Patent Publication Number: US-2016241101-A1

Title: Motor and robot

Description:
BACKGROUND 
     1. Technical Field 
     The present invention relates to a motor and a robot. 
     2. Related Art 
     When a stator of an electromotor (motor) is configured, a winding is wound around a bobbin, and then, a predetermined number of the bobbins are mounted on a laminated core. Finally, the laminated core on which the bobbins are mounted is inserted in an injection mold, and a sheath protection insulating layer is resin-molded under predetermined pressure and heat. In this process, the winding positioned at the winding outermost surface part of the bobbin may be peeled off from the surface by the pressure and heat, and the winding may protrude from a space between the adjacent bobbins by the pressure and may approach the laminated core. This may cause insulation failure. 
     On this issue, a manufacturing method of a stator assembly is disclosed in which a winding is coiled around a resin bobbin mounted on a salient pole of a laminated core, and these are coated with an sheath protection insulating layer (see, for example, Patent Literature 1 (JP-A-2005-143206)). A technique is disclosed in which a gap between the stator assembly and a cavity for injection molding of the sheath protection insulation layer is regulated in order to reduce the deformation of the bobbin in the manufacturing process of coating the stator assembly. 
     However, there is also a problem of movement of the winding in addition to the deformation of the bobbin by the injection pressure disclosed in Patent Literature 1. 
     SUMMARY 
     An advantage of some aspects of the invention is to solve at least part of the problems described above and the invention can be implemented as following forms or application examples. 
     Application Example 1 
     A motor according to this application example includes a stator core, plural bobbins mounted on the stator core and provided with flange parts, and a winding wound around each of the bobbins, in which a space of a gap between the plural flange parts adjacent to each other is smaller than a diameter of the winding. 
     According to this application example, both ends of the flange part of the bobbin are extended, and the space of the gap between the adjacent flange parts is made smaller than at least the single wire diameter of the winding. Hereby, the protrusion of the winding from the space of the gap between the adjacent flange parts can be prevented. Accordingly, the motor in which insulation failure is prevented can be provided. 
     Application Example 2 
     In the motor according to the application example, it is preferable that the space of the gap is more than 0.2 mm and smaller than 0.3 mm. 
     According to this application example, the protrusion of the winding from the space of the gap between the adjacent flange parts can be prevented. 
     Application Example 3 
     In the motor according to the application example, it is preferable that the gap between the plural flange parts adjacent to each other has a shape bent with respect to a radial direction of the stator core. 
     According to this application example, the protrusion of the winding from the space of the gap between the adjacent flange parts can be prevented. 
     Application Example 4 
     In the motor according to the application example, it is preferable that the gap between the plural flange parts adjacent to each other has a shape widening in a radial direction of the stator core. 
     According to this application example, the protrusion of the winding from the space of the gap between the adjacent flange parts can be prevented. Incidentally, the gap is desirably formed such that the space widens toward the outside in the radial direction of the stator core. 
     Application Example 5 
     A robot according to this application example includes the motor described in any one of the application examples set forth above. 
     According to this application example, the highly reliable robot can be provided. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements. 
         FIG. 1  is a sectional view showing a motor according to a first embodiment. 
         FIGS. 2A and 2B  are views showing a structure of a stator according to the first embodiment, in which  FIG. 2A  shows fitting of bobbins to teeth, and  FIG. 2B  shows fitting of a yoke. 
         FIG. 3  is a view showing the shape of a gap between plural flange parts adjacent to each other according to the first embodiment. 
         FIG. 4  is a view showing the shape of a gap between plural flange parts adjacent to each other according to a second embodiment. 
         FIGS. 5A and 5B  are views showing the shape of a gap between plural flange parts adjacent to each other according to modifications, in which  FIG. 5A  shows a shape obliquely crossing the radial direction of a stator core, and  FIG. 5B  shows a shape widening in the radial direction of the stator core. 
         FIG. 6  is a perspective view showing a robot to which a motor according to the embodiment is applied. 
         FIG. 7  is a perspective view showing a robot to which a motor according to the embodiment is applied. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Hereinafter, embodiments of a motor embodying the invention will be described with reference to the drawings. Incidentally, the drawings are appropriately enlarged or reduced so that portions to be described can be recognized. 
     First Embodiment 
     Motor 
       FIG. 1  is a sectional view showing a motor according to an embodiment. 
     As shown in  FIG. 1 , the motor  1  according to the embodiment includes a housing  10 , a rotation shaft  12 , a stator and a rotor  16 . Incidentally, the motor  1  is not particularly limited, and may be, for example, a servo motor, a stepping motor or the like. 
     Bearings  18  and  20  are provided on an upper wall and a bottom wall of the housing  10 . The rotation shaft  12  is rotatably supported on the bearings  18  and  20 . The rotor  16  is fixed to the rotation shaft  12  in the housing  10 . The rotor  16  is cylindrical and includes a core  22  made of a soft magnetic material such as iron and a permanent magnet  24  provided on the outer periphery of the core  22 . Besides, the stator  14  is disposed around the rotor  16 . The material of the housing  10  is, for example, a conductive metal. The permanent magnet  24  has a circular cylindrical shape. Besides, the permanent magnet  24  has a multi-polar structure in which plural magnetic poles are formed in the circumferential direction thereof. 
       FIGS. 2A and 2B  are views showing a structure of the stator  14  according to the embodiment.  FIG. 2A  shows fitting of bobbins  30  to teeth  26 , and  FIG. 2B  shows fitting of a yoke  46 .  FIG. 3  is a view showing a shape of a gap  5  between plural second flange parts  38  adjacent to each other according to the embodiment. Incidentally,  FIG. 3  is an enlarged view of a region indicated by a circle in  FIG. 2B . Besides,  FIG. 3  additionally shows the yoke  46  and a mold part  60 . 
     The stator  14  includes a stator core  28  having plural teeth  26  arranged in a circumferential direction relative to an axial line, the tubular bobbins  30  assembled to the outside of the teeth  26  in a radial direction, a winding  40  wound around the teeth  26  through the bobbin  30 , a pair of pins  34  around which each of ends of the winding  40  is twined, and the mold part  60  covering the bobbins  30 , the winding  40  and the pins  34 . The stator core  28  includes an annular part  25  formed into an annular shape, and the plural teeth  26  extending in the radial direction from the annular part  25 . 
     The bobbin  30  includes a tubular core part  36  covering the outer peripheral surface of the teeth  26 , and first and second flange parts  37  and  38  extending in the radial direction on both ends of the core part  36 . The bobbin  30  is provided outside the teeth  26 , and includes the tubular core part  36  around which the winding  40  is wound, the first flange part  37  extending to the inside in the radial direction from the core part  36 , and the second flange part  38  extending to the outside in the radial direction from the core part  36 . The pins  34  are fixed to the second flange part  38 . The second flange part  38  of the bobbin  30  is provided to be continuous with the core part  36 . 
     A space of the gap  5  between the plural second flange parts  38  adjacent to each other according to the embodiment is smaller than a diameter of the winding  40 . 
     The space of the gap  5  is preferably larger than 0.2 mm and smaller than 0.3 mm. For example, when the diameter of the winding  40  is 0.286 mm, the gap  5  is the space smaller than 0.286 mm. According to this, the protrusion of the winding  40  from the space of the gap  5  between the adjacent second flange parts  38  and  38  can be prevented. Besides, when the diameter of the winding  40  is 0.416 mm, the gap  5  is the space smaller than 0.416 mm. 
     However, when the space of the gap  5  is smaller than 0.2 mm, the stator core  28  and the bobbin  30  can not be assembled. Thus, the space of the gap  5  is required to be 0.2 mm or more. 
     The bobbin  30  can be formed by using a material having insulation, such as an insulating synthetic resin. The bobbin  30  is molded by injection molding of PPS resin or the like. Incidentally, in addition to the PPS resin, Noryl, PA (polyamide), PBTP (polybutylene terephthalate), PETP (polyethylene terephthalate) or PC (polycarbonate) may be used as the material of the bobbin  30 . 
     Both a thermoplastic resin and a thermosetting resin, such as BMC (unsaturated polyester) resin, PPS (polyphenylene sulfide) resin, phenol resin, melamine resin, urea resin and LCP (liquid crystal polymer) resin, can be used as the material of the mold part  60 . A resin having high heat resistance and filled with heat-conductive filler is preferably used. As the filler, a metal material can also be used in addition to a ceramic such as alumina or silica. 
     According to the embodiment, both ends of the second flange parts  38  and  38  of the bobbins  30  are extended, and the space of the gap  5  between the adjacent second flange parts  38  and  38  is made smaller than, at least, the diameter of the winding  40 . Hereby, the protrusion of the winding  40  from the space of the gap  5  between the adjacent second flange parts  38  and  38  can be prevented. Accordingly, the motor  1  in which insulation failure is prevented can be provided. 
     Second Embodiment 
       FIG. 4  is a view showing a shape of a gap  5  between plural second flange parts  38  adjacent to each other according to the embodiment. Incidentally,  FIG. 4  shows the adjacent second flange parts  38  of bobbins  30 , and a winding  40  wound around the bobbin  30  and the like are omitted. 
     The gap  5  between the plural second flange parts  38  adjacent to each other has the shape bent with respect to a radial direction of a stator core  28 . According to this, the protrusion of the winding  40  from the space of the gap  5  between the adjacent second flange parts  38  and  38  can be prevented. 
     For example, as shown in  FIG. 4 , in a state where the bobbins  30  are inserted to plural teeth  26 , an overlap part  4  is formed between the adjacent bobbins  30  and  30 , in which a first projection part  61  and a second projection part  64  adjacent to each other overlap each other in the radial direction of the stator core  28 . 
     That is, the first projection part  61  and the second projection part  64  are positioned alternately with each other, and overlap each other in the radial direction of the stator core  28 , so that the overlap part  4  is formed. The gap  5  is formed between the second flange parts  38  and  38  butted against each other in the overlap part  4 . That is, the gap  5  which is a space bent in a sectional view is formed between the first projection part  61  and the second projection part  64 . 
     The space of the gap  5  of the overlap part  4  and the space of the gap  5  on both sides of the overlap part  4  may be different from each other as shown in  FIG. 4 . Hereby, the size of the space of the gap  5  on both the sides of the overlap part  4  can be easily adjusted. Alternatively, the space of the gap  5  of the overlap part  4  can be made large. Besides, the space of the gap  5  of the overlap part  4  and the space of the gap  5  on both the sides of the overlap part  4  may be same. 
     Modifications 
       FIGS. 5A and 5B  are views each showing a shape of a gap  5  between plural second flange parts  38  adjacent to each other according to modifications.  FIG. 5A  shows the shape obliquely crossing the radial direction of the stator core  28 .  FIG. 5B  shows the shape widening in the radial direction of the stator core  28 . Incidentally,  FIGS. 5A and 5B  show the adjacent second flange parts  38  of the bobbin  30 , and the winding  40  wound around the bobbin  30  and the like are omitted. 
     As shown in  FIG. 5A , the shape of the gap  5  between the plural second flange parts  38  adjacent to each other is preferably the shape obliquely crossing the radial direction of the stator core  28 . According to this, the protrusion of the winding  40  from the space of the gap  5  between the adjacent second flange parts  38  and  38  can be prevented. 
     That is, a first projecting part  62  and a second projecting part  65  are positioned alternately with each other, and overlap each other in the radial direction of the stator core  28 , so that the overlap part  4  is formed. The gap  5  is formed between the second flange parts  38  and  38  butted against each other in the overlap part  4 . That is, the gap  5  which is the bent space in a sectional view is formed between the first projecting part  62  and the second projecting part  65 . According to this, the path of the gap  5  can be made long. 
     Besides, as shown in  FIG. 5B , the shape of the gap  5  between the plural second flange parts  38  adjacent to each other preferably widens in the radial direction of the stator core  28 . According to this, the protrusion of the winding  40  from the space of the gap  5  between the adjacent flange parts  38  and  38  can be prevented. Incidentally, the gap  5  is desirably formed such that the space widens toward the outside in the radial direction of the stator core  28 . 
     That is, the space of the gap  5  between the first projecting part  63  and the second projecting part  66  adjacent to each other is smaller than the diameter of the winding  40 . The gap  5  is formed such that the space widens toward the outside in the radial direction (arrow direction in  FIG. 5B ) of the stator core  28 . According to this, when the mold part  60  (see  FIG. 3 ) is formed, resin can be easily injected. 
     Robot 
       FIG. 6  is a perspective view showing a robot  7  to which the motor  1  of the embodiment is applied. 
     Next, the robot to which the motor  1  is applied will be described. Incidentally, a horizontal articulated robot and a vertical articulated robot are described as an example of the robot, the robot is not limited to these, and may be a double arm robot or another multiaxial robot. 
     As shown in  FIG. 6 , the robot  7  according to the embodiment is a horizontal articulated robot. The robot  7  includes a base  71 , a first arm  72 , a second arm  73 , a working head  74  and an end effector  75 . 
     The base  71  is fixed to, for example, a not-shown floor surface by a bolt. The first arm  72  is connected to an upper end of the base  71 . The first arm  72  is rotatable around a rotation axis along the vertical direction relative to the base  71 . A motor  1  ( 1 A) for rotating the first arm  72  is installed in the base  71 . 
     The second arm  73  is connected to a tip of the first arm  72 . The second arm  73  is rotatable around a rotation axis along the vertical direction relative to the first arm  72 . A motor  1  ( 1 B) for rotating the second arm  73  is installed in the second arm  73 . 
     The working head  74  is disposed at a tip of the second arm  73 . The working head  74  includes a spline nut  741  and a ball screw nut  742 , which are coaxially disposed at the tip of the second arm  73 , and a spline shaft  743  inserted into the spline nut  741  and the ball screw nut  742 . The spline shaft  743  is rotatable relative to the second arm  73  around an axis thereof and can move (rise and fall) in an up-and-down direction. 
     A motor  1  ( 1 C) and a motor  1  ( 1 D) are disposed in the second arm  73 . The driving force of the motor  1 C is transmitted to the spline nut  741  by a not-shown driving force transmission mechanism. When the spline nut  741  rotates forward and backward, the spline shaft  743  rotates forward and backward around the rotation axis along the vertical direction. On the other hand, the driving force of the motor  1 D is transmitted to the ball screw nut  742  by a not-shown driving force transmission mechanism. When the ball screw nut  742  rotates forward and backward, the spline shaft  743  moves up and down. 
     The end effector  75  is connected to the tip (lower end) of the spline shaft  743 . The end effector  75  is not particularly limited, and may be, for example, such as to hold a conveyed object or such as to process a workpiece. According to this, the robot  7  having the effects of the motor  1  described above can be provided. Besides, the highly reliable robot  7  can be provided. 
       FIG. 7  is a perspective view showing a robot  8  to which the motor  1  according to the embodiment is applied. 
     As shown in  FIG. 7 , the robot  8  of the embodiment is a vertical articulated (six axes) robot. The robot  8  includes a base  81 , four arms  82 ,  83 ,  84  and  85 , and a wrist  86 , and these are sequentially connected. 
     The base  81  is fixed to, for example, a not-shown floor surface by a bolt or the like. The arm  82  is connected to an upper end of the base  81  in an inclined posture relative to the horizontal direction. The arm  82  is rotatable around a rotation axis along the vertical direction relative to the base  81 . Besides, a motor  1  ( 1 E) for rotating the arm  82  is installed in the base  81 . 
     The arm  83  is connected to a tip of the arm  82 , and the arm  83  is rotatable around a rotation axis along the horizontal direction relative to the arm  82 . Besides, a motor ( 1 F) for rotating the arm  83  relative to the arm  82  is installed in the arm  83 . 
     The arm  84  is connected to a tip of the arm  83 , and the arm  84  is rotatable around a rotation axis along the horizontal direction relative to the arm  83 . Besides, a motor ( 1 G) for rotating the arm  84  relative to the arm  83  is installed in the arm  84 . 
     The arm  85  is connected to a tip of the arm  84 , and the arm  85  is rotatable around a rotation axis along the center axis of the arm  84  relative to the arm  84 . Besides, a motor ( 1 H) for rotating the arm  85  relative to the arm  84  is installed in the arm  85 . 
     The wrist  86  is connected to a tip of the arm  85 . The wrist  86  includes a ring-shaped support ring  861  connected to the arm  85  and a cylindrical wrist body  862  supported at a tip of the support ring  861 . A tip surface of the wrist body  862  is a flat surface and becomes a mount surface on which for example, a manipulator to hold a precision equipment, such as a wrist watch, is mounted. 
     The support ring  861  is rotatable around a rotation axis along the horizontal direction relative to the arm  85 . Besides, the wrist body  862  is rotatable around a rotation axis along the center axis of the wrist body  862  relative to the support ring  861 . Besides, a motor  1  ( 11 ) for rotating the support ring  861  relative to the arm  85  and a motor  1  ( 1 J) for rotating the wrist body  862  relative to the support ring  861  are arranged in the arm  85 . The driving forces of the motors  1 I and  1 J are respectively transmitted to the support ring  861  and the wrist body  862  by not-shown driving force transmission mechanisms. 
     As described above, according to the robot  8  of the embodiment, the effects of the motor  1  described above can be obtained. Besides, the highly reliable robot  8  can be provided. 
     Although the motors and the robots are described based on the illustrated embodiments, the invention is not limited to these, and the configuration of each part can be replaced by an arbitrary configuration having the same function. Besides, another arbitrary component may be added to the invention. 
     The entire disclosure of Japanese Patent Application No. 2015-029303, filed Feb. 18, 2015 is expressly incorporated by reference herein.