Patent Publication Number: US-2022227422-A1

Title: Unit mounting in a vehicle

Description:
The invention relates to a unit mounting in a vehicle according to the preamble of claim  1 . 
     The drive unit of a vehicle, such as an internal combustion engine or an electric machine, is typically mounted in a motor compartment of the vehicle via vibration-damping unit bearings on a support structure, such as an axle support or auxiliary frame, of the vehicle body, for example, in a three-point or four-point mounting. 
     In a generic unit mounting, the drive unit is attached via a unit bearing to a body-side bearing bracket. The unit bearing is implemented as a rubber-metal bearing having a sleeve-shaped bearing core, which is screwed onto the body-side bearing bracket by means of a bearing bolt guided through the sleeve-shaped bearing core. The unit housing has a bearing receptacle into which the unit bearing is inserted (in particular pressed in). 
     In the prior art, the housing-fixed bearing receptacle can be implemented as a bearing eye open on both sides in the axial direction, which has a hollow cylindrical receptacle space into which the unit bearing is pressed. The attachment of the housing-fixed unit bearing to the bearing bracket can be implemented as follows: The bearing bracket can thus have two bracket wings which are positioned axially on both sides of the sleeve-shaped bearing core of the unit bearing. The two bracket wings and the interposed bearing core are screwed together to form an axial press group with the aid of a bearing bolt. The bearing bolt extends with its bolt shaft through the sleeve-shaped bearing core, wherein the two bracket wings and the sleeve-shaped bearing core are clamped in the axial direction between a bolt head of the bearing bolt and a screw nut, which is screwed together with the bolt shaft. 
     In the above prior art, the attachment of the unit bearing to the bearing bracket is linked to both installation space expenditure and component expenditure. Moreover, tool access to the unit bearing is required on both sides in the axial direction to enable installation or removal of the drive unit. 
     An auxiliary frame for a motor vehicle is known from DE 10 2013 007 976 A1. A subframe for a motor vehicle is known from DE 199 09 945 C1. An arrangement of an electric motor unit in the motor compartment of a motor vehicle is known from DE 10 2012 012 327 A1. 
     The object of the invention is to provide a unit mounting for a drive unit, in which the unit mounting is implementable with a greater number of degrees of freedom in comparison to the prior art with reduced installation space expenditure and/or with reduced component requirement in comparison to the prior art. 
     The object is achieved by the features of claim  1 . Preferred refinements of the invention are disclosed in the dependent claims. 
     According to the characterizing part of claim  1 , the housing-side bearing receptacle is not implemented as a bearing eye open on both sides axially but rather as a bearing cup open on one side, specifically with a closed bearing base from which a cylindrical peripheral circumferential wall is raised. The housing-fixed bearing receptacle formed as a bearing cup provides only a one-sided installation access for inserting, in particular pressing in the unit bearing. 
     In a first technical implementation, the attachment of the unit bearing to the bearing bracket can be implemented as follows: The sleeve-shaped bearing core of the unit bearing can thus have an internal thread with which the bearing bolt is screwed together. In this case, a screw nut can be omitted to implement the screw connection to the unit bearing. The bearing bolt can have a bolt shaft, which can be brought into threaded engagement with the internal thread of the bearing core, and a bolt head. The bolt shaft can be guided with hole clearance through a screw hole of the bearing bracket, while the bolt head is supportable on an opening edge region of the bearing bracket screw hole facing away from the unit bearing. In this case, the bearing bracket can be clamped with its opening edge region between the bolt head and an end face (facing toward the bearing bracket) of the sleeve-shaped bearing core. 
     With regard to a screwing/unscrewing process of the bearing bolt that can be carried out properly, it is preferred if a rotation lock is assigned to the sleeve-shaped bearing core. With the aid of the rotation lock, the sleeve-shaped bearing core can be held in a rotationally fixed manner during the screwing/unscrewing of the bearing bolt. The rotation lock can be formed, for example, between the bearing core and the bearing bracket or alternatively between the bearing core and the unit housing, in particular as interlocking formfitting contours. 
     For a simple installation/removal of the drive unit into or out of the vehicle motor compartment, it is preferred if the bearing bracket is embodied in at least two parts. For example, the bearing bracket can have a body-fixed main body and an adapter part. The adapter part can be removably installed on the main body, in particular in a screw connection. It is preferred if both the bearing bracket screw hole, through which the bolt shaft is guided, and also the bearing bracket opening edge, on which the bolt head of the bearing bolt is supportable, are formed on the adapter part. In contrast thereto, neither the bearing bracket screw hole nor the bearing bracket opening edge region can be formed on the main body. 
     The main body can be manufactured in this case from a massive solid material which can be designed without a screw hole for the bearing bolt. Instead of this, only smaller-diameter screw holes are provided in the main body to screw the adapter part onto the main body. 
     The adapter part can be brought into contact with the main body of the bearing bracket at a joining plane. For example, the joining plane can extend as a vertical plane in the vehicle vertical direction. In this case, the joining plane can be oriented perpendicularly to the screw axis of the bearing bolt, which is oriented, for example, in the vehicle longitudinal direction and/or in the vehicle transverse direction. The adapter part can be screwed onto the main body using one or more screw connections. The screw axes thereof can preferably (with regard to a stable attachment) be oriented axially parallel or perpendicularly to the bearing bolt screw axis. 
     In one specific embodiment, the adapter part can be a shell-shaped profile part, specifically having the opening edge region as the profile base, from which a circumferential profile wall is raised, which merges radially outward into a ring flange. In this case, the adapter part can be screwed using its ring flange onto the main body, specifically while forming a bolt head installation space between the profile base of the adapter part and the joining plane. The ring flange of the adapter part can be attached with the aid of screw connections on the bearing bracket main body, the screw axes of which extend axially parallel to the bearing bolt screw axis and are arranged circumferentially distributed around this bearing bolt screw axis. 
     In a second technical implementation of the invention, the bolt head of the bearing bolt can no longer be positioned outside the bearing cup, but instead of this can be positioned inside the housing-fixed bearing cup, specifically in an installation space between the bearing base of the housing-side bearing cup and an end face of the sleeve-shaped bearing core facing toward the bearing base. In this case, the bolt shaft adjoining the bolt head can be guided with hole clearance through the sleeve-shaped bearing core, wherein the bearing core does not have to have an internal thread. The bearing bolt guided with hole clearance through the sleeve-shaped bearing core can be brought into thread engagement with an internally threaded drilled hole of the bearing bracket using its bolt tip protruding beyond the bearing core. In this way, an axial press group results, in which the bearing core is clamped between the bolt head and an opening edge region of the internally threaded drilled hole of the bearing bracket. 
     To ensure simple installation/removal of the drive unit into or out of the vehicle motor compartment, it is preferred if the above bearing bracket is constructed in a total of three parts, specifically the main body, the adapter part, and an additional clamping part, the function of which is described later. The adapter part can be attached to the main body (in particular in a screw connection) in a joining plane parallel to the bearing bolt screw axis. The joining plane can extend in this case in a horizontal plane which is spanned between the vehicle longitudinal direction and the vehicle transverse direction. The adapter part can be clamped with the aid of the screw connections between the body-fixed main body and the clamping part. For easy tool access, it is preferred if the screw axes of the screw connections are oriented perpendicularly to the bearing bolt screw axis. 
     Two exemplary embodiments are described hereinafter on the basis of the appended drawings. 
    
    
     
       In the figures: 
         FIG. 1  shows a unit mounting according to a first exemplary embodiment; 
         FIGS. 2 and 3  each show views which illustrate an assembly process of the unit mounting; 
         FIGS. 4 to 7  each show views corresponding to  FIGS. 1 to 3  according to a second exemplary embodiment. 
     
    
    
     A unit mounting is shown in  FIG. 1 , in which a drive unit is installed using its unit housing  1  via a unit bearing  3  designed as a rubber-metal bearing on a body-side bearing bracket  5 . The bearing bracket  5  is fastened in  FIG. 1  on an indicated auxiliary frame  7 . The auxiliary frame  7  is in turn attached to the vehicle body (not shown) of the vehicle. The unit bearing  3  has a housing-fixed radially outer bearing sleeve  9  and a radially inner sleeve-shaped bearing core  11  as the body-side bearing component. An elastomer body  13  is vulcanized in between the radially inner bearing core  11  and the radially outer bearing sleeve. In  FIG. 1 , the outer bearing sleeve  9  of the unit bearing  3  is pressed into a bearing cap  15 , which is formed from the same material and in one piece on the unit housing  1 . The bearing cup  15 , which is formed rotationally symmetrical around a bearing axis L, has a hollow cylindrical receptacle space  17  ( FIG. 2 ), which is delimited by a closed bearing base  19  and by a cylindrically circumferential peripheral wall  21  raised therefrom. 
     In  FIG. 1 , the bearing bracket  5  is embodied in two parts, specifically having a main body  23  attached to the auxiliary frame  7  and an adapter part  25 . The attachment of the bearing bracket  5  on the unit bearing  3  is implemented according to  FIG. 1  with the aid of a bearing bolt  27 , which screws the bearing bracket  5  onto the unit bearing  3 . For this purpose, the bearing bolt  27  is in thread engagement with an internal thread  29  of the sleeve-shaped bearing core  11 . 
     In  FIG. 1 , the bearing bolt  27  has a shaft  31  in thread engagement with the internal thread  29  of the bearing core  11  and a bolt head  33 . The bolt shaft  31  is guided in  FIG. 1  with hole clearance through a screw hole  35  ( FIG. 2 ) of the adapter part  25 , while the bolt head  33  is supported on an opening edge region  37  of the screw hole  35  of the adapter part  25  facing away from the unit bearing  3 . The bearing bracket  5  is therefore supported with its opening edge region  37  between the bolt head  33  and an end face  39  of the sleeve-shaped bearing core  11 . 
     As can furthermore be seen from  FIG. 1 , the adapter part  35  is a shell-shaped profile part, specifically having the opening edge region  37  as the profile base, from which a circumferential profile wall  41  is raised. The circumferential profile wall  41  merges radially outward into a ring flange  43 , which in  FIG. 1  is in contact with the main body  23  in a vertical joining plane F. In  FIG. 1 , the joining plane F is positioned perpendicularly to the bearing axis L. The adapter part  25  is screwed onto the main body  23  using its ring flange  43  via screw connections S. The screw axes of these screw connections S are oriented axially parallel to the bearing bolt screw axis L in  FIG. 1 . Moreover, the screw connections S are positioned circumferentially distributed on the ring flange  43  of the adapter part  25 . In  FIG. 1 , an installation space  45 , in which the bolt head  33  is positioned, is provided between the joining face F and the profile base (that is to say the opening edge region  37 ) of the adapter part  25 . 
     An assembly process of the unit mounting shown in  FIG. 1  is described hereinafter on the basis of  FIGS. 2 and 3 : Firstly, the unit mounting  3  is pressed into the bearing cup  5  of the unit housing  1  ( FIG. 2 ). Subsequently, the adapter part  25  is clamped on the unit bearing  3  by screwing the bearing bolt  27  into the internal thread  29  of the sleeve-shaped bearing core  11  ( FIG. 3 ). After the pressing in process, the drive unit is positioned with respect to the bearing bracket main body  23  so that the adapter part  25  can be screwed onto the bearing bracket main body  23 . 
     A second exemplary embodiment is shown in  FIG. 4 , in which the bolt head  33  of the bearing bolt  27  is no longer positioned outside the housing-fixed bearing cup  15 , but rather is arranged in an installation space  47  between the bearing base  19  and an end face of the sleeve-shaped bearing core  11  facing toward the bearing base. The bolt shaft  31  is guided with hole clearance through the sleeve-shaped bearing core  11  in  FIG. 4 . In contrast to the first exemplary embodiment, in  FIG. 4 , the sleeve-shaped bearing core  11  is not embodied having an internal thread  29 . 
     As can furthermore be seen from  FIG. 4 , the bearing bolt  27  is brought into thread engagement with an internally threaded drilled hole  51  of an adapter part  25  of the bearing bracket  5  using its bolt tip protruding beyond the sleeve-shaped bearing core  11 . An axial press group thus results, in which the sleeve-shaped bearing core  11  is clamped between the bolt head  33  and an opening edge region  53  of the internally threaded drilled hole  51  of the adapter part  25  of the bearing bracket  11 . 
     In  FIG. 4 , the bearing bracket  11  is constructed in a total of three parts, specifically having the main body  23 , the adapter part  25 , and an additional clamping part  55 , which are all connected to one another via horizontal joining planes F. The adapter part  25  is thus attached to the main body  23  (with the aid of screw connections S) in  FIG. 4  in a joining plane F parallel to the bearing bolt screw axis L. As mentioned above, the respective joining plane F is a horizontal plane which is spanned between a vehicle longitudinal direction x and a vehicle transverse direction y. The adapter part  25  is clamped in  FIG. 4  with the aid of screw connections S between the main body  23  and the clamping part  55 . The screw axes of the screw connections S are oriented perpendicularly to the bearing bolt screw axis L in  FIG. 4 . 
     An assembly process of the unit mounting shown in  FIG. 4  is described hereinafter on the basis of  FIGS. 5 to 7 : Accordingly, firstly the bearing bolt  27  is guided loosely through the unit bearing  3  ( FIG. 5 ). Subsequently, the unit bearing  3  is pressed into the hollow cylindrical receptacle space  17  of the housing-side bearing cup  15  ( FIG. 5 ). In a following process step, the adapter part  25  (separately from the main body  23  and the clamping part  55  of the bearing bracket  5 ) is screwed together with the bolt tip of the bearing bolt  27  protruding beyond the unit bearing  3  ( FIG. 6 ). The axial press group shown in  FIG. 6  thus results, in which the sleeve-shaped bearing core  11  is clamped between the bolt head  33  and the opening edge region  53  ( FIG. 6 ) of the internally threaded drilled hole  51  of the adapter part  25 . In a further process step, the adapter part  25  is clamped between the main body  23  of the bearing bracket  5  and the clamping part  55  with the aid of the screw connections S ( FIG. 4 ). 
     LIST OF REFERENCE SIGNS 
     
         
           1  unit housing 
           3  unit bearing 
           5  bearing bracket 
           7  auxiliary frame 
           9  outer sleeve 
           11  bearing core 
           13  elastomer body 
           15  bearing cup 
           17  hollow cylindrical receptacle space 
           19  bearing base 
           21  circumferential wall 
           23  main body 
           25  adapter part 
           27  bearing bolt 
           29  internal thread 
           31  bolt shaft 
           33  bolt head 
           35  screw hole 
           37  opening edge region 
           39  end face of the bearing core 
           41  profile wall 
           43  ring flange 
           45  installation space 
           47  installation space 
           49  end face of the bearing core 
           51  internally threaded drilled hole 
           53  opening edge region 
           55  clamping part 
         F joining plane 
         S screw connections