Patent Publication Number: US-2022231584-A1

Title: Method and apparatus for manufacturing a housing

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of international patent application PCT/EP2020/074921, filed on 7 Sep. 2020 designating the U.S., which international patent application claims priority from German patent application No. 10 2019 127 797.3 filed on 15 Oct. 2019. The entire contents of these priority applications are incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The invention relates to a method and an apparatus for manufacturing a housing having a sleeve-shaped housing wall extending about a longitudinal axis of the housing and a cover arranged inside the housing wall transverse to the longitudinal axis at a predetermined position between longitudinal ends of the housing wall. 
     BACKGROUND 
     A housing of the type mentioned above can, for example, be a housing for an electric motor. The cover may have a bearing flange for the motor shaft. The cover is located inside the housing wall, i.e. in the cavity formed by the housing wall at a position spaced from both longitudinal ends of the housing wall. The cover divides the interior of the housing into a first subspace, which serves to accommodate the stator of the electric motor, and the other subspace can accommodate, for example, the control electronics for the motor. 
     Such a complex housing cannot be manufactured in one piece from a blank using conventional forming processes such as deep drawing because of the cover located in the cavity of the housing. It is conceivable to manufacture such a housing in one piece or monolithically using a die casting process. However, a housing produced by die casting has the disadvantage of high cost. 
     A concept is also conceivable in which such a complex housing is manufactured from individual parts, each made from a blank in a forming process, which are assembled together after their individual manufacture. For example, the sleeve-shaped housing wall and the cover could be manufactured separately from one blank each in a deep-drawing process, and the cover could then be inserted into the predetermined position within the housing wall. However, the production of individual parts with one tool each on corresponding separate apparatuses is also disadvantageous in terms of manufacturing costs. 
     SUMMARY 
     An object of the invention is to provide a method of manufacturing a housing of the type mentioned at the beginning, with which such a housing can be manufactured with low manufacturing costs. 
     A further object of the invention is to provide an apparatus for manufacturing such a housing. 
     According to the present disclosure, a method of manufacturing a housing is provided, the housing to be manufactured having a sleeve-shaped housing wall extending about a longitudinal axis of the housing and a cover disposed inside the housing wall transverse to the longitudinal axis at a predetermined position between longitudinal ends of the housing wall, the method comprising:
         providing a precursor of the housing, in which the cover is formed integrally with the housing wall and is disposed at one of the longitudinal ends of the housing wall,   separating the cover from the housing wall,   displacing the cover relative to the housing wall in the direction of the longitudinal axis from one longitudinal end into the predetermined position.       

     The method according to the invention thus departs from the concept of manufacturing a complex housing by first manufacturing individual parts of the housing separately and then assembling them. Instead, a precursor of the housing is first provided, in which the cover is formed in one piece, i.e. monolithically, with the housing wall and is arranged at one of the longitudinal ends of the housing wall. 
     The monolithic precursor of the housing can advantageously be produced by conventional forming processes from a single blank in a forming device. In the precursor of the housing, the cover is already in the correct position in the direction transverse to the longitudinal axis, so that in contrast to separate production of the cover and housing wall, a positioning process in this respect is advantageously not required. However, the cover is not yet at the axial predetermined position between the longitudinal ends within the housing wall. Therefore, the method according to the invention further provides for separating the cover from the housing wall after manufacturing the precursor of the housing and for displacing it relative to the housing wall along the longitudinal axis of the housing wall from the one longitudinal end at which the cover is located in the precursor of the housing into the predetermined position (desired position) and thus positioning it. After displacement to the desired position, the cover can be joined to the housing wall in the desired position. 
     The process according to the invention is characterized by the fact that the separation and positioning (displacing) of the cover and, if necessary, the production of the precursor of the housing and, if necessary, the joining can be carried out in a single production line. In this case, the production of the precursor, the separating and positioning of the cover and, if necessary, the joining can be carried out in a press cycle. The same production line can also include a joining station. 
     According to the present disclosure, an apparatus for carrying out the method according to the present disclosure comprises:
         a separating device for separating the cover from the housing wall, and   a positioning device for displacing the cover relative to the housing wall along the longitudinal axis into the predetermined position.       

     Preferably, the apparatus comprises a manufacturing device for manufacturing the precursor of the housing. Furthermore, the device preferably comprises a joining device for joining the cover to the housing wall in the predetermined position. 
     Preferably, the production of the precursor of the housing and the separation and displacement of the cover are carried out in different working stations of the same production line. For this purpose, the apparatus according to the invention preferably has a manufacturing device for manufacturing the precursor of the housing. 
     The time and cost of manufacturing the housing is thus further reduced. 
     In the method according to the invention, providing the precursor of the housing preferably comprises a one-piece, i.e. monolithic, forming of the housing wall and the cover from a same blank. 
     All conventional forming processes, such as deep drawing, reverse drawing, necking, which are carried out in one or more forming stages, can be used as forming processes. 
     For this purpose, the apparatus according to the invention may comprise a forming device for jointly forming the cover and the housing wall in one piece from a same blank in one or more forming stages. 
     In another preferred embodiment of the method, providing the precursor of the housing comprises forming the cover with a skirt extending in longitudinal direction of the housing wall along a partial length of the housing wall and circumferentially about the longitudinal axis. 
     The advantage of this measure is that the skirt provides a flat abutment of the cover against the inside of the housing wall, thus providing a sufficient surface for joining the cover to the housing wall. 
     Further preferably, an outer diameter of the skirt corresponds to the inner diameter of the housing wall. 
     It is advantageous here that the skirt rests against the inner surface of the housing wall without an air gap, so that the cover can be joined to the housing wall in a pressure-tight manner via the skirt after the cover has been displaced into the desired position without additional material. The outer diameter of the skirt can be adapted to the inner diameter of the housing wall in such a way that the cover holds itself in the desired position against the inner surface of the housing wall. 
     In another preferred embodiment of the method, the cover is joined to the housing wall mechanically, thermally and/or thermomechanically. 
     Mechanical joining may be realized, as optionally provided in a further embodiment, by engaging the housing wall with holes in the skirt of the cover, for example by pressing the housing wall into the holes in the skirt. A further advantage here is that the cover is held against rotation relative to the housing wall via the engagement of the housing wall in the holes of the skirt. Instead of pressing the housing wall into holes in the skirt of the cover, mechanical joining can also be carried out completely without holes, for example by means of crimp connections such as toxing, clinching, etc. 
     The perforation of the skirt can be carried out as part of the production of the precursor of the housing. Accordingly, in a preferred embodiment, the apparatus according to the invention comprises a perforating device for perforating the skirt of the cover. In a further embodiment of the device, the joining device may be arranged to engage the housing wall with the holes of the skirt. 
     A thermal joining may include, for example, welding the cover to the housing wall. A thermomechanical joining may comprise a combination of thermal and mechanical joining, for example, the mechanical joining may be performed with the application of heat. 
     Preferably, the joining of the cover with the housing wall is performed in the same device as the separation and displacement of the cover. 
     In another preferred embodiment of the method, providing the precursor of the housing comprises forming the cover as a bearing flange. 
     The bearing flange can be designed to accommodate a shaft. The central opening of the bearing flange can be introduced during the one-piece forming of the housing wall and the cover, i.e. before the cover is separated from the housing wall. 
     In a further preferred embodiment of the apparatus, the separating device has a separating plunger onto which the housing wall with cover can be placed, and a separating die which is designed to separate the cover from the housing wall. 
     The separating die can, for example, have a circumferential cutting edge which engages at the transition of the cover to the housing wall and shears or cuts off the housing wall from the cover by relative movement of the cutting die and separating plunger. The advantage of such a design of the separating device is that it can be integrated into a press in a simple manner. 
     The positioning device preferably has a pusher designed to displace the cover relative to the housing wall. 
     Such a pusher can also be easily integrated into a press. The pusher can, for example, engage the cover from above and displace it relative to the housing wall into the desired position after the cover has been separated from the housing wall. 
     With the method and apparatus according to the invention, a complex housing can be produced with low weight from a single blank with little use of tooling in a single apparatus or production line with little expenditure of time and cost. 
     For the purposes of the present invention, a “blank” is understood to be a sheet metal blank with the same material quality throughout, or a so-called tailored blank, i.e. a sheet metal blank which can be composed of different material qualities and sheet thicknesses, or a roll-clad sheet metal blank. The material of the blank is metallic, for example steel or aluminum. Composite materials made of different metals or of metal and plastic that can be formed are also possible. 
     Further advantages and features result from the following description and the attached drawings. 
     It is to be understood that the features mentioned above and the features to be explained below can be used not only in the combination indicated in each case, but also in other combinations or on their own, without departing from the scope of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Exemplary embodiments of the invention are shown in the drawings and are described in more detail with reference thereto hereinafter. In the drawings: 
         FIG. 1  shows a housing in a sectional view along a longitudinal axis of the housing; 
         FIG. 2  shows a precursor of the housing in  FIG. 1  in a process stage of a method of manufacturing the housing; 
         FIG. 2A  shows a blank from which the precursor is produced; 
         FIG. 3  shows another process stage of the method of manufacturing the housing in 
         FIG. 1 ; 
         FIG. 4  shows another process stage of the method of manufacturing the housing in 
         FIG. 1 ; 
         FIG. 5  shows a longitudinal section through part of a working station of an apparatus for manufacturing the housing in  FIG. 1  in a working position; 
         FIG. 6  shows a longitudinal section through the working station of the apparatus with a further part of the working station in a further working position; 
         FIG. 7  shows a longitudinal section through the working station in  FIG. 6  in a further working position; 
         FIG. 8  shows a longitudinal section through the working station in  FIG. 6  in a further working position; 
         FIG. 9  shows a longitudinal section through the working station in  FIG. 6  in a further working position; 
         FIG. 10  shows a longitudinal section through the working station in  FIG. 6  in a further working position; 
         FIG. 11  shows the part of the working station in  FIG. 5  in a further working position; and 
         FIG. 12  shows the part of the working station in  FIG. 5  in a still further working position. 
     
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       FIG. 1  shows a housing labeled with the general reference sign  10  in a longitudinal section along a longitudinal axis  12  of the housing. The housing  10  is rotationally symmetrical about the longitudinal axis  12 , although non-rotationally symmetrical geometries are also possible. 
     The housing  10  has a sleeve-shaped housing wall  14  extending around the longitudinal axis  12  and a cover  16 . The housing  10  is thus formed in multiple parts. In the present case, without limiting generality, the housing  10  is formed from two parts, namely the housing wall  14  and the cover  16 . The housing  10  may also have more than two parts. However, as will be described later, the cover  16  and the housing wall  14  have not been manufactured as separate individual parts, but have been monolithically manufactured from one blank. 
     The cover  16  is arranged at a predetermined position between a first longitudinal end  18  and a second longitudinal end  16  inside the housing wall  14  and extends transverse to the longitudinal axis  12  of the housing. The predetermined position of the cover  16  is spaced from both longitudinal ends. The cover  16  is joined to the housing wall  14 , as will be described later. 
     The housing  10  is made overall from sheet metal, for example sheet steel or sheet aluminum. Other materials, for example also hybrid materials of metal and plastic, which can be formed in forming processes, are also possible. The wall thickness of the cover  16  is shown in  FIG. 1  to be different from the wall thickness of the housing wall, but it is to be understood that the wall thicknesses of the cover  16  and housing wall  14  can also be identical. Different wall thicknesses can be realized, for example, by using a so-called tailored blank or a roll-clad blank as the starting blank. 
     The housing  10  may be, for example, a housing for an electric motor, wherein a first sub-space  22  of the interior of the housing  10  is for receiving a stator of the electric motor and a second sub-space  24  of the interior of the housing  10  is for receiving control electronics for the motor. The cover  16  separates the two compartments  22  and  24 . The cover  16  may be configured as a bearing seat as shown, in which case the cover  16  includes a bearing flange  26 . The bearing flange  26  may serve to receive a bearing shaft of the motor. 
     The cover  16  may also have different geometries in other applications of the housing  10 , i.e., the bearing flange may have a different configuration or may be omitted. 
     Due to the arrangement of the cover  16  on the inside of the housing wall  14 , i.e. in the interior of the housing  10  between the longitudinal ends  18  and  20  of the housing wall  14 , the housing  10  can be described as a complex housing. Such a complex housing can be manufactured in one piece, i.e. monolithically, not as a formed part from a single blank. 
     With reference to  FIGS. 2 to 4 , a method of manufacturing the housing  10  is described below. 
     Referring to  FIG. 2 , a precursor  28  of the housing  10  is provided. In the precursor  28  of the housing  10 , the cover  16  is formed integrally with the housing wall  14  and is arranged at one of the longitudinal ends, in this case the longitudinal end  18 , of the housing wall  14 . 
     Since the cover  16  is arranged at one of the longitudinal ends of the housing wall  14  in the precursor  28 , the precursor  28  can be manufactured in one piece, i.e., monolithically, in a conventional forming process by forming the housing wall  14  and the cover  16  together from a same blank.  FIG. 2A  shows (not to scale) a blank  29 . The blank  29  may be monolithic, a tailored blank, or roll clad. 
     As part of the forming of the precursor  28  of the housing  10 , the cover  16  is formed with a skirt  30  extending in the longitudinal direction of the housing wall  14  over a partial length of the housing wall  14  and in the circumferential direction about the longitudinal axis  12 . The skirt  30  is integrally, i.e. monolithically, connected to the housing wall  14  by a shoulder  32  in the precursor  28 . The skirt has an outer diameter D A  which corresponds to the inner diameter D I  of the housing wall  14 . The outer diameter D A  of the skirt  30  is thus smaller than the outer diameter of the housing wall  14 . 
     When forming the precursor  28  of the housing  10  from one and the same blank, the bearing flange  26  is also formed. In order to form the precursor  28  of the housing  10  from the blank  29 , the forming operations deep-drawing, reverse drawing, reversing can be applied, as well as the machining operations perforating (for the through-opening of the bearing flange  26 ) as well as a lancing and a calibrating of the edge of the through-opening can be applied. 
     In addition, the skirt  30  may be perforated as part of the fabrication of the precursor  28  of the housing  10 . Exemplary holes  34 ,  36 ,  38 ,  40 ,  42  are shown in  FIG. 2 . The holes  34 - 42  may be evenly spaced around the circumference of the skirt  30  about the longitudinal axis  12 . The function of perforating the skirt  30  will be described later. 
       FIG. 3  shows a process stage of the method of manufacturing the housing  10 , in which the cover  16  has been separated from the housing wall  14  at the precursor  28  of the housing  10  in  FIG. 2 . The separation takes place at the shoulder  32 , i.e. the transition of the cover  16  to the housing wall  14 . The separation process will be described in more detail later with reference to an embodiment of a corresponding device. 
     After separating the cover  16  from the housing wall  14 , the cover  16  is displaced relative to the housing wall  14  along the longitudinal axis  12  in accordance with an arrow  44  into the predetermined position shown in  FIGS. 1 and 4 . Based on the above dimensioning of the outer diameter of the skirt  30  relative to the inner diameter of the housing wall  14 , the outer surface of the skirt  30  fits snugly against the inner surface of the housing wall  14 , as shown in  FIG. 4 . The dimensioning of the outer diameter of the skirt  30  relative to the inner diameter of the housing wall  14  may be such that the cover  16  is held in the predetermined position according to  FIG. 4  by itself due to a corresponding frictional connection even without joining with the housing wall  14 . 
     In a next process stage according to  FIG. 4 , the cover  16  is joined to the housing wall  14 . Mechanical, thermomechanical or thermal joining processes can be used as joining process. For example, the skirt  30  can be welded to the housing wall  14 . A circumferential weld can be used to join the skirt  30  to the housing wall  14  in a pressure-tight manner. A mechanical joining of the cover  16  to the housing wall  14  may comprise engaging the housing wall  14  with the perforation (holes  34 - 42  in  FIG. 2 ), as illustrated at a location  46 . This can be accomplished, for example, by pressing the housing wall  14  into the holes  34 - 42 , which has the advantage that the housing  10  remains pressure-tight to the outside. If a pressure-tight design of the housing  10  is not required, the housing wall  14  can also be cut in the area of the perforation of the skirt  30  and material of the housing wall  14  can be bent over into the holes  34 - 42 . 
     The engagement of the material of the housing wall  14  with the perforations of the skirt  30  prevents the cover  16  from rotating with respect to the housing wall  14 . 
     Mechanical joining of the cover  16  to the housing wall  14  can also be done entirely without holes, for example by crimping joints such as toxing, clinching, etc. 
     Thermomechanical joining of the cover  16  to the housing wall  14  is also conceivable. 
     The above operations of forming the precursor  28  of the housing  10  from the blank  29 , separating the cover  16  from the housing wall  14 , displacing the cover  16  into the interior space of the housing wall  14 , and joining the cover  16  to the housing wall  16  can be carried out altogether in the same apparatus having a corresponding plurality of working stations or stages. This is described in more detail below with reference to  FIGS. 5 to 10 . 
       FIGS. 5 and 6  show a working station  50  of an apparatus for manufacturing the housing  10  in  FIG. 1 . The apparatus is described below in terms of the operations of separating the cover  16  from the housing wall  14  and positioning the cover  16  relative to the housing wall  14 . 
     The entire apparatus for manufacturing the housing  10  may further comprise a forming device for forming the cover  16  and the housing wall  14  in one piece from a same blank in one or more forming stages, as well as further working stations (e.g. perforating, calibrating, lancing) to manufacture the precursor  28  of the housing  10  according to  FIG. 2 . Since such forming devices with several forming stages and processing devices are familiar to the person skilled in the art, they are not shown in the drawing and are not described further here. 
       FIG. 5  shows a lower portion  52  of the working station  50 . The lower portion  52  includes a fixed platform or base  54 . The lower portion  52  further comprises a movable table  56  that is vertically movable according to a double arrow  58 . The lower portion  52  further comprises a gas pressure or hydraulic spring  60  having a cylinder  62  and a piston  64 . The piston  64  is also vertically movable according to the double arrow  58 . Furthermore, the lower part  52  has a separating plunger  66 , which can also be moved vertically according to the double arrow  58 . The separating plunger  66  is part of a separating device for separating the cover  16  from the housing wall  14 . The lower part  52  has an upward-mover  68  that can be moved vertically according to the double arrow  58 . 
     The device  50  further comprises an upper part  70 , which is shown in  FIG. 6  together with the lower part  52 . The upper part  70  comprises a frame or bridge  72 ,  74 . The bridge  72 ,  74  is vertically movable (according to the double arrow  58 ). The upper part  70  further comprises a cutting die  78 , which together with the separating plunger  66  forms the separating device for separating the cover  16  from the housing wall  14 . The cutting die  74  is movable according to the double arrow  58 . 
     The upper part  70  further comprises a pusher or slider  80  fixed to the bridge for displacing the cover  16  relative to the housing wall  14  after the cover  16  has been separated from the housing wall  14 . The upper portion  70  further includes gas pressure or hydraulic springs  82 ,  84  and a spacer  86 . 
     According to  FIG. 5 , the precursor  28  of the housing  10  is placed on the separating plunger  66  after it has been manufactured in the forming device of the apparatus. In this case, the separating plunger  66  is seated on the piston  64  of the gas pressure or hydraulic spring  60 , with the piston  64  in its extended position. The upward-mover  68  is in its raised position. 
     According to  FIG. 6 , the upper part  70  of the device  50  is now moved towards the lower part  52 . By moving the upper part  70  down further, the pusher  80  pushes or presses the precursor  28  of the housing as a whole over the separating plunger  66  into the position shown in  FIG. 7 . The upward-mover  68  is likewise pressed down in the process via the spacer  86 . The cutting die  78  is also moved downward. 
     In  FIG. 7 , the precursor  28  is now fully seated on the separating plunger  66 , with the inside of the cover  16  resting on the top of the separating plunger  66 . The upward-mover  68  and the frame  74  rest on the table  56 . 
       FIG. 7  shows the moment immediately before the cover  16  is separated from the housing wall  14  of the precursor  28  of the housing  10 . 
       FIG. 8  shows the separation process for separating the cover  16  from the housing wall  14  of the precursor  28  of the housing  10 . The separation of the cover  16  from the housing wall  14  takes place at the shoulder  32  between the skirt  30  of the cover  10  and the longitudinal end  18  of the housing wall  14  by a relative movement between the cutting die  78  and the separating plunger  66 . 
     The cutting die  78  is held in position and the upper gas pressure or hydraulic springs  82 ,  84  retract. 
     According to  FIG. 9 , the cover  16  is pressed down together with the separating plunger  66  by further moving the upper part  70  downward via the pusher  80  according to an arrow  88 . The housing wall  14  is held stationary in the process. Thus, by moving the upper part  70  downward in accordance with the arrow  88 , the cover  16  is displaced into the interior space defined by the housing wall  14  until the cover  16  has reached the axial predetermined position relative to the housing wall  14 , as shown in  FIG. 10 . The gas pressure or hydraulic spring  60  retracts during the displacement of the cover  16  relative to the housing wall  14 , as do the gas pressure or hydraulic springs  82  and  84 . 
     The separating plunger  66  is now in the bottom dead center position, as is the upper part  70  of the device  50 . The gas pressure or hydraulic spring  60  is locked in position. The upper part  70  is then moved away from the lower part  52 , as shown in  FIG. 11 . 
     The upward-mover  68  is then moved upward to remove the housing  10  from the separating plunger  66 , as shown in  FIG. 12 . The housing  10  can now, in a further cycle of the apparatus, be transferred to a joining device of the apparatus (not shown) in which the cover  16  is joined to the housing wall  14 , as described above with reference to  FIG. 4 . 
     However, the joining of the cover  16  to the housing wall  14  can also be performed at the process stage shown in  FIG. 11 , i.e., before the housing  10  is removed from the separating plunger  66 . 
     The above-described separation of the cover  16  from the housing wall  14  and the displacement of the cover  16  relative to the housing wall  14  into the interior of the housing wall  14  can take place in the press cycle of the device. The separating and positioning process is preceded by the forming operations, also in the press cycle. The separating and positioning operation may be followed, in the same apparatus, by the joining of the cover  16  to the housing wall. In this way, the housing  10  can be produced in the press cycle in a simple manner and with little tooling.