Abstract:
A drive assembly having a motor accommodating bore for an electric motor, the bore being directed perpendicularly into an end face of a block-like accommodating body, and having a motor housing for accommodating a bearing provided for a motor shaft of the electric motor the bearing being fixed in an end-side motor housing section which extends into the motor accommodating bore. The invention provides for the electric motor to be frictionally fixed and centered in the motor accommodating bore by a motor holder that is fastened to the end-side motor housing section and projects into the motor accommodating bore.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is the U.S. National Phase Application of PCT International Application No. PCT/EP2014/050518, filed Jan. 14, 2014, which claims priority to German Patent Application No. 10 2013 200 545.8, filed Jan. 16, 2013, the contents of such applications being incorporated by reference herein. 
     FIELD OF THE INVENTION 
     The invention relates to a drive assembly, in particular for a slip-controlled brake system. 
     BACKGROUND OF THE INVENTION 
     A drive assembly of the abovementioned type is already known from DE 10 2009 048 109 A1 incorporated by reference herein. The drive assembly comprises a block-shaped mounting body, having a motor location hole for an electric motor, said hole being directed perpendicularly into an end face of the block-shaped mounting body, and having a motor housing for accommodating a bearing provided for a motor shaft of the electric motor, said bearing being fixed in an end-side motor housing section which extends as far as the motor accommodating hole. To secure the electric motor on the mounting body, the motor housing is provided with three tabs, which are secured on the mounting body by means of three holding screws while resting on the end of the mounting body. Owing to a large number of production steps which are required, this construction represents a relatively large expense and furthermore also does not allow a reduction in the protrusion of the motor housing on the mounting body 
     SUMMARY OF THE INVENTION 
     It is therefore an aim of an aspect the invention to develop a drive assembly of the type indicated in such a way that the abovementioned disadvantages are avoided. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further features and advantages of the invention are explained below by means of the description of two illustrative embodiments with reference to drawings. 
         FIG. 1  illustrates a drive assembly for a slip-controlled brake system according to a first embodiment. 
         FIG. 2  illustrates a drive assembly for slip-controlled brake system according to a second embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  shows a drive assembly used for slip-controlled motorcycle brake systems in longitudinal section, having a block-shaped mounting body  19 , into the end surface of which a motor location hole  4  for an electric motor  3  opens at right angles. The figure furthermore shows a motor housing  5  belonging to the electric motor  3 , said housing having a substantially hollow-cylindrical contour and accommodating a bearing  8  provided for a motor shaft  10  of the electric motor  3  in an end-side motor housing section  1 . Up to about half the length of the motor housing  5  is recessed into the motor location hole  4 , with the result that it protrudes by only a small amount above the end surface of the mounting body  19 , wherein the protrusion corresponds to the protrusion of a valve dome  20 , which is arranged next to the motor housing  5  and is part of an electromagnetically actuable pressure modulation valve. This equal-height arrangement has the advantage that, after a solenoid has been placed on the valve dome  20 , it is a particularly simple matter to bring the electrical contacts of the solenoid and the electrical contacts of the electric motor  3  directly into engagement with a circuit board, arranged horizontally above the electric motor  3  and the solenoid, of an electronic control unit, resulting in a compact overall construction since the control unit (not shown), as part of a covering cap, surrounds the upper side of the mounting body  19  in a fluidtight manner. As is readily apparent from the figure, the end-side motor housing section  1  extends by means of the adjoining circumferential surface of the motor housing  5  into the motor location hole  4  with a radial clearance, wherein a motor holder  2 , which is completely recessed into the motor location hole  4 , is advantageously secured on the end-side motor housing section  1 , the fixing and centering of the electric motor  3  within the motor location hole  4  thus being ensured by the motor holder  2 . 
     As a holding plate, the motor holder  2  is embodied in a particularly simple manner, wherein the holding plate has at its outer circumference a radial overlap  6  relative to the outside diameter of the motor housing  5 , said overlap being in engagement with the inner wall of the motor location hole  4  by means of a press fit, as shown in the figure. In a front view (not shown), the motor holder  2  is revealed to be an annular disk, which, as shown in the figure, has a collar  7  provided with a press fit both on its radial overlap  6 , for fixing in the motor location hole  4 , and on its inner circumference, for fixing on the end-side motor housing section  1 . The motor holder  2  in the form of an annular disk can be produced at particularly low cost by punching and deep drawing a thin sheet by means of a small number of processing steps. 
     In the illustrative embodiment under consideration, the collar  7  provided on the inner circumference of the motor holder  2  in the form of an annular disk is thus fixed by frictional engagement directly on a projection  9 , which surrounds the bearing  8  and forms part of the end-side motor housing section  1 . If desired or required, it is likewise possible for the collar  7  directly to surround the bearing  8  if the projection  9  is dispensed with or if the bearing  8  projects by a sufficient amount from the end-side motor housing section  1 . 
     As is furthermore apparent from  FIG. 1 , a further end-side motor housing section  12 , which accommodates the motor shaft  10  in a further bearing  11 , is provided on the opposite end of the electric motor  3  from motor housing section  1 . The further end-side motor housing section  12  is furthermore designed as a brush carrier plate to accommodate a plurality of brushes  14  in brush holders, with the result that the motor housing section  12  projecting from the motor location hole  4  forms a multifunctional unit. Adjoining the further bearing  11 , the motor shaft  10  carries a commutator  13  at a short axial distance from the bearing  11 , on which commutator the brushes  14  of the brush carrier plate rest under a spring pressure. 
     A fixing cap  15 , which is in engagement with the further motor housing section  12  and extends into the motor location hole  4  as far as the axial contact with a housing step  16 , is placed over the further end-side motor housing section  12 , which forms a unit with the tubular section of the motor housing  5 . The fixing cap  15  has an opening  17  in the region of the further end-side motor housing section  12 , in which opening the further bearing  11  is held with the end-side motor housing section  12  surrounding the further bearing  11 . 
     In the contact region of the housing step  16 , the fixing cap  15 , which surrounds at least half of the motor housing  5  in a bell shape, has a rim  18 , which is directed radially outward and is fixed positively and also nonpositively in the motor location hole  4  by means of plastic displacement, in the direction of the housing step  16 , of the material of the mounting body  19  adjoining the motor location hole  4 . 
     By means of the fixing cap  15  and of the holding plate  2 , reliable fastening of the electric motor  3  in the motor location hole  4  is thus ensured in order to actuate the pump piston of a radial piston pump  22 , said pump piston being guided transversely to the motor shaft  10  in a pump bore, by means of an eccentric  21  secured on the lower end of the motor shaft  10  in the illustrative embodiment under consideration. In this case, the holding plate  2 , which is adjacent to the eccentric, centers the electric motor  3  in the lower part of the motor location hole  4  and supports some of the motor torque, while the fixing cap  15 , which is introduced into the motor location hole  4  until it abuts the housing step  16  and locked, is used not only to absorb the remainder of the motor torque but also to define the desired installation depth of the electric motor  3 , for which purpose a sufficient axial clearance is provided between the holding plate  2  and the bottom of the motor location hole  4  to compensate installation tolerances. 
     To facilitate assembly, the motor location hole  4  has a hole section  23  which, as compared with the press-fit region, situated in the lower end section of the motor location hole  4  of the holding plate  2 , is widened slightly relative to the outside diameter of the holding plate  2  between its housing step  16  and said press-fit region in order to avoid having to press the electric motor  3  into the mounting body  19  with a large expenditure of force over the entire depth of the motor location hole  4 . 
     The drive assembly depicted in  FIG. 2  differs from the drive assembly shown in  FIG. 1  in that the motor housing section  12  is accommodated with a radial clearance within the opening  17  provided in the fixing cap  15 , with the result that there is advantageously no transmission of force to the motor housing section  12  while the fixing cap  15  is being placed on. Deformation of the motor housing during the mounting of the fixing cap  15  is thereby excluded. An interspace  25  is provided between the inner wall of the fixing cap  15  and the outer wall of the further motor housing section  12 , said interspace extending along the motor housing  5  into the hole section  23  of the mounting body  19 . According to  FIG. 2 , an elastically deformable ring element  24 , in which the motor housing  5  is mounted in a more or less elastic way in the fixing cap  15 , is clamped into the interspace  25 . Elastic support for the motor housing  4  in the fixing cap  15  with vibration- and hence noise-absorbing properties is thus obtained at a location remote from the fixing of the electric motor  3  in the motor holder  2 . 
     All further details which are apparent from  FIG. 2  but have not hitherto been described explicitly with reference to  FIG. 2  can be found in the description of the drive assembly depicted in  FIG. 1 . 
     LIST OF REFERENCE SIGNS 
     
         
           1  motor housing section 
           2  motor holder 
           3  electric motor 
           4  motor location hole 
           5  motor housing 
           6  overlap 
           7  collar 
           8  bearing 
           9  projection 
           10  motor shaft 
           11  bearing 
           12  motor housing section 
           13  commutator 
           14  brush 
           15  fixing cap 
           19  housing step 
           17  opening 
           18  rim 
           19  mounting body 
           20  valve dome 
           21  eccentric 
           22  radial piston pump 
           23  hole section 
           24  ring element 
           25  interspace