Patent Document

BACKGROUND OF THE INVENTION 
       [0001]    The invention relates to an electric motor. 
         [0002]    Electric motors comprising rotor guide means and housing elements are already known. It is also known that the housing elements are produced by means of diecasting, in particular zinc, aluminum or magnesium diecasting. Diecasting is used to produce housing elements that have sufficient stability. Housing elements formed by diecasting, however, are heavy and expensive. 
       SUMMARY OF THE INVENTION 
       [0003]    The electric motor according to the invention has the advantage of a simplified and thus economical production of the electric motor. A further advantage is considered to be the fact that, due to the use of a bent sheet metal part, in particular a deep-drawn sheet metal as housing element, less material is required compared to the diecast housing element, and therefore the weight of the housing element and of the electric motor can be reduced. Furthermore, the production of a bent sheet metal part is less complex and thus more convenient compared to the production of a cast part. 
         [0004]    It is particularly advantageous that the carrier means has a first recess, which in particular is continuous. Furthermore, the rotor guide means is mounted in the first recess in the carrier means in a rotationally fixed or rotatable manner. By accommodating the rotor guide means in a recess in the carrier means, the stability of the electric motor can be increased. It is also advantageous that the assembly and thus the production of the electric motor can be simplified. 
         [0005]    An advantageous development is characterized in that the rotor guide means and the carrier means are connected, in particular in a form-locked and/or force-locked manner. Due to the force-locked and/or form-locked connection of the carrier means to the rotor guide means, a rotationally fixed connection between the carrier means and the rotor guide means is achieved. A rotationally fixed connection of the carrier means to the rotor guide means is advantageous for certain electric motor mountings, in particular external rotor motors. In order to increase the stability, it is also advantageous for the rotor guide means to be press fitted or cast in into the first recess in the carrier. 
         [0006]    An advantageous development is that the carrier means has a bearing element. In particular, the bearing element is arranged in the first recess in the carrier means. The bearing element guides, in particular supports, the rotor guide means rotatably relative to the carrier means. The rotatable mounting of the rotor guide means relative to the carrier means is advantageous for electric motors which have an internal rotor in relation to the stator. 
         [0007]    A development of the invention is that the electric motor has a stator. The stator is in particular connected to the carrier means in a form-locked and/or force-locked manner. Due to the form-locked and/or force-locked connection between the stator and the carrier means, forces or torques that occur between the rotor and the stator during operation or standstill can be optimally transferred. 
         [0008]    It is particularly advantageous that the carrier means has an orientation means which orientates, in particular centers, the stator relative to the rotor guide means. The assembly of the individual elements of the motor is simplified by the orientation means on the carrier means, which results in an accelerated production of the electric motor. The carrier means can advantageously have an orientation means which implements an orientation relative to the housing element. 
         [0009]    An advantageous development of the invention is that the electric motor has a connection means, wherein the connection means connects the carrier means to the housing element and/or a stator in a form-locked and/or force-locked manner. Connection of the carrier means to the housing element and/or the stator is possible in a simple manner by the connection means. 
         [0010]    It is also advantageous that the connection means is formed as a screw, in particular as a self-tapping screw. It is also advantageous that the carrier means has a second recess, which in particular is continuous, wherein the connection means and the second recess cooperate, the connection means in particular engaging in the second recess. The stability of the electric motor is improved by the cooperation of the second recess in the carrier means with the connection means. 
         [0011]    An advantageous development is that the housing element has a recess, wherein the recess cooperates with the connection means. The stability of the electric motor is improved by the cooperation of the recess in the housing element with the connection means. Elements of the electric motor can also be connected to the housing element. It is advantageous in particular when the recess is formed as a passage in the sheet metal of the housing element. The design of the recess as a passage enables a simple production of a recess that enables the best possible, in particular stable connection between the housing element and the connection means. 
         [0012]    It is advantageous that the carrier means has at least one spoke. It is also advantageous when the carrier means has a middle element, wherein the middle element has a first recess. The spoke is arranged on the middle element. The at least one spoke, together with the middle element, increases the stability of the carrier means. Forces or torques created at standstill or during operation can be optimally absorbed or emitted by the carrier means. 
         [0013]    It is particularly advantageous that the spoke has a second recess, which in particular is continuous, for connection of the carrier means to the housing element and/or the stator. The second recess cooperates with a connection means, in particular a screw, preferably a self-tapping screw. The arrangement of a second recess in the spoke and the cooperation of the second recess with a connection means enables an optimal absorption and emission of forces or torques into or from the connection means. 
         [0014]    A preferred development of the invention is that the electric motor has control electronics, and the control electronics are arranged on the housing element, in particular the housing element is part of the housing of the control electronics. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    Exemplary embodiments of the invention are illustrated in the drawings and will be explained in greater detail in the following description. In the drawings: 
           [0016]      FIG. 1  shows a sectional view through an electric motor  1 , 
           [0017]      FIG. 2  shows a housing element formed by means of diecasting, 
           [0018]      FIG. 3  shows a perspective view of a housing element according to the invention formed from a deep-drawn sheet metal part, 
           [0019]      FIG. 4  shows a perspective view of a carrier means according to the invention, 
           [0020]      FIG. 5  shows an electric motor with a housing element, a carrier means, a stator, and a rotationally fixed rotor guide means, 
           [0021]      FIG. 6  shows an electric motor with a housing element, a carrier means, a stator, and a rotationally fixed rotor guide means in the assembled state, 
           [0022]      FIG. 7  shows an electric motor with a housing element, a carrier means, a stator, and a rotatably mounted rotor guide means, 
           [0023]      FIG. 8  shows an electric motor with a housing element, a carrier means, a stator, and a rotatably mounted rotor guide means in the assembled state, 
           [0024]      FIG. 9  shows a further exemplary embodiment with a bearing element in the stator, and 
           [0025]      FIG. 10  shows the further exemplary embodiment in the assembled state. 
       
    
    
     DETAILED DESCRIPTION 
       [0026]      FIG. 1  shows a sectional view through an electric motor  1 , in particular an external rotor electric motor. The electric motor  1  comprises a stator  20  with stator coils  22 , and comprises a rotor  24  and a rotor guide means  25 . The rotor guide means  25  guides the rotor  24 , wherein the rotor  24  is arranged rotatably relative to the stator  20 . The rotor guide means is mounted rotatably relative to the stator  20  by the bearing element  48 . The rotor  24  comprises magnets  26 . 
         [0027]    Electronically commutated electric motors belong to the group of synchronous DC motors, that is to say an electromagnetic rotary field generated by stator coils  22  has the same rotational speed as a rotor  24 . In order to generate a rotational movement, the stator coils  22  must be energized in a specific sequence. The generated magnetic field in the stator coils  22  leads to an attraction or repulsion of the magnets  26  of the rotor  24  and therefore to a rotation of the rotor  24 . This sequence is generated by electronics, in particular control electronics. 
         [0028]    The electronics are arranged on a housing element  10  (see  FIGS. 2-10 ) or in a housing  5  for protection against or dissipation of heat. It is advantageous when the electronics are arranged as close as possible to the stator coils  22  in order to keep line elements between the electronics and the stator coils  22  as short as possible. The radiation of electromagnetic emission can also be reduced by the arrangement of the electronics close to the stator coils. 
         [0029]    The rotor  24  is arranged rotatably relative to the stator  20  via the rotor guide means  25 . During operation or at standstill, forces and torques act between the rotor  24  and the stator  20 . These forces and torques also act on devices or elements connected to the electric motor  1 . If the stator  20  is mounted in particular on a housing element  10 , the forces and torques will be transferred thereto. Conversely, forces and torques are transferred from the housing element  10  to the stator  20  and/or the rotor  24 . For this reason, the rotor  24 , the stator  20 , and further elements of the electric motor  1  must have sufficient stability to be able to absorb and/or transfer the forces or torques occurring at standstill or during operation. 
         [0030]    By way of example, the housing element  10  is part of a housing  5 , in particular a casing, a transmission, electronics, or a fan housing. The housing element  10  serves in particular to secure the electric motor  1  to a casing, a transmission, electronics, or a fan housing. Forces or torques from outside the electric motor  1  act on the housing element  10 . The housing element  10  also transfers forces which for example act on the rotor  24  to the surrounding environment, in particular a casing, a transmission, or a fan housing. 
         [0031]    The purpose of the housing element  10  is, amongst other things and besides the heat dissipation and protection of the electronics, the rotor  24 , or the stator  20 , to also transfer forces that act on the electric motor  1  from outside the electric motor  1 , and vice versa. 
         [0032]    In the prior art, housing elements  10  produced from diecast aluminum are used in accordance with  FIG. 2 . The housing elements  10  at the same time form a sort of motor flange for the electric motor  1 . The housing element  10  according to the prior art has a complex geometry for optimal force absorption and distribution. The housing elements  10  also have further geometries, such as securing holes for securing electronics, the stator and/or the housing in fan casings. With aluminum diecast parts, complex geometries that can absorb high forces and torques can be provided. For this reason, housing elements  10  in the prior art are realized as aluminum diecast parts. 
         [0033]      FIG. 2  shows a diecast housing element  10  according to the prior art. The shaft  30  of the electric motor  1  is fixedly connected to the housing element  10 . The shaft  30  is connected to the housing element  10  in a form-locked and force-locked manner. The shaft  30  is in particular molded into the housing element  10 . The housing element  10  according to  FIG. 1  is thus formed in one part. In particular, a disadvantage of a housing element  10  produced by means of diecasting is constituted by the short die service lives of a diecasting die as well as the necessary and complex/costly deburring and cleaning processes of an aluminum diecast part, i.e. the housing element  10 , which are absolutely necessary for the installation of the electronics and for implementation of a liquid-tight concept. In addition, the placement of the shaft  30  in the diecasting die increases the cycle time. In addition, the packing volume of the housing element  10  is adversely affected by the injected shaft  30 . This spatial requirement leads to increased transport costs. 
         [0034]      FIG. 3  shows a housing element  10  according to the invention. The housing element  10  is formed as a deep-drawn sheet metal part, in particular as a deep-drawn sheet metal part made of aluminum. The housing element  10  according to the invention is produced from a sheet metal by means of deep drawing. The housing element  10  is part of a housing  5 . In particular, housing elements  10 , in particular two such housing elements, form a housing  5  for the stator  20  and the rotor  24  of the electric motor  1  or a housing  5  for electronics, which control the electric motor. The electronics and the stator  20  are advantageously arranged on the housing element  10 , in particular are connected thereto, and preferably secured thereto. The housing element  10  thus also serves as a connector of the individual elements, such as the rotor  24 , stator  20 , and rotor guide means  25  of the electric motor  1 . 
         [0035]    The housing element  10  has at least one recess  12 , in particular a passage or a bore. The recess  12  cooperates with a connection means  50  (see  FIG. 5 ). The connection means  50  serve to connect, in particular to mount the elements of the stator  20  on the housing element  10 , and vice versa. By way of example, the housing element  10  in  FIG. 3  has three recesses  12 . 
         [0036]    In accordance with one embodiment, the housing element  10  according to  FIG. 3  has a rotor guide means recess  14 . The rotor guide means  25  can be partially arranged in the rotor guide means recess  14  or guided thereby. The screw heads in the openings  16  serve to secure a further housing element  11  to the housing element  10  or to mount the housing element  10  on an external element, in particular a casing, a transmission, or a fan housing. 
         [0037]      FIG. 4  shows a carrier means  40  according to the invention. The carrier means  40  is produced in particular as a sintered part. The carrier means  40  according to  FIG. 4  has three spokes  42  by way of example. In accordance with the invention, the carrier means  40  can have an arbitrary number of spokes  42 , in particular one, two, four, five or six. The carrier means  40  also comprises a middle element  41 . The spokes  42  are arranged around the middle element  41  in a star-shaped manner. The spokes  42  extend radially outwardly here. The spokes  42  and the middle element  41  are formed in one piece. The carrier means  40  comprises a first recess  44 . A rotor guide means  25  is arranged in the first recess  44 . The rotor guide means  25  can be connected to the carrier means  40  in a rotationally fixed or rotatable manner. A rotor guide means  25  connected in a rotationally fixed manner is referred to as a spindle, and a rotor guide means  25  arranged rotatably is referred to as a shaft. 
         [0038]    It is particularly advantageous that the carrier means  40 , which in particular is formed as a sintered part, has a coefficient of expansion substantially identical to that of a rotor guide means  25  made of steel. 
         [0039]    In accordance with the exemplary embodiment in  FIG. 4 , the rotor guide means  25  passes through the carrier means  40 . The rotor guide means  25  protrudes in the assembled state into the rotor guide means recess  14  in the housing element  10 . 
         [0040]    The spokes enable an improved distribution of the force over the housing element  10 , and vice versa. The spokes  42  have a length dependent on the torque and the force. The spokes  42  each have a second recess  45 . The second recess  45  is arranged at the end of the corresponding spoke  42  averted from the rotor guide means  25 . The spokes  42  also have a spoke head  46 . The spoke head  46  comprises the second recess  45 . The spoke head  46  is connected to the middle element  41  via a spoke rib  43 . The spoke heads  46 , the spoke ribs  43 , and the middle element  41  of the carrier means  40  are formed in one piece. 
         [0041]    The spokes  42  are advantageously arranged at a uniform angle to one another. By way of example, in the case of a carrier means  40  having three spokes  42 , the spokes  42  are arranged at an angle of 120 degrees to one another. In the case of a carrier means  40  having four spokes  42 , the spokes  42  are arranged at an angle of 90 degrees to one another. By means of a uniform arrangement of the spokes  42 , forces that act on the housing element  10  via the rotor guide means  25  and vice versa can be distributed in the best possible way. 
         [0042]      FIG. 5  shows a stator  20 , a rotor guide means  25 , a carrier means  40 , a housing element  10 , and a connection means  50  of an electric motor  1  according to the invention. The carrier means  40  and the housing element  10  are formed in a manner corresponding to the carrier means  40  from  FIG. 4 . The stator  20  has recesses  27 , in particular continuous recesses  27 , preferably continuous bores. The recesses  27  in the stator  20  are arranged in line with the second recesses  45  in the carrier means  40  and the recesses  12  in the housing element  10 . A connection means  50  is inserted, in particular screwed, into the recesses  27  in the stator  20 , the second recesses  45  in the carrier means  40 , and the recess  12  in the housing element  10 . 
         [0043]    The connection means  50  is formed in particular as a screw with a thread, advantageously as a self-tapping screw. Self-tapping screws or thread-forming screws are connection means  50  which, when screwed into a core hole, produce their female thread themselves by chipless shaping. The connection means  50  provides a form fit and/or a force fit between the stator  20 , the carrier means  40 , and the housing element  10 . 
         [0044]    In accordance with the invention, the connection means  50  can provide a form fit and/or force fit between the carrier means  40  and the housing element  10 . 
         [0045]      FIG. 6  shows an exemplary embodiment of an electric motor  1  according to the invention in a partly assembled state. The stator  20 , the carrier means  40 , and the housing element  10  are connected to one another by means of a connection means  50 . The connection means  50  is formed in particular as a self-tapping screw. The connection means  50  comprises a screw head  51 . An annular contact face  52 , which in the illustrated exemplary embodiment bears against the stator  20 , is disposed on the underside of the screw head  51 . The contact face  52  is adjoined by a screw shank  53  having a thread  44 , which in particular is a self-tapping thread. The screw shank  53  engages in the recess  27  in the stator  20  and in the recess  45  in the carrier means  40 . The connection means  50  is fixed in the recess  12  of the housing element  10  via the produced female thread. The recess  27  in the stator  20  and the recess  45  in the carrier means  40  are advantageously minimally larger than the screw shank  53 . The recess  12  in the housing element  10  is smaller than the self-tapping thread  44  of the self-tapping screw  50 . 
         [0046]    In accordance with a further embodiment the recess  12  in the housing element  10  has a thread, and the connection element  50  has a thread corresponding to the thread of the housing element  10 . 
         [0047]    In accordance with one embodiment the recess  12  of the housing element  10  is formed as a passage. 
         [0048]      FIG. 6  shows a housing element  10  with a rotor guide means recess  14  by way of example. A rotor guide means recess  14  in the housing element  10  is necessary when the rotor guide means  25  passes through the carrier means  25 . The rotor guide means  14  is arranged in the rotor guide means recess  14 . The rotor guide means recess  14  is deep-drawn and has a rotor guide means recess base  15 . The rotor guide means  14  bears against the rotor guide means recess base  15 . 
         [0049]      FIG. 7  illustrates a further embodiment according to the invention. The carrier means  40  comprises, by way of example, a middle element  41  on which three spokes  42  are arranged. The middle element  41  and the spokes  42  are formed in one piece. The carrier element  40  is advantageously formed as a sintered part. The spokes  42  have second recesses  45  at their ends averted from the middle element  41 . In particular, connection means  50  for mounting, in particular securing the carrier means  40  on the housing element  10  can be arranged in the recesses  45 . Furthermore, the spokes  42  have an annular surround  46  of the second recesses  45 . The angular surrounds  46  are connected to the middle element  41  via a spoke rib  43 . The angular surrounds, together with second recesses  45 , form a spoke head  46 . The annular surround of the second recesses  45 , the spoke ribs  43 , and the middle element  41  are formed in one piece. The carrier means  40  can have an arbitrary number of spokes  42  in accordance with the invention. The arrangement of the spokes  42  is dependent on the number of spokes  42 . 
         [0050]    In accordance with  FIG. 7  the spokes  42  are arranged in particular uniformly relative to one another. By way of example, in the case of three spokes  42 , the three spokes  42  are arranged at an angle of 120 degrees to one another. 
         [0051]    The carrier means  40  comprises a first recess  44 . One or more bearing elements  48  can be arranged in the first recess  44 . In accordance with  FIG. 7  a first bearing element  48   a  and a second bearing element  48   b  are arranged in the recess. The first and the second bearing element  48   a  and  48   b  support the rotor guide means  25  rotatably relative to the carrier means  40 . The bearing element  48   a / 48   b  is formed in particular as a ball bearing or plain bearing. The bearing elements  48   a  and  48   b  are each arranged in the first recess  44  of the carrier means  40 . The bearing element  48   a  is arranged in the longitudinal direction at an end, in particular the upper end, of the carrier means  40 . The bearing element  48   b  is arranged in the longitudinal direction at the end of the carrier means  40  opposite the upper end, in particular at the lower end. The inner diameter of the first recess  44  corresponds in the region of the arranged bearing elements  48   a  and  48   b  to the outer diameter of the bearing elements  48   a  and  48   b.  A stop in the recess  47  prevents a shifting of the bearing element  48   a  in the carrier means  40 . A corresponding stop for the second bearing element  48   b  is not shown in the drawing. 
         [0052]    The carrier element  40  is connected to the housing element  10  via the connection means  50 . The carrier means  40  is secured to the housing element  10 . The housing element  10  has recesses  12 . The recesses  12  are formed in particular as a passage. They also have an inner diameter smaller than the outer diameter of the connection means  50 . The connection means  50  is formed in particular as a self-tapping screw having a self-tapping thread  44 . The thread  44  of the self-tapping screw  44  creates its female thread itself by chipless shaping. 
         [0053]    In accordance with a further embodiment the recesses in the housing element  10  have threads. These threads cooperate with the thread of the connection means  50 , in particular of the screws. 
         [0054]    A partly assembled electric motor  1  is illustrated in  FIG. 8 . The electric motor  1  comprises a stator  20 . The stator  20  comprises a stator core  21 , which in particular is formed as a laminated core. The stator core  21  comprises stator teeth. The stator teeth comprise a stator tooth shaft and a stator tooth head. Stator coils  22  are wound around the stator tooth shafts. The stator core is advantageously overmolded by a thin plastic layer  23 . The plastic layer  23  serves to protect the stator coils  22  and to mount the stator coils  22  on the stator core  21  in an improved way. 
         [0055]    In accordance with  FIG. 7  the carrier element  40  has a first recess  44 , in which a bearing element  48  is arranged. The bearing element  48  supports or guides the rotor guide means  40  rotatably relative to the carrier means  40 . The rotor (not shown) is connected to the rotor guide means  40  in a rotationally fixed manner. The rotor has at least one element, wherein the element consists for example of a ferromagnetic material, a magnetic material, or a material that has magnetic properties. The magnetic force generated by energizing the stator  20  acts on the elements of the rotor. A torque is produced as a result of the magnetic force and rotates the rotor. The elements of the rotor are arranged opposite the stator coils  22  in the radial direction. The rotor rotates about the stator  20 . The electric motor  1  is formed as an external rotor motor in accordance with  FIG. 8 . 
         [0056]    The connection means  50  are formed in particular as screws, advantageously as self-tapping screws. The connection means  50  connect the stator  20 , the carrier means  40 , and the housing element  10  to one another in a force-locked and/or form-locked manner. 
         [0057]      FIG. 9  shows a further embodiment of an electric motor  1  according to the invention. The carrier means  40  has a first recess  44 . The first recess  44  is arranged in the middle element  41  of the carrier means  40 . A bearing element  48   b  is arranged inside the first recess  44 . The carrier means  40  also has three spokes  42 . The three spokes  42  each have a spoke rib  43  and a second recess  45 . The second recess  45  is arranged in the spoke head  46 . The spokes  42  and the middle element  41  are formed in one piece. The carrier means  40  is manufactured in particular as a sintered part. 
         [0058]    A second bearing element  48   b  is arranged inside a recess  27  in the stator  20 . A tolerance ring  28  is arranged between the stator  20  and the bearing element  48   b.  The tolerance ring enables the compensation of tolerances in the production of the stator  20  and the bearing element  48 . The stator  20  and the bearing element  48  also have different coefficients of expansion. The different coefficients of expansion can also be compensated for by the tolerance ring  28 . 
         [0059]    The connection means  50 , in particular screws, connect the stator  20 , the carrier means  40  and the housing element  10 . The connection means  50  enable the stator  20  and the carrier means  40  to be secured to the housing element  10 . 
         [0060]    In accordance with one embodiment the carrier means  40  comprises an orientation means  49 . An orientation means  49  is arranged on each spoke head  46  in  FIG. 9 . The carrier means  40  thus has three orientation means  49 . The three orientation means  49  engage in recesses in the stator  20  and orientate them relative to the carrier means  40 . The stator  20  is thus oriented relative to the rotor guide means  25 . 
         [0061]      FIG. 10  shows the electric motor  1  described in  FIG. 9  in the assembled state. The stator  20  is connected by means of the connection means, in particular the screws  50 , to the carrier means  40  and the housing element  10  in a form-locked and force-locked manner, in particular in a rotationally fixed manner. The bearing element  48   b  is also arranged in the recess in the stator  20 . The tolerance ring  28  is arranged between the bearing element  48   a  and the stator  20 . 
         [0062]    In accordance with a further exemplary embodiment the connection means  50  is embodied in the form of rivets or clips. In accordance with the invention, the connection of the carrier means  40  to the housing element  10  can also be implemented in particular by means of welding, soldering or adhesive bonding. 
         [0063]    In accordance with a further exemplary embodiment the housing element  10  is part of an electric motor housing  5  surrounding the electric motor  1 . 
         [0064]    In accordance with a further embodiment the carrier means  40  is formed as a sheet metal part, in particular a deep-drawn sheet metal part, or as a diecast part, in particular made of zinc, aluminum or magnesium. 
         [0065]    The connection means  50  advantageously has a seal, in particular a microencapsulation. The seal prevents an exchange of fluids between the region of the stator and the region of the housing element  10 . A seal of this type is important in particular when the housing element  10  is part of a housing  5  that surrounds electronics. 
         [0066]    In accordance with further embodiments the spokes  42  are arranged at an angle of from 30 to 180 degrees to one another. The angle is dependent on the number of spokes  42 . The angles between the spokes  42  are advantageously substantially identical. The angle varies depending on the number of spokes  42 , advantageously in steps/increments of 30 degrees. By way of example, the angle between the spokes  42  in the case of a carrier means  40  having four spokes  42  corresponds to 90 degrees, and in the case of a carrier means  40  having  12  spokes the angle corresponds to 30 degrees. A carrier means  40  having substantially identical angles between the spokes  42  has improved magnetic properties. 
         [0067]    An electric motor  1  according to the invention can be embodied in particular as a brush motor, brushless motor, asynchronous motor, synchronous motor, electrically commutated motor, or as a stepper motor.

Technology Category: 7