Abstract:
A high-torque motor device, comprising: a shaft, an electromagnetic unit with a stator and a rotor, and a single-stage planetary gear unit set onto the rotor. The single-stage planetary gear unit is provided with a planetary gear disk firmly sleeved onto the shaft, a plurality of planetary gears pivoted onto the planetary gear disk, an internal ring gear meshed with the planetary gear, and a sun gear fixed onto the rotor and meshed with the planetary gear. The present invention allows a single shaft between the motor and planetary gear unit, thus shortening the axial length of entire device and further guaranteeing the assembly precision of parts. This structure can be applied to motor and generator.

Description:
CROSS-REFERENCE TO RELATED U.S. APPLICATIONS 
       [0001]    Not applicable. 
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not applicable. 
       NAMES OF PARTIES TO A JOINT RESEARCH AGREEMENT 
       [0003]    Not applicable. 
       REFERENCE TO AN APPENDIX SUBMITTED ON COMPACT DISC 
       [0004]    Not applicable. 
       BACKGROUND OF THE INVENTION 
       [0005]    1. Field of the Invention 
         [0006]    The present invention relates generally to a gear motor, and more particularly to a gear motor or gear generator with high torque. 
         [0007]    2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98. 
         [0008]    In the application fields of electric tools or power-operated machines, the gear motors combined with planetary gear set could reduce greatly the dimension of motors, and realize high-power and high torque due to the design of high reduction ratio. 
         [0009]    The currently available gear motors combined with planetary gear set are designed in such a manner that the gear set and internal motor are separated, and radial air-gap motors with longer shafts are widely used, making it difficult for the occasions placing special requirements for the axial space. 
         [0010]    For example, as illustrated in U.S. Pat. No. 5,123,300, a phase adjustment mechanism combining disc motor with planetary gear set is used for phase adjustment of output and input shafts, namely, with the traditional design of declutch shaft and declutch gear, the gear motor has shortcomings with respect to the axial length or alignment precision of components. To improve the poor alignment precision, some technologies are developed in the industry, e.g.: U.S. Pat. No. 6,966,391 illustrates a design that can improve the alignment precision of front and rear shafts; however, due to different rotation speeds of the motor shaft and final output shaft, the high-precision design with a single through-going shaft cannot be realized, leading to rather complex design of the relevant shaft seal structure (e.g.: U.S. Pat. No. 7,182,709). 
         [0011]    There is still a room for improvement of the axial dimension or alignment precision of components of the gear motor combined with planetary gear set. 
       BRIEF SUMMARY OF THE INVENTION 
       [0012]    The primary objective of the present invention is to provide a thin-profile gear motor that combines with a planetary gear set and reduces greatly the axial dimension while featuring high alignment precision of components. 
         [0013]    Hence, the gear motor of the present invention comprises: a shaft, an electromagnetic unit and a single-stage planetary gear unit. 
         [0014]    The electromagnetic unit is provided with a stator and a rotor pivoted onto the shaft for rotation in relation to the stator. 
         [0015]    The single-stage planetary gear unit is provided with a planetary gear disk fixed onto and coaxially rotated with the shaft, a plurality of planetary gears pivoted rotarily onto the planetary gear disk, an internal ring gear fixed in relation to the stator of the electromagnetic unit and meshed with the planetary gear, and a sun gear fixed onto the rotor of the electromagnetic unit, coaxially rotated with the rotor, and meshed with the planetary gear. 
         [0016]    The other purpose of the present invention is to provide a thin-profile gear motor that combines with a multi-stage planetary gear set and reduces greatly the axial dimension while featuring high alignment precision of components. The gear motor comprises: a shaft, an electromagnetic unit and a multi-stage planetary gear unit. 
         [0017]    The electromagnetic unit is provided with a stator and a rotor pivoted onto the shaft for rotation in relation to the stator. 
         [0018]    The multi-stage planetary gear unit is provided with a first planetary gear disk fixed onto and coaxially rotated with the shaft, a plurality of first planetary gears pivoted rotarily onto the first planetary gear disk, a first internal ring gear fixed in relation to the stator and meshed with the first planetary gear, a first sun gear meshed with the first planetary gear, a second planetary gear disk sleeved rotarily onto the shaft and also sleeved by the first sun gear, a plurality of second planetary gears pivoted rotarily onto the second planetary gear disk, a second internal ring gear fixed in relation to the stator and meshed with the second planetary gear, and a second sun gear fixed onto the rotor of the electromagnetic unit and coaxially rotated with the rotor, and also meshed with the second planetary gear. 
         [0019]    The efficacies of the present invention lie in that, the sun gear is directly sleeved onto the rotor, such that main rotating parts can rotate on the same shaft. With the design of such a single shaft, it is possible to shorten the axial length of entire device and guarantee the concentricity of parts so as to improve the assembly precision of parts. 
         [0020]    Based on above-specified design, the gear motor of the present invention has the following advantages: 
         [0021]    High-Precision Design: 
         [0022]    The sun gear  44  is directly incorporated onto the rotor  32 , such that a single shaft  2  is used as the basis of rotation and alignment of various parts, and main rotating parts have the same rotating axis; hence, the concentricity of rotating parts can be more accurately controlled to realize high-precision manufacturing and operation while improving poorer manufacturing precision or the problems requiring complex shaft seal and alignment mechanism. 
         [0023]    Excellent Structural Robustness: 
         [0024]    With the structural design of single shaft  2 , various parts could be structured more robustly, so as to ensure excellent structural robustness with the radial support of the bearing unit  5 . 
         [0025]    Compact Design: 
         [0026]    With the compact configuration of various parts and the design of incorporating the sun gear  44  onto the rotor  32 , the axial length of the entire mechanism is shortened greatly for the compactness, so the present invention can be widely applied to the products to be arranged in confined space and requiring high torsion output (e.g.: in-wheel motor). 
         [0027]    Application to Auxiliary Drive: 
         [0028]    Owing to the design of single shaft  2 , the present invention can also be applied to auxiliary drive, e.g. HEV. 
         [0029]    To sum up, the gear motor of the present invention allows to sleeve directly the sun gear  44  onto the rotor  32 , such that the rotation and alignment of main rotating parts can be guaranteed by a single shaft  2  to ensure the assembly precision, shorten greatly the axial length and enhance the structural robustness of entire mechanism. 
         [0030]    Although the invention has been explained in relation to its preferred embodiment, it is to be understood that many other possible modifications and variations can be made without departing from the spirit and scope of the invention as hereinafter claimed. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0031]      FIG. 1  is a partial sectional view illustrating partial section of the first preferred embodiment of the gear motor of the present invention; 
           [0032]      FIG. 2  is a 3D exploded view illustrating the first preferred embodiment; 
           [0033]      FIG. 3  is a partial sectional view illustrating partial section of the second preferred embodiment of the gear motor of the present invention; 
           [0034]      FIG. 4  is a partial sectional view illustrating partial section of the third preferred embodiment of the gear motor of the present invention; and 
           [0035]      FIG. 5  is a partial sectional view illustrating partial section of the fourth preferred embodiment of the gear motor of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0036]    The features and the advantages of the present invention will be more readily understood upon the following detailed description of four preferred embodiments of the present invention with reference to the accompanying drawings. 
         [0037]    Prior to detailed description of the present invention, similar parts are represented by the same reference numeral. 
         [0038]    Referring to  FIG. 1  in collaboration with  FIG. 2 , the first preferred embodiment of the gear motor of the present invention comprises: a casing body  1 , a shaft  2 , an electromagnetic unit  3 , a single-stage planetary gear unit  4  and a bearing unit  5 . It is worthy to note that, as the structure is symmetrical, only a half of structure is illustrated in  FIG. 1  (and subsequent sectional views). 
         [0039]    The casing body  1  is provided with a casing  11  and a holding space  12  defined by the casing  11 . The casing  11  is provided with a first casing portion  111  and a second casing portion  112  connected oppositely to define essentially the holding space  12 . In addition, the first and second casing portions  111 ,  112  are also configured with a fixed structure, e.g.: a hanger with screwed hole, used to fasten the first and second casing portions  111 ,  112  onto the available carrier. 
         [0040]    The shaft  2  is set into the holding space  12  and extended out of the first and second casing portions  111 ,  112  of the casing  11 . The first and second casing portions  111 ,  112  of the casing  11  can rotate in relation to the shaft  2 . It is worthy to note that, the following wordings of “radially” and “axially” are based on the shaft  2 . 
         [0041]    The electromagnetic unit  3  is provided with a stator  31  radially fixed onto the first casing portion  111  of the casing  11  and located in the holding space  12 , and a rotor  32  located in the holding space  12 , concentrically pivoted onto the shaft  2  and rotated in relation to the stator  31 . In this preferred embodiment, the stator  31  is provided with an iron core  311  radially fixed onto the first casing portion  111 , and a coil assembly  312  radially wound onto the iron core  311 . The rotor  32  is provided with a pivoting portion  321  concentrically pivoted onto the shaft  2 , an extension  322  radially extended from the pivoting portion  321 , an assembly portion  323  axially extended from the end of the extension  322  and moved around the end of the iron core  311 , and a magnet  324  set laterally onto the assembly portion  323  facing the iron core  311  and keeping a spacing with the end of the iron core  311 , so as to form electromagnetic reaction with the iron core  311  and coil assembly  312 . In this preferred embodiment, the coil assembly  312  is wound onto the iron core  311 , but not limited to this configuration, and the coil assembly  312  can also be routed to flexible printed circuit board. 
         [0042]    The single-stage planetary gear unit  4  is provided with a planetary gear disk  41  located in the holding space  12 , sleeved firmly onto the shaft  2  and coaxially rotated with the shaft  2 , a plurality of planetary gears  42  (only a single one shown in  FIG. 1 ) rotarily pivoted onto the planetary gear disk  41 , an internal ring gear  43  fixed onto the first/second casing portion  111 ,  112 , located in the holding space  12  and meshed with the planetary gear  42 , and a sun gear  44  coaxially sleeved onto the pivoting portion  321  of the rotor  32 , coaxially rotated with the pivoting portion  321 , and meshed with the planetary gear  42 . 
         [0043]    The bearing unit  5  is provided with a first bearing  51  sleeved onto the shaft  2  and located between the shaft  2  and the first casing portion  111  of the casing  11 , a second bearing  52  sleeved onto the shaft  2  and located between the shaft  2  and the pivoting portion  321  of the rotor  32 , a third bearing  53  sleeved onto the planetary gear disk  41  and located between the planetary gear disk  41  and the second casing portion  112  of the casing  11 , a plurality of fourth bearings  54  (only a single one shown in  FIG. 1 ) set onto the planetary gear disk  41  correspondingly to the planetary gear  42 , so as to support separately the planetary gear  42 , and a fifth bearing  55  pivoted onto the pivoting portion  321  of the rotor  32  and located between the pivoting portion  321  and the first casing portion  111  of the casing  11 . In this preferred embodiment, the first-fifth bearings  51  - 55  are implemented in the form of ball bearing. 
         [0044]    The rotor  32 , planetary gear disk  41  and shaft  2  rotate along the same rotating axis of the shaft  2 . After the coil assembly  312  of the stator  31  of the electromagnetic unit  3  is energized, a magnetic field will be generated together with the iron core  311 , such that the magnetic repulsion could drive the magnet  324  on the assembly portion  323  to couple with the extension  322 , pivoting portion  321 , and also enable rotation of the sun gear  44  on the pivoting portion  321  along the rotating axis of the shaft  2 . In such a case, the planetary gear  42  meshed with the sun gear  44  is driven to rotate along its own axis. As the planetary gear  42  is meshed with the internal ring gear  43  kept in relative static status, the planetary gear disk  41  starts to rotate along the rotating axis of the shaft  2  (namely, the planetary gear  42  could rotate along its own axis and also along the axis of the shaft  2 , so as to drive the planetary gear disk  41 ). Meanwhile, the shaft  2  connected coaxially with the planetary gear disk  41  is driven by the planetary gear disk  41  to rotate along its own axis. As such, an intended reduction ratio could be obtained from the preset gear ratio of the planetary gear  42 , sun gear  44  and internal ring gear  43 , thus allowing the shaft  2  to generate high torsion output. 
         [0045]    According to aforementioned description, the gear motor is used as a motor, but it can also be used as a generator. That is to say, when the shaft  2  is coupled to an external rotating mechanism and rotated accordingly, the magnet  324  on the assembly portion  323  is driven to rotate by the reverse coupling mode, so as to generate an alternating magnetic field encircling the iron core  311  and coil assembly  312 , and a counter electromotive force on the coil assembly  312  for electric energy output. 
         [0046]    Referring to  FIG. 1  in collaboration with  FIG. 3 , the second preferred embodiment of the gear motor of the present invention is almost the same with the first one, but the difference lies in that: the stator  31  of this preferred embodiment is provided with an iron core  311  axially set onto the casing  11  and located in the holding space  12 , and a coil assembly  312  axially wound onto the iron core  311 . The rotor  32  is provided with a pivoting portion  321  pivoted onto the shaft  2  for sleeving of the sun gear  44 , an extension  322  extended radially from the pivoting portion  321 , and a magnet  324  set laterally onto the pivoting portion  321  facing the iron core  311 , so as to form electromagnetic reaction with the iron core  311  and coil assembly  312 . 
         [0047]    In this preferred embodiment, the iron core  311  and coil assembly  312  of the stator  31  are configured axially, such that the magnet  324  can be directly mounted onto the extension  322  to generate electromagnetic reaction with the iron core  311  and coil assembly  312 . In such a case, the assembly portion  323  ( FIG. 1 ) is not required for the assembly of the magnet  324 , such that the structure of the rotor  32  is simplified for easier manufacturing. 
         [0048]    In this preferred embodiment, the coil assembly  312  is wound onto the iron core  311 , but not limited to this configuration, and the coil assembly  312  can also be routed to flexible printed circuit board. (disclosed in U.S. Pat. No. 4,455,516). 
         [0049]    Referring to  FIG. 1  in collaboration with  FIG. 4 , the third preferred embodiment of the gear motor of the present invention is almost the same with the first one, but the difference lies in that: the multi-stage planetary gear unit  6  of this preferred embodiment is provided with a first planetary gear disk  61  located in the holding space  12 , sleeved firmly onto the shaft  2  and coaxially rotated with the shaft  2 , a plurality of first planetary gears  62  (only a single one shown in  FIG. 4 ) rotarily pivoted onto the first planetary gear disk  61 , a first internal ring gear  63  set onto the second casing portion  112  of the casing  11 , located in the holding space  12  and meshed with the first planetary gear  62 , a first sun gear  64  located in the holding space  12  and meshed with the first planetary gear  62 , a second planetary gear disk  65  located in the holding space  12 , and rotarily sleeved onto the shaft  2  for sleeving of the first sun gear  64 , a plurality of second planetary gears  66  rotarily pivoted onto the second planetary gear disk  65 , a second internal ring gear  67  set onto the first casing portion  111  of the casing  11 , located in the holding space  12  and meshed with the second planetary gear  66 , and a second sun gear  68  set onto the pivoting portion  321  of the rotor  32 , coaxially rotated with the rotor  32  and meshed with the second planetary gear  66 . 
         [0050]    Furthermore, the bearing unit  5  of this preferred embodiment is provided with a sixth bearing  56  sleeved onto the shaft  2  and located between the shaft  2  and second planetary gear disk  65 , such that the second planetary gear disk  65  can be rotarily arranged on the shaft  2 . In this preferred embodiment, the sixth bearing  56  is also implemented in the form of a ball bearing. 
         [0051]    In addition, the casing  11  of the casing body  1  is constructed with a first casing portion  111 , a second casing portion  112  and a joint  113  linking the first and second casing portions  111 ,  112 . The first and second casing portions  111 ,  112  are separately used for arrangement of the first and second internal ring gears  63 ,  67 . The first bearing  51  of the bearing unit  5  is located between the shaft  2  and the first casing portion  111 , and the third bearing  53  located between the first planetary gear disk  61  and second casing portion  112 . 
         [0052]    With this construction, after the coil assembly  312  of the stator  31  is energized, the magnetic repulsion could drive the rotor  32 , which then couples with the second sun gear  68 , second planetary gear  66  and second planetary gear disk  65  for rotation. The second planetary gear disk  65  furthermore couples with the first sun gear  64 , first planetary gear  62 , first planetary gear disk  61  and the shaft  2  set on the first planetary gear disk  61  for rotation of the shaft  2 . If this preferred embodiment is implemented as a generator, it could be operated reversely, and those skilled in the art could deduce the implementation mode based on the coupling relation of parts. 
         [0053]    By integrating the multi-stage planetary gear system, this preferred embodiment allows to increase the torsion output of the shaft  2  by more flexible design of the reduction ratio. Certainly, the planetary gear system could be configured into three, four or more stages where applicable, so more multiple-stage preferred embodiments could be developed by those skilled in the art. 
         [0054]    Referring to  FIG. 4  in collaboration with  FIG. 5 , the fourth preferred embodiment of the gear motor of the present invention is almost the same with the second one, but the difference lies in that: the multi-stage planetary gear unit  6  is configured in collaboration with the stator  31 , which is provided with an iron core  311  set on the first casing portion  111  of the casing  11 , and a coil assembly  312  axially wound onto the iron core  311 ; so the magnet  324  of the rotor  32  can be directly arranged on the extension  322  to further simplify the structure of the rotor  32  as in the second preferred embodiment.