via the gear transmission  58 , the planetary transmission stage  48  and the spindle drive  72 , into an extended position associated with the application of the first brake pad  96  to the brake rotor  19 . 
     As a result of the reaction forces acting within the actuator assembly  10  and the brake caliper assembly  98 , a second brake pad  102  is thereby also applied to the brake rotor  19 . 
     It is self-evident that, by operating the electric motor  28 , the actuating slide  88  can be moved in the same way into a retracted position, which is associated with lifting the first brake pad  96  and the second brake pad  102  from the brake rotor  19 . 
     In the present case, the actuator assembly  10  is designed to be free of self-locking, with the result that, owing to inherent elasticities in the system, the actuating slide  88  also moves back automatically into the retracted position when it is no longer actively being pushed into the extended position via the electric motor  28 .