Patent Publication Number: US-2023143271-A1

Title: Electric Motor

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit and priority of German Application No. 10 2021 128 840.1 filed Nov. 5, 2021. The entire disclosure of the above application is incorporated herein by reference. 
     FIELD 
     The disclosure relates to an electric motor, the stator and/or the rotor has mutually opposing receiving pockets to receive a wire portion of a winding wire. 
     BACKGROUND 
     A great number of electric motors are known from the prior art. 
     The rotors and/or stators of the electric motors usually have a multiplicity of teeth. A winding space is formed between two immediately adjacent teeth where a winding wire is wound around the teeth. Thus, this forms the coil windings. 
     However, it is possible for the coil windings or the winding wires to still slip at the beginning of a winding operation. This makes it impossible under certain circumstances to optimally utilize the space available in the winding space. 
     It is therefore an object of the disclosure to overcome the aforementioned drawbacks and provide an electric motor with available space in the winding spaces of the rotor and/or stator that can be optimally utilized. Also, the highest possible slot fill factor can be achieved. 
     SUMMARY 
     This object is achieved by the combination of features according to an electric motor including a rotor and a stator with a multiplicity of teeth. A first winding space, receiving a multiplicity of coil windings wound from a winding wire, is formed between two respective immediately adjacent teeth. A second winding space connected to the respective first winding space, receiving at least one wire portion of the winding wire, is formed adjacent to at least one first winding space. The second winding space has two mutually opposing side walls in a circumferential direction about an axis of rotation of the rotor that are spaced apart from one another by a first distance on a first side of the second winding space facing in the radial direction toward the first winding space. A second distance on a second side of the second winding space faces away from the first winding space in the radial direction. A third distance is in a center portion between the first side and the second side in the circumferential direction. The second distance is equal to or greater than the first distance, and the third distance is greater than the second distance. Two receiving pockets, situated opposite one another in the circumferential direction, are formed in the center portion of the side walls in order to respectively receive the at least one wire portion of the winding wire. 
     According to the disclosure, an electric motor has a rotor and a stator, each with a multiplicity of teeth. A first winding space, receiving a multiplicity of coil windings wound from a winding wire, is respectively formed between two immediately adjacent teeth, from the multiplicity of teeth. Thus, the rotor or the stator each has a multiplicity of first winding spaces. The immediately adjacent teeth is understood to mean that there is no other tooth between the teeth in the circumferential direction. The intention is for the winding wire, which can also be referred to as coil wire, to find space in the winding space during the winding process where the winding or coil wire is wound around the teeth. Thus, the space is filled out as optimally as possible. According to the disclosure, between the mutually adjacent teeth of the at least one first winding space, a second winding space, connected to the respective first winding space, is embodied as a winding space extension of the first winding space in order to receive at least one wire portion of the winding wire. The wire portion of the winding wire, arranged in the winding space, is preferably a wire portion at the beginning or at the end of a wire that is wound around a tooth. The second winding space has two mutually opposing side walls in a circumferential direction about an axis of rotation of the rotor. The walls are spaced apart from one another by a first distance on a first side of the second winding space facing, in the radial direction, toward the first winding space. A second distance, on a second side of the second winding space, faces away from the first winding space in the radial direction. A third distance is in a center portion between the first side and the second side. The second distance is equal to or greater than the first distance. The third distance is greater than the second distance. Thus, two receiving pockets, situated opposite one another in the circumferential direction, are formed in the center portion of the side walls in order to respectively receive the at least one wire portion of the winding wire. 
     In summary, an electric motor has a rotor and a stator, each with a multiplicity of first winding spaces to receive a multiplicity of coil windings wound from a winding wire. Furthermore, at least one second winding space, which is connected to a respective first winding space, is provided as a winding space extension of the first winding space in order to receive at least one wire portion of the winding wire. Two receiving pockets, situated opposite one another in the circumferential direction, are formed in the at least one second winding space in order to respectively receive the at least one wire portion of the winding wire in a preferably fixed manner. 
     Thus, it is possible, for example, for a wire portion of a winding or coil wire to be fixed in one of the receiving pockets and then wound around a tooth to fill the first winding space. The fixation of the wire in the receiving pocket prevents the wire from slipping. 
     The coil wires or the coil wire is enabled to be received in the first winding space in a space-saving manner. Also, the layer structure formed from the coil wire in the first winding space is minimized. A high fill factor, more particularly a high slot fill factor, of the first winding space is achieved as a result. Thus, the electrical efficiency of the electric motor is increased. 
     The coil or winding wire is already fixed to the rotor and/or stator during the winding process. Thus, the wire can no longer slip and a reliable winding is also achieved. 
     In one refinement of the electric motor, the side walls each have a first portion on the first side and transition from the respective first portion into the respective center portion via a plane that extends to the second side and is oblique to the radial direction. The side walls on the second side can each have a second portion and transition from the respective second portion into the respective center portion via a plane that extends to the first side and is oblique to the radial direction. 
     In a variant of the electric motor, the oblique plane extending to the second side and the oblique plane of a side wall extending to the first side together form a centering for centering the respective at least one wire portion of the winding wire in the respective receiving pocket. 
     Further, the oblique plane extending to the second side and the oblique plane of a side wall extending to the first side are at a fourth distance from one another. This is at a first end portion where the oblique planes merge into the center portion. The fourth distance is smaller than or equal to a diameter of the smallest winding wire that can be used for the rotor or the stator. 
     In addition, the oblique plane extending to the second side and the oblique plane of a side wall extending to the first side can be at a fifth distance from one another at a second end portion opposite the first end portion. The fifth distance is greater than or equal to a diameter of a largest winding wire that can be used for the rotor or the stator. Particularly, it is exactly equal to a diameter of the largest winding wire that can be used for the rotor or stator. 
     Also advantageous is a refinement where the oblique plane, extending to the second side, and the oblique plane, of a respective side wall extending to the first side, are arranged at a predetermined opening angle relative to one another. This enables a positive fit to be established with the winding wire and the winding wire to be fixed between the oblique planes. 
     The receiving pockets are preferably each designed to secure at least one wire portion of the winding wire against displacement in the radial direction, particularly by positive locking. Thus, the coil or winding wire is fixed in particular at a beginning of the wire and is held in the receiving pocket when the wire is wound around a respective tooth. 
     Furthermore, the receiving pockets can be designed asymmetrical to one another as a function of the winding direction. 
     The position of the second winding space can also vary depending on an intended winding direction. Accordingly, in another advantageous variant of the electric motor, a center axis, extending through the second winding space, is offset from a center axis extending through the first winding space. Thus, the second winding space is arranged asymmetrically or eccentrically with respect to the first winding space. 
     The features disclosed above can be combined as required, provided this is technically possible and they do not contradict one another. 
     Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
    
    
     
       DRAWINGS 
       Other advantageous refinements of the disclosure are characterized in the subclaims and/or depicted in greater detail below together with the description of the preferred embodiment of the disclosure with reference to the figures. In the drawings: 
         FIG.  1    is a section view of a stator. 
         FIG.  2    is a section view of a second winding space. 
     
    
    
     DETAILED DESCRIPTION 
     The figures are schematic examples. The same reference symbols in the figures indicate the same functional and/or structural features. 
       FIG.  1    shows a section of an electric motor and, more precisely, a quarter of a stator  1  as a section of an electric motor. The quarter has three first winding spaces  11  between the teeth  10 . The entire stator  1  has a total of twelve first winding spaces  11  between its teeth  10 . In the quarter that is depicted and in the entire stator  1 , two second receiving spaces  20  are formed between two respective directly adjacent teeth  10 . 
     In addition to the stator  1 , that is shown as an example, other rotors or stators with other division ratios are also possible. For example, rotors and/or stators with  6 ,  9 , or more teeth and winding spaces can also be provided. 
     During winding of the coil windings  12 , the winding wire can first be guided with its wire portion  21  into the second winding spaces  20 . The wire portion  21  is secured in a receiving pocket, for example, the receiving pocket  25 , as shown in  FIG.  2   , against displacement along the radial direction R. 
     The winding wire can then be guided into the first winding space  11  belonging to the second winding space  20  and wound around the adjacent tooth  10 . 
     By virtue of the fixation in the second winding space  20 , the winding wire cannot slip in the first winding space  11 . Also, the winding wire can be guided tightly and under tension, more particularly, as it is wound around the tooth  10 . 
     This not only makes reliable winding possible, but also tight winding, which leads to a high fill factor of the winding wire in the first winding space  11 . 
       FIG.  2    shows an enlarged section of a rotor or stator  1 , with a second winding space  20 , that can be a section of the stator  1  according to  FIG.  1   . 
     Visible in  FIG.  2    are the receiving pockets  24 ,  25  that are situated opposite one another in the circumferential direction U. Each pocket receives at least one wire portion  21 . In the present case, exactly one wire portion  21 , of the winding wire, can be arranged and secured by the arrangement against displacement along the radial direction R. 
     The receiving pockets  24 ,  25  are preferably formed so that the distance A 3  between the side walls  22 ,  23  of the second winding space  20 , in the center portion, is greater than the distance A 2  and A 1 . A 2  is at a second distance here at a radially inner side. The distance A 1  is at a first distance, here at an radially outer side. 
     The preferably form-fitting fixation can be achieved particularly by virtue of the oblique planes  26 ,  27  of each receiving pocket  24 ,  25  extending toward one another. The oblique planes  26 ,  27  also serve to center and fix the wire portion  21  of the winding wire in the respective receiving pocket  24 ,  25 . 
     For this purpose, the oblique planes  26 ,  27 , of a respective receiving pocket  24 ,  25 , are at a distance A 4  from one another at their end adjoining the center portion of the pocket. Also, the oblique planes  26 ,  27  are at a distance A 5  from one another at their respective opposite end. The distance A 5  is selected such that a wire portion  21  of a winding wire is able to penetrate into the respective receiving pocket  24 ,  25  and is clamped between the oblique planes  26 ,  27 , in the respective receiving pocket  24 ,  25 , due to the convergence from the distance A 5  to the distance A 4 . 
     For this purpose, the receiving pockets  24 ,  25  also each have a depth A 6 . The depth A 6  is preferably greater than or equal to a radius of a largest winding wire that can be used for the stator  1 . 
     The depth A 6  and the distances A 4  and A 5  also have the effect that the oblique planes  26 ,  27  extend toward one another at an opening angle α. The opening angle α is selected such that the wire portion  21  can be fixed in the respective receiving pocket  24 ,  25  in a form-fitting manner. 
     The disclosure is not limited in its execution to the abovementioned preferred exemplary embodiments. Rather, a number of variants are conceivable which make use of the illustrated solution even in the form of fundamentally different embodiments. 
     The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.