Patent Publication Number: US-2022239209-A1

Title: In-wheel working device

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application is a Division of U.S. patent application Ser. No. 16/035,705, filed on Jul. 16, 2018, which claims priority from and the benefit of Korean Patent Application No. 10-2017-0090813, filed on Jul. 18, 2017, and Korean Patent Application No. 10-2018-0069974, filed on Jun. 19, 2018, each of which is hereby incorporated by reference for all purposes as if set forth herein. 
    
    
     BACKGROUND 
     Field 
     Exemplary embodiments relate to an in-wheel working device, and more particularly, to an in-wheel working device which can secure a space for installing a gear shift in a rotor by changing a structure for measuring rotation of a motor. 
     Discussion of the Background 
     The exhaustion of fossil fuels has promoted the development of electric vehicles which drive a motor using electric energy stored in a battery, instead of vehicles using the fossil fuels such as gasoline and diesel. 
     Electric vehicles may be divided into a pure electric vehicle that drives a motor using only electric energy stored in a rechargeable battery, a solar cell vehicle that drives a motor using a photoelectric cell, a fuel cell vehicle that drives a motor using a fuel cell based on hydrogen fuel, and a hybrid vehicle that uses an engine and motor together by driving the engine using fossil fuel and driving the motor using electricity. 
     In general, an in-wheel working device is a technique used for a vehicle, such as an electric vehicle, which uses electricity as a power source. Unlike a system that rotationally drives wheels using power transferred through an engine, transmission, and drive shaft of a gasoline or diesel vehicle, the in-wheel working device directly transfers power to the wheels using motors arranged in left and right drive wheels or four left/right and front/rear drive wheels. 
     Since a resolver for measuring rotation of the motor in the conventional in-wheel working device is installed on a rotating shaft of the motor, the size of the in-wheel working device is increased, which makes it difficult to additionally install a gear shift in a rotor. In this case, the power of the vehicle may be reduced. Therefore, there is a demand for a device capable of solving the problem. 
     The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and, therefore, it may contain information that does not constitute prior art. 
     SUMMARY 
     Exemplary embodiments of the invention are directed to an in-wheel working device which can secure a space for installing a gear shift in a rotor by changing a structure for measuring rotation of a motor, thereby improving mounting compatibility and power. 
     An exemplary embodiment of the invention provides an in-wheel working device including: a stator fixed to the inside of a housing; a rotor rotatably installed in the stator; a rotating part rotatably installed in the housing, and rotated with the rotor; a resolver fixing part fixed to the inside of the housing; and a resolver moving part. The resolver moving part includes a resolver rotor positioned outside the resolver fixing part facing the resolver fixing part, and a cover part fixed to the rotating part and covering the resolver rotor. 
     The cover part may be injection-molded in a shape to cover the resolver rotor. 
     The rotating part may include a mounting frame installed in a shape to cover the rotor; and a motor shaft connected to the mounting frame, having a hollow portion formed therein, and rotatably installed in the housing. 
     The cover part may have a larger inner diameter than the outer diameter of the resolver fixing part, and fixed to the mounting frame. 
     The in-wheel working device may further include: a gear shift part configured to shift gears using power received from the motor shaft; and a drive shaft formed in a shaft shape passing through the inside of the motor shaft, and rotated by power received from the gear shift part. 
     The cover part may include a first cover installed in a shape to cover one side of the resolver rotor; and a second cover installed in a shape to cover the other side of the resolver rotor. 
     The first cover may include a first base forming a plane in a circular arc shape at a position facing the one side of the resolver rotor; a first inner member extended from the inner circumference of the first base toward the second cover; and a first outer member extended from the outer circumference of the first base toward the second cover. 
     The second cover may include a second base forming a plane in a circular arc shape at a position facing the other side of the resolver rotor; a second inner member extended from the inner circumference of the second base toward the first cover; and a second outer member extended from the outer circumference of the second base toward the first cover. 
     Another exemplary embodiment of the invention provides an in-wheel working device including: a stator fixed to the inside of a housing; a rotor rotatably installed in the stator; a rotating part rotatably installed in the housing, and rotated with the rotor; a resolver fixing part fixed to the inside of the housing; and a resolver rotor positioned outside the resolver fixing part facing the resolver fixing part. The resolver rotor is fixed to the rotating part, rotated with the rotating part, and implemented with a single member. 
     The resolver rotor may include a rotor body forming a plane in a belt shape along a circular arc shape; and an inner groove forming a polygonal groove in the rotor body. 
     The rotating part may include a mounting frame installed in a shape to cover the rotor; and a motor shaft connected to the mounting frame, having a hollow portion formed therein, and rotatably installed in the housing. 
     The rotor body may be fixed to the mounting frame by a fastening member. 
     The rotor body may have a plurality of mounting grooves formed along the outer circumference thereof, and the mounting grooves directly mounted on the mounting frame. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention, and together with the description serve to explain the principles of the invention. 
         FIG. 1  schematically illustrates the structure of an in-wheel working device in accordance with a first embodiment of the present invention. 
         FIG. 2  illustrates an installation state of a resolver moving part and a resolver fixing part in accordance with the first embodiment of the present invention. 
         FIG. 3  illustrates the resolver moving part and the resolver fixing part in accordance with the first embodiment of the present invention. 
         FIG. 4  schematically illustrates the structure of an in-wheel working device in accordance with a second embodiment of the present invention. 
         FIG. 5  is an exploded perspective view of a resolver moving part in accordance with the second embodiment of the present invention. 
         FIG. 6  is an assembled perspective view of the resolver moving part in accordance with the second embodiment of the present invention. 
         FIG. 7  is a perspective view illustrating that a resolver rotor in accordance with the present embodiment has fastening holes formed therein. 
         FIG. 8  is a perspective view illustrating that a resolver rotor in accordance with another embodiment of the present invention has mounting grooves. 
     
    
    
     DETAILED DESCRIPTION 
     The invention is described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the exemplary embodiments set forth herein. Rather, these exemplary embodiments are provided so that this disclosure is thorough, and will fully convey the scope of the invention to those skilled in the art. In the drawings, the size and relative sizes of layers and regions may be exaggerated for clarity. Like reference numerals in the drawings denote like elements. 
     It will be understood that for purposes of this disclosure, “at least one of X, Y, and Z” can be construed as X only, Y only, Z only, or any combination of two or more items X, Y, and Z (e.g., XYZ, XYY, YZ, ZZ). Unless particularly described to the contrary, the term “comprise”, “configure”, “have”, or the like, which are described herein, will be understood to imply the inclusion of the stated components, and therefore should be construed as including other components, and not the exclusion of any other elements. 
     Hereafter, an in-wheel working device in accordance with an exemplary embodiment of the invention will be described in detail with reference to the accompanying drawings. It should be noted that the drawings are not to precise scale and may be exaggerated in thickness of lines or sizes of components for descriptive convenience and clarity only. 
     Furthermore, the terms as used herein are defined by taking functions of the invention into account and can be changed according to the custom or intention of users or operators. Therefore, definition of the terms should be made according to the overall disclosures set forth herein. 
       FIG. 1  schematically illustrates the structure of an in-wheel working device in accordance with a first embodiment of the present invention,  FIG. 2  illustrates an installation state of a resolver moving part and a resolver fixing part in accordance with the first embodiment of the present invention, and  FIG. 3  illustrates the resolver moving part and the resolver fixing part in accordance with the first embodiment of the present invention. 
     As illustrated in  FIGS. 1 to 3 , the in-wheel working device  1  in accordance with the embodiment of the present invention may include a stator  20  fixed to the inside of a housing  10 , a rotor  30  rotatably installed in the stator  20 , a rotating part  40  rotatably installed in the housing  10  and rotated with the rotor  30 , a resolver moving part  50  fixed to the rotating part  40  and rotated with the rotating part  40 , and a resolver fixing part  90  fixed to the inside of the housing  10  facing the resolver moving part  50 . 
     The housing  10  forming the exterior of the in-wheel working device  1  may be fixed to a vehicle body, and the stator  20 , the rotor  30 , the rotating part  40 , the resolver moving part  50 , the resolver fixing part  90 , a gear shift part  100 , a drive shaft  110  and a hub part  120  may be installed in the housing  10 . 
     The stator  20  may be formed in a ring shape, and fixed to the inside of the housing  10 . The stator  20  may have coil members  22  installed at the top and bottom thereof, respectively, and the rotations of the stator  20  and the coil member  22  may be constrained. 
     The rotor  30  may be rotatably installed in the stator  20 , and rotated according to flux changes of the stator  20  and the coil member  22 . The rotor  30  may be formed in a ring shape, and have a magnetic force. Since the detailed configurations and operations of the stator  20  and the rotor  30  are publicly known, the detailed descriptions thereof are omitted herein. 
     The rotating part  40  may be formed in various shapes, as long as the rotating part  40  can be rotatably installed in the housing  10  and rotated with the rotor  30 . The rotating part  40  in accordance with the present embodiment may include a mounting frame  42  and a motor shaft  44 . The mounting frame  42  may be formed in a plate shape which is brought in contact with one side surface and the top and bottom surfaces of the rotor  30  with a rectangular cross-section, and connected to the rotor  30  so as to rotate with the rotor  30 . The mounting frame  42  may have a protrusion formed at the top thereof, and the resolver moving part  50  may be fixed to the protrusion. Therefore, the rotating part  40 , the rotor  30  and the resolver moving part  50  may be rotated together. 
     The motor shaft  44  may be connected to the mounting frame  42  and rotated with the mounting frame  42 . Furthermore, the motor shaft  44  may be rotatably installed in the housing  10 , and have a hollow portion formed therein. The motor shaft  44  may be extended in the top-to-bottom direction, the gear shift part  100  may be installed at one side of the motor shaft  44 , and the hub part  120  may be installed at the other side of the motor shaft  44 . 
     The resolver moving part  50  may be fixed to the rotating part  40 , and rotated with the rotating part  40 . The resolver moving part  50  in accordance with the present embodiment may include a cover part  52  and a resolver rotor  51 . 
     The cover part  52  may be formed through injection molding, fixed to the mounting frame  42 , and have a larger inner diameter than the outer diameter of the resolver fixing part  90 . The resolver rotor  51  may be fixed to the cover part  52 , and positioned outside the resolver fixing part  90 . Since the cover part  52  formed of synthetic resin is injection-molded in a shape to cover the resolver rotor  51 , the resolver rotor  51  and the cover part  52  may be coupled as one body. Furthermore, since the cover part  52  is fixed to the outside of the mounting frame  42 , the resolver moving part  50  may be rotated with the rotating part  40 . 
     The resolver fixing part  90  may be fixed to the inside of the housing  10  facing the resolver moving part  50 . Each of the resolver rotor  51  and the resolver fixing part  90  may have a two-phase winding, and detect the angular velocity and angular position of the rotating part  40  through a change of an output voltage value. For example, the coil of the resolver fixing part  90  may be wound in such a manner that flux distribution becomes a sine wave with respect to an angle. When the rotor  30  is rotated after an excitation voltage is applied to the primary coil corresponding to an input side, a voltage may be generated at the secondary coil corresponding to an output side while a magnetic coupling coefficient is changed. The coil of the resolver fixing part  90  may be wound in such a manner that the voltage is changed to the sine and cosine of the rotation angle of the rotor  30 . The amplitude ratio of the sine output to the cosine output may be determined in order to recognize the rotation angle and position of the rotor  30 . In addition, various resolver measurement techniques can be applied in order to measure the angular position and angle of the rotor  30 . 
     The resolver fixing part  90  may be formed in a ring shape and fixed to the inside of the housing  10 , the inside of the resolver rotor  51  positioned outside the resolver fixing part  90  may form a polygonal groove, and the outside of the resolver rotor  51  may form a circular curved surface. The cover part  52  may have a larger outer diameter than the outer diameter of the resolver rotor  51 , and injection-molded with the resolver rotor  51 . 
     In order to reduce noise caused by the motor including the stator  20  and the rotor  30 , the cover part  52  may be mounted outside the resolver rotor  51 . Since the resolver moving part  50  is installed at the top of the rotor  30  or adjacent to the coil member  22 , noise is highly likely to be generated by an electromagnetic force generated by the rotor  30  and the stator  20 . Thus, the cover part  52  may be installed to cover the resolver rotor  51 , such that a space for isolating the resolver rotor  51  from the rotor  30  can be secured while the electromagnetic force of the stator  20  and the rotor  30  is reduced. Therefore, noise can be reduced. 
     The in-wheel working device  1  in accordance with the embodiment of the present invention may further include the gear shift part  100 , the drive shaft  110  and the hub part  120 . The gear shift part  100  may include various types of gear shift devices, as long as the gear shift part  100  can shift gears using power received from the motor shaft  44 . The gear shift part  100  in accordance with the embodiment of the present invention may include a sun gear  102 , a planetary gear  104 , a carrier  106  and a ring gear  108 . 
     The sun gear  102  may be connected to the top of the motor shaft  44 , and have gear teeth formed outside a pipe-shaped body thereof. Therefore, the sun gear  102  may be rotated with the motor shaft  44 . The planetary gear  104  may be installed outside the sun gear  102 , and the carrier  106  may rotatably support the planetary gear  104 . The ring gear  108  positioned outside the carrier  106  may maintain a fixed state. 
     Since the carrier  106  is connected to the drive shaft  110 , power reduced through the carrier  106  may be outputted through the drive shaft  110 . 
     The drive shaft  110  may be formed in a shaft shape which passes through the inside of the motor shaft  44 , and rotated by power received from the gear shift part  100 . The top of the drive shaft  110  extended in the top-to-bottom direction may be connected to the carrier  106 , and the bottom of the drive shaft  110  may be connected to a hub inner race  122  of the hub part  120  so as to receive rotation power. 
     The hub part  120  may include the hub inner race  122 , a hub outer race  124  and a hub bearing  126 . The hub inner race  122  may be spline-coupled to the drive shaft  110 , and rotated with the drive shaft  110 , the hub outer race  124  may be positioned outside the hub inner race  122 , and the hub bearing  126  may be positioned between the hub inner race  122  and the hub outer race  124 . The wheel of the vehicle may be rotated by the rotation of the hub inner race  122 . 
     Hereafter, the operation state of the in-wheel working device  1  in accordance with the embodiment of the present invention will be described in detail with reference to the accompanying drawings. 
     The mounting frame  42  and the motor shaft  44  which constitute the rotating part  40  may be rotated by the rotation of the rotor  30 . At this time, the cover part  52  and the resolver rotor  51  of the resolver moving part  50  fixed to the mounting frame  42  may also be rotated. Therefore, the resolver fixing part  90  may measure the angular velocity and angular position of the resolver moving part  50 , in order to recognize the angular velocity and angular position of the rotor  30 . Since the resolver moving part  50  and the resolver fixing part  90  which constitute the resolver are positioned at the top of the rotor  30 , the gear shift part  100  can be installed at the top of the motor shaft  44  while an increase of the size is minimized. 
     The sun gear  102  may be rotated by the rotation of the motor shaft  44 , and the carrier  106  supporting the planetary gear  104  may be rotated while the velocity thereof is reduced. The drive shaft  110  connected to the carrier  106  may transfer power to the spline-coupled hub inner race  122 , and the wheel of the vehicle may be rotated by the rotation of the hub inner race  122 . 
     In accordance with the embodiment of the present invention, since the resolver moving part  50  and the resolver fixing part  90  for measuring the rotation of the rotor  30  are installed in the stator  20 , the installation space of the gear shift part  100  for changing the output of the rotating part  40  can be secured, which makes it possible to improve the power of the vehicle. 
       FIG. 4  schematically illustrates the structure of an in-wheel working device in accordance with a second embodiment of the present invention,  FIG. 5  is an exploded perspective view of a resolver moving part in accordance with the second embodiment of the present invention, and  FIG. 6  is an assembled perspective view of the resolver moving part in accordance with the second embodiment of the present invention. 
     As illustrated in  FIGS. 4 to 6 , the in-wheel working device  1  in accordance with the second embodiment of the present invention may include a stator  20  fixed to the inside of a housing  10 , a rotor  30  rotatably installed in the stator  20 , a rotating part  40  rotatably installed in the housing  10  and rotated with the rotor  30 , a resolver moving part  50  fixed to the rotating part  40 , rotated with the rotating part  40 , and implemented by a plurality of members, and a resolver fixing part  90  fixed to the inside of the housing  10  facing the resolver moving part  50 . 
     The housing  10  forming the exterior of the in-wheel working device  1  may be fixed to the vehicle body, and the stator  20 , the rotor  30 , the rotating part  40 , the resolver moving part  50 , the resolver fixing part  90 , a gear shift part  100 , a drive shaft  110  and a hub part  120  may be installed in the housing  10 . 
     The stator  20  may be formed in a ring shape, and fixed in the housing  10 . The stator  20  may have coil members  22  installed at the top and bottom thereof, and the stator  20  and the coil members  22  may be constrained from rotating. 
     The rotor  30  may be rotatably installed in the stator  20 , and rotated according to flux changes of the stator  20  and the coil member  22 . The rotor  30  may be formed in a ring shape, and have a magnetic force. Since the detailed configurations and operations of the stator  20  and the rotor  30  are publicly known, the detailed descriptions thereof are omitted herein. 
     The rotating part  40  may be formed in various shapes, as long as the rotating part  40  can be rotatably installed in the housing  10  and rotated with the rotor  30 . The rotating part  40  in accordance with the second embodiment may include a mounting frame  42  and a motor shaft  44 . The mounting frame  42  may be formed in a plate shape which is brought in contact with one side surface and the top and bottom surfaces of the rotor  30 , and the rotor  30  may be connected to the mounting frame  42  and rotated with the mounting frame  42 . 
     The mounting frame  42  may have a protrusion formed at the top thereof, and the resolver moving part  50  may be fixed to the protrusion. Therefore, the rotating part  40 , the rotor  30  and the resolver moving part  50  may be rotated together. 
     The motor shaft  44  may be connected to the mounting frame  42  and rotated with the mounting frame  42 . Furthermore, the motor shaft  44  may be rotatably installed in the housing  10 , and have a hollow portion formed therein. The motor shaft  44  may be extended in the top-to-bottom direction, the gear shift part  100  may be installed at one side of the motor shaft  44 , and the hub part  120  may be installed at the other side of the motor shaft  44 . 
     The resolver moving part  50  may be fixed to the rotating part  40 , and rotated with the rotating part  40 . The resolver moving part  50  in accordance with the second embodiment may include a resolver rotor  51  and a cover part  52 . The cover part  52  may include a first cover  53  and a second cover  56 . 
     The resolver rotor  51  may be formed in a ring shape and positioned outside the resolver fixing part  90 , the inside of the resolver rotor  51  may form a polygonal groove, and the outside of the resolver rotor  51  may form a circular curved surface. 
     The first cover  53  may be installed in a shape to cover one side of the resolver rotor  51 , and the second cover  56  may be installed in a shape to cover the other side of the resolver rotor  51 . The first and second covers  53  and  56  may be injection-molded separately from the resolver rotor  51 , and then coupled to the resolver rotor  51  so as to form an assembly. The resolver rotor  51  may be used in common, and the first and second covers  53  and  56  may be manufactured in a package shape and coupled to the resolver rotor  51 , which makes it possible to remove a problem that the manufacturing cost is increased by a model change. 
     The first and second covers  53  and  56  may be formed through injection molding, fixed to the mounting frame  42 , and have a larger inner diameter than the outer diameter of the resolver fixing part  90 . The resolver rotor  51  may be positioned between the first and second covers  53  and  56 . The first and second covers  53  and  56  may be formed of synthetic resin, injection-molded separately from the resolver rotor  51 , and installed in a shape to cover the resolver rotor  51 . Furthermore, since the first and second covers  53  and  56  are fixed to the outside of the mounting frame  42 , the resolver moving part  50  may be rotated with the rotating part  40 . 
     The first cover  53  in accordance with the second embodiment may include a first base  54 , a plurality of first inner members  55 A and a first outer member  55 B. The first base  54  may form a plane in a circular arc shape at a position facing the one side of the resolver rotor  51 . 
     The first inner members  55 A may be extended from the inner circumference of the first base  54  toward the second cover  56 . The first inner members  55 A may be installed along the inner circumference of the first base  54  so as to be spaced at preset intervals. 
     The first outer member  55 B may be extended from the outer circumference of the first base  54  toward the second cover  56 . Between the first inner members  55 A and the first outer member  55 B, a groove for seating the resolver rotor  51  may be formed. The first outer member  55 B may be extended in a ring shape while having a level difference from the first base  54 . 
     The second cover  56  in accordance with the second embodiment may include a second base  57 , a plurality of second inner members  58 A and a second outer member  58 B. The second base  57  may form a plane in a circular arc shape at a position facing the other side of the resolver rotor  51 . 
     The second inner members  58 A may be extended from the inner circumference of the second base  57  toward the first cover  53 . The second inner members  58 A may be installed along the inner circumference of the second base  57  so as to be spaced at preset intervals. 
     The second outer member  58 B may be extended from the outer circumference of the second base  57  toward the first cover  53 . Between the second inner members  58 A and the second outer member  58 B, a groove for seating the resolver rotor  51  may be formed. The second outer member  58 B may be extended in a ring shape while having a level difference from the second base  57 . 
     With the resolver rotor  51  positioned between the first and second covers  53  and  56 , the first inner member  54  may be brought in contact with the second inner member  58 A and constrained from moving, and the first outer member  55 B may also be brought in contact with the second outer member  58 B and constrained from moving. The first and second covers  53  and  56  may be fixed through a bolt or adhesive. Alternatively, the first and second covers  53  and  56  may be fixed to each other through various coupling methods such as laser welding and thermal welding. 
     In order to reduce noise caused by the motor including the stator  20  and the rotor  30 , the first and second covers  53  and  56  may be mounted on the outside of the resolver rotor  51 . Since the resolver moving part  50  is installed at the top of the rotor  30  or adjacent to the coil member  22 , noise is likely to be caused by an electromagnetic force generated by the rotor  30  and the stator  20 . Therefore, the first and second covers  53  and  56  may be installed to cover the resolver rotor  51 , such that a space for isolating the resolver rotor  51  from the rotor  30  can be secured while reducing the electromagnetic force of the stator  20  and the rotor  30 , transferred to the resolver rotor  51 . Thus, noise can be reduced. 
     The resolver fixing part  90  may be fixed to the inside of the housing  10  facing the resolver moving part  50 . Each of the resolver rotor  51  and the resolver fixing part  90  may have a two-phase winding, and detect an angular velocity and angular position of the rotating part  40  through a change of an output voltage. For example, the coil of the resolver fixing part  90  may be wound in such a manner that flux distribution becomes a sine wave with respect to an angle. When the rotor  30  is rotated after an excitation voltage is applied to the primary coil corresponding to an input side, a voltage may be generated at the secondary coil corresponding to an output side while a magnetic coupling coefficient is changed. The coil of the resolver fixing part  90  may be wound in such a manner that the voltage is changed to the sine and cosine of the rotation angle of the rotor  30 . The amplitude ratio of the sine output to the cosine output may be determined in order to recognize the rotation angle and position of the rotor  30 . In addition, various resolver measurement techniques can be applied in order to measure the rotation position and angle of the rotor  30 . Since the resolver fixing part  90  in accordance with the second embodiment is formed in a ring shape and fixed to the inside of the housing  10 , the rotation of the resolver fixing part  90  may be constrained. 
     The in-wheel working device  1  in accordance with the second embodiment of the present invention may further include the gear shift part  100 , the drive shaft  110  and the hub part  120 . The gear shift part  100  may include various types of gear shift devices, as long as the gear shift part  100  can shift gears using power received from the motor shaft  44 . The gear shift part  100  in accordance with the second embodiment may include a sun gear  102 , a planetary gear  104 , a carrier  106  and a ring gear  108 . 
     The sun gear  102  may be connected to the top of the motor shaft  44 , and have gear teeth formed on the outside of the pipe-shaped body thereof. Therefore, the sun gear  102  may be rotated with the motor shaft  44 . The planetary gear  104  may be installed outside the sun gear  102 , and the carrier  106  may rotatably support the planetary gear  104 . The ring gear  108  positioned outside the carrier  106  may maintain a fixed state. 
     Since the carrier  106  is connected to the drive shaft  110 , power reduced through the carrier  106  may be outputted through the drive shaft  110 . 
     The drive shaft  110  may be formed in a shaft shape which passes through the inside of the motor shaft  44 , and rotated by power received from the gear shift part  100 . The top of the drive shaft  110  extended in the top-to-bottom direction may be connected to the carrier  106 , and the bottom of the drive shaft  110  may be connected to a hub inner race  122  of the hub part  120  so as to receive rotation power. 
     The hub part  120  may include the hub inner race  122 , a hub outer race  124  and a hub bearing  126 . The hub inner race  122  may be spline-coupled to the drive shaft  110  and rotated with the drive shaft  110 , the hub outer race  124  may be positioned outside the hub inner race  122 , and the hub bearing  126  may be positioned between the hub inner race  122  ad the hub outer race  124 . The wheels of the vehicle may be rotated by the rotation of the hub inner race  122 . 
     Hereafter, the operation state of the in-wheel working device  1  in accordance with the second embodiment of the present invention will be described in detail with reference to the accompanying drawings. 
     The mounting frame  42  and the motor shaft  44  which constitute the rotating part  40  may be rotated by the rotation of the rotor  30 . At this time, the first and second covers  53  and  56  and the resolver rotor  2  of the resolver moving part  50  fixed to the mounting frame  42  may also be rotated. Therefore, the resolver fixing part  90  may measure the angular velocity and angular position of the resolver moving part  50 , in order to recognize the angular velocity and angular position of the rotor  30 . Since the resolver moving part  50  and the resolver fixing part  90  which constitute the resolver are positioned at the top of the rotor  30 , the gear shift part  100  may be installed at the top of the motor shaft  44  while an increase of the size is minimized. 
     The sun gear  102  may be rotated by the rotation of the motor shaft  44 , and the carrier  106  supporting the planetary gear  104  may be rotated while the velocity thereof is reduced. The drive shaft  110  connected to the carrier  106  may transfer power to the spline-coupled hub inner race  122 , and the wheels of the vehicle may be rotated by the rotation of the hub inner race  122 . 
     Even when the model is changed, the resolver rotor  51  can be used in common, and only the first and second covers  53  and  56  may be separately manufactured, which makes it possible to save the manufacturing cost and distribution cost. Furthermore, only the first and second covers  53  and  56  may be separately manufactured and applied to a package, and various assembly structures can be applied depending to the shapes of the first and second covers  53  and  56 . 
     Hereafter, an in-wheel working device  1  in accordance with another embodiment of the present invention will be described with reference to the drawings. 
     For convenience of description, components which are configured and operated in the same manner as those of the second embodiment are represented by like reference numerals, and the detailed descriptions thereof are omitted herein. 
       FIG. 7  is a perspective view illustrating that a resolver rotor in accordance with the present embodiment has fastening holes formed therein. 
     As illustrated in  FIGS. 4 to 7 , the in-wheel working device  1  in accordance with the present embodiment may include a stator  20  fixed to the inside of a housing  10 , a rotor  30  rotatably installed in the stator  20 , a rotating part  40  rotatably installed in the housing  10  and rotated with the rotor  30 , a resolver rotor  51  fixed to the rotating part  40 , rotated with the rotating part  40 , and implemented with a single member, and a resolver fixing part  90  fixed to the inside of the housing  10  facing the resolver rotor  51 . 
     The resolver rotor  51  in accordance with the present embodiment is positioned outside the resolver fixing part  90  and fixed to the rotating part  40 . The resolver rotor  51  in accordance with the present embodiment may include a rotor body  511 , an inner groove  512  and a plurality of fastening holes  513 . 
     The rotor body  511  may form a plane in a belt shape along a circular arc shape. The outside of the rotor body  511  may form a circular curved surface. The inner groove  512  may form a polygonal groove in the rotor body  511 . 
     The plurality of fastening holes  513  may be used to install a fastening member  514  in the rotor body  511 . The fastening member  514  may be a bolt. The plurality of fastening holes  513  may be formed along the rotor body  511 , and the fastening member  514  may be fixed to the mounting frame  42  through the fastening holes  513  formed in the rotor body  511 . Therefore, the resolver rotor  51  may be directly mounted on the rotating part  40  without a separate cover part, and rotated with the rotating part  40 . 
     When the resolver rotor  51  and the resolver fixing part  90  are spaced at a sufficient distance from the stator  20  to generate electromagnetic waves, the resolver rotor  51  may be directly mounted on the rotating part  40  without a separate cover part. When the resolver rotor  51  and the resolver fixing part  90  are installed close to the drive shaft  110  serving as a motor rotating shaft, the influence of electromagnetic noise may be limited. Therefore, the resolver rotor  51  may be directly fastened to the rotating part  40  or the drive shaft  110 . 
       FIG. 8  is a perspective view illustrating that a resolver rotor in accordance with another embodiment of the present invention has mounting grooves. 
     As illustrated in  FIGS. 4 and 8 , the resolver rotor  51  in accordance with the present embodiment may include a rotor body  516 , an inner groove  517  and a plurality of mounting grooves  518 . 
     The rotor body  516  may form a plane in a belt shape along a circular arc shape. The outside of the rotor body  516  may form a circular curved surface. The inner groove  517  may form a polygonal groove in the rotor body  516 . 
     The plurality of mounting grooves  518  may be formed along the outer circumference of the rotor body  516 . The plurality of mounting grooves  518  may be installed at preset intervals on the outer circumference of the rotor body  516 . Therefore, separate protrusions  421  formed on the mounting frame  42  of the rotating part  40  may be inserted into the mounting grooves  518 . Thus, the resolver rotor  51  may be directly mounted on the rotating part  40  without a separate cover part, and rotated with the rotating part  40 . 
     As described above, the first and second covers  53  and  56  may be injection-molded as separate products and coupled to the resolver rotor  51 . Thus, since the resolver rotor  51  can be used in common, the manufacturing cost can be reduced. 
     Furthermore, since the resolver rotor  51  is directly fixed to the rotating part  40  without a separate cover part, the space can be utilized more efficiently. 
     Furthermore, since the rotor  51  or the resolver moving part  60  and the resolver fixing part  90  for measuring the rotation of the rotor  30  are installed in the stator  20 , the installation space of the gear shift part  100  for changing the output of the rotating part  40  can be secured, which makes it possible to improve the power of the vehicle. 
     Although exemplary embodiments of the invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as defined in the accompanying claims.